曲轴皮带轮气动噪声降噪分析
丁保安1，2，张晓辉1，2*，王景新1，2，张伟龙1，2，赵雪飞1，2，赵婧婧1，2
1.内燃机与动力系统全国重点试验室，山东 潍坊 261061；2.潍柴动力股份有限公司，山东 潍坊 261061
摘要：为降低曲轴皮带轮噪声，采用流体仿真软件STAR ccm+建立流场仿真模型，结合声学软件LMS Virtual lab进行皮带轮气动噪声仿真及皮带轮结构模态、声腔模态分析。仿真分析结果表明：皮带轮高速旋转时，皮带轮与齿轮室前端盖间的凹槽流速不均匀，凹槽表面产生周期性压力脉动，是皮带轮气动噪声主要噪声源；凹槽内形成相对封闭的空腔，其声腔一阶模态频率与噪声源激励频率接近，使噪声增大。采用皮带轮开孔5 mm的优化方案，与皮带轮不开孔的原方案进行气动噪声仿真和测试试验对比及验证，结果表明：对比原方案，优化方案气动噪声仿真声压级均方根约减小了4 dB，升速工况试验声压级均方根约减小2 dB；原方案、优化方案的仿真与测试数据基本吻合，仿真方法可有效应用于工程实践。
关键词：皮带轮噪声；结构模态；声腔模态；气动噪声；声压级
Analysis of aerodynamic noise reduction of crankshaft pulley
DING Baoan1,2, ZHANG Xiaohui1,2*, WANG Jingxin1,2, ZHANG Weilong1,2, ZHAO Xuefei1,2, ZHAO Jingjing1,2
1.National Key Laboratory of Internal Combustion Engine and Power System, Weifang 261061, China;
2. Weichai Power Co., Ltd., Weifang 261061, China
Abstract: In order to reduce the noise of the crankshaft pulley, the fluid simulation software STAR ccm+ is used to establish a flow field simulation model, and the acoustic software LMS Virtual lab is used to simulate the aerodynamic noise of the pulley and analyze the structural and acoustic cavity modes of the pulley. The simulation analysis results show that when pulley rotates at high speed, the groove flow velocity between the pulley and the front cover of the gear chamber is uneven, and periodic pressure pulsation is generated on the groove surface, which is the main source of aerodynamic noise of the pulley. A relatively closed cavity is formed inside the groove, and the first-order modal frequency of the acoustic cavity is close to the excitation frequency of the noise source, which increases the noise. The optimized scheme with a 5 mm opening on the pulley is used to compare and verify the aerodynamic noise simulation and testing with the original scheme without a hole on the pulley. The results show that compared with the original scheme, the optimized scheme reduces the root mean square sound pressure level of the aerodynamic noise simulation by about 4 dB, and the root mean square sound pressure level of the acceleration condition test by about 2 dB. The simulation and testing data of the original and optimized schemes are basically consistent, and the simulation method could be effectively used in engineering practice.
Keywords: pulley noise; structure mode; acoustic cavity mode; aerodynamic noise; sound pressure level
