Experimental Investigation of Enhanced Heat Sinks for Hybrid Electric Aircraft

Abstract Controlling the temperature of onboard battery systems is a key thermal management challenge for hybrid electric aircrafts. Initially, a standard plate-fin heat sink was used in an innovative approach to dissipate heat generated by battery cells in electric vehicles. However, based on an analysis of a kW-scale hybrid electric aircraft, two heat sinks were specifically optimized for the aircraft’s application: pin-fin and micro-structured heat sinks. This paper compares the performance of these optimized heat sinks with that of the original plate-fin heat sink. A custom-designed box was created to direct airflow into the heat sinks, modeled in accordance with the specifications used in CFD analysis. Testing was conducted across two different airflow rate ranges. The results showed that the optimized heat sinks outperform the original in terms of thermal performance and weight. Experimental results indicated a more substantial performance enhancement with the pin-fin heat sink than what the simulations predicted. Significant improvements were observed using optimized pin-fin heat sink at higher airflow rates and greater source powers. At lower airflow rates, the microstructured heat sink, produced through advanced micromachining, proved to be the optimal choice, delivering the best performance with the lightest weight.