CFD Flow Field Assessment and Performance Map Generation of A Turbocharger Radial Turbine Attempted to Be Matched With a Downsized Diesel Engine

Abstract

The present paper aims to propose an efficient methodology to match aerodynamically a 1.5 l, three cylinders downsized Diesel engine, with a selected turbocharger to boost its performance based on 1D codes and CFD simulation. In this aspect, a radial turbine’s stage was sized and designed applying 1D preliminary design in-house codes. Then, a CFD simulation was established to investigate the flow field through its components and to predict its performance. Based on the simulation data, a turbine’s map was generated via gas-dynamic simulation software. On the other hand, a turbocharger compressor was selected from a database. Therefore, the performance maps of the designed turbine and the selected compressor were matched with the engine simulation model. From the findings, the new turbocharged engine developed an operating area far from the compressor limits at the entire engine speed range, with a surge margin of 23.37% at the engine rated power. The engine thermal efficiency, brake specific fuel consumption, compressor and turbine isentropic efficiencies measured on the new turbocharged engine expressed an enhancement at the engine rated speed of about 6.79%, 6.36%, 19.91% and 3.86%, respectively, compared with the original engine. Furthermore, maximum deviations of 7.43% and 0.47% were measured between the new and the original turbocharged engines in terms of in-cylinder pressure and temperature, respectively, which guarantee the engine’s thermodynamic strength. Finally, the developed methodology reported satisfactory results in terms of the engine’s secure functioning and predicted performances, which can be considered as an important basis before initiating any detailed conception.