超高速涡轮泵机械密封副材料摩擦学特性与慢渗机制研究

Mechanical face seals are one of key components in turbopumps for missile servo systems. As a key components of super-high speed turbopump, two kinds of problems, the malfunction due to the severe end face wear in super-high speed and high temperature conditions and the percolation under storage services with liquid pressure, lead to the fluid leakage. This will cause the malfunction of servo systems and the flying accident of the missile or the space launch vehicle. Thus, this project focuses on the investigation of the tribological properties of the mechanical face seals for super-high speed turbopumps and the mechanism of percolation under storage services with high liquid pressure. (1) The tribological properties of the seal pair materials will be studied. The correlation intrinsic among the tribological, mechanical and thermal properties of the seal pair materials in the special conditions will be disclosed. (2) The lubrication state evolution mechanism and law in the seal interface under the high temperature conditions and the dynamic characteristics of under the super-high speed and strong disturbance conditions will be investigated. The dynamic characteristic of the mechanical seals will be disclosed. (3) The end face film evolution law of the mechanical seals in flying conditions will be studied and the film formulation properties will be disclosed. (4)The influence factor of the percolation in the seal interface for the storage service with high pressure will be analyzed. The percolation mechanism will be disclosed and the control approach will be proposed. The research results will lay theoretical foundation and technical supports for improving the reliability of the super-high speed turbopump mechanical seals.

机械密封是导弹伺服系统涡轮泵的关键基础部件。作为超高速涡轮泵的关键部件，存在超高速高温工况下密封端面异常磨损失效和带压贮存状态界面慢渗问题，容易引起介质泄漏，导致伺服系统失效，而造成导弹或航天运载器飞行事故。为此，该项目拟开展超高速涡轮泵机械密封的摩擦学特性和带压贮存状态的慢渗机制研究，主要研究内容及创新：(1)研究密封副材料特性，揭示特殊工况下密封副材料摩擦学特性与其力学、热学特性的关联本质；(2)研究高温强干扰下密封界面润滑状态演变规律，并揭示其密封动态特性；(3)研究飞行工况下机械密封端面液膜演变规律，并揭示其成膜特性；(4)研究带压贮存密封界面慢渗影响因素，揭示慢渗机理并提出控制方法。项目研究成果可为提高超高速涡轮泵机械密封的可靠性提供理论依据和技术支撑。

机械密封是伺服系统涡轮泵的关键基础部件。作为超高速涡轮泵的关键部件，存在超高速高温工况和强干扰条件下密封端面异常磨损失效和长期带压贮存状态介质慢渗的问题，容易引起介质过量泄漏，导致伺服系统过早失效，进而造成导弹或航天运载器飞行事故。针对上述问题，本项目围绕涡轮泵机械密封配副摩擦磨损规律及材料选配方法、强干扰下超高速高温机械密封润滑成膜及动态特性、长期带压贮存条件下密封界面慢渗机理及控制方法等三个关键科学问题开展系统的数值模拟和试验研究工作。在密封副摩擦磨损及材料选配研究方面，通过基于标准摩擦磨损试验机的摩擦副摩擦磨损机理试验、拟实工况密封副摩擦学特性测试试验和整机氦吹工位耐磨性考核实验，阐明了不同工况和润滑状态下浸渍石墨/纯碳石墨与高温合金配副的摩擦磨损机理，基于高耐磨、低摩擦目标提出了涡轮泵机械密封副材料选配方法，并经整机氦吹工位试验验证有效。在机械密封润滑成膜及动态特性研究方面，建立了考虑柔性转子振摆、密封端面接触和热力变形等多因素耦合下超高速高温机械密封稳动态特性数值预测模型，阐明了涡轮泵机械密封端面液膜演变规律及成膜特性，揭示了强干扰条件下机械密封的动态特性行为，完善了实机工况下涡轮泵机械密封的设计方法。在机械密封慢渗机理及控制方法研究方面，基于多孔介质理论和双高斯分层理论建立了涡轮泵机械密封的界面慢渗预测模型，揭示了长期带压贮存条件下密封介质的慢渗机理，指出因氦吹试验造成的端面粗糙度和平面度改变、镶嵌石墨环残余应力导致的端面变形、石墨环在长期红油浸泡下的浸渍物析出导致的粗糙度改变是造成密封界面慢渗的主要原因，提出了通过合理设计镶嵌工艺参数和镶嵌结合面开设倒角、空刀槽的结构策略以延缓界面慢渗的控制方法。本项目的研究成果可为提高涡轮泵工作可靠性、降低其贮存维护工作量提供理论依据和技术支撑。