液压共振消声器阶跃压力响应及内部流场分析

Analysis of Inner Flow Field and Response of Step Pressure of Hydraulic Helmholtz Resonators

对不同共振腔内径的液压共振消声器内部流场用CFD(computational fluid dynamics)软件进行数值仿真计算,用阶跃压力信号模拟压力冲击,在层流状态下,考虑了流体的可压缩性,利用可视化软件分析共振消声器内部的压力分布和速度分布特性,并根据计算所得阶跃压力响应分析结构对系统性能的影响。结果表明:当共振腔内部的流场在共振腔直径与连接部直径比小于4时,可视为平面波的形式传播;当共振腔直径与连接部直径比大于等于4时,在连接部位附近,压力波是以球面形式扩散的;当共振腔直径过小与过大都会对系统造成不利影响,共振腔直径与连接部直径的合理比值约为4～12。

We simulated the inner flow in hydraulic Helmholtz resonators of different inner diameters of resonant chamber under laminar condition with a CFD （Computational Fluid Dynamics） code. We use step pressure signal to simulate pressure impact with the compressibility of fluid considered. We analyzed the pressure and speed distri- bution inside Helmholtz resonators with visualization application software and the performance of the system affected by resonator structure according to the computed response of step pressure. The result shows that when the ratio of diameter of resonant chamber to that of the neck connecting main pipe and resonant chamber is less than 4, the pressure wave front can be considered as plane, but when the ratio is larger or equal to 4, the pressure wave front around the connection is spherical; and that excessive large or small inner diameter of the resonant chamber might affect the system severely. Therefore, it is reasonable that the ratio of the diameter of the resonant chamber to that of the neck connecting main pipe and resonant chamber should be between 4 and 12.