Improvement of internal combustion forklift exhaust muffler considering  the influence of flow and temperature fields

WANG Zhigang1, YOU Hongwu1, WENG Hao2, ZHU Fuhong3, WENG Zeyu1

(1.College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014, China;

2.Guiyang Urban Rail Transit Co., Ltd., Guiyang 550081, China; 3.The Chinese Peoples
 Liberation Army 73021, Hangzhou 310023, China)

Abstract: Aiming at the problem of an internal combustion forklift with excessive exhaust noise during high speed, the software Fluent was used to calculate the flow field inside exhaust muffler. Through the establishment of the coupling relationship between the flow field data and acoustic grid inside the muffler, the transmission losses were calculated in presence of flow and temperature fields using acoustic simulation software. According to the acoustic simulation results, the improvement and simulation of muffler were made aiming for the inadequacy of noise eliminating capability of the internal combustion forklift exhaust muffler. Finally, the exhaust noise of the internal combustion forklift was tested to verify the noise eliminating effect of the improved exhaust muffler. The results indicate that the improved exhaust muffler can make the internal combustion forklift exhaust noise decrease by 3.07 dB(A), the air flow velocity and temperature increase produce a movement to high frequency of transmission losses curve and a large offset of curve with the increasing of frequency, meanwhile the transmission losses at high frequency also rise.

Key words: internal combustion forklift; exhaust muffler; flow field; temperature field; improvement