大型波纹规整填料塔二维返混特性实验测量与模拟

Experimental Measurement and Simulation of Two Dimensional Dispersion in Commercial Scale Column Containing Corrugated Structure Packing

以热水为示踪剂,对填充有塑料制250Y板波纹规整填料的直径1m的填料塔进行了二维返混特性研究.实验填料塔装填高度2,000mm,装填10层填料,每层200mm,层与层之间交错90°摆放.实验中示踪剂为连续注入,采用铂电阻温度探头分别测量了填料塔距塔顶400mm和1000mm 2个平面的无因次温度分布.应用柱坐标二维返混模型得到了轴向和径向返混系数Dz和Dr,结果发现因为规整填料的各向异性,由模型计算得到的温度场在距离塔顶较远的1000mm平面与实验符合较好,而在较近的400mm平面与实验相差较大.在此基础上提出了基于直角坐标系的各向异性返混模型,每层填料逐层计算,层之间按实际情况旋转90°,结果表明使用相同的Dz和Dr为参数,得到的温度场在400mm平面和1000mm平面均与实验符合良好.

The two-dimensional dispersion in a commercial scale column containing plastic 250Y Mellapak corrugated structure packing was studied by using hot water as tracer.The experimental column was 1000mm in diameter with a 2000mm height of packing.The packed bed consisted of 10 structured packing layers(packages),each 200mm in thickness,which were placed alternatively with 90°rotation.The water temperatures were measured by a number of platinum resistance thermometers installed in two cross sections of the column,apart from the top inlet by 400,and 1000mm respectively.By applying the axial symmetrical dispersion model in cylindrical coordinate,the axial and radial dispersion coefficients Dz and Dr were obtained.It was found that the simulated temperature field agreed well with the experimental data in the 1000mm section,but not in the 400mm section.This is due to the fact that the flow in Mellapak packing is anisotropic,and displays isotropic character only after several alternatively installed layers of structured packing.In order to overcome such difficulty,an integrated layers model was established in Cartesian coordinate,by which the calculation was performed layer by layer with 90°rotation to account for the anisotropic effect.The simulated temperature field by such integrated layers model with Dz and Dras known parameters agrees satisfactorily with the experimental data in both 400mm and 1000mm sections.