Microgravity Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario M5B 2K3, Canada.
J Chem Phys. 2013 May 28;138(20):204201. doi: 10.1063/1.4802984.
While the Soret coefficients of binary mixtures have been widely measured in the past, here we report the first measurement of the Soret coefficient of a ternary mixture in a low gravity environment on board the International Space Station. The sample was contained in a 10 mm × 10 mm × 5 mm (w, l, h) cell and was monitored by means of a Mach-Zehnder interferometer at two wavelengths. The analyzed sample was a mixture of tetrahydronaphthalene, isobutylbenzene, and dodecane at the weight fraction of 0.1∕0.8∕0.1. While the lateral walls of the cell did not possess complete thermal isolation, the separation of the components in the central region of the cavity was comparable to purely diffusive behavior. The same experimental parameters have been monitored in Run7 and Run12 of the Selectable Optical Diagnostics Instrument-Diffusion and Soret Coefficient experiment in order to verify the accuracy of the setup. The similarity of the results demonstrates the repeatability of thermodiffusion experiments in a microgravity environment. There was nearly equal separation of the tetrahydronaphthalene and isobutylbenzene components in opposite directions, while dodecane experienced a weak separation in the same direction as isobutylbenzene. Finally, Fourier image processing and calculations of the transient separation of the components were used to analyze the heat transfer in the system and to measure the Soret coefficients for this ternary mixture. The successful measurements shown in this work can serve as the standard for ground experiments and for numerical modeling of hydrocarbon mixtures.
虽然过去已经广泛测量了二元混合物的 Soret 系数，但在这里，我们报告了在国际空间站的低重力环境下首次测量三元混合物的 Soret 系数。样品被包含在一个 10mm×10mm×5mm（w，l，h）的单元中，并通过马赫-曾德尔干涉仪在两个波长处进行监测。分析的样品是四氢萘、异丁基苯和十二烷的混合物，重量分数为 0.1∕0.8∕0.1。虽然单元的侧壁没有完全隔热，但腔室中心区域的组分分离与纯扩散行为相当。为了验证设置的准确性，在 Selectable Optical Diagnostics Instrument-Diffusion 和 Soret Coefficient 实验的 Run7 和 Run12 中监测了相同的实验参数。结果的相似性表明了微重力环境下热扩散实验的可重复性。四氢萘和异丁基苯组分几乎以相反的方向等分离，而十二烷在与异丁基苯相同的方向上经历了微弱的分离。最后，使用傅里叶图像处理和组分瞬态分离的计算来分析系统中的传热，并测量这种三元混合物的 Soret 系数。这项工作中的成功测量可以作为地面实验和烃类混合物数值建模的标准。
