新型导向固定阀塔板流体力学实验研究及数值模拟

发布时间：2019-01-14 06:55

【摘要】：板式塔是最常用的气液传质设备之一,其中,固定阀塔板作为一种整合了筛板塔板和浮阀塔板的优点,并克服了其中的一些缺点的塔板,以其优良的性能而被广泛应用,有很大的研究发展前景。本文以塔板的现有研究为基础,以加强对板上液体的导向性、抑制雾沫夹带为目的,针对当前塔设备对新型塔板开发的需求,开发了一种新型固定阀塔板——低雾沫导向梯形固定阀塔板。因此,本文将从实验和计算流体力学两部分着手,对低雾沫导向梯形固定阀塔板的流体力学性能及塔板上的气液两相流场进行分析研究。实验部分,本文流体力学实验是在1500×400mm的矩形塔中、用空气—水系统在常温常压下完成的。通过调整实验参数(出口堰高、空塔气速与液流强度),测量了本新型塔板的塔板压降、清液层高度、雾沫夹带及漏液这四种流体力学性能参数,探究了这些参数随阀孔动能因子、液流强度及出口堰高的变化规律。同时,通过拟合实验数据,得到了塔板压降、清液层高度、雾沫夹带及漏液的数学关联式,为此塔板进一步的设计与开发提供一定的理论指导。与F1浮阀相比新塔板的干湿板压降分别低30-40%以及10-20%,雾沫夹带低60-70%;与半椭圆固定阀相比新塔板的塔板压降略高,雾沫夹带低40-50%,抑制雾沫夹带的效果明显。模拟部分,本文为了深入分析研究新型导向固定阀塔板上方的气液两相流场分布情况,将建立出塔板模型,借助计算流体力学软件Fluent在气液两相流的条件下进行模拟计算。以双欧拉两相流模型与混合相标准k-ε湍流方程为基础,构造了此导向固定阀塔板的CFD三维模拟模型,模型中采用的动量源项表达式通过实验数据关联得到的平均体积气相含率建立。为了验证所建CFD模型的正确性,本文计算模拟了在与实验参数完全相同的条件下所得到的板上清液层高度,并与实验测量值进行比对。对比结果较吻合,证明所构建的模型能够较好的模拟出新型导向固定阀塔板上的气液两相流场,并根据模拟结果,研究分析了塔板上方的气液两相速度场的分布规律及塔板结构对流场的影响。
[Abstract]:Plate tray is one of the most commonly used gas-liquid mass transfer equipment, in which the fixed valve tray is widely used as a tray which integrates the advantages of sieve tray and floating valve tray, and overcomes some shortcomings. There is a great prospect of research and development. Based on the existing research on tray, this paper aims at strengthening the orientation of liquid on the plate and restraining entrainment of mist and foam, aiming at the demand of the new tray development for the tower equipment at present. A new type of fixed valve tray, low foaming trapezoidal tray, was developed. Therefore, the hydrodynamic properties of trapezoidal fixed valve tray and the gas-liquid two-phase flow field on the trapezoidal valve tray are studied in this paper from the two parts of experimental and computational fluid dynamics. In the experiment part, the hydrodynamic experiment was carried out in 1500 脳 400mm rectangular tower with air-water system at room temperature and atmospheric pressure. By adjusting the experimental parameters (exit Weir height, empty tower gas velocity and liquid flow intensity), the pressure drop of the tray, the height of the liquid layer, the entrainment of mist and the leakage of the liquid were measured. The variation of these parameters with the kinetic energy factor of valve hole, liquid flow intensity and exit Weir height is investigated. At the same time, by fitting the experimental data, the mathematical correlation formulas of tray pressure drop, liquid layer height, entrainment of mist and liquid leakage are obtained, which provides certain theoretical guidance for further design and development of tray. Compared with F1 float valve, the pressure drop of the new tray is 30-40% lower and 10-20% lower than that of the new tray, and the entrainment of mist is 60-70% lower. Compared with the semi-elliptical fixed valve, the pressure drop of the new tray is slightly higher, and the entrainment of foam is 40-50% lower than that of the new tray. In the simulation part, in order to analyze and study the gas-liquid two-phase flow field over the plate of the new type of guide fixed valve, a tray model is established and simulated under the condition of gas-liquid two-phase flow with the help of the computational fluid dynamics software Fluent. Based on the two-Euler two-phase flow model and the standard k- 蔚 turbulent equation of mixed phase, the CFD three-dimensional simulation model of the guide fixed valve tray is constructed. The expression of momentum source term used in the model is established by correlating the experimental data with the average volume vapor holdup. In order to verify the correctness of the established CFD model, the height of the supernatant liquid layer obtained under the same conditions as the experimental parameters is calculated and simulated, and compared with the measured values. The comparison results show that the proposed model can simulate the gas-liquid two-phase flow field on a new type of fixed valve tray, and according to the simulation results, The distribution law of gas-liquid two-phase velocity field over the tray and the influence of the trays structure on the flow field are studied and analyzed.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ053.5

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