气体污染物的红外辐射特性

基于 HITRAN Database给出的谱线参数 ,利用逐线计算方法计算了 SO2 ,CO,N2 O,NO,NO2等气体污染物的红外辐射特性 ,给出了总压为 1atm、温度为 2 96K、波数范围 4 0 0～ 80 0 0内气体污染物的吸收系数分布图。为便于比较 ,同时给出了水蒸汽和二氧化碳气体的吸收系数分布图。     

碳纤维电热元件红外辐射特性研究

以碳纤维远红外管状电热元件为研究对象,研究了辐射反射罩的曲率及排布位置对辐射特性的影响,为获得均匀稳定的辐射场提供了参考。对比了几种不同类型的加热元件反射系统,结果表明碳纤维红外辐射反射系统的加热效果明显,加热质量较高。     

TiN-导热油纳米流体辐射特性实验研究

通过实验研究了两步法制备的T iN‐导热油纳米流体的辐射特性,测量了纳米流体的导热系数、常规透射率及半球透、反射率,还研究了质量分数以及光程对其透射率、反射率的影响。实验结果表明,质量分数为0．010％的T iN‐导热油纳米流体对辐射能的吸收效果最好,吸收率为97％左右,且其导热系数大于基液的导热系数,可以在一定程度上提升太阳能集热器的集热效率。因此,其在太阳能的高效利用方面具有较好的潜力。     

不同条件下海面热尾流红外辐射特性研究

综合考虑波动海面的遮挡和周围环境对热尾流辐射亮度的影响,建立了热尾流红外辐射模型。通过计算3~5μm和8~12μm两个大气窗口下探测器接收到的热尾流红外辐射亮度,得到了热尾流红外辐射特性与风速、探测器高低角和尾流温度之间的关系。从红外探测的角度,利用辐射对比度参量研究了热尾流目标与海洋背景在探测器处的差别,得到了热尾流与海洋背景的对比度在风速和探测器天顶角变化时的变化规律。研究结果为海面热尾流的红外探测提供了理论参考。     

高温宽粒径氧化铝颗粒辐射特性研究

基于Mie散射理论研究了温度分布为400～1 000℃,粒径分布为0.1～20.0 mm的单个氧化铝颗粒的辐射特性参数。研究发现,当温度处于400～1 000℃时,直径为3.0 mm的氧化铝颗粒已基本满足大粒子辐射特性,而0.1～3.0 mm的氧化铝颗粒衰减效率因子、散射效率因子、吸收效率因子随粒径的增加而急剧衰减,散射反照率随粒径的增加而急剧增加。基于最小二乘法对温度分布为400～1 000℃,粒径分布为0.1～3.0 mm的氧化铝颗粒辐射特性效率因子进行拟合,拟合优度达到0.999以上,表明可以利用此非线性回归方程对此温阈、粒阈氧化铝颗粒辐射特性效率因子进行较精确的计算。     

高温红外辐射涂料的研制及其节能效果

以MnO2、Fe2O3、CuO、Co2O3等过渡金属氧化物经高温固相反应形成尖晶石结构的红外陶瓷粉料,然后与硅酸盐粘接剂混合制备出红外辐射节能涂料。采用XRD、红外辐射测量仪等对材料的结构和理化性能进行了表征。通过实验数据的分析,研究了高温红外辐射节能涂料的节能效果。结果表明,涂层具有良好的红外辐射性能,全波段辐射率最高达0.90。在热风炉高铝砖耐火材料表面使用该高温红外辐射节能涂料后,在实验条件为600℃下蓄热量提高5%,1 200℃时蓄热量提高21%。涂覆红外辐射节能涂料后不锈钢容器的吸热和热交换能力明显增加,能耗可降低28%左右。     

辐射致冷用氮化硅薄膜的微观结构和光学性质

采用射频等离子体化学气相沉积（PECVD）法制备了SiNx薄膜,用X－射线荧光光谱,红外吸收光谱,红外反射光谱以及扫描电镜对薄膜的成分,结构,表面形貌和光学性质进行了步研究,X－射线荧光分析表明SiNx薄膜的组成为SiN0.35,从红外透过光谱可见,氮参加了反应并生成Si-N键,薄膜中有少量的Si－H键和N－H键,红外反射光谱表明SiN0.35薄膜是非常好的窗口材料,在8－13um波段内具有很低的反射率,8－13um波段外反射率高,适合制备辐射制冷体,SEM观察结果对薄膜的表面形态和生长机量给予了初步解释。     

高温红外辐射釉料的应用研究

高温红外辐射釉料是一种非晶态结构的耐高温、热辐射率高、具有抗渗碳、耐腐蚀的新型红外辐射节能材料.测试和统计表明,辐射管涂敷高温红外辐射釉料后,温度均匀性得到很大改善、变形减小、寿命延长、热效率提高、节能显著.     

