Soluble gas absorption and dispersion inside side-by-side water micro-cylinders containing solid core

Abstract

The gaseous sulfur dioxide intrusion into and dispersion inside the binary heterogeneous water micro-cylinders with side-by-side configuration are presented. The vortexes outside/inside micro-cylinders as well as the solute transport problem are numerically studied at varied Reynolds number (30 ≤ Re ≤ 160) and solid fraction (0.2 ≤ S ≤ 0.8) at a fixed gap-ratio (G/R = 1.0) in the gaseous air stream. The steady symmetric, deflected and flip-flopping flow were clearly observed with increasing Reynolds numbers. The solid core inside water micro-cylinders and the regulated non-uniform interfacial momentum exchange creates main stream driven primary and shear reversed secondary vortexes. Theses eddies constructed inflow/outflow vortex pairs dominate solute transfer, where the soluble gas was quickly entrained into the micro-cylinders by virtue of inflow-type vortex pairs at the separation point and was blocked due to outflow type vortex pairs at the stern regions. The lowest sulfur dioxide concentration is always located at the back of solid nucleus. The transient sulfur dioxide absorption and saturation of micro-cylinders pair were affected by the Reynolds number and the solid fraction. Moreover, diffusion gradually dominate mass transfer processes with increasing solid fraction. The insight into the effects of vortex and solid fraction on advective-diffusion will better understand the physics of gas-liquid flow interaction and solute transport inside water micro-cylinders.