固体火箭发动机真实热环境下EPDM绝热层烧蚀计算与试验研究

Calculation and experimental study of EPDM insulation ablationof solid rocket motor under realistic operation conditions

基于Hertz弹性碰撞理论和Thornton弹塑性假设,导出了粒子碰撞炭层过程中的压痕硬度理论表达式,根据弯管试验数据和试件扫描电镜分析提出了临界速度模型,对于三元乙丙橡胶(EPDM)炭化后形成的多孔炭化结构,结合裂纹侵蚀理论提出了两相流非完全弹性碰撞多孔炭化层体烧蚀计算模型。设计了用于验证烧蚀计算模型的模拟发动机旋转过载试验,保证了模拟发动机和真实发动机的天地一致性。结果表明:在模拟发动机真实飞行过程的热环境下,计算结果与实测结果能够基本吻合。研究结果对固体火箭发动机绝热结构的设计具有工程指导意义。

Based on the Hertz elastic impact theory and Thornton elastoplastic hypothesis,the theoretical expression of indentation hardness during particle impact on carbon layer was derived.A critical velocity model was proposed based on convergent tube experiment data and scanning electron microscopy analysis of specimens.Combined with the crack erosion theory,a porous carbonized layer body ablation calculation model under two phase fluid incompletely elastic collision is proposed for the porous carbonized structure formed by the ablation of EPDM rubber.A simulated solid rocket motor rotation test was designed to verify the calculation model above,which could eliminate the discrepancy between the ground simulated motor and the real motor working in air.The test results show that the calculated results are in good agreement with the measured results under the thermal environment which simulating the real flight process.The research results of this paper have engineering guidance significance for the design of insulation structure of solid rocket motor.