【作者】 姜正良；

【导师】 宗润宽；

【作者基本信息】 天津大学 ， 化工过程机械， 2005， 硕士

【摘要】 直筒型导叶直流式三相旋流器是WX/4U脱硫装置的一个核心部件,其主要对来自文丘里洗涤器的气体与捕捉了粉尘且吸收了二氧化硫的液滴进行有效的分离。深入了解其内部气液流场结构特性,有助于WX/4U脱硫装置脱硫效率的提高和操作性能优化。本文主要采用实验测量和使用FLUENT软件数值模拟的方法对三相旋流器内部流场结构进行研究,并将实验测得的数据和数值模拟的结果进行对比,对比结果表明采用数值模拟的方法可较好地进行气相流场分析。同时发现,由于三相旋流器气相流场各向异性的特性,RSM湍流模型最适合该设备内部流场的研究。并采用RSM模型对三相旋流器的速度场和压力场进行全面的研究,在筒体中心处发现了不利于分离的回流。选用RSM湍流模型进一步对导流叶片、导流棒和排气管结构对流场特性的影响进行了数值分析,发现延长导流叶片在导流棒上的弧长和减少导流叶片在筒体内壁的弧长能适当减少靠近导流棒处气体的轴向速度;当导流棒长度增加到2100mm时,筒体中心处的回流现象也得到明显改善;通过数值模拟的方法可为已选定的风机选择合适的排气管结构,现有排气管结构对现选用的风机是合适的;这些结构方面研究为三相旋流器在工业上的应用提供了可靠的理论依据。在使用RSM湍流模型对三相旋流器气相流场研究的基础上,采用拉格朗日离散相模型对气液分离效率进行了初步的探讨。模拟结果表明,数值模拟可以较好得描述颗粒在三相旋流器内的运动轨迹。数值模拟和理论推导的初步探讨为难以测定的液滴分离效率的研究打下了基础。更多还原

【Abstract】 Cylindrical three-phase cyclone with a vaned inlet and a direct-current outlet is akey part of WX/4U flue gas desulfurization system. Its main function is to separatethe gas and scrubbing liquid droplets collected dust particles and absorbed sulfurdioxide from venturi scrubber. Knowing its internal flow field structure deeply is helpfor improving the separation efficiency of flue gas desulfurization system andoptimizing the operation performance. In this paper, the internal flow field ofthree-phase cyclone is investigated experimentally and numerically. In addition theexperimental data are compared with that of numerical simulation. And the resultsshow that the numerical method can simulate the gas flow field well and RSM modelis fit for the simulation of the flow field in the three-phase cyclone for its anisotropicproperty. Furthermore the distribution of velocity field and pressure field in thethree-phase cyclone are investigated using RSM turbulent model. The simulationresults found that there is an inversed flow that is unfavorable to separation in thecenter of three-phase cyclone.The influence of the structure of guide vane, cylindrical baffle and discharged pipeon the flow field characteristics of three-phase cyclone has been analyzed using RSMturbulent model. The simulation result shows that prolonging guide vane in thecylinder baffle and reducing guide vane at inwall of cylinder could reduce axialvelocity of gas near the cylinder baffle. If the cylinder baffle length is up to 2100mm,the inversed flow will be weakened. On the other hand, the numerical method canchoose suitable discharged pipe for selected fan. Present discharged pipe is suitablefor present fan. The research about three-phase cyclone’s structure provides reliabletheoretical basis for its industrial use.Based on the research of gas phase flow field using RSM model, Lagrange discretephase model is introduced for preliminary research of separation efficiency on gasand droplet. And the result indicates the particle movement in the three-phase cyclonecan be described through numerical simulation. The way that combines theoreticaldeduction and numerical simulation has some instructional sense to separationefficiency that is hard to measured.更多还原