共查询到18条相似文献,搜索用时 812 毫秒
1.
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。 相似文献
2.
为了探究不同二次进气角度对流化床太阳能颗粒接收器内颗粒流动特性的影响,采用了欧拉-欧拉双流体模型与非均质过滤曳力模型(filtered)耦合的数值计算方法,数值模拟了30°,45°和60°〖KG*3〗3种二次进气角度下接收器内颗粒浓度及颗粒速度的分布。结果表明:与均匀曳力模型(Gidaspow和Wen Yu)相比,非均质过滤曳力模型计算结果与实验结果具有较好的一致性;在3种二次进气角度下,颗粒沿径向均呈现出边壁附近的颗粒体积分数高于中心区域的“环-核”非均匀径向分布,且两侧壁面的颗粒流向中心区域形成循环,同时伴随着颗粒团聚现象;相比于二次进气角度30°和60°,当二次进气角度为45°时,二次进气入口截面颗粒分布相对均匀,且不存在颗粒返混回二次进气入口的现象。 相似文献
3.
4.
研究了自然循环锅炉膜式水冷壁管的传热,采用编制程序对水冷壁进行温度场分布的计算,在研究方法上考虑了欠热沸腾起始点的问题,探讨了入口工质状态、炉内热流密度、质量流量、质量舍汽率等对水冷壁温度的影响。计算结果表明,入口水温的变化会影响欠热沸腾起始点的高度,但对温度的影响较小;炉内热流密度、质量流量和质量舍汽率的波动都会对温度产生影响,这主要是由于它们影响了换热系数的大小。 相似文献
5.
6.
采用数值模拟的方法,针对某台900 t/d高热值垃圾焚烧炉,研究前后拱角度、烟道位置对炉内燃烧过程、温度场、速度场、烟气主要组分分布及污染物排放特性的影响。结果表明:适当降低前拱角度有利于气流扰动和混合,强化传热和提高燃料燃尽率,提高后拱角度有利于增加烟气停留时间,促使热解后的可燃气体燃烧充分,提高热效率。前拱角度为21°,后拱角度为35°时炉内获得最佳的流场分布。烟道上移将增大炉膛容积,降低容积热负荷,出口烟气温度降低。烟道下移,炉膛容积减小,烟气在炉膛内的停留时间降低,烟道温度升高。烟道左右偏移容易造成温度场分布不均、水冷壁高温腐蚀等现象。从烟道模型中得到了最佳气流分布场和低的排放值。 相似文献
7.
8.
基于CFD的焙烧炉技术改进 总被引:2,自引:0,他引:2
基于计算燃烧学的原理和CFD软件对燃烧重油的焙烧炉炉内的流动和燃烧过程进行了数值模拟计算,讨论了炉内温度场、流场的分布规律,分析了结构因素对焙烧炉内流动和燃烧分布的影响.从炉子结构的设计角度提出了解决炉内温度场、流场的分布不均匀的方案.研究表明,在设计焙烧炉时合理地布置拉砖的位置有利于改善炉内流动和燃烧的分布. 相似文献
9.
建立步进式加热炉内流动、燃烧和传热的数学模型.炉内流场的模拟采用κ-ε双方程模型,辐射换热计算采用P-1辐射模型,气相燃烧采用Species Transport模型,流场计算采用Simpler算法.采用上述模型与算法得到了炉内详细合理的温度、速度和浓度分布,并对其中影响板坯加热的温度场进行了试验验证. 相似文献
10.
11.
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. 相似文献
12.
13.
14.
《International Journal of Heat and Mass Transfer》2007,50(19-20):3740-3748
A mathematical heat transfer model for the prediction of heat flux on the slab surface and temperature distribution in the slab has been developed by considering the thermal radiation in the furnace chamber and transient heat conduction governing equations in the slab, respectively. The furnace is modeled as radiating medium with spatially varying temperature and constant absorption coefficient. The steel slabs are moved on the next fixed beam by the walking beam after being heated up through the non-firing, charging, preheating, heating, and soaking zones in the furnace. Radiative heat flux calculated from the radiative heat exchange within the furnace modeled using the FVM by considering the effect of furnace wall, slab, and combustion gases is introduced as the boundary condition of the transient conduction equation of the slab. Heat transfer characteristics and temperature behavior of the slab is investigated by changing such parameters as absorption coefficient and emissivity of the slab. Comparison with the experimental work show that the present heat transfer model works well for the prediction of thermal behavior of the slab in the reheating furnace. 相似文献
15.
《International Journal of Heat and Mass Transfer》2007,50(3-4):412-422
A numerical analysis was carried out in order to investigate the combustion and heat transfer characteristics in a liquid rocket engine in terms of non-gray thermal radiation and soot formation. Governing gas and droplet phase equations with PSIC model, turbulent combustion model with liquid kerosene fuel, soot formation, and non-gray thermal radiative equations are introduced. A radiation model was implemented in a compressible flow solver in order to investigate the effects of thermal radiation. The finite-volume method (FVM) was employed to solve the radiative transfer equation, and the weighted-sum-of-gray-gases model (WSGGM) was applied to model the radiation effect by a mixture of non-gray gases and gray soot particulates. After confirming the two-phase combustion behavior with soot distribution, the effects of the O/F ratio, wall temperature, and wall emissivity on the wall heat flux were investigated. It was found that the effects of soot formation and radiation are significant; as the O/F ratio increases, the wall temperature decreases. In addition, as the wall emissivity increases, the radiative heat flux on the wall increases. 相似文献
16.
An investigation of the combustion of pulverized coal-air mixture in different combustor geometries 总被引:1,自引:0,他引:1
A two-dimensional theoretical study of the flow and combustion of pulverized coal by diffusion flames is presented. The model predicts gas flows, species concentrations, and temperatures in combustors having specific geometries. The conservation equations are solved utilizing the κ-ε turbulence model. Coal devolatilization is modeled by the two-competing-reactions scheme, which generates two sets of volatiles and char, each by a specific rate constant, described in Arrhenius form. Char combustion from devolatilization occurs by reaction with oxygen, carbon dioxide, water, particle dispersion, and radiative heat transfer between furnace wall and particles. The model is used to investigate the interaction between flow and combustion in flames produced by arranging the locations of the primary inlet and the secondary air inlets in a furnace. The predictions, which could be valuable for designing furnaces, indicate that a centered primary inlet and a minimum recirculation are some of the criteria that could favorable for combustion. 相似文献
17.
切圆燃烧锅炉炉膛传热过程综合模型及模拟计算 总被引:2,自引:0,他引:2
本文针对大容量煤粉锅炉的特点,对炉内各过程的数值模拟提出切合实际简化模型,用假想面有效辐射分析法模型计算内辐射传热,应用理想反应器的串并联网络模拟炉内宏观流动-燃烧过程,从而建立了适合于任意形状炉膛的传热计算综合模型,通过对一台670T/H锅炉进行的实例计算,对模型的准确性和实用性进行了初步验证,得到了较满意的结果。 相似文献