Research On Low Noise Control Technology Of Engine Exhaust

River-sea ship with a half-way transshipment,directly from the port of shipment by sea and inland waters of two arrived at the destination the way to get a broad market prospect.However,as more stringent noise control bills are implemented,shipboard radiated noise level control becomes an important issue.?Code on Noise Levels on board Ships?in the new requirements,so that the original downturn in the ship industry is facing new challenges,more ships will be less than the new noise requirements of the new noise is difficult to operate.In this paper,the exhaust noise of 6320ZCd-2 diesel engine is used as the object,and the impedance complexing muffler with better noise reduction is designed by numerical simulation.Therefore,the research on the current situation and development trend of muffler at home and abroad,the study of exhaust noise mechanism,the design of muffler design,the acoustic characteristics of resistance and resistive muffler,and the structural design of impedance composite muffler are studied.The main tasks include:(1)The research on the mechanism of engine exhaust noise is carried out to understand its main noise composition and frequency characteristics.The analysis method of acoustic characteristics of muffler is studied and the transmission loss is selected to judge the effect of noise reduction of muffler.(2)Using LMS Virtual.lab software to carry out the acoustic special research of the resistance muffler,the transmission loss of the expansion tube and the perforated tube muffler,the sound pressure level response of the inlet and the outlet and the internal sound pressure distribution are obtained.The control variables and comparative analysis were used to study the determinants of the performance of the expansion tube and perforator muffler.(3)Simulation of resistive muffler model,to study its acoustic characteristics.The influence of variable factors on the acoustic properties of the resistive muffler was analyzed by the analysis of resistive muffler with different acoustic materials,different thickness of sound absorbing layer and different protective layer of perforated tube.(4)Using GT-power to calculate the 6320ZCd-2 diesel engine of river-sea ship,and analyze the data of engine exhaust noise at different speeds.Combined with the resistance and the acoustic performance of the resistive muffler,and the acoustic characteristics,considering the actual exhaust temperature and the influence of the air flow,the impedance composite muffler is designed and the noise reduction effect is predicted.