基于多尺度耦合分析的高超声速引射气体边界层降热减阻机理研究

The heat blockage effect caused by pyrolysis gas injection is a complicated multi-field coupled process, which would have remarkable effects on the ablative performance of resin-based material and the aerodynamic/aerothermal characteristic of hypersonic vehicles. The study on the heat/drag reduction mechanism of pyrolysis gas injection has both important academic significance and engineering application value. In this work, the multi-field coupling mechanism of pyrolysis gas injection is numerically investigated by the micro pore-scale and macro REV(Representative Elementary Volume) scale analysis methods. The multi-scale flow and heat transfer mechanism in the porous carbonized layer, evolution of boundary layer with gas injection, the high temperature flow characteristic with pyrolysis gas combustion would be explored. The mechanism of the heat/drag reduction of hypersonic boundary layer with pyrolysis gas injection would be revealed. The research results of this project will help to improve the understanding of the oxidation and ablation mechanism of resin matrix composites in service environment, and provide support for the accurate evaluation of aerodynamic/aerothermal characteristics of near space hypersonic vehicle and the design of thermal protection system.

热解气体引射带来的热阻塞效应是流动/传热/传质/化学反应等多场耦合的复杂物理化学过程，对树脂基烧蚀材料的抗氧化烧蚀性能及高超声速飞行器的气动力/热特性均有显著影响，开展高温烧蚀条件下热解气体引射作用的降热减阻机理研究兼具重要的学术意义和工程应用价值。本项目分别基于微观孔隙尺度和宏观REV尺度（Representative Elementary Volume）的耦合分析方法对树脂基复合材料烧蚀过程中热解气体引射效应的多物理场耦合机制开展数值模拟研究，探讨多孔碳化层内的多尺度流动与换热机制、引射气体边界层的演化发展规律、热解气体燃烧的高温流场特性及三者的耦合作用机理，揭示高超声速引射气体边界层的降热减阻机制，提高树脂基复合材料的氧化烧蚀预测精度。本项目研究成果将有助于提高对真实服役环境下树脂基复合材料的氧化烧蚀机理的认识，为临近空间高超声速飞行器气动力/热特性精确评估及热防护系统设计提供支撑。

本项目围绕树脂基复合材料烧蚀过程中热解气体引射效应的流动/传热/化学反应/烧蚀等多物理场耦合问题，完善了所发展的多孔介质/流体/固体多区域流热耦合数值模拟程序以及能够考虑热化学非平衡效应的气动热分析软件，并以此工具对树脂基复合材料烧蚀过程中热解气体引射效应的多物理场耦合机制开展深入研究，探讨了复杂高温主流与多孔碳化层内部流动的相互耦合作用机理，总结了不同热解气体类型、注入率、主流区激波干扰、表面压力梯度、热解气体燃烧等对热阻塞效应的影响规律，揭示了复杂来流条件下高超声速引射气体边界层的降热减阻机制；以此为基础建立了烧蚀热防护系统热响应计算模型，发展了高超声速气动热环境下的烧蚀热防护系统热响应及高温热物性参数辨识程序，并经过典型算例及地面风洞试验数据验证，显著提高树脂基复合材料的氧化烧蚀预测精度，为临近空间高超声速飞行器烧蚀热防护系统的精细化设计提供了重要的技术支撑。