粗颗粒在复杂空间形态管道水力输送中运动形式的研究

采用高速摄像技术,探讨了不同粒径、体积浓度和输送速度条件下,粗颗粒在复杂空间形态管道中的运动状态及临界条件。研究结果表明:粗颗粒在复杂形态管道中的运动状态表现出不同的特点,水平管道中以滑动推移为主要运动形式,倾斜上升管道中以滑动推移和悬移为主要运动形式,倾斜下降则主要存在下滑和悬移两种;粗颗粒在管道中的运动状态与颗粒粒径、管道形态等因素有关,就悬移运动状态而言,倾斜角度越大,粗颗粒越容易形成悬移。基于试验结果提出了临界条件的计算公式,实测值与计算值基本吻合。

Study on the Movement State of Coarse-grain during Hydraulic Transportation in Pipeline of Complex Spatial Morphology

The movement and critical condition of coarse grains with different particle sizes,volume concentrations and transportation speeds in the pipeline with complex spatial morphology were examined by using high-speed camera technology.Results suggested that the movement of coarse grains in the pipeline with complex spatial morphology had the following characteristics: For the coarse grains in horizontal pipe,a sliding motion becomes dominant.Coarse grains are mainly suspended or sliding in an upward-inclined pipe,while being suspended or falling in a downward-inclined pipe.Thus it was concluded that the movement of coarse grains in pipeline is closely related to factors,including grain size,pipe form,and the suspension of coarse grains is apt to occur in a pipeline with big dip angle.A formula was also obtained for the critical conditions based on the test result,with which the theoretical calculation showed a relatively good agreement with practical measurements.