航空发动机管路流固耦合振动的固有频率分析

为研究流体哥氏力和管路参数等因素对航空发动机管路固有振动频率的影响规律,采用Galerkin方法建立了管路流固耦合数学模型,并通过复特征值分析得到了系统的固有频率。通过将采用Galerkin方法的计算结果与试验测试数据进行比较,验证了Galerkin方法的正确性;给出了试验管路的临界流速,并研究了流体哥氏力和管路截面尺寸对系统固有频率的影响。结果表明:试验燃油管路实际流速远小于发生屈曲失稳的临界流速;哥氏力对不锈钢和钛合金2种管材燃油管路固有频率的影响很小;相同壁厚管路,外径越小,流固耦合对固有频率的影响越大。

Analysis for Natural Frequencies of Pipe Conveying Fluid Considering Fluid-Structure Interaction

In order to analyze the effect of Coriolis force and pipe parameters on the natural frequencies, the fluid-structure coupling model of pipe conveying fluid was established using the Galerkin method, and the natural frequencies of the pipe were obtained by the complex-eigenvalue method. Comparing with the experimental data, the analytical results were verified, which indicated that the analytical model is rational. The critical velocity of the test pipe conveying fuel was obtained, and the influence of Coriolis force and the section characteristics to the natural frequencies were investigated. It is found that the fuel velocity of the test pipe is far below the critical velocity. The Coriolis force has little effect on the natural frequencies of both the stainless steel and the titanium alloy pipe. For the pipe in the same thickness, the fluid-structure interaction has much effect on the natural frequency as the out diameter of the pipe decrease.