Laser Schlieren device was established to observe Rayleigh-Bénard-Marangoni effect produced in thick liquid depth by the diffusion of binary liquid mixtures.A recorder and a camera separately recorded dynamic and...Laser Schlieren device was established to observe Rayleigh-Bénard-Marangoni effect produced in thick liquid depth by the diffusion of binary liquid mixtures.A recorder and a camera separately recorded dynamic and static convective flow patterns during experiment.According to different signs of Ma number and Ra number,different binary liquid mixtures were selected to investigate the RBM effect induced by different driven mechanism including density gradient or surface tension gradient or combination of both.Qualitative analysis to experiment results was presented.展开更多
By utilizing optical Schlieren method, the Rayleigh Bénard Marangoni convection in mass transfer process was observed. A recorder and a camera separately recorded dynamic and static convective flow patterns dur...By utilizing optical Schlieren method, the Rayleigh Bénard Marangoni convection in mass transfer process was observed. A recorder and a camera separately recorded dynamic and static convective flow patterns during experiments . Different organic solvents were selected to investigate the RBM effects induced by different driving mechanisms including density gradient, surface tension gradient and their combination. Thermal effects produced by solvents evaporation and solute absorption/desorption are thought as an important factor in the creation of RBM convection during the mass transfer process. Qualitative analysis of experimental results is presented on the basis of photos and videotapes that were taken as direct visual evidences. Experimental results show that the thermal effect accompanying the mass transfer can be a cause at the onset of RBM convection and can′t be neglected simply in study of RBM effect driven by mass transfer.展开更多
Rayleigh-Marangoni-Bénard instability in a system of two-layer fluids is studied nu- merically.The convective instabilities in the system of Silicon Oil(10cSt)and Fluorinert(FC70)liquids have been analyzed.The cr...Rayleigh-Marangoni-Bénard instability in a system of two-layer fluids is studied nu- merically.The convective instabilities in the system of Silicon Oil(10cSt)and Fluorinert(FC70)liquids have been analyzed.The critical parameters at onset of convection are presented in a large range of two-layer depth ratios from 0.2 to 5.0.Numerical results show that the instability of the two-layer system depends strongly on its depth ratio.When the depth ratio increases,the instability mode changes from mechanical coupling to thermal coupling.Between these two typical coupling modes, a time-dependent oscillation is detected.Nevertheless,traveling wave states are found in the case of oscillatory instability.The oscillation mode results from the competition between Rayleigh instability and Marangoni effect.展开更多
The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are ob...The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed.展开更多
文摘Laser Schlieren device was established to observe Rayleigh-Bénard-Marangoni effect produced in thick liquid depth by the diffusion of binary liquid mixtures.A recorder and a camera separately recorded dynamic and static convective flow patterns during experiment.According to different signs of Ma number and Ra number,different binary liquid mixtures were selected to investigate the RBM effect induced by different driven mechanism including density gradient or surface tension gradient or combination of both.Qualitative analysis to experiment results was presented.
文摘By utilizing optical Schlieren method, the Rayleigh Bénard Marangoni convection in mass transfer process was observed. A recorder and a camera separately recorded dynamic and static convective flow patterns during experiments . Different organic solvents were selected to investigate the RBM effects induced by different driving mechanisms including density gradient, surface tension gradient and their combination. Thermal effects produced by solvents evaporation and solute absorption/desorption are thought as an important factor in the creation of RBM convection during the mass transfer process. Qualitative analysis of experimental results is presented on the basis of photos and videotapes that were taken as direct visual evidences. Experimental results show that the thermal effect accompanying the mass transfer can be a cause at the onset of RBM convection and can′t be neglected simply in study of RBM effect driven by mass transfer.
基金The project supported by the National Natural Science Foundation of China (10372105) and the Knowledge Innovation Program of Chinese Academy of Sciences (KJCX2-SW-L05)
文摘Rayleigh-Marangoni-Bénard instability in a system of two-layer fluids is studied nu- merically.The convective instabilities in the system of Silicon Oil(10cSt)and Fluorinert(FC70)liquids have been analyzed.The critical parameters at onset of convection are presented in a large range of two-layer depth ratios from 0.2 to 5.0.Numerical results show that the instability of the two-layer system depends strongly on its depth ratio.When the depth ratio increases,the instability mode changes from mechanical coupling to thermal coupling.Between these two typical coupling modes, a time-dependent oscillation is detected.Nevertheless,traveling wave states are found in the case of oscillatory instability.The oscillation mode results from the competition between Rayleigh instability and Marangoni effect.
文摘The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed.
