The volume ratio effect on flow patterns and transition processes of thermocapillary convection

Abstract

Thermocapillary convection has always been one of the most important research topics in microgravity fluid physics. A space experimental study on the thermocapillary convection in an open annular liquid pool – a typical thermocapillary flow system – has been conducted on the SJ-10 satellite of China. This space experiment has observed the spatial temperature distribution of the liquid free surface using an infrared thermal imager, obtained the flow pattern transition process, analysed the oscillation characteristics and revealed the instability mechanism of themocapillary convection. The shape effects on the flow instability are researched by changing the volume ratio, Vr, which denotes the ratio of the liquid volume to the volume of the cylindrical gap between the walls. The volume ratio effect has been focused on for the first time. For a certain volume ratio, the flow pattern would transform from the steady state to the oscillation state accompanied by directional propagating hydrothermal waves with increasing temperature difference. In addition, the significant influences of the volume ratio on the critical conditions and wavenumber selection have been analysed in detail.

Solution Printing of Electronics and Sensors: Applicability and Application in Space

“…High temperature can cause thermal evaporation during the transfer of solutions, which will make the solution completely dry before its deposition; however, the thermal evaporation effect will increase the efficiency of the liquid solidification and annealing process. Thermal convection is another phenomenon caused by high temperature, [ 79 ] which can promote the mixing of solutions during printing, but the convection can easily harm the quality of the printed films and is always hard to control. For low temperatures, it is not good for the whole printing process because of the potential liquid freezing.…”

Academician Wen-Rui Hu — Eminent Pioneer and Prominent Leader of Microgravity Science in China

“…In addition to the liquid bridge configuration, the highly dependency of the critical parameter, the volume ratio, is also applicable to the configurations of rectangle liquid pool (Li et al 2012 ) and annular liquid pool (Kang et al 2019a , b , d ).…”

“…Moreover, the bifurcation route is sensitive to the changes in the aspect ratio of the limited liquid layer. The process of destabilization and transition routes of thermocapillary convection in an annular (cylindrical) liquid pool was studied experimentally by Kang et al ( 2019a , b , d ) aboard China recoverable satellite SJ-10. The system is established by heating the inner copper wall and cooling the outer copper wall of the annular liquid pool.…”

Transient Marangoni convection induced by an isothermal sidewall of a rectangular liquid pool

“…2020), an annular liquid pool (Kang et al. 2019) and droplet systems (Zhang, Duan & Kang 2016; Masoudi & Kuhlmann 2017; Hu, Yan & Chen 2019) has been widely investigated using scaling analysis, asymptotic theory, numerical simulation and experiments both on the Earth and in space. Recently, Marangoni convection on a sinusoidal substrate (Yoo, Nam & Ahn 2019) and a slip substrate (Kowal et al.…”