Ailure Mechanism Analysis And Diagnosis Method Study About The Failure To Cause Performance Degradation Of The Multistage Centrifugal Pump

Multi-stage centrifugal pump was widely used in process industry as a kind of fluid machinery. Its efficiency directly affects the economic benefit of production. This paper was aimed at the phenomenon that the operation efficiency of the multi-stage centrifugal pump is low and the energy loss is serious, the reasons for the decline of efficiency were analyzed. The four common faults of blade breakage, impeller blockage, cavitation and seal ring wear were selected, the failure mechanism of these faults was analyzed. A fault diagnosis method based on the vibration parameters of multi-stage centrifugal pump was presented. The wear monitoring of the seal ring of multi-stage centrifugal pump was verified. This method was used to guide the maintenance, reduce the energy loss and improve the economic efficiency. The main contents of this paper include the following aspects.1) The factors affecting the operation efficiency of multistage centrifugal pump were analyzed. The four common faults of blade breakage, impeller blockage, cavitation and mouth ring wear were selected to simulate their flow field,Calculate the pressure and velocity distribution. Analysis of the reasons for the decline of the efficiency of the four fault conditions.2) The vibration characteristics of four common factors affecting the operation efficiency of multistage centrifugal pump were analyzed. The reason for the decline of efficiency was diagnosed by vibration characteristics when the operation efficiency of the multistage centrifugal pump was decreased. This method was used to targeted maintenance and improve the efficiency of maintenance.3) The efficiency of different seal ring clearance was calculated by numerical simulation. The curve of efficiency varies with seal ring wear quantity was fitted,the fitting curve was used to anti thrust ring wear. The monitoring of seal ring wear was verified. Through this method, the wear state of the ring was evaluated.4) In view of the above research results, multi stage centrifugal pump test bench was built,faulty components were manufactured. Vibration and process value of the key measuring points under different working conditions were collected. The experimental and numerical simulation results are compared. The feasibility of the method of monitoring the wear of the mouth ring and the reliability of the fault diagnosis method were verified.