Study On Temperature Measurement Of Rocket Motor Gas Based On Multi-wavelength Spectrum Radiation

The combustion temperature of solid propellant is an important reference index for the study of combustion mechanism,structure design and thermal protection design of rocket motor.There are no stable and reliable methods to measure the temperature of rocket motor gas in the high temperature environment now.In this paper,the temperature measurement system of the rocket motor gas was designed and built based on multi-wavelength spectral radiation thermometry,the unsteady numerical simulation of the internal flow field in rocket motor was carried out,the temperature measurements of combustion chamber gas about three different formulations propellants were completed.The main work and conclusions are as follows:(1)The thermometry of rocket motor gas based on multi-wavelength spectral radiation was established.The thermometry is based on the Planck black body radiation law,the gas of rocket motor combustion chamber is regarded as the research object,by analyzing the wavelength and the radiation force of the gas radiation spectrum,the mathematical correspondence between spectral wavelength,radiation force and temperature is established,and the gas temperature is obtained.(2)The temperature measurement system of the rocket motor gas was designed and built.The system consists of the rocket motor for temperature measurement,the temperature measurement system based on multi-wavelength spectrum radiation,the thermocouple temperature measurement system,the charging system and the pressure data acquisition system.The performance of the temperature measurement system based on multi-wavelength spectrum radiation is as follows: effective measurement range of temperature is 1000-4000℃;Spectral wavelength measurement range is 200-1100nm;Integration time range is 8-1000 ms.(3)A unsteady numerical simulation model of the internal flow field in rocket motor was built.The unsteady numerical simulation of the internal flow field in rocket motor under different conditions was carried out.Simulation results show that the condensed phase particles are prevented from covering the surface of the transparent window glass,to ensure the transparent window glass clean.(4)The temperature measurements of combustion chamber gas about three different formulations propellants were carried out.And the average maximum temperature of the gas about three propellants collected by the spectrometer were 1239.5℃,1459.5℃,2627.5℃.The experimental results show that the charging system can ensure the transparent window glass clean;Charging does not affect the actual temperature collected by the spectrometer and the thermocouple;The higher the temperature is,the better the stability of the spectrometer.