畸变气流影响下C-SiC复合材料隔离段稳态特性试验研究

Experimental Study on Steady-State Characteristics of C-SiC Composite Isolator Considering Effects of Distorted Flow

关键词:  隔离段  激波串  畸变  粗糙度

Key words:  Isolator  Shock train  Distortion  Roughness

摘要:

为了研究畸变气流影响下烧蚀后的C-SiC复合材料隔离段性能，开展了马赫数2.5来流下模拟进气道喉道流场畸变的隔离段直连试验，同时对比研究了光滑不锈钢材质和不同目数砂纸隔离段性能，获得了C-SiC复合材料、不锈钢材质和砂纸隔离段的性能数据。结果表明:(1)烧蚀后的C-SiC隔离段的耐反压能力与光滑不锈钢材质隔离段相比下降了11.7%，总压恢复系数下降了6.96%，与40目砂纸隔离段相比，烧蚀后的C-SiC材料隔离段的耐反压能力和总压恢复系数更低；(2)烧蚀后的C-SiC隔离段性能大幅下降的实质在于表面不平度过大导致激波串前参数的改变，不平度越大，激波串前马赫数就越低，动量损失厚度也就越大，隔离段性能也相应下降更多。

Abstract:

In order to investigate the steady-state characteristics of the isolator with surfaces coated with a thermal ablation barrier C-SiC， the direct connect experiments considering the effect of distorted flow were conducted at various back pressures in Mach 2.5 flows. Meanwhile， the other two isolators， one with those surfaces covered with different mesh sandpapers， and one with smooth stainless steel materials， were studied comparatively to obtain the performance of three isolators. It was found that the thermal ablation C-SiC isolator can sustain a lower back pressure before unstarting the flow than the smooth stainless steel isolator about 11.7%， and the total pressure recovery coefficient decreased by 6.96%.Compared to the 40 mesh sandpaper isolator， the isolator equipped with rough thermal ablation C-SiC material exhibits even worse shock holding capability and total pressure recovery. The essence of thermal ablation C-SiC composite impacting the isolator’s performance is the change of flow parameters before shock train because of the high surface roughness. The surface roughness is higher， Mach number before the shock train is lower， and momentum loss thickness is bigger， so the isolator’s performances fell sharply.