Thermocapillary-driven dynamics of a free surface in microgravity: Response to steady and oscillatory thermal excitation

Abstract

A numerical analysis of the thermocapillary-driven dynamics of a free surface in microgravity is presented for an open container of liquid subjected to steady or oscillatory thermal excitation. The response to this forcing is analyzed for parameters representative of common silicone oils. In contrast to previous investigations, we permit large-scale unconstrained motion of the contact points and deformation of the free surface, which allows us to study the interaction between free surface dynamics and thermocapillary flow. First, the response of the free surface to steady thermal excitation is considered and characterized by the asymmetry of the contact points. Linear dependence of this asymmetry on the applied Marangoni number is found, which is amplified by the vibroequilibria effect when supplemental (high-frequency) vibrations are introduced. In low-viscosity liquids, the transient dynamics of the free surface includes sloshing modes, suggesting that thermal modulation may be used to excite them. The free surface response to oscillatory thermal excitation is then studied for a wide range of parameters, including variations in contact angle β, viscosity ν, container length L, and fluid height H. We perform a frequency analysis and obtain Bode-type diagrams for the contact point oscillations, characterizing the low-frequency response by its amplitude and phase with respect to the thermal forcing, and demonstrate a resonance peak corresponding to the principal sloshing mode. Overall, these results indicate the potential of oscillatory thermal excitation for fluid control in microgravity.

Metastable Liquid Properties and Surface Flow Patterns of Ultrahigh Temperature Alloys Explored in Outer Space

“…[9][10][11][12][13][14][15] Especially, some novel properties and flow behaviors for a liquid in outer space has aroused great research interests in the fields of materials and chemistry. [16][17][18][19][20][21][22] Not only the liquid state is a fundamental problem in physical chemistry, surface chemistry and high temperature chemistry, [23][24][25][26][27] but also the research of liquid properties and the chemical bonds in outer space will play a significant role in multidisciplinary research connecting chemistry with space physics and metallic materials. [28][29][30][31] The metastable liquid thermophysical properties and surface flow patterns of refractory alloys with liquidus temperatures (T L ) beyond 2000 K face the challenges of high-temperature chemistry reactivity, intense volatilization, and droplet deformation.…”

Metastable Liquid Properties and Surface Flow Patterns of Ultrahigh Temperature Alloys Explored in Outer Space

“…[9][10][11][12][13][14][15] Especially, some novel properties and flow behaviors for a liquid in outer space has aroused great research interests in the fields of materials and chemistry. [16][17][18][19][20][21][22] Not only the liquid state is a fundamental problem in physical chemistry, surface chemistry and high temperature chemistry, [23][24][25][26][27] but also the research of liquid properties and the chemical bonds in outer space will play a significant role in multidisciplinary research connecting chemistry with space physics and metallic materials. [28][29][30][31] The metastable liquid thermophysical properties and surface flow patterns of refractory alloys with liquidus temperatures (T L ) beyond 2000 K face the challenges of high-temperature chemistry reactivity, intense volatilization, and droplet deformation.…”

“…However, there are still many mysteries for liquids at extraordinary environments, like superhigh or ultralow temperatures, and hyporgravity or microgravity [9–15] . Especially, some novel properties and flow behaviors for a liquid in outer space has aroused great research interests in the fields of materials and chemistry [16–22] . Not only the liquid state is a fundamental problem in physical chemistry, surface chemistry and high temperature chemistry, [23–27] but also the research of liquid properties and the chemical bonds in outer space will play a significant role in multidisciplinary research connecting chemistry with space physics and metallic materials [28–31] …”

Three-Dimensional Effects During Thermocapillary-Driven Melting of Pcms in Cuboidal Containers in Microgravity

“…The efficacy of thermocapillary convection and complementary strategies like nanoparticles for improving PCM performance in microgravity environments will be directly evaluated by the "Effect of Marangoni Convection on Heat Transfer in Phase Change Materials" (MarPCM) project, which is planned for implementation by the European Space Agency (ESA) on the International Space Station (ISS) [38,39]. A range of numerical investigations have recently been conducted in support of this anticipated experiment and the questions it addresses, including an analysis of dynamical modes and their effect on heat transport [18][19][20]31], melting with combined gravitational and thermocapillary convection [40,41], PCM melting in a liquid bridge configuration in microgravity [27,28,37,42,43], the influence of surface heat exchange [30,44,37], the effect of nanoparticles [45], and the coupling between thermocapillary flows and sloshing [46][47][48][49][50].…”