玉米和豆粕混合粉尘最低着火温度实验研究

为了研究玉米粉尘和豆粕粉尘的着火性能以及分析其配比对混合粉尘最低着火温度和火焰强度的影响规律，利用最低着火温度测试仪测量粉尘最低着火温度，分析了粉尘质量、喷粉压力对不同粉尘最低着火温度和火焰强度的影响，以及玉米和豆粕混合粉尘最低着火温度的变化规律，结果表明：火焰强度普遍随粉尘质量的增大而提高，相同质量和压力下玉米粉尘与豆粕粉尘相比，前者火焰强度更高；玉米粉尘和豆粕粉尘的火焰强度均在20 kPa压力下最高，玉米粉尘和豆粕粉尘火焰强度最低时的压力分别为30 kPa和50 kPa;随着质量的增大，粉尘的最低着火温度均降低，相同质量的玉米粉尘最低着火温度比豆粕粉尘低20℃;质量对混合粉尘最低着火温度的影响大于配比。研究成果可为饲料行业粉尘设备的选择和易爆模型的设计提供参考。     

双基推进剂燃烧火焰温度CARS测定技术

得到了双基推进剂燃烧火焰CARS实验谱图及相应的温度拟合值。实测结果表明，燃烧火焰平衡区的CARS实验拟合温度数值与相应的热力学计算温度值基本吻合，连续采集的CARS谱显现的温度梯度说明CARS技术可以应用于推进剂燃烧火焰温度的实时诊断。     

换火周期与熔窑火焰温度波动

在熔窑换火周期内，随着格子体温度的降低，预热空气温度和火焰温度随之降低，通过分析李赫特式格子体蓄热室热交换，计算出格子体体积、换火周期与预热空气温度和火焰温度波动值之间的对应关系，结论指出，要使火焰温度稳定，除了格子体应有足够大的体积，还应该有恰当的换火周期。     

用照度计测定固体推进剂燃烧的火焰温度分布

本文介绍了用照度计测定固体推进剂燃烧火焰温度分布的原理、方法和装置。用标准温度灯验证了该测试系统。在常压、室温下测定了两种双基推进剂和一种复合推进剂的燃烧火焰温度分布。实验指出:双基推进剂的燃烧火焰温度分布符合稳态的燃烧模型,而复合推进剂燃烧的多次实验证明:在火焰相对长度20％和80％附近分别存在两个高温燃烧区;在火焰相对长度40％附近,存在着低温燃烧区。     

轴类零件弯曲变形的火焰矫正

本文叙述了火焰矫正技术的基本原理,火焰矫正时加热温度的确定原则和影响火焰矫正能力的主要因素。     

乳化燃油火焰温度测定的简易方法

为弥补一般光度法测乳化燃油火焰温度的不足,本文结合最新国外文献,设计了一种测定乳化燃油火焰温度的简易方法,以活塞式燃烧管为燃烧器,用细丝热电偶测火焰温度,利用小烟囱减少外界风及气流对火焰的影响,促使火焰正常燃烧。文中给出了试验装置图,并对此法的特点进行了比较和讨论     

SWX多路温度巡回检测扩设计与开发

本文介绍了为测量硫化机热板温度而开发，设计的ＳＷＸ多路温度巡回检测仪的原理，使用及其推广应用情况。     

延迟焦化炉的优化操作

采用 PM695 红外热像仪,针对延迟焦化装置的焦化炉进行了红外监测,通过测量炉管外壁温度,来判断其内壁结焦情况和炉膛温度场分布规律,及时进行烧焦(除焦)和调整火咀火焰大小,使炉膛温度分布均匀,降低炉膛高温区温度,达到控制炉管内壁结焦速度、延长焦化炉寿命;减少燃料消耗,提高加热效率.     

梯温炉法确定泡沫玻璃发泡温度的研究

本文用梯温炉法确定了泡沫玻璃的发泡温度。介绍了梯温炉的结构及原理，根据测量结果绘制了发泡温度与泡径的关系曲线。讨论了发泡温度对泡径的影响，并将测量结果和DTA曲线进行了比较。结果表明，梯温炉法与DTA曲线的实验结果吻合。应用梯温炉法确定泡沫玻璃的发泡温度。准确、直观、简捷，测量结果令人满意。     

底烧式玻璃熔窑燃烧器内外管进气配比的数值模拟优化研究

应用数值模拟对浮法玻璃熔窑底烧式喷枪的燃气配送比例进行了模拟优化研究,从火焰温度、高温区覆盖面积和CO浓度等对不同进气配比下的燃气燃烧效果进行了对比分析。研究表明:燃气喷枪外管流量较大有助于喷射火焰对玻璃液面的加热,提高火焰温度和覆盖面积,但外管燃气流量过大将导致燃气燃烧不充分、火焰温度下降。在大管压力2.9 k Pa小管压力0.55 k Pa的进气压力配比下,火焰温度较高,火焰覆盖区域较大。     

