The undercooling of the single micro-sized droplet of Sn-3.0Ag-0.5Cu(wt%)alloy has been studied via the newly developed fast calorimetric scanning technique,by which the fast heating and cooling treatment for a single...The undercooling of the single micro-sized droplet of Sn-3.0Ag-0.5Cu(wt%)alloy has been studied via the newly developed fast calorimetric scanning technique,by which the fast heating and cooling treatment for a single droplet can be realized,with the maximum heating or cooling rate being 1×104K/s.Owing to the nearly spherical shape of the single droplet upon heating and cooling and the resul-tant geometric stability,the influence of the droplet size on the solidification process could be elimi-nated.As a result,the puzzled issue on how to separate the mutual effects of droplet size and cooling rate in the field of rapid solidification has been primarily solved,making it possible to study separately the effect of droplet size and cooling rate.Meanwhile,the in-situ observation on deep undercooling could be actualized in this condition,differing from that obtained only by theoretical calculation.The results showed that the undercooling was increased with the increasing cooling rate,and the maximum in-situ measured undercooling reached 116.9K.The undercooling of the single droplet,however,was increased abruptly when cooled at the rate of 2×103K/s.The undercooling increased slightly as the cooling rate was increased continuously to 1×104K/s,implying the infeasibility for gaining large undercooling only by increasing the cooling rate.展开更多
The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the...The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence, relative velocity, and axial dispersion when using droplet populance balance models （DPBM）. The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.展开更多
基金Supported by the Robert Bosch Foundation(Grant No.32.5.8003.0025.0/MA01)the National Natural Science Foundation of China(Grant No.50571057)+1 种基金the National High-Tech Research and Development Program of China("863" Project)(Grant No. 2006AA03Z339)the Shanghai Rising-Star Program(Grant No.06QA14020)
文摘The undercooling of the single micro-sized droplet of Sn-3.0Ag-0.5Cu(wt%)alloy has been studied via the newly developed fast calorimetric scanning technique,by which the fast heating and cooling treatment for a single droplet can be realized,with the maximum heating or cooling rate being 1×104K/s.Owing to the nearly spherical shape of the single droplet upon heating and cooling and the resul-tant geometric stability,the influence of the droplet size on the solidification process could be elimi-nated.As a result,the puzzled issue on how to separate the mutual effects of droplet size and cooling rate in the field of rapid solidification has been primarily solved,making it possible to study separately the effect of droplet size and cooling rate.Meanwhile,the in-situ observation on deep undercooling could be actualized in this condition,differing from that obtained only by theoretical calculation.The results showed that the undercooling was increased with the increasing cooling rate,and the maximum in-situ measured undercooling reached 116.9K.The undercooling of the single droplet,however,was increased abruptly when cooled at the rate of 2×103K/s.The undercooling increased slightly as the cooling rate was increased continuously to 1×104K/s,implying the infeasibility for gaining large undercooling only by increasing the cooling rate.
基金Supported by the AiF (Arbeitsgemeinschaft Industrieller Forschungsvereinigungen, "Otto von Guericke" e.V.), the BMWA (Bundesministerium für Wirtschaft und Arbeit) and the DFG (Deutsche Forschungsgemeinschaft)
文摘The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence, relative velocity, and axial dispersion when using droplet populance balance models （DPBM）. The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.
