Research For A Mixed-flow Turbocharger Of HP60Series

Energy conservation is a hot research field in the field of engine. Due to the characteristics of improving the dynamic performance, reducing fuel consumption and reducing emissions, turbo technology has become an indispensably crucial part of engine. Aiming at the development needs of the engine technology in the present stage, combined with experience and data in practical work, a high-performance mixed-flow turbocharger was developed and a complete method was summed up, which makes the design of turbo more simple and convenient.The main work and conclusions in this paper are as follows:(1) On the basis of searching literature, the advantages of mixed-flow turbocharger was demonstrated, simultaneously the fact that turbine performance is a key factor affected engine performance was proved.(2) Aiming at developing turbocharger for a4.7L diesel engine of a domestic company, by the one-dimensional calculation method, critical parameters such as pressure ratio and flow were obtained. By the way of quoting load factor and flow coefficient, and combined with experience, one-dimension size of the turbo was reasonably obtained, and four forms of the structure of mixed-flow turbo were proposed.(3) Through the method of CFD, the turbo model was builded up by software Numeca. By the application of software CFView, four kinds of the curved surface distribution of turbo characteristic were analyzed such as streamline distribution, Mach number size, static pressure distribution, static temperature distribution and entropy distribution, in which the curved surface included inlet and outlet sections and pressure surface, suction surface, etc. The results show that turbo of constant inlet incidence angle has the best Mach number distribution on the turbo outlet section, simultaneously pressure distribution is the most uniform, while decreasing the number of blades has a great effect on flow and resulted in the uneven pressure distribution. Although the drop of temperature is not obvious, the entropy distribution is uneven and the efficiency of turbo is impacted greatly. (4) By the results of CFD calculation, characteristics diagram of flow and efficiency of the turbo were plotted. The results of comparison show that the turbo of constant incidence angle has higher flow and efficiency than the turbo of constant inlet angle; to some extent decreasing the number of blades can increase the flow, however, it results in a large decline in efficiency which causes the overall poor performance of the turbo; increasing the axial length of the turbo could increase the flow, but the efficiency would also fall. It follows that turbine B had optimal performance of all aspects and is named HP60mixed-flow turbocharger.(5) By the method of test, the results of CFD calculations of turbo characteristics were analyzed and compared, the results showed that the results of calculations are basically consistent with the experimental data. Therefore it indicates that CFD analysis is an accurate and efficient design tool for obtaining diagrams of turbo characteristic, which has important practical significance not only for the selection and matching of turbocharger but also for optimizing the design of turbo.