基于微波CT的固体火箭发动机燃面退移动态测试方法研究

Research on Test Method of Burning Surface Retreat State of Solid Rocket Motor Based on Microwave CT

现有的X射线、超声等无损检测技术受检测工艺、设备安装、检测效率等限制,无法实现固体火箭发动机燃面退移过程的动态测试需求.本文研究了一种微波CT检测燃面退移的方法.根据微波CT成像原理,将天线等角度间隔分布于固体火箭外壳表面,建立燃面退移变化的数学模型.考虑到微波是以曲线形式传播的,不能使用传统的射线CT重建的直线投影矩阵刻画方法.因此根据微波传播路径,完成微波CT重建的投影矩阵刻画,并根据各个微波天线测量值,利用改进的ART-TV算法重建燃面退移变化的动态图像.仿真结果表明,本文研究的微波CT成像方法可以有效表征固体火箭发动机燃面退移变化,并且利用改进的ART-TV算法重建得到的直径为39~159 mm的燃面重建误差小于1 mm,可为后续实验测试系统的设计及验证提供理论支撑.

Existing non-destructive testing technologies such as X-ray and ultrasound are limited by the testing process,equipment installation,and testing efficiency,and cannot meet the dynamic test requirements of the burning surface retreat process of solid rocket motor.This paper proposes a method of detecting the burning surface retreat through microwave CT.According to the microwave CT imaging principle,the antennas are distributed at equal angular intervals on the surface of the solid rocket shell,and a mathematical model of the burning surface retreat is established.Considering that the microwave propagates in a curved form,traditional linear projection matrix characterization methods cannot be used for ray CT reconstruction.Therefore,the projection matrix characterization of the microwave CT reconstruction is completed according to the microwave propagation.And an improved ART-TV algorithm is used to reconstruct the dynamic image of the burning surface degeneration according to the measured values of each microwave antenna.The simulation results show that the microwave CT imaging method studied in this work can effectively characterize the change of the burning surface retreat of solid rocket motors.The reconstruction error is less than 1 mm of the burning surface with a diameter of 39~159 mm reconstructed by the improved ART-TV algorithm,which can provide theoretical support for the design and verification of subsequent experimental test systems.