Numerical Analysis of the 3D Swirling Flow in Centrifugal Compressor Volutes

Abstract

The improvement of centrifugal compressor performance and the control of the radial forces acting on the impeller due to the circumferential variation of the static pressure caused by the volute require a good understanding of the flow mechanisms and an accurate prediction of the flow pattern inside the volute. A 3D volute calculation method has been developed for this purpose. The volute is discretized by means of hexahedral elements. A cell vertex finite volume approach is used in combination with a time marching procedure. The numerical procedure makes use of a central space discretization and a four step Runge-Kutta time stepping scheme. The artificial dissipation used in the solver is based on the fourth order differences of the conservative variables. Implicit residual smoothing improves the convergence rate. The loss model implemented in the code accounts for the losses due to internal shear and friction losses on the walls. A comparison of the calculated and measured results inside a volute with elliptical cross sectional shape reveals that the modified Euler solver accurately predicts the velocity and pressure distribution inside and upstream of the volute.

Influence of the volute on the flow in a centrifugal compressor of a high-pressure ratio turbocharger

“…of mass flow). Expansion loss decreases up to the design point [3]. Hence, aggregate loss will increase slightly up to the design mass flowrate and spike afterwards, when the choke limit is approached.…”

“…Detailed measurements by Ayder et al indicated a very complex, threedimensional (3D) flow within the volute and gave fundamental insights for further research [2][3][4]. It is well known that the volute flow causes a rotationally non-symmetric pressure distribution in the diffuser outlet at off-design conditions: the volute acts as a diffuser at lower than design mass flow and as a nozzle at higher than design mass flow, respectively.…”

3D Unsteady Flow and Forces in Centrifugal Impellers With Circumferential Distortion of the Outlet Static Pressure

“…Future development could be the coupling of the unsteady impeller flow calculation with a volute flow calculation, such as the one by Ayder (1993), to obtain a full stage prediction program.…”

Experimental and numerical flow field investigation through two types of radial flow compressor volutes

“…Ayder et al used a five hole probe to investigate the flow inside an overhang elliptical cross section volute to give a better insight into the three-dimensional flow structure at different mass flow rate conditions [2,3]. They developed a three-dimensional volute calculation method for this purpose to predict the velocity and pressure distribution inside and at the upstream parts of the volute [3].…”

“…They developed a three-dimensional volute calculation method for this purpose to predict the velocity and pressure distribution inside and at the upstream parts of the volute [3].…”