放气活门用金属膜盒压力-位移特性

Pressure Displacement Characteristics of Metal Bellows for Air Bleed Valves

某型航空发动机采用放气活门放掉压气机出口部分空气以防止发动机喘振,放气活门配套的金属膜片膜盒组件作为压力敏感元件,膜盒的压力-位移特性直接影响放气活门的控制性能。基于金属膜盒的工作原理及使用环境,从膜盒结构出发得出膜盒的一般特性表达式。结合膜盒有效工作面积,使用有限元分析的方法得出膜盒组件的压比-位移方程。结果表明,膜盒的位移随压比呈线性关系,并且随着环境压力的降低,膜盒组件达到最大位移的压比升高,通过搭建膜盒组件试验台对仿真结果进行了对比与验证。为放气活门的系统建模分析与航空发动机控制性能的提升提供理论基础。

A certain aero-engine use air bleed valves to release part of air from compressor outlet to prevent engine surge.Metal diaphragm bellows of vent valves are pressure sensitive elements.Pressure displacement characteristics of diaphragm directly affect control performance of vent valves.Based on working principle and operating environment of diaphragm bellows,general characteristic expression of diaphragm bellows is obtained from the structure.Combined with effective working area of diaphragm bellows,pressure ratio-displacement equation assembly is obtained by using finite element method.Results show that displacement of diaphragm bellows is linear with pressure ratio,and pressure ratio of diaphragm bellows component to reach the maximum displacement increases with decrease of ambient pressure.Simulation results are compared and verified by building a test bed of diaphragm bellows component.It provides a theoretical basis for modeling and analysis of vent valve system and improvement of aero-engine control performance.