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微细粒煤柱浮选过程流体动力学模拟
Alternative TitleHydrodynamic Simulation of Column Flotation for Coal Separation
高明杰
Subtype硕士
Thesis Advisor李春山
2013-04-01
Degree Grantor中国科学院研究生院
Degree Discipline化学工程
Keyword微细粒煤   浮选   数值模拟   计算流体力学   旋流-静态微泡浮选柱
Abstract煤炭分选是低品位煤炭资源提质利用的重要环节,开展微细粒煤柱浮选工艺及设备的研究,是选煤技术发展的一个重要方向。浮选柱流体力学是浮选柱设计放大和优化操作的理论基础,是柱浮选发展的重要研究方向。利用数值模拟方法开展浮选柱流体力学特性的系统研究,能够加深对浮选过程中各相间相互作用规律的理解,为系统揭示浮选柱的放大规律,实现浮选过程强化和浮选柱的优化设计提供有力的理论支持。本论文致力于利用数值模拟技术指导浮选柱设计放大与优化操作,围绕浮选柱局部流体力学特性分布规律开展研究。论文的主要研究内容和结论如下: 1、针对浮选柱体系气含率高、流型复杂的特点,就气液两相湍流模型和相间作用力模型进行分析比较,最后选择Eulerian多相流模型结合Realizable k-ε湍流模型以及修正的Tomiyama曳力系数模型,并考虑升力和虚拟质量力的影响,对传统鼓泡浮选柱内气液两相流进行数值模拟。通过将流体动力学模拟结果与文献报道的实验数据进行对比,验证了所选模型模拟浮选柱体系的可靠性。 2、基于商业CFD软件Fluent,对旋流-静态微泡浮选柱进行气液两相流数值模拟,着重分析了气含率、气液相速度及湍流特性在浮选柱内的分布规律。结论如下: (1) 受旋流作用影响,浮选柱柱体中心气含率较高,气泡有向柱体中心运动的趋势; 随垂直高度增加,旋流作用减弱,气含率分布逐渐趋于均匀。 (2) 气液两相速度(轴向速度、切向速度)分布规律基本相似;切向运动仅存在于旋流分离段,随垂直高度上升,气液相切向运动迅速衰减。 (3) 高湍流区主要分布于旋流分离段,柱浮选段的湍流动能和湍流强度总体较低;原矿矿浆进料引入的不均匀流动增强了柱浮选段的湍动程度,在柱浮选段产生局部高湍流区。 (4) 对矿化管流段的研究表明,管段长度对管段矿化效果影响较大:管段过短,管内湍流得不到充分发展,管内矿化不充分;管段过度延长,管段末端湍流程度减弱,也会影响管段的矿化效果。
Other AbstractCoal preparation is an essential step in upgrading low quality coal resource. And it is a major field of the development of coal preparation technology to study the column flotation technology and flotation column. The fluid dynamics in flotation column is the principle basis of flotation column design and operation optimization. Studying the hydrodynamics systematically by means of numerical simulation can deepen the understanding of reaction between different phases, and provide theory support for flotation process intensification and flotation column design. In this dissertation, the distribution regularities of local hydrodynamic features in flotation column were studied by computational fluid dynamics. The main work and conclusions are as follows: 1. Different turbulence models and inter-phase force models were analyzed and compared with the consideration of high gas holdup and complex flow style in column flotation system. The Eulerian multiphase model in conjunction with Realizable k-ε turbulence model and corrected Tomiyama model for drag force coefficient, including the lift force and virtual mass force, is selected to simulate the gas-liquid two-phase flow in flotation column. The simulation results are consistent with experimental data reported in literature, by which the reliability of the selected models were confirmed in simulating column flotation process. 2. Based on commercial CFD software Fluent, the gas-liquid two-phase flow in cyclonic-static micro-bubble flotation column was simulated. The distribution of gas holdup, phase velocity and turbulence features were analyzed in stress, reaching the following conclusion. (1) The gas holdup is higher in the core district of the column, and the bubbles tend to move centripetally under the effect of rotation flow of the cyclonic section. Then the gas holdup distribution turns event with the height, as the rotation flow fades. (2) The velocities of gas and liquid, both axial and tangential, have similar distribution. In particular, the tangential motion can only be found in the cyclonic separation section. (3) High turbulence was located mainly in the cyclonic separation section, while the introduction of raw mineral slurry caused high turbulence in certain location of the static section. (4) The study focused on pipe section suggests pipe length has a significant influence on the mineralization. Both too short and too long pipes are harmful to the mineralization, depending on different control mechanism.
Pages67
Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/8365
Collection研究所(批量导入)
Recommended Citation
GB/T 7714
高明杰. 微细粒煤柱浮选过程流体动力学模拟[D]. 中国科学院研究生院,2013.
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