【作者】 郭锴；

【导师】 郑冲； 冯元鼎；

【作者基本信息】 北京化工大学 ， 化学工程， 1996， 博士

【摘要】 超重机，是近年来兴起的一种利用离心力模拟超重力，强化气液两相传质与反应的新型化工机械。本研究的目的是研究液体在超重机转子内的流动情况，为今后进一步的传质与应用研究提供液体在转子内流动的理论与实验依据。此项研究包含两个实验和转子内液体流动的数学模拟以及液相传质系数与液体流动的关系等几部分内容。 实验之一是转子填料内液体流动的观测与填料表面液膜厚度的测定。在这个实验中，利用安装在转子上，与转子一同旋转的电视摄象机，观察到了离心加速度在200个g(g为重力加速度)以内的液体在填料内的流动情况。发现，除填料内缘处几毫米的区域外，液体在大部分填料当中是以液膜方式流动为主，其周向速度与转子大致相同。基于观测到的图象资料，利用图象分析的方法，测量了在填料表面的液膜厚度。结果显示，在泡沫金属填料上，液膜厚度大约在30-80微米范围。这一数值，明显高于空隙率和比表面都与它接近的不锈钢丝网填料上10微米左右的液膜厚度。分析原因认为这一差异与填料的结构和表面粗糙度有关。 在填料内缘几毫米以内，液体的流动状态比较复杂。自液体喷口喷出的液体与高速旋转的转子填料剧烈撞击，破碎、变形、产生大量的新鲜表面。观察到存在着两个方向的流动。一个是自喷口喷出的液体的径向运动，另一个是液体的径向运动受到填料的阻挡，改变运动方向造成的周向运动。这两个方向的运动，造成了在这几毫米内液体的高度混合。 实验之二是液体在填料内停留时间分布的测量。分别安装在填料内外缘处，与填料一同旋转的两个电导探头，同时给出了注入电导率与水不同的示踪物时电导率随时间的变化曲线。经计算机数据采集和处理，得到在不同实验条件下液体在转子内的停留时间分布。定量分析的结果表明，液体的平均停留时间随液体的流量、转子转速的上升而下降，其大致范围在几百毫秒左右，并且不受气体加入的影响。但是，当转子的转速超过800-1000rpm后，平均停留时间下降的趋势变得平缓。为考察填料内缘附近液体的混合程度，将入口电导探头沿半径方向向填料内部移动10毫米。此时平均停留时间与全程数据没有明显差别，而方差却仅为全程值的1／3。即在内缘处7％的填料造成的混合，是全部填料混合程度的70％。更多还原

【Abstract】 Higee, which exerts centrifugal force as high-gravitec force to intensify mass transfer and chemical reaction between gas and liquid phases, is a new type of machine in chemical industry. The purpose of this dissertation is to study how liquid flows inside the higee rotor. For the purpose, two experiments are employed. Based on results of experiments, a mathematical model is built. The dissertation also includes a study of mass transfer coeffecients and applications of conclusions.The first experiment is to study liquid flowing inside the rotor by visual investigation, and try to measure the thickness of liquid film on the surface of the packing. With a video camera, which is fixed on the rotor and naturally, goes with the rotor synchronously, one can see liquid flowing inside the rotor packing .The video image gives direct evidence of flow patterns. By this method, we know that when the centrifugal acceleration is less than 200 times of gravity, in most of packing, most of liquid flows in films except in the zone closed to the inner edge for a few millimeters. Furthermore, its peripheral speed is almost as same as the rotor’s. Having seen phenomena, we use image analytic method to measure film thickness on packing surface. On the foam metal packing, it is about 30-80 microns. These numbers are clearly higher than that on wire mesh packing, it is about 10 microns. The difference may be related to the structure and the roughness of packing surface.Close to the inner edge of the packing, the liquid flowing is rather complex. The liquid which comes from nozzles dashes against rotating packing violently, then breaking, reforming, making huge amounts of fresh surfaces. In this section, two flowing directions are observed. One is the radial flow that comes from the nozzle; the other is peripheral flow that comes from resisted radial flow having changed its flowing direction. The two flow directions make extremely high mixing in just a few millimeters.The second experiment is to measure the liquid residence time distribution in the packing. There are two conductivity sensors fixed on the rotor. When the tracer is injected into the packing, the two sensors give out relationships between conductivity and time. Aided by a computer, the residence time distributions are gotten under a series operating conditions. The results show that the rough range of mean residence time is about several hundred milliseconds, and it does not change with the countercurrent gas flow rate. The results also更多还原