燃煤气单元玻璃熔窑火焰空间数值模拟

通过建立火焰空间三维数学模型来模拟燃煤气单元玻璃熔窑火焰空间内的流动、燃烧、传热等过程。针对煤气的燃烧特点，单元窑的火焰特征等进行了较深入的研究。结果表明，该三维数学模型能够比较全面地反映火焰空间速度场、温度场分布的规律；模型具有通用性好，不易受环境波动影响的优点，具有一定的实用意义。     

全氧燃烧喷枪火焰空间气流场温度场的数值模拟

利用数值模拟方法,选用标准k-ε湍流模型、涡一耗散化学反应模型、p1辐射传热模型,研究了玻璃熔窑在全氧燃烧条件下助燃气体氧含量对喷枪火焰空间气流场和温度场的影响规律.结果表明,进油口尺寸、重油蒸汽速度和进气口尺寸一定.增大助燃气体氧舍量,有助于提高燃烧速率,使得尾气排放量及其带走热量减小.火焰空间温度场分布梯度变大.火焰温度增高.结果表明,所选用的三维数学模型能够比较全面地反映火焰空间气流场、温度场分布规律,这对于全氧燃烧在玻璃熔窑中的应用和研究,特别是氧枪的设计与操作,工艺制度的优化具有一定的理论和实践意义.     

全氧燃烧浮法玻璃熔窑窑压的数值模拟

采用基于k-ε湍流模型、涡-耗散化学反应模型、P1辐射传热模型的数值模拟方法,研究了玻璃熔窑在全氧燃烧条件下烟气出口面积对窑内压力场和火焰空间的影响规律。研究结果表明,所选用的三维数学模型能够较为真实的反应全氧燃烧玻璃熔窑火焰空间的状态。随着烟气出口面积的增加,玻璃熔窑内压力下降,窑内平均压力与烟气出口面积符合指数衰减关系。当单侧烟气出口面积为0.36 m2时,窑内平均压力约为6 Pa。烟气出口面积改变对火焰形态以及温度场的影响不明显。因此改变烟气出口面积可以作为有效调节全氧燃烧浮法玻璃熔窑窑内压力技术手段,这为指导全氧燃烧玻璃熔窑的设计和运行提供了理论依据。     

不同富氧含量玻璃熔窑火焰空间温度场的对比

建立了玻璃熔窑火焰空间温度场的三维数学模型，通过对某日产400t燃油浮法玻璃熔窑火焰空间在三种富氧情况(氧含量分别是24％，27％，30％)下用图像模拟直观的表述出计算结果。模型包括气相流动与传热模型，雾化油滴燃烧的轨道模型，和辐射传热模型。程序采用MS-FORTRAN语言，绘图采用Stanfordgraphic软件。对比结果表明，随着富氧含量的增加，各小炉火焰长度明显缩短，温度显著提升，模拟结果对窑炉设计与富氧燃烧组织有一定的参考价值。     

横火焰玻璃窑炉燃烧空间流动与传热的数值模拟

对横火焰玻璃窑炉燃烧空间内的流动、燃烧及辐射传热等过程进行了数值模拟研究,建立了玻璃窑炉燃烧空间内的综合数学模型,给出了诸控制方程的统一的数值解法,得到了炉内燃烧空间的速度场、温度场、组分浓度分布及燃烧空间向玻璃液面传递的热流分布。     

不同含氧量下玻璃窑炉火焰空间温度场及流场的模拟研究

采用Design Molder三维建模软件建立玻璃窑炉火焰空间的三维模型,利用ANSYS Fluent18.0对不同含氧量条件下对玻璃窑炉火焰空间温度场及流场进行模拟研究。研究结果表明随着氧气含量的增加,火焰空间内温度场及速度场呈先增加后减小趋势,当喷枪口内氧气的含量在0.8左右时,火焰空间内温度及速度达到最大值,但此时火焰空间内的水蒸气浓度相对较低,可以减少耐火砖的侵蚀作用。模拟分析的结果为优化窑炉的火焰空间设计,延长窑炉使用寿命提供了理论指导。     

马蹄形火焰玻璃熔窑燃烧空间流动与传热的数值模拟

对马蹄形火焰玻璃窑炉燃烧空间内的流动、燃烧及辐射传热等过程进行了数值模拟研究,得到了炉内燃烧空间的速度场、温度场、组分浓度分布及燃烧空间向玻璃液面传递的热流分布。探讨了燃烧空间入口的进气角度对炉内温度场和向玻璃面传递的热流的影响,模拟结果表明,当入口的进气角度在5°～10°之间时,传热效果较好。     

