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用一种粒子浓度、速度和角度可调的高过载模拟烧蚀发动机,开展过载条件下粒子冲刷对EPDM绝热层烧蚀特性影响的实验研究。实验结果表明:(1)存在一个临界速度,当冲刷速度低于临界速度时,粒子浓度,速度和角度对炭化烧蚀率影响较小,而当冲刷速度高于临界速度时,炭化烧蚀率随速度的增加而急剧增加,角度影响也较大。(2)弱冲刷条件下的炭化层表面平整,而粒子沉积条件下的炭化层表面附着有很多大粒径的粒子,炭化层结构也更加疏松,而强冲刷条件下,粒子由于速度较高而不易在炭化层表面沉积。(3)当低于临界速度冲刷时,炭化层的孔隙结构分布不均匀,存在致密/疏松分层结构,而高于临界速度冲刷时,炭化层结构则更为致密。(4)通过多元回归得到了炭化烧蚀率与粒子冲刷速度,浓度和角度的经验关系式。
An experimental study of the effect of particle scouring on the ablation characteristics of an EPDM insulation under overload was carried out with a highly overburden simulated ablation engine with adjustable particle concentration, velocity and angle. The experimental results show that: (1) there is a critical velocity. When the velocity of scouring is lower than the critical velocity, the influence of particle concentration, velocity and angle on the ablation rate of carbonization is small. When the scour velocity is higher than the critical velocity, the ablation rate With the rapid increase in the speed of increase, the impact of the larger. (2) The surface of the carbonized layer under the condition of weak scouring is smooth, while the surface of the carbonized layer under the condition of particle deposition has a lot of particles of large size and the charring layer structure is also more loose. Under the conditions of strong scouring, Not easy to deposit in the carbonized layer surface. (3) When below the critical speed of erosion, the carbonized layer pore structure distribution is uneven, there is dense / loose layered structure, while higher than the critical speed of erosion, the carbonized layer structure is more dense. (4) The empirical relationship between carbon ablation rate and particle erosion velocity, concentration and angle was obtained by multiple regression.