Influence of Pulse Characteristics on Turbocharger Radial Turbine

Abstract Turbocharging has been demonstrated as a key technology to enhance fuel efficiency in the automotive field that faces increasingly stringent emission regulations. Due reciprocating engine, pulsating flow feds turbocharger turbine, which experiences conditions far from continuous scenario. In this work, effects of characteristics mass pulse, parameterized through amplitude, frequency, and temporal gradient, are decoupled studied via unsteady computational fluid dynamics calculations under on-engine operating conditions. First, model is validated based on comparisons with experimental data gas-stand Then, effect each parameter exergy budget assessed by considering ±10% variation respect baseline pulse. The other factors defining (e.g., flow, shaft speed, inflow exergy) kept same baseline. adopted approach enables completely isolate contrast previous literature studies. Based results observed, pulse amplitude identified primary affecting hot-side system response terms turbine performance, heat transfer, entropy generation, while frequency gradient show smaller influence compared it. As increases, work reported improve up 9.4%. Smaller variations otherwise observed for analysis. With 10% increase registered 5.0%, percentage reduction leads an equal 3.6%.