Research On Measurement Method Of Two-Dimensional Temperature Field Of Mg/CO₂ Combustion Flame Based On Color CCD

Mg/CO₂ powder rocket engine is a new type of rocket engine based on Mars exploration background.The temperature field of combustion flame of Mg/CO₂ powder rocket engine is one of the important parameters that reflects the flame radiation characteristics,the performance of powder fuel and the working condition of the engine.Accurate measurement of Mg/CO₂combustion flame temperature field has important reference value for understanding the working condition of powder engine combustion chamber and evaluating the comprehensive performance of powder engine.Radiation image temperature measurement is a new type of temperature measurement technology developed in recent years.This temperature measurement technology is based on a color CCD image sensor,combined with photoelectric conversion technology and digital image processing technology,and uses the principle of radiation temperature measurement to obtain temperature results.The radiation image temperature measurement method has many advantages,such as simple structure,high temperature measurement accuracy,and fast temperature response.It is suitable for non-contact measurement of Mg/CO₂ combustion flame temperature field.Based on Planck’s radiation law and colorimetric thermometry principle,this paper uses a color CCD camera as the main body to build an experimental system capable of measuring the temperature of high-temperature objects,and applies this experimental system to the Mg/CO₂combustion flame temperature field.Measurement.Before measuring the temperature field of Mg/CO₂ combustion flame,the experimental system was calibrated through a high-temperature standard radiant blackbody furnace,and the relationship curves between the response coefficient Cg and the correction coefficient k and the temperature were obtained.The temperature method is used for verification.The values of the corresponding response coefficient Cg and correction coefficient k at the set temperature are substituted into the colorimetric temperature measurement formula to obtain the measured temperature value.The error between the set temperature and the set temperature is less than 1.2%.Reliability of temperature method in the measurement of high temperature objects.On this basis,the color CCD radiation image temperature measurement method was used to measure the temperature field of Mg/CO₂ combustion flame,and a two-dimensional temperature field distribution image of Mg/CO₂ combustion flame was obtained.The experimental conditions were designed,and the effects of Mg powder particle size,Reynolds number of premixed gas flow,and Mg/CO₂ oxygen-fuel ratio on the temperature field of Mg/CO₂ combustion flame were studied.The conclusions are as follows:（1）The CO₂/Mg stable combustion flame temperature is between 2500K-2900K under all conditions.（2）When the Reynolds number and the oxygen-fuel ratio are the same,the outlet temperature value decreases as the particle diameter increases.（3）When the Mg particle size and oxygen-fuel ratio are the same,the outlet temperature value decreases as the Reynolds number Re increases.（4）When the Mg particle size is the same as the Reynolds number,as the oxygen-fuel ratio increases,the outlet temperature value decreases.