Uncertainty evaluation of thrust measurement system for small space combined nozzle

WEI Wenquan, LU Yonghua

（College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and
Astronautics, Nanjing 210016, China）

Abstract: Aiming at measurement uncertainty evaluation problem of combined nozzle thrust measurement system, the measurement principle of combined nozzle thrust was introduced, and the location of the sensors load surface and the correction coefficient of thrust were determined by the calibration experiment, and the uncertainty sources of thrust measurement system were analyzed. Its measurement uncertainty was evaluated by using type A uncertainty component and type B uncertainty component, and the type A uncertainty component of each channel was calculated by using the Bessel method, and the type B uncertainty component of each segment of thrust measurement system was calculated. The results indicate that the type B uncertainty component of each channel is close to each other, and the size of synthetic standard uncertainty and expanded uncertainty of each channel is largely determined by type A uncertainty component, which is related to the size and the internal structure of nozzle.

Key words: measurement uncertainty; combined nozzle; thrust measurement; thrust calibration; error sources