Optimal Design Of The Structure Of Diesel Generator Muffler Based On Foamed Aluminum

As the core component of conventional power system,diesel generator plays an important role in many fields such as cars,ships and construction machinery.It brings us convenience as well as noise pollution.Nowadays,adding muffler is a common way to reduce noise.Usually,the noise’s level of diesel generator ranges from 75 dB to 83 dB in China,which is dissatisfied.Therefore,the muffler needs to be optimized continuously.In this paper,the noise spectrum characteristic of diesel generator was studied firstly.After theoretical analysis,the structure of diesel generator muffler was optimized by GTPOWER simulation.With GT-POWER program,the influences of environments,engineering parameters and data measurements were analyzed.In order to collect the original data of noise,four points sampling method was adopted.For purpose of understanding the generator’s structure,the generator was disassembled and reassembled.Subsequently,the rule of muffler design was obtained.And the final design could meet the experimental requirements.The properties of the original muffler were analyzed by theoretical analysis and the characteristics of expansion muffler were acquired.The form,the number of cavities and the practical condition of the engine were taken into consideration.Finally,the shape of muffler was determined.Researches on structure of pore,composite of steel plate show that foam aluminum has significant muffering effect on voice of high frequencies,but weakable effect on low frequencies from 63 Hz to 500 Hz.Modularization of diesel generator muffler was carried out by using GT-POWER software.Based on the result of modularization,the computer model was established accurately and the simulation was carried out corresponding.After simulation,different results of muffler design were compared.Compared to square cross section,the elliptical cross section had no difference in noise reduction effect.But the square cross section had the advantage of large-scale production.Additionally,the reverse effect of air flow and acoustic wave could reduce noise.The length of the first cavity and the length of overlapping section of endotracheal intubation had significant effects on noise reduction of low frequency and intermediate frequency.The 1/4 wavelength tube in the third cavity had better noise reduction effect than the ordinary expansion cavity.The reducing the distance between the 1/4 wavelength tube and the intersection of the director was more remarkable in noise reduction.Resistive materials could reduce high frequency noise by absorbing sound energy.Therefore,resistive material could improve the overall effect of muffler’s noise reduction.Based on the studies above,the muffler was designed in impedance composite style.As a result,the favourable effect of noise reduction was achieved.The A weighted noise’s level was reduced to final 59.7dB(the original level was 92.2dB).