微重力热泵的多元气液两相流动与相变传热强化机理

Aerospace vapor compression heat pump control system can significantly reduce theradiator area. It can take advantage of the sunny side for heat radiation and has high adjustment ability, which is considered to be the best choice for spacecraft thermal control system used for the development of the moon and other deep space exploration. Aerospace heat pump needs to be addressed in microgravity adaptability. The refrigeration compressor with oil pool and separator on the ground environment will be unable to separate refrigerant and lubricant in microgravity environment, and the lubricant will pour into the compression chamber and cause compression deterioration. The project proposes the solution of completely mixing the refrigerant and lubricant for microgravity heat pump, without oil pool and separator. The project will study on the flow and phase change heat transfer enhancement mechanism of multivariate gas-liquid two phase with refrigerant and lubricant thoroughly mixed for the microgravity heat pump. It aims at revealing the correlation mechanism of compressor structure and the phase distribution of refrigerant/lubricant gas-liquid two-phase flow and the influence mechanism of lubrication, sealing, cooling and irreversible loss for the compressor. The project will clarify the correlation mechanism of evaporator/condenser structures and the lubricant flow, sedimentation and phase distribution and the influence mechanism of phase change heat transfer. The correlation mechanism of evaporator/condenser structures and transformation kinetics and heat transfer of evaporation and condensation for refrigerant will also be explored. The project will provide calculation and analysis methods and theoretical basis for the development of aerospace heat pumps with high performance and reliability.

航天蒸汽压缩热泵热控系统具有能够大幅降低辐射散热器面积、可利用向阳面散热和调节能力强等优点，被认为是月球开发、深空探测等航天器热控系统的最佳选择。航天热泵需要解决微重力适应性问题，特别是地面上设油池和油分的制冷压缩机在微重力下会出现制冷剂和润滑油无法分离，润滑油会大量进入压缩室中造成压缩恶化的问题。本项目提出采用制冷剂和润滑油完全混合，不设油池和油分的微重力热泵解决方案，针对制冷剂和润滑油完全混合的微重力热泵中的多元气液两相流动与相变传热强化机理展开研究，旨在揭示压缩机结构与制冷剂/润滑油的气液两相流的相分布关联机理及其对压缩机润滑、密封、冷却和不可逆损失的影响机理；阐明微重力下蒸发/冷凝器结构与润滑油流动、沉积和相分布的关联机制及其对相变传热的影响机理；探悉微重力下蒸发冷凝器结构与制冷剂蒸发冷凝相变动力学及其传热的关联机制，为研制高性能高可靠性的航天热泵提供计算分析方法和理论依据。

本项目针对制冷剂和润滑油完全混合的微重力热泵中的多元气液两相流动与相变传热强化机理展开研究，旨在揭示压缩机结构与制冷剂/润滑油的气液两相流的相分布关联机理及其对压缩机润滑、密封、冷却和不可逆损失的影响机理。阐明微重力下蒸发器和冷凝器结构与润滑油流动、沉积和相分布的关联机制及其对相变传热的影响机理。探悉微重力下蒸发冷凝器结构与制冷剂蒸发冷凝相变动力学及其传热的关联机制。在弥补当前微重力理论研究缺失的同时，也为研制高性能高可靠性的航天热泵提供计算分析方法和理论依据。从2020年初到2022年末这三年的时间，我们开展了大量的理论和实验研究工作：研究了微重力下制冷剂和润滑油混合对压缩机内油气分离的影响机理，通过对Aspen滚动转子压缩机改造并进行重力无关实验验证；建立了滚动转子压缩机的压缩腔内流动模型，研究了重力对压缩机工作过程的影响，确定了重力对制冷剂和润滑油混合物在压缩腔内的相分布影响以及润滑油对压缩机工作状态以及润滑的影响规律；通过数值模拟建立了模型，得到了微重力下蒸发器和冷凝器结构与润滑油流动、沉积和相分布的关联机制及其对相变传热的影响机理；研究了重力对制冷剂-润滑油混合物在蒸发器内相变的速度场、压力场、温度场和相分布的影响，分析了不同重力条件下润滑油的流动、沉积和分布对相变传热的影响，探究润滑油的存在对蒸发器换热性能的影响；开展了蒸气压缩热泵系统的地面模拟试验，实验获得了微重力环境下热泵系统温度与压力的变化规律及换热器的换热性能。在国内外重要的学术期刊发表论文6篇，其中SCI/EI检索期刊论文5篇，授权实用新型专利2项。培养/协助培养人才取得硕士学位共3人。该课题的研究对于拓展微重力两相流动传热研究范围，提高航天蒸气压缩热泵的性能和可靠性具有重要的学术意义和工程应用价值。