微加工色谱柱内的传质过程研究.docVIP

 微加工色谱柱内的传质过程研究# 李龙1，闫孝红2，杨剑1，王秋旺1** （1. 西安交通大学 能源与动力工程学院 热流科学与工程教育部重点实验室，西安 710049； 5 10 15 20 25 30 35 2. 西安交通大学化学工程系，西安 710049） 摘要：色谱分离性能的高低取决于其填充介质的结构，传统的填充色谱柱已经不能满足日益 提高的分离要求，而微加工柱列是色谱柱中的一种新形式，可以获得更加良好的分离性能。 在这种柱列中的弥散作用主要受柱列排列方式的影响。为了获得较小的弥散系数以提高分离 性能，本文采用 COMSOL 软件求解基于体积平均法的模型方程，比较顺列、错列结构下的 纵向弥散系数大小。其中柱体高度与直径之比为 2，通道为无限大，孔隙率固定为 40%。在 本文研究的条件下，结果表明，纵向弥散系数随着 Pe 数的变化而变化，在低 Pe 数时其为一 常数，超过一定的 Pe 数时剧烈增加；错列中的纵向弥散系数小于顺列中的纵向弥散系数； 对称结构的纵向弥散系数远远小于不对称结构。 关键词：工程热物理；色谱；弥散；柱列阵列；体积平均 中图分类号：TQ021.4 MASS TRANSFER IN MICROFABRICATED PILLAR ARRAY COLUMNS LI Long1, YAN Xiaohong2, YANG Jian1, WANG Qiuwang1 (1. Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xian Jiaotong University, Xian 710049; 2. Department of Chemical Engineering, Xian Jiaotong University, Xian 710049) Abstract: The performance of chromatographic separation depends on the structure of packing medium. The traditional packing chromatographic columns can’t meet rising requirements about separation. Microfabricated pillar array column is one new type of chromatographic columns. It can improve the performance of chromatographic separation. Dispersion in this type column is influenced by the packing pattern of pillars. In this study, the longitudinal dispersion coefficients of the in-line and staggered arrangements were investigated by using software COMSOL. The volume-average method was applied. The height-diameter ratio was 2. The array channel was considered to be infinite and its porosity was fixed at 0.4. Under the conditions of this paper, the computational results show that, the longitudinal dispersion coefficient is affected by the Peclet number. For relatively small Peclet number, the longitudinal dispersion coefficient is constant. When the Peclet number is larger than certain value, the longitudinal dispersion coefficient starts to increase rapidly. The longitudinal dispersion coefficient of the staggered arrangement column is smal