Objectives  In order to analyze the influence of different wear ring clearances on the output characteristics and vibration performance of a centrifugal pump, an integrative test platform of closed-circuit output characteristics and vibration performance is established to carry out experimental study.

  Methods  Taking a vertical centrifugal pump as the research object, seven groups of sealing rings with different internal diameters are designed, the power spectrum of the vibration signal from the pump body is collected using a 16-channel vibration accelerometer, and the operating characteristics of the pump under different clearance conditions are tested.

  Results  The results show that the head and efficiency of the centrifugal pump decrease with the increase in wear ring clearance, and that wear ring clearance has a greater influence on the radial balance of the single-stage double-suction centrifugal pump and further affects shaft frequency vibration intensity. When the wear ring clearance increases, the reflux increases the fluid pulsation of the centrifugal pump and causes the vibration energy to concentrate at high frequencies.

  Conclusions  The results of this study reveal the influence of the wear ring clearance of a centrifugal pump on its output characteristics and excitation force properties, and can provide theoretical guidance for the condition assessment and maintenance work of centrifugal pumps.