Numerical analysis of n-octadecane melting process in a rectangular cell under reboosting maneuver conditions

Identifier:  imarina:9366511

Handle: https://hdl.handle.net/20.500.11797/imarina9366511

Authors:  Dubert, D; Simon, M J; Massons, J; Ruiz, X; Gavalda, Jna

Abstract:
The improvement of heat management based on Phase Change Materials (PCMs) is of increasing importance in space environments. In this context, a future ESA project called Effect of Marangoni Convection on heat transfer in Phase Change Materials (MarPCM) will evaluate the degree of improvement in heat transport using thermocapillarity as convective activator of the liquid phase generated during the melting. Since this type of project needs to be performed onboard International Space Station, ISS, it is of outmost importance to know if the accelerometric environment of the Station could affect the experiment results.To do so, various 2D simulations of the solid-liquid phase change were carried out using n-octadecane as PCM material, by considering a pre-selected acceleration signal coming from a real ISS reboosting maneuver (June 24, 2021). Different gravity scenarios have been considered by changing both the intensity and the orientation of the reboosting maneuver, parallel (x direction) and perpendicular (y direction) to the thermal gradients. The acceleration levels were enhanced up to 1000 times the intensity achieved during the real reboosting in order to predict the safety margins of the ISS experiment.The results showed alterations of the liquid-solid interface, during the melting process in the high g-level scenarios considered. In these cases, the oscillatory flow pattern became more complex detecting sudden changes in the main frequency which were maintained approximately 1000 s after the reboosting ended. Nevertheless, applying real boosting maneuver no significant influence in the melting process was detected.