Experimental Study on an On—Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.     

LDA在燃气轮机燃烧室流场测量中的应用

介绍了激光多普勒测速技术在燃气轮机燃烧室内部流场测试的应用，阐述了LDA的基本原理和模型燃烧室内光学路径的实现方法，同时作者利用双相位多普勒分析仪DualPDA (Cual Phase Doppler Anemometer)对模型燃烧室内部流场进行了二维冷态测试，获得了大量的原始数据，为深入研究燃烧室内部气流特性提供了实验基础。     

计算机技术在流速仪法测流中的应用

流速仪法测流理论成熟,测试工艺完善,精度较高,测量容易控制,具有重复性好、成果非常可靠等优点,但同时存在着计算任务繁重的缺点,因此大大地限制了该方法在生产中的应用.本文介绍了如何运用现代计算机软、硬件技术改进流速仪法测流,使这种流量测量方法能更好地为生产、科研服务.     

Influence of mass air flow ratio on gas-particle flow characteristics of a swirl burner in a 29 MW pulverized coal boiler

In a gas/particle two-phase test facility, a three-component particle-dynamics anemometer was used to measure the characteristics of gas/particle two-phase flows in a 29 megawatt (MW) pulverized coal industrial boiler equipped with a new type of swirling pulverized coal burner. The distributions of three-dimensional gas/particle velocity, particle volume flux, and particle size distribution were measured under different working conditions. The mean axial velocity and the particle volume flux in the central region of the burner outlet were found to be negative. This indicated that a central recirculation zone was formed in the center of the burner. In the central recirculation zone, the absolute value of the mean axial velocity and the particle volume flux increased when the external secondary air volume increased. The size of the central reflux zone remained stable when the air volume ratio changed. Along the direction of the jet, the peak value formed by the tertiary air gradually moved toward the center of the burner. This tertiary air was mixed with the peak value formed by the air in the adiabatic combustion chamber after the cross-section of x/d = 0.7. Large particles were concentrated near the wall area, and the particle size in the recirculation zone was small.     

Particle image Velocimetry measurement of flow across tube bundle in waste heat boiler

IntroductionShell-and-tube heat exchanger is the key componentof waste boiler applied abundantly in industry. Becauseof the extfCme flow complexity, it is very difficult topredict the heat transfer and pressure drop characteristics.The vortex and flow stagnation will lead to thedeterioration of heat transfer, deposition of scale andcormsionll]. So the investigation of the characteristics offlow across the tube bundle in shell side is of practicalimportance. Moreovef, it is of theoretical impo…     

35t_h沸腾锅炉的动态数学模型及其数字仿真

本文通过机理分析建立了DG35/39—7型锅炉的分段集中参数数学模型,并在数字计算机上进行了仿真,将得到的主要阶跃响应曲线与现场相同型号沸腾锅炉的试验结果进行了比较和分析。表明所建模型是正确的。仿真结果可用于这种型号沸腾锅炉自动控制系统的设计及参数整定时参考。     

Development of optical digital interferometry technique for measurement of thermodiffusion coefficients

The paper presents the development of an experimental technique based on optical digital interferometry for measuring thermodiffusion (Soret) coefficients. The experiments are performed in a cubic cell containing an aqueous solution and being heated from above. This is the first report on the method that allows to record the temperature and concentration fields in the entire cell rather than just between two points. Such information is not only available at the steady state, but within the whole diffusion process. The time-dependent evolution of the concentration field allows the measurement of molecular diffusion coefficient in addition to the Soret coefficients. The measurements of transport coefficients have been performed in water/ethanol mixture and water/isopropanol mixtures.     

A cold model experimental study on the flow characteristics of bed material in a fluidized bed bottom ash cooler in a CFB boiler

IntroductionA fluidized bed bottom ash cooler is often used totreat high temperature bottom ash to reclaim heat andfine particles from the ash, and to have the ash easilytransported. Among the large CFB boilers in operation inthe world, there are many ash coolers that often workabnormally['-','].There are six fluidized bed bottom ash coolers in theimported 410im CFB boiler that was built and operatedin Gaoba power plant, Sichuan province, China in 1996N].High temperature slag-bond and jam …     

循环流化床锅炉运行节能技术的实践

总结了宁波光耀热电厂循环流化床锅炉生产运行中遇到的问题,对解决堵煤、点火及合理控制调整运行等一系列循环流化床锅炉运行中的常见问题进行了详细分析,经过探索和实践。提出优化运行和设备改造方案。通过实施有效的节能措施,提高了循环流化床的效率,达到了节能降耗的效果。     

Correlation of spherical thermistor for the measurement of low velocity air flow

A spherical thermistor, an accurate temperature sensor, is employed as an air velocity sensor in this work. The measuring principle is derived and the effects of the insulation layer, air temperature, natural convection and thermal radiation are discussed. Two different correlation relations for velocity measurements are proposed based on theoretical analyses and experimental calibrations. Experiments have shown that spherical thermistor is a good velocity sensor for speed between 0.1–2.5 m/s at room temperature and the insulation layer hardly influences the accuracy of the thermistor used in the present work. Modification on correlation can even further improve measurement accuracy. Since the thermistor is small and cheap, it is possible to apply this method to multi-point velocity measurement with a low disturbance to the flow field.     

