| As the energy and environmental problem is getting more and more attention today, diesel engine is getting more and more concern for its high efficiency, good economic and emission performance. But one obvious disadvantage of it is its noise is so loud. In this paper, fan noise and exhaust noise is emphatically studied to reduce the aerodynamic noise of diesel engine, providing the solution to reduce the aerodynamic noise for manufacturer, which is of great economic and practical significance.As to the research on fan noise, it is very difficult to test the situation accurately. So simulation analysis method is mainly used here. Firstly, the generation mechanism and influential factors of fan noise is studied. Then take the axial flow fan of some diesel engine as research subject. Its Solid model is established in Catia and its CFD simulation analysis is done in Star ccm+. And experimental formula and calibration value of fan factory is adopted to verify the reliability of CFD analysis. Next by analyzing four conventional factors, the influencing rules on the fan performance are obtained. The original fan is optimal designed by analyzing these rules comprehensively.As to the research of exhaust noise, take the exhaust system of some diesel engine as research subject. The internal structure of exhaust muffler and the diameter of exhaust connecting pipe is optimal designed to reduce the exhaust noise. Firstly, the generation mechanism of exhaust noise and influential factors is introduced, the classification and common evaluation indicators of muffler is studied, and two optimal solutions are obtained. Next the tail pipe noise and back pressure simulation computational model is established in GT-Power. Select the best solution by analyzing the result of simulation. To verify the optimal solution is advisable, the tail pipe noise is tested in the anechoic chamber with hub by matching the corresponding scheme, to verify the optimal solution is advisable. |
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