共查询到19条相似文献,搜索用时 218 毫秒
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气流床气化炉内火焰的辐射光谱包含着大量与火焰结构、火焰温度及当量比等有关特性的信息,因此对火焰进行有效的光谱诊断,是实现燃料高效利用、监控和优化气化过程的必要手段.基于实验室规模多喷嘴对置式气化实验平台,以柴油及水煤浆为原料,重点研究了气化炉内撞击火焰Na~*、K~*二维辐射分布特征,进而表征气化炉内火焰温度分布.结果表明,相比较两喷嘴火焰,四喷嘴火焰撞击区自由基辐射强度明显增大;Na~*的二维强度分布明显强于K~*的二维强度分布,且柴油中K含量高于Na,说明在相同条件下,Na比K更加容易被激发;随O/C摩尔比增大,Na~*及K~*辐射强度均增大,撞击区温度升高;在不同O/C摩尔比条件下,撞击中心辐射强度均最大且撞击中心火焰温度最高. 相似文献
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基于多喷嘴对置式水煤浆气化试验平台,利用高温内窥镜配合使用高速相机,结合火焰图像处理技术,研究了多喷嘴对置式气化炉内水煤浆撞击火焰高度及其脉动频率特征,选用的图像处理方法可实现撞击火焰高度区域图像的有效分割.结果表明,撞击火焰的平均火焰高度和最大火焰高度均随氧碳比的增大不断上升,且撞击火焰稳定性增强.撞击火焰特征频率随着氧碳比的升高而降低,主要频率特征峰的幅值降低,脉动特征频率在1~3Hz处趋于稳定.在水煤浆操作的典型氧碳比条件下,撞击火焰将不会直接冲蚀到拱顶耐火砖. 相似文献
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采用水冷取样管与气体净化分析系统,对气化炉内喷嘴平面的气体浓度分布进行了热态试验研究.通过图像处理将火焰图像沿气体取样管方向分为火焰撞击区、过渡区和无火焰区三部分.试验结果表明,气化炉内火焰撞击面气体组分与火焰形状密切相关,气体浓度在过渡区变化最大;CO2和O2浓度的最高点出现在炉膛中心位置,在无火焰区,所测气体浓度基本保持不变;CO与CO2收率的比值可作为火焰形状判断的依据;或当O2浓度降到小于O.03%时也可以认为火焰结束. 相似文献
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提出了一种热电偶扫描快速测量炭烟火焰温度场的方法,并对McKenna燃烧器形成的乙烯/空气平面炭烟火焰温度场进行测量.结果表明:在1450~1700 K火焰温度时,由炭烟沉积导致热电偶热辐射损失的修正温度偏差为200~240 K,修正后的火焰温度测量值与其他测温方法结果吻合良好,证实了该方法可以快速测量炭烟火焰温度场;... 相似文献
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双燃料燃气轮机喷嘴结构设计与数值模拟 总被引:1,自引:0,他引:1
针对化学回热循环燃气轮机燃烧室,设计了几种双燃料喷嘴的气体燃料流道结构,应用RNG(重整化群)k-ε双方程湍流模型、PDF燃烧模型以及SIMPLE算法,借助CFD技术对采用这几种不同喷嘴结构的燃烧室燃烧流场进行了数值模拟与对比分析。通过对这几种喷嘴结构模型的火焰长度、高温区的位置、壁面温度、出口温度场的均匀性等关键影响因素的对比分析表明:采用斜气孔气体燃料旋流双燃料喷嘴,可以在气体流道中产生预旋气流,使裂解气与空气能更好地进行掺混燃烧,同时避免了火焰烧到喷嘴和火焰筒壁面,出口温度场也更均匀。 相似文献
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用双色法研究汽油机燃烧火焰的温度分布 总被引:2,自引:0,他引:2
探讨了用双色法测量汽油机温度场的可行性.通过添加氧化铝粒子替代柴油机燃烧产生的碳烟颗粒,利用高速彩色CCD拍摄得到图像,采用双色法计算缸内温度分布.为验证其可行性,在稳态火焰燃烧器上同时采用双色法和热电偶对甲烷空气火焰进行温度测试对比,并讨论不同双色组合对测试精度的影响.结果表明用氧化铝粒子和RB模式的双色法可以获得较好的精度.在一台汽油进气道喷射可视化发动机上,通过向进气道喷射混合均匀的纳米氧化铝粒子,对缸内燃烧过程进行分析,获得了汽油机温度场信息. 相似文献
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Zhihong LI Shi LIU Huaiping MU Fan JIANG Jianmin GUO Institute of Engineering Thermophysics Chinese Academy of Sciences P.O. Box Beijing P.R. China. 《热科学学报(英文版)》2004,13(4):371-375
This paper presents a study on a novel instrumentation system for the measurement of temperature distribution of combustion flames. This system operates upon the three-color principle combining advanced optical sensing and digital image processing techniques. It comprises an endoscope, a light splitter assembly, a CCD camera, a frame-grabber and associated software. This system was calibrated using a blackbody furnace as standard temperature source. The relationship between flame temperatures and grey-level of the images was established through image processing and function correlation. Experimental results obtained on a gas-fired combustion rig provide flame images and temperature distributions on three different wavelengths. Based on the flame temperature distribution the combustion conditions can be analyzed. Experimental results also reveal that this system is capable of online measurement of temperature distribution in a combustion zone. This system can potentially be applied to many areas such as power generation, metallurgy, chemical engineering. It is also a powerful tool for improving the control of combustion process. 相似文献
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在一台视窗上置式柴油机可视化实验装置上用高速摄像机记录下缸内燃烧过程的火焰照片,应用三基色法计算了缸内燃烧温度场.结果表明,用三基色法分析的缸内温度场分布与实际情况相一致;结合示功图曲线对柴油机着火和燃烧过程进行了分析,得到的结果符合柴油机实际着火和燃烧过程的发展规律.燃油在高温缺氧情况下会发生裂解形成较高温度的较大碳粒,影响相应零部件的使用寿命和发动机性能. 相似文献
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炉膛燃烧温度场三维可视化监测方法模拟研究 总被引:23,自引:2,他引:23
为了利用火焰图像监测装置检测到的炉膛燃烧辐射能分布图像信息重建三维燃烧温度场,作者提出了一种针孔成像条件下的快速方法计算CCD(Charge-Coupled Device,电荷耦合器件)靶面接收的辐射能。成像像素接收到的系统网格单元的辐射能的份额的计算结果和辐射能图像计算结果均体现了成像过程的方向选择性和辐射能传递规律的作用。针对炉膛燃烧三维温度场重建的严重病态问题建立了一种基于Tikhonov正则化的求解方法,对于单峰型三维温度分布重建模拟计算结果表明,即使辐射图像检测包含均方差达到0.11的误差,温度场重建误差仍能维持与测量误差基本相当的水平,温度分布可视化质量较高,各种图像检测组合方式的重建结果比较显示,炉膛四角沿高度方向每隔5m左右交叉对角布置两个辐射图像采集装置,能够获得较好的全炉膛温度场可视化结果。 相似文献
