Analysis of Fluid-Structure Coupling Vibration Characteristics in the Exhaust Manifold of a Pressurized Water System

In recent years, structural failures caused by pipeline excitation have frequently occurred during the operation and commissioning of multiple pumped storage power stations under the condition of backwater exhaust. These failures often result in the exhaust pipelines detaching from their fixed positions or even breaking and deforming within the drainage corridor. To investigate the primary and secondary factors contributing to pipeline vibration, a fluid-structure coupling simulation study was conducted on the exhaust pipeline under the backwater exhaust condition of a pressurized water system at a pumped storage power station. The results show that valve operations can cause pipe clamps to fall off, significantly reducing the natural frequency of the pipeline. When the clamp at the pipeline outlet fails, the natural frequency of 2.79 Hz can easily resonate with the pressure pulsations at the exhaust manifold outlet (with dominant frequencies of $1.1 \mathrm{~Hz}, 1.9 \mathrm{~Hz}$, and 3.8 Hz), leading to irreversible structural damage to the pipeline. It is recommended to install concrete weights at the outlet and bends of the exhaust manifold to stabilize the constraints in the X, Y, and Z directions.