考虑流固耦合作用的一维供应管路喷嘴系统动力学特性

Dynamic Characteristics of One-Dimensional Feeding Pipe-Injector System Considering Fluid- Structure Interaction

关键词:  流固耦合  供应管路-喷嘴系统  传递矩阵法  动态特性

Key words:  Fluid-structure interaction  Feeding pipe-injector  Transfer matrix method  Dynamic characteristics

摘要:

为了更加深入地研究供应管路-喷嘴系统的动态特性，在喷嘴动力学理论的基础上，建立了考虑供应管路流固耦合作用的传递矩阵组合计算模型。针对三种典型液体火箭发动机喷嘴与一维供应管路组成的系统，开展了两端固定边界的系统动力学特性数值模拟。结果表明:管路结构谐振与管内流体谐振所导致的喷嘴出口位置流体速度振荡量级相当，管路流固耦合作用对系统动态特性的影响不能忽略；管路结构谐振是造成其固定位置应力的频率响应幅值较高的主要因素；当流体与结构的谐振频率接近时，会产生一个大带宽、高幅值的应力耦合振荡区间，随着管壁厚度的增大，耦合振荡的带宽也随之增大；对于文中算例，流固耦合作用对流体谐振造成的系统振荡具有约5%的降频作用。

Abstract:

To study the dynamic characteristics of feeding pipe-injector system，a combined transfer matrix model is set up considering fluid-structure interaction in feeding pipe based on dynamic theories of liquid injector. A numerical investigation concerning about the characteristic of systems consisting of one-dimensional feeding pipe and three kinds of conventional injectors in liquid rocket engines with fixed-fixed boundary condition is carried out. Results indicate that the flow velocity oscillation at injector exit caused by structure and fluid has a comparable scale，so the influence of fluid- structure interaction in pipe cannot be ignored. Structure resonance is the main factor which induced a higher stress response at fixed boundary of the pipe. There is a wide-band and high-amplitude frequency interval of coupled oscillation in stress，when the resonant frequencies of structure and fluid are close. As the thickness of pipe increases，the bandwidth of stress oscillation becomes wider. Numerical examples also show that，with fluid-structure interaction effect，oscillation frequencies of flow velocity and structure stress induced by fluid resonance decrease by about 5%.