以液氮为降温介质的低温喷雾冷却技术，是深冷工艺设备的关键技术之一，通过-196℃的极低温介质实现快速相变制冷，使材料在深冷环境中实现性能调质。为探究影响液氮喷雾换热性能的关键因素，设计并搭建了液氮喷雾换热试验平台，系统研究了喷雾高度、喷雾流量、喷嘴直径及喷嘴数量对换热性能的影响。试验结果表明，喷雾高度控制在90.3 mm时可在120 W/cm2热流密度下获得18.3 W/cm2·K的最大换热系数；在流量达到0.0157 kg/s 时，表面过热度在160 W/cm2条件下保持低于16 K；喷嘴直径方面，1.0 mm喷口直径的喷嘴表现最佳，120 W/cm2工况下换热系数约为14 W/cm2·K；三喷嘴布置在80 W/cm2热流密度下实现约20 W/cm2·K的峰值换热系数，并在高热负荷工况下保持过热度稳定。结果表明与传统单喷嘴或多喷嘴布局相比，三喷嘴工况在液滴覆盖均匀性和蒸发持续性方面形成更优平衡，喷雾高度略低于临界高度、适中粒径、较高质量流量可协同提升换热系数并抑制高热通量下的过热度。

Cryogenic spray cooling technology using liquid nitrogen as the cooling medium represents one of the key techniques in deep cryogenic processing equipment. By employing an extremely low-temperature medium at –196 °C, rapid phase-change refrigeration is achieved, enabling material property adjustment in a cryogenic environment. To investigate the critical factors influencing the heat transfer performance of liquid nitrogen spray cooling, an experimental platform was designed and constructed, and a systematic study was carried out on the effects of spray height, mass flow rate, nozzle diameter, and nozzle number. Experimental results show that when the spray height is controlled at 90.3 mm, a maximum heat transfer coefficient of 18.3W/cm2·K can be obtained under a heat flux density of 120 W/cm2. At a mass flow rate of 0.0157 kg/s, the surface superheat remained below 16 K at a heat flux density of 160 W/cm2. Regarding nozzle diameter, the 1.0 mm orifice performed best, achieving a heat transfer coefficient of approximately 14 W/cm2·K at 120 W/cm2. In terms of nozzle arrangement, the use of three nozzles produced a peak heat transfer coefficient of about 20 W/cm2·K at 80 W/cm2, while maintaining stable surface superheat under high heat flux conditions. These findings indicate that, compared with conventional single or multi-nozzle configurations, the three-nozzle arrangement achieves a superior balance in droplet coverage uniformity and sustained evaporation. Moreover, maintaining a spray height slightly below the critical height, using moderate droplet sizes, and operating at relatively high mass flow rates can synergistically enhance the heat transfer coefficient while suppressing surface superheating under high thermal loads.

山西省重点研发计划项目（202202150401011）