单缸发动机消声器压力损失的CFD研究

CFD Investigation into Pressure Loss of Single-Cylinder Engine Muffler

测量了某单缸发动机消声器的入口气流脉冲压力信号.依据消声器的实际物理结构,建立了发动机消声器的仿真模型.考虑单缸发动机的排气特性,提出了使用脉冲压力有效值设置边界条件的方法,运用计算流体动力学(CFD)技术仿真计算了消声器内部压力损失的分布情况.根据仿真结果,分析得到消声器内部产生较大压力损失的环节,有针对性地对消声器内部结构进行了改进.在相同工况下,对改进后的消声器入口气流压力信号进行了测量,并再次进行了仿真计算.结果表明,改进后消声器压力损失明显降低,且在内部分布更加均匀.

In this paper, first, the pulse pressure signal at the entrance of a single-cylinder engine muffler was measured. Next, based on the physical structure of the muffler, a simulation model of the muffler was constructed. Then, by considering the exhaust characteristics of the single-cylinder engine, a method was proposed to determine the critical conditions according to the effective pulse pressure. Moreover, the distribution of pressure loss in the muffler was simulated based on the computational fluid dynamics （CFD） , and the simulated results were used to discover the parts with large pressure loss in the muffler, with some measures being taken to improve the internal structure of the muffler. Finally, in the same operation conditions, the entrance pressure signal of the improved muffler was measured and simulated. The results indicate that the pressure loss in the improved muffler falls remarkably and distributes more regularly.