福建省太阳总辐射和地面辐射平衡的分布

首先利用福州市的辐射观测资料，建立计算太阳总辐射的经验公式，并计算福建省各市、县的太阳总辐射的年、月平均辐照度。然后利用地区代表站的地面反射率，求得福建省各月、年地面所吸收的太阳辐射能的分布。再利用地面温度、气温、水汽压和总云量，计算得出福建省各地的地面有效辐射的月、年平均辐照度。最后得出福建省各月、年地面辐射平衡的分布。     

冷辐射板吸收太阳辐射的特性研究

为计算辐射空调系统中冷辐射板吸收太阳辐射能的大小及比例,在分析室内太阳光线传播的基础上,提出采用一种线性方程的方法.结果表明,以本文房间为例,冷辐射板吸收的太阳辐射能的大小以及比例在夏至日表现为正午最小,冷辐射板所吸收的太阳辐射能理论上最大能达到32 W/m2,吸收系数在0.13～0.28之间变化.冷辐射板所吸收的太阳...     

Single-layer heat mirror films and an improved method for evaluation of its optical and radiative properties in infrared

A technique for preparing single heat mirror films with high quality is described. We also present an improved method for evaluating its optical and thermal radiative properties in the infrared region (2.5<λ<25 μm). The calculated results agree well with that obtained by experimental measurements. The results calculated by using the simple Hagen–Rubens relation are also given. It is shown that the Hagen–Rubens relation is not accurate to predict the thermal radiative properties for the transparent semiconducting oxide films, such as indium tin oxides, prepared in our studies.     

Microstructure and optical properties of silicon nitride thin films as radiative cooling materials

SiN_X thin films were prepared by the RF plasma-enhanced chemical vapor deposition method. Composition, structure, surface morphology and optical properties of the thin films were analyzed by X-ray fluorescence, IR transmittance, IR reflectance and SEM. The results show that the composition of the films is SiN_0.35. Nitrogen atoms take part in the reaction with silicon atoms and Si–N bonds are formed. There are also some Si–H and N–H bonds in the films. The films have very low hemispherical IR reflectance across the full 8–13 μm band and high hemispherical reflectance elsewhere, which indicates that silicon nitride films can be used as good radiative cooling materials. The surface morphology and growth mechanisms of the films were also explained.     

Infrared radiative properties of anodized aluminium

Measurements of anodic film thicknesses and their total hemispherical thermal emittance for various current densities (0.55–3.85 ampere/dm²), anodizing times (1–20 min), and oxalic acid concentrations (1–6 wt.%) show a linear relationship between the film thickness and the total hemispherical thermal emittance (?). Changes in oxalic acid concentration (2–4 wt.%) have no significant effect on the film growth-rate and the rate at which ? increases with increasing anodizing time. Measurements of ? for wavelengths form 3 to 30 μm show that the film growth-rate has a marked effect on the i.r. radiative properties of aluminium.     

Thermal Radiative Properties of Xonotlite Insulation Material

Introduction Xonotlite-type calcium silicate (6CaO?6SiO2?H2O) is synthesized porous insulation material by hydrothermal processing with quartz powder and limestone as the raw material (with CaO/ SiO2≈1:1). Compared with fire- retardant fibre, xonotlite has more excellent insulating performance, such as low thermal conductivity, environment friendly, high intension, and wide applying temperature range, which has been emphasized in recent years by many scholars and widely used in many indu…     

Spatial and radiative properties of an open-flame hydrogen plume

Considerable effort is being directed toward updating safety codes and standards in preparation for production, distribution, and retail of hydrogen as a consumer energy source. In the present study, measurements were performed in large-scale, vertical flames to characterize the dimensional and radiative properties of an ignited hydrogen jet. These data are relevant to the safety scenario of a sudden leak in a high-pressure hydrogen containment vessel. Specifically, the data will provide a technological basis for determining hazardous length scales associated with unintended releases at hydrogen storage and distribution centers. Visible and infrared video and ultraviolet flame luminescence imaging were used to evaluate flame length, diameter and structure. Radiometer measurements allowed determination of the radiant heat flux from the flame. The results show that flame length increases with total jet mass flow rate and jet nozzle diameter. When plotted as a function of Froude number, which measures the relative importance of jet momentum and buoyancy, the measured flame lengths for a range of operating conditions collapse onto the same curve. Good comparison with hydrocarbon jet flame lengths is found, demonstrating that the non-dimensional correlations are valid for a variety of fuel types. The radiative heat flux measurements for hydrogen flames show good agreement with non-dimensional correlations and scaling laws developed for a range of fuels and flame conditions. This result verifies that such correlations can be used to predict radiative heat flux from a wide variety of hydrogen flames and establishes a basis for predicting a priori the characteristics of flames resulting from accidental releases.     

