DEM simulation of standpipes under the negative pressure gradient

Abstract A new method based on the force balance was proposed to simulate the flow hydrodynamics of particles in standpipes under the negative pressure gradient. The influence of drag force was integrated into the gravity term and formed a new variable—equivalent gravity (Fe). The acceleration of equivalent gravity (ge) substituted the original acceleration of gravity (g) in a single-phase DEM simulation. In our study, the influence of orifice size and back pressure on particle flow has been studied. The mass flow rate fits well with the experiment results and increases with raising orifice size and decreasing pressure. The voidage distributions and velocity profiles have also been analyzed to investigate the flow behavior. The new method enables the quantitative and qualitative prediction of mass flow rate in a single-phase Discrete Element Method (DEM) simulation.