Flow measurement and simulation of a radial inlet for centrifugal compressor

Abstract

This paper presents an experimental and numerical research on the internal flow of a typical radial inlet for centrifugal compressor. Detailed flow measurements were carried out with five-hole probes, consisting of 106 sampling holes and 2178 measuring points. Automatic calibrating and measuring systems, which made the probe calibrations, measurements and data acquisitions controlled by computer, were developed and used to accelerate the flow measurements. Since separations and vortices in the radial inlet were not able to be accurately measured by five-hole probes, numerical simulation was adopted to assist in the flow analysis of the radial inlet in the present study. The investigation indicated that there were five main flow separations and vortices in the present radial inlet. Four of them were generated in the plenum, making the plenum the primary cause of the flow loss and the major factor of the flow distortions in the radial inlet. The last flow separation was generated on the inlet side of the flange at the 90° turning and extended to the exit of the axial duct. Besides, the symmetrical tangential flows in the radial inlet made positive and negative yaw angles with absolute value up to over 15° distributed in the tangential direction of the radial inlet’s exit, which will probably increase the incidence loss in the blade passages and negatively affect the work capability of the impeller. Based on the flow analysis and discussions, preliminary suggestions are proposed to provide references for the improvements of radial inlet.

Numerical study on the effect of radial inlet chamber on the performance of oblique flow compressor

“…Koch [13] and Flathers [14,15] added shunt vanes to the RIC and found that the flow loss increased but the outlet uniformity improved. Han [16][17][18] measured the flow field in the RIC in detail and found that the large number of vortexes generated by airflow and flow separation were the core reasons for flow loss and outlet distortion.…”

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.…”

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

“…Michelassi et al [21] and Pazzi et al [22] used a combination of experiments and numerical simulations to study the scale models of radial inlet chambers without the influence of downstream impellers, and the distributions of the velocity magnitude, flow angle and loss coefficient at the outlet of the inlet chamber were obtained and analyzed. Han et al [23,24] conducted a large-scale flow measurement on the main sections in a radial inlet chamber, including the inlet and outlet of the chamber, the intake channel's outlet and the spiral channel's outlet. The measurement was composed of more than 900 testing points on the four cross-sections, and the detailed distributions of the flow parameters inside the radial inlet chamber were first published in the open literature.…”