Transient Cooling of Millisecond-Pulsed Heat Sources by a Jet Impingement Heat Sink with Metallic Phase Change Material

Thermal management has become a critical issue for the reliable operation of electronic devices, especially for pulsed heat sources with high heat flux. The intense temperature rise in a short period puts forward high requirements on thermal management. In this work, a heat sink combining the confined jet impingement with metallic phase change material (PCM) is proposed for the thermal management of millisecond-pulsed heat sources. A transient model is established to simulate the conjugated heat transfer. The heat transfer characteristics of a jet impingement heat sink and the temperature responses under millisecond heat pulses are obtained, and the effects of jet structure and metallic PCM thickness on the cooling performance are analyzed. Results show that the jet impingement with a jet diameter of 2 mm and an impingement height of 2 mm can achieve effective cooling on a 3 × 3.5 mm² heat source, and the surface temperature is 62.2 °C for a constant power density (150 W/cm²). Under the millisecond heat pulses with a peak power density of 600 W/cm² and a duty cycle of 0.25, the temperature on the heating surface fluctuates in the same period with the heat pulses, and the maximum temperature reaches 66.9 °C for a heat sink without metallic PCM. An appropriate PCM thickness should be smaller than 0.1 mm so that the phase change can be cycled within heat pulse intervals, and the maximum temperature can be maintained around the phase change temperature (61.5 °C).