Study on Pressure Fluctuation of Coarse Slurry Flow in Pipes

(1)目的：通过对水平管内固液两相流动压力波动特性的研究，特别是粗颗粒浓度、颗粒直径和细颗粒添加剂浓度对入口和充分发展区压力波动的影响，管道内颗粒行为与压力波动的关系，以及MEP在管内固液两相流动压力波动中的应用研究，为粗泥浆管道系统的设计提供一些有意义的成果。(2)为达到这一目的，水平管内粗颗粒流动压力波动的测量，测量了流动中固液两相的速度及其脉动分布，并对细颗粒添加剂对压力脉动的影响进行了实验研究。结果：a)充分发展区压力脉动随固体浓度和颗粒直径小于2 mm的增大而增大。当超过2 mm时，压力波动不受颗粒直径的影响，几乎呈现恒定值。b)离固体喂料器的距离影响压力波动。然而，当管道中形成沙丘时，沿管道的波动水平几乎相同。c)由于流动特性影响压力波动，在有沉积床的流动和有移动床的流动的过渡区观察到由于固体运动引起的最大压力波动。d)观察到细颗粒添加剂可以减小压力波动。e)应用MEP估计管道内固液流动压力波动的概率密度函数。

(1)OBJECTIVE: This research objective is to get some siginificant fruits for designing coarse slurry pipeline system from the study on the characteristics of pressure fluctuations in solid-liquid flow in horizontal pipes, especially, on the effects of coarse solid concentration, particle diameter and fine particle additive concentration on the pressure fluctuations in entrance and fully developed region, the relation between the particle behavior in pipes and the pressure fluctuations and on application of MEP to the pressure fluctuations in solid-liquid flow in pipes.(2)APPROCH: In order to achieve the objective, the measurement of pressure fluctuations in coarse slurry flow in horizontal pipes, the measurement of velocity and its fluctuation profile of solid and liquid in the flow and an experimental study on the effect of fine particle additive on the pressure fluctuations are projected.RESULTS: a) The pressure fluctuation in fully developed region increases with an increase in the solid concentration and particle diameter under 2 mm. Once it exceeds 2 mm, the pressure fluctuation is not affected by the particle diameter and nearly shows the constant values.b) The distance from the solid feeder affects the pressure fluctuation. However, when dunes are formed in the pipes, the fluctuation level is ovserved to be almost the same along, the pipes.c) The maximum pressure fluctuations due to the solid motion are observed in the transition region from the flow with a deposit bed and the one with a moving bed since the flow behavior effects the pressure fluctuations.d) The fine particle additive is observed to reduce the pressure fluctuation.e) It became clear from the application of MEP to estimattion of the probability density function of pressure fluctuation in solid-liquid flow in pipes that four moments MEP distribution function is suitable for the probability density function.