共查询到20条相似文献，搜索用时 15 毫秒
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WEN Liang-ying OU Yang-qi BAI Chen-guang WANG Hua 《重庆大学学报(英文版)》2005,4(4):195-198
1 Introduction 1 For pulverized coal injected into a blast furnace, the space from the outlet of the coal gun to the center of the raceway is the key district for the coal’s burning and also for works to probe hearth state. Remarkable achievements have been made in research on numerical simulation of combustion processes [1], but further advances are hindered owing to the limits of the means to examine three-dimension parameter distribution in the furnace. Temperature is the most basic parame… 相似文献
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The flame structure of gasoline engine is complicated and has the characteristic of fractal geometry. A fractal combustion model was used to simulate the engine working cycle. Based on this model, the fractal dimension and laminar flame surface area of turbulent premixed flames were studied under different working conditions. The experimental system mainly includes an optical engine and a set of photography equipment used to shoot the images of turbulent flame of spark-ignition engine. The difference box-counting method was used to process 2D combustion images. In contrast to the experimental results, the computational results show that the fractal combustion model is an effective method of simulating the engine combustion process. The study provides a better understanding for flame structure and its propagation. 相似文献
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The combustion behavior of two single coals and three coal blends in a 300 kW coal-fired furnace under variable operating conditions was monitored by a flame monitoring system based on image processing and spectral analysis. A similarity coefficient was defined to analyze the similarity of combustion behavior between two different coal types. A total of 20 flame features, extracted by the flame monitoring system, were ranked by weights of their importance estimated using ReliefF, a feature selection algorithm. The mean of the infrared signal was found to have by far the highest importance weight among the flame features. Support vector machine (SVM) was used to identify the coal types. The number of flame features used to build the SVM model was reduced from 20 to 12 by combining the methods of ReliefF and SVM, and computational precision was guaranteed simultaneously. A threshold was found for the relationship between the error rate and similarity coefficient, which were positively correlated. The success rate decreased with increasing similarity coefficient. The results obtained demonstrate that the system can achieve the online identification of coal blends in industry. 相似文献
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针对燃烧学课程理论教学中存在概念难理解、现象直观性差和缺少前沿科学等问题,在实验教学中开展了虚实结合的教学模式。开设了层流预混火焰、射流扩散火焰及水煤浆滴的实物实验;利用当前科研成果,开发了采用旋流、直流和W火焰煤粉燃烧技术的火电站锅炉的虚拟仿真试验。在经济、环保和有限的学时内,保证实验内容的全面性和系统性,促进能源动力专业实验与学科科学研究的深度融合,使学生接触学科前沿科学问题。教学实践证明,采用虚实结合的教学模式后,学生的专业兴趣和创新意识明显提高。 相似文献