Inhibition effectiveness of dry chemical in methane/air flames

Inhibition effectiveness of dry chemical powders has been examined by detecting the temperature changes in the quenched flat-flame burner. A special particle delivery system was constructed to supply reliable particle concentration to a quenched flat flame. Particle evaporation phenomena in the flat flame environment was investigated by utilizing laser attenuation method which could determine the fraction of particle disappearance in the flame. The result from the flat flame inhibition experiments have clearly demonstrated that the ranking of effectiveness among KHCO₃, NaHCO₃, and NaCl reverses over the 1200–2000 K temperature range as flame suppressants. The results also showed that dry chemicals are effective inhibitor in the high temperature condition such as in the gaseous flame but not effective one in the coal flame of low temperature. It is concluded that, of all the experiment-specific flame properties, the maximum flame temperature at which the inhibitor evaluation is conducted, was a major parameter to determine the flame inhibition effectiveness in this work.     

基于改进BP神经网络陶瓷梭式窑火焰图像识别方法

在陶瓷产品生产过程中,不同烧制阶段陶瓷梭式窑烧结带温度发生相应的变化,其对应的火焰图像也随着变化。本文针对陶瓷梭式窑烧结带温度检测提出一种基于改进BP神经网络的火焰图像识别方法。首先对获取的火焰图像利用改进的小波阈值算法去除图像中的噪音进行预处理,其次基于改进的BP神经网络对得到的火焰图像三个分量值R、G、B和测得的火焰温度进行数据拟合,最后测试已训练的神经网络识别火焰图像的效果。实验结果表明,改进后的BP神经网络收敛速度更快、训练时间更短、误差更小,能够更好地检测陶瓷梭式窑火焰图像温度。     

Investigation of the effect of the flame holder geometry on the flame structure in non-premixed hydrogen-hydrocarbon composite fuel combustion

In this paper, the effect of the flame holder geometry on the flame structure of a mixed hydrogen-hydrocarbon fuel is numerically studied. The fuels used in this study are 100% H₂, 50% H₂ + 50% CH₄, and 100%CH₄. Numerical results obtained by using the k-? and β-PDF models show good agreement with experimental data. The results show that increasing both the flame holder length and hydrogen percentage in the fuel decreases the flame length. The flame temperature decreases with decreasing flame holder length. Adding hydrogen to methane increases the peak temperature of the flame and moves its location toward the burner inlet. It is observed that the dependence of the flame length as a function of the flame holder diameter has a minimum at a certain value of the latter. The flame temperature is higher for smaller flame lengths.     

稀薄燃气多孔介质燃烧二维火焰数值模拟

对稀薄低热值气体在多孔介质燃烧中的二维火焰温度分布进行了数值模拟。在一定工况参数下,考察了多孔介质二维火焰峰面和温度分布特性,以及火焰峰面传播过程。详细分析了当量比、燃气流速、及壁面热损失等工况参数对燃烧火焰和高温峰值的影响。结果表明,在火焰传播过程中,火焰峰面形状逐渐变化,导致高温区域分布逐渐改变;随着当量比增加,近壁面处的火焰峰面倾斜程度逐渐减少,火焰峰面逐渐向上游传播,火焰峰面形状由梯形分布逐渐转变成两侧向下倾斜的直线分布;燃气流速对火焰峰面形状和位置的影响与当量比相反;壁面热损失引起火焰峰面倾斜,对火焰位置影响较小。     

乙醇浓度和应变率对扩散火焰特性的数值分析

研究液体燃料乙醇对冲燃烧的火焰特性是理解扩散火焰形成和指导乙醇对冲燃烧器设计的关键。采用对冲扩散火焰模型,结合光学薄辐射模型,模拟空气与氮气稀释下乙醇形成的扩散火焰,探讨了乙醇浓度和应变率对扩散火焰的火焰结构、温度分布和温度峰值处的温度敏感性的影响规律。结果表明：随着乙醇浓度的增加,CO和H₂反应区域向燃料侧移动,火焰区域变宽,火焰温度峰值逐渐升高,升高趋势渐缓,中间产物和CO对温度敏感性的影响减弱;随着应变率的增加,自由基和CO增多,中间产物减少,组分的分布区域和火焰区域变窄,火焰温度峰值逐渐降低,中间产物和CO对温度敏感性的影响逐渐增强。     

