Flow Control of Radial Inlet Chamber and Downstream Effects on a Centrifugal Compressor Stage

Abstract

Radial inlet chambers are widely used in various multistage centrifugal compressors, although they induce extra flow loss and inlet distortions. In this paper, the detailed flow characteristics inside the radial inlet chamber of an industrial centrifugal compressor have been numerically investigated for flow control and performance improvement. First, the numerical results are validated against the experimental data, and flow conditions inside the inlet chambers with different structures are compared. They indicate that, in the non-guide vane scheme, sudden expansions, tangential flows and flow separations in the spiral and annular convergent channels are the major causes of flow loss and distortions, while using guide vanes could introduce additional flow impacts, separations and wakes. Based on the flow analysis, structure improvements have been carried out on the radial inlet chamber, and an average increase of 4.97% has been achieved in the inlet chamber efficiencies over different operating conditions. However, the results further reveal that the increases in the performance and overall flow uniformity just in the radial inlet chamber do not necessarily mean a performance improvement in the downstream components, and the distribution of the positive tangential velocity at the impeller inlet might be a more essential factor for the efficiency of the whole compressor.

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

“…The influence of variable geometry compressors on airflow characteristics was introduced in detail, making it possible to numerically simulate the aerodynamics of variable geometry compressors [5] with rotating guide vanes in the future. Han et al [6] conducted a numerical study of airflow characteristics in a centrifugal compressor. A comparison was conducted between the nonguide vane scheme and the scheme with guide vanes.…”

Study on the Influence of Radial Inlet Chamber Splitter Blades on the Oblique Flow Compressor Performance

“…The airflow in the new RIC was more reasonable, the pressure loss was small, and the outlet flow was more uniform. Han [22][23][24][25] calculated the flow field inside the RIC and its influence on centrifugal compressor performance by numerical calculation, and found that the flow loss caused by the RIC had little influence on compressor performance, but the outlet distortion was the main reason for the deterioration of the performance of downstream components. In addition, the aerodynamic parameters of each section inside RIC were measured in detail through experiments.…”