Analysis Of Hydraulic Transportation In Pipeline Using Sediment Of The Yellow River Downstream

The pipeline transportation technology is widely used in many industrial aspects. The research of two-phase flow in a pipeline has been more and more deeply from domestic and foreign scholars. These reports mainly focused on characteristics of sediment laden flow in pipelines, flow state, distribution of concentration and velocity, critical non-silting velocity and friction head loss. The critical non-silting velocity and friction head loss of muddy water conveyance pipelines are important technical parameters in the design and operation of pipeline system, which are related to selection and operating energy consumption of power equipments. The work is relying on the financial aid of the 12-th five-year Plan National Sci-Tech Support Projects ——“The demonstration in subsidence area of large coal bases using the Yellow River sediment with filling and repairmen technology”.The physical experiments and theoretical analyses of sediment transport through pipeline were carried out with automatic data acquisition system. U-PVC pipelines with three inner diameters 100 mm, 125 mm and 150 mm were applied. The sediment we used was gathered from the canal head of Chengai diversion gate in the Yellow River downstream irrigation area. We analyzed characteristics of sediment laden flow and pipeline transportation technology with the Yellow River sediment- critical non-silting velocity and friction head loss. The main results are as follows.(1) Characteristics of the flow carrying sediment in pipeline were analyzed. The analysis on the formula of critical non-silting velocity and friction head loss needs to be based on vast research works, which are flow characteristics, movement rule of sediment in pipelines and relevant parameters. The flow characteristics in muddy water are different from those in water because of the existence of sediment. In the present study, movement forms of sand grain, the identification on types of muddy water flow and the influence factors of viscidity were assessed to identify hydraulic features of muddy water. Based on these assessments, we determined the formula and discriminated method of related parameters, which provided support for the determining of critical non-silting velocity and friction head loss.(2) The factors that influenced critical non-silting velocity and impact effects were analyzed. The formula of critical non-silting velocity used in this study was determined by means of correlation analysis. The impact effects that factors influenced critical non-silting velocity were summarized with three different pipeline diameters and sand contents. The factors were sand content, pipeline diameter, sediment density and grain composition. Meanwhile, the formula of critical non-silting velocity used in this study was determined in contrast to existing formulas.(3) The factors that influenced friction head loss were summarized according to the multi-group experiments with three different pipeline diameters and sand contents. The factors were summarized to be sand content, flow rate, pipeline diameter and sediment density. According to specific effects of factors, the formula of friction head loss used in this study was determined by means of correlation analysis.