Evaluation of thermal effects on temperature-sensitive operating force of flow servo valve for fuel metering unit  

作　　者：Yang ZHANG Shaoping WANG Jian SHI Xi WANG 

机构地区：[1]School of Energy and Power Engineering,Beihang University,Beijing 100083,China [2]School of Automation Science and Electrical Engineering,Beihang University,Beijing 100083,China

出　　处：《Chinese Journal of Aeronautics》2020年第6期1812-1823,共12页中国航空学报（英文版）

基　　金：co-supported by the National Science and Technology Major Project of China (Nos. 2017-V-0011-0062,2017-V-0010-0060);National Natural Science Foundation of China (Nos. 51620105010,51875014 and 51575019);Natural Science Foundation of Beijing Municipality of China (No.L171003);Program 111 of China。

摘　　要：The temperature-induced variation in operating force of flow control valves may result in performance degradation or even jam faults of fuel metering unit(FMU), which significantly affects the safety of aircrafts. In this work, an analytical modeling approach of temperature-sensitive operating-force of servo valve is proposed to investigate the temperature characteristics in varying temperature conditions. Considering the temperature effects, a new extended model of flow force is built and an analytical model of valve friction is also derived theoretically based on the dynamic clearance induced by thermal effects. The extremum condition of friction is obtained to analyze the characteristic-temperature points where jam faults occur easily. The numerical results show that flow force increases firstly and then decreases as temperature increases under a constant valve opening. The maximum friction of flow servo valve can be uniquely determined when the structural parameters and ambient temperature are given. The worst situation just happens at the characteristic-temperature points, which are linearly related to the axial temperature gradients of valve spool. Such evaluations may give an explanation for the temperature-induced jam faults of vulnerable valves and provide a reference for designers to determine a suitable workingtemperature range of valves in practice.

关 键 词：Jam fault Servovalve Spool deformation Spool friction Temperature effect 

分 类 号：V228[航空宇航科学与技术—飞行器设计]