자동차 엔진 메인 머플러 유동해석

Abstract

This research is about the flow analysis on the main muffler in the automobile engine. I figured out the exit side noise is louder than the inlet noise in real flow situations through the comparison of the muffler’s inlet sound pressure level. I studied main muffler mainly and analyzed the flow because we knew that additional noises occur inside the muffler. In order to secure the reliability of the interpretation through GT-power, this research precedingly compared the experimental value measuring transmission loss by Two Load Method to the GT-power value simulated by the same way. As a result, the experiment and the tendency of the analysis value were secured and I chose the case with the excellent noise characteristics. Also, I analyzed the model’s flow. There should be an exact information of flow about changes of the whole flow velocity field to accurately analyze the problem of turbulent flow field inside the muffler. Accordingly, I was able to obtain related data using the numerical analysis technique by computer and was able to identify the sound intensity and the tendency of incidence by analyzing general characteristics about fluid flow. Muffler, a device for decreasing the noise from the engine in general, has a shape of rectangular box or a cylindrical shape. I should be careful about balancing noise and exhaust resistance because when we change the shape of muffler to lessen the noise, it would increase the resistance on the exhaust stream and lower the engine output. I am going to identify the exhaust resistance by the form changes of the muffler tailpipe, analyze the content related to the general characteristics of fluid flow and the noise, and find a way to improve the flow resistance in tailpipe and reduce the noise.