Experimental Study on liquid free Surface in Buoyant-Thermocapillary Convection
- Paper number
IAC-08.A2.4.8
- Author
Prof. Li DUAN, National Microgravity Labrotory, Institute of Mechanick, Chinese Academy of Sciences, China
- Coauthor
Prof. Qi KANG, National Microgravity Labrotory, Institute of Mechanick, Chinese Academy of Sciences, China
- Year
2008
- Abstract
In this paper, surface deformations of buoyant-thermocapillary convection in a rectangular cavity due to gravity and temperature gradient between the two sidewalls has been investigated. The cavity is 52mmx42mm in horizontal cross section, the thickness of liquid layer h is changed from 2.5mm to 6.5mm. In the present paper, surface deformations of h = 3.5mm and 6.0mm have been discussed and compared. Temperature difference is increased gradually, and the flow in liquid layer will change from steady convection to unstable convection. Two kinds of optical diagnostic system with image processor have been developed for study of the kinetics of buoyant-thermocapillary convection?they give out the information of liquid free surface. The quantitative results have been calculated by Fourier transform and correlation analysis respectively. With the increasing of temperature gradient, surface deformations are more and more declining, they have been calculated. Another interesting phenomenon is the inclining direction, which is different between the convections in thin and thick liquid layer. For thin layer, the convection is mainly controlled by thermocapillary effect. However, for thick layer, the convection is mainly controlled by buoyancy effect. The surface deformation analyzed by theories is consistent with our experiment results. The present experiment proved that surface deformation is related with temperature gradient and the thickness of liquid layer. In other words that surface deformation lies on capillary convection and buoyancy convection.
- Abstract document
- Manuscript document
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