Performance of a guided plate heat sink at high altitude

Abstract

In the present study, the thermal performance of an enhanced air-cooled heat sink system, comprising of a parallel plate-fin heat sink (PPFHS) with a guide plate installed to alter the bypass flow, was analyzed for fan-driven convection conditions at various altitudes from sea level to 12,000 m. Numerical simulations were carried out using ANSYS Fluent 16.0 with the κ-ω SST turbulence model to analyze the airflow and assess the thermal performance. After validation by experimental data in the literature, numerical results of the flow and temperature fields were obtained for different environmental pressures, several fan speeds and PPFHS design parameters. The measured characteristic fan curves at different altitudes show that the fan delivers approximately the same volume flow rate at different altitudes. For high-altitude operation, using the PPFHS only configuration could lead to electronic failure due to the larger temperature increase compared to using the PPFHS/guide plate configuration. For both configurations, the optimum fin number ranges between 20 and 32, which depends on the environmental pressure and fan speed. Improper use of highly dense PPFHS may lead to inadequate electronic cooling and will add extra weight for high-altitude operation. The optimal fin thickness depends on the fan speed, and the minimum thermal resistance occurs with low fin thickness at the lower fan speeds. Weight optimization procedures were conducted to obtain a considerable decrease in the PPFHS/guide plate weight and to achieve optimal thermal resistance at lower fan speeds.