PIV Measurement for Rayleigh Convection and Its Effect on Mass Transfer

The velocity distribution in Rayleigh convection caused by acetone volatilization in acetone-ethyl acetate binary system was observed in a vertical cross section of an initially quiescent liquid layer by utilizing particle image velocimetry. Obvious turbulent vortexes that were induced by Rayleigh convection appeared in the bulk liquid, and its statistic features indicated that Rayleigh convection became more intense with the increase of Ra number and ReG number. Mass transfer coefficient was measured and the computed enhancement factor indicated that Rayleigh convection could promote the surface renewal of the liquid phase and intensify the interfacial mass transfer significantly. A method was proposed for the prediction of mass transfer coefficient based on the measured velocity vector, and the predicted mass transfer coefficients are in reasonable agreement with the experimental results.

Graphical abstractThe velocity distribution in Rayleigh convection caused by acetone volatilization in acetone-ethyl acetate binary system was observed in a vertical cross section of an initially quiescent liquid layer by utilizing particle image velocimetry. The post-processed velocity distribution via large eddy simulation decomposition was shown in Fig. 1, which displays more detailed turbulent structures of the measured Rayleigh convection. Also, a method for mass transfer coefficient prediction was proposed based on the measured velocity vector, and the predicted mass transfer coefficient was found to be in good agreement with the measured mass transfer coefficient as shown in Fig. 2.Figure optionsDownload full-size imageDownload as PowerPoint slide