Design And Research Of Exhaust Muffler For Single-cylinder Diesel Engine Based On The Principle Of Split-stream Rushing

Diesel engine noise is large,which has a serious impact on the physical and mental health of the staff and the surrounding environment.The most direct and effective way to reduce diesel engine exhaust noise is to install exhaust mufflers,but the performance of the mufflers designed in the past was usually improved by sacrificing the diesel engine exhaust back pressure,which could not meet the requirements of good muffling performance and low exhaust resistance at the same time.Therefore,this thesis proposes to design and research a new type of muffler with good comprehensive performance by hierarchically coupling the split-stream rushing muffler unit with the traditional resistant perforated muffler unit.In this thesis,by taking the single-cylinder diesel engine CG25 as the prototype,its exhaust noise characteristics firstly was determined by testing the exhaust noise of this diesel engine,and then determined the initial model of coupling structure of the new muffler by combining the muffling characteristics of different muffling structures.Secondly,the acoustic performance of the new type of muffler was simulated and the influence of different structural parameters of the perforated disabled unit on the loss of the muffler was analyzed in acoustic software LMS Virtual.Lab determined the optimal parameters combination of each structured perforation muffle unit.Then by use the software of Fluent,the air power performance of the new muffler was simulated and the effects of different structural parameters of the perforated disabled unit on muffler pressure loss was analyzed.The optimal parameter combination of each structured perforation muffle unit and the coupling structure of the new muffler were determined based on the analysis of the internal flow of the new muffler.Finally,the novel muffler and the original muffler were compared,which proved that the acoustic performance and aerodynamic performance of the new muffler were better than the original muffler,and the comprehensive performance was improved,which has laid a foundation on developing the new muffler for the diesel engine.