Empirical study of noise characteristics of typical centrifugal fan based on special quantities using sound intensity based method

In order to identify best treatments at noisy sources, experts must be employed special noise quantities. Sound pressure close to sources is usually dependent upon the environments, therefore it is not suitable for determining noise emission of sources. This paper aims empirically to study noise emission characteristics of a typical centrifugal fan located in different layouts based on special quantities using sound intensity based method. In Situ determination of noise emission of the fan included sound power, sound intensity and sound pressure was performed using VA – Lab designed by by BSWA according to standard methods in different locations. The results showed sound power spectrum of the fan is relatively high and contains predominant diceret tone in 250 Hz equal to 83.5 dB. The sound powers of the fan were similar in the different locations. However, notable difference exists in the sound intensities of the fan in the different layouts which are near to the values calculated by theorical equation. In order to determine the optimum locations for studied centrifugal fan, sound intensity could also accurately describe the effects of adjacent surfaces on the centrifugal fan noise than sound pressure. This study empirically showed sound power of fan is independent of the environments and can help us for evaluating noise controls at fan elements. The results confirmed the sound power and the intensity were excellent quantities for characterizing noisy sources as centrifugal fan compared with the sound pressure. These results presented the detail of a scientific approach for analyzing noise in workrooms.