Study On Thrust Vector Test System For The Engine

With the continuous development of space expolration and aerospace technologies in recent decades, rocket engine as an engine of the spacecraft core plays a crucial important role. Because the engine works at the harsh environment which is high temperature, high pressure and parameters ever-changing, large number of tests need to be performed for precise controlling operation posture, orbit transfers and thrust characteristics of the engine. As an important indicator to access engine performance, accurate measurement of engine thrust vector is one of the major problems to be solved.In this paper, the engine thrust vector measurements are the object of study. Reviewed the status of development, testing principle of thrust measurements and compare the pros and cons associated test methods. A thrust vector test system based on the piezoelectric effect is developed from deep analysis of the theory, practice and other aspects, and through calculation, simulation verification, combined with research achievement piezoelectric testing.According to thrust vector test requirements, the paper designs a four-sensor type structure, and each sensor can achieve three orthogonal force measuring. Through theoretical calculations to determine the optimal sensor placement methods of the four sensors in the dynamometer, this piezoelectric dynamometer is the core component in test system, to ensure that the natural frequency of the dynamometer to meet the design requirements, using the finite element method to carried out modal analysis to verify its natural frequency from theory. The structural design and mechanical properties is performed to the main supporting components of the system to determine the feasibility of structure design. Static calibration system is established to carry out dynamometer static calibration, in order to ensure its static performance indicators reaching the test requirements of system. The paper select the hydraulic loading device as the loading device of test systems, in order to ensure the dynamometer accurately calibrated and tested in test system, and the back-end straight pull and inclined pull device is designed, and drag link mechanism was checked calculation to verify whether it satisfies the mechanical requirements. On this basis a static calibration for normal force and skew force is performed, in order to accurately measure the output characteristics of test system in different conditions, conducted a lot of comparative test, and get a lot of experimental data. Using MATLAB to design procedures for rapid calculation, and the paper obtained the calculation results for the static calibration of test system, combined with the characteristics of big weight ratio loading to carry out compensation deals for the test system data, and get optimal compensation results.After the relevant test data processing, the paper carried on uncertainty analysis for assessing the good or bad of the thrust vector parameter, and gets the relevant performance indicators. Experimental results show that static properties of thrust vector test system is good, linearity, repeatability error is less than1%, and interference among different phases are within2%, uncertainty indicators were within3%, all meet the technical requirements.