Minimum transport boundary for horizontal dense-phase pneumatic conveying of granular materials

A new method of flow blockage collapsing in the horizontal pipe: the pipe-rotation mechanism

In dense pneumatic conveying, flow blockage is a severe problem in the horizontal pipe, so accelerating the collapse velocity of blockage can improve the efficiency of powder transportation. In this paper, we offered a new method of the pipe-rotation mechanism and focused on the effect of this method on blockage collapse from collapse velocity, mass flow rate, and the change of the particle region. The physical model developed is horizontal pipe-rotation geometry at a uniform rotational speed of 0, 150, 300, 450, and 600 rpm, respectively. Then we used a computational fluid dynamics and discrete element method (CFD-DEM) model to investigate a single slug of particles passing through these geometries. The results show that collapse velocity and the mass flow rate increase with increasing rotational speed, which proves that the pipe-rotation mechanism can accelerate the collapse of flow blockage evidently. Moreover, the pipe-rotation mechanism changes the particle region significantly, which is polarized in the lower half of the pipe. It is trusted that the findings reported in this paper well serve as a helping source for further studies toward dense pneumatic conveying.