Root cause analysis and countermeasures of high vibration of Sea Water Make-up Pump in large thermal power plant

摘要

In general, vertical pumps are weak due to vibration. Components of the pump are occasionally damaged by vibration induced from a defect in bed leveling, resonance and vortex flow. It is difficult to find the root cause of vibration and figure out the factors causing it. This paper will examine how to diagnose the root cause of vibration and mechanical damage problems. A method of vibration reduction of Sea Water Make-up Pump (SWMP) in thermal power plant is represented. The causes of vibration and system stability are investigated in two different ways. The causes of vibration are investigated using eigenvalues which are numerically computed by modal analysis and rotor dynamics. The stability of the rotor bearing system is checked using eigenvalues of SWMP by rotor dynamics. The results of modal analyse are compared with those of modal testing. It is a cause of critical vibration that natural frequency of SWMP coincides with the excitation frequency of unbalanced force at operating speed. A high-amplitude vibration problem happens at such resonance and thus SWMP may be damaged. This investigation shows an approach which is able to resolve the vibration problem induced in SWMP.