Total Power Model of Flow Noise Generation from Perforated Duct Muffler Element
ZHAO Hai-jun1,3; DENG Zhao-xiang1,2; LI Pei-ran1
1 College of Mechanical Engineering，Chongqing University，Chongqing 400044, China;(2 State Key Laboratory of Automotive NVH and safety control，Chongqing 400039, China;3 Department of Mechanical Engineering, Luoyang Institute of Science and Technology, Luoyang 471023, China
Abstract：Using orthogonal experimental design method detailed structure parameters of work piece about perforated tube muffler element are determined. Flow noise regeneration is measured on the self developing test bench. Relationship model on total sound power of flow regeneration noise and structure parameter and flow velocity is established utilizing dimensional analysis, model parameters are solved making use of hyper static least square method. Significance test of the model is performed, the law of total sound power level for muffler element flow regeneration noise changing with the parameters is discussed. Result shows that the established models are all highly significant under 0.01 levels, the reducing of the perforated diameter and the perforated part length is favor of the reduction of flow regeneration noise from perforated tube muffler element, and perforated ratio and expansion chamber diameter have less effect on flow regeneration noise. After analyzing spectrum structure of flow regeneration noise, it is indicated that with the increase of flow velocity projected peak value frequency has the trend of moving to middle and high, its strength also becomes bigger. When the range of Strouhal number is from 0.2 to 0.35, there is a peak value frequency, its sound energy in the frequency accounts for about 60% of the total energy.
2011, Vol. 30 