玻璃熔窑火焰空间的三维数值模拟

采用计算流体力学软件CFD,加载k-ε湍流模型、渦耗散反应模型与DO辐射模型。通过编写UDF函数将玻璃液面与火焰空间底部进行单向耦合,从而获得了玻璃熔窑火焰空间的温度及速度变化规律,将模拟分析的结果与工业试验数据进行对比验证,验证了模拟的可靠性。为优化窑炉的火焰空间设计,提高玻璃制品的熔制质量,改善生产条件提供了理论依据。     

浮法玻璃熔窑熔化池底部横向宽度对熔化池温度场影响的研究

基于计算机数值模拟方法,以460 t/d浮法玻璃熔窑为模拟对象,分析研究了不同熔化池底部横向宽度对玻璃熔窑的生产能力以及熔窑内玻璃液温度场的影响。结果表明,适当减小熔化池底部横向宽度不会明显改变卡脖和冷却部的玻璃液状况,从而不影响熔窑的生产能力。但不同的熔化池底部横向宽度将导致熔化部玻璃液温度场发生改变,中轴面处玻璃液温度降低,而胸墙处玻璃液温度升高,导致窑内玻璃液横向温度梯度发生相应变化,加剧玻璃液横向对流,有助于玻璃液均化和澄清。     

燃气轮机双燃料燃烧室温度场优化研究

为了优化双燃料燃烧室温度场分布,针对某型逆流环管双燃料燃烧室,设计了3种不同的火焰筒配气结构。利用ANSYS FLUENT软件,选用Realizable k-epsilon湍流模型及Finate Rate Chemistry and Eddy-disspation燃烧模型对燃烧室额定工况下的温度场及速度场进行了数值模拟。研究表明:对比液体燃料,由于气体燃料扩散较快,燃烧室在使用气体燃料时高温区分布周向收缩并沿火焰筒轴向后移。对于本型燃烧室,适当增大主燃孔孔径并在火焰筒轴向方向偏后布置,可以有效解决双燃料燃烧室使用气体燃料时高温区后移的问题,对气/液两种燃料条件下的温度场组织更为有利。     

Experimental and numerical study on the flow fields in upper furnace for large scale tangentially fired boilers

Experimental and numerical study on the aerodynamic field has been carried out in a tangentially fired boiler model of a 600 MW unit, with emphasis on the flow fields in upper furnace and the gas velocity nonuniformity in horizontal flue gas pass. The results show that there exists residual swirl intensity of nearly 20% at the entry of the plate zone in upper furnace for large scale tangentially fired boilers. And the flow fields are obviously different in the left and right sides of upper furnace and the gas velocity deviation is large in horizontal flue gas pass. Moreover, some new furnace arch structures and arrangements of division platen superheaters are proposed to effectively alleviate gas velocity deviation in horizontal flue gas pass for large scale tangentially fired boilers. The numerical results agree well with the experimental ones, which can give a good insight into the flow characteristics in upper furnace and a clear explanation on the forming mechanism of flue gas velocity and temperature deviation for large scale tangentially fired boilers.     

Eulerian approach for multiphase flow simulation in a glass melter

A glass furnace, consisting of a combustion space and a glass melter, uses combustion heat to melt sand and cullet into liquid glass to make products. Glass quality is mainly dependent on the temperature, glass composition, and the level of impurities in a glass melter, which include solid batch/cullet particles, liquid glass, and gas bubbles. A comprehensive computational model using an Eulerian approach has been developed to simulate multiphase flows in a glass melter. It includes all the phases, divides solid particles or gas bubbles into various size groups, and treats each group as a continuum. The derived mass, momentum, and energy conservation equations of the flow are solved for local properties for each phase. The simulation considers the heating and melting of the batch (mainly from the radiative heat from combustion and from the convective heat from the molten glass), the formation and transport of bubbles, and the heating and mixing of the liquid glass. The approach was incorporated into a multiphase reacting flow computational fluid dynamics code that simulates overall glass furnace flows to evaluate the glass quality and furnace efficiency.     

