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CFD Consulting Services

CFD Consulting Services

At Predictive Engineering, we developed our expertise in computational fluid dynamics (CFD) consulting with years of CFD project work in medical, aerospace, marine, HVAC, civil and automotive. Our work has been extensively benchmarked by experiments and in-service testing.

Our portfolio of case studies provides hard evidence of our many successful CFD consulting projects: space-based communications equipment, bio-fuel combustion, aerodynamic drag, hydroelectric spillways, dispersed particle flow, data centers, power electronics and HVAC air handling systems, to name just a few. Besides these graphical writeups we also have a searchable text listing of our projects.

In CFD and really, all types of engineering simulation, experience is the key in knowing whether one has a cartoon or a true digital twin that can be taken from design into production. We feel that this is our competitive edge and our proven value to our clients.

If you have a need for experienced CFD consultants, Predictive Engineering has continually expanded its client base since 1995 with more than 800+ projects, so please feel free to contact us and learn more about our CFD consulting services.

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Exterior Flow of Preliminary Data Center Design

A proposed data center campus with two buildings is in the preliminary design phases. The architectural firm wanted to optimize the external flow to prevent exhaust and other contaminants entering the data center. Our computational fluid dynamic (CFD) experts were called upon to perform an air flow analysis of the chilling equipment through CFD modelling.  The analysis identified a potential issue with the equipment locations and allowed the client to make instrumental design decisions to allow for the best performance under mission critical scenarios. 

Data Center Design Change

Building on a previous analysis, our CFD engineers were called upon to re-evaluate the external flow of a data center.  The local municipality required visual screening of the roof mounted chillers, so a screen wall was added to the design.  The analysis was carried out to determine the effect of the screen wall on the chilling equipment.  Predictive’s CFD services provided a quick turnaround time, allowing the customer to stay on schedule with the unexpected design change.  

Exterior Flow of Pheonix Arizona Data Center

The goal of this computation fluid dynamics project was to evaluate the exterior airflow environment for a new data center, located in Phoenix, Arizona with backup generators running at full capacity. The primary concern was the intake temperature of chillers used in the HVAC system for the data center and Predictive’s CFD consultants determined the chiller intake temperatures for equipment verification. Wind rose data for Phoenix Sky Harbor airport was used to determine prominent wind direction and velocity for the site. The model is run with the three most prominent flow conditions with ambient temperature set to the ASHRAE N=20 Annual Extreme.

Thermal Analysis of Insulated Wall Used in Modular Housing Construction

Our client was concerned about the layout of plumbing lines within their insulated walls and resultant heat transfer through the wall.  During manufacturing, the placement of water lines would shift as insulation was added to the wall.  Their concern was these lines might freeze during high-wind and low-temperature events.  Predictive’s CFD consulting engineers constructed a detailed CFD model of the building and placed it within a virtual wind tunnel.  Heat transfer film coefficients were extracted from the building model and mapped onto the detailed thermal model of the insulated wall.  A transient thermal analysis of the wall showed that the water lines would not freeze if placed within the insulated wall within our client’s manufacturing tolerances. 

CFD Wind Loading on T303 LP-NRU Column ASME Section VIII, Division 2

A recently installed 50 ft tall LP-NRU column was noticed to be harmonically vibrating under moderate winds.  Our client was concerned that these wind induced loads might lower the fatigue life of the column as calculated by the ASME Section VIII, Division, Part 5.5 Protection Against Failure from Cyclic Loading.  A representative CFD model was built of the column and placed inside a virtual wind tower.  To capture the most extreme event, a wind load of 100 mph was evaluated.  Wind pressures were mapped onto a FEA model and a static stress analysis performed.  Stress results were interpreted based on the ASME code and the column was determined to meet its design fatigue requirements.

Intercon Power Boiler

Predictive Engineering continues to provide multi-physics CFD consulting services for power and recovery boiler applications.  This CFD combustion analysis project evaluated the baseline analysis for a power boiler operating with a steam production rate of 80.3 T/hr. The boiler operates primarily on wet hog fuel with a high moisture content, and supplemented by a small flow of natural gas. Future projects may be possible to evaluate a different supplemental fuel or redesign of the air vents.

Compressor Station – Alrewas

Predictive Engineering CFD services evaluated air flow modelling within two enclosure designs of natural gas pumping station at Alrewas. This computation fluid dynamics analysis evaluated a turbine driven unit and an electrical driven unit. For the turbine driven unit, potential zones of stagnant air were identified above the main compressor, behind the exhaust stack.  For the electrical unit, the primary region of stagnant air was on the inlet flow side in between air ducts toward the ceiling.  By identifying the locations of these stagnant zones, our client was able to optimize locations for fire and gas detection sensors.

Solar Balloon CFD Analysis

This CFD modelling project was performed for a young start-up group evaluating the potential lift for a solar powered balloon.  This solar CFD analysis evaluated their current design concept utilizing test results from material emissivity measurements to estimate the potential lift.  End results showed that although their initial structure weighed over 1 ton, there is still enough room for hundreds of pounds of payload. 

Check Valve Flow Analysis

The client is designing a check valve for an end client with applications toward a specialized refrigerant fluid.  Although the client has the means to test the valve performance with air, testing it with the actual working fluid would not be possible due to expense and complications with the test setup.  To estimate the performance, we performed a CFD air flow modeling evaluation of the check valve against the working fluid.  The model was first validated against air flow results from client testing.  The working fluid had a density 10 times greater than air, but significantly less viscosity.   Due to the higher density, the results showed volumetric flow rate was significantly less than air, but the mass flow rate was about 5 times greater.  The analysis provided enough backing information to the end client for them to finalize their design. 

Updated Downhole Jetted Ball Valve Design

This project extended a design revision evaluated for a jettable downhole ball valve. The computational fluid dynamics CFD analysis is a transient 3D simulation of the jetted ball valve under fluid forces. Our CFD analysis services evaluated the fluid flow through the valve with the client’s proposed design change. Through CFD analysis, we verified that this design would allow the pipe to operate at the required angle downhole. This capability fills a vital need for the end client.

CFD Analysis of Black Liquor Combustor

This CFD services project evaluated the redesign of a cylindrical black liquor combustor, from the baseline unit in operation, to a new design with higher load rate.  This multi-physics CFD analysis simulated the black liquor injection and combustion within the main chamber, along with heat transfer through surrounding refractory bricks, exterior air jacket and insultation to ambient conditions.  Four different design variants were evaluated to determine a lead design for production.  The new design provides significant improvement of heat transfer to the air jacket and near zero carry-over at the outlet stack. 

Recovery Boiler Model – Klabin

Our CFD analysis services evaluated the redesign of a recover boiler to extend the current firing rate capacity from 1,100 TDS/day to 1,540 TDS/day. The air flow modelling through a recovery boiler is extremely complex and requires experienced multi-physics CFD consulting services.  We developed a baseline model to replicate the current energy release and absorption of the original design. From the baseline design, four other design variants were evaluated. The evaluation of these designs showed the biggest impact was gained by optimizing placement of the air jets near the bottom of the furnace.

Compressor Station – St. Fergus

This project evaluated air flow within two enclosure designs of natural gas pumping station at St Fergus. This analysis evaluated a turbine driven unit and an electrical driven unit. For the turbine driven unit, potential zones of stagnant air were identified behind the inlet vents and above the compressor at the opposite end of the building. The electrical also had a similar pattern for flow stagnation. By identifying the locations of these stagnant zones, our client is able to optimize locations for fire and gas detection sensors.

