INFLUENCE OF G-JITTERS ON THERMODIFFUSION IN A TERNARY MIXTURE: COMPARISON BETWEEN ISS AND FOTON (M12 MISSION) PLATFORMS

摘要

Experiments under microgravity environment have been regarded as an accurate and feasible means for studying the thermal diffusion phenomenon. However the existence of residual gravities (g-jitters), either static or oscillatory, in the space laboratories affects the accuracy of the experiments due to the convection motion that it induces. An appropriate interpretation of the experimental results from the Space relies on a better understanding of the influence of g-jitters on thermal diffusion. In this paper, we modelled the thermal diffusion process with g-jitter data measured onboard the International Space Station (ISS) and FOTON (M12). The system under investigation consists of a rectangular cavity saturated with a ternary mixture of normal butane, dodecane and methane (0.2/0.3/0.5 mole fraction). A lateral heating condition is applied. Comparisons are made between the simulated results for the ISS, FOTON and the ideal zero gravity condition. It is found that the diffusion process is indeed affected by g-jitters in both platforms, however in an insignificant degree. FOTON shows slightly superior to the ISS due to it is low in g-jitter level. The ISS, if very well controlled, is also a good microgravity environment and suitable for performing thermal diffusion studies.