A Look at Compressor Impeller Technologies for Turbochargers Focusing on Surge Mitigation

With rising fuel costs and new emissions standards for automobiles, automotive manufacturers are turning to new ways to decrease engine size and emissions while still maintaining high power operation. This can be accomplished through the use of turbochargers. The aim of this study is to analyze what is currently being done with turbocharger compressor technology to meet these requirements. This analysis will focus on different impeller blading designs including splitter bladed impellers, tandem bladed impellers, and tandem bladed impellers with a casing blade. There are different advantages associated with each impeller design. The tandem bladed impeller designs are shown to have decreased efficiency and pressure ratios as compared with the backswept and/or splitter bladed designs. It is also shown that the operating range is increased with the tandem design due to a lower surge margin. Further analysis needs to be conducted on refining the tandem bladed and tandem bladed with a casing blade designs to truly see if these designs have the potential for greater performance improvements.