Hammerhead Flood Control System

This CFD fluid dynamics project evaluated the dynamic loading on a flood barrier due to water in-rush at a code specification of 2 ft/s.  A VOF model of the barrier within a trough was setup to determine the pressures and forces of water impact on the structure.  With the model assumptions, the initial wave of water actually impacted the structure at 10 ft/s, and mapping these peak pressures to an FEA model showed the structure is able to handle this load with stresses well below yield. 

CFD Analysis of Data Center Conversion

The clients project focuses on a conversion of a building site within an urban setting to a functioning data center.  This project evaluated both internal and external flow to the end clients design specifications and metrics.  The exterior flow focused on potential recirculation of the chillers.  The analysis showed there was some potential for recirculation, but the values were within acceptable limits.  The interior flow was for a data center with over 30 MW of waste heat.  This analysis evaluate failure conditions for the planned built layout, and a potential maximum power density future layout.  The interior flow analysis showed there was some imbalance in the proposed layout, but temperature and flow distributions were excepted for the failure conditions.

Air Flow within a Parking Garage

Recent building renovations for a large store reduced the amount of natural open ventilation for the attached parking structure, which required an airflow modeling study to ensure minimum ventilation specifications were met.  The linear feet of open space available on the structure fell below code limits.  To locally improve airflow in the regions where the previous openings are now blocked, this project evaluated placement of fans into the parking structure. We evaluate different placements of fans into the garage to improve airflow within the confined regions and ensure air velocities would not be too high for the public.

Wind Loading on Ground-Based Antenna System

Our client had stringent reflector (dish) deformation requirements under operating conditions up to 120 mph.  The key measure of operating performance was the rms deflection of the dish.  Given these requirements, standard ASCE wind loading formulas wouldn’t suffice given that they typically over-predict the wind loads by a factor of 1.5 and do not allow for flow perturbations due to sub-collectors, feed towers or pedestal mounted electrical cabinets.  Predictive’s CFD consulting service showed that the dish wind loading was far less than the ASCE calculation and was non-uniform due to protruding electrical cabinets.  CFD pressures were then mapped onto a FEA model and the resulting rms calculation showed that the composite dish would meet their specifications.

Compressor Enclosures for Kirriemuir Facility

This project evaluated air flow for a turbine driven and electrically driven compressor station at the Kirriemuir compressor station.  The turbine compressor station had forced ventilation, although the report showed significant discrepancies between inlet and outlet flow.  To understand the sensitivity of internal air flow, Predictive’s CFD engineers performed two analyses varying the possible outlet flow locations that would be escape paths for the air.  The electrically driven unit was also a forced ventilation case and contained a much larger volume.  No flow conditions were provided for this unit, and engineering assumptions were made based on a previous CFD report quoting the targeted air changes per hour. 

Exterior Compressor Turbine Enclosure

This project evaluated air flow for an electrically driven compressor enclosure.  The driving goal for this analysis is to identify potential stagnant pockets of air within the enclosure that could lead to build up of combustible gases and potential fire risk.  A unique aspect for this enclosure was the lack of forced cooling within the building.  The building had large doors on either side that are normally open, plus vents on the lower side walls and upper end walls at the crown of the roof.  A significant component that could drive air within the building is exterior flow conditions.  Five different models were run for zero wind plus four forced wind conditions for the provided location.  From this work, our CFD consultants were able to pinpoint the optimum configuration to minimize the potential fire risk.

Fan Characterization for Custom Avionics Fan

The client required a custom fan solution to meet the environmental operating conditions for space flight hardware and required our experts to run a fan airflow simulation.  The client based their design off of an off the shelf product and wanted to use CFD to evaluate fan performance in parallel with rapid prototyping and testing.  The analysis evaluated the fan at two proposed operating conditions.  The initial results from the CFD analysis showed significant deviations from the targeted performance the client was trying to attain with their design.  The client fabricated and tested their design, which showed very good agreement with the CFD model.  Further evaluation of the CFD model showed there was potential for unstable flow conditions which could lead to reduced performance.  The client adjusted their fan design, guided by Predictive’s CFD consultants, and were able to get a significant improvement in results on a subsequent test. 

Jettable Ball Valve CFD Analysis

This CFD consulting project evaluated a proposed design for downhill drilling applications where opening a ball valve would be performed by mechanically pushing it out of the mandrel and jettisoning the ball into the on-coming flow.  A primary concern with this design was the potential of the fluid flow to push the ball back onto the valve seat.  Previous designs had tried to develop tooling to capture a returning ball, but this was deemed to complicated and could result in other failures.  The first CFD analysis mapped the potential forces on the ball valve at a target flow rate by steady state analyses, and determined the limiting angles where this device could be implemented.  The second step evaluated full dynamic free body transient runs of the jettison ball at various angles to show at which point it would either fall from the seat, or get pushed back.  These results were inline with the original steady state runs, but showed the simplifying assumptions made for those steady state runs were not as conservative as originally thought. 

Concrete Curing for Multiple Products

A follow on project with UCLA was performed to evaluate flow for concrete curing of CO2 sequestrating concrete products.  For this analysis, a custom chamber will be constructed from a shipping container, and must be able to handle three different product forms, concrete masonry units, segmented retaining walls, and large short pipe segments for manholes.  Although there was more freedom for positioning management components, the solid support racks for the products did not allow flow through the levels, and limited flow to above the surface.  The designs evaluated flow mixing by assessing mean age of air at the product surface, and transient models were developed to evaluate temperature stratification within the chambers.  Finally, a system model was analyzed to show air could be delivered uniformly throughout the chamber.  A single design was presented that could meet the curing goals for all three products, with small configuration changes for each product. 

Design Optimization for Ozone Distribution

Specific industrial processes can produce noxious gases and free radicals that must be eliminated before exhausting outside per regulations.  One method of handling these components is through the injection of ozone into process waste streams.  The important aspect for the ozone injection is the spread of the gas and residence time the gas has with the surrounding components.  The primary method of injecting the ozone into the process stream is using probes placed a specific location along the duct work.  The probe design for these studies was parameterized, and optimization studies were performed to evaluate optimal probe location, as well as probe design (number of holes, hole diameter, hole angle).  In the end, two different projects were performed for two different site locations.  The final designs produce a neat perfect distribution of ozone into the process stream. 

Lagoon Pond Flow

A CFD engineering service project was pursued to evaluate the flow within a 8.6 million gallon lagoon pond for agriculture use.  The driving concerns for this design were to ensure adequate mixing within the pond, adequate flow near the bottom of the pond for mixing debris, and avoidance of silt erosion on the side walls.  This fluid flow simulation showed higher flow rates could be attained in the pond with no danger of reaching wall stress levels for silt erosion on the side walls, and adjusting the positions of the inlets and outlets will lead to better mixing of flow within the ponds.   

CFD Analysis of 24-inch Fan Air flow Simulation

A performance analysis for a 24-inch diameter fan was performed in STAR-CCM+.  The fan airflow simulation was intended for agricultural applications.  In addition to expected performance, blade loading was evaluated at the intended operating point.  Numerical summations and pressure maps of the values were transferred to the end client for structural loading analysis. 

Carbon Concrete Curing Chamber

This air flow simulation project was for a start-up company that spun off of research from UCLA.  CFD was used to guide the design of retrofitting a conventional curing chamber for concrete blocks to take advantage of specialized concrete that can sequester CO2 from the fabrication process.  The challenge here was to integrate a new flow system into a current drying chamber with specified geometry restrictions, and meet the flow uniformity requirements as well as temperature and humidity distribution requirements for the process to meet optimal performance.  Much of the model evaluation was driven by evaluating mixing and mean age of air times at the surfaces of each block for each flow solution. Transient and quasi-steady state thermal analyses were performed to evaluate expected temperature variations throughout the chamber, and to evaluate potential solutions to meet design specifications.  In the end, two different designs were proposed, which were constructed on site. 

