Study on the Monolithic Muffler Acoustic Field Performance of the Train Air-Conditioning - Advanced Research on Computer Education, Simulation and Modeling - page 139

Study on the Monolithic Muffler Acoustic Field
Performance of the Train Air-Conditioning
Xuquan Li, Yaohua Wei, Minjie Gu, Gang Wang, and Songtao Hu
School of Environmental Municipal Engineering
Qingdao Technological University
Qingdao, China
[e-mail]
Abstract. This article take the monolithic muffler which is commonly applied
in the train air-conditioning duct as the study objection. Simulates the
monolithic muffler acoustic field performance with SYSNOISE. Gets the
internal acoustic pressure distribution. Measurements on the test-bed of train
air-conditioning duct have done and verify the correctness and rationality of
the simulation results. We get the monolithic muffler transmission loss was
obtained by simulation. It provides the basis for the muffler performance further
study.
Keywords: Train air conditioning; Monolithic muffler; Transmission loss;
noise; Simulation.
1 Introduction
The noise which is generated by air conditioning unit come into the train room
through the air conditioning duct, because the straight pipe, elbow, tee, reducer pipe
exists the air conditioning duct, the noise will arise certain natural attenuation in the
dissemination process [1]. As a lot of practices show, after the attenuation, the noise is
difficult to come to the noise limit of train indoor, which requires certain measures to
be taken on the air conditioning system for us to reduce noise, making the indoor
noise is lower than the noise limits which stipulated in the GB/T12816-2006.
At present, the main method for reducing the noise of the train air conditioning
duct is to install the duct silencers. On one hand, after installation of silencers, it is
useful for reducing the noise in the duct, but on the other hand also will increases the
resistance of air duct. So we should consider the requirement of the spot and the
impact on the system resistance when design or select the silencers.
In this paper, we adopt the method that combines numerical simulation and
experimental validation to study on the monolithic muffler acoustic field performance
of the train air -conditioning duct [2][3]. The typical structure of the monolithic
muffler is that fixes the sound-absorbing materials on the right and left wall and insert
the silencer boards which are made up of sound-absorbing materials. The muffler is
divided into a number of small uniform air flow channel, typically the thickness of the
middle silencer boards is twice the size of the sound -absorbing material on both