A Passenger Car Exhaust System The Analysis And Research Of The Flow Field

Car-ownership has rapid growth with the continuous progress of the process of industrialization and the continuous development of auto industry and the people’s living standard unceasing enhancement. But more and more cars brings a lot of problems to the society, such as air pollution, noise pollution, energy consumption, etc. Automobile exhaust system, as an important parts of the car, in addition to control exhaust pollution and reduce the exhaust noise outside, also affect the automobile dynamic performance and fuel economy. So its design should meet these requirements. But the traditional design method is time-consuming, the theoretical analysis method and the calculation object is too abstract and simplified. Even so it’s also hard to get analytic solution. CFD method, overcomeing their weakness, plays an important role in the development of the exhaust system design process.Combined with the actual project, this paper based on a passenger car’s new exhaust system of hot end, cold end and the whole flow field, build the modeling and calculat analysis, and study exhaust back-pressure of the exhaust system.This paper first briefly introduces the exhaust system numerical simulation research development present situation, and some of the basic theory of CFD methods. Then the formulae of exhaust system hot end and cold end model, calculation, and according to their flow field of velocity field, pressure field, temperature field, streamline, turbulence and analysis to verify the rationality of the design, and determine the oxygen sensor installation position and tail pipe nozzle style, optimize the silencer of perforated pipe and perforation plate. Base on this summing up some applications using in exhaust system design out with the CFD method. Finally, the simulation results of exhaust back pressure compare with test results,and verify the CFD numerical simulation credibility.In this paper, the research methods using in the exhaust system flow field analysis,and some experience summarizing in the course of the study, can provide reference for the future of the exhaust system design and other similar products designed.