Gummy Drying Room

Drying of gummy candies requires a significant amount of time which leads to increased cost.  This CFD analysis evaluated the air handling of a new room design for the purpose of drying out gummies.  The first part of the analysis evaluated methods for achieving uniform airflow within the room.  This part was difficult since the stackable trays for transporting the gummies blocked and diverted much of the flow away from the pieces.  We proposed perforated floating wall that would provide a uniform flow across much of the room.  The second aspect of the analysis took advantage of multiphase modeling capabilities within STAR-CCM+ and modeled the drying of the gummies within the room.  Final design work by our CFD consultants evaluated a design modification that would reduce the overall drying time by 46%. 

Mixing Tube Analysis

This mixing CFD analysis evaluated the performance of a tube using a Greek key design in STAR-CCM+.  The primary gas component for the mixing tube was nitrogen, while impurities of oxygen, methane, and propane were added at a downstream location.  A mesh sensitivity study was performed to ensure accurate results would be attained.  This simulation was performed to provide confidence to in house simulations attained by a competing program.  

CFD of Building Exhaust Loading Dock

Employees at an office building in Chicago reported noxious odors at the top-level floor.  The assumed culprit for these odors was diesel exhaust due to delivery trucks idling at the loading back at the bottom of the building.  An exterior flow computational fluid dynamics simulation was performed for local wind conditions to determine what level of exhaust or other possible contaminated gases may be reaching the air inlets at the top story of the building.  Predictive’s CFD consultants showed a small percentage of diesel exhaust could reach the upper inlet under certain wind conditions, but there were lower building inlets that would receive a higher concentration of exhaust.  A design option was investigated to divert the air flow further away from the building, which did reduce potential concentrations to the top inlets. 

CFD Internal and External Flow for Two Story Data Center

This CFD consulting services project evaluated external and internal flow conditions for a new data center in Washington State.  A unique aspect of this data center design was that the data hall consists of two stories.   This layout made the building design challenging since heat generated by the servers on the lower level was exhausted through the roof of the building.  The design limitations for these exhaust ports resulted in recirculated flow to the upper levels of the data center.  The CFD analysis determined stack extensions were also required for the backup diesel generators to ensure exhaust would not enter the building CRAHs.  Internal flow on the lower flow was also challenged due to additional heat sources from lower level power supply units.  The analysis evaluated worse case operating conditions from the exterior analysis, and proposed solutions for managing the air flow within the lower level. 

Exterior Flow Analysis of Data Center with Roof Mounted Chillers

A well-known cloud services provider was planning a new data center which included roof mounted chillers. Their availability requirement for the data center is 5 nines (99.999% uptime), this included evaluating the performance of the chilling equipment with backup generators running at full load.  An exterior flow CFD model was utilized to determine the intake temperature of the equipment.  Wind Rose data was used to determine the worst-case flow conditions for the data center location.  The initial design showed undesirable results and various solutions were evaluated.  At the end of the day, our CFD engineers identified several problem areas with the initial design and determined potential solutions for mitigating the issues. The cloud service provider was able to move forward with high confidence that the new HVAC system design would achieve the 5 nines availability requirement.          

CFD Flow Optimization Analysis for Particulate Precipitator

Electrostatic particulate precipitators are used in the wood processing and many other industries to remove solid particulates and dust from process flows.  These units typically consist of banks of tubes, where there is a high voltage probe run down the center of each tube.  For the precipitators to work at peak efficiency, uniform flow must be attained.  For our client, Predictive Engineering’s CFD consultants built a parameterized model that allowed the placement “turning vanes” within their design and directly optimize the flow pattern using STAR-CCM+.  As part of our CFD services on this project, we also evaluated additional changes to the entire design to allow for improved flow coverage over the tube banks.  These units are very difficult to instrument to understand the actual flow through the units, so CFD became an important tool for a first look visualization into what was occurring within the precipitator.   

Server Pod CFD Analysis

Here was an interesting opportunity to model the intersection of onsite data computing power with land use restrictions.  Like other CFD HVAC data center projects we’ve done, there is always a concern of recirculation between server units.  In this CFD services project, the question was how close could we place self-contained server pods to avoid unit to unit recirculation and ensure that the computing power to land use is maximized.  In order to evaluate these designs, we created full-site CFD parametric models that captured the interior and exterior flow for each server pod, and allowed us to array these pods within the model and evaluate potential recirculation at various wind conditions.  Our results guided the end-client on where their limits were for locating the server pods.

Recovery Boiler Baseline Models

In 2021, Predictive Engineering CFD consulting services, in partnership with SHB Engineering, analyzed three different recovery boiler models for various clients.  These models captured detailed multiphysics combustion mechanics of solid black liquor vaporization and combustion by utilizing the coal combustion models and complex chemistry models within STAR-CCM+.  Additional models are incorporated within the main model to capture the combustion on the char bed and heat absorption through the superheater, generating banks, and economizers for the outlet flows.  Being a baseline model, there was data available on temperatures and CO emissions to verify the accuracy of the model to actual operation.  Our CFD services allowed SHB Engineering to recommend detailed boiler recommendations that would guarantee stack emission limits.    

Data Center Interior and Exterior Flow

A full CFD analysis was performed for a new data center located in Texas.  This analysis considered interior as well as exterior flows, where the primary concern for the exterior flow was emissions from the onsite diesel generators.  In addition to ensuring that the main data hall did not intake any polluted air, there were neighboring buildings that also had to be considered.  The interior flow analysis evaluated airflow from the CRAH units through the server racks and up the hot aisles.  The goal here was to evaluate a few different operating conditions to ensure that even flow was distributed to all the server modules and there was minimum recirculation on the exterior side of the CRAH units.  Results from Predictive’s CFD services allowed our client to quickly move forward with their proposed design. 

CFD of Turbine Enclosure

This analysis evaluated two turbine enclosure pump stations that were located on the North Sea.  Each of these pump stations had natural gas fired turbines to drive compressors for feeding the associated pipelines.  A big concern with these buildings is the possibility of a natural gas leak that could pool enough volatile to lead to an explosion.  Based on observed HVAC data and interior temperature measurements, our CFD consultants created a detailed CFD model of the interior of the building to evaluate the flow paths and locate regions where dead air may reside.  These dead air pockets would be potential regions where volatile gases could pool and hence appropriate located to aim detection equipment.

CFD Analysis of Regenerative Thermal Oxidizer

Regenerative Thermal Oxidizers (RTOs) are used for removal of volatile compounds from production processes in order to reduce harmful emissions.  This process requires flowing contaminated air through heated ceramic media and then up to a combustion chamber to reach temperatures of 1600°F.  Our CFD consulting services were engaged to performed a thermal-flow analysis on a new design for one of these units to verify that uniform flow could be attained across the ceramic media, proper temperatures were attained, and that residence times were sufficient for the reduction processes.  All the various flow paths were evaluated to ensure that no dead and untreated air would be present to escape the unit. 

Smoke Dispersion for Luxury Hotel

A client came to us with an interesting problem for a new luxury hotel.  They were receiving complaints of smoke from guest at an elevated pool deck, and more worrisome from neighboring building owners.  The primary cause was linked an outlet chimney for a wood-fired oven located on the side of the building, but just below of the pool deck.  CFD was requested to verify whether there were any merits to the complaint claims, at which point we showed there were certain wind conditions where the smoke would engulf the pool deck and impact HVAC units on neighboring buildings.  Results from this CFD services project showed that unfortunately, one should just not barbeque.

