极端环境下接触缝隙的热-流-固耦合关系及性能表征研究

In the extreme environment of high temperature and high pressure gas flow, the ablation is inevitable and remarkable on the thermal protection layer of spacecraft. To meet the needs of structures and applications, several kinds of gaps should be designed in the thermal protection structure. Non-uniform distribution of heat flux and pressure result in the geometrical deformation of the gaps, or even the contact in some areas of gaps (namely contact-gaps), and contact-gaps will bring about a more complex thermal-fluid- solid coupling problem. Under the background of great demands for thermal protection of the spacecraft, gaps in the nozzle of solid rocket motor are regarded as the main object of study. Firstly, this project designs a set of test system and test methods to obtain the heat-flux distribution in gaps, specially does the experiment of the local thermal effect in typical gaps. Secondly, based on the technology of cloud computation, a Lagrange vortex method will be developed to simulate the gas flow in gaps under the complex boundary conditions. Thirdly, in order to analyze the thermal-fluid-solid coupling relationships in contact-gaps, this project combines with the finite element method, finite difference method and dilating vortex particle method on the basis of the experimental data and multidisciplinary theory such as heat transfer, ablation science, computational fluid dynamics and so on. Then, this project will be able to reveal the mechanism of local thermal effect in gaps in the extreme environment and explore an evaluation method about the local thermal effect in gaps. Finally, based on the above findings, we will bring to light a new characteristic parameter defining the gap the local thermal effect by using the random mathematical methods and statistical theory. This study will promote the development of interdisciplinary, which has both the important theoretical significance and the important defense application value.

航天飞行器在高温、高压气流的极端环境中服役，热防护层常出现烧蚀现象；由于结构和应用的需要，热防护结构必须设计各种缝隙；热流和压力的不均匀性将导致缝隙的形状变化，甚至部分接触；接触缝隙将引起更复杂的热-流-固耦合问题。本项目将以固体火箭发动机喷管喉衬上缝隙为主要研究对象，设计一套缝隙热流的测试系统与方法，对典型缝隙的局部热效应进行测试，建立相关缝隙热流的动力学模型；基于云计算平台技术，改进拉格朗日涡方法，研制专用软件来模拟复杂边界条件下的缝隙气流；基于试验数据，利用传热学、烧蚀学、计算流体动力学等多学科的交叉与渗透，结合有限元法、差分法与胀量涡方法，分析接触缝隙的热-流-固耦合关系，揭示极端环境下接触缝隙局部热效应的机理；基于以上研究，应用随机数学和统计学理论提炼出缝隙局部热效应的表征参量，有利于缝隙局部失效的评价。本研究将推进交叉学科的发展，具有重要的理论意义，又具有重要的国防应用价值。

航天飞行器由于结构和应用的需要，热防护结构必须设计各种缝隙；热流和压力的不均匀性将导致缝隙的形状变化，甚至部分接触；接触缝隙将引起更复杂的热-流-固耦合问题，对飞行器热防护科学和技术提出了严峻的挑战。. 本项目实施以来，紧紧围绕“极端环境下缝隙的热-流-固耦合关系”的关键科学问题，开展了系统性基础研究，取得了如下重要创新成果：.一、.采用理论分析、模型实验与数值模拟相结合研究手段，发挥多学科的交叉创新的优势，用“复合材料、结构、流场、热、烧蚀”一体化的思想研究了接触缝隙的热-流-固耦合问题，探索了极端环境下缝隙热流变化的规律，揭示了接触缝隙局部热效应的机理，提炼出接触缝隙局部热效应的性能表征参数。.二、.提出了超高音速飞行模拟的新策略与新技术，开发了超高音速飞行计算流体动力学精细化数值模拟平台，建立了超音速飞行器上接触缝隙的热-流-固耦合模拟系统，实现了对接触缝隙局部热效应从简单效应分析到多效应耦合的全过程分析的跨越。. 在本项目资助下，研究组成员发表论文33篇，其中22篇SCI收录、2篇EI收录；出版中文专著1部；已授权发明专利2项，软件著作权1项；国际学术会议报告3次，国内学术会议报告7次。培养博士研究生6名，硕士研究生8名，为我国航天工程培养了一支多学科交叉合作、年富力强的高水平研究队伍。本项目研究将推进交叉学科的发展，具有重要的理论意义，又具有重要的航天工程应用价值。