A Study on Multistage Centrifugal Pump Performance Characteristics for Variable Speed Drive System

Abstract

Nowadays centrifugal pumps are being widely used in the commercial, industrial and power plant applications and most of pumps operated by constant speed drive system. Therefore, pump consumes a huge energy of each nation's total energy. But it could be operated in variable speed drive system which would be provided energy saving. The purpose of this study is to investigate the pump performance characteristics of the multistage centrifugal pump with the variable drive system. For this study an experimental set up of the system was constructed to achieve the centrifugal pump performances such as H-Q, η-Q, P-Q curves and operating points which interact between performance and system curves. In the variable speed drive system, a vector controlled inverter driving (variable voltage variable frequency) was installed in the experimental system. A numerical investigation also applied for getting the pump performances for the validation and reliability of the pump design development and also the pressure and velocity effects in internal flows of the pump are analyzed. For the numerical analysis, the Navier-Stokes equations were discretized by the finite volume method and two equations transport turbulence (SST) model accounts for three dimensional steady flows. In the experiment system, we also carried out system head performance of the three pumps in parallel to compare with one pump system head for its validation. In order to get the energy saving rate using the inverter control variable speed drive system instead of the constant speed drive system, it is necessary to identify the specific duty cycle of the pump operation cycle and operating system curve of the pump. Hopefully, this paper will be useful as a guide for identifying a method of implementing a variable speed drive system with inverter control in the variable flow and pressure system.