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Coal char particle size in the gasifier has an influence on the carbon conversion, gasifier slagging as well as the particle matter content in raw syngas. The particle size distribution in a bench-scale opposed multi-burner (OMB) gasifier illustrated that the secondary fragmentation behavior exists in the entrained-flow gasifier after the particles moving from high temperature impinging flame region to the gasification chamber outlet region. Particles larger than 200 μm in the impinging flame region have porosity structures with fragile shapes. Particle size distributions under different oxygen to carbon ratios (O/C) also indicate that there is an obvious fragmentation while the particle size is larger than 200 μm. As long as the coal char particles move from the impinging flame region towards the gasification chamber outlet region, the secondary fragmentation is probably taken place as a result of percolative fragmentation, undergoing gasification reactions and thermal stress. However, thermal stress fragmentation only has an influence on the particle sizes larger than 350 μm according to the calculation by a simplified mathematical model. 相似文献
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《Energy》2005,30(2-4):485-495
To study characteristics of heated material surface over 600 K, non-contact measurements of two-dimensional (2D) distributions of temperature and emissivity are very useful for process monitoring in engineerings, because of remote sensing in a short time. The 2D temperature distributions enable us to monitor the surface temperature quantitatively with high spatial resolution. The 2D emissivity distributions give us a capability to judge thermal degradations or defects of the surface. The 2D distributions of temperature and emissivity determined by two-color method using a CCD camera and two optical filters have been already reported by many authors. In this study, a four-color method is proposed to improve accuracy and precision of the temperature and emissivity. Four optical filters with narrow bandpass of 10 nm were used for our measurements, because the thermometry using narrow band is advantageous over that using wide one in terms of accuracy of temperature determination. Distributions of temperature and emissivity were also determined by two-color method for comparison. The results obtained by the four-color method have higher accuracy and precision than two-color method and we can recognize that several conditions of the material surface are clearly illustrated by the resultant 2D emissivity distribution. 相似文献
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Monitoring and control of combustion flames in utility boilers are required in order to optimize combustion conditions. This
paper presents an instrumentation system for the concurrent measurement of the temperature distribution and soot concentration
of flames developed on the two-color principle. This system consists of an endoscope, an optical assembly with optical filters,
a CCD camera, a frame grabber and associated image processing software. Experiments are performed on a methane-air combustor
and the temperature fields and the soot concentrations corresponding to the flame images are obtained. The results have demonstrated
that the system is capable of performing on-line measurement of flame and temperature distribution, providing temporal and
spatial characterization of the combustion process. In addition, the combination of advanced optical sensing and digital image
processing technique can help to define the threshold by the analysis of the background noise. Furthermore, the utilization
of the filter technique can enhance the image presentation effect to an extent. 相似文献