气液界面Marangoni效应对传质系数的影响

在气液相际传质过程中，界面Marangoni湍动会对传质过程产生重要的影响，为此，建立了一套气液接触传质设备，以使得通过N2与异丙醇稀溶液逆流接触将液体中使表面张力降低的溶质解吸出来，从而引发Marangoni湍动，提高传质速率。发生Marangoni对流时，液相的传质系数比只依靠扩散传质而不考虑Marangoni效应时大，因此引出增强因子F这一概念，通过计算F的值即可判断Marangoni效应对传质速率影响的程度。提出了一个包括Marangoni准数的计算传质系数关联式，其计算结果与实验结果相符．

Effect of Interficial Marangoni Convection on the Mass Transfer Coefficient

Among the published correlations for predicting the gas-liquid mass transfer coefficient in the falling film process, the Marangoni effect was usually being ignored. Since the Marangoni effect is the main source of inducing interfacial turbulence, by which the mass transfer coefficient can be intensified, the ignorance of such effect will result in inaccurate evaluation of the mass transfer process. In order to study the influence of the interfacial Marangoni effect on the mass transfer, an experiment of desorbing 2-propanol by nitrogen in the falling film process was conducted. It is found that the interfacial Marangoni effect has a significant intensification on the mass transfer coefficient, and it can be expressed by introducing an enhancement factor F. A new correlation of mass transfer coefficient was proposed, in which the dimensionless Sherwood number, ShL, was expressed by a function of the dimensionless group involving Marangoni number Ma and the Reynolds number ReL as following: Sh L = aMab ReLc. Through the regression of our experimental data, the coefficients of the new correlation were determined. The proposed correlation is in good agreement with the experimental data.