回注系统耦合振动机理

Study on Coupling Vibration Mechanism of Reinjection System

针对某气田污水回注泵、管系统出现的局部管道泄漏问题,对整个回注系统进行了现场振动测量,并分别使用一维计算流体动力学程序(CFD)和三维有限元程序(FEM)对管道结构与流体流动间产生的流、固两个物理场之间的相互作用进行独立求解。将CFD计算获得的管道系统各部位流体脉动力作为载荷施加于FEM计算模型中,分析流体激励作用下的结构响应特性。结果表明:管道振动频率与柱塞泵的作动频率相近,多处管道的固有频率相同或为该频率的整数倍,验证了振动主要由柱塞泵的低频强脉动载荷和管道局部刚度不足共同导致。此外,通过数值分析确定了管道系统中高应力点的位置,可为工程问题的预测和改造提供有力支撑。

In order to solve the problem of local pipeline leakage in the sewage reinjection system of a gas field,the vibration of the whole reinjection system was measured,and the interaction of the fluid and solid physical fields generated between the pipeline structure and the fluid flow was solved separately by using one-dimensional computational fluid dynamics(CFD)program and three-dimensional finite element program(FEM).The fluid pulsation force of each part of the pipeline system obtained by CFD calculation is applied to the finite element calculation model as a load,and the structural response characteristics under the fluid excitation are analyzed.The results show that the vibration frequency of the pipeline is close to the motion frequency of the plunger pump,and the natural frequencies of many pipe segments are the same as this frequency,or the integer multiples of it,which verifies that the vibration of the pipeline is mainly caused by the low-frequency strong pulsating load of the plunger pump and the insufficient local stiffness of the pipeline.In addition,the location of high stress points in the pipeline system is determined through numerical analysis,which can provide strong support for the prediction and reconstruction of engineering problems.