Study And Analysis Of Generator Noise And Its Control

Abstract

Noise levels associated with diesel generators often exceed local codes and city ordinances, not to mention personal comfort levels making noise study a necessity. Noise propagating from the engine, generator, radiator fan, turbo charger and even from the muffler casing produces a combined effect. Diesel generators are used very commonly in shops, offices and homes today in order to supply power during power shutdowns. These generators emit very high levels of noise, in addition to noxious air emissions. Exposure to noise causes detrimental effects on neuroendocrine, cardiovascular, respiratory and digestive systems. Chronic exposure to noise causes fatigue and interferes with concentration, thus reducing work efficiency. All the effects produced by generator noise depends on acoustic power of the generator .Acoustic power gives the information that how large the source of noise is and also helps to compare the noise radiated by generators of same type and size, whether a machine compiles with a specified upper limit of sound emission. In this measure the Acoustic Power of Diesel Generator was measured with the help of Parallelepiped method after measuring the Sound Pressure Level at 17 Grid points. Further frequency Spectrum was also obtained at three typical locations to obtain the peak frequencies at different load conditions and locations. An attempt has been made in this work to study the effect of various noise controls measures in reducing the Generator Noise. In this regard an acoustic enclosure was functionally designed and polyurethane form was use to line the surfaces of the enclosure. The effects of adding only silencer, only enclosure, enclosure with silencer, enclosure iii with silencer and inlet outlet duct were studied. Thermal consideration taken into account by using a cooling fan and its noise was reduced with help of partial barriers. Finally noise contour also obtained around the generator with enclosure at six different heights to get an idea of directivity of the noise pattern around the Diesel Generator Set and effectiveness of different noise control measures.