氧化硅体系非牛顿流黏性烧蚀行为分析

An Analysis of Ablation Behavior for Nonnewtonian Fluids for Oxy-Silicon Composites

黏性系数对氧化硅体系材料的烧蚀速度有很大的影响,本文对非牛顿流黏性影响的范围及其量值作了数值模拟和分析。结果表明：（1）牛顿流黏度（s=1）处于烧蚀速度的低值区域,增加黏度对降低烧蚀速度的潜力不大;（2）非牛顿流黏度（s〉1）,可以增加阻力,但对降低烧蚀速度极为有限,在本文研究的热环境条件,其下降额度约为20%-30%,此时烧蚀速度接近全蒸发的烧蚀速度;（3）非牛顿流黏度（s〈1）,可以降低阻力,烧蚀速度明显增加。

There is a severe influence of the viscosity change upon ablation recession rate for oxy-silicon composites. The numerical simulation and analysis of ablation behavior for nonnewtonian fluids are presented. The analysis results show ： （ 1 ） The ablation recession rate of newtonian fluids is in lower region. （2） The resistance may be increased with viscosity augmentation（ s 〉 1 ） for nonnewtonian fluids, but the decreasing value of recession rate is very finite and the value limit is close to evaporation velocity. （3）The resistance may be decreased with viscosity abatement （ s 〈 1 ） for nonnewtonian fluids and the recession rate increases evidently.