Motor / Inverter Thermal Analysis for Electric Aircraft

Electrification of aircraft is a large push with many startups and industry leaders.  In this industry, weight is a driving concern, not only with the batteries, but also with the electric motors and electronics used to drive the propellers.  The primary tradeoff to driving down the size of the motors and drives is managing the heat generation.  In this CFD services project, we performed a full detailed conjugate heat transfer analysis for a proposed prop driving compact motor / inverter design, with the goal of understanding the component temperatures and evaluating potential cooling designs.  We performed side optimization studies to evaluate different fin arrangements for exterior air flow and proposed changes to the rotor and endplate structures to improve cooling to the magnets. 

Multiphase CFD Analysis of Propane Vaporizer

Propane vaporizers are used vaporize liquid fuel and enable a more efficient and complete drawing of the fuel tank.  Operating conditions at very low temperatures can significantly increase the pressure drop across the unit, thereby reducing the overall flowrate and effectiveness of the vaporizer.  Our CFD consulting engineers analyzed a current unit in STAR-CCM+ to capture the vaporization of liquid flow through the unit utilizing Rohsenow wall boiling models with volume of fluid (VOF) models.  The model was validated against three operating conditions where the client had test data available.  From the validated model, we evaluated a couple design changes to reduce the flow losses and improve performance at low temperatures. 

Building Louver Flow

Louvers are commonly used on buildings to allow flow of air into and out of the building, while preventing rain and debris from entering the building.  The vanes on the louvers can create a significant pressure drop, which is important to understand due to the impact it can have on the building’s HVAC system.  Typically, the louvers are tested to industry standards, such as ANSI/AMCA 500-L-12 to understand the expected pressure drop at set flow rates.  Our client was under a crunch to understand a new design and did not have time to fabricate and perform testing.  Our CFD engineers performed aerodynamic simulation on two design configurations in our CFD digital-twin sandbox (STAR-CCM+) per operating conditions outlined in the AMCA standard.  Results from CFD engineering services verified that the louver designs operated at similar pressure drops as those measured by the standard and our client was able to proceed forward with their end customer. 

CFD Optimization for Sow Farrowing Hall

Farrowing halls are used for sows nursing young piglets in the pork industry.  It’s important to keep the sow cool and comfortable, but not get the young piglets too cold.  Overhead vents are placed above the sow in order to allow cooler fresh air into the building and keep the animal comfortable.  In this project, our CFD consultants were tasked to help optimize the vent design to direct specified flow rates directly on to the belly of the sow.  The optimization considered the sizing and door angle for the vent operating at a nominal building pressure drop.  With optimization, we were able to automatically evaluate over 150 design choices to provide a single design option that works within the requested operating range. 

Inlet Vent for Chicken House

Large facilities for raising chickens are common in the agriculture industry for poultry production.  Air movement within these facilities is key in order to keep the temperature and humidity in a comfortable zone for the chickens on the floor.  It is common to use inlet vents on the sides of the walls to allow fresh air into the building, but there are concerns that when the temperature outside is cold, the incoming air must be properly dispersed to prevent pockets of cold air on the floor where the chickens are.  Our CFD-HVAC consultants performed a CFD analysis of a proposed inlet vent design to evaluate the performance  of sufficiently dispersing incoming cold air when there was a 50°F differential between the outside and inside building temperature. 

CFD Flow Analysis of 3 Wheeled Electric Vehicle

Computational fluid dynamics (CFD) was used in this aerodynamic simulation to evaluate the drag coefficient of a 3 wheeled electric vehicle (EV).  The OEM needed to maximize the range of the vehicle and, of course, the drag coefficient has a direct impact on range.  Predictive Engineering was hired to evaluate and recommend improvements to the design.  The analysis of the existing design calculated the drag coefficient to within 5% of the value calculated from a coast down test.  Once the baseline model was established several design iterations where analyzed to minimize the drag.  The CFD analysis allowed Predictive Engineering to recommend design changes that reduced the original drag coefficient by over 40%.   

Power Plant Exhaust (CO2) Sequestration

Researchers at UCLA are developing methods to capture carbon (CO2) from power generation under a project for the NRG COSIA Carbon XPRIZE.  CO2 is pumped over a specialized concrete material that absorbs the carbon and also adds strength to the material.  To scale this project up to commercial viability, the material was molded into masonry “A”-blocks, racked into 4 x 4 x 8 ft fork-lift pallets, and then inserted into a standard 40 ft long shipping container.  CFD analysis was then used to optimize the flow of carbon rich exhaust gas into the container and around the blocks.  The goal of the CFD modeling was to ensure uniform coverage of the blocks and maximum residence time for absorption (i.e., uniform near-surface gas velocities).  Project goals were achieved and our team of CFD consultants look forward to continuing this project into 2021 with our colleagues at UCLA.

Outdoor Electronics Cabinet

Electronic cabinets for exterior applications must be able to survive and operated in extreme environmental conditions.  Predictive Engineering provided thermal-CFD consulting services to analyze air flow and temperature distribution within a UPS (uninterrupted power supply) cabinet for telecommunications.  HVAC units provided cooling, but the insulated walls are relatively thin compared to typical building applications, so external heat gain from exterior ambient temperatures and solar radiation was a thermal driver.  In addition, heat gain from and air flow from the individual electronic components were also included.  Predictive worked with the end customer to provide suggestions for improving air flow within the unit to reduce residence time and temperatures for the internal electronic devices. 

CFD Analysis of Air Handling Units (HVAC for Large Office Buildings)

Predictive Engineering provided CFD services to evaluate air flow through building integrated air handling units which included flow through filters and heating/cooling coils.  The air handling units were built around building support columns and features that locally neck the flow in specific areas.  Industrial cooling coils operate at peak performance under uniform air flow conditions which avoid localized velocity peaks.  Excess velocities may lead to condensation and other follow-on problems.  The analysis showed that the design considerations proposed were sufficient to maintain uniform flow through the cooling coils and avoid condensation issues that had plagued the units in the past. 

CFD Parameterization and Optimization of Air Mixing in Office Tower Fan Room

One of the hardest challenges in fluid system design is successfully mixing streams of warm and cold air.  For a new office tower located in Chicago Il, we utilized the CFD design optimization capabilities within STAR-CCM+ to help design the HVAC fan rooms where warm return building air mixed with fresh cold winter air.  In worse case scenarios, the temperature difference between these streams can be 48°C.  To tackle this challenge, the models were parameterized to reposition heating elements, control damper settings, and adjust baffle features to ensure sufficient air mixing for HVAC operation. 

CFD Analysis of Interior Grow Room Facility

This CFD consulting project was our first of many subsequent grow room CFD analyses.  Working closely with a major supplier of grow room equipment and grow products, we have optimized flow patterns, humidity levels and temperature gradients in several large grow facilities across North America.  Airflow, humidity, and temperature are three driving factors that will ensure successful growth of the crop.  The focus is to develop parameterized models that can be used to select the number, position, and type of fans and other equipment for implementation within the grow rooms. 

Data Center Exterior Generator Exhaust Dispersion

This analysis investigated the exhaust plume of a series of backup generators for a data center.  The goal was to determine if the exhaust fumes would not only contaminate the supply air of the cooling equipment in the data center, but also the air supply for an adjacent office building.  The analysis assumed the worst-case atmospheric wind conditions and direction, that would push the exhaust flume to the data center and adjacent building.  By tracking the particulate matter in the hot exhaust air, the CFD analysis confirmed that the HVAC equipment was supplied with clean air. 

