Hydraulic Performance and Effect on Flow Domain for Variable Outlet Angle in Mixed Flow Centrifugal Pumps

Abstract

The existing theoretical formulae to

determine the various parameter values of

pump performance are not conforming to

the degree of accuracy with experimental

values due to its complexity in geometry.

Hence an economical way to analyze the

flow domain using CFD is advantageous in

designing the real model. Parametric study

is conducted on the pump to determine the

effect of vane outlet angle (β2: 250 , 27.50 and

300 ) and convergent inlet stator on

hydraulic performance of a centrifugal

pump. The hydraulic flow domains are

modelled and meshed with unstructured

tetrahedral elements. The steady state

incompressible fluid, k-ω SST turbulence

model with coupled algorithm is considered

to solve the model. Multiple reference

frames is used for rotor stator interface.

Boundary conditions of fixed mass flow rate

with atmospheric gauge pressure and total

pressure are set at inlet and outlet

respectively. The residual convergence is set

to 0.001. Based on the analysis the Best

efficiency point (BEP) shifts towards higher

flow for the vane outlet angle 27.50 and

towards lower flow for 250 and 300 from the

designed value for the given impeller

diameter and impeller width. Also, increase

in the head developed and decrease in

efficiency at BEP is observed as the vane

outlet angle increases.