Thermal radiative properties of a smooth air-water interface

Thermal radiative properties for an air-water interface were calculated by considering the interface to be smooth and the water to be at uniform temperature. Monochromatic hemispherical and total normal reflectance, monochromatic and total normal transmittance, Planck mean and Rosseland mean absorption coefficients were evaluated. The wavelength interval covered by the calculations was between 0.2 and 200 μ. Other thermal radiative properties, such as emittance and absorptance, were related to the above properties, and a comparison with available results shows favorable agreement. The use of these properties in the area of remote sensing and global energy balance makes the data essential for identifying the most effective region of the spectrum and for explaining some of the naturally occurring processes where radiative transfer plays an important role.     

Measuring and evaluating solar radiative properties of plastic shading nets

Plastic shading nets are being used extensively in hot and sunny regions to protect plants from intense solar radiation. Different varieties of these nets are commercially available. However, the choice of net to fulfill specific shading requirements often depends on empirical or economic criteria and not on scientific considerations because essential information used to characterize the different types of nets is not available.In order to replace expensive measuring facilities that use artificial lighting to investigate the radiative properties of plastic shading nets, a simple method was presented to investigate these properties under global, diffuse and direct beam solar radiation conditions. Measurements were performed on clear sunny days, (December 28, 2008-February 10, 2009). Nets with colors and shading factors that are most commonly used in hot regions were selected for the study. The results showed that the behaviors of the plastic nets under solar radiation conditions were similar to those of translucent materials. Accordingly, it is possible to (i) treat plastic nets as translucent materials and (ii) investigate the equivalent optical constants (i.e., refractive indexes and extinction coefficients) for plastic nets as functions of the net solidity, texture type and color. Solidity and color of the net had significant effects on the radiative properties and the effect of color was much more than the effect of solidity. The shading factor of a plastic net, is a function of the daytime, depends on several design and meteorological parameters, so it cannot be used to describe a net. However, the net solidity together with color, and the daily integrals of the shading factor and of the radiative properties are appropriate parameters for describing a net.     

Directional radiative properties of anisotropic rough silicon and gold surfaces

Recent studies have shown that the topography of some chemically etched microrough silicon surfaces is non-Gaussian and may be strongly anisotropic. However, the bidirectional reflectance distribution function (BRDF) of anisotropic surfaces has not been fully understood. The present study uses the Monte Carlo method to investigate the out-of-plane BRDF, multiple scattering, and the change of the polarization state upon reflection. Two ray-tracing algorithms are developed that incorporate the surface topography or slope distribution of the samples obtained by the use of an atomic force microscope. The predicted BRDFs for silicon surfaces with or without a gold coating are in reasonable agreement with the results measured using a laser scatterometer at a wavelength of 635 nm. The employment of surface topographic data is indispensable to the BRDF modeling of anisotropic surfaces. While first-order scattering makes the dominant contribution to reflections from the studied surfaces, it is critical to consider the polarization state change in order to correctly predict the out-of-plane BRDF. The versatile Monte Carlo modeling tools developed through the present study help gain a better understanding of the directional radiative properties of microrough surfaces and, furthermore, will have an impact on thermal metrology in the semiconductor industry.     

Experimental and RDFI calculated radiative properties of a mullite foam

The solid phase of a mullite foam has been experimentally characterized as a mainly scattering semi transparent medium with an isotropic phase function. In a second step, from the corresponding determined data, the Radiative Distribution Function Identification (RDFI) method of Zeghondy et al. has been applied to predict the bi-directional reflectance of a mullite foam sample. A direct experimental determination of this reflectance agrees with the model results.     

Infrared radiative properties of polymer coatings containing hollow microspheres

Infrared radiative properties of a polymer containing hollow glass microspheres are studied by means of the measurements of directional-hemispherical reflectance and transmittance in the wavelength range from 2.6 to 18 μm. The measurements are performed for several samples containing different series of microspheres of volume fraction from about 6% to 66%. Relatively strong peak of reflectance at the wavelength 4.5 μm was observed. This peak is explained in terms of theoretical model based on Mie theory calculations for single microspheres and modified two-flux approximation proposed recently by the authors. The reflectance of the composite material in the important range from 8.5 to 13.5 μm is determined mainly by rough surface layer of microspheres and it does not described by the model for semi-transparent media. The conditions of a considerable decrease in radiative heat losses from the buildings due to paint coatings containing hollow glass microspheres are discussed.