The Analysis of Flow Field in a Scroll for the Turbocharger of Truck Engine
|Course||Power Machinery and Engineering|
|Keywords||Volute Three-dimensional flow field CFD simulation|
Car with exhaust turbocharger widespread adoption the a bladeless centripetal turbine volute, volute performance has great influence on the performance of the turbocharger. Reasonable design volute flow loss, even volute nozzle exit airflow distribution, and impact of airflow into the impeller, volute reflux, swirl, sudden expansion phenomenon, can effectively improve the efficiency of the turbocharger. But currently volute design is still based on the assumption of one-dimensional flow, that the nozzle outlet flow field along the circumferential direction evenly distributed, using the empirical formula to estimate fluid loss. Volute cross-section of complex shape and airflow sticky, in fact the volute flow of three-dimensional unsteady. Since the viscosity of the gas will be generated in the inner wall of the volute of the flow of gas in the boundary layer, the boundary layer along the volute and the development, in the the volute flow channel to produce a blocking effect, resulting in the flow of the outlet stream of the nozzle, the angle of attack etc.. Home and abroad on the basis of the volute flow field analysis, proposed a new automotive turbocharger volute flow field method takes into account not only the course of study the the volute flow field of engine operating conditions. the volute flow field, and consider the impeller field volute flow field. Firstly, with three-dimensional graphics software PRO / E volute flow field for the establishment of the CAD model, then PRO / E model is saved into the stp format import GAMBIT meshing Software, mesh generation and the establishment of the boundary model. Dimensional unsteady flow field within the volute FLUENT software simulation research volute inlet mass flow rate, temperature and pressure with the engine operating conditions change, and then in a variety of engine operating conditions The volute stream flow of the venue. By analyzing the volute nozzle outer pressure and velocity distribution is uneven, so the volute improved. AVL BOOST software for a certain type of diesel engine modeling and numerical simulation of their work process, validate and test data, resulting in the turbine inlet export changes with the crank angle of the engine exhaust pressure and quality of boundary conditions, The boundary conditions for non-steady-state calculation. Volute flow field analysis of the original machine basis, impeller field the volute flow field, nozzle width of the flow field in the degree of reaction of the different engine operating conditions of the turbine; next way valves to open and shut the the volute flow field; preliminary analysis of the unsteady viscous flow field in the volute.