The control of energy in various industrial applications passes by the comprehension of the phenomena of transfers especially in complex flows. The structure of the turbulent flow in the cavities in rotation depends o...The control of energy in various industrial applications passes by the comprehension of the phenomena of transfers especially in complex flows. The structure of the turbulent flow in the cavities in rotation depends on several parameters like the Reynolds number of rotation Ra and the aspect ratio of the cavity. The purpose of this work is to simulate numerically the effect of the aspect ratio on the level of turbulence in the annular steady flow with an incompressible fluid for three different configurations. In the first, the interior cylinder is fixed and the external is moving. The second configuration is the reverse. The third is the contra-rotating cylinders. For all these configurations, we varied the aspect ratio from 0.5 to 2.5. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses （Reynolds Stress Model： RSM）. The results of our numerical simulation show that this geometrical parameter can be an interesting factor to increase the level of turbulence that is often required in several industrial applications where the economy and the control of energy are always required.展开更多
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa...The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.展开更多
文摘The control of energy in various industrial applications passes by the comprehension of the phenomena of transfers especially in complex flows. The structure of the turbulent flow in the cavities in rotation depends on several parameters like the Reynolds number of rotation Ra and the aspect ratio of the cavity. The purpose of this work is to simulate numerically the effect of the aspect ratio on the level of turbulence in the annular steady flow with an incompressible fluid for three different configurations. In the first, the interior cylinder is fixed and the external is moving. The second configuration is the reverse. The third is the contra-rotating cylinders. For all these configurations, we varied the aspect ratio from 0.5 to 2.5. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses （Reynolds Stress Model： RSM）. The results of our numerical simulation show that this geometrical parameter can be an interesting factor to increase the level of turbulence that is often required in several industrial applications where the economy and the control of energy are always required.
文摘The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.
