目的 揭示不同低气压环境对液氮喷雾冷却性能的影响机制。方法 采用数值仿真的方法对低压环境下的液氮喷雾冷却性能进行研究,研究低压下液氮喷雾冷却的演化机理,分析15~101 kPa环境压强下液氮喷雾冷却过程,对比分析低压下和常压下液氮喷雾颗粒的运动轨迹以及温度场,探究低压环境对液氮喷雾冷却的冷却性能的影响,以及环境压强变化对壁面温度、壁面温度不均匀性和壁面平均换热系数的影响。结果及结论 建立了低压下喷雾冷却的数值计算模型,模拟了不同环境压强下的液氮喷雾冷却过程。结果表明,低压环境下液氮在加热表面的沸腾更加剧烈,低压环境对液氮喷雾冷却壁面温度的影响受到多种参数综合作用的影响,随着环境压强的降低,冷却性能先变差,随后逐渐变好。随着环境压强降低,壁面温度不均匀程度增大,平均换热系数降低。
Abstract
The work aims to investigate the effect mechanisms of different low pressure environments on the cooling performance of liquid nitrogen spray. The numerical simulation method was employed to study the cooling performance of liquid nitrogen spray in low pressure environments, investigate the evolution mechanisms of liquid nitrogen spray cooling at low pressure and analyze the cooling process within the 15 kPa to 101 kPa environment pressure. The trajectory and temperature field of liquid nitrogen spray particles under low pressure and normal pressure were compared and analyzed, and the effect of low pressure environment on the cooling performance of liquid nitrogen spray cooling as well as the effect of environment pressure change on wall temperature, wall temperature inhomogeneity and average wall heat transfer coefficient was explored. A numerical model for spray cooling under low pressure conditions is developed to simulate the liquid nitrogen spray cooling process across different environment pressures. The results demonstrate that boiling phenomena at the liquid nitrogen heating surface intensify under low pressure environments. The impact of environment pressure on wall temperature exhibits complex parameter-dependent characteristics, where cooling performance initially deteriorates and subsequently improves with the decreasing environment pressure. With the decrease of ambient pressure, the non-uniformity of wall temperature increases and the average heat transfer coefficient decreases.
关键词
液氮喷雾冷却 /
数值模拟 /
低压环境 /
温度不均匀性 /
冷却性能
Key words
liquid nitrogen spray cooling /
numerical simulation /
low pressure environment /
temperature non-uniformity /
cooling performance
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基金
国家自然科学基金青年科学基金（52106124）
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