Study on the flow of water sand slurry with sliding bed in inclined pipe

In order to further study sand particles' transport rules in the inclined slurry pipe associated with the sliding bed, force balance theories are used to study the method for evaluating the suspended layer and sliding bed velocities as well as the sliding bed thickness, and an iterative method for computing the deposit critical velocity is given. Meanwhile, the shear force linear distribution assumption is used and with the aid of prandt empirical formula, a velocity distribution model above the sliding bed is given. Experimental data of coarse sand pipe hydraulic transportation show that the deposit critical velocity is negatively correlated with the particle size and concentration, and it is positively correlated with the pipe dip angle when the transportation concentration is kept constant. The comparison between the calculated results and the measured results show that the maximum deviation of the calculated value from the measured value is 13%. The experimental data also shows that with the increase of the angle of the pipe, the maximum velocity point position has an upward trend. The comparison between the calculated and measured results shows that the deviation of the theoretical velocity distribution model and the measured value is not more than 10%. Results show that the force balance theory and the linear hypothesis of the shear stress distribution apply well in the research of deposition critical velocity and velocity distribution above sliding bed in the inclined coarse sand slurry pipe accompanied with the sliding bed.