新型空气重介质流化床分选特性研究

为了提高空气重介质分选设备的可靠性,用振动代替刮板输送重产物,在自制新型空气重介质流化床小试装置上对物料分选特性与重产物输送行为进行了试验研究,考察了风量和抛掷指数对可能偏差、分选密度和重产物排出效率的影响.结果表明:风量与抛掷指数共同影响着分选效果,随着风量和抛掷指数的增大,重产物排出效率增大;随着风量的增大,分选密度减小,最后趋于稳定.在最佳分选条件下,可能偏差E值为0.045 g/cm3,分选密度为1.77 g/cm3,重产物排出效率为54%.     

采用空气重介流化床选煤技术分选高密度无烟煤的研究

针对高密度老年无烟煤的煤质特征与分选要求，本文从理论分析和实验研究两个方面论述了采用空气重介流化床干法选煤技术分选高密度老年无烟煤的结果。     

A stochastic model of bubble distribution in gas-solid fluidized beds

On the basis of the Langevin equation and the Fokker-Planck equation, a stochastic model of bubble distribution in a gas-solid fluidized bed was developed. A fluidized bed with a cross section of 0.3 m×0.02 m and a height of 0.8m was used to investigate the bubble distribution with the photographic method. Two distributors were used with orifice diameters of 3 and 6 mm and opening ratios of 6.4% and 6.8%, respectively. The particles were color glass beads with diameters of 0.3, 0.5 and 0.8 mm (Geldart group B particles). The model predictions are reasonable in accordance with the experiment data. The research results indicated that the distribution of bubble concentration was affected by the particle diameter, the fluidizing velocity, and the distributor style. The fluctuation extension of the distribution of bubble concentration narrowed as the particle diameter, fluidizing velocity and opening ratio of the distributor increased. For a given distributor and given particles the distribution was relatively steady along the bed height as the fluidizing velocity changed.     

颗粒的双极带电与气固流化床中的静电分布

对颗粒的双极带电现象和气固流化床中的静电分布进行了理论分析和实验研究．推导出了小颗粒上电荷量的计算公式,指出大小颗粒的带电极性由颗粒表面上的电荷载流子类型决定,若绝缘颗粒表面上的电荷载流子为电子或阴离子,则大颗粒带正电,小颗粒带负电;反之大颗粒带负电,小颗粒带正电．在150 mm的有机玻璃流化床冷模装置中,以干燥氮气为流化气体,对LLDPE、HDPE、PP1、PP2和PVC等5种聚合物粉料系统,测量了不同气速下流化床中不同床高处的静电压值．结果发现床内的静电场为非均匀电场,静电压沿床层轴向呈“Z”型或“S”型分布,且在床层稀密相分界面附近会发生极性的改变,实验验证了颗粒的双极带电理论．     

Mechanism and application of coal dry beneficiation with air-dense medium fluidized bed

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空气重介流化床干法选分配曲线数学模型研究

借鉴湿法选分配曲线数学模型，研制出空气重介流化床干法选分配曲线的最佳数学模型——复合ＬＯＧＩＳＴＩＣ－ＧＯＭＰＥＲＴＺ模型，通过大量的计算机模拟工作，验证了该模型的可行性。     

Process of back pressure deep drawing with solid granule medium on sheet metal

The experimental die apparatus of the solid granules medium forming on sheet metal was designed and manufactured.Typical parts,such as conical,parabolic,cylindrical and square-box-shaped components,were successfully trial-produced as well.According to the analysis of the changing trends of the cross-section shape and the wall thickness during the process,it can be found that the shape of the free deformation zone of the sheet metal,which is the most critical thinning area,can be described as an approximately spherical cap.According to this forming feature,back pressure deep drawing technology with solid granules medium on sheet metal was proposed to restrain drastic thinning at the bottom of the part through the joint friction effect of solid granules medium,the back pressure tringle and the sheet metal.Therefore,the deep drawing limit of the sheet metal is significantly improved.In order to fabricate thin-walled rotary parts with great drawing ratio and complex cross-sections,a finite element model based on the material property test of the solid granules medium was established to optimize the scheme of the back pressure deep drawing.The effects on the forming performance of sheet metal from back pressure load and the approach of blank holding control were analyzed through this model.     

超超临界汽轮机中压转子冷却效果分析

为了评价超超临界汽轮机中压转子的冷却效果及其对主蒸汽流动性能的影响,以600MW超超临界汽轮机中压缸为计算模型,采用气热偶合数值模拟方法对中压转子的蒸汽冷却进行了研究.计算结果表明,在所研究的冷却结构与冷却蒸汽初参数下,叶根最高与最低温度分别下降19K与95K,中压转子得到了充分冷却.冷却蒸汽增大了动叶温度分布的不均匀性,导致热应力上升.因此有冷却的动叶热应力校核应该是一个重点考虑的问题.     

多点成形过程中弹性介质对成形质量的影响

应用动态显式有限元算法对使用弹性介质的多点成形过程进行数值模拟研究，分析成形过程中产生的压痕缺陷．弹性介质的厚度和弹性模量等参数是影响成形性能的重要因素；对不同厚度和弹性模量的弹性介质在成形过程中对压痕的抑制作用进行对比分析，探讨合适的弹性介质参数．     

中速磨煤机入口一次风量数值模拟

某燃煤电厂1#机组在调试期间,发现由于磨煤机入口风量测量值波动较大,导致一次风量自动调节装置不能正常投运.分析了磨煤机入口一次风量测量产生误差的原因,通过对磨煤机入口一次风道流场的数值模拟,找到了风道内的涡流区,并采用在风道内加装紊流栅的方法,对1#机组磨煤机一次风量测量装置进行了改造,并取得了良好的效果.     