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This paper presents a novel method of identifying coal type based on mechanistic methods. The ratio of the resonance line spectrum of a luminous flame and the continuous spectrum at the same wavelength eliminates the influence of temperature on spectral intensity. The atomic line spectra of Na and K are typical and significant over continuous flame spectra. The concentrations of elemental Na and K in the flame are exclusively relative to coal type and composition. Using an experimental furnace and charge-coupled device (CCD) optical spectrometer apparatus, the continuous spectra and atomic line spectra of Na and K elements were sampled from coal flames in real time. An empirical fitting method was used to simplify the formulas of absorption strength and flame temperature calculation, and rational solutions were obtained by using an iterative algorithm. Due to the change in reaction rate and absorption by soot particles, the relative contents of Na and K in a flame vary with the temperature and absorption strength. Arrhenius’s equation for temperature compensation was adopted. Compensation for soot density in the furnace was also satisfied by an exponential expression. At any one sampling position, the compensation parameters were identical for all coal types. After compensation for temperature and density of soot particles, the relative strength of the Na and K signals and the ratio between them uniquely matched the coal type burnt in various conditions. The results were replicated and verified in various conditions, and the response time of the system was of the order of seconds. 相似文献
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吴鸣 《武汉工程职业技术学院学报》2014,(4):71-74
运用基于数据挖掘的决策树分类算法,分析加热炉的大量生产数据,从中获取有价值的规则,形成规则知识库。最后从规则知识库中获取加热炉最优炉温设定值的方法。该方法可实现加热炉最优炉温设定值曲线的寻优及设定,可对应于不同的钢坯种类,提供控制系统优化控制指导,改善钢坯在加热炉内的燃烧过程,提高加热质量,降低加热炉能耗。 相似文献
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任瑞忠 《辽宁科技学院学报》2014,(3):6-7
北营新1号高炉通过优化高炉煤气处理流程,配置旋切顶燃式热风炉,采用前置预热炉、热管换热器分别预热助燃空气和煤气,使用带横梁的炉箅子技术、管道保温技术以及优化烧炉技术等,为送风温度达到1250℃创造了条件。高炉在精料基础上,通过控制合理炉腹煤气量指数和理论燃烧温度,优化煤气流分布,规范高炉操作等措施,2013年全年平均风温1248℃,达到国内同型高炉领先水平。 相似文献
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Jun-chun ZHANG Le-ming CHENG Cheng-hang ZHENG Zhong-yang LUO Ming-jiang NI 《浙江大学学报(A卷英文版)》2013,14(9):671-678
In this study, a porous inserted regenerative thermal oxidizer （PRTO） system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NOr emissions and high radiant efficiency. Zirconium dioxide （ZrOz） ce- ramic foams were placed into the combustion zone of a regenerative thermal oxidizer （RTO）. Different performance characteris- tics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NOx and CO emission levels within 0.002%~）.003% and 0.001%q3.002%, respectively. 相似文献
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樊荣 《宁夏师范学院学报》2008,29(3):19-24
近年来的一种新型光电子光谱仪被用来分析钠的多光子电离的光电子能量和空间分布.本文基于光电子成像光谱仪的基本原理,分析电子发射的动力学过程.以钠原子为例,利用共振多光子电离的方法研究并分析了电子初始角分布以及投影到探测器上的图像.结果表明,不同的初始条件(静电场能量和电子发射的初始动能之比),影响所获得的角分布以及探测图样. 相似文献
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针对现场固定空燃比燃烧导致无法根据波动燃气热值匹配最佳助燃空气,使热风炉热损失增加;残氧检测仪直接检测热风炉烟道残氧量,将导致氧化锆损耗快、高炉煤气费用计量单一等问题。针对以上问题设计一种残氧燃气分析系统,该系统并行于热风炉控制系统的前馈控制,将少量高炉煤气、空气先通入该系统进行燃烧并调整自身空燃比,得到最佳空燃比作用于热风炉控制系统并对并行系统残氧含量、高炉煤气热值进行数值模拟和相关性分析。通过改进PSO算法优化RBF神经网络预测方法对稳定运行系统建立模型,预测煤气热值作为优化热风炉空燃比,评价煤气质量、费用计量的有效参考条件。经实验仿真测试,该系统可有效提高空燃比修正精度,延长氧化锆使用寿命,减少热风炉热损失。 相似文献
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模拟了一种常规快速式燃气热水器的燃烧系统,研究了不同压力状况下的燃烧工况.得到的数值模拟结果与实验获得的数据吻合得较好,证明了所用物理模型和数学模型的合理性.结果显示,火焰高度和过剩空气系数依赖于系统出口和入口的静压差,而与燃烧室内的绝对压力无关.该静压差和系统中用于燃烧的空气量显著影响CO的生成,与CO的生成量呈反比关系,并同时影响燃烧区域内的温度场和速度场.为降低CO排放水平,必须增加进入燃烧系统的空气量,因此需要增加风机输出功率以提供足够的空气压头.该研究为设计快速式燃气热水器提供了一种行之有效的方法. 相似文献
