利用火焰图像重建三维温度场的模型和实验

火焰温度场的非接触测量对于能源领域的生产和控制具有重要意义，根据摄像机光学成像模型和辐射传递原理，提出了根据火焰图像重建火焰三维温度场的模型和方法．采用代数重建技术ART对温度场控制方程进行求解，在煤粉试验炉上进行了三维温度场测试，测试结果为进一步研究温度场重建奠定了基础。     

炉膛中二维温度场与辐射参数的同时重建

辐射逆问题研究受到了广泛的关注。以炉膛为研究对象,开展了二维温度场与辐射参数同时重建的研究。用CCD接收边界辐射强度图像和辐射温度图像,提出用正则化方法从辐射温度图像中重建介质温度场,从辐射强度图像中更新辐射参数,两者交替迭代,直到收敛。模拟计算表明,在测量数据中加入标准方差为0.02,0.05的正态分布的误差后,仍可以较好地重建出介质温度场与辐射参数。图4表4参13     

非轴对称层流自由火焰温度场的辐射反演

将CT技术中的ART(代数重建)算法应用于火焰的反演，提出了一种基于发射-透射辐射测量的反演非对称层流自由火焰温度场的新方法。模拟算例表明：即使存在辐射量的测量误差，用ART算法反演非轴对称火焰的温度场亦可得到较为精确的结果。     

发射CT法同时测量含烟黑火焰的温度与烟黑浓度分布的实验研究

基于烟黑辐射特性，利用烟黑单色辐射强度图像信息，采用CT算法同时重建含烟黑火焰温度与烟黑浓度分布，对蜡烛火焰与煤油火焰的温度与烟黑体积分数进行了测量．测量结果表明在两种火焰中，较大烟黑浓度都位于较高火焰温度之内，即在火焰外环的反应区内．另外，由于煤油火焰的燃料量大，因而会增大火焰中的烟黑浓度，辐射损失增大，降低火焰温度．这与有关实验结论是一致的．     

紫外线知识讲座--紫外线的测量及其标准

1 关于紫外辐射的测量仪器 由于紫外辐射中散射量值几乎占到了总量的近一半，所以在紫外辐射的测量中，均以测量其总辐射(即直接辐射 散射辐射)作为主要目标。太阳紫外线的测量与太阳辐射测量一样，区分为分光辐射测量与总量测量。在分光辐射测量中，根据所用的手段又可分为利用窄带滤光片的固定波长测量与     

利用火焰图像同时重建温度场和浓度场的试验研究

煤粉火焰图像是火焰辐射经过发射、衰减和散射等过程后到达摄像机靶面的投影。火焰发射出的辐射强度与火焰自身的温度密切相关，而辐射强度的衰减则取决于弥散介质的特性和浓度。该文首先研究了辐射衰减系数与粒子浓度场的关系，提出了对温度场和浓度场进行同时重建的控制方程。最后，在小型燥粉炉上进行断面温度场和浓度场的重建试验。图ll参l2     

W型火焰锅炉炉膛温度场的可视化试验研究

使用火焰辐射图像探测系统探测炉膛空间发射到镜头各像素的辐射能量，然后从能量传递和平衡的角度，由所得图像重建空间的温度场。在300MW机组W型火焰炉进行了炉膛二维断面温度场可视化重建试验。试验在炉膛壁面布置4个CCD火焰探测器，采用计算机图像采集处理技术获取炉膛火焰辐射图像，通过对火焰辐射图像的处理以厦相关算法，重建炉膛断面温度分布、可动态反映火焰断面温度水平、火焰中心的偏穆和火焰刷墙等燃烧异常工况。断面温度场可视化结果刷新一次的时间不超过5S，满足在线监测的要求。     

对称与非对称碳氢火焰温度场重建实验研究

为了测量碳氢火焰的截面温度场分布,根据火焰烟黑辐射传递特性,提出了基于火焰发射辐射能图像的温度场重建模型,使用最小二乘QR矩阵分解法（LSQR法）求解该模型。数值模拟重建了轴对称和非对称分布的两类温度场,重建结果精度较高。进而对实验室的甲烷扩散火焰截面二维温度场进行了重建,结果与已有文献相比符合较好,特别是对非对称火焰,能准确还原其温度场分布特征,实验得到了较好的结果。     

乘用车柴油机噪声源识别方法的试验研究

以乘用车柴油机为研究对象，通过振动速度测量技术和声强测量技术相结合的方法对该发动机进行了表面辐射噪声源识别的研究。首先在半消声室内测量了发动机的声功率，然后测量了发动机各主要噪声辐射部件振动速度并分析了各部件的振动特性，并通过其表面振动速度计算了它们各自的声功率以及对总噪声的贡献，对不适于振动测量的旋转部件采用声强法测量了其声功率，最终得到了各主要噪声源的大小排列，并且分析了这些部件的噪声辐射特性。     

