Studies of the flow of air in a mixed-flow pump using numerical simulations

Abstract

This article presents an investigation of the three-dimensional (3D) turbulent flow through the impeller passages and surroundings of a mixed-flow pump. Rotating passages of turbomachinery contain some very interesting and complex fluid flow phenomena. The model tested has five impeller blades mounted on a conical hub and nine stator blades in a diffuser which brings the diagonally outward flow back to the axial direction. Numerical calculations of the unsteady flow were carried out with the code Fluent, using air as the working fluid. Three models have been applied for turbulence closure: standard k-epsilon, renormalization group k-epsilon, and Reynolds stress model, using conventional wall functions near solid surfaces. For this transient 3D computation, the numerical grid has been decomposed into eight separate regions in order to process these in a parallel cluster of desktop computers. The results obtained show entirely reasonable correlations with previously published experimental data, as detailed in the performance curve comparisons and also in the numerical and experimental flow fields. These outcomes confirm that such a complex transient phenomenon may be reasonably captured by means of a commercial computational fluid dynamics code.