Marangoni convection and its influence on the mass transter in the liquid phase were investigated. Marangoni convection was visualized using laser Schlieren technique, Orderly polygonal convection patterns and random ...Marangoni convection and its influence on the mass transter in the liquid phase were investigated. Marangoni convection was visualized using laser Schlieren technique, Orderly polygonal convection patterns and random interfacial turbulence were observed. The effect of Marangoni convection on the mass transfer rate was studied by desorbing ethanol from aqneous solution in the falling film. The experimental results show that Marangoni convection can speed up the surface real and enhance the mass transfer rate in the liquid phase.The liquid mass transfer coefficient can be enhanced by as much as 3 folds. The corresponding empirical correlations are given in terms of the mass transfer enhancement factor. Furthermore, in considering the Marangoni effect, the conventional mass transfer correlation was modified, The differences between the values predicted by the correlation and the experimental data are within ±8.2% and the average difference is 4.2%.展开更多
This paper investigated the buoyancy and surface tension-driven ferro-thermal-convection (FTC) in a ferrofluid (FF) layer due to influence of general boundary conditions. The lower surface is rigid with insulating to ...This paper investigated the buoyancy and surface tension-driven ferro-thermal-convection (FTC) in a ferrofluid (FF) layer due to influence of general boundary conditions. The lower surface is rigid with insulating to temperature perturbations, while the upper surface is stress-free and subjected to general thermal boundary condition. The numerically Galerkin technique (GT) and analytically regular perturbation technique (RPT) are applied for solving the problem of eigenvalue. It is analyzed that increasing Biot number, decreases the magnetic and Marangoni number is to postponement the onset. Additionally, magnetization nonlinearity parameter has no effect on FTC in the non-existence of Biot number. The results under the limiting cases are found to be in good agreement with those available in the literature.展开更多
Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied ex...Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied experimentally in a 160×160-mm^2 cavity that ＆ heated from the bottom block. The convection pattern ＆ visualized by an infrared thermography camera. It is shown that the onset of the Benard cell is consistent with theoretical analysis. The wavenumber decreases obviously with increasing temperature, except for a slight increase near the onset. The wavenumber gradually approaches the minimum when the supercritical number e is larger than 10. Finally, a formula is devised to describe the wavenumber selection in supercritical convection.展开更多
基金Supported by National Natural Science Foundation of China(No.20136010).
文摘Marangoni convection and its influence on the mass transter in the liquid phase were investigated. Marangoni convection was visualized using laser Schlieren technique, Orderly polygonal convection patterns and random interfacial turbulence were observed. The effect of Marangoni convection on the mass transfer rate was studied by desorbing ethanol from aqneous solution in the falling film. The experimental results show that Marangoni convection can speed up the surface real and enhance the mass transfer rate in the liquid phase.The liquid mass transfer coefficient can be enhanced by as much as 3 folds. The corresponding empirical correlations are given in terms of the mass transfer enhancement factor. Furthermore, in considering the Marangoni effect, the conventional mass transfer correlation was modified, The differences between the values predicted by the correlation and the experimental data are within ±8.2% and the average difference is 4.2%.
文摘This paper investigated the buoyancy and surface tension-driven ferro-thermal-convection (FTC) in a ferrofluid (FF) layer due to influence of general boundary conditions. The lower surface is rigid with insulating to temperature perturbations, while the upper surface is stress-free and subjected to general thermal boundary condition. The numerically Galerkin technique (GT) and analytically regular perturbation technique (RPT) are applied for solving the problem of eigenvalue. It is analyzed that increasing Biot number, decreases the magnetic and Marangoni number is to postponement the onset. Additionally, magnetization nonlinearity parameter has no effect on FTC in the non-existence of Biot number. The results under the limiting cases are found to be in good agreement with those available in the literature.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11502271 and 11372328the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences under Grant Nos XDA04020405 and XDA04020202-05the China Manned Space Engineering Program
文摘Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied experimentally in a 160×160-mm^2 cavity that ＆ heated from the bottom block. The convection pattern ＆ visualized by an infrared thermography camera. It is shown that the onset of the Benard cell is consistent with theoretical analysis. The wavenumber decreases obviously with increasing temperature, except for a slight increase near the onset. The wavenumber gradually approaches the minimum when the supercritical number e is larger than 10. Finally, a formula is devised to describe the wavenumber selection in supercritical convection.
