Noise Reduction of Air Conditioning Electric Railway Cabin.

The development of electric railway train has been growing rapidly in the last few years. Comfort is one of the important aspects in electric railway cabin, including the acoustic comfort. İn this paper, noise reduction efforts for air conditioning system of electric railway trains are discussed. Air-borne noise and structure-borne noise are considered while finite element analysis is used to study the contribution of each path to the total sound pressure level found in the passenger area. The air-borne noise control is realized by using the acoustic liner on the internal wall of the ducting where fibrous porous absorbers are used. This approach decreases the sound pressure level as much as 29.3 dB. Meanwhile, the structure-borne noise is reduced by placing a set of a parallel stiffener at the ducting wall. This approach can reduce the sound pressure level up to 28.9 dB at low-frequency range. Combining both of the acoustic liner and stiffener altogether can reduce the sound pressure level up to 37.1 dB by which the overall sound pressure level at passenger area is around 51.2 dBA. [ABSTRACT FROM AUTHOR]