Influence of operational changes of clearances in pump channels on the work of the automatic balancing device

Abstract

Automatic balancing devices are used to balance the axial force in many multistage centrifugal pump designs. Despite the obvious advantages of these devices their failure is one of the main reasons for the complete failure of the pump unit. The axial force acting on the pump rotor can be changed under pump operation in a sufficiently large range and up to several tens of tons. Usually the calculation of automatic balancing device is made under pump's operating parameters. At the same time it is possible the changing of value of the axial force generated by the automatic balancing device on the calculated parameters due to the interdependence of hydrodynamic processes in clearances of the flow part of the pump and in the clearances of the balancing device. The analysis of possible causes of the axial force value changes as a result of unbalanced pressure forces acting on pump impellers and counterbalancing of axial forces arising in face gap balancing device is presented. An improved methodology for calculating the estimation of the axial force arising in the balancing device using the example of industrial multistage centrifugal pump is proposed.