Flue Stack Gas Dispersion

This analysis evaluated a flame out scenario where toxic gases are emitted from a flue rather than safely combusted.  Different atmospheric conditions and wind speeds were evaluated to determine safe distances for locating structures and personnel so that their exposures would not exceed specified ppm levels as set by OSHA.  The wind conditions were driven by Pasquill Stability class criteria which uses a logarithmic increase in wind velocity with respect to height, and linear slope on temperature to impact flow stability. 

Sediment Pipe Flow

This multiphase fluid flow simulation study was performed on a sea-water dredging system to evaluate the sediment flow path of fine silt injected into the stream. Fine silt sediment was injected into the pipe system fed by sea-water.  During design validation testing, the client was concerned that inline concentration measurements of sediment were far lower than expected values.  Predictive Engineering performed a particle flow analysis in STAR-CCM+ using the Lagrangian multi-phase models to track the paths of particulate flow.  The CFD analysis showed that the bulk of the sediment flow was swirling around the walls of the pipe and by-passing the measurement ports.  Our CFD consulting work validated the system for eventual certification.

Power Boiler Combustion Analysis with Solid Mass Bio-Fuels

To demonstrate the capabilities of STAR-CCM+ for handling complex combustion processes, the operation of a power boiler was analyzed.  The power boiler was dual-fueled with natural gas injection ports located about 1/3 the height up the tower and wet bark fuel injected toward the bottom end.  The combustion processes were simplified to 3 step reactions for methane combustion using an Eddy Breakup model.  The solid bark fuel was modeled with the coal combustion model available in STAR-CCM+.  This model captures the evaporation of water and devolatilization of combustible gases from the solid fuel, as well as oxidation of fixed carbon (char) to carbon monoxide. 

Recovery Boiler Combustion Analysis

A CFD analysis was performed on a newly built recovery boiler to estimate operational temperatures, CO emissions, and NOx emissions.  The recovery boiler is fueled solely by black liquor that is sprayed into the lower furnace.  The coal combustion model defined by Lagrangian particles was used in STAR-CCM+ to model the drying, devolatilization, and char burning reactions that occur to the black liquor.  One challenging aspect of black liquor combustion is the droplets swell in size (4 to 5 times original diameter) during the drying and devolatilization reactions.  These effects were captured by using customized functions to simulate particle swelling during combustion.  Analysis results were comparable to results obtained from previous analyses on comparable boilers. 


Ball Valve Purge Analysis

Large ball valves for industrial processes require purging systems to ensure particulates do not interfere with sealing surfaces and overall valve operation.  CFD analyses were performed on two different ball valve designs to assess flow coverage.  The analyses assumed viscous oil and steam at elevated temperatures as the primary and purging fluid. The first steady state analysis was performed on a 36 in. diameter ball valve that had a continuous purge flow system.   The second analysis was a transient analysis of a 6 in ball valve transitioning from open to close position and return.  Although the analysis showed some areas of preferred flow, the client felt the analysis showed there was adequate flow for purging, especially around the rear seal.  Additional design recommendations were suggested to further improve flow on their designs.  

Thermal and Flow Analysis of Subway Car

Predictive Engineering provided CFD consulting services (analysis and expertise) for the design of a subway car to ensure that flow and temperature performance would met the stringent design specifications as laid out by the end client.  This project was divided into three stages to assess flow uniformity through the subway car, temperature distribution through the passenger and front driver cab, and power electronic temperatures located in the under-carriage.  Original assessment of flow uniformity showed that the vendor design was very far off from meeting the design specification.  Predictive suggested methods to meet the flow uniformity requirements by optimizing baffle placement through the main air plenum.  Flow balancing was quite interesting since the basic Bernoulli approach didn’t quite capture the flow characteristics of the tapered plenum.  As HVAC experts know, air flow has momentum and creating balance flow is a blend of Bernoulli and billiards where the air flow is treated as bouncing off of deflectors and creating high/low pressure regions.  After setting the optimized flow patterns, we assessed temperature stratification throughout the front cab and passenger cabin under various thermal conditions including summer and winter operations above and below ground.  These thermal loads included relevant exterior temperatures, solar radiation, passenger loads (real and latent heat), and internal electronic loads.

Sediment Pipe Flow

A CFD services study was performed on a sea-water dredging system to evaluate the sediment flow path of fine silt injected into the stream. Fine silt sediment was injected into the pipe system fed by sea-water.  During design validation testing, the client was concerned that inline concentration measurements of sediment were far lower than expected values.  Predictive Engineering performed a particle flow analysis in STAR-CCM+ using the Lagrangian multi-phase models to track the paths of particulate flow.  The CFD analysis showed that the bulk of the sediment flow was swirling around the walls of the pipe and by-passing the measurement ports.  This analysis was able to help validate the operation of the client’s system for ship certification.

Power Boiler Combustion Analysis with Solid Mass Bio-Fuels

To demonstrate the capabilities of STAR-CCM+ for handling complex combustion processes, the operation of a power boiler was analyzed as a CFD consulting services project.  The power boiler was dual-fueled with natural gas injection ports located about 1/3 the height up the tower and wet bark fuel injected toward the bottom end.  The combustion processes were simplified to 3 step reactions for methane combustion using an Eddy Breakup model.  The solid bark fuel was modeled with the coal combustion model available in STAR-CCM+.  This model captures the evaporation of water and devolatilization of combustible gases from the solid fuel, as well as oxidation of fixed carbon (char) to carbon monoxide.

Transient CFD Thermal Modeling of High-Intensity Light Heating of DNA Organics

The examination of biological material is often done within an aqueous medium or in a manner that requires that the organic material is not severely heated. In this CFD services work, we were tasked with creating a nano-scale transient thermal CFD model with water flow on one side of an integrated circuit (IC) and natural buoyancy air-circulation on the aqueous side of the device. Thermal energy due to the high-intensity illumination light source for imaging was simulated by first hand-calculating the light energy to heat flux number flux and then correcting this value based on absorption factors due to optics and other material transmissibility’s. The CFD model was then able to predict the temperature rise within the organic material due to their imaging requirement. This work helped our client develop an optimum design quickly and at lower cost than constructing laboratory prototypes.

Thermal Modeling of High-Temperature Graphitization Furnace

In support of an ASME Section VIII, Division 2 thermal-stress analysis of a high-temperature furnace, several CFD investigative models were developed to bracket the thermal response of the system. A key question was how the graphite felt within the furnace would transfer heat to the inside steel shell of the furnace. Although the shell was water cooled, we needed to understand what might be the range of interface temperatures between the graphite felt and steel shell. A simplified 2D model was created where only radiative heat transfer was allowed across the interface and then only conduction. On the water cooled side of the shell, water was assumed to flow at a very reduced rate to mimic worst case conditions. This simplified model indicated that the graphite felt dominates the temperature response since the heat flux through the felt from 1650°C to the steel shell was minimal. Given the bracketed thermal response, the thermal-stress analysis was then executed with more reasonable confidence in the final numbers.

Improving the Thermal Performance of Bio-Fluid Containers

Of course, we all enjoy keeping our cold drinks cold and our hot drinks hot, but the thermal physics of designing such containers is quite complex. The margin in the numbers between hot coffee after six hours versus twelve is very slim given the temperature delta between the fluid and the outside, and of course, our preferred drinking temperature. Basically this means, the container must be very well engineered to maintain vacuum conditions between the linear and shell and that any conduction paths completely shut down. Our CFD engineering services concentrated on verifying our clients 1D thermal conduction-radiation-convection path and then creating a full 3D model of the container that could capture the internal buoyant convection of the fluid coupled to radiant heat transfer across the vacuum and finally to the external ambient air. The analysis was fully transient and provided insights into the dominate energy transfer paths through the container.

