Influence of Rotational Wall of Axial Inlet Device on Velocity Distribution at Impeller Inlet

Abstract

The goal of the article is to identify the influence of geometrical parameters of the axial inlet device, presence of its walls rotation and the pump flow rate on components of the absolute velocity distribution at the impeller inlet.
A numerical simulation in the software ANSYS CFX and analysis of liquid flow structure of a double entry centrifugal pump were carried out. The axial inlet device is shaped by cylindrical and diffuser section, which includes fairing in front of the impeller. Four models of the axial inlet casing were researched.
In the analyzed variants of geometry of the axial inlet device, structure of absolute velocity distribution component is similar. Rotational speed of 1450 rpm of the rotational walls of the axial inlet device compared to fixed walls affects the change of distribution of an axial component of the absolute velocity more than circumferential. Introduction of sudden expansion at the impeller inlet reduces the average value of the circumferential velocity and improves the axial velocity components distribution. Maximum and average value of the axial component of the absolute velocity and its unevenness in cross-section of the intake reduces while reducing the pump flow rate.