电推进系统工质气体微流量校准装置的设计

Design on Working Gas Micro-flow Calibration Apparatus for Electric Propulsion System

通过实验和理论分析,结合电推进系统工质气体微流量的实际使用情况,提出了绝压定容升压法及差压定容升压法两种电推进系统工质气体微流量的校准方法,设计了电推进系统工质气体微流量校准装置,装置采用双通道对称结构,包括抽气系统、校准系统、容积测量系统、稳压系统、多工质气路转换系统、恒温及烘烤系统、数据采集系统等,校准范围为5×10^(-5)～5×10^(-1)Pa·m^3/s,入口压力为0.2～0.5 MPa,出口压力为100 Pa～0.2 MPa,扩展不确定度小于2.0%(k=2),校准气体为Xe、Kr、Ar、He和N_2,可以满足电推进系统的计量需求。

In this paper, two calibration methods are introduced for working gas micro-flow calibration for space electric propulsion system. One is absolute pressure constant volume rise pressure method and the other is differential pressure constant volume rise pressure method. Based on two calibration methods, a new calibration apparatus for working gas micro-flow to space electric propulsion system is designed, and the apparatus can be roughly divided into seven parts, pumping sys-tem, calibration system, volume measuring system, stabilizing pressure system, multiple working gas path switching system, constant temperature and baking system, data acquisition system. Its calibration range is from 5×10^-5 to 5×10^-1 Pa· m^3/s, inlet pressure is from 0.2 to 0.5 MPa, expansion uncertainly is less than 2.0%(k=2), calibration gases are Xe, Kr, Ar, He and N2. The performances of present calibration apparatus meet the demand for practical requirement for space electric propulsion system.