气动热载荷作用下固体火箭发动机热流固耦合振动研究

【作者】 蒲炜强； 周博成； 杨海威； 苏成志； 王革；

【机构】 哈尔滨工程大学航天与建筑工程学院；

【摘要】 采用热流固耦合数值仿真方法对固体火箭发动机工作过程中出现的天地不一致性不稳定问题开展研究,重点关注飞行过程中发动机外部热载荷对发动机结构振动响应的影响。对不同壳体温度下的发动机结构振动模态进行分析,获得发动机结构固有振动频率随工作阶段变化的规律,并与内流场声腔模态进行对比。研究发现,气动热载荷作用会导致发动机结构的各阶振动频率下降,引发发动机结构的二阶弯曲频率与声腔的一阶振动频率相接近,从而增加了发动机结构与内流场在特定频率下耦合振动的可能性。通过对气动热载荷作用下发动机结构和流场脉冲激励双向流固耦合研究,获得了不同壳体温度下对发动机施加特定触发频率激励后内流场与结构的耦合振动规律,耦合振动将引发燃烧室平均压力不稳定上升,发动机壳体的振动幅值明显增加。论文工作可为自由飞行条件下固体发动机不稳定燃烧的研究提供参考。更多还原

【Abstract】 The thermal fluid-structure coupling numerical simulation method is used to study the inconsistency and instability of solid rocket engine during operation,focusing on the influence of external thermal load on the vibration response of engine structure during flight in this paper.The vibration modes of the engine structure at different shell temperatures were analyzed,and the variation of the natural vibration frequency of the engine structure with the working stage was obtained,which was compared with the acoustic cavity modes of the inner flow field.It is found that the aerodynamic thermal load will lead to the decrease of the vibration frequency of the engine structure,and the second-order bending frequency of the engine structure is close to the first-order vibration frequency of the acoustic cavity,which increases the possibility of the coupling vibration of the engine structure and the internal flow field at a specific frequency.Through the engine structure under the action of the pneumatic heat load and two-way flow field pulse fluid-structure interaction research,obtained under different shell temperature on engine within a particular trigger after excitation frequency coupling vibration law of flow field and structure,the coupling vibration will cause unstable combustion chamber average pressure rise,engine vibration amplitude increase significantly.The work in this paper can provide a reference for the study of unsteady combustion of solid engine under free flight condition.更多还原