植被森林多层耦合模式的热辐射的散射和传输

本文提出应用于植被和森林热辐射遥感的多层随机介质耦合模式,得到了多层热辐射耦合和多次散射的矢量辐射传输方程的数值解。辐射亮度温度的数值结果与实验数据进行了很好的比较;并对参数规范化选取,辐射亮度温度与频率、极化,植被森林含水量、层高等有关参数的函数关系进行了讨论。

散射对高温气体⁃碳黑颗粒混合物辐射传输的影响

基于全光谱k分布(Full spectrum k distribution,FSK)模型、MIE理论和有限体积法(Finite volume method,FVM),构建了均温、均质辐射参与性气体-碳黑颗粒混合物介质热辐射传输模型,并分析了碳黑不同尺寸、不同体积浓度以及介质不同路径长度和不同温度条件下,因忽略碳黑颗粒散射所导致的介质热辐射传输特性(如辐射热流、辐射源项)的计算误差。研究结果表明:体积分数不变,增大粒径,计算误差呈现出先增大后减小的趋势;数密度不变,增大粒径,或者粒径不变,增大体积分数,均将使得计算误差相应增大;粒径、体积分数不变,增大路径长度,或者升高介质温度,均将增大计算误差。通常对于含有大颗粒、高碳黑浓度的辐射参与性气体-碳黑颗粒混合物介质,碳黑颗粒散射不能忽略。

Enhancement of heat radiative characteristics of coatings by ultra-attenuation

The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.

城市区域几何效应的辐射校正及其温度遥感反演

开展适用于城市地区热红外遥感图像几何效应的辐射校正物理模型研究,对提升城区下垫面温度反演精度具有重要作用。本文利用天空视域系数SVF(Sky View Factor,V)量化城区下垫面几何特征,并考虑几何特征对地物目标辐射传输的影响机理。将遥感传感器入瞳处的辐射亮度分解为地物目标发射辐射、地物目标反射辐射以及大气上行路径辐射3部分,并分析了各部分辐射在"城区—大气"界面的辐射传输过程,构建适用于城市下垫面的热辐射传输UTRT(Urban Thermal Radiation Transfer)模型,可应用于城区热红外遥感图像的几何效应辐射校正。基于Landsat 8 TIRS(Thermal Infrared Sensor)数据,将UTRT模型应用于北京市典型城区地表温度的反演,并对UTRT模型和不考虑下垫面几何特征反演结果进行对比分析,结果显示:(1)研究区内UTRT模型反演结果数值上整体低于不考虑下垫面几何特征的反演结果,差值范围为0—1.57 K,均值为0.44 K;(2)通过对不同地表覆被类型的分析对比,模型结果差值较大的区域为建筑和裸地,其空间分布明显受V值的影响,在一定范围内,V值越大反演结果数值越低;(3)对UTRT模型天空视域系数和环境温度两个参数进行敏感性分析,在地表发射率较小的场景中V参数敏感性较强,由于环境温度与目标地物温度较为接近,其参数的敏感性较低。结论为:UTRT模型可为城市下垫面遥感图像几何效应的辐射校正提供解决方案,对比不考虑下垫面几何特征的模型,前者可以更好地应用于城区地表温度遥感反演。该研究对推进城市高分辨率热红外定量遥感具有发展潜力和应用前景。

The Imaginary Plane Mothod of Radiation Heat Transfer in The Freeboard of Atmospheric Bubbling Fluidized Bed Boiler

An imaginary plane method for calculation of radiative heat trensfer and its application in the freeboard of AFBC boiler is presented in this paper. The combustion reaction and particle concentration are taken into account in this method. With is method, one-dimensional freeboard model for radiative heat transfer has been made. Results from this model have been compared with the experimental results of a 130 t/h AFBC boiler. The distribution of flue gas temperature and heat flux at the waterwell are obtained. It is shown that this model has the advantage of good accuracy and requiring less computation time. The applicability of the predicted results in the AFBC boiler design and operation was also discussed.