关键词: 低环境压力, 微通道热沉, 喷雾冷却, 入口过热度, 换热性能

Abstract: With the rapid advancement of aviation technology, the airborne electronic devices have been increasingly integrated, making traditional single-phase cooling technologies insufficient to meet the increasingly demanding heat dissipation requirements. To address this, this study proposes a new and efficient cooling technology that couples microchannel heat sinks with a spray cooling module. A high-power open flash evaporation experimental system simulating high-altitude low-pressure environments was built to explore the effects of the inlet superheat of the hot-side fluid and the type of working fluid on heat transfer performance. The study results indicate that reducing environmental pressure and increasing the inlet temperature of the hot-side fluid can both increase the inlet superheat of the hot-side fluid, thereby enhancing heat transfer and improving working fluid utilization. However, the mechanisms of these effects differ. The physical properties of the working fluid are crucial factors affecting flow and heat transfer characteristics. When water is used as the hot-side fluid, the heat transfer rate can reach up to 3326 W, with a vaporization ratio of 30.84% and a power consumption ratio of 456. In contrast, when 65# coolant is used as the hot-side fluid, the heat transfer performance significantly decreases, with the heat transfer rate and vaporization ratio both reducing by about 18% compared to water, and the power consumption ratio reducing by around 53%. The main reason for this is that 65# coolant has a higher dynamic viscosity and a lower thermal conductivity, leading to deteriorated flow and heat transfer characteristics. This study could provide a theoretical basis for the design and performance optimization of efficient thermal management systems for high-power airborne electronic devices.

Key words: low environmental pressure, microchannel heat sink, spray cooling, inlet superheat, heat transfer characteristic