Integral Design of a Turbocharger for Internal Engine Energy Saving: Centrifugal Compressor Design
Abstract Energy savings and emission reductions are essential for internal engines. Turbocharger is critical for engine system performance and emission. In this study, the engine simulation program was used to systematically optimize the engine turbocharger system performance. The velocity ratio concept was used in the engine simulation program to consider the performance impacts of the wheel diameter ratio between compressor and turbine. An integral consideration for both compressor and turbine was proposed to design the new turbocharger. An optimization process was used to design the compressor. The final designs employed Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) solvers for the performance and mechanical integrity assessments. The optimized compressor wheel has different features comparing with conventional designs. In this design, the splitter is not located in the middle between main blades; the compressor wheel exit diameter at shroud is larger than hub. The new compressor was tested on both gas stand and engine. The numerical results are fairly agreed with gas stand tests. The tests showed about 1.2% of the engine BSFC reduction without sacrifice the emission and cost. This study demonstrated that a systematic method in simulation and an integral compress design process could optimize the engine system and improve the engine performance.