Experimental Study And Numerical Simulation Of Rotational Coriolis Force In Small-Scale Solid-Liquid Two-Phase Flow

Coriolis effect is obviously of water movement in large-scale water-area, and in small-scale flow, Coriolis force can be negligible, but there is little research for rotational Coriolis force in small-scale rotational multiphase flow in home and abroad. In this thesis, experiments and numerical simulation are done in vertical and horizontal spiral duct to study motion characteristics and force analysis of spherical single particle. In experiment, works are done by catching particle trajectory using high-speed camera and employing kinetic model of single granular. In numerically simulation, the RNGκ-εmethod and dynamic mesh method loaded UDF file based C language are employed to simulate a single particle trajectory in two-dimensional vertical spiral duct. The major conclusions are as following.(1) In vertical spiral duct, at the same flow, both in rising movement and in decline movement, rotational Coriolis force, centrifugal force and drag force upon single particle increase with pipe radius decrease. In whole movement, centrifugal force upon particle increases with the flow increase or with the pipe radius decrease, and the value of centrifugal force is an important role. The value of rotational Coriolis force sync with drag force, and both value are similar. Effectual gravity upon a particle is important in the whole movement. There is exponential relation between dimensionless quantityλandζ. The samples number of rotational Coriolis force which can be ignored measured measured about one-quarters of the total.(2) In the whole movement of a single particle suspended in vertical spiral duct, effective gravity, rotational Coriolis force and drag force are mainly effect upon the single particle, but in radial component, the main force are rotational Coriolis force and effective gravity, others are small. On some conditions, there is parabolic relation of rotational Coriolis force to centrifugal force. Rotational Coriolis force upon single particle is larger than centrifugal force 2 to 3 orders of magnitude in most conditions.(3) In horizontal spiral duct, centrifugal force, rotational Coriolis force and drag force are mainly effect upon the single particle, but the radial component of drag force is very small. At the same pipe radius, drag force decreases with flow increase, while rotational Coriolis force and centrifugal force increases with flow increase. At the same flow, centrifugal force upon particles decreases with pipe radius increase, while the changes of rotational Coriolis force is complicated, but it increase with pipe radius increasing in most codition. There is exponential relation between dimensionless quantityλandζ. The sample number of rotational Coriolis force which can not be ignored measured about three-quarters of the total.(4) The dynamic mesh method is employed to numerically simulate a single particle trajectory in two-dimensional vertical spiral duct. The results show that:In rising movement, effective gravity and Coriolis force rotation are mainly effect upon the single particle, while centrifugal force and virtual mass force are small. Compared with the measured data, the magnitude of rotational Coriolis force is larger, while centrifugal force and drag force are smaller. In decline movement, effective gravity, centrifugal force and rotational Coriolis force are mainly effect upon the single particle, while virtual mass force is small. Compared with the measured data, the magnitude of centrifugal force and rotational Coriolis force are close to, but drag force is larger than the measured data, especially in the radial component of drag force. The simulation can reflex the movement of particle in the experiment, and the results agree with experiment data of forces.Therefore, both in experiments which were done in vertically or horizontal spiral duct and in numerical simulation, the proportion of rotational Coriolis force upon the single particle is major, that is, the rotational Coriolis force should not be ignored on force analysis of a particle in a small-scale low-velocity rotational two-phase flow.