共查询到20条相似文献,搜索用时 453 毫秒
1.
2.
针对大型循环流化床(CFB)锅炉应用天然气点火系统存在燃烧不稳定火焰脱火的问题,以某电厂350 MW超临界循环流化床机组天然气点火系统为研究对象,探讨了天然气层流扩散和紊流扩散燃烧的机理,从燃烧学理论出发研究了天然气火焰脱火的主要原因是燃烧器喷口燃气流速与火焰传播速度不匹配。基于一元定常可压缩气体流动的基本特性,将天然气燃烧器气枪喷口简化为一元流体的喷管,计算出CFB锅炉天然气点火系统燃烧器出口的最大流速,以此为基础提出天然气系统燃气压力的调整措施和燃烧器喷口结构的优化方案。通过理论分析计算和设备的结构优化,解决了大型CFB锅炉天然气点火系统燃烧器火焰脱火的问题,可为同类型的机组提供借鉴的依据。 相似文献
3.
4.
5.
本文结合某项目SOFA燃烧器喷口管屏的生产装配制造难点进行简要分析,着重介绍了SOFA燃烧器喷口管屏装配校正胎架的设计过程,并对其应用进行了简单介绍. 相似文献
6.
三井巴布科克公司的W火焰锅炉技术,受锅炉结构及风箱位置等因素的制约,使得内直流外旋流的燃尽风喷口不能设置单独的调节装置调节旋流强度,故对燃尽风喷口的结构设计提出更高的要求。利用冷态模化试验和CFD数值模拟软件获得燃尽风喷口的阻力特性和流动特性。使燃尽风与锅炉的热工过程相匹配,实现封闭主流烟气,保证燃烧效率的作用。应用结果表明:当叶片与轴线的夹角为25°-30°时,燃尽风喷口出口射流的旋转动量矩衰减较慢,旋转动能可有效传递至炉膛中心,使得此处的可燃物质与空气充分混合,保证燃尽度。 相似文献
7.
8.
双矩形喷口平行射流的近场结构 总被引:1,自引:0,他引:1
为了研制水平浓缩煤粉燃烧器,对双矩形喷口自由射流的近场结构进行了试验研究,得到了燃烧器出口的冷态流场结构。本文阐述了雷诺数,喷口出口速度分布,喷口截面高宽比,两射流动量比和喷口间距离等因素对流场结构的影响。 相似文献
9.
W型火焰锅炉燃烧问题的分析和解决方法 总被引:5,自引:0,他引:5
W型火焰锅炉是我国大型电站锅炉燃用低挥发份燃料的主要燃烧方式之一。目前,我国运行的W型火焰电站锅炉中普遍存在着炉膛温度控制过高、炉膛结渣或结渣倾向严重、NOx排放过高、过热器超温或汽温偏差、燃用无烟煤燃烧效率不高和某些情况下燃烧不稳定等问题。该文在总结这些问题的基础上,深入分析了问题的根源。分析表明:出现上述问题的根本原因是缺乏一种着火稳燃性能好的适用于燃烧无烟煤、半无烟煤的低NOx燃烧器。对这些问题的解决方法进行了探讨,并以清华大学开发的富集型燃烧器为例,讨论了用优良稳燃型直流燃烧器改善W型火焰锅炉燃烧情况的可行性。图3表2参16 相似文献
10.
11.
Three dimensional numerical simulation of bituminous coal reburning in a full-scale tangentially fired boiler was conducted with CFD method to study the effects of reburn zone length, the height of reburn nozzles, the stoichiometric ratio in reburn zone, the reburn fuel fraction and the reburn coal fineness on NOx reduction efficiency and unburned carbon in fly ash. The results indicate that the NOx reduction efficiency reaches the largest value when the relative height of reburn nozzles is about 0.21 and the stoichiometric ratio is between 0.8 and 0.9 in reburn zone; NOx reduction efficiency increases with reburn zone length, reburn fuel fraction and the decrease of reburn coal particle size; the smaller the coal particle size is, the better the burnout performance of coal is. 相似文献
12.
研究表明,煤粉气流着火存在最佳煤粉浓度,在最佳浓度时火焰传播速度和温度可达到最大值,试验得知难燃煤粉气流从喷嘴出口的最佳风、粉重量比接近1.0时着火、燃烧稳定。将一次风粉混合物通过喷嘴前的分离器,分离成超浓和稀淡两股,分别送入炉膛四角内外并列下倾布置的对应喷嘴,形成炉膛中央的浓粉区,近墙四周为富氧淡粉的“风包粉”气流,构成下射“W”形新的切圆旋转燃烧,利于难燃煤及早着火、稳定燃烧、充分燃烬。文中简要介绍燃烧器设计和调控要点 相似文献
13.
Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes.It belongs to class of altitude compensating nozzles.A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability,where most missions have the greatest need for thrust.Aerospike nozzles are better suited to Single Stage to Orbit (SSTO) missions compared to conventional nozzles.In the current study,the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique.Steady state analysis with implicit formulation is carded out.Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model.The results are compared with experimental results from previous work.The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle. 相似文献
14.
为了优化一种用于携带流反应器系统的煤粉燃烧器结构参数,降低氮氧化物排放,本文利用计算流体动力学软件FLUENT对该煤粉燃烧器结构参数的优化过程进行了数值模拟研究,并与试验结果进行了对比验证。结果表明,燃烧器一次风喷口采用扩口结构以及对冲二次风的引入均能有效的促进二次风与一次风煤粉的混合,增强煤粉着火及燃烧的稳定性。适当增加二次风喷口与一次风喷口的间距可以加速煤粉的燃尽。采用优化后的结构参数可以获得更低的氮氧化物排放,为基于携带流反应器系统的燃煤污染物减排研究提供了坚实的基础。 相似文献
15.
16.
燃油锅炉油喷嘴雾化效果分析与改进措施 总被引:1,自引:0,他引:1
文章针对燃油锅炉油喷嘴雾化效果差、油枪滴油和油枪及炉膛受热面结焦、喷嘴破口、油枪需要频繁拆卸清洗等运行故障,分析了燃油锅炉油喷嘴的雾化效果和影响参数,提出了改进油喷嘴运行状况的一些措施,使燃油锅炉的运行质量和效率都得到了提高。 相似文献
17.
18.
19.
20.
Chengwen Sun Hongtao Zheng Ningbo Zhao Zhiming Li Wanli Zhu 《International Journal of Hydrogen Energy》2021,46(35):18644-18660
Outlet nozzles for a rotating detonation combustor were designed to meet a downstream turbine and reduce the high pressure and heat load caused by the oblique shock wave at the outlet. The effects of the rotating detonation combustor with two types of outlet nozzles were studied, and the performance and outlet parameters of the combustor were measured at an elevated chamber pressure and preheating temperature based on gas turbine conditions. The results showed that the outlet nozzles could cause changes in the wave collisions and folding of the weak flame front in the detonation formation process, but the basic propagation process was similar to that without a nozzle. The pressure ratio changed from 1.427 in the original model to 1.392 and 1.304 with the two types of outlet nozzles. Meanwhile, the outlet load was greatly improved. The peak values of the static temperature at the outlet dropped by 22.423% and 27.572% with the two types of outlet nozzles compared to the original model. In addition, the peak static pressures dropped by 75.737% and 83.722%, respectively. In addition, the outlet nozzles significantly reduced the unevenness of the outlet static temperature and static pressure distributions. This created a better outlet operating environment, thereby improving the performance of the rotating detonation combustor. 相似文献