Semenov Semen N, Schimpf Martin E
Institute of Biochemical Physics RAS, 117977 Moscow, Kosygin Street 4, Russia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Oct;72(4 Pt 1):041202. doi: 10.1103/PhysRevE.72.041202. Epub 2005 Oct 18.
Thermodiffusion (thermophoresis) in liquid mixtures is theoretically examined using a hydrodynamic approach. Thermodiffusion is related to the local temperature-induced pressure gradient in the liquid layer surrounding the selected molecule and to the secondary macroscopic pressure gradient established in the system. The local pressure gradient is produced by excess pressure due to the asymmetry of interactions with surrounding molecules in a nonuniform temperature field. The secondary pressure gradient is considered an independent parameter related to the concentration gradient formed by volume forces, calculated from the generalized equations for mass transfer. Values of Soret coefficients for mixtures of toluene and -hexane are calculated using parameters in the literature. When the molecules are assumed to be similar in shape, the calculated Soret coefficients are lower than the empirical values found in the literature. However, by introducing an asymmetry parameter, which is calculated from independent measurements of component diffusion in the literature, very good agreement is obtained.
采用流体动力学方法对液体混合物中的热扩散（热泳）进行了理论研究。热扩散与所选分子周围液体层中局部温度引起的压力梯度以及系统中建立的二次宏观压力梯度有关。局部压力梯度是由非均匀温度场中与周围分子相互作用的不对称性导致的过剩压力产生的。二次压力梯度被视为与由体积力形成的浓度梯度相关的独立参数，该参数由传质的广义方程计算得出。使用文献中的参数计算了甲苯和正己烷混合物的索雷特系数值。当假设分子形状相似时，计算得到的索雷特系数低于文献中发现的经验值。然而，通过引入一个从文献中独立测量的组分扩散计算得出的不对称参数，得到了非常好的一致性。
