Thermal radiation exchange of the human by partitional calorimetry.

1967 ◽  
Vol 23 (2) ◽  
pp. 248-258 ◽  
Author(s):  
A P Gagge ◽  
J D Hardy
Keyword(s):  
Thermal Radiation ◽  
Radiation Exchange ◽  
Partitional Calorimetry

Effect of Specularly Reflecting Gray Surface on Thermal Radiation Through a Tube and From Its Heated Wall

1963 ◽  
Vol 85 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. Perlmutter ◽  
R. Siegel
Keyword(s):  
Thermal Radiation ◽  
Surface Temperature ◽  
Circular Tube ◽  
Internal Surface ◽  
Heated Wall ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
Radiation Exchange ◽  
Specular Reflections ◽  
Black Surface

An analysis was made of specular radiation exchange within a circular tube open at both ends and in vacuum. The tube is exposed to thermal radiation from an environment at each end and can have a uniform heat flux supplied at its wall. The external surface of the tube wall is insulated, while the internal surface is a gray, specular (mirrorlike) reflector for thermal radiation. The integral equations governing the radiation exchange are solved to determine the internal surface temperature and the amount of heat transmitted through the tube from the environment at one end to the other. Specular reflections were found to reduce the maximum surface temperature of the heated wall as compared with diffuse reflections, and in some instances the maximum temperature was below the value for a black surface. The energy transmitted through the tube was larger for the specularly reflecting wall than for diffuse reflections. It was also shown that the energy transmitted for a diffusely reflecting gray wall is the same as for a black wall.

Particle-Scale Investigation of Thermal Radiation in Nuclear Packed Pebble Beds

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Hao Wu ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
Shengyao Jiang
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Particle Diameter ◽  
Transfer Model ◽  
Wall Region ◽  
Surface Emissivity ◽  
Radiation Model ◽  
Particle Radiation ◽  
Radiation Exchange ◽  
Effective Particle

For the heat transfer of pebble or granular beds (e.g., high temperature gas-cooled reactors (HTGR)), the particle thermal radiation is an important part. Using the subcell radiation model (SCM), which is a generic theoretical approach to predict effective thermal conductivity (ETC) of particle radiation, particle-scale investigation of the nuclear packed pebble beds filled with monosized or multicomponent pebbles is performed here. When the radial porosity distribution is considered, the ETC of the particle radiation decreases significantly at near-wall region. It is shown that radiation exchange factor increases with the surface emissivity. The results of the SCM under different surface emissivity are in good agreement with the existing correlations. The discrete heat transfer model in particle scale is presented, which combines discrete element method (DEM) and particle radiation model, and is validated by the transient experimental results. Compared with the discrete simulation results of polydisperse beds, it is found that the SCM with the effective particle diameter can be used to analyze behavior of the radiation in polydisperse beds.

Thermal Radiation Energy Exchange Shape Factors for Non-Lambertonian Surfaces

1962 ◽  
Vol 84 (3) ◽  
pp. 271-272 ◽  
Author(s):  
Roy W. Blanton ◽  
K. G. Picha
Keyword(s):  
Thermal Radiation ◽  
Energy Exchange ◽  
Radiation Energy ◽  
Radiation Emission ◽  
Shape Factors ◽  
Radiation Exchange ◽  
Exchange Processes ◽  
Electrical Conductors

Real surfaces involved in thermal radiation exchange processes do not emit or reflect radiation with equal intensity in all directions, i.e., the surfaces are not diffuse. Shape factors for two geometrical cases for surfaces which are electrical conductors are presented as well as an estimate of the error resulting from assumed Lambertonian radiation emission for one case.

A thermal radiation exchange model of whole-body UV phototherapy

2020 ◽  
Vol 6 (5) ◽  
pp. 055023
Author(s):  
A J Coleman ◽  
G A Aneju ◽  
P Freeman ◽  
F Fedele
Keyword(s):  
Thermal Radiation ◽  
Exchange Model ◽  
Whole Body ◽  
Radiation Exchange

Effect of thermal radiation exchange between boundaries on convection in a gas heated from below

1993 ◽  
Vol 27 (5) ◽  
pp. 639-642 ◽  
Author(s):  
S. V. Rusakov ◽  
O. L. Rusakova ◽  
E. L. Tarunin
Keyword(s):  
Thermal Radiation ◽  
Radiation Exchange

Radiation Exchange in an Enclosure With Directional Wall Properties

1965 ◽  
Vol 87 (3) ◽  
pp. 388-396 ◽  
Author(s):  
J. T. Bevans ◽  
D. K. Edwards
Keyword(s):  
Thermal Radiation ◽  
Computational Methods ◽  
Specular Reflection ◽  
The Third ◽  
Radiation Exchange ◽  
First Approximation ◽  
Radiation Properties ◽  
Radiant Exchange ◽  
Directional Characteristics ◽  
Method Of Solution

Three methods of increasing exactness are given for calculating the radiant exchange within a multisurface enclosure made up of “real” surfaces. The first approximation considers the directional characteristics of the thermal radiation properties but does not include specular interreflections. The second method incorporates an approximation for specular reflection as well as the directional behavior of real materials. Solutions of the radiant exchange within an enclosure by these two methods are shown to be no more complex than existing techniques for perfectly diffuse enclosures [1, 2]. The third approximation, while more exact, involves a more detailed but not impractical method of solution. Comparisons of the three approximations to the nondirectional diffuse and specular computational methods [8, 9] are presented, and the importance of considering the directional characteristics of thermal radiation properties is shown.

scholarly journals Radiation Exchange at Greenhouse Tilted Surfaces under All-Sky Conditions

2021 ◽  
Author(s):  
Erick K. Ronoh
Keyword(s):  
Thermal Radiation ◽  
Thermal Environment ◽  
Shortwave Radiation ◽  
Material