针对大直径固体火箭发动机复合喷管的热结构耦合问题,编写了非均布载荷与非均布对流换热系数子程序,采用三维有限元方法,获取了在热载荷与内压联合作用下热防护材料内部温度场与应力场分布。研究表明,热载荷是引起喉衬应力与壳体应力的主要原因。其次,小界面间隙对热防护材料内部应力强度影响不明显。最后,采用文中数值方法,为喷管界面搭接与缝隙设计提供指导,也可应用于评估喷管热防护与结构强度安全余量。

According to the thermal structure coupling problem of composite nozzle of large diameter solid rocket motor, the subroutine of non-uniform load and non-uniform heat convection coefficient was written, and the 3D finite element method was used to obtain the distribution of temperature field and stress field in thermal protection material under the combined action of thermal load and internal pressure. The results showed that thermal load was the main cause of throat lining stress and shell stress. Secondly, small interfacial gap had no obvious impact on the internal stress intensity of thermal protective materials. Finally, the numerical method presented in this paper could provide guidance for the design of nozzle interface overlap and gap, and could also be applied to evaluate the thermal protection and structural strength safety margin of nozzle.