Gas-particle flow of pneumatic conveying in vertical pipes simulated using four-way coupled second-order moment method

Gas-particle flow in vertical pipes and its anisotropic behavior of turbulence were investigated using the novel four-way coupled second-order moment method of the fluid-particle Eulerian–Eulerian two-fluid model. In this study, the flow behavior of a gas-particle two-phase flow in a vertical pipe was simulated. The study investigated the gas turbulence affected by the presence of particles. For instance, the enhancement of the gas turbulence due to the presence of particles having a diameter of 500 µm, causing wake shedding and the dissipation of particle fluctuation was predicted by the effect of the fluid-particle and particle-particle interactions. Furthermore, the anisotropic turbulence of the gas phase was also predicted to be enhanced by the presence of 500-µm particles, wherein the anisotropic ratio of the second-order moment of the gas phase turbulent velocity was predicted to be in the range of 2–12. Contrarily, in the presence of smaller particles with a diameter of 200 µm, the anisotropic turbulence of the gas phase was predicted to be attenuated, and the anisotropic ratio was reduced to the range of 1–2. In addition, the absolute value of the turbulence dissipation of particles due to fluid-particle interactions was predicted to be half of that due to particle collisions. The anisotropic behavior of these turbulence dissipations was predicted close to the anisotropic behavior of particle turbulence in both the distribution and value.