基于流固耦合共轨高压油管振动特性研究

Vibration Characteristics of Common Rail High Pressure Fuel Pipe Based on Fluid-Structure Coupling

为了研究流固耦合作用下共轨系统高压油管的振动特性,建立了高压油管的有限元模型。首先根据输液管道动力学方程,利用ANSYS软件分析管道附加流体质量下的湿模态特性;然后以均方根(root-mean-square)量化时程内的振动能量,研究流固耦合作用下管道不同弯头的振动响应,不同燃油脉动率、压力及激励频率对管道流致振动的影响,最后对比了共振频率下管道增设管夹前后的振动特性。结果表明:流固耦合下管道固有频率下降,在高阶模态下降率较明显,附加质量系数超0.13;不同弯头振动差异较大;振动能量与燃油脉动率呈正相关,与压力大小并无直接关系;接近自振频率下管道发生共振,振幅会急剧增大至超标;并且增设管夹后共振现象消失,振动能量下降率超90%。

In order to study the vibration characteristics of high pressure tubing in common rail system under fluid-structure coupling,a finite element model of high pressure tubing was established.According to the dynamic equation of the infusion pipeline,the wet mode characteristics of the pipeline with additional fluid mass were analyzed by ANSYS software.Then root-mean-square was used to quantify the vibration energy in the time history,and the vibration response of different elbows of the pipeline under fluid-structure coupling,the influences of different fuel pulsation rates,pressures and excitation frequencies on the pipeline’s fluid-induced vibration were studied.Finally,the vibration characteristics of the pipeline before and after adding pipe clamps under resonance frequency were compared.The results show that the natural frequency of the pipeline decreases under the fluid-structure coupling,and the decrease rate is more obvious in the high order mode,and the additional mass coefficient exceeds 0.13.The vibration of different elbows varies greatly.The vibration energy is positively correlated with the fuel pulsation rate,but not directly related to the pressure.When the pipeline is close to the natural vibration frequency,the resonance occurs,and the amplitude increases sharply to exceeding the standard.After adding the clamp,the resonance phenomenon disappeared and the vibration energy decreased by more than 90%.