单缸发动机消声器压力损失的CFD研究

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.

CFD Investigation into Pressure Loss of Single-Cylinder Engine Muffler

Abstract Certain single-cylinder engine muffler’s entrance pulse pressure signal was measured. Basing on the muffler’s physical model, muffler’s analytical model was built. Considering the especial character of single-cylinder engine’s tail gas, a calm airflow was selected to replace the tail gas of single-cylinder engine, then the analytical model was used to compute the pressure loss distributing in the muffler. Basing on the result of computation, these parts which produce biggish pressure loss in the muffler were discovered. Aiming at these parts，the muffler was improved. At the same working state of the engine, the entrance pressure signal of the improved muffler was measured, and it’s analytical model was computed again. The result indicates that the pressure loss is reduced markedly in the improved muffler and distributes more regularly.