This paper investigates the effect of non-uniform temperature gradient and magnetic field on Marangoni convection in a horizontal fluid layer heated from below and cooled from above with a constant heat flux. A linear...This paper investigates the effect of non-uniform temperature gradient and magnetic field on Marangoni convection in a horizontal fluid layer heated from below and cooled from above with a constant heat flux. A linear stability analysis is performed. The influence of various parameters on the convection onset is analyzed. Six non-uniform basic temperature profiles are considered, and some general conclusions about their desta- bilizing effects are presented.展开更多
This study is devoted to investigate the effect of induced magnetic field on fully developed magnetohydrodynamic(MHD)natural convection flow of electrically conducting fluid in a vertical annular micro-channel formed ...This study is devoted to investigate the effect of induced magnetic field on fully developed magnetohydrodynamic(MHD)natural convection flow of electrically conducting fluid in a vertical annular micro-channel formed by two concentric cylinders in the presence of imposed radial magnetic field.The velocity slip and temperature jump at the annular micro-channel surfaces are taken into account.The influence of induced magnetic field arising due to the motion of an electrically conducting fluid is taken into consideration.The governing equations of the motion are a set of simultaneous ordinary differential equations and their exact solutions in dimensionless form have been obtained under relevant boundary conditions.The expressions for velocity field,the induced magnetic field,temperature field,induced current density and skin friction have been obtained.A parametric study of the physical parameters is conducted and a representative set of numerical results for the velocity field,the induced magnetic field,temperature,induced current density,volume flow rate and skin friction are illustrated graphically to show interesting features of the radius ratio,rarefaction,fluid wall interaction,Hartmann number and the magnetic Prandtl number.During the course of investigation,it is found that for fixed value of Hartmann number,the skin friction profiles in the presence of induced magnetic field are higher compared to the case when the induced magnetic field is neglected.展开更多
The effect of a transverse magnetic field on the oscillatory thermocapillary con- vection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magne...The effect of a transverse magnetic field on the oscillatory thermocapillary con- vection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magnetic field was applied, as shown by the decrease in the amplitude and the frequency. Furthermore, the os- cillation under smaller temperature difference was stabilized after the magnetic field was applied. The magnetic effect could be due to the Lorentz force generated by the interaction between motional ions and the vertical magnetic field. The ionic conductivities were measured to demonstrate the effect of the magnetic field. The solid ionic electrical conductivity increases with the temperature rise, and the melt ionic electrical conductivity was measured to be about 2.0×10-4 -1cm-1. Experi- mental results manifest that the effect of the magnetic field on anions and cations in the melt makes the flow change to the direction normal to the applied field, so the flow is more orderly and the oscillation is suppressed.展开更多
The axial and radial convective flow,temperature fluctuation and distribution in the HMCZ silicon melt are studied tentatively.The experimental results show that the axial and radial convective speeds,the tempera- tur...The axial and radial convective flow,temperature fluctuation and distribution in the HMCZ silicon melt are studied tentatively.The experimental results show that the axial and radial convective speeds,the tempera- ture variation and the radial temperature gradient,parallel to magnetic field and near melt surface,all decrease,but the axisymmetry of temperature distribution no longer exists when the magnetic field is applied.展开更多
基金supported by the Science Fund Research Grant from Kementerian Sains dan Teknologi(MOSTI)
文摘This paper investigates the effect of non-uniform temperature gradient and magnetic field on Marangoni convection in a horizontal fluid layer heated from below and cooled from above with a constant heat flux. A linear stability analysis is performed. The influence of various parameters on the convection onset is analyzed. Six non-uniform basic temperature profiles are considered, and some general conclusions about their desta- bilizing effects are presented.
文摘This study is devoted to investigate the effect of induced magnetic field on fully developed magnetohydrodynamic(MHD)natural convection flow of electrically conducting fluid in a vertical annular micro-channel formed by two concentric cylinders in the presence of imposed radial magnetic field.The velocity slip and temperature jump at the annular micro-channel surfaces are taken into account.The influence of induced magnetic field arising due to the motion of an electrically conducting fluid is taken into consideration.The governing equations of the motion are a set of simultaneous ordinary differential equations and their exact solutions in dimensionless form have been obtained under relevant boundary conditions.The expressions for velocity field,the induced magnetic field,temperature field,induced current density and skin friction have been obtained.A parametric study of the physical parameters is conducted and a representative set of numerical results for the velocity field,the induced magnetic field,temperature,induced current density,volume flow rate and skin friction are illustrated graphically to show interesting features of the radius ratio,rarefaction,fluid wall interaction,Hartmann number and the magnetic Prandtl number.During the course of investigation,it is found that for fixed value of Hartmann number,the skin friction profiles in the presence of induced magnetic field are higher compared to the case when the induced magnetic field is neglected.
基金the National Natural Science Foundation of China (Grant No. 50331040)the Innovation Funds from Shanghai Institute of Ceramics,Chinese Academy of Sciences (Grant No. SCX0623)
文摘The effect of a transverse magnetic field on the oscillatory thermocapillary con- vection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magnetic field was applied, as shown by the decrease in the amplitude and the frequency. Furthermore, the os- cillation under smaller temperature difference was stabilized after the magnetic field was applied. The magnetic effect could be due to the Lorentz force generated by the interaction between motional ions and the vertical magnetic field. The ionic conductivities were measured to demonstrate the effect of the magnetic field. The solid ionic electrical conductivity increases with the temperature rise, and the melt ionic electrical conductivity was measured to be about 2.0×10-4 -1cm-1. Experi- mental results manifest that the effect of the magnetic field on anions and cations in the melt makes the flow change to the direction normal to the applied field, so the flow is more orderly and the oscillation is suppressed.
文摘The axial and radial convective flow,temperature fluctuation and distribution in the HMCZ silicon melt are studied tentatively.The experimental results show that the axial and radial convective speeds,the tempera- ture variation and the radial temperature gradient,parallel to magnetic field and near melt surface,all decrease,but the axisymmetry of temperature distribution no longer exists when the magnetic field is applied.