Flow Analysis of Novel Syringe for Ocular Medical Application

This CFD services work supported an advanced medical R&D effort to better understand how their syringe injection flow rates would vary given a range of plunger forces. The design was unique but attached to a common Luer system. The CFD modeling started out using an axisymmetric approach for efficiency but then as the project morphed, the model was setup as a full 3D idealization of the syringe and tissue system. Description and interpretation of the flow results were of pivotal importance to the group given that it provided them with on-demand CFD specialist without the cost and training of having a full-time engineer.

CFD Modeling of Flow Mixing in Large Wastewater Basin

This project somewhat completes our simulation of water treatment systems. In prior work for another client, we studied the flow of water through a flocculation basin and up through separators and then into the clear well. In this project, it was just the opposite since it considers the flow mixing of wastewater in a 110 ft diameter basin. Our client needed quantifiable proof that their mixing system would ensure complete mixing throughout the basin. Working collaboratively, the CFD model was constructed to represent the interior of the basin with known flow obstructions, skimmers and pumps. Flow results indicated that one 50HP mixer could provide complete mixing in the basin. Our CFD engineering report was then leveraged to demonstrate similar mixing confidence in other basins.

Thermal-Flow Analysis of Large Composite Curing Mandrel

Modern jet engines are getting bigger and also lighter; e.g., the prior titanium blade-out shield is now a carbon fiber composite. Manufacturing large diameter composites with tight tolerances requires high precision in the curing and cooling process. The CFD model simulated the cooling cycle of the system (composite and tooling) from its curing temperature down to room temperature. Results were verified against prior experience and hand calculations.  

Mapping Envelopes of Expected Dynamic Behavior using CFD Flow Loading

Recently we just completed a coupled computational fluid dynamics (CFD) and finite element analysis (FEA) project on a “turbocharger” to an existing 60kW gas turbine. The energy physics of this turbocharger is to spray water droplets into the inlet of the compressor side of the turbine thereby increasing the density of the already 100% saturated air. This heavy air mixture is then combusted with increased gas flow, yielding a 10 to 15% boost in energy output from the turbine. In other words, one can take a 60kW turbine and turbocharge it to ~70kW at no more than 1% of the original turbine cost. The challenge for our client (an electrical utility) is that this device is bolted onto the flow housing inlet to the gas turbine. If this device fails, then parts would directly enter the turbine, leading to a very expensive repair operation plus unexpected disruption to the utility’s power grid. The graphics down below provide a generalized description of the CFD and FEA models. Air inters through the filter house and then around the housing, through some guide vanes and then into the compressor-side of the gas turbine. The CFD analysis (STAR-CCM+) provides us with component pressures over the housing and the water spray system which were then mapped onto a FEA model (FEMAP). The FEA model was then exercised through a static stress, normal modes and modal frequency analyses (NX Nastran). To verify this work, a CFD mesh convergence study was done and the FEA work was checked against hand calculations. Results assured the client that the add-on device was more than structurally adequate and could easily handle the power plant’s dominate 60Hz vibration plus any multiples.

Chemical Vapor Deposition (CVD) Reactor CFD Analysis

Temperature control in chemical vapor deposition (CVD) reactors is critical for creating high-quality product with minimal inclusions and defects. However, the thermal behavior of the reactor has a major impact of the structure itself, namely at flanges and other pressure-boundary seals. When a client wanted to redesign the main pressure vessel flange of a CVD reactor, transient CFD analysis was used to calculate the temperature profile of the reactor throughout the complete CVD processes. These temperature profiles were then used as inputs for an FEA analysis, allowing the client to optimize the new flange design using a robust set of loading conditions.

Flow Analysis of Novel Household HVAC Flow Vent

A local businessperson was on a quest to develop the next generation of household heating, ventilation and air conditioning (HVAC) floor vents. Prototypes were built and general flow intuition indicated that this new vent design should perform as well if not better than current designs. The challenge was how to quantify this intuition. Of course, an experiment could be performed but sometimes it is only necessary to quantify the difference and not be concerned with an exact measurement. We built side-by-side CFD models of the new vent and compared it with a standard floor vent. To no one’s surprise, the flow patterns were almost equivalent given standard house dimensions (i.e., ceiling height and room size). Armed with these results, the businessperson was able to move the project forward.

Rapid Depressurization Analysis of a Large Composite Container

A transient CFD analysis was performed to determine the maximum pressure difference that may occur during the rapid depressurization of the container via the triggered burst of the eight explosion vents at the ends of the container. The burst pressure of the vents was assumed to be at the upper limit of 1.25 psig. The container was assumed to be at nominal atmospheric conditions during a rapid cabin depressurization event creating a pressure delta of 8.3 psig between the inside of the container and the aircraft cabin pressure. Leveraging symmetry, it was possible to model the system using quarter-symmetry and then placed within an external air volume the simulated a typical aircraft interior, albeit in quarter-symmetry. Given the reduced model size, the transient CFD simulation ran in a couple of hours and generated the required transient depressurization curves to predict the maximum internal pressure that might occur within the container. To verify these results, the mesh was refined through several iterations. The calculated maximum internal container pressure was then used in the static stress analysis of the container by Predictive Engineering.

CFD Flow Modeling in a Cement Plant Bag House

This project was very much déjà vu since one of our first CFD consulting projects was a similar bag house model done in 1998. In this early model, we optimized the flow in 2D and then only made a few 3D runs since the analysis time was in days. Fast forward to 2015 and everything is in 3D and run times are in minutes given multi-threaded CFD solvers and faster hardware. The objective of this CFD service was to minimize the entrapment and accumulation of cement particles within the bag house. Along with minimizing the head loss the client wanted the manifold air flow balance to equally feed all twelve dust bags. The tuning mechanism was through the use of large vanes strategically placed within the manifold. After several iterations, the final design provided a consistent flow profile and avoided the settling of particulate at the bottom of the hopper.

Laminar Flow Modeling of Flocculent Water Treatment Basin

Drinking water every day from the tap, it is nice to know that the science and technology of water treatment is continuing evolving toward better processes. In this CFD project, we were tasked to investigate the flow of water within a large flocculation basin. Our client had years of experience in building treatment basins and wanted to improve their performance by ensuring that the flow behavior was as laminar as possible prior to passing through a series of flocculent traps (mechanical filters). The CFD model consisted of energy dissipaters (parabolic shaped plates with variable patterns of holes) and then large resistive blocks to simulate the mechanical filters. Interesting enough, our flow studies showed that their system was optimized and that further changes would be unnecessary given manufacturing versus performance constraints.

Electronic Cooling of High-Density Packages for Thermal Burn-In

Electronic devices used to be well-known to suffer from infant mortality. That is, they would work great for a few weeks or months and then just die during normal operation. The cause could typically be traced back to an overheated circuit or solder fatigue at the IC level; nowadays, advances in circuit testing and electronic device burn-in has largely solved this problem. Whereas circuit testing is a lot of signal processing, device burn-in is very thermal-mechanical with the controlled heating and cooling of the device and if needed thermal-cycling of the device to ensure its long-term survivability. Our client had the challenge of thermal-cycling thousands of electronic devices as rapidly as possible in a completely automated environment. They were recommended to Predictive given our past CFD consulting services for another company (it is small world). The CFD work consisted of local thermal-fluid models to determine optimum packing density of the devices for a given airflow to maintain tolerances of plus or minus two degrees centigrade. This local model was then simplified and used in a cabinet level model containing thousands of these devices. Airflow rates were determined for the given heating and cooling cycles along with ramp times. The overall model was then used to size the system’s thermal units and to convince the end-client that this novel design would work as intended.

