Effect of Particle Size on Feedback in an Idealized Annular Flow

The effect of the droplet size and volume fraction on deposition, droplet turbulence and gas turbulence in an idealized gas-liquid annular flow has been examined. Fully-developed disperse flow in a rectangular channel is considered. A direct numerical simulation is used to calculate the gas turbulence seen by the droplets. A point force method is used to calculate the forces exerted by the droplets on the gas turbulence. Inter-droplet collisions are not considered. Gravity is assumed to be zero. Wide range of droplet inertial time constants and of volume fractions are considered. Theories about the momentum transfer in the disperse flow are tested. Correlation between the mean deposition velocity, the particle turbulence and the gas turbulence is shown. The gas turbulence decreases to accommodate the forces exerted by the droplets. Drag reduction is achieved due to the acceleration of the gas by the droplets in the near-wall region.