Three-dimensional modeling of utility boiler pulverized coal tangentially fired furnace

This paper presents selected results of numerical simulations of processes in utility boiler pulverized coal tangentially fired dry-bottom furnace. The simulations have been performed by specially developed comprehensive mathematical model. The main features of the model are a three-dimensional geometry, k–ε gas turbulence model, Eulerian–Lagrangian approach, particles-to-turbulence interaction, diffusion model of particle dispersion, six-flux method for radiation modeling and pulverized coal combustion model based on the global particle kinetics and experimentally obtained kinetic parameters. Five operation regimes of 210 MW_e boiler furnace burning Serbian lignites, with different grinding fineness of coal and coal quality, have been simulated. The model successfully predicts the influence of the parameters on the furnace processes and operation characteristics (like the flue gas temperature and the furnace walls radiation fluxes). The predicted flame temperature and percentage combustibles in bottom ash are in good agreement with the measurements. The developed model can find different applications, both in research and practice.     

WNS型燃油(气)锅炉炉内热流分布及温度分布的数值模拟

利用计算流体力学软件对WNS型卧式内燃燃油（气）锅炉内的流动，传热、传质进行了数值模拟，分别采用天然气和轻柴油为燃料，对炉膛内的热流分布，温度分布进行了比较分析，为WNS型锅炉的开发和设计提供了有效的研究手段。     

Assessment of a novel numerical model for combustion and in-flight heating of particles in an industrial furnace

The key factors for efficient in-flight particle heating in a combusting flow were investigated within this paper for the development of a novel boiler slag bead production furnace. A natural gas fired industrial burner with a thermal input of 1.2?MW was thus evaluated using Computational Fluid Dynamics (CFD). The steady laminar flamelet model (SFM) and a detailed chemical reaction mechanism, considering 25 reversible chemical reactions and 17 species were used to account for the steady-state gas phase combustion. Measurements of gas temperature and flow velocity within the furnace were found to be in good accordance with the numerical results. In the second step, sintered bauxite beads were injected into the furnace as an experimental material and heated up in flight. The particle heating characteristics were investigated using the Discrete Phase Model (DPM). The computational results of the particle laden flow raised the issue that convective heat transfer is a key factor for efficient particle heating. At the burner chamber outlet, the temperature of a particle which had been injected into the burner flame was 178?K higher compared to a particle, which trajectory led through zones with lower gas temperatures.     

Control of ash related problems in a large scale tangentially fired boiler using CFD modelling

The objective of this study is to develop a three-dimensional combustor model for predicting the performance of full-scale tangential fired (TF) boiler and to determine the flow patterns of the gas and coal particles, with an emphasis on formation mechanism of gas flow deviations and uneven temperature on the super-heaters, re-heaters and divisional super-heater sections of the furnace. The importance of these simulations is to identify the locations of optimum additive injection ports to achieve maximum impact of additives in the combustion process to minimize the temperature deviation and reduce ash-related issues. This study is a classic example of numerical investigation into the problem of turbulent reacting flows in large scale furnaces employed in thermal power plants for the remediation of ash deposition problems. Present work also provides an investigation of the influence of number of tripped burners on the characteristics of the flow and thermal fields. Excellent agreement between the simulation results and key boiler design values and available site operation records following full-scale trials indicate that the calculations are reliable. The results obtained from the present work are directly relevant to coal-fired utilities for not only demonstrating the effectiveness of computational fluid dynamics (CFD) based tools in combating operational issues but also provides an alternative to conventional remediation strategies.     

Effect of heavy fuel oil/natural gas co-combustion on pollutant generation in retrofitted power plant

The purpose of this paper is to examine effect of co-combustion of heavy fuel oil and natural gas on the pollutant formation: CO₂, SO₂, SO₃, NO_X and soot. The analysis was carried out by means of numerical simulation on the case of retrofitted steam generator furnace of Thermal Power Plant Sisak (Croatia). Comprehensive mathematical model of the furnace with detailed 3D mesh was set up to include all relevant aerodynamic and thermo-chemical processes in the furnace. Dedicated model for SO₃ formation was developed earlier and used in this work. By increasing the natural gas contribution in overall fuel fired in the furnace, emissions of CO₂, SO₂, soot, NO_X and SO₃ decreased. Heat transferred to the furnace walls and temperature field in the furnace were also examined in order to establish regions of safe and efficient boiler operation for different operational regimes.     

四角切向燃烧锅炉水平烟道烟温偏差形成机理的研究

以 HG-2 0 0 8/1 8.2 -YM2型四角切向燃烧锅炉为原型进行冷态模化试验 ,采用热线风速仪测量了上部炉膛及水平烟道内的流场 ,研究了上部炉膛屏区气流速度分布特点 ,分析了水平烟道内烟气速度偏差和温度偏差的形成机理 ,为科学地分析过热器、再热器超温爆管的原因和减小水平烟道烟气温度偏差提供参考。图 9表 1参 4