Analysis of airflow regeneration noise in an engine aftertreatment device and its improvement
In order to reduce the airflow regeneration noise of an engine aftertreatment device,a finite element model of the airflow regeneration noise of the post-treatment device is established using computational fluid dynamics(CFD).The intensity of the noise source is analyzed,and the maximum sound pressure level of the airflow noise is determined at the perforation in the back row of the outlet pipe.Two optimization schemes are designed:changing the perforation structure of the outlet pipe to an intubation structure and blocking the perforation in the back row,and the sound pressure level and transmission loss are compared by simulation.A comparison is made between the structure of the aftertreatment device that blocks the rear perforation and the original design by vehicle acceleration testing.The simulation results show that both optimization schemes reduce the sound pressure level of airflow noise,and do not affect the noise reduction ability of the post-processing device.The test results also show that using a aftertreatment device structure to seal the rear perforation significantly reduces noise,and the broadband noise caused by fluid flow almost disappears.The total sound pressure level of the noise decreases from 90.4 dB to 82.3 dB.
engineaftertreatment deviceair flow regeneration noisetransmission loss
NETL
NSTL
万方数据
