The Thermocapillary Effects in Phase Change Materials in Microgravity experiment: Design, preparation and execution of a parabolic flight experiment

Thermocapillary effects during the melting of phase-change materials in microgravity: steady and oscillatory flow regimes

“…This is also behind the term ‘oscillatory mode contribution’ to the phase change and is consistent with the overall enhancement of thermocapillary convection on heat transport that was demonstrated by the works of Ezquerro et al. (2019, 2020) and Salgado Sánchez et al. (2020 b ), and which is apparent in the present results.…”

“…Finally, it is worth clarifying that we have referred to any phase-change transition as 'oscillatory' if it involved oscillatory flows at any lapse during melting. This is also behind the term 'oscillatory mode contribution' to the phase change and is consistent with the overall enhancement of thermocapillary convection on heat transport that was demonstrated by the works of Ezquerro et al (2019Ezquerro et al ( , 2020 and Salgado Sánchez et al (2020b), and which is apparent in the present results.…”

“…Although not directly focused on pattern formation aspects of thermocapillary flows, the recent numerical work of Madruga & Mendoza (2017a,b) is relevant and was the first to suggest the positive effect of thermocapillary convection on heat transport during the melting of PCMs in microgravity. These predictions were recently confirmed by the parabolic flight experiments of Ezquerro et al (2019) and Ezquerro et al (2020), which for the first time observed the melting of n-octadecane in rectangular containers under the presence of a free surface. Salgado Sánchez et al (2020b) then complemented these results by experimentally and numerically examining the effect of the container aspect ratio for Γ = 1-1.66, i.e.…”

“…The phase-change transition is modelled using an enthalpy-porosity based formulation of the Navier-Stokes equations (Voller et al 1987), and analysed for the high-Prandtl-number organic paraffin n-octadecane (Pr = 52.53) due to its relevance to recent microgravity experiments (Ezquerro et al 2019(Ezquerro et al , 2020Salgado Sánchez et al 2020b). The PCM is enclosed in a rectangular (two-dimensional) container with isothermal conditions along the left and right lateral walls.…”

“…The small temperature δ T characterises the interval where solid and liquid phases may coexist, the so-called mushy region (Egolf & Manz 1994). With the selection of n-octadecane for the PCM, as in recent microgravity experiments (Ezquerro et al 2019(Ezquerro et al , 2020Salgado Sánchez et al 2020b), the values of δ T reported in the literature (see e.g. Ho & Gaoe 2009;Velez, Khayet & Ortiz 2015) range from 1 K to 4 K, depending on the experimental technique and the purity of the sample.…”