具有柔性衬里的压力脉动衰减器滤波特性

为了改善传统扩张室压力脉动衰减器脉动衰减性能，提出了一种敷设聚氨酯衬里的改进型脉动衰减器. 根据衰减器分布参数与集中参数特性，研究该改进型结构滤波特性. 首先通过一维解析法构建传统扩张室分布参数模型，获得的理论插入损失与实验测量结果吻合良好，证明了该方法用于脉动衰减器建模的可行性；之后利用该一维解析法构建改进型脉动衰减器直通穿孔管段分布参数模型，敷设聚氨酯衬里的阻性部分则构建集中参数模型，最后研究了衬里材料成分、穿孔率以及穿孔直径对衰减器滤波特性的影响. 研究结果表明:在500 Hz频带范围内，液体静压力稳定在2.76、4.14、4.83 MPa时，老化聚氨酯衬里能显著改善脉动衰减器的插入损失；无论聚氨酯材料老化处理与否，不同液体静压力均对插入损失产生影响；穿孔率和穿孔直径对其插入损失影响较小. 

Filtering Characteristics of Hydraulic Suppressor with Compressible Liner

An improved expansion chamber hydraulic noise suppressor with a compressible polyurethane liner was introduced to improve the pulsation attenuation performance of conventional suppressors. The filtering characteristics of this improved configuration were studied based on the characteristics of distributed and lumped parameters. First, a distributed parameter model of a conventional expansion chamber was developed using a one-dimensional (1D) analytical approach. Theoretical insertion loss (IL) is in good agreement with the experimental results. This illustrates that the method is also applicable to hydraulic suppressors. Then, a distributed parameter model of the perforated tubes in this improved structure was developed by utilizing the 1D method. A lumped parameter model works well for modelling the behaviour of the compliant lining part. Finally, the effects of voiding, porosity, and hole diameters on the performance of the improved expansion chamber hydraulic suppressor were studied. The results show that within frequencies of 500 Hz, voided urethane lining can remarkably improve IL at 2.76, 4.14 MPa, and 4.83 MPa. IL is affected by different hydrostatic pressures, regardless of whether the liner is voided or not. The effect of porosity and hole diameters on IL is marginal.