A new design for energy-saving volutes in centrifugal pumps

Abstract

Geometrical structures and operating performance of volutes used in centrifugal pumps are assessed in cross sections. By a volute, we mean the wetted part surrounding the impeller in a pump that converts the kinetic energy of water into potential energy. It is important to develop improved design principles and approaches for volutes to reduce hydraulic loss and increase the efficiency of pumps. However, when designing volutes, pump designers often neglect a key factor related to pump efficiency, namely, the energy loss due to the friction at the volute sidewall is directly proportional to the wetted perimeter of the cross section. In this paper, we show that the length of the wetted perimeter of the cross section is mathematically proportional to the friction loss in the volute. In addition, we present the design principles and calculation process to minimize the wetted perimeters of two kinds of cross section based on the velocity coefficient method using the same statistical data. The structures and shapes of the new cross sections are completely different from those of traditional volutes. Moreover, two different volutes with different cross sections are numerically investigated using a verified computational fluid dynamics technique. Both the head and the efficiency of the pump with the new volute are higher than those of a conventional pump under all working conditions. This paper provides a new design approach for the energy-saving volutes of centrifugal pumps.