Sample FEMLAB Work

Here I present several FEMLAB analyses.  The first is a three dimensional heat conduction analysis of a multiprocessor server unit.  The second is a simple conjugate fluid flow and heat transfer analysis of a heat exchanger.  The third is a simple stress analysis of a part that I created in Inventor and imported for stress analysis during the design embodiment.

• Multi-Processor Server Conduction Analysis
• Conjugate Flow and Convection Analysis
• Stress Analysis

Multi-Processor Server Conduction Analysis

This analysis was part of a case study I performed as part of a team for my graduate course in thermal packaging of electronics.  The full report is avaliable here.  This analysis was performed using conduction only, the heat transfer to the surrounding air was computed using convection coefficeints computed from an thermal-fluid analysis we performed in FLUENT.  In this problem the geometry is symetrical and as such only 1/8 of the geometry is used.  The geometry, mesh, and results are shown below.

Geometry

The geometry was simplified slightly to include only 1/8 geomery and the removal of the solder ball grid below the chips.  The thin interface materials of the thermal grease used for chip contacts was modeled as a contact resistance to avoid very small geometry and the associated memory and computational overhead.

Mesh

The mesh density here was tricky becuase of the high aspect ratio of the geometry, the detail of the individual chips, and the overall size of the geometry.  This meant that the mesh needed to be refined in the center, while getting very coarse at the edges to avoid having too large a system to solve.

Results

The results show the temperature of the surface of the geometry, and the isosurfaces, levels of equal temperature to show the temperature distribution within the server unit.

Conjugate Flow and Convection Analysis

This analysis was a simple investigation into how FEMLAB links is physics.  In this case the fluid flow is first determined using the incompressible Navier-Stokes solver, and then the energy equation is solved using u and v as computed by the first step, assuming forced convection.  The resulting plot shows the flow vectors, temeprature field, and heat flux contours:

Stress Analysis

For this analysis I first imported the geometry I had created in Inventor as an IGES file into FEMLAB.  I then meshed the geometry and applied the appropriate loading and constraint boundary conditions.  The results and mesh are plotted below:

Mesh

The mesh was defined with extra detail in the corners and other areas of stress concentration and higher gradients for an accurate analysis.

Results

The results plot shows the magnified displacement of the part as well as the Von Mises Stress.