SPC技术在柴油机排放测量中的应用

将SPC统计技术应用于实验室测量系统,介绍排放测量过程控制的具体步骤和方法,以期推动测量过程控制新技术的应用。     

多波长消光法粒径测量下限影响因素分析

介绍了根据Lambert-Beer定理并采用多波长消光法测量颗粒粒径分布的方法。提出了基于数值模拟和数理统计对多波长消光法粒径测量下限进行估计的方法。通过数值模拟分析讨论了入射光波长、颗粒相对折射率和透光率对粒径测量下限的影响。研究为多波长消光法粒径测量在实际应用中的可行性提供了指导。     

CAN总线技术在锅炉监测控制中的应用

CAN总线技术的特点,及其在锅炉运行监测控制中的实现原理,说明了CAN总线技术将在锅炉监控系统中得到广泛应用.     

Application of spectral technology in flame measurement

Spectral technology has become an important detection method due to its advantages such as nonintrusive measurement and on-line analysis. In this paper, two applications of spectral technology in thermal detection were proposed. First, a novel spectroscopic method based on Planck’s law for measurement of emissivity was introduced. The emissivity, obtained by comparing the radiation intensity of the blackbody which had the same temperature as the flame with the detected intensity of the flames, could be used for on-line measurements and had a relatively higher upper temperature limit. Then, a spectroscopic method for composition detection of blended fuels was proposed based on the emissivity measured. By comparing the spectra of blended fuels and single fuels, the ratio of single fuels of the blended fuel could be calculated. The measurement system proposed in this paper, which consists of a spectrometer and a computer, is very compact.     

电站锅炉SCR系统流场的冷态试验与数值模拟的研究

采用冷态试验和数值模拟相结合对某电厂660 MW燃煤锅炉SCR脱硝系统中整流格栅、多孔板、导流板的设计方案进行了速度场和浓度场分布及压降的研究。结果表明数值模拟结果和冷态试验结果较为吻合。其中AIG上游速度分布CV值为15.4%,催化剂入口速度分布CV值为8.1%,浓度场CV值为5.7%,满足系统设计要求。催化剂入口处安装整流格栅可以优化进入催化剂层的气流方向,使烟气垂直进入催化剂层。     

数字式调速系统在V280/285船用柴油机族的应用研究

通过对船用柴油机数字式调速系统进行配机调试,对该系统PID动态调节参数进行优化,以达到全面改善系统动、静态品质的目的。并通过台架性能试验和运用考核,对该系统性能作进一步验证考核。     

飞灰复燃对炉内颗粒沉积状况的影响分析

实际工程表明,采用飞灰复燃技术对锅炉进行改造,可以减少飞灰所带走的燃料损失,提高锅炉效率,但飞灰回收复燃给壁面颗粒沉积状况也带来了影响.采用FLUENT模拟了SZL15-1.25-AⅡ型双筒链条蒸汽锅炉炉内燃烧,对比分析了采用飞灰复燃技术前后炉内壁面颗粒沉积状况.模拟结果表明,飞灰复燃对锅炉顶墙、前墙及后墙的颗粒沉积速率影响较大,其中飞灰复燃提高了顶墙和前墙的颗粒沉积速率,降低了后墙颗粒沉积速率,而对锅炉前后拱的影响很小可以忽略.减小飞灰入射质量流量或调整飞灰入射角度为水平偏下,均可以降低颗粒在水冷壁的沉积速率,有利于炉膛与水冷壁间的传热.     

Visualization and Experiment of Tip Vortex Phenomenon in Cooling Fan using Digital Particle Image Velocimetry

The Digital Particle Image Velocimetry (DPIV) is an efficient method for measuring the internal flow field of a low-speed cooling fan. This paper studied the velocity field by means of PIV technology for a leading edge swept axial-flow fan without casing, and the tip vortex phenomenon was observed. Time-averaged velocity measurements were taken near the pressure surface, the suction surface and the tip of blade, etc. Moreover, the flow characteristics were visualized using numerical techniques. Experimental results showed that this tip vortex existed at the leading edge of the blade. The generating, developing and dissipating evolvement process of the tip vortex from the blade leading edge to downstream were discussed in detail. In addition, by comparing DPIV results and numerical results, a good agreement between them indicated a possibility to predict flow field using CFD tools. The experimental data provided in this paper are reliable for improving the aerodynamic characteristics of the open axial fan.     

基于GSM短信息的灌区明渠测流系统

基于GSM无线通讯网络技术,提出了一种采用液位传感器、单片机、西门子TC35芯片以及单晶硅太阳能电池等元件构成的灌区明渠流量测量系统方案.采集的数据 包括时间 通过GSM公众网络以SMS的方式上传至控制中心,再由控制中心实现用水计量、水量宏观调配、水费征集和报表打印功能,进而以较低的成本实现灌区测流管理的自动化和信息化.     

数字化检测技术在模具修复中的研究与应用

随着模具在制造业应用领域的发展,模具修复工作也显得极为重要.首先简要介绍了数字化检测技术的重要思想,进而详细阐述了数字化检测技术在模具修复中的检测方法和检测步骤,最后利用一实例验证了数字化检测技术在模具应用中的可行性.