An indirect expansion technique was proposed to measure the gas holdup in a non-transparent bubble column with 0.1 m inner diameter and height of 5.2 m.Air and distilled water were employed as gas and liquid phases,respectively.The experimental results show that the average and maximum errors of gas holdup are less than 2% and 4.5%,respectively,between the indirect expansion and pressure drop methods at atmospheric or elevated pressure.Moreover,the gas holdup increases with operating pressure when the superficial gas velocity is a constant,while the effect of static liquid height on gas holdup can be ignored when the operating pressure and superficial gas velocity are fixed.
Bubble behavior was observed by using high-speed digital camera in a two-dimensional rectangular bubble column of 0.20 m(width)× 0.02 m(thickness)× 2.00 m(height).Air and water were used as gas and liquid phases,respectively.Hydrodynamic simulation was conducted in the platform of commercial software package,ANSYS CFX 10.0,by combining the classical two-fluid model of turbulence and GRACE drag model.The computational distributions of bubble size from the MUSIG(multiple size group)model considering bubbles breakup and coalescence were in good agreement with experimental data,which showed that this model could be used to predict the bubble size distribution in the gas-liquid bubble column.
