Development On Six-component Balance System For Measuring Plane Engine Vector Nozzle

With the development of the modern aviation industry, the vector thrust technology was regarded more and more important as the essential technology of modern fighter plane . Developing vector nozzle technology, researching on vector nozzle and taking it experimentation have all been the common viewpoint and the research hotspot in the international aviation field . So, the routine single DOF(Degree of Freedom) measuring platform was not satisfied the practicality need anymore. Thus , we start developing on six-component balance system for measuring plane engine vector nozzle .This research work apply strain balance to measuring the vector thrust of plane engine for the first time at home. And it also solved the connect problem between the fixed gas pipeline and measuring platform . The system has great load, higt precision and good stability .In this paper, the technology target of the system and the course from design , machining , assembly to calibration were all introduced . The author researched on the structure form of the system, the design and calculation of the six DOF balance, elimination measure of hot stress and the fixing method . In the research of unitary calibration technology , the author creationary solved the calibration problem of the unitary measuring system by analyzing the the theory cause of infection factor acting principium and the experimentation data . The system has completely achieved the design technology target, and could satisfy the need of vector nozzle for performance experiment .The system consist of five parts. They are balance fixed base, six-component balance, nozzle experiment device, fixed air intake pipeline and scene static calibration device. Six-component balance is the kernel of the system, and it is designed to be constructional cassette balance. The balance is composed of fixed frame, floating frame and four high precision three-dimension force sensors. Nozzle model experiment device is mounted on the balance.Considering that the temperature in pipeline of the nozzle model experiment device is high up to 2000 K , the author took measures to defend hot scathe. The measures included water cooling, thermal expansion cell, expanding radiating area, extending radiating distance and taking temperature compensating measures to the balance. Thus , when the system takes high temperature experiment, it's safety and precision could be ensured.The system adopt two symmetrical stretch ripple tube as gas homing pipeline to connect the measuring platform and the air intake pipeline. This measure settled the problem that air source supply effects the system measurement. At the same time , it also settled air leak and harsh noises. The infection by ripple tube to the system could be amended by assembly and calibration.Combining single-component load method and integration load method , scene static calibration obtained good result. At first, the system took dynamic calibration with air no-flowing. Then , it took standard vector nozzle model experiment . By this way, we did dynamic calibration step by step. With the theory cause analysed, based on the balance calibration expressions, we amended the system's using expressions by taking temperature and pressure as independent variable. It indicates this system designed scientifically and reasonably that only one time dynamic calibration experiment with air no-flow could satisfy technology need of the system. The author also did contrast experiment to validate the calibration result by using an axi-symmetrical convergent-divergent vector nozzle which was used before.