Research of numerical simulation for HVAF thermal spraying process on rotational roll

HVAF thermal spraying has the characteristics of low spraying temperature, high coating density, and strong corrosion resistance. It is widely used in the aerospace, iron–steel metallurgy, national defense and military industry, petrochemical industry, and other fields for manufacturing protection and repair strengthening, which has achieved significant economic benefits. In this study, a numerical model of HVAF thermal spraying on a circular roll was established by the computational fluid dynamics method. The characteristics of the spraying flame, evolution of the gas composition mass fraction, and influence of the spraying parameters on particle flight behaviors were calculated and revealed. Based on the dynamic mesh method, the effect of roll speed on the spraying flame characteristics and particle flight behaviors was analyzed. Calculations show that the spraying flame is extruded at the Laval nozzle and the speed rapidly increases to 805 m/s, which increases to a supersonic speed through the barrel. The flame flow rises rapidly reaching the surface of the roll, which is 780 m/s. The highest temperature is in the combustion chamber, and the flame temperature of the airshed is a damped vibration. The flame covers the surface of the roll to preheat it, and the flame temperature there decreases layer by layer from the inside to outside. The particle diameter significantly effects the powder flight behavior. The flame velocity increases with the barrel length increasing. The flame temperature up to the peak when the barrel length is 190 mm. As the rotation speed of the roll increases, the temperature, velocity, and pressure of the flame flow on the roll surface change in a certain extent. The particle spatter will be increased with the rotational speed increasing of the roll, which little affects the particle temperature.     

阻燃剂表面改性对阻燃沥青性能的影响

为提高阻燃剂与沥青的相容性,对阻燃剂进行表面改性并用于制备阻燃沥青.通过沥青氧指数试验、软化点试验、动态剪切流变试验、延度试验和离析试验评价阻燃剂对沥青阻燃性能、高、低温性能及储存稳定性的影响并确定最佳掺量.借助热重(TG)和扫描电镜(SEM)分析阻燃剂的表面改性机理和阻燃机理.结果表明,阻燃剂可以显著提高沥青的阻燃性能和高温性能,当掺量不超过8%,对沥青的低温性能和储存稳定性影响较小;阻燃剂可以促进沥青成炭,减少沥青燃烧时气体挥发物的逸出;表面改性会提高阻燃剂的分散性和阻燃沥青的热稳定性,改善阻燃沥青的阻燃性能和低温性能.     

炼磷高炉单元模拟

本文是高炉炼磷过程模拟工作的一部分,它着重讨论了高炉单元模块的各种操作参数,如:热风温度、富氧度、喷吹天然气量、水蒸汽量、煤粉量、火焰温度等相互之间的关系以及它们变化时引起的过程变化,可代替许多局部试验,为高炉炼磷的扩大试验带来效益。     

基于光学分层层析成像原理的火焰测温法

燃烧火焰温度场的测量无论对研究火焰的结构及生成机理、燃料的混合和燃烧方式,还是对燃烧设备的稳定运行和控制都具有重要的意义。介绍了一种利用高速分层摄像控制系统重建火焰温度场的方法。连续的三维发光体可以看成若干个互相平行的二维发光断层的组合,对发光体某断层进行聚焦摄像,得到的图像是该断层的像和其他断层的离焦像的叠加像。对不同断层分别快速聚焦摄像,得到一组辐射图像,采用图像反演算法,可以重建各断层的原始图像。根据图像灰度和火焰温度之间的关系,可建立火焰的三维温度场。通过蜡烛火焰实验,验证了该方法的可行性。实验结果在一定程度上揭示了火焰内部的辐射分布、温度分布和燃烧结构,反映了火焰的三维燃烧特性。该方法可作为一种新的测量和诊断方法,应用于燃烧火焰三维场参数和其他两相流三维场参数的测量中。     

Flame structure of LPG-air Inverse Diffusion Flame in a backstep burner

The present experimental study characterizes the turbulent LPG Inverse Diffusion Flame (IDF) stabilized in a backstep burner in terms of visible flame length, dual flame structure, centerline temperature distribution, and oxygen concentration. The visible flame length for a fixed fuel jet velocity is found to reduce with increase in air jet velocity. Besides this, the effect of air and fuel jet velocities on visible flame length is interpreted using a new parameter, Global Momentum Ratio (GMR). Interestingly, GMR seems to be correlating well with the visible flame length for the air and fuel velocity ranges considered in the present study. Moreover, the dual flame structure of IDF is identified with the help of CH-chemiluminescence signature. The existence of dual flame structure of IDF is confirmed further with the centerline temperature and oxygen concentration measurements.