共查询到20条相似文献,搜索用时 125 毫秒
1.
在冷态实验台和两台1025t/h锅炉上,利用等温模化方法对双调风旋流燃烧器的空气动力特性进行了冷态试验。试验表明:具有12个内二次风叶片的双调风旋流燃烧器回流区最大直径、长度与燃烧器最外层直径之比分别在1.38、1.48以上,扩展角大于80°,可卷吸足够的高温烟气及时引燃煤粉;在具有8个内二次风叶片时,没有回流区,扩展角在61.9°和69.5°之间,不利于稳定燃烧。采用较低的一次风率具有较大的回流区,有利于稳定燃烧。 相似文献
2.
作者提出采用正交射流燃烧器来代替钝体燃烧器,从而避免了钝体燃烧器的磨损和烧坏问题.经冷态空气动力学试验证明,交叉射流的足迹有一个明显的负压区存在,随着交叉射流速度比的增加.回流区的宽度、长度和质量回流率是增加的,射流的穿透深度也是增加的,它们对煤粉燃烧过程的稳定和强化起了有利的作用.在试验的基础上,归纳了有限空间内正交射流的流动规律和燃烧器的设计方法. 相似文献
3.
稳燃腔煤粉燃烧器的试验研究及应用 总被引:7,自引:0,他引:7
为了提高劣质煤燃烧稳定性,利用三维LDA测量了稳燃腔燃烧器回流区三维速度分布及湍流度分布,在单火嘴试验台上进行了燃烧试验,并在220t/h燃用劣质无烟煤锅炉上投入实际应用。燃烧试验和实际应用结果都表明,稳燃腔燃烧器对提高劣质煤燃烧稳定性具有很好效果。 相似文献
4.
5.
6.
7.
8.
9.
建立了花瓣燃烧器的物理模型,采用Fluent软件对不同一、二次风速度时花瓣燃烧器冷态下的流场进行了计算,分析了一、二次风配风方式对此种燃烧器出口流场的影响.结果表明:一次风的存在使回流区减小,稳燃能力降低,但能调整回流区与燃烧器出口的距离,避免了结渣等问题的发生;当一次风速度一定时,增大内二次风合速度,轴向回流区变大,能改善燃烧效果;调整内二次风叶片角度,增大内二次风切向速度,径向回流区变小,轴向回流区增大;针对不同的煤种,需选择适当的一、二次风速度,增大轴向或径向回流区以提高稳燃能力. 相似文献
10.
11.
Nitrogen oxide formation is one source of pollution emission in fossil fuel combustion. Numerous technologies, such as flameless combustion, have been introduced to prevent such formation. This paper presents a panorama of flameless combustion and its principles. The influence of this technology on air preheats and gas diluents is discussed, as well as the effect of the firing mode on thermal NOX. The benefits of flameless combustion, including its energy conservation capability and capability to reduce pollutant emissions such as NOX emission to overcome environmental dilemmas in combustion, are discussed in this paper. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
13.
The high energy density of hydrocarbon fuels creates a great opportunity to develop combustion based micro-power generation systems to meet increasing demands for portable power devices, micro unmanned aerial vehicles, micro-satellite thrusters, and micro chemical reactors and sensors. In this paper, the recent technological development of micro-power systems and progress in fundamental understanding of micro-scale combustion are reviewed. At first, micro-scale combustion regimes are categorized by using different physical and chemical length and time scales and the resulting non-dimensional parameters and their correlations to various combustion regimes for micro and mesoscale combustion are discussed. Secondly, the recent successful developments and technical challenges of micro-thrusters, micro internal combustion engines, and micro chemical reactors summarized. Thirdly, the underlying fundamental mechanisms and ignition and flame dynamics in micro-scale combustion are reviewed, respectively, in premixed, non-premixed, catalytic, and non-equilibrium, micro-scale combustion systems. The conventional concepts of combustion limits such as the flammability limit, quenching diameter, and flame extinction and heat recirculation are revisited. The unique thermal and chemical transport mechanisms such as flame structure interaction, radical quenching, non-equilibrium transport appearing in micro-scale combustion are discussed. New flame regimes and instabilities such as flame bifurcation, weak flames, flame cells/streets, thermal and kinetic quenching, flameless low temperature catalytic combustion, repetitive extinction and ignition, spinning flames, spiral and multi-branched flames, symmetric and asymmetric oscillating flames are discussed. Finally, an overview of future research and conclusion are made. The goal of this review is to present an overview of the development of micro-power generators by focusing more on the advance in fundamental understanding of micro-scale combustion. 相似文献
14.
15.
Coal is the most abundant energy source, and around 40% of the world's electricity is produced by coal combustion. The emission generated through it put a constraint on power production by coal combustion. There is a need to reduce the emissions generated through it to utilize the enormous energy of coal for power production. Detailed understanding of various aspects of coal combustion is required to reduce the emissions from coal‐fired furnaces. The aim of present paper is to review various aspects of pulverized coal combustion such as oxy‐fuel combustion, co‐combustion of coal and biomass, emissions from pulverized coal furnaces, ash formation and deposition, and carbon capture and sequestration (CCS) technologies to outline the progress made in these aspects. Both experimental and numerical aspects are included in this review. This review also discusses the thermodynamic aspects of the combustion process. Furthermore, the effect of various submodels such as devolatilization models, char combustion models, radiation models, and turbulent models on the process of pulverized coal combustion has been investigated in this paper. 相似文献
16.
17.
高温空气燃烧技术具有高效节能和低NOx排放等多重优越性,是一种新型燃烧技术。为了深入研究高温空气燃烧机理和低氮氧化物排放特性,将湍流N—S方程与扩散燃烧模型和热力型NO生成模型相结合,研究了低氧浓度条件下,燃烧参数,如燃气供应量,过量空气系数,进口空气预热温度以及进口空气氧含量对燃烧的影响,为发展高温空气燃烧技术提供了理论依据。 相似文献
18.
生物质燃料在燃煤锅炉上直接燃烧的试验研究 总被引:1,自引:0,他引:1
在1台燃煤锅炉上进行了生物质燃料燃烧试验和与燃煤的对比试验。结果显示,燃煤锅炉须经改造才能适应生物质燃料。生物质燃料与燃煤比较,不论燃料性质、燃烧现象、结焦特性、对炉膛的要求等方面都不同。生物质燃料燃烧时出现了不低于1 300℃高温区域和较高的NOx排放,与文献报道差别较大。 相似文献
19.
HCCI汽油发动机一般采用组合燃烧控制策略,根据发动机工况不同,HCCI汽油机分别采用SI燃烧模式、SI-HCCI燃烧模式和HCCI燃烧模式.在这种控制方式下,燃烧模式的辨识具有非常重要的作用与意义.笔者在装有全可变气门系统的汽油HCCI发动机上,测取HCCI发动机各工况下爆震传感器信号和瞬时转速信号,用时频分析方法从爆震传感器信号和瞬时转速信号中提取了特征量,分析了它们和HCCI汽油机燃烧模式之间的关系.通过辨识函数分析,基于爆震传感器信号特征量和瞬时转速信号特征量,建立了的HCCI燃烧模式辨识模型.分析表明,HCCI燃烧模式辨识模型能够较好地辨识出HCCI的燃烧模式,总体辨识成功率在75%左右. 相似文献