Aerodynamic performance analysis and optimization of key parameters in a centrifugal compressor
Abstract
Centrifugal compressors are key pressurization components in micro gas turbines and turbocharging systems, and their aerodynamic performance directly affects overall efficiency and operational stability. Under high pressure ratio operating conditions, the internal flow field is characterized by inherently three-dimensional and complex flow phenomena, wherein variations in geometric parameters can profoundly modulate the evolution of flow structures and the concomitant aerodynamic performance. Accordingly, proceeding from the underlying internal flow mechanisms, this study presents a systematic investigation into the effects of key geometric parameters on compressor aerodynamic behavior, and undertakes an optimization design predicated upon the correlation mechanisms linking flow characteristics to performance response. A multi-parameter analysis and integrated optimization approach is adopted based on the Concepts NREC and NUMECA platforms to systematically investigate the influence of key geometric parameters, including hub ratio, tip clearance, blade backsweep angle, diffuser exit width ratio, and splitter blade number, on compressor performance. The results indicate that reducing the hub ratio can suppress secondary flow within the impeller; an appropriate tip clearance balances leakage and friction losses; decreasing the absolute value of the backsweep angle improves outlet flow uniformity; reducing the diffuser exit width ratio enhances diffusion capability; and a proper configuration of splitter blades reduces the aerodynamic loading on individual blades. After optimization, the isentropic efficiency increases from 70.80% to 78.05%, and the pressure ratio improves from 8.113 to 8.449, with a more uniform flow field and significantly reduced entropy generation. This study systematically reveals the effects and coupling mechanisms of multiple geometric parameters on the aerodynamic performance of centrifugal compressors, providing guidance for the refined design of high-pressure-ratio compressors.