元胞自动机方法模拟干熄炉内焦炭颗粒的下降运动

干熄焦工艺中干熄炉内焦炭下降运动对熄焦质量起着至关重要的作用.利用元胞自动机方法(CA)的基本理论,采用能较好模拟各向同性现象的正三角形网格划分研究区域,邻居处理为Moore方式,模拟实验干熄炉内焦炭颗粒的运动,得到了下降料面曲线,并与实验结果进行了对比分析.研究表明,计算值和实验数据趋势一致,元胞自动机方法基本上能够准确地反映炉型变化和风帽对焦炭下降运动的影响,若能进一步考虑颗粒之间、颗粒与壁面之间的相互作用力,将有利于提高模拟的精度.     

干熄炉内环形集气道压降及阻力系数的研究

借助CFD商业软件CFX数值模拟了干熄炉环形集气道内气体的湍流流动,并计算了各斜道区的压力分布。计算结果与现场实测数据吻合较好,验证了数值模拟的准确性。借鉴管路计算中局部阻力系数的概念,进一步计算了斜道区不同压砖情况下的压力损失系数。三种几何尺寸模型的计算结果表明,所得到的压力损失系数具有一定的通用性,可为干熄炉大型化环形集气道的设计提供参考。     

干熄炉风帽供风压力损失的数值研究

干法熄焦的核心技术是干熄炉内焦炭的冷却过程,而此过程是否能够顺利进行的关键之一是布风的好坏.干熄炉内的布风受很多因素的影响,如风帽的几何形状和安装的位置,环形烟道的几何形状等等.对实验干熄炉内的风帽供风采用CFX计算流体力学商业软件进行数值模拟,重点研究了三种风帽供风条件下的压力损失,并计算出了每种风帽的阻力系数;针对每一种风帽,考察了横向压砖和纵向压砖对供风的影响.研究结果表明:对各种风帽,压砖情况下的阻力系数大于不压砖的情况;椭圆风帽的阻力系数远远大于高风帽和低风帽的阻力系数;风帽出口局部地方存在负压倒吸现象.     

转捩模型在叶栅粘性流数值模拟中的应用方法研究

通过求解N—S方程对流场进行数值模拟，已成为研究透平机械的一个重要手段。而建立合适的转捩模型能够使流场数值模拟更为准确。本文作者利用现有的试验数据对Abu—Ghannam and Shaw^[1]转捩模型(AGS转捩模型)进行了修正，提出了利用弧长雷诺数模型确定转捩区长度的思想，并对计算结果与试验值进行了比较。     

转捩模型在静叶栅三维粘性流数值模拟中的应用研究

边界层转捩流动的特征参数明显不同于层流或湍流，转捩流动的这些特征直接影响着流体的动力、传热特性。而通过有效地控制转捩起点、转捩区长度就可以有效改善流动效率。作者将修正的转捩模型应用到实际流场计算中，对计算结果进行了比较，从中得到了一些有意义的分析结果。     

燃烧反应干熄炉内传热模拟的浅析

建立了干熄炉内焦炭层床循环气体的传热模型,并耦合燃烧反应计算,分析了干熄炉冷却室内的温度变化,计算结果与实测数据基本一致。本文还进一步分析了化学反应活化能、风料比和燃烧反应对干熄炉内传热的影响,以期为干熄炉的优化设计提供一定参考。     

干熄炉内流动和传热过程数学模型的研究现状及其发展趋势

全面系统地综述了国内外有关干熄炉内流动和传热过程数学模型的研究现状及其发展趋势。其中，利用多孔介质理论建立的干熄炉内流动与传热过程数学模型能够比较真实地揭示干熄炉内气体流动和气固之间的换热规律，已成为干熄炉的优化设计及其最优控制的理论基础。     

干熄炉料钟布料焦炭粒度分布的研究

对于干熄焦工艺,为了改善焦炭在干熄炉径向方向上的粒度偏析,采用料钟进行布料。采用实验和理论模拟相结合的分析方法,对布料焦炭在干熄炉预存段粒度偏析机理进行了研究。实验制作了冷态三维半圆料钟布料模型,考察了不同形状的料钟和不同的料线深度对焦炭粒度在干熄炉半径方向上分布的影响。所采用的理论模拟数学模型针对多尺度焦炭颗粒情况,用极少的参数来模拟半径平均尺度分布和每一种颗粒的半径堆积分布。研究结果表明,实验数据和数值分析结果吻合较好,相互验证了实验和理论模拟的正确性与可靠性。     

不同湍流模型对水平轴风力机三维粘性气流特性的影响

对某水平轴风力机叶片附近的三维湍流流场进行了数值模拟,其中在7、15、25m/s 3种不同工况下分别采用S-A、Standard k-ε、RNG k-ε和SST k-ω4种湍流模型。计算结果表明:随着来流速度的逐渐增大,叶片吸力面的分离流沿叶根向叶尖方向逐渐发展,且由于三维旋转效应使得展向流动逐渐增强。和相关实验结果比较,选择不同的湍流模型对数值模拟结果有明显影响,其中RNG k-ε和SST k-ω两种模型可以获得较好的压力分布计算精度。综合考虑压力分布、功率系数和推力系数在不同工况下与实验结果的比较,选择SST k-ω湍流模型较适合模拟该水平轴风力机周围复杂的三维湍流流动。     

干熄炉内传热和流体流动的数学模型

干熄焦工艺具有节能和环保双重效益，其基本原理是利用循环惰性气体冷却焦炭。根据多孔介质理论，采用非达西流和非局域热平衡方法，建立了干熄炉内流体流动和传热的数学模型，并采用基于非正交同位网格的SIMPLE方法求解对流扩散方程，通过数值求值，得到了干熄炉内气体速度，压降以及气体和焦炭的温度分布规律，计算结果表明熄焦过程解决焦炭温度偏析的关键是改善布料时焦炭粒度分布的均匀性。     

