Novel IGV Designs for Centrifugal Compressors and Their Interaction With the Impeller

Abstract

In centrifugal compressors, variable inlet guide vanes (IGVs) are used to control the mass flow rate with negligible change in pressure ratio and shaft speed. The efficient operation of IGVs is limited to the range of aerodynamic stability of their vane profiles. Thin symmetric profiles, which are usually used, tend to exhibit flow separation already at low setting angles, resulting in a rapid decrease in the global efficiency. Three different guide vane profiles, including a symmetric reference profile, a two-piece tandem profile with a variable angle, and an s-cambered profile, together with two auxiliary profiles, were considered. These variants were numerically and experimentally investigated at different setting angles, covering negative and positive inlet swirls, and at different operating points. The results show that tandem and s-cambered vanes have superior aerodynamic performance in comparison with the symmetric reference profile and extend the operating range of the compressor over which the efficiency remains high. The tandem profile shows better aerodynamic performance than the s-cambered profile at negative inlet swirl, while the asymmetric s-cambered profile offers an extended range of high efficiency at positive preswirl. Considering manufacturing requirements and cost, the s-cambered profile is preferred for applications with positive preswirl.

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

“…An alternative approach is the application of Inlet Guide Vanes (IGVs). A positive vane angle produces preswirl in the direction of impeller rotation and, thus, reduces compressor work at a given revolutions‐per‐minute (RPM) …”

“…Early experimental and computational fluid dynamics (CFD) studies 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, unsteady interactions between the IGVs and the impellers, pressure fluctuations at large IGV angles, and the effect of IGV geometry . A review of preswirl in from IGVs can be found in the work of Liu et al…”

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

“…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. Mohseni et al [3] presented three different novel IGVs designs for centrifugal compressors and the results showed that the s-cambered profile was preferred for applications with positive prewhirl. Cui [4] and Oro et al [5] focused on the unsteady flow for centrifugal compressors with inlet guide vanes, and analyzed the unsteady flow structures, periodic interaction, and wake transport.…”