Numerical Flow Analysis And Improvement Design Of A Turbocharger Compressor

Diesel engine is one of the most efficient and widely used power machines, and it plays an important role in energy and power industries. Turbocharger is a combined component used to increase pressure at the inlet of the diesel engines. Nowadays most ship diesels are using exhaust turbocharging. This has become one of the most effective measures to increase diesel powe,improve fuel economy,reduce exhaust emissions and decrease engine volume and weight per unit horsepower.With the development of modern diesels, the requirement for the performance of turbochargers is getting higher and higher. The overall performance of a turbocharger depends on that of its component parts. The research in this paper focuses on a centrifugal compressor, which is a core component of a ship exhaust-gas turbocharger. Numerical simulation and analysis platform was established for the compressor with CFD software NUMECA. On this basis, the internal flow of the compressor was simulated and analyzed numerically. Results indicate that its working scope is narrow and internal flow is disturbed. There exists a big vortex in the diffuser which dissipates a large amount of energy and causes low efficiency. And it can be concluded that the poor performance is resulted from improper design of impeller, although energy losses mainly occurred in the diffuser. Thus, based on commercial design software, different design parameters of impeller were optimized by trial-and-errors and a satisfactory impeller was obtained. In order to improve the working scope of the compressor, vaneless diffuser was adopted. The newly designed impeller vaneless diffuser and original volute combined a new compressor. Numerical flow analysis results show that the efficiency of the whole stage is increased by 4.09% with a much wider working scope. This paper may provide theoretical and practical reference for the design and research of ship turbocharger compressors.