一种新型结构的分流气体对冲排气消声单元性能分析

发布时间：2019-01-20 16:50

【摘要】：排气噪声是内燃机的主要噪声源,安装排气消声器是降低内燃机排气噪声最直接有效的手段。在消声器的设计中,其两个主要性能指标声学性能和空气动力性能是一对矛.盾,常常不能同时兼顾,因此寻求既消声性能好又排气阻力低的消声器就成为了国内外消声器研究的热点。本文在课题组前期提出的反相对冲排气消声器的基础上,对一种新型结构的排气消声单元利用三维仿真软件对其声学性能和空气动力性能进行了模拟研究。从空气动力性能的角度,利用计算流体力学方法对该分流对冲排气消声单元的压力损失和气流特性进行了数值模拟,并进行了试验验证,证明了此分流对冲排气消声单元原理的正确性。在此基础上利用流体力学方法对其结构进行了优化设计,并对优化了的结构模型进行了压力损失的数值模拟,结果表明,改进后的分流对冲排气消声单元的压力损失得到了极大的改善。对其声学性能,采用声学有限元法,利用声学仿真软件对分流对冲排气消声单元的传递损失进行了模拟分析,结果表明在20Hz-3000Hz频带内此分流对冲排气消声单元具有良好的降噪性能。
[Abstract]:Exhaust noise is the main noise source of internal combustion engine, and installation of exhaust muffler is the most direct and effective means to reduce exhaust noise of internal combustion engine. In the design of muffler, its two main performance indexes, acoustic performance and aerodynamic performance, are a pair of spears. Shield is often unable to take into account at the same time, so it has become a hot spot of muffler research at home and abroad to seek a muffler with good muffler performance and low exhaust resistance. On the basis of the anti-phase anti-exhaust muffler proposed by our research group, the acoustic and aerodynamic performance of a new type of exhaust silencer is simulated by using three-dimensional simulation software. From the point of view of aerodynamic performance, the pressure loss and gas flow characteristics of the unit are numerically simulated by using computational fluid dynamics (CFD) method, and the experimental results are verified. It is proved that the principle of the shunt and counteracting exhaust silencing unit is correct. On this basis, the optimization design of the structure is carried out by using the hydrodynamic method, and the numerical simulation of the pressure loss of the optimized structure model is carried out. The results show that, The pressure loss of the improved shunt and offset exhaust silencing unit has been greatly improved. For its acoustic performance, the acoustic finite element method and acoustic simulation software are used to simulate and analyze the transmission loss of the shunt and hedge exhaust silencing unit. The results show that this diffluence and anti-exhaust noise suppression unit has good noise reduction performance in the 20Hz-3000Hz frequency band.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK403

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