An Inventigation On Dynamic Thrust Measuring Technolgy For An Atittitude Control Liquid Propellant Rocket Engine In The Ground Firing Test

The dynamic thrust measure technology for high-altitude simulation test of the attitude control Liquid Rocket Engine was studied in the thesis. There are increasing demands from the advanced space propulsion systems. In terms of these requirements, the test system is capable of measuring the states exactly and validly. When an engine works under the vacuum condition. So existing experimental products can be proof-tested by it and all test results obtained will be used for reference for the aero craft. Accordingly, the technology studied in the thesis is quite significative to improve the efficiency of the engines of space propulsion system, economize limited resources on the spacecrafts, and prolong their lives.In this thesis, many state-of-the-art schemes of force measure system are introduced, analyzed and compared at first. Then the universal model used is summarized, which shows that the dynamic thrust measuring technology is feasible. Based on a view to the practical purposes and the known project experiences, some main problems, such as a large-scale system vibration, thrust-frame response, signal transmission, pipeline stress of propellant and thrust calibration, are considered. In order to solve these problems, firstly, the mathematical model of the system is simplified based on dynamic measuring theory and practical expense. A data processing compensation program, which is capable of computing compensation and can be utilized under practical conditions, is designed by using the simplified model. Then, based on vibration theory, a vibration isolation device between the test platform and the thrust measuring system is deployed. So the effect of vibration can be decreased. Considering the characters of the engine, materials selecting and structure designing of the thrust-frame are optimized under the preconditions of maintaining intensity and safety. What's more, since the dynamic thrust measuring system has some special requirements to sensors, in order to avoid additional error from sensors, it is technically designed on selecting for charge transmission and second-instruments. At the same time, the stress influence between the propellant pipeline and engine is an unavoidable restriction, which is also considered in the thesis.Finally, by practical test, experimental data obtained show that the dynamic thrust measuring system is dramatically available and successful. Especially, it shows that when the impulse width is 20ms and the duty ratio is 1:3, the measured results are stable and reliable. Hence, the system designed here can meat the test requirements of the actual applications, and the technology studied in the thesis also give a good foundation to future research work.