基于可见光-近红外多光谱图像的火焰场参数重建

提出一种新的同时测量火焰温度场、颗粒浓度场和气体浓度场的非接触光学测量技术.在稳态火焰周围安装4台电荷耦合器件(CCD),火焰的多光谱图像是由在CCD前安装的滤波片拍摄得到,使用的滤波片通过波长分别为0.436,μm(蓝光)、0.700,μm(红光)和1.87,μm(水吸收峰).建立了一个在三波长下的辐射反问题模型.通过水对波长的选择吸收性分离出颗粒吸收系数和水的吸收系数.利用统计窄带模型得到水浓度,利用Mie散射理论得到颗粒浓度.模拟两个算例,得到从水浓度场、颗粒浓度场到温度场重建误差依次减小.当颗粒体积分数低于1×10-6时,水浓度场可以准确重建出来.如果要精确测量水浓度,则需要辐射路径测量误差不大于1%,.     

电网企业数据中心能效测量与计算方法研究

  [目的]  在国内,电网企业数据中心的能耗正日益提高。为有效地计算出数据中心的整体能源效率状况,提出了一种可行的电网企业数据中心能效测量标准与计算方法。  [方法]  通过研究国内外数据中心能效的测评方法,针对电网企业数据中心多与办公楼公用部分基础设施的特点,提出了准确计算IT负载、优化机柜配电单元耗电量估算、优化冷却水系统耗电量估算等3种优化方法,给出了优化的能效测量计算方法。  [结果]  研究成果表明:应用该方法,可将非数据中心区域消耗的能源在计算中分离出来,比常规的计算方法更准确,更贴近于国际通用的数据中心能效定义,能更真实地反映电网企业数据中心的能效水平。  [结论]  所提方法简单有效,可为电网企业不同数据中心之间的能源效率比较和节能水平评估提供依据。     

Combustion kinetic modeling using multispecies time histories in shock-tube oxidation of heptane

Recently, species time histories have been measured during n-heptane oxidation behind reflected shock waves [D.F. Davidson, Z. Hong, G.L. Pilla, A. Farooq, R.D. Cook, R.K. Hanson, Combust. Flame 157 (2010) 1899–1905]. The highly precise nature of these measurements is expected to impose critical constraints on chemical kinetic models of hydrocarbon combustion. In this paper, we apply the Method of Uncertainty Analysis using Polynomial Chaos Expansions (MUM-PCE) [D.A. Sheen, X. You, H. Wang, T. Løvås, Proc. Combust. Inst. 32 (2009) 535–542] to demonstrate how the multispecies measurement may be utilized beyond simple model validation. The results show that while an as-compiled, prior reaction model of n-alkane combustion can be accurate in its prediction of the detailed species profiles, the kinetic parameter uncertainty in the model remains to be too large to obtain a precise prediction of the data. Constraining the prior model against the species time histories within the measurement uncertainties led to notable improvements in the precision of model predictions against the species data as well as the global combustion properties considered. Lastly, we show that while the capability of the multispecies measurement presents a step-change in our precise knowledge of the chemical processes in hydrocarbon combustion, accurate data of global combustion properties are still necessary to predict fuel combustion.     

Evaluating the measurement uncertainty at hydrogen refueling stations using a Bayesian non-parametric approach

The ability to evaluate measurement error at hydrogen refueling stations plays a vital role in the sustainability of the hydrogen vehicle industry. Most previous work in this application investigates the measurement accuracy of mass flow meters in controlled experiments, using testing equipment. The focus of our work is to estimate the measurement accuracy of fueling using data from hydrogen refueling stations collected under real operation. Accuracy is estimated by comparing the observed mass count readings with reference mass counts calculated using the pressure-volume-temperature method. To quantify the measurement uncertainty, we propose using Dirichlet process mixture models, a class of Bayesian non-parametric methods. The Dirichlet process mixture model approach is tested on five hydrogen refueling stations in real operation. Our results show that the model is able to capture the complex structure of the data and successfully estimate the probability distribution of measurement uncertainty. Our work demonstrates the effectiveness of the Bayesian non-parametric approach for evaluating the measurement uncertainty of hydrogen refueling stations.     

