Numerical investigation of the effects of convective and radiative heat transfers on steady Marangoni convection in a high-Prandtl-number liquid bridge in microgravity
Abstract
Temperature gradient-driven Marangoni convection arises in the liquid involving non-isothermal free surfaces, for instance, in the melt in the floating-zone crystal-growth process. This phenomenon becomes more important in the reduced-gravity environment because the contribution of the body force (e.g., buoyancy) to the flow dynamics becomes weaker and the thermocapillarity can dominate the flow. We focuses our interest on the effects of interfacial heat transfer on the steady Marangoni convection in a high-Prandtl-number liquid bridge. It is well known that the heat transfer through the liquid-gas interface strongly affects the flow structure of Marangoni convection as well as its instability mechanisms. The interfacial heat transfer consists mainly of two component: one is the convection and the other is the radiation. The effect of convective heat transfer has been studied experimentally and numerically by several researchers over the past few decades. On the other hand, that of radiative one has just come to attract attention after recent microgravity experiments on board the International Space Station; therefore, the understanding of the effect of interfacial transfer on Marangoni convection is still not enough. In the present study, we consider a liquid bridge of silicone oil with a Prandtl number of 67 under zero-gravity condition, which is placed inside a cylindrical chamber filled with an argon gas. The flow and temperature fields in the liquid bridge and in the ambient gas are simulated using the commercial CFD software STAR-CCM+ ver. 14.02, and the effects of convective and radiative heat transfers are studied by providing the forced ambient gas flow and by changing the external-wall temperature. It is found that both convection and radiation strongly affects the basic flow and temperature patterns of Marangoni convection in a liquid bridge. The present study should contribute to the currently planned microgravity experiment called JEREMI (Japanese-European Research Experiment on Marangoni Instability).
- Publication:
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43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E2073Y