Vertical gas holdup distributions in ambient gassed, hot sparged and boiling systems in stirred tanks using multiple 6 hollow blade disc turbines(CD-6)are reported.The local gas holdup in the boiling system is dramati...Vertical gas holdup distributions in ambient gassed, hot sparged and boiling systems in stirred tanks using multiple 6 hollow blade disc turbines(CD-6)are reported.The local gas holdup in the boiling system is dramatically different from that in the ambient gassed or hot sparged system whether in terms of value or distribution.Under the same total gas flow rate and impeller speed,the local gas holdup is much smaller in the boiling system than that in the ambient gassed or hot sparged system.The hot sparged system has similar vertical gas holdup distributions,with maxima in similar locations but with smaller local gas holdup overall,to those of the ambient gassed system.The designs of existing hot sparged and boiling reactors are based on the ambient gassed system and not optimal.The results are of particular relevance to the design and operation of reactors with hot sparged or boiling liquids.展开更多
The mixing process in a stirred tank of 0.476 m diameter with single, dual and triple 3-narrow blade hydrofoil CBY impellers was numerically simulated by using computational fluid dynamics (CFD) package FLU-ENT6.1. Th...The mixing process in a stirred tank of 0.476 m diameter with single, dual and triple 3-narrow blade hydrofoil CBY impellers was numerically simulated by using computational fluid dynamics (CFD) package FLU-ENT6.1. The multi-reference frame (MRF) and standard k-ε turbulent model were used in the simulation. The shaft power and the mixing time predicted by CFD were in good agreement with the experiment. The effects of tracer feeding and detecting positions on mixing time were investigated. The results are of importance to the optimum design of industrial stirred tank/reactors.展开更多
文摘Vertical gas holdup distributions in ambient gassed, hot sparged and boiling systems in stirred tanks using multiple 6 hollow blade disc turbines(CD-6)are reported.The local gas holdup in the boiling system is dramatically different from that in the ambient gassed or hot sparged system whether in terms of value or distribution.Under the same total gas flow rate and impeller speed,the local gas holdup is much smaller in the boiling system than that in the ambient gassed or hot sparged system.The hot sparged system has similar vertical gas holdup distributions,with maxima in similar locations but with smaller local gas holdup overall,to those of the ambient gassed system.The designs of existing hot sparged and boiling reactors are based on the ambient gassed system and not optimal.The results are of particular relevance to the design and operation of reactors with hot sparged or boiling liquids.
文摘The mixing process in a stirred tank of 0.476 m diameter with single, dual and triple 3-narrow blade hydrofoil CBY impellers was numerically simulated by using computational fluid dynamics (CFD) package FLU-ENT6.1. The multi-reference frame (MRF) and standard k-ε turbulent model were used in the simulation. The shaft power and the mixing time predicted by CFD were in good agreement with the experiment. The effects of tracer feeding and detecting positions on mixing time were investigated. The results are of importance to the optimum design of industrial stirred tank/reactors.
