结构瞬态热流及喷射热流热辐射仿真技术研究

Research on Transient Heat Transfer Simulation of Structural under Transient Heat Flux and Jet Flow Radiation Boundary Condition

作动器是航天发动机用于推力向量控制的一种重要伺服机构,用来调整发动机喷管的姿态,本文以作动器为研究对象,针对对流和辐射两种典型边界,分别研究两种典型边界下结构传热过程。通过研究热壁热流与冷壁热流关系,进而对冷壁热流进行修正得到热壁热流,解决了热流边界模拟中环境热与净吸收热不匹配问题。针对热辐射边界,本文基于辐射热流分布半经验公式,根据局部辐射热流值对公式进行最小二乘拟合,得到辐射热流分布,将拟合后辐射热流分布函数作为热辐射边界条件,进而进行传热分析,解决了由于有限元软件对非测点位置节点进行外推插值而导致局部辐射热不准确的问题。

The actuator, which is used to adjust the posture of the engine nozzle, is a crucial part of spacecraft flight control. The heat transfer process under transient heat flux and jet flow radiation is studied in this paper. The problem of mismatch between the environmental heat and the net absorption heat in heat flux boundary simulation can be solved by getting the hot wall heat flux, which is fixed by the cold wall heat flux. For the jet flow radiation boundary, according to the local radiant heat flux, the radiant heat flux distribution is fixed based on the semi-empirical formula in this paper by least square method. Then the heat transfer is carried out by using the formula,which can be fitted as boundary condition. The problem of radiant heat flux inaccuracy caused by extrapolation on non-measurement position nodes calculating is solved in this paper.