A thermal model for calculating thermal resistance of eccentric heat source on rectangular plate with convective cooling existing at upper and lower surfaces

Heat sources on rectangular plate with cooling at both upper and lower surfaces are common in electronic devices. A thermal model for calculating thermal resistance of eccentric heat source on plate with convective cooling at upper and lower surface is presented in this paper. The model was applied for calculating thermal resistance of a plate at three groups of boundary conditions. Simulations for calculating thermal resistance at the same boundary conditions were also done by software COMSOL. The comparison between the thermal resistances calculated by the presented model and the ones obtained by simulations showed that the proposed model is suitable for thermal resistance calculation of rectangular plate with cooling at both surfaces. The presented model can calculate the plate thermal resistance at following boundary conditions with high accuracy : I) Free convection at both surfaces; II) Free convection at upper surface and forced convection at lower surface.