More CFD Projects
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A Summary of Additional CFdesign Projects
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 dynamics (CFD) 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.
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