A classical Euler-Lagrangian model for gas-solid flows was extended with gas component mass conser- vation equations and used to obtain fundamental insights into bubble-to-emulsion phase mass transfer in bubbling gas-...A classical Euler-Lagrangian model for gas-solid flows was extended with gas component mass conser- vation equations and used to obtain fundamental insights into bubble-to-emulsion phase mass transfer in bubbling gas-solid fluidized beds. Simulations of injected single rising bubbles under incipient fiuidiza- tion conditions were carried out, using Geldart-A and -B particles. Phenomena observed in the simulations and those of various theoretical models used to derive phenomenological models were compared to chal- lenge the assumptions underlying the phenomenological models. The bubble-to-emulsion phase mass transfer coefficients calculated for the simulations using Geldart-B particles were in a good agreement with predictions made using the Davidson and Harrison （1963） model. The bubble-to-emulsion phase mass transfer coefficients for Geldart-A particles were, however, much smaller than the predictions obtained from theoretical models （e.g. Chiba and Kobayashi （1970））. The newly developed model allows a detailed analysis of various hydrodynamic aspects and their effects on the mass transfer characteristics in and around rising bubbles in fluidized beds.展开更多
文摘A classical Euler-Lagrangian model for gas-solid flows was extended with gas component mass conser- vation equations and used to obtain fundamental insights into bubble-to-emulsion phase mass transfer in bubbling gas-solid fluidized beds. Simulations of injected single rising bubbles under incipient fiuidiza- tion conditions were carried out, using Geldart-A and -B particles. Phenomena observed in the simulations and those of various theoretical models used to derive phenomenological models were compared to chal- lenge the assumptions underlying the phenomenological models. The bubble-to-emulsion phase mass transfer coefficients calculated for the simulations using Geldart-B particles were in a good agreement with predictions made using the Davidson and Harrison （1963） model. The bubble-to-emulsion phase mass transfer coefficients for Geldart-A particles were, however, much smaller than the predictions obtained from theoretical models （e.g. Chiba and Kobayashi （1970））. The newly developed model allows a detailed analysis of various hydrodynamic aspects and their effects on the mass transfer characteristics in and around rising bubbles in fluidized beds.
