挠性橡胶管管壁对压力波传播速度的影响

为研究挠性橡胶管衰减管内流体脉动的机理,由流体的质量连续和动量方程出发,并将挠性橡胶管管壁 的粘弹性和横截面径向阻抗率加以考虑,得出了管中压力波的波动方程.用波数的概念将管内流动介质的波动方程化为 传递矩阵的形式.。在此基础上,得出了压力波在挠性橡胶管介质中传播时的复波速。为说明管壁的横截面径向阻抗率 对在胶管介质中传播的压力波的影响,与不考虑阻抗率而仅考虑管壁粘弹性的复波速进行了对比,并且分别考虑了厚壁 管和薄壁管两种情况;研究了管中流体流速对其流体脉动衰减的影响并建立了流体脉动衰减的传递损失的公式。计算 结果表明,薄壁管比厚壁管能更有效地抑制脉动;管壁阻抗率对压力波在挠性橡胶管介质中的传播的影响不容忽视;适 当加大挠性橡胶管管径可以更有效地衰减流体脉动。

Acoustic Performance of Flexible Rubber Pipe

In order to study how the flexible rubber pipe suppresses the pulsation of the fluid in it ,the wave equation is derived for the pressure waves inside the flexible rubber pipe by considering the mass continuity equation, the momentum equaiton and the radial impedance of the flexible rubber pipe wall. The resulting wave equation can be readily reduced to a transfer matrix form using an effective wave number for the medium flowing inside the flexible rubber piep. Based on this model ,the complex sound speed in the medium inside the flexible rubber pipe is presented .In order to show the effect of the radial impedance of the flexible rubber pipe wall on the wave propagation in the medium, the complex sound speed is calculated under given conditions. The equivalent wave speed and exponential attenuation factor are compared with that of a pipe taking viscoelasticity into consideration but leaving impedance out of consideration.The thick-wall pipe and the thin-wall pipe are both taken into account. The influence of the velocity of the fluid inside the rubber pipe on suppressing the pulsation of the fluid is also studied, and the transmission loss of the rubber pipe is set up. The results show that considering the radial impedance of the flexible rubber pipe wall or not does affect the evaluation of the equivalent wave speed and the exponential attenuation factor, and their tendency along with the change of frequency is also different. The results imply that the thick-wall pipe is much more likely to be related to the radial impedance of the flexible rubber pipe wall than the thin-wall one. The results also show that the thin-wall pipe is better than the thick-wall one for suppressing the pulsations, and the higher the frequency, the better the pipe suppresses the pulsations A better result of suppressing can be obtained by increasing the diameter of the rubber pipe.