Oscillatory thermocapillary convection in deformed half zone liquid bridges of low Prandtl number fluids. (October 2021)

• Record Type: Journal Article
• Authors: Le, Chengcheng; Liu, Lijun; Li, Zaoyang
• Is Part Of: International communications in heat and mass transfer. Volume 127(2021)
• Publication Date: 2021-10
• Subjects: Oscillatory thermocapillary convection -- Deformed liquid bridge -- Flow instability -- Low Prandtl number fluid; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Heat -- Transmission; Mass transfer; Periodicals; 621.4022
• DOI: 10.1016/j.icheatmasstransfer.2021.105499
• Languages: English
• ISSNs: 0735-1933

Abstract

Abstract: A series of three-dimensional (3D) transient simulations are carried out to study the onset and features of oscillatory thermocapillary convection in deformed half zone liquid bridges of low Prandtl number fluids ( Pr = 0.01) with unit aspect ratio ( As ). The critical conditions for different volume ratios on ground and under microgravity are determined. It turns out that the threshold of the second bifurcation is more sensitive to volume ratio than the first bifurcation. The thresholds in deformed liquid bridges are usually higher than those in cylindrical liquid bridges. The critical azimuthal wavenumber increases from 2 to 3 with volume ratio. Gravity affects the flow through three factors. Compared with the hydrostatic deformation and heating orientation, buoyancy is marginal to the flow transition. It only affects the threshold and the deviation caused by buoyancy is within 2%. The effects of gravity on the critical conditions are dependent on volume ratio. Except for the threshold, gravity may also affect the critical azimuthal wavenumber and the critical oscillation mode. 3D oscillatory flow regimes with two different oscillation modes are present. A new type of "Rocking" mode is discovered in the present study. Highlights: Oscillatory thermocapillary flow in deformed liquid bridges of Pr = 0.01 are studied. The second bifurcation is more sensitive to volume ratio than the first bifurcation. Effects of gravity on the critical conditions are dependent on volume ratio. A new type of "Rocking" oscillatory flow regime is reported.