微纳米表面真空闪蒸喷雾冷却机理研究

Vacuum flash spray cooling technology with the rapid evaporation of the working fluid can absorb large quantities of latent heat of vaporization. Comparing with the traditional way of spray cooling, it has higher heat exchange capacity and less working fluid demand, thus has a broad application in the temperature control of the spacecraft equipment cabin and in the cooling of electronic components. Scientific issues of the project include the mechanism of droplet flash evaporation and the diffusion law, the mechanism of film flash evaporation on macro-nano structured surfaces and bubble characteristics, developing macroscale mathematical model of the vacuum flash spray cooling on macro-nano structured surfaces. In the current project, visualization research and numerical simulation will be expanded on droplet flash evaporation, film flash evaporation on macro-nano structured surfaces and bubble formation & development. Models of droplet flash evaporation and film flash evaporation on macro-nano structured surfaces are to be proposed in this project. The goals of the project are to investigate the interaction mechanism between different droplets during flash evaporation and the evolution characteristics of the bubble within the film and its effect on the heat transfer. And then the law of heat & mass transfer during the process of vacuum flash spray cooling on macro-nano structured surfaces can be obtained. Expected results can provide a theoretical basis for improving the vacuum flash spray cooling technology, and it is also important for the development of highly efficient thermal protection technology.

真空闪蒸喷雾冷却技术凭借冷却工质的快速、高度汽化吸收大量潜热，具有比传统喷雾冷却方式更强的换热能力和更少的工质需求，在空间飞行器设备舱内的环境温度调控和电子元器件冷却等方面具有广阔的应用空间。本项目的科学问题是雾化液滴的闪蒸机理和扩散规律、微纳米表面液膜的闪蒸机理和气泡特性、微纳米表面真空闪蒸喷雾冷却的宏观尺度数理模型。项目拟对液滴的闪蒸、微纳米表面液膜的闪蒸、气泡的形成和发展规律开展可视化实验研究和数值模拟研究，建立液滴闪蒸模型和微纳米表面液膜的闪蒸模型，揭示耦合闪蒸效应的雾化液滴之间相互作用机理和液膜内部气泡的演变特性及其对液膜流动换热的影响，获得真空闪蒸喷雾冷却在喷雾空间和微纳米表面的热质传递规律。预期研究成果可为改进真空闪蒸喷雾冷却技术提供理论依据，对发展高效热防护技术也有重要意义。

真空闪蒸喷雾冷却技术凭借冷却工质的快速、高度汽化吸收大量潜热，具有比传统喷雾冷却方式更强的换热能力和更少的工质需求，在空间飞行器设备舱内的环境温度调控和电子元器件冷却等方面具有广阔的应用空间。本项目围绕真空闪蒸喷雾冷却技术，开展了液滴闪蒸的理论研究，建立了液滴闪蒸的数学模型，并基于实验结果对模型进行了验证。计算并总结了液滴直径、环境温度和压力、液滴组分浓度等对液滴闪蒸结冰相变特性的影响规律，获得了真空环境液滴的存在时间及其主要影响因素。搭建了真空闪蒸喷雾冷却实验系统。开展了液膜闪蒸的理论研究和实验研究，建立了液膜闪蒸的数学模型，并基于实验结果对模型进行了验证和计算结果的深入分析。制作了微纳米结构表面，并开展了真空喷雾过程液滴参数变化的实验研究，获得了不同压力环境下雾化液滴的尺寸变化特性。发展了真空闪蒸喷雾冷却的计算方法，并开展了真空闪蒸喷雾冷却的三维数值模拟，获得了工质流量、喷雾压力和环境压力、气流出口位置等对真空闪蒸喷雾冷却性能参数的影响规律。建立了宏观真空闪蒸喷雾冷却的数学模型，该模型适用于包括微纳米表面在内的几乎所有发热表面。研究并提出了空间飞行器设备舱体的压力和温度的控制方法，计算分析了典型工况条件，如喷雾流量、气流出口直径和环境压力等对设备舱内压力和温度，发热表面温度的控制规律。研究成果可为改进真空闪蒸喷雾冷却技术提供理论依据，对发展高效热防护技术也有重要意义。