Effect of blade tilt angle on fluid flow characteristics in spray-blowing agitation composite process:a simulation

Aiming at the paddle tilt angle of the spray-blowing agitation composite process,the four-blade stirring and blowing composite desulfurization agitator was chosen as the research object,and the computational fluid dynamics numerical simulation was used to investigate the changes in flow field velocity,turbulent kinetic energy magnitude,and distribution caused by the blade tilt angle.Furthermore,the impact of blade tilt angle on the flow fragmentation behavior of individual bubbles and the coalescence process of multiple bubbles at different positions was studied.Under the same stirring and blowing process parameters,with the increase in the blade tilt angle of the agitator,the velocity of the flow field and the average turbulent kinetic energy inside the agitator decreased,and the bubble fragmentation speed decreased while the merging speed accelerated.The turbulent kinetic energy at the agitator bottom was greater when the blade tilt angle was 3.2°compared to when it was 13.2°,while the turbulent kinetic energy at the agitator upper part was relatively smaller.The results for single bubbles represented the state and trajectory of the bubble fragmentation process,and the results for multiple bubbles illustrated the state and trajectory of the bubble aggregation process.

Simulation of bubble breaking process in a jet mixing reactor for desulfurization of molten iron

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.