中文摘要：

针对自主研制的高压气动比例减压阀出现的结冰问题，结合数学仿真和流场计算进行了深入分析。结冰出现在先导阀中间腔而非温度最低的主阀排气腔说明温度并非导致结冰的唯一因素。建立了减压阀的数学模型，计算得出先导阀节流口面积比与先导阀中间腔压力以及温度的关系曲线，并得出使用2级和3级气源时先导阀中间腔结露的临界面积比分别为1.70和1.22。仿真结果表明，通过减小先导阀节流口面积比可以提高先导阀中间腔温度从而减少结冰的可能性。建立了先导阀的网格模型，用Fluent计算出阀内的流场分布，压力流场分布与理论计算符合得较好；速度流场及气流流线图表明出现结冰与气流受阀内结构阻挡有关，通过合理设计流道可有效避免结冰。

英文摘要：

In this article, the critical issue of icing in high pressure pneumatic relief valves is analyzed with mathematical simulation and flow field calculation. The fact that ice is found in the central cavity of the pilot valve rather than in the exhaust cavity of the main valve with much lower temperature indicats that temperature is not the only factor which causes icing. First, a mathematical model of the pressure relief valve is built, and then curves of the throttle area ratio of the pilot valve vs the pressure of the pilot valve cavity as well as its temperature are obtained by simulation, and the critical area ratio of the 2nd and 3rd grade air source is found to be 1.70 and 1.22 respectively. Simulation results show that the probability of icing can be reduced by decreasing the throttle area ratio of the pilot valve. A grid model of the pilot valve is built, and then the flow field distribution inside the pilot valve is calculated with Fluent, and the pressure distribution corresponds well with the result of theoretical calculation. Velocity contour and streamline indicate that whether icing will occur is concerned with the structure of the valve. Icing can be avoided by designing the flow passage properly.