Transient Cooling of Millisecond-Pulsed Heat Sources by a Jet Impingement Heat Sink with Metallic Phase Change Material  
[PERSON]  
1 State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China 1  
[PERSON]  
1 State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China 1  
[PERSON]  
1 State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China 1
\(d\), depth of the nozzle \(l\), jet spacing \(S\), etc. ), jet velocity, jet direction, physical properties of cooling medium, surface structure to be cooled, etc. For single-phase confined jet impingement, many studies have been performed on the heat transfer characteristics of single jet and multiple jets [4; 5; 6; 7; 8; 9; 10]. Generally speaking, the cooling performance of single-phase jet impingement improves with the increase in jet \(Re\) number and the decrease in \(d\). When \(H/d\) is in the range of \(1<H/d<5\), \(H\) has no obvious effects on the heat transfer coefficient; when \(H/d\) is too large, the heat transfer performance tends to degrade. With the same pump power and flow rate, the average heat transfer coefficient decreases with the increase in \(S/d\), while the heat transfer coefficient of the stagnation point changes little. For devices with transient power fluctuations, phase change materials (PCMs) can be used as an auxiliary temperature control method [11; 12; 13]. During the thermal design process, the corresponding active cooling system can be designed in the light of the basic heat load of the device, and PCMs can be equipped to prevent the device from overheating during the transient power fluctuation. Without the phase change temperature control unit, the cooling system needs to be designed according to the highest heat load, increasing its cost and complexity. In recent years, metallic PCMs have been paid wide attention in the field of thermal management [14; 15; 16; 17; 18]. Metallic PCMs have high thermal conductivity, low volume change rate, and no phase separation, phase stratification or evaporation, which provides an effective solution for thermal management. [PERSON] et al. [19] studied the performance of plate-fin and pin-fin heat sinks combining a metallic PCM for intermittent electronic equipment. The PCM was a Wood alloy (50 Bi/27 Pb/13 Sn/10 Cd, melting temperature 70 \({}^{\circ}\)C). It was found that PCM could provide additional heat capacity and reduce the size of thermal management equipment and energy consumption compared to conventional heat sinks. [PERSON] et al. [20] integrated metallic PCM into an IGBT molybdenum plate and analyzed the effects of incorporating PCM on normal working devices by the finite method. The results showed that the heat pulse handling ability of the devices incorporated with metallic PCM was improved significantly. PCM integrated into the heat sink [21; 22; 23] can serve as a thermal buffer for longer power surges due to the larger volumes of PCM involved [24], while the thermal contact resistance between electronic devices and heat sinks has still not been solved. Another method is to embed the PCM into a substrate [25; 26] or the interface between a heat sink and an electronics package, which has limited buffer ability due to the small acceptable PCM volumes but a favorable thermal contact performance [27; 28]. In this paper, the thermal performance of a jet impingement heat sink with metallic phase change material (PCM) is investigated 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 the jet impingement heat sink and the temperature responses under millisecond heat pulses are obtained, and the effects of jet structure and PCM thickness on the cooling performance are analyzed.