HVAC Air-Handler Flow Blending Baffle Optimization

Roof top mounted air-handlers for large buildings are designed to balance foot print size and air handling capacity. To meet these specifications, the air blending chamber or mixing chamber between return air and outside air (make-up air) should be as small as possible yet still provide sufficient mixing that cold or hot channels don’t develop within the system. Traditionally, a large circular aluminum blade is used to direct the air into a similarly large chamber to limit head loss and provide sufficient mixing. This CFD flow study investigated a novel system of aerodynamic flow tubes combined with perforated plates to create a compact mixing chamber with similarly low, head-loss characteristics.

CFD Analysis of Automated Test Stand for Solid-State Memory Devices

This project was a combination of air flow optimization through constricted passages for minimal head loss and the development of internal baffles and air straighteners to create an even blanket of air flow over racks of solid-state memory devices.  The thermal challenge was to ensure uniform air flow across the devices that would ensure as uniform heating and cooling rates and then maintain steady-state thermal conditions for burn-in testing.  The analyses work was coordinated tightly with the client’s engineering team to ensure that the baffle design could be easily manufactured and that the thermal profiles would meet their specifications.

Natural Convection CFD Analysis on DC Power Inverter for Mass Production

A solar panel mounted DC power inverter was thermally analyzed using CFD to determine it maximum operating conditions in still air.  Natural convection and radiation were enabled along with conjugate heat transfer between the printed circuit board (PCB), mounted integrated circuits, silicone based pottant and finally to its aluminum casing.  Thermal CFD results were validated against experimental thermal images.  The thermal work was then mapped onto a LS-DYNA model to simulate the expansion of the pottant against the chips and casings and to evaluate the overall water tightness of the casting on board level chip stress.

Bent Axis Hydraulic Pump Yoke - Pressure Drop Analysis

This analysis used a Computational Fluid Dynamics (CFD) model was to determine the pressure drop through a bent axis hydraulic pump under operating conditions.  This analysis investigated multiple orientations of internal components affecting the flow path as well as multiple flow directions. 

CFD Pressure Drop Analysis of a Dump Truck Frame

Engine exhaust is routed through the ribs of the truck body to heat the body and help prevent dirt from sticking.  The pressure drop of the exhaust through the frame cannot exceed the maximum allowable backpressure of the engine.  This analysis simulated the flow through the truck frame.  The CFD model of the frame was idealized as a solid air volume and with the adjacent steel structure.

CFD Analysis of Parks RFTA Army Reserve Center

The objective of this analysis was to test the cooling and air circulation capabilities of a “green” building with ventilation driven primarily by natural convection.  A large south facing atrium was used to create a chimney effect that would draw cool outside air in through the offices of the building.  The results of this analysis provided the client temperature, air velocity, and flow path throughout the facility.

Relief Gate Flow Analysis

This CFD investigation was performed during the design process of a water control gate.  The volumetric flow rate for the gate was given and the designers needed to be sure that the pressure drop across the gate did not exceed project allowables.  In addition to the pressure drop requirements, it was important to determine the force on the gate from the fluid.

John Deere Manufacturing Building CFD Analysis

The objective of this analysis was to verify the HVAC design of a large manufacturing facility.  The facility provided a complex thermal problem with many localized temperature extremes.  Additionally, the facility experienced extreme winter and summer conditions that would test the limits of the HVAC design.  The CFD model included circulation fans, HVAC ducting, gas heaters, lighting, air drafts from unsealed doors, heat loads from manufacturing equipment, and other temperature and flow inputs.  The results of this analysis provided the client temperature, air velocity, and flow path throughout the facility.

Wind loading on Airport Noise Adsorption Wall

Wind loading conditions up to Beaufort Scale 7 were simulated on a large mobile wall structure using CFdesign.  Wind load forces were directly mapped from CFdesign to Femap for structural analysis.  Wind loads were checked against their upper limits using ASCE 7-02. The wall was designed to fit within a shipping container and is to be fabricated using standard steel tubing.  The analysis work followed Universal Building Code (UBC) specifications for structures near human occupancy with a safety factor of 2x.  Extreme wind loading conditions were also modeled and a nonlinear buckling analysis was performed to ensure that the wall would not collapse. 

Thermal Fluid Analysis of Buried Pipe 

This was a very interesting CFD analysis of buried plastic pipes under about eight feet of soil. The CFD work was coupled with a stress analysis models to facilitate a diagnosis of a pipe rupture problem.  The CFD model was used to generate thermal profiles in buried piping vaults and in adjacent piping runs (SCH 80 PVC piping).  Temperature profiles were then mapped onto the FE model to make predictions about piping stresses.  The stress results correlated extremely well with observed in-field piping failures.

National Institute of Science and Technology (NIST) Investigation of Respirator Fit and Function

This was an in-depth detailed project to study the fit and function of a fireman type respirator mask.  LS-DYNA was used to perform the fit study of the mask against a simulated human head. The silicone material model was easy to obtain while that for human tissue required some investigation.  The best material model fit for human skin was that of a soft rubber compound within an elastic membrane. A transient flow study within the nose cup of the respirator mask was conducted using CFdesign.  Inhalation and expiration studies were conducted using standard respiratory breathing curves.  Transient flow results indicated that the standard respirator mask creates some turbulence during inhalation that might cause breathing difficulty.  Research papers are in process to elaborate upon these results with a shared co-authorship.

HVAC CFD Modeling of Large Power Plant Buildings

Gas turbines for power generation, even with the best co-generation sub-systems, create significant heat loading within the power plant building.  To complicate this matter, new noise standards for power plant buildings has required that these buildings be closed to the free flow of air from the outside.  In essence, you have a heat generation source within a closed environment.  To obtain tolerable internal operating temperatures through-out the year, a full computational fluid analysis study was done on two large power plant buildings. One building was a standard large hall configuration with the steam co-generation turbine at one end of the building the hall containing two large gas turbines.  The other building used one massive gas turbine with a large HRSG (Heat Recovery Steam Generator) feeding to a steam generator.  The building also contained two aux. boilers.  In both buildings, cooling control was the biggest challenge since doors could not be opened during summer due to the noise limitation specification.  As such, all cooling was by air conditioners.  To limit the cost of air conditioning, only areas where human occupancy might occur were cooled letting other areas be hotter than normal but not to such an extent that safety was compromised.  The CFD models were very large running in the range of 10 to 15,000,000 elements.  Air flow was managed by placement of air conditioners and vents to the outside since makeup air was part of the equation.  Winter conditions were also evaluated with building skin temperatures as low as 1.4 F.  The buildings have been placed into service and are operating within the stated specifications as designed.

CFD Thermal Analysis of Speaker Enclosure

Compact stereo devices generate significant amounts of heat due to the high power generation of the amplifiers and face difficult cooling situations due to their tight enclosures, human safety concerns and that fan cooling due to noise generation is not permitted.  CFD studies were thus focused on spreading the heat into surrounding structures or increasing the natural convection heat flow through larger heat sinks or better placement of these sinks.  At times, the CFD work indicated that the design was simply unfeasible and a major rework of the speaker device was required.  Most of these models were run as coupled thermal-fluid mode where air buoyancy (natural convection) was coupled to the solid chip components of the model.  This is also known as conjugate heat transfer or conduction-convective heat transfer.  In all, a desktop I-Pod stereo system, an amplified boom-box and several powered desktop speaker systems were successfully analyzed for thermal performance.  Geometry was prepared from Pro/E and all analysis work done with CFdesign. 

