Optimized design and performance analysis of a high-pressure radial turbine for energy recovery applications

Single-cylinder direct-injection engines suffer significant exhaust energy losses; however, designing efficient radial turbines for such systems requires a physical characterization of pulsating flows and thermal stresses. This paper investigates the design and performance of a 500W high-pressure radial turbine for waste energy recovery for a single-cylinder engine. The main objective of this study is to optimize the turbine's dimensions and efficiency for capturing exhaust energy upstream of catalytic converters in internal combustion engines. Employing a two-stage computational approach, numerical modeling first established key geometric parameters, including a 19.3 mm inlet radius, 5.1 mm leading-edge length, 72° inlet angle, and 0.7 outlet radius ratio, followed by CFD simulations in ANSYS CFX using a 212,212-element single-passage mesh at 50,000, 70,000 rpm and 90,000 rpm, and 800 K inlet temperature. The optimized turbine demonstrated peak efficiency of 67% at a mass flow rate of 0.005 kg/s, revealing that systematic numerical optimization significantly enhances energy conversion efficiency. These results provide critical insights for developing compact, high-efficiency turbines for exhaust energy recovery systems, advancing waste heat utilization technology.