中速磨煤机入口一次风量数值模拟

某燃煤电厂1#机组在调试期间,发现由于磨煤机入口风量测量值波动较大,导致一次风量自动调节装置不能正常投运.分析了磨煤机入口一次风量测量产生误差的原因,通过对磨煤机入口一次风道流场的数值模拟,找到了风道内的涡流区,并采用在风道内加装紊流栅的方法,对1#机组磨煤机一次风量测量装置进行了改造,并取得了良好的效果.     

双流化床钙基吸收剂吸收CO2能量平衡研究

基于双流化床物质与能量平衡建立并耦合计算碳化炉与煅烧炉的物质与能量平衡关系式,分析了双流化床能量平衡及碳化炉飞灰份额、钙碳摩尔比、分离器效率等可变参量对其能量平衡的影响.结果表明:碳化炉水冷壁吸热量在x3=0.99,x10=0.95、x3 =0.95,x10=0.99及x3 =0.99,x10=0.99三种工况下随钙碳...     

Occurrence characteristics of mercury in high-mercury coal and distribution rule of mercury in products of an air dense medium fluidized bed

Mercury emitted from direct combustion of high-mercury coal does great harm to the environment. To make good use of high-mercury coal, it is necessary to study the occurrence characteristics of mercury in coal and high-efficient methods of mercury removal. In this paper, high-mercury coal of Guizhou Province of China was taken as an object to study the nature of mercury in coal and the rule of mercury removal by dry preparation method. Mercury mainly distributes in the medium and high density fractions, and has a good affinity with silicon, aluminum, iron, titanium, potassium, calcium, zinc, sodium and magnesium. It exists in minerals formed by these elements and presents significant correlation with ash in coal. After the high-mercury coal is separated by air dense medium fluidized bed, mercury content of clean coal is reduced to 1/10 of raw coal, while mercury content of gangue is increased to 3 times that of raw coal. This indicates that mercury in raw coal is rejected greatly by ADMFB and enriched in highdensity fractions. The rates of ash removal and mercury removal decrease with the density and present a very high correlation.     

闭式循环条件下内燃机燃油和工质物性计算

针对闭式循环条件下,缸内工质的特殊构成,提出用正十六烷和α-甲基萘按适当比例混合的混合物来模拟燃油,认为缸内燃烧过程的气态工质由氧气、氮气、水蒸汽、二氧化碳、氩气、正十六烷和α-甲基萘所组成。同时,给出了燃油和缸内工质物性计算所应采用的方法。经验证,方法是正确的、可行的。     

内燃机工作过程燃油和工质物性计算

针对燃油及缸内工质所处状态，提出了内燃机燃油和缸内工质物性计算所应采用的方法，经验证，该方法是正确的、可行的。     

高分散性固体聚氨酯磁带胶的制备

研究了含-SO3Na基团的固体聚氨酯磁带胶的合成工艺条件，即原料配比、反应温度、反应时间、分子量，以及-SO3Na基团含量等因素对提高磁粉分散性的影响．并与不含-SO3Na基团的聚氨酯磁带胶进行对比，得到-SO3Na基团含量为0．70％。1．00％(质量分数)时，对磁粉的分散性有显著提高．     

嵌入不透水球体复合多孔介质渗流场分析

嵌入不透水球体的复合多孔介质广泛存在于地下水渗流领域,由于不透水球体的影响,多孔介质中的水在流经不透水球体时发生绕流,且距离球体越近绕流现象越明显。为求解该复合介质的渗流场和等效渗透系数,在球坐标系下采用非线性Brinkman-extended Darcy方程,以无穷远处单向来流均匀和球面不滑移条件作为边界条件,求解出球体周围渗流流速与压强的解析解。分析该解析解表达式可知,此复合介质渗流场流速和压强分布与多孔介质基质的渗透率和地下水动力粘滞系数有关。在此基础上对渗流场流速进行积分,求出了Darcy流平均流速,并将平均流速表达式与Darcy公式表达式进行对比,得出等效渗透系数表达式,并且理论证明球体与多孔介质的相对尺寸是影响复合介质等效渗透系数的最主要因素。最后以一定级配的砂作为多孔介质基质,用直径分别为4cm、6cm、8cm的三种有机玻璃球体作为不透水球体,自制试验装置,开展了嵌入不透水球体复合多孔介质的常水头渗流试验。试验中控制多孔介质基质的压实度来保证其渗透系数基本不变,改变填充在多孔介质基质中的不透水球体进行渗流试验,对每一个不透水球体分别进行三组试验,取平均值作为试验结果。试验结果与理论计算的等效渗透系数值误差较小,验证了所推求嵌入不透水球体复合多孔介质渗流场的正确性。     

饱水冻土水热力耦合分析

冻土在冻结、融化的过程中,伴随着土中水的冻结和融化,土的体积也随之发生变化。这种体积变化常常造成寒区建筑的破坏。为解决工程实践问题,本文提出了“三场”耦合分析的一般数学格式来模拟分析冻土冻结过程,并采用有限元思想导出相应的时空离散化方程,给出了非线性数值求解的迭代计算步骤。另外,文中给出具体的数值算例,以验证本文方法的可靠性、有效性和计算精度。     

SF6灭弧室内流场数值模拟软件化

求解流体N－S方程是数值计算中较为复杂的一种,基于Windows操作系统,把以ALE为基础的变形流体法推广应用到断路器灭弧室内,形成一种新方法－－变形流体网格步法,并进行了气流分析,把数据化作各种各样的图像,利于有效地判断计算结果的正确性和特性,进而了解流场的各种特性,为了提高程序的通用性和实用性,使一般工程技术人员能够使用,对于前处理,主程序和后处理部分进行了处理,使计算程序在向通用化,商业化的方向上迈进一步。