Experimental and numerical analysis of the unsteady influence of an inlet guide vane

Abstract

The unsteady inlet guide vane (IGV)–impeller–diffuser interaction in a centrifugal compressor is investigated numerically and experimentally under different IGV prewhirl angles. The influence of IGV prewhirl angle on the flowfield and the unsteadiness of the impeller and diffuser are studied, and the mechanism of the unsteady IGV–impeller–diffuser interaction is explored. Results show that quite fair quantitative agreements are achieved between the predicted and measured flowfield. The IGV wake can decrease the unsteadiness on the impeller and diffuser, and the reduction of the unsteadiness caused by the IGV is a function of the IGV prewhirl angle. The unsteadiness in the diffuser with negative IGV angles is larger than that for positive prewhirl angles. The low-frequency oscillations inside the flowfield are induced by the IGV. When IGV prewhirl occurs, the basic frequency of the unsteady flow in the vaneless diffuser is mainly half of the blade passing frequency of the impeller. In practice, the IGV prewhirl angle can be adjusted to avoid unsteady vibrations in some off-design conditions, with reliability and performance improved simultaneously.

Numerical investigation of influence of inlet guide vanes on unsteady flow in a centrifugal pump

“…1 Many works have been carried out to investigate the influence of IGVs on energy performance, 2,3 internal flow field, 4,5 and unsteady interaction 6,7 for centrifugal compressors.…”

A 1D mean line model for centrifugal compressors with variable inlet guide vanes

“…Both experimental and numerical approaches have been used to study compressor flow, with and without IGVs. Both can give valuable insight; however, both have their limitations.…”

“…Early experimental and computational fluid dynamics (CFD) studies 4,6 showed that introducing preswirl increases the efficiency at lower mass flow rates and improves the surge limit. More recent studies have applied CFD simulations to investigate features such as performance, 7,8 unsteady interactions between the IGVs and the impellers, 9,10 pressure fluctuations at large IGV angles, 11 and the effect of IGV geometry. 1,12 A review of preswirl in from IGVs can be found in the work of Liu et al 13 Both experimental [14][15][16] and numerical 3,9,[17][18][19][20][21][22] approaches have been used to study compressor flow, with and without IGVs.…”

Influence of Prewhirl Angle and Axial Distance on Energy Performance and Pressure Fluctuation for a Centrifugal Pump with Inlet Guide Vanes

“…IGVs for centrifugal compressors have been thoroughly studied both experimentally and numerically. Zhou et al [1] investigated the unsteady IGVs-impeller-diffuser interaction in a centrifugal compressor, and found that the unsteadiness in the diffuser with negative IGVs angles was larger than that with positive prewhirl angles. Coppinger and Swain [2] demonstrated the test techniques and resulting analyses of the existing design of inlet guide vanes systems for industrial centrifugal compressor, and conducted some predictions of the performance of the improved IGVs system design.…”