基于电价波动率的现货电价风险度量研究

风险度量因子的选取是风险度量的核心工作之一,统计性质好的指标通常能降低建模复杂度,提高精度。根据电价序列的特征及电价风险度量模型的特点,提出以电价波动率替代电价作为风险度量因子,避开电价序列的非平稳性,建立GARCH-VaR模型用于现货电价风险度量,以北欧电力市场的电价风险度量为例,对模型的可行性和有效性进行检验,并将所提出的电价风险度量方法与电价波动率正态分布法、电价ARMA-GARCH模型度量的电价风险进行比较。结果表明,所提方法不仅能有效降低电价风险度量的模型复杂度,还可提高风险度量的准确性。     

An experimental study on local interfacial area concentration using a double-sensor probe

Interfacial area concentration is an important parameter in modeling the interfacial transfer terms in the two-fluid model. In this paper, the interfacial area concentration, void fraction, and bubble Sauter mean diameter for air-water bubbly flow through a vertical transparent pipe with 40 mm internal diameter was investigated experimentally using both digital high-speed camera system and a double-sensor conductivity probe. Based on the experimental data of digital high-speed camera system, the statistical models derived by different researchers for local interfacial area concentration measurement using double-sensor conductivity probe were evaluated. The results show that there are obvious differences among the values of local interfacial area concentration calculated by different statistical models even from the same probe signals. The section-averaged values of the local interfacial area concentration calculated using the statistical model by Kataoka et al. agree best with experimental data of digital high-speed camera system. Therefore, the statistical model developed by Kataoka et al. is recommended for the local measurement of interfacial area concentration using a double-sensor conductivity probe in bubbly two-phase flow. Using the verified double-sensor probe method, we carry out experiment to study the local distribution characteristic of the interfacial area concentration and void fraction in air-water bubbly flow through a vertical pipe.     

The prediction of effective thermal conductivities perpendicular to the fibres of wood using a fractal model and an improved transient measurement technique

The porous microstructure of wood samples on their sections perpendicular to the fibres were analyzed using the scanning electron microscope images. The fractal dimensions of these images were calculated using the box-counting method, respectively. They are all approximately equal to 1.4, although the distribution and the scale of wood fibres are extremely different. Then, a fractal model for predicting the effective thermal conductivities of wood was established using the thermal resistance method. In addition, we measured the effective thermal conductivity of wood via an improved transient plane source measurement method. The calculated results by the proposed model are in good agreement with the experimental data as well as the literature data. The comparison shows clearly that this fractal model can be used to accurately and effectively predict the effective thermal conductivities perpendicular to the fibres of wood.     

Thermal diffusivity measurement of glass at high temperature by using flash method

A measurement of the thermal diffusivity of a semi-transparent material (glass) by means of the "Flash Method" is investigated in the present work. By taking into account the heat losses on the two faces of the sample, and using a new experimental technique design, an improvement of the determination of the thermal diffusivity of the semi-transparent material (glass) at high temperature is realized. The experimental design presented here is an original technical concept that enables a significant reduction in heat loss during the experiments. A very simple model based on the quadrupole method is used to theoretically determine the thermal diffusivity of the semi-transparent material by taking into account both conduction and radiation. Theoretical results clarify the effect of the absorption coefficient and the thickness of the sample on the heat transfer in the semi-transparent medium.     

基于地下电学特征变化监测城市垃圾场有害液体的渗漏

对城市垃圾场有害液体通过渗漏污染地下水问题的解决已迫在眉睫，而目前对垃圾场有害液体渗漏监测的方法存在各种问题，传统的环境地球物理的方法是垃圾场有害液体渗漏监测的主要手段之一，但该方法存在监测范围少，时间间隔长的缺点。介绍了垃圾渗漏污染的基本机理和使用环境地球物理电阻率法监测渗漏的原理，通过引用了一个数据模拟的例子对比全通道方法与其他传统方法，表明了全通道方法明显的优势。同时讨论了使用永久埋地电极进行数据采集和处理的优点，并且提出该监测方法分阶段的数据处理和解释的主要思路和原理。针对垃圾场的极大市场规模，采用全通道电阻率法作为数据采集方案，可有效对垃圾场进行实时、高效、全方位的监测，可在全行业范围内推广应用。     

插值标定的CCD比色测温方法

介绍了CCD电荷耦合器件和CCD比色测温原理。为减少测温误差，把波长带宽等误差归结到测温公式中的K值中，提出了利用标定实验数据对测温公式中的K值进行插值标定的比色测温方法，给出了插值标定的CCD比色测温的数学模型。     

无损检测阻抗测量特性分析

电磁感应生物阻抗测量方法是一种无损检测方法,具有非接触获得生物电阻抗信息的特征．克服了电极接触阻抗对测量的影响,但其测量结果与被测对象的阻抗特性关系具有很高的复杂性。为了发现其规律性,针对组织测量探头．本文推导了对应的解析解,分析了电导率和提离距离对互感变化的影响,得出了该探头以及与此相关的电磁断层成像（EMT）的测量结果规律性特点。