某发动机后处理装置气流再生噪声分析与改进
崔志勇1,2，陈志响1,2，王宁波3，马庆镇1,2，翟旭茂1,2
1.潍柴动力股份有限公司，山东 潍坊 261061；2.内燃机可靠性国家重点实验室，山东 潍坊 261061;
3.潍坊市应急救援服务中心，山东 潍坊 261061
摘要：为降低某发动机后处理装置气流再生噪声，采用计算流体动力学（computational fluid dynamics，CFD）建立后处理装置气流再生噪声有限元模型，进行噪声源强度分析，确定气流噪声最大声压级在出口管后排穿孔处。设计出口管穿孔结构改为插管结构和封堵后排穿孔2种优化方案，进行声压级及传递损失仿真对比；将采用封堵后排穿孔的后处理装置结构与原方案进行车辆加速行驶测试对比。仿真结果表明，2种优化方案的气流噪声声压级均降低，且不影响后处理装置降噪能力。测试试验结果表明，采用封堵后排穿孔的后处理装置结构，噪声明显降低，由流体流动引起的宽频噪声几乎消失，噪声总声压级由原来的90.4 dB下降到82.3 dB。
关键词：发动机；后处理装置；气流再生噪声；传递损失
Analysis of airflow regeneration noise in an engine aftertreatment device and its improvement
CUI Zhiyong1,2, CHEN Zhixiang1,2, WANG Ningbo3, MA Qingzhen1,2, ZHAI Xumao1,2
1.Weichai Power Co., Ltd., Weifang 261061, China;
2.State Key Laboratory of Internal Combustion Engine Reliability, Weifang 261061, China;
3.Weifang Emergency Rescue Service Center, Weifang 261061, China
Abstract：In order to reduce the airflow regeneration noise of an engine aftertreatment device, a finite element model of the airflow regeneration noise of the post-treatment device is established using computational fluid dynamics (CFD). The intensity of the noise source is analyzed, and the maximum sound pressure level of the airflow noise is determined at the perforation in the back row of the outlet pipe. Two optimization schemes are designed: changing the perforation structure of the outlet pipe to an intubation structure and blocking the perforation in the back row, and the sound pressure level and transmission loss are compared by simulation. A comparison is made between the structure of the aftertreatment device that blocks the rear perforation and the original design by vehicle acceleration testing. The simulation results show that both optimization schemes reduce the sound pressure level of airflow noise, and do not affect the noise reduction ability of the post-processing device. The test results also show that using a aftertreatment device structure to seal the rear perforation significantly reduces noise, and the broadband noise caused by fluid flow almost disappears. The total sound pressure level of the noise decreases from 90.4 dB to 82.3 dB.
Keywords: engine; aftertreatment device; air flow regeneration noise; transmission loss
