Week 9 - PCB Thermal Simulation

JORGE LOZANO

Electronic Cooling Simulations using ANSYS ICEPAK

PCB THERMAL SIMULATION

A PCB board, library files, and traces are imported to create the model. The model is first solved for conduction only, without the components and then solved using the actual components with forced convection.

Process

Given this geometry, the first step is to drag into the workspace the Icepak module, and import the CAD file, deleting the bolts, fillets, washers unwanted. Inspection of the initial CAD file is critical to define the following steps and process taken place.

By selecting a simple or detail import configuration and determining a 3 mm gap the final geometry pre-processed could end up like one of the following options. Which for the left side case a clean up must be performed to define the case set-up.

The heat shrinks and PCB Board are obtained by defining the ICEPAK components.

By defining the trace layer parameters and thermal specification as recommended, as well as the materials and thicknesses of the layers, a conduction (pure) and forced convection simulation could be performed as follows.

The thicknesses and materials could be modified to determine a well and real-like thermal simulation of the case involved and including the grid density count values for both axis.

By importing the files at the beginning the board layer and via information is imported as well, and by viewing and determining before the layers’ lengths, the following image is containing a complete visualization.

Each layer can be obtained and analyzed separately as well as seeing its properties.

Due to the inclinations of the simulations to perform, several view options are possible by using the ICEPAK software which the following images is showing:

Within the electrical, structural, and thermal analysis to perform, a metal fraction contour can be obtained along with the other electronic components.

Processing

ICEPAK meshes are obtained for this specific simulation, not meshing every single component, but as a whole, by selecting a particular mesh element a specific quantity of elements can be requested in an initial mesh.

Always viewing and modifying the meshing parameters from the Skewness quality control as a general criterion.

Processing

By processing a pure thermal conduction simulation all components achieve a 150 C, not being very thermally possible to function at those temperatures.

The temperature contour shows a constant dissipation increasing, not significantly at the processor, where the greater heat shrink is located.

The heat generation shows similar values at all directions and responding to the current and power generated by the import conditions applied.

Forced Convection

By applying a forced convection from the minimum x opening to the maximum x opening at a 1.5 m/s velocity of air, the following results appear, first with the residuals at 200 iterations, with 1/2 million elements.

The following specific temperatures for important elements are monitored to evaluate the effectiveness of the velocity and position of the fan or opening reaching a maximum of 23.5 C.

A more thermal comfort of all components and specific heat component generation is seen as the cooling works and the performance of the thermal electronic components are well maintained with this configurations and conditions.

The heat generation shows similar values at all directions and responding to the current and power generated by the import conditions applied, seeing the same values as the conductive thermal simulation.