柴油机排气消声器压力损失的仿真优化论文.pdf

柴油机排气消声器压力损失的仿真优化摘要交通噪声是环境噪声的主要组成部分,如何有效防范和控制交通噪声成为治理噪声危害的重要工作。对于柴油机而言,在排气系统中安装消声器是消减其运转噪声的有效手段,也是目前最经济可行的技术措施。因此, 对柴油机消声器开展研究不仅能提高汽车的驾乘舒适性,而且减小噪声对人类社会生产实践的危害具有重要意义。本文系统阐述了噪声的危害、控制方法和排气噪声产生的机理,并建立了消声器模型对消声器的性能进行了模拟计算,研究消声器结构参数变化对其压力损失和消声量等性能指标的影响。通过将模拟计算与试验分析相结合,为消声器的结构优化设计开辟了新途径。作者首先对消声器的压力损失进行研究。运用Pro/Engineer建立了消声器的三维模型,并将其导入至lJFluent的前置软件Gambit进行网格划分,设定计算的边界条件。然后对模型进行CFD模拟计算,通过消声器的流场分析, 研究了消声器结构对压力损失的影响。计算结果表明,增大消声器第一腔的长度有利于减缓高速气流的扰动,减少涡流强度;扩大出口管直径可防止因出口气流流速过大而引起的再生噪声,同时还能降低排气阻力。根据模拟计算结果评价了消声器设计的几个关键因素,并对消声器的结构设计进行优化,进一步研究结构参数优化对消声器性能的影响。在压力损失研究的基础上,应用比利时LMS公司开发的Sysnoise声学分析软件对消声器的消声性能进行模拟计算。通过对优化前后消声器消声频谱图的对比分析,。结果表明:以流场数值分析为指导可对消声器的压力损失进行优化,而且不会使消声器的消声性能明显变差,通过数值模拟计算分析对消声器进行优化设计是可行的。关键词:消声器压力损失CFD模拟仿真 SIMULATl0N OPTIMIZATl0N ON PRESSUI之E LOSS 0F DIESEL EXHAUSTⅣ几『F’FLER ABSTRACT e themajor part ofenvironmental to effectivelyprevent and controlthetraffic noiseis an important work of control operating noise can beeffectively reduced by applying withmuffler on dieselengine exhaustsystem,which isalsothemost economically technical on muffler ofdieselengine can not onlyimprove fort,but alsoreduce thenoisewhich isharmful toproduction practice of human social. The harmfulness ofnoise,control method ofnoiseandthemechanism of exhaust noise were described model was builtup and simulation ofmuffler’S acoustic performance was of muffler’Sparameters on pressure lossandacousticperformance were research. bination ofsimulation andexperimental opened up anew avenue for structuraloptimization ofthemuffler. The research of the muffler’Spressure loss was obtained firstly. Three—dimensional model ofthemuffler isbuiltby software Pro/Engineer,and imported intoFluent’Spre—software Gambit,and thenmodel was setting theboundary conditions,the numerical simulation ofthemuffler model pleted by Fluentwhich putational fluiddynamics the analysis oftheflowfield,effects ofmuffler’S structure on pr