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热防护技术是高超声速飞行器再入的重要技术,而轻质蜂窝材料是热防护技术中大量采用的防热材料,在地面试验中超声速自由射流驻点烧蚀是考核防热材料烧蚀性能的有效手段。大尺寸平面驻点烧蚀试验中,烧蚀表面热流分布不均匀,使得试验过程中烧蚀表面的形状发生改变,从而造成试验状态的偏离,最终导致烧蚀结果的误差,采用球面等热流外形设计可以有效解决该问题。详细介绍了驻点烧蚀的试验方法和试验设备,简要说明了热流测量的工程算法和理论原理,进而着重阐述了平面驻点模型对烧蚀结果的影响,并根据试验和计算结果给出了改进烧蚀表面热流均匀性分布的等热流球面方法,最后结合试验对球面模型和平面模型的热流测量及烧蚀结果做了详细的对比分析,解释了平面模型产生较大烧蚀量误差的原因。
Thermal protection technology is an important technology for hypersonic aircraft reentry. Light honeycomb materials are widely used in thermal protection technology. In ground tests, ablation of supersonic free jet is to evaluate the ablation performance of heat-resistant materials Effective means. In the large-size plane stagnation ablation test, the uneven distribution of ablation surface heat flow makes the shape of the ablated surface change during the test, which leads to the deviation of the test state, which eventually leads to the ablation result error. Design can effectively solve the problem. The experimental and experimental equipment for stagnation point ablation are introduced in detail. The engineering algorithm and theoretical principle of heat flow measurement are briefly described. Then the impact of planar stagnation model on the ablation result is emphatically explained. Based on the experiment and calculation results, The heat flux and the ablation results of the spherical model and the planar model are compared and analyzed in detail, and the reasons for the large ablation error caused by the planar model are explained .