A Feasibility Study of Maximizing Radial Flow Compressor Performance by Hierarchy Optimization Using Individually Optimized Components

Numerous published articles focus on optimizing individual components of radial flow compressors to achieve enhanced performance. These components include the impeller, diffuser, and volute. However, there is a limited number of published papers studying the combined performance of individually optimized components working together. This article presents a hierarchy optimization approach conducted on a turbocharger compressor, composed of two or three individually optimized components including two optimized impellers, one vaned diffuser and one optimized volute, each with distinctive optimization method. The article also reports the resulting improvements in pressure ratio and overall isentropic efficiency of the machine, by means of investigations of nine different compressor configurations, including the original design. Experimental tests are performed at several rotational speeds and different mass flow rates to generate compressor performance maps. To simulate the compressor flow field, a three-dimensional steady-state compressible turbulent flow simulation code is employed and evaluated with experimental data. The results show that a configuration using an optimized impeller, vaned diffuser, and an optimized volute, improves efficiency and pressure ratio up to 11.3% and 16.5%, respectively, which are significant enhancements and important achievements. A detailed examination of the flow field reveals that in this particular configuration, pressure fluctuations at the impeller exit decrease by 71%, and the average pressure at the impeller exit increases up to 46% compared to the original design. Furthermore, flows in the impeller passages become more uniform, with limited separation regions near the trailing edge of blades.