干熄焦红焦烘炉的研究与应用

本文着重阐述了干熄焦红焦烘炉的理论依据、原理、方案等,并对红焦烘炉和煤气烘炉的实施效果进行了评价比较,指出了对年修后的干熄炉红焦烘炉的优点,这对焦化干熄焦系统具有很好的推广价值。     

Mathematical Model for Fluid Flow and Heat Transfer in the Cooling Shaft of Coke Dry Quenching Unit

IntroductionCoke Dry Quenching (CDQ) unit is a regenerativesystem whose thermal fUnchon is to cool off the red hotcoke with the circulahng gas and at the same time tOtransfer energy from the incandescent coke to watervapor fOr electricity generation. In comParison toconventional Coke Wet Quenching (CWQ) system, CDQenables not only energy savings, but also environmentalprotection. Further advantage is the imProved quality ofcoke. TherefOre, CDQ technology is becoming theconunon practi…     

Experimental study on the effects of blast‐cap configurations and charge patterns on coke descending in CDQ cooling shaft

The coke descending behavior in a CDQ cooling shaft is studied experimentally by means of a tracing method with a digital camera. For three different blast‐caps, the law of coke flow is studied under five conditions of coke charge. The experimental results show that, for the sake of the uniformity of the coke burden descending, a blast‐cap with elliptical cross‐section is a better choice than that with circular cross‐section regardless of high or low placement. A coke charge pattern with a flat top burden surface is preferable to that with peak‐valley surface, a double‐peak superior to a one‐peak. Trajectory and average velocity distribution of coke behavior are depend weakly on whether the coke is continuously fed or not as the discharging began. The blast‐caps have local effects on the descending coke and hardly affect whether the cokes flow smoothly or not in the case of coke burden with enough depth. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(6): 352– 358, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20212     

干熄锅炉内传热过程数学模型及其数值仿真

在详细分析了干熄锅炉内传热过程的基础上,建立了干熄锅炉内传热过程数学模型。采用现场实测数据对所建立的数学模型进行了验证。在此基础上,仿真计算了典型工况下的理论产汽量,并分析了影响干熄锅炉产汽量的诸多因素。所做工作对干熄炉一锅炉系统的计算机优化控制具有重要的指导意义。     

Computational and Experimental Study of Cooling Process in Coke Dry Quenching Experimental Shaft

Owing to its merits in energy savings, environmental protection and coke quality improvement, the Coke Dry Quenching (CDQ) technology is favorite in coke making industry today. In order to validate the mathematical model developed for the cooling process of real CDQ shaft, the one-seventh scale experimental setup was established. With the air as the working fluid and the coke as the packed bed, the coke and gas temperatures and the pressure drop in the cooling shaft were measured. A mathematical model based on the non-Darcian and non-thermal equilibrium model for the cooling process of the CDQ experimental shaft was presented. The computational results were compared to the experimental data. It was found that most numerical predictions were supported by the measured values.     

冷气孔流量对叶尖泄漏流动影响的研究

为研究冷气孔流量对涡轮叶尖泄漏流动的作用,采用数值模拟方法对比分析冷气流量比在0.05%～3%之间的三维流场和总压损失情况。结果表明：叶尖冷气可以有效地减小泄漏量和叶尖泄漏流动带来的总压损失,泄漏量下降达80%,总压损失峰值下降达38.2%;随着流量比的增加,叶尖冷气对叶尖主流泄漏流动的抑制效果不断增强,由主流带来的泄漏量不断减小;叶尖冷气也带来了新的总压损失,整体总压损失随着流量比的增加不断增大。叶尖冷气对叶尖泄漏的抑制模式分为3种：流量比在0.05%～0.1%之间,以降低主流泄漏流的能量减弱泄漏流动;流量比在1.25%～3%之间,以在叶尖区域形成完整的气膜屏障抑制主流泄漏流动,流量比在0.1%～1.25%之间,上述两种模式同时存在;流量比为1.25%时,冷气在叶尖区域形成一道完整的气膜屏障,阻碍主流流体形成泄漏流。     

涡轮导叶轴向弯曲对其气动性能影响的研究_三维粘流数值分析

近年来计算流体力学在叶轮机械中得了应用,在三维计算方法有了很大的进。与之同时,从学院式的研究到工业应用的过渡已经开始。中国科学院工程热物理研究所在最近二十年内致力于发展各种轮机械三维流动的计算方法。本文的目的是介绍作者的方法和应用它来研究分析一个典型的大长径比涡轮导向器气流流动的物理现象。本文给出了一些研究结果和建议。     

Viscous Potential Flow Analysis of Kelvin–Helmholtz Instability of a Cylindrical Flow with Heat and Mass Transfer

A linear analysis of Kelvin–Helmholtz instability of a cylindrical interface has been carried out when there is heat and mass transfer across the interface, using viscous potential flow theory. Both fluids are considered as incompressible, viscous, and thermally conducting with different kinematic viscosities. Both axisymmetric as well as asymmetric disturbances are considered. Stability criterion is given by a critical value of relative velocity and stability is discussed theoretically as well as numerically. Various graphs with respect to physical parameters such as wave number, viscosity ratio, heat transfer coefficients, Reynolds number, etc., have been drawn and the effect of various parameters have been described. A comparison with the linear stability analysis of inviscid fluids (Lee [10]) has been made and it is observed that viscosity has a stabilizing effect on the stability of the system. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(6): 489–503, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21092