Srinivasan S, Saghir M Z
Ryerson University, Toronto, Ontario M5B 2K3, Canada.
J Chem Phys. 2009 Sep 28;131(12):124508. doi: 10.1063/1.3236745.
Experimental investigations on thermodiffusion have been conducted for five different ternary mixtures of methane, n-butane, and n-dodecane at a high temperature and pressure. While the mole fraction of methane was fixed at 0.2 the mole fraction of n-dodecane was varied from 0.7 to 0.2. The experiments were performed in a microgravity environment on board the satellite FOTON-M3. It was found that in all mixtures, n-dodecane separated to the cold side whereas methane segregated to the hot side. n-butane, the species with an intermediate density, showed a change in sign as its mole fraction was increased. At low concentrations it collected on the cold side but moved in the opposite direction with an increase in its mole fraction. The role of the relative density coupled with the species concentrations has been used to explain the thermodiffusion factor in each mixture. Computational investigations showed a similar behavior. However, the theoretical model was not able to capture the sign change of n-butane accurately. The inadequate representation of the significance of the relative densities and the mole fraction of the species has been found as the reason for this.
已针对甲烷、正丁烷和正十二烷的五种不同三元混合物在高温高压下进行了热扩散实验研究。甲烷的摩尔分数固定为0.2，而正十二烷的摩尔分数从0.7变化到0.2。实验在卫星FOTON - M3上的微重力环境中进行。结果发现，在所有混合物中，正十二烷向冷侧分离，而甲烷向热侧偏析。正丁烷，密度处于中间的物质，随着其摩尔分数增加，其偏析方向出现了符号变化。在低浓度时，它聚集在冷侧，但随着摩尔分数增加，它向相反方向移动。相对密度与物质浓度的作用被用来解释每种混合物中的热扩散系数。计算研究显示了类似的行为。然而，理论模型无法准确捕捉正丁烷的符号变化。相对密度和物质摩尔分数的重要性表示不足被发现是造成这种情况的原因。
