Aerodynamic Studies in the Static Components of A Centrifugal Compressor Stage

Abstract

Aerodynamic studies in the static components of a centrifugal compressor stage were conducted using the computational fluid dynamics solver FLUENT. For the simulation study, a typical centrifugal compressor stage geometry with a flow coefficient of 0.053 was chosen, The study is confined to the static components of the centrifugal compressor stage, i.e., the crossover bend (180° U-bend), a radial cascade of return channel vanes, and the exit ducting (90° L-turn). The aerodynamic performance is reported in terms of total pressure loss coefficient, static pressure recovery coefficient, return channel vane surface static pressure distribution, and stage exit swirl angle distribution. The simulated flow through the static components covered five different operating conditions of the actual centrifugal compressor stage: the design point with 100% flow rate, and the off-design operating conditions with 70%, 80%, 110%, and 120% flow rates. The standard k-ε model was used with standard wall functions to predict the turbulence. A minimum total pressure loss coefficient was observed near 80% flow rate when the average flow angle at the U-bend inlet was 24°. Better static pressure recovery was observed with 70%, 80%, and 100% flow rates. The swirl angle distribution at the stage exit was recognized as satisfactory.

The effects of the return channel geometry on the aerodynamic performance of a centrifugal compressor: A numerical study

“…Turbulence effects are evaluated using the standard k-ε turbulence model because several studies have indicated the suitability of this model for the simulation of centrifugal compressors. [34][35][36][37][38][39][40] The numerical results of the current study also verifies this finding.…”

“…Similarly, Reddy et al 24,25 compared the flow characteristics for three different models of the return system, in terms of the inlet blade angle, blade chord and blade thickness for a centrifugal compressor stage with the flow coefficient of 0.053 at the design and off-design points. The numerical results illustrated that increasing the negative incidence on the leading edge of the vaned return channel causes fluid acceleration up to 30% chord length from the leading edge on the suction side.…”