Volume 11, Issue 2 (6-2015)                   HSR 2015, 11(2): 250-257 | Back to browse issues page

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1- Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
2- Assistant Professor, Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
3- Student of MS.c ,Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
Abstract:   (1717 Views)
Background: Ventilation systems in buildings are one of the most important sources of noise, which are spread into the surrounding environment through fans and channels or distributors. Since axial fans are used in industry very much and silencers are among ways to noice control. The purpose of this study is investigation on use of absorptive silencer in reduction Low-frequency noise Iranian axial fan.Methods: In this study, we used galvanized chanal 0.6 mm with 30*30 cm2 dimension and axial fan. Absorptive silencer as channel was designed to cross section of channel and silencers after embedded the absorber be identical together. Length of absorptive silencer was 50cm and there used mineral wool absorbent (density 80,100 Kg/m3 and thickness 5, 10 cm). To determine the sound pressure level in a chanal, two microphones are embedded that be accomplished by using MATLAB software in the one third of octave broadband and variable speeds 600-2500 rpm. We investigate amount of the reduction in absorption silencer sound filled with Iranian absorbing materials and influence of thickness and density of adsorbent material in silence. Findings: The maximum 2 dB reduction is in pressure sound level at low frequencies of designed absorptive silencer that design in the chanal surface. In this study, an increase in the thickness of the absorbent material of absorption silencer, there was a little change in the volume decreasing but with increasing density from 80 to 100 Kg/m3 better results were seen to reduce noise levels and it caused to increase noise reduction rate.Conclusion: According to data from the present study we can use silencer with 5cm thick and 100 Kg / m3 density in the reduction of sound pressure level at frequencies lower than 250 Hz in the ventilation system as an effective device. Key Words: Fan, Absorptive Silencer, Noise Reduction, Density, Thickness
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Type of Study: Research | Subject: education health and promotion
Received: 2020/07/16 | Accepted: 2015/06/15 | Published: 2015/06/15

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