Study On Flow Law Of Large Particle Slurry In Pipeline

In recent years, more and more slurry pipeline project involves the technology of transporting large particle(particle size more than 0.2 mm) materials. Research on sliding velocity, velocity distribution, hydraulic gradient(friction loss) and concentration distribution is important content in slurry pipeline technology. So far, detail experiment and research are carried out by only a few scholars and experts in these respects. These research fruits can be roughly divided into three types: experimental study results, theoretical study results and synthetical results of experiment and theory. These research fruits fail to clarify the key problems of liquid (water) and solid particles interaction in large particles slurry pipe. In addition, some research results can only be used in certain circumstances, and they lack of wide application value. Therefore, it is necessary to launch the intensive study of large particles slurry flow law in pipeline.Starting with large particles'force balance equation, it is found that there exists extra resistance when large particle flows in pipeline. So the method of using interference force's correction factor to study large particles'motion-resistance force is put forward. And a lot of experts'experimental data are used, through nonliear fitting method, and calculation formula of interference force's correction coefficient is given out. And based on this, sliding velocity between water and solid particle, velocity distribution and the hydraulic gradient(friction loss) are analysed and studied from the standpoint of momentum transmission relationships, and new calculation models of sliding velocity, velocity distribution and the friction loss are put forward. At last, on the basis of large particle motion resistance proposed above, using particle's force balance relationship in the vertical axis direction, concentration distribution calculation model is put forward, and on the basis of relevant study, using theoretical analysis, calculation method of solid particles'diffusion coefficient is given out. Slurry flows with a sliding bed is a special kind of pipeline transportation mode and based on the previous research achievement, calculation model of concentration distribution law above sliding bed is brought forward.The calculating model of sliding velocity, velocity distribution, hydraulic gradients(friction loss) and concentration distribution in this thesis are verified by the related experimental data and the influence of interference force's correction coefficient on sliding velocity, velocity distribution, hydraulic gradients(friction loss) is is analyzed. Furthermore, the error reasons between author's calculated value and measured value are analyzed too.