共查询到17条相似文献,搜索用时 906 毫秒
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旋风分离器是循环流化床锅炉的关键部件之一,其分离性能将直接影响整个循环流化床锅炉的总体设计及锅炉的运行性能.大型循环流化床锅炉采用多个旋风分离器与炉膛出口并联布置实现气固分离.研究其分离系统的气固两相流动特性可进行旋风分离器的分离性能分析。本文针对600 MW超临界循环流化床锅炉的冷态模型,采用电容层析成像测量技术进行旋风分离器入口烟道内气田两相流固相颗粒浓度测量,在不同床料量和炉膛表观风速下,研究多个旋风分离器入口固体颗粒分布特性,得到不同分离器入口处固体颗粒浓度随流化风速、初始物料量的变化,分析了电容原始信号的波动特性,研究结果对流化床大型化多分离器优化布置提供了支持. 相似文献
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多旋风分离器及返料系统是保证循环流化床锅炉高效燃烧的关键设备,是循环流化床大型化研究的关键部件之一。本文采用电容层析成像技术结合压力测量,对多旋风分离器返料系统内部气固两相流场进行实验研究。通过六旋风分离器冷态循环流化床电容层析成像浓度分布和压力测量,揭示循环流化床多分离返料系统颗粒流动分配特性,为循环流化床锅炉大型化,特别是超临界锅炉多旋风分离器的优化布置提供科学依据,基础实验数据库和技术手段,研究内容将电容层析成像技术的应用扩展到工程设计中,对实际工程起到理论指导的作用。 相似文献
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出口几何结构对循环流化床锅炉性能影响的试验研究 总被引:9,自引:0,他引:9
1前言 循环流化床燃烧技术作为高效清洁燃煤技术,由于其能燃用各种劣质燃料而得到迅速发展,并在锅炉上得以广泛应用. 相似文献
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富氧燃烧(Oxy-fuel combustion)技术作为燃烧中CO2捕集技术,在技术适用性和经济性上具有较强的优势。循环流化床富氧燃烧技术(Oxy-CFBC)兼顾富氧燃烧和循环流化床燃烧的优点,燃料适应性广,烟气中CO2富集程度高,易于低成本实现CO2的捕集。本文梳理了近十五年国内外学者对Oxy-CFBC技术的研究成果,从Oxy-CFBC装置、流化特性、燃烧特性、污染物生成与控制、燃料、富氧燃烧电站系统优化、新一代循环流化床富氧燃烧技术以及国内外专利情况等方面进行了总结和分析,最后对Oxy-CFBC在中国未来发展趋势进行展望。 相似文献
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提出了不同密相区结构形状(球形、椭球形、方形体)的固态医疗垃圾循环流化床(SMW-CFB),并针对SMW-CFB各段特征,对循环流化床不同密相区形状对固态医疗垃圾颗粒运动特性的影响进行了数值研究,结果表明:密相区为球形体结构比其它结构形状密相区更易出现回流.密相区不同形状时,颗粒运动进入分离器的时间不一样.固态医疗垃圾颗粒在循环流化床内,直径在大于3.5 mm的垃圾颗粒,随烟气上升到一定高度后,落回密相区,而直径小于3.5 mm的颗粒随烟气一同进入分离器,分离器可以捕集直径大于0.025 mm的颗粒,直径小于0.025 mm的颗粒由排气管排出.球形和椭球形密相区有助于垃圾颗粒与风充分混合接触,有利于垃圾颗粒的燃烧. 相似文献
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工业生产中通常采用多分离器布置的方案增大循环流化床的容量.本文采用大涡模拟-离散单元法(Large eddy simulation-Discrete element method,LES-DEM)对六分离器循环流化床内气固流动特性进行了全循环数值模拟研究。该方法在欧拉框架下求解流体的运动,在拉格朗日框架下追踪每个颗粒的运动。结果表明:六个旋风分离器回路中存在着气固分配不均现象,旋风分离器的轴对称布置方式优于中心对称布置方式.提升管内呈现强烈的颗粒聚团行为,颗粒团的体积大致为正态分布频率,其纵横比都大于1,并且随着提升管高度先增加后减小. 相似文献
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Y. Koide 《Zeitschrift fur Physik C Particles and Fields》1989,45(1):39-41
By starting from a mass matrix with family-independent mixing (the so-called “democratic” family mixing) and by requiring some simple constraints on the additional mass terms, but without any small parameters, a mass relation which is in excellent agreement with experiment is derived for charged leptons. 相似文献
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Liquidus equations for solid-liquid equilibria in quaternary systems involving compound semiconductors are presented in both thermodynamic (model-independent) and regular solution forms. A unified treatment is offered for terminal (doubly-doped binary compound, singly-doped ternary solution) as well as continuous series of solid solutions (mixing on one or both sublattices) which is facilitated by the choice of binary compounds as components in the solid. With the exception of the quaternary solid solution with mixing on both sublattices (i.e. AluGa1?uPvAs1?v), the liquidus equations are generalizations of previous results for ternary systems. In the case of mixing on both sublattices, only three of the four possible liquidus equations are independent on account of the equilibrium among the four compound components. The required binary compound activities in the quaternary solution are deduced from a statistical treatment of a regular mixture of four kinds of atoms subject to the site restrictions of the zinc-blende lattice. The calculation of quaternary phase diagrams from binary and ternary data is discussed. Finally, it is found for the case of mixing on both sublattices that previous results, based on the decomposition of the quaternary solid solution into a binary regular mixture of ternary solids, are consistent with the present analysis. 相似文献
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Jhumpa Adhikari 《Phase Transitions》2013,86(5):516-530
Current methods used to model the solution thermodynamics of III–V compound semiconductors involve the use of the valence force field as the molecular model and the regular solution model (with the temperature independent interaction parameter and underlying assumption of random mixing) as the engineering model. In this study, excess free energy models (with three or less adjustable parameters) are investigated to predict the solid–solid miscibility of (InAs) x (GaAs)1? x . The models investigated include the Porter/one-constant Margules (OCM) model, the two-constant Margules (TCM) model and the non-random two liquid (NRTL) model. These models are fit to excess free energy values derived from free energy change of mixing (variation with composition) data available from molecular simulations at different temperatures. The parameters in all the models have been found to be temperature dependent. The coexistence compositions are best predicted by the NRTL model, indicating the need to consider non-random mixing effects present in these solid solutions. The TCM model predicts better equilibrium composition data as compared to the OCM model. 相似文献