摘要
旋转气固两相流动的研究是多相流研究的重要分支。它广泛地应用于能源动力、环境保护、石油化工、制冷低温及航天技术等领域。本文的研究对象是使用了旋流技术的旋涡流化床,该炉型在中小型流化床锅炉上有独特的优势,具有良好的发展前景。
本文在对流化床气固多相流模型全面总结的基础上,基于颗粒动力学理论,使用欧拉-欧拉双流体模型,运用Fluent软件对由切向射入二次风形成旋转气流的旋涡流化床内单相及两相流动进行了三维数值模拟,通过改变流化床一、二次风配比,二次风入射角度,二次风喷嘴直径等条件研究床内流场变化,比较得出有利于延长颗粒在炉内停留时间的宏观条件,对旋涡流化床的设计提供一定的参考。另外,本文在相同工况下分别应用RNGk -ε模型和雷诺应力模型进行模拟,对模拟结果进行了分析对比。
而后在切向射入二次风的基础上加入一次风旋转射流,比较这两种旋流产生方式。比较同向射入和反向射入二次风对床内流场的影响。找到有利于延长颗粒在炉内停留时间,减少扬析损失的射流方式。
本文的研究,较系统地阐明了旋涡流化床内的流动规律,有助于推进提高旋涡流化床效率的深入研究,充实和丰富了旋涡流化床多相流的研究成果。
Eddy gas and solid two-phase flow is the important embranchment of multiphase flow. It applied in energy power, environment protect, oil chemical, low temperature and spaceflight technique widely. Eddy two phases flow is applied in engineering, study of fluid boiler which had eddy technology, this technique had special advantage in small-sized and middle-sized boilers, and it has good foreground.
This literary grace fluidized bed gas and solid two phases flow model was summered up comprehensive. Based on particles dynamics theory, Euler-Euler two-phase model was used, simulated one-phase and two-phase flow in the vortexing fluidized bed combustor when secondary wind ripped into from shear direction using Fluent software, according to change the proportion of one wind and second wind, the angle of secondary wind, the muzzle diameter of secondary wind to research the change of dynamics field in boiler, the macro-scopical conditions which were good for particles staying in boiler were got, it provided some reference for the vortexing fluidized bed combustor design. In addition, k ?ε/RNG model and Renault model were used to simulated eddy gas and solid two-phase flow, and the result were analysed and compared.
One-wind eddy jet based on second-wind jet along shear direction, compare two kind eddy mode. The effect for dynamics field of fluidized bed boiler was compared when one-wind and second-wind were the same direction and the opposition direction. The jet model was well for particle staying and reduce losing was found. Last, new improvement print method was brought forward based on the object which had been summed up and concluded.
According to the research, the flow law of the vortexing fluidized bed combustor was expatiated, it is good for improving eddy fluidized bed boiler efficiency, enriched the research about eddy fluidized bed boiler.
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