...Tairan Fu; Yehan Xiong; Jiangfan Liu; Congling Shi A method to simultaneously measure two-dimensional temperature and emissivity distributions on high-temperature diffuse surfaces is developed using an auxiliary light source. The high-temperature diffuse surface is irradiated from the hemispherical...

... (10,000–100,000) and curvature ratios (0.02–0.05). The emissivity and optical thickness have been varied from 0.0 to 1.0 and 0.0 to 8.0, respectively, to investigate the effect of thermal radiation on heat transfer characteristics in spiral-coiled tubes. For the considered Reynolds number range...

... Tan. 07 08 2012 07 01 2013 In this note, a new blackbody radiation fraction function is proposed for calculating the emissive power or total emissivity of a surface that has an emissivity depending linearly on wavelength in a wavelength interval. This new fraction function...

... technique. The effects of emissivity of walls and optical thickness on the convergence are investigated. The results indicate that the accuracy of present model is reliable and its accelerative effect is more obvious for the optically thick and scattering dominated media with intensive diffusely reflecting...

... been proposed to enhance a material’s emissivity and its radiative coherence. Control of thermal emission is of crucial concern in the design of infrared sources, in electronic chip coolants, in high-efficiency photovoltaic cells, and in solar energy conversion. In this review paper, we present...

...L. P. Wang; S. Basu; Z. M. Zhang The determination of emissivity of layered structures is critical in many applications, such as radiation thermometry, microelectronics, radiative cooling, and energy harvesting. Two different approaches, i.e., the “indirect” and “direct” methods, are commonly used...

... to make it isoflux. Irrespective of the thermal conductivity of the plate, an increase in the emissivity reduces the average temperature of the plate and brings the plate toward isothermal condition. A new methodology has also been proposed to determine the thermophysical properties, emissivity...

... different velocity field. The wall emissivity has a strong influence on the heat transfer but the scattering albedo does not. Numerous methods have been proposed to solve the RTE numerically. Among the most popular are the spherical harmonics ( P N ) , Monte Carlo, Zonal, discrete...

..., if the absorptivity of the coating, the plate emissivity, the number of protruding fins, and some area and fluid parameters are known, the corresponding value for the base temperature of the fin is immediately obtained. The analysis shows that the thermal performance of the exchanger improves substantially...

...G. Venugopal; M. Deiveegan; C. Balaji; S. P. Venkateshan Transient cooling experiments of a heated vertical aluminum plate with an embedded heater, in quiescent air, were conducted for the simultaneous estimation of total hemispherical emissivity and specific heat of the plate material. During...

... modification process to form micro-column arrays (MCA) on any material for use as highly adaptive radiators. The MCA-structured surfaces have experimentally been shown to have excellent emissive properties. Finite element methods have been used to simulate the temperature profiles for surfaces with and without...

...F. Marquier; M. Laroche; R. Carminati; J.-J. Greffet Thermal emission of a doped silicon grating has been studied in the plane perpendicular to the grooves. We show how the excitation of surface plasmons produce a resonant emission weakly depending on the polarization and azimuthal angle. We...

... is studied for Rayleigh numbers Ra, ranging from 10 3 to 4 × 10 6 and surfaces emissivity ε , varying from 0 to 1. The governing equations, written in terms of stream function-vorticity formulation, are solved using a finite difference approach. It is found that, under these heating/cooling conditions, three...

...B. J. Lee; Z. M. Zhang Enhancement of thermal emission and control of its direction are important for applications in optoelectronics and energy conversion. A number of structures have been proposed as coherent emission sources, which exhibit a large emissivity peak within a narrow wavelength band...

...M. Deiveegan; C. Balaji; S. P. Venkateshan An inverse radiation analysis for simultaneous estimation of the radiative properties and the surface emissivities for a participating medium in between infinitely long parallel planes, from the knowledge of the measured temperatures and heat fluxes...

... generated using a radiometric, direct emission measurement method. The oxide was grown on a very clean, smooth, and mirror-like copper surface, heated in air at 700 ° C until emission measurements became constant ( 270 h ) . X-ray diffraction and EDS analyses were performed to characterize the spatial...

...F. Kowsary; J. R. Mahan An exact analytical method is presented for determination of emissive as well as absorptive performance of spherical cavities having diffuse-specular reflective walls. The method presented utilizes a novel coordinate transformation technique, which provides convenient means...

... , “ Simulataneous Measurements of Specific Heat and Total Hemispherical Emissivity of Chromel and Alumel by a Transient Calorimetric Technique ,” Int. J. Thermophys. 0195-928X , 15 , pp. 547 – 565 . Cheng , S. X. , 1984 , “ An Accurate Transient Calorimeter for Measuring the Total Hemispherical...

... deposition a slow variation in surface emissivity is expected, while the defrosting process is characterized by a sudden change of this property. As an indicator for the defrosting initiation control mechanism, the times at which the IR signals stabilize at different conditions (Reynolds number, cold surface...

... consists of heating the central plate at different levels and recording the temperatures of both the central and the side plates at steady state conditions. Based on the measurements, a correlation for the maximum temperature excess of the “hot” plate in terms of the emissivity of the central and the side...