Experimental study of aerodynamic noise performance of improved air distributor for ships

Abstract

In ships, aerodynamic noise from the variable-air-volume fan is a common problem. This study experimentally explores the strategy of reshaping the traditional C-shaped channel structure to an L-shape to reduce noise. The noise level and resistance coefficient of the improved air distributor are analysed, and the results show that the noise of the original air distributor is 56.3 dB(A) under the rated working conditions (static pressure of 800 Pa and flow rate of 350 m3/h), which exceeds the International Maritime Organisation’s (IMO) ship noise limit (55 dB(A)). For the improved air distributor, the noise pressure level is 38.5 dB(A), the sound pressure level of high-frequency noise is reduced by 48% and the peak sound pressure level appears at 125 to 250 Hz, a frequency below the threshold of human hearing. Thus, the reshaping of the channel has a significant noise reduction effect. When the static pressure is 400 Pa and the flow rate is 100 to 500 m3/h, the sound pressure level of the improved air distributor is reduced by 29.9% to 32.2% to become less than 55 dB(A). Thus, the sound pressure level at the outlet of the improved air distributor meets the IMO ship noise standard.

Improvement of airflow uniformity and noise reduction with optimized V-shape configuration of perforated plate in the air distributor

“…8,9 Second, the sense of pleasure is also affected by the type and level of noise, which is determined by the pulsating parameters of the flow field. Similarly, noise reduction optimization [10][11][12] of typical components such as AD and sudden expansion and contraction was carried out by theoretical, experimental or numerical simulation methods, 13,14 which greatly reduced the sound pressure and proved the synergistic relationship between the pressure field and the sound field. 15 Several studies have demonstrated that the perforated plate can be used to reduce the turbulence intensity and achieve the control and noise elimination of the broadband noise of the pipeline.…”

Numerical Optimization Study of the Resistance Coefficient of U-Shaped Air Distributor

“…Guo Y et.al experimentally explored the strategy of reshaping the traditional C-shaped channel structure to an L-shape, to reduce noise. The noise level and resistance coefficient of the improved air distributor were analyzed [12]. Ran et al studied the resistance coefficient of the air conditioning pipeline at the elbow joint.…”