影响环路热管可靠性及寿命的关键因素及作用机理研究

Loop heat pipe (LHP) is considered as the core component of the spacecraft thermal management system, and the realization of high reliability and long lifetime has become the core technology for its wider space applications. The heat leak of “evaporator-compensation chamber” coupling structure and the non-condensable gas (NCG) generated inside the LHP are the key factors affecting the reliability and lifetime. So far, little fundamental research has been carried out on this issue so that the mechanism of the effect of coupling heat leak and NCG on the thermal performance is still not clear. In this project, theoretical analysis and experimental study are adopted to investigate the changes in the steady-state thermal performance, startup and transient behaviors of a LHP that are caused by coupling heat leak and NCG. In the experiment, the required amount of NCG will be injected into the loop, and the distribution of the NCG in the LHP can be obtained by isotopic tracer technique and mass spectrum measurement. Through a series of fundamental tests, the effect of coupling heat leak on the steady-state performance, startup and transient behaviors will be obtained, and the effect of NCG inventory on the transient behaviors will also be obtained, from which the variation of the heat transfer mechanism in the LHP caused by coupling heat leak and NCG will be analyzed and revealed. Based on the experimental and mechanism analysis results, an improved LHP mathematical model considering the coupling heat leak and NCG effect will be established. The achievement of this project will not only reveal the mechanism of the changes on the thermal performance caused by the coupling heat leak and NCG but also provide theoretical basis for the development and applications of LHPs with high reliability and long lifetime.

作为航天器热控系统的核心部件，实现高可靠性和长寿命已经成为环路热管全面步入空间应用亟待突破的核心技术，而“蒸发器-储液器”耦合漏热和不凝气体是影响其可靠性和寿命的关键因素。目前，国际上针对该问题的基础性研究工作开展较少且缺乏系统性，对耦合漏热及不凝气体引起的传热变化机理认识不足。项目拟通过实验研究和理论分析，从稳态、启动和瞬态三个层面，对耦合漏热和不凝气体引起的环路热管热性能变化问题进行系统深入的研究。实验采用定量充装不凝气体的方法，通过同位素示踪技术及气体成分的质谱分析，获得不凝气体的分布及汇集规律；通过可视化实验研究耦合漏热对环路热管稳态、瞬态、启动热特性的影响规律，以及不凝气体对环路热管瞬态性能的影响规律，全面揭示耦合漏热和不凝气体影响环路热管传热特性的机理；在此基础上建立耦合漏热和不凝气体影响环路热管性能的理论模型，为我国航天级高可靠性长寿命环路热管的研制提供科学依据。

本项目围绕我国航天级环路热管的高可靠性与长寿命问题，深入系统地研究了“蒸发器-储液器”耦合漏热和不凝气体影响环路热管工作性能的规律和机理。实验采用定量充装不凝气体的方法，从稳态、启动两个方面，对不凝气体引起的环路热管热性能变化问题进行了系统深入的研究与分析，获得了不凝气体对环路热管性能的影响规律，并在此基础上建立了不凝气体影响环路热管性能的理论模型；通过可视化实验研究了耦合漏热对环路热管稳态、瞬态、启动热特性的影响规律，全面揭示了耦合漏热影响环路热管传热特性的机理；本项目得到了一系列的实验数据和数学模型，进一步深化了对环路热管系统运行机理的认识，为我国航天级高可靠性长寿命环路热管的研制提供了科学依据。