陶瓷基点阵夹芯结构等效传热系数的数值模拟分析

Numerical analysis of the effective coefficient of heat transfer of ceramic composite sandwich structure with lattice core

为了评价陶瓷基点阵夹芯结构的热防护效能,选取陶瓷点阵夹芯结构的胞元作为研究对象,给出了表征其传热效能的等效传热系数计算方法。建立了点阵夹芯结构胞元的导热-辐射稳态耦合传热的有限元模型,通过对模型施加不同的边界条件,利用数值模拟的方法求出了点阵夹芯结构稳态温度场分布和等效传热系数,并对其换热机理和影响因素进行了分析。研究表明:点阵夹芯结构的辐射换热是结构热传导的主要方式,且随温度的升高其辐射传热效应就越强;较大的芯杆高度能够降低结构的传热效能;增加芯杆直径会提升结构的热防护能力;芯杆倾角对结构的热防护性能影响较小。

In order to evaluate the thermal protection ability of ceramic lattice sandwich structure,the cell of ceramic lattice sandwich structure is selected as the research object,and the calculation method of equivalent thermal conductivity to characterize its heat transfer efficiency is given.By establishing the Finite Element model of heat conduction radiation steady-state coupled heat transfer of Lattice Sandwich Structure cells,applying different boundary conditions to the model,the steady-state temperature field distribution and equivalent thermal conductivity of lattice sandwich structure are obtained by numerical simulation,and its heat exchange mechanism and influencing factors are analyzed.The results show that the radiation of lattice sandwich structure is the main mode of structural heat conduction,and the radiation plays a stronger role with the increase of temperature;Relatively small material emissivity and large core height can reduce the heat transfer efficiency of the structure;Reducing the diameter of the core rod will reduce the thermal protection ability of the structure;The inclination angle of the core rod has little effect on the thermal protection performance of the structure.