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Temperature is the most important parameter for the improvement of combustion efficiency and the control of pollutants. In order to obtain accurate flame temperatures in a rotary kiln incinerator using non-intrusive thermographic method, the effective flame emissivity was studied. A combined narrow- and wide-band model and Mie scattering method were used to calculate the radiative properties for gases and fly-ash particles under different combustion conditions. The effects of the air/waste ratio and fly-ash particles on the effective flame emissivity were discussed. The results of numerical calculations showed that the effective emissivity decreased from 0.90 to 0.80 when the air/waste ratio increased from 1.0 to 1.8, and the effect of the fly-ash particles was ignorable under the conditions discussed in this paper. Experimental measurement results indicated that the accuracy of the thermographic temperature measurements improved significantly if the setting of the flame emissivity was adjusted according to the air/waste ratio. 相似文献
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基于数学形态学的锅炉火焰图像骨架提取 总被引：2，自引：0，他引：2
本基于二值数学形态学，建立了数字图像骨架提取方法，并给出了相应的算法．同时，对结构元素序列进行了研究，结构元素序列的选取是骨架提取的关键．最后，应用数字图像骨架提取算法，对锅炉火焰图像进行了处理．处理结果表明，所提取的骨架能够准确地描述火焰图像的几何形状． 相似文献
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许春磊 《临沂师范学院学报》2010,32(3):129-133
在总结传统粒子系统理论的基础上,提出了一种基于粒子系统的尾焰实时模拟方法．该方法在渲染过程中使用透明混合技术和billboard技术,并利用GPU的并行处理能力和高速运算能力,在GPU中实现billboard视向变换和透明混合．最后基于DirectX平台,利用VC＋＋进行编程实现了本文提出的尾焰模拟方法．模拟结果表明,此仿真方法具有很高的逼真度和实时性． 相似文献
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为了研究甲烷掺氢后的燃烧特性,采用定容燃烧弹实验系统和OpenFOAM软件,将实验测试与数值模拟相结合,系统地分析了掺氢比、指前因子、活化能等参数对甲烷燃烧特性参数的影响。研究结果表明,掺氢后可使混合气燃烧速度加快,燃烧温度提高;指前因子对燃烧性能参数影响不明显;活化能增加,导致燃烧反应速率对混合气初始温度变化的敏感性提高。 相似文献
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INTRODUCTION Magnetic Resonance Electrical Impedance To-mography (MREIT) is a new imaging techniquecombining traditional Electrical Impedance Tomo-graphy (EIT) and Current Density Imaging (CDI) fordetermining conductivity distribution inside a subject(Khang et al., 2002; Kwon et al., 2002). In MREIT, acurrent is injected into the subject through a pair ofsurface electrodes. The induced magnetic flux densityinside the subject can be measured through a Mag-netic Resonance … 相似文献
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Jun-yi LIANG Jian-long ZHANG Xi ZHANG Shi-fei YUAN Cheng-liang YIN 《浙江大学学报(A卷英文版)》2013,14(8):535-553
To solve the low power density issue of hybrid electric vehicular batteries, a combination of batteries and ultra- capacitors （UCs） could be a solution. The high power density feature of UCs can improve the performance of battery/UC hybrid energy storage systems （HESSs）. This paper presents a parallel hybrid electric vehicle （HEV） equipped with an internal combus- tion engine and an HESS. An advanced energy management strategy （EMS）, mainly based on fuzzy logic, is proposed to improve the fuel economy of the HEV and the endurance of the HESS. The EMS is capable of determining the ideal distribution of output power among the internal combustion engine, battery, and UC according to the propelling power or regenerative braking power of the vehicle. To validate the effectiveness of the EMS, numerical simulation and experimental validations are carried out. The results indicate that EMS can effectively control the power sources to work within their respective efficient areas. The battery load can be mitigated and prolonged battery life can be expected. The electrical energy consumption in the HESS is reduced by 3.91% compared with that in the battery only system. Fuel consumption of the HEV is reduced by 24.3% compared with that of the same class conventional vehicles under Economic Commission of Europe driving cycle. 相似文献