Design Of The System For Test Muffler’s Transmission Loss And Study On The Transimission Loss Performance

For the acoustic performance of materials and mufflers,testing with a station tube is currently widely used,but the current wave-based tube test system for the test of mufflers is considered to be an internal ideal air flow muffler,the test method is a double load method.However,the current test system can not test the loss of muffler transmission under different air flow speed conditions.Therefore,for mufflers under different speed air flow conditions,in order to accurately evaluate the transmission loss performance of mufflers,it is necessary to test the mufflers by using the dual-sound source method.This thesis provides a new method for testing the transmission loss performance of mufflers.The following studies were carried out on the performance test system for the flow loss of mufflers:Study on the overall scheme: This thesis provides a new flow-based wave tube test system for the test of the performance of the muffler transmission loss according to the dual-sound source method.On the basis of studying the performance of air flow to muffler transmission loss,the two-acoustic source stationtube test system and method are introduced,and the transmission loss measured by the dual-load station tube test system is compared to the different airflow velocity on the loss performance of the muffler transmission.The design of a two-source testing system for a standing-wave tube.The twin-load standing-wave tube test system can not measure the transmission loss of the silencer when it is out of time.On the basis of the twin-load standing-wave tube test system,the position of the sound source was rearranged,and the structure of the standing-wave tube was modified by adding the air source.A muffler is designed to match the test system of standing wave tube with flow,and the flow field inside the muffler is simulated by modeling and simulation,and the flow field data inside the muffler is obtained.Then the transmission loss performance of the muffler under different flow speeds is simulated again.The reliability verification of two-source standing-wave tube system.For dual source method of standing wave tube system under the condition of different air velocity for the muffler transmission loss test reliability problems,for the optimized design of standing wave tube structure acoustic field simulation,and the acoustic pressure data extraction,data in Matlab formula,after get the formula to calculate the transmission loss curve,and compare the simulation data to verify that the double standing wave tube system,the feasibility of the sound source method,and the mismatch of standing wave tube system calibration and error analysis.