A multi level modeling approach with boundary condition import for system, sub-system or board level thermal characterization

Application of multi level approach with exact boundary condition import for performing accurate and time efficient CFD design calculations for a populated system cooled by forced air flow is studied. The approach involves a coarse system level model for determining appropriate boundary condition profiles for sub-systems, and a detailed sub-system level model that utilizes the boundary condition determined from the system level model. The advantages of the proposed approach are quantified by comparison with a detailed full system model. The size of the models in terms of mesh count and the accuracy of predicted component temperatures were the quantities compared. The acceptable errors of the multi level modeling approach with profile boundary conditions were in contrast with the multi-level modeling in which the boundary conditions were uniform nominal values or mean values of velocities and temperatures.