A Multigrid Based Multi-Scale Thermal Analysis Approach for Conjugate Problems Involving Discrete Heating

A multi-grid enhanced multi-scale analysis approach is presented for conjugate heat transfer systems with a large range of length scales of interest. The multi-scale analysis involves a sequential two-step “zoom-in” approach to resolve both the large length scale associated with the enclosure and the smaller length scale associated with fine spatial structures of heat sources. Significant computation time saving with this approach is realized compared to conventional computational fluid dynamics/computational heat transfer (CFD/CHT) modeling. Performance of the multi-scale approach is further enhanced by integrating the multi-grid technique as the CFD/CHT solver. Implementation of the enhanced approach is demonstrated for the thermal analysis of an array of discrete heat sources cooled by mixed and forced convection. It is found that the multi-grid enhanced multi-scale thermal analysis reduces simulation run time by 90% compared to multi-grid with SIMPLER. And the temperatures computed from the approach are in good agreement with measurements, deviate by no more than 8% from measurements.