03. Electronics Packaging and Thermal Management

The increasing heat dissipation of integrated circuits necessitates efficient thermal management (TM) systems for their reliable operation. This study investigates the thermal performance of a solid-solid phase change material (SSPCM) integrated pin-fin heat sink for remote sensing instruments in avionics. Three different SSPCM configurations, with NPG (an organic SSPCM), X55 (a commercial SSPCM), and a mixture of NPG-X55 (with 50%-50% by wt.), are employed to absorb thermal energy. A square pin-fin heat sink made of aluminum with dimensions 35 mm x 65 mm x 35 mm is used to augment the heat transfer and act as a thermal conductivity enhancer (TCE). An electrical heater placed at the heat sink base serves as a surrogate for the heat dissipation of electronic sensors. Numerical simulations were performed at a constant heat input of 4 W, 6 W, and 10 W. A parametric analysis was conducted to evaluate the influence of the PCM volume fraction, which is defined as the ratio of PCM volume to the total empty volume of the heat sink void volume excluding the fins) on the thermal performance of the pin-fin heat sink. The thermal performance is assessed through enhancement ratios and safe operational time (SOT) at three critical set point temperatures (SPTs). The results demonstrate the effectiveness of SSPCMs in extending the safe operation duration of the system compared to a baseline heat sink without PCM. Additionally, the influence of PCM volume fraction on thermal performance is analyzed. The numerical results were validated through experimental data, ensuring the reliability of the TM system for remote-sensing instruments in avionics.