Experimental and Numerical Investigation on Interfacial Mass Transfer Mechanism for Rayleigh Convection in Hele-Shaw Cell
Zhen Zhang, Qiang Fu, Huishu Zhang, Xigang Yuan, Kuotsung Yu
Abstract
To understand better the evolution of convective finger for Rayleigh convection confined in a gap with moderate width, we investigated the absorption of CO2 into water experimentally and numerically. A combined particle image velocimetry (PIV) and laser-induced fluorescence (LIF) method was used to measure simultaneously the instantaneous liquid velocity and solute concentration distributions in a Hele-Shaw cell. The process was then simulated using a 3D model with nonequilibrium interfacial boundary condition. An investigation in the gap direction showed that the intrinsic mechanism of interfacial mass transfer enhancement relies on a concentration boundary thickness decrease both inside and outside of convective fingers. On the basis of the simulation results, we present a vortex model for characterizing the interfacial mass transfer coefficient in the constant convective period. The model performs well using the penetration model by relating the gas–liquid contact time to the inverse of average vorticity value in liquid within 4 mm near the interface.