The discrete hard sphere particle model （DPM） is applied in this work to study numerically the distribu- tions of particle and bubble granular temperatures in a bubbling fluidized bed. The dimensions of the bed and ...The discrete hard sphere particle model （DPM） is applied in this work to study numerically the distribu- tions of particle and bubble granular temperatures in a bubbling fluidized bed. The dimensions of the bed and other parameters are set to correspond to those of Miuller et al（2008）. Various drag models and oper- ational parameters are investigated to find their influence on particle and bubble granular temperatures. Various inlet superficial gas velocities are used in this work to obtain their effect on flow characteristics. It is found that the superficial gas velocity has the most important effect on granular temperatures including bubble granular temperature, particle translational granular temperature and particle rotational granular temperature. The drag force model affects more seriously the large scale variables such as the bubble gran- ular temperature. Restitution coefficient influences all granular temperatures to some degree. Simulation results are compared with experimental results by Muller et al. （2008） showing reasonable agreement.展开更多
Under the Eulerian-Eulerian framework of simulating gas-solid two-phase flow, the accuracy of the hydrodynamic prediction is strongly affected by the selection of rheology of the particulate phase, for which a detaile...Under the Eulerian-Eulerian framework of simulating gas-solid two-phase flow, the accuracy of the hydrodynamic prediction is strongly affected by the selection of rheology of the particulate phase, for which a detailed assessment is still absent. Using a jetting fluidized bed as an example, this work investi- gates the influence of solid rheology on the hydrodynamic behavior by employing different particle-phase viscosity models. Both constant particle-phase viscosity model （CVM） with different viscosity values and a simple two-fluid model without particle-phase viscosity （NVM） are incorporated into the classical two- fluid model and compared with the experimental measurements. Qualitative and quantitative results show that the jet penetration depth, jet frequency and averaged bed pressure drop are not a strong func- tion of the particle-phase viscosity. Compared to CVM, the NVM exhibits better predictions on the jet behaviors, which is more suitable for investigating the hydrodynamics of gas-solid fluidized bed with a central jet.展开更多
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51121004)the National Natural Science Foundation of China–China National Petroleum Corporation Joint Fund of Petrochemical Engineering (U1162122) the Program for New Century Excellent Talents in University (NCET-08-0159)
文摘The discrete hard sphere particle model （DPM） is applied in this work to study numerically the distribu- tions of particle and bubble granular temperatures in a bubbling fluidized bed. The dimensions of the bed and other parameters are set to correspond to those of Miuller et al（2008）. Various drag models and oper- ational parameters are investigated to find their influence on particle and bubble granular temperatures. Various inlet superficial gas velocities are used in this work to obtain their effect on flow characteristics. It is found that the superficial gas velocity has the most important effect on granular temperatures including bubble granular temperature, particle translational granular temperature and particle rotational granular temperature. The drag force model affects more seriously the large scale variables such as the bubble gran- ular temperature. Restitution coefficient influences all granular temperatures to some degree. Simulation results are compared with experimental results by Muller et al. （2008） showing reasonable agreement.
基金support from National Natural Science Foundation of China (20976191 and 51025624)Program for New Century Excellent Talents in University (NCET-09-0342)111 Project(B12034)
文摘Under the Eulerian-Eulerian framework of simulating gas-solid two-phase flow, the accuracy of the hydrodynamic prediction is strongly affected by the selection of rheology of the particulate phase, for which a detailed assessment is still absent. Using a jetting fluidized bed as an example, this work investi- gates the influence of solid rheology on the hydrodynamic behavior by employing different particle-phase viscosity models. Both constant particle-phase viscosity model （CVM） with different viscosity values and a simple two-fluid model without particle-phase viscosity （NVM） are incorporated into the classical two- fluid model and compared with the experimental measurements. Qualitative and quantitative results show that the jet penetration depth, jet frequency and averaged bed pressure drop are not a strong func- tion of the particle-phase viscosity. Compared to CVM, the NVM exhibits better predictions on the jet behaviors, which is more suitable for investigating the hydrodynamics of gas-solid fluidized bed with a central jet.
