Water model experiments were carried out to investigate the bubble behavior in cylindrical and square vessels under centric mechanical stirring.The bubble behavior in the square vessel was investigated in detail by us...Water model experiments were carried out to investigate the bubble behavior in cylindrical and square vessels under centric mechanical stirring.The bubble behavior in the square vessel was investigated in detail by using a high-speed camera to record the transient images of the bubbles.An image analysis software was used to obtain the bubble diameter.The results showed that the centric mechanical stirring in the square vessel was suitable for breakage and dispersion of bubbles,but not suitable for that in the cylindrical vessel.Increasing the impeller blade length and impeller rotation speed was beneficial to disintegrate and disperse bubbles widely.The bubble diameter decreased with the increase in the Weber number and increased slightly with the increase in the modified Froude number.The dimensionless correlation equation of bubble diameter was obtained by the dimensional analysis method.展开更多
The gas–liquid flow behavior of the stirred flow field,the different positions of a single bubble,the initial velocity,the surface tension and the agglomeration of multiple bubbles were studied by CFD numerical simul...The gas–liquid flow behavior of the stirred flow field,the different positions of a single bubble,the initial velocity,the surface tension and the agglomeration of multiple bubbles were studied by CFD numerical simulation.The results show that the pressure distribution and velocity distribution inside the fluid during agitation indicate that the velocity difference between the liquid and the gas phase and the collision between the bubbles caused by the turbulent behavior of the liquid are the important conditions leading to the bubble breakage.Different initial bubble positions and initial bubble velocities have important effects on single bubble breakage.The surface tension is an important condition that affects the bubble breakage.When the surface tension coefficient is 0.7,the bubble will be stretched to the smallest degree;when the surface tension coefficient is 0.1,the bubble will be stretched to the largest degree and it will be easily broken into smaller bubbles.The multi-bubble results show the states and trajectories of coalescence between bubbles.The research results can provide data support for the engineering application of desulfurization process and theoretical guidance for the research of bubble breaking mechanism.展开更多
基金This work was supported by the Key Technologies Research and Development Program(Nos.2017YFC0210404 and 2017YFC0210403-04)the National Natural Science Foundation of China(Nos.U1760120,U1710257,U1702253,and U1903129).
文摘Water model experiments were carried out to investigate the bubble behavior in cylindrical and square vessels under centric mechanical stirring.The bubble behavior in the square vessel was investigated in detail by using a high-speed camera to record the transient images of the bubbles.An image analysis software was used to obtain the bubble diameter.The results showed that the centric mechanical stirring in the square vessel was suitable for breakage and dispersion of bubbles,but not suitable for that in the cylindrical vessel.Increasing the impeller blade length and impeller rotation speed was beneficial to disintegrate and disperse bubbles widely.The bubble diameter decreased with the increase in the Weber number and increased slightly with the increase in the modified Froude number.The dimensionless correlation equation of bubble diameter was obtained by the dimensional analysis method.
基金supported by the National Natural Science Foundation of China(51904069)the Fundamental Research Funds for the Central Universities(N2223026)the Scientific Research Fund Project of Northeastern University at Qinhuangdao(XNY201808).
文摘The gas–liquid flow behavior of the stirred flow field,the different positions of a single bubble,the initial velocity,the surface tension and the agglomeration of multiple bubbles were studied by CFD numerical simulation.The results show that the pressure distribution and velocity distribution inside the fluid during agitation indicate that the velocity difference between the liquid and the gas phase and the collision between the bubbles caused by the turbulent behavior of the liquid are the important conditions leading to the bubble breakage.Different initial bubble positions and initial bubble velocities have important effects on single bubble breakage.The surface tension is an important condition that affects the bubble breakage.When the surface tension coefficient is 0.7,the bubble will be stretched to the smallest degree;when the surface tension coefficient is 0.1,the bubble will be stretched to the largest degree and it will be easily broken into smaller bubbles.The multi-bubble results show the states and trajectories of coalescence between bubbles.The research results can provide data support for the engineering application of desulfurization process and theoretical guidance for the research of bubble breaking mechanism.