Scissor Lift Wind Load Analysis

A scissor lift with sensitive electronics equipment needed to be analyzed to determine the wind conditions it could withstand. The CFD study allowed the client to give a wind rating with high confidence. It additionally saved the client thousands of dollars since they did not need to do physical wind tunnel testing. The tipping force was calculated at varying extension heights.  The computational fluid dynamics (CFD) analysis was run to determine the force on the structure at varying wind speeds.  These forces were verified against wind load calculations from ASCE 7-02, Minimum Design Loads for Building and Other Structures.

Parametric Wind Force Analysis on a Residential Roof Mounted Photovoltaic Panel

The PV system consists of 4 modules that are aligned edge-to-edge to create an overall panel having dimensions of 130" x 62" x 2". The panel is mounted to the roof with 8 mounting brackets. The mounting brackets are 4" wide and are attached along the bottom and top edges of the PV Panel. Given this geometry, the panel was idealized as a 2-D structure. The PV Panel was mounted mid-way up on an inclined roof (10, 18 and 30 degree slopes were investigated). Mounting details and roof geometry are provided within the body of this report. The PV Panel height was investigated at 3.25, 4.5 and 6.0” heights. At the lowest level (3.25"), the rear opening underneath the aluminum rails and the concrete roof was blocked. At the 4.5 and 6.0" heights, the PV Panel was open on both ends. The wind load for this simulation was a constant 100 MPH air stream. Steady-state conditions were assumed.

Heat Sink Thermal and Pressure Drop Analysis

The objective of this analysis project was twofold; determine the temperature of the heat sink during steady state operation and determine the pressure drop across the system. The temperature of the heat sink was critical as it had to be able to adequately cool the attached electronics. The pressure drop was important because the required flow rate and back pressure had to be taken into consideration when designing the air handling system. The system was analyzed under a range of air flow rates and inlet temperatures providing enough information to end client to interpolate for different operational scenarios.

Phoseon Thermal Analysis

Phoseon is an innovative leader in the field of LED light bars that can generate intense UV light for a variety of industrial applications. These LED light bars present unique thermal challenges due to their high power and compact environments. The CFD model was constructed based on 3-D geometry provided by Phoseon. This geometry was slightly simplified for improved numerical performance. All flow was driven by a 40x40x28 Sunon fan that could deliver 24 CFM at 0.0 inch H20 backpressure. The fan curve was directly integrated into the CFD model. The flow through the light box was restricted by an exit baffle with 25% of its cross-sectional area blocked. This flow restriction increased the internal pressure within the box and drove a portion of the air stream through the exit passages drilled into the box alongside the high power LED arrays. Aluminum was used for all heat sinks. The heat generating chips were modeled as ceramic. A thermal interface compound was used between the high power LED arrays and its massive aluminum heat sink. Results were delivered on time and validated the design intent with only a few design iterations.

Analysis of Air Flow and Thermal Behavior of the Sandhawk Outdoor Electronics Enclosure

The CFD model was generated from CAD geometry provided by the client.  An air enclosure was created around the system to allow convective heat transfer to the surroundings.  The back plane was assumed to be adiabatic and the front and side surfaces were set to the ambient far-field air temperature of 20 C. Power loads (Watts) were applied to the designated chips (marked with a stripe) and fan motor (2 W). The chips rests on a special conducting layer (1 W/m*C) which then is bonded to a large aluminum chunk.  The chips are modeled as a glass compound with limited conductivity. The internal fan was driven by fan curve with a peak flow of 42 CFM. 

Computational Fluid Dynamics (CFD) Analysis of Automated Test Equipment

Predictive Engineering conducted a broad range of computational fluid dynamics (CFD) analyses for a major manufacturer of automatic test equipment (ATE). This ATE equipment addresses a broad spectrum of the semiconductor industry's testing needs for the design, validation, and test of analog, digital, memory, mixed-signal, and wireless semiconductor devices. The lion's share of the CFD work was executed to drive the design of a novel, high-chip density circuit board layout. Predictive results were then compared to experimental mockups and eventual drove the design away from forced convection cooling to one that more heavily leverages heat pipe cooling and other advanced circuit board cooling technologies

Computational Fluid Dynamics (CFD) Analysis of Cable Assembly

Computational fluid dynamics (CFD) analysis was performed for a world leader in the design and manufacture of complete, turnkey cable assemblies for OEMs of ultrasound, surgical, and high speed data operations. Conjugate convective-conductive thermal fluids analysis was performed on a tightly integrated circuit board enclosed within a plastic case. Various cooling scenarios were investigated (forced cooling via a small embedded fan and natural convection) and chip junction temperatures predicted. Based on these CFD analyses, the circuit board chip density and power density (watt loading per chip) was optimized for long term thermal reliability.

CFD Pressure Drop Analysis through Bag House

A 2-D and later 3-D CFD model was built of complex flow path through a large bag-house structure.  The 2-D flow model was used for scoping work and then the final 3-D model captured the flow pattern from furnace gasses to fabric bag and final exit through scrubbing equipment. The predicted pressure drops due to passage way constrictions and filters were checked against prior experimental work and shown to be in good agreement.  Based on the CFD results, the client proceeded with the construction of this multi-million dollar pollution control system.

Thermal Management of Large Cart-Based Ultrasound System

This project went on for years at a major international manufacturer of ultrasound systems. The thermal analysis was based on pushing air over an array of printed circuit boards while baffling the inlets and outlets to keep overall system noise low. Thermally, the project was not overly difficult since the electrical engineers had provided power dissipation levels for the chips and power supplies.  The CFD model of the system assumed that the convective heat transfer from the chips and no thermal loss into the surround cabinet. Thermal results were validated against thermocouples and were found to be in tight agreement. Over the course of several years, dozens of models were constructed and validated. At our recommendation, the manufacturer brought this skill set in-house and we continued to collaborate with them to fine tune their CFD simulation process.

Cases Studies

Respirator Mask for Emergency Responders CFD Transient Air Flow Modeling - Predictive Engineering CFD Consulting Services

Respirator Modeling: Fit (LS-DYNA) and Function (CFD Transient Flow)

Engineering Safety

Respirator masks have historically been designed with lots of silicone rubber to slop over a range of faces. This works adequately for many facial sizes but not for all.

Thermal optimization of biological conditioning oven by CFD simulation

Thermal Conditioning Oven for Biological Samples

Modeling Details:

Figure 1 shows the starting point for the CFD simulation. The CAD geometry was de-featured and simplified for the model.

Air Handler

CFD Analysis of Roof-top Mounted Hospital Air Handler Analysis

Modeling Assumptions and Details: A CFD finite element model was built based on drawing and geometry information provided by the client.

CFD Simulation of Emergency Diesel Exhaust Entering Hospitals HVAC System - CFD Consulting Services

CFD Simulation of Possible Diesel Generator Exhaust Infiltration into HVAC System

The project required a fair amount of results interpretation since our client's final customer were eye doctors and even the chance that diesel exhaust and soot particles might enter their facility was completely off the table.

Thermal Analysis of Innovative LED Light Assembly

Thermal Analysis of Innovative LED Light Assembly

Predictive Engineering was contacted to execute a CFD simulation on an extremely tight timeline.

CFD and Stress Analysis of a Movable Deflection Wall in a Coastal Airport Environment

CFD and Stress Analysis of a Movable Deflection Wall in a Coastal Airport Environment

Introduction: The wall finite element analysis model was developed based on geometry provided by the client. The finite element (FE) model was built using mainly 4-node plate elements.

Large Manufacturing Facility HVAC Analysis

Large Manufacturing Facility HVAC Analysis

Before tackling the analysis of the complete facility, two sections of the building were analyzed to explore the most harsh summer and winter operating conditions.  These sections were chosen carefully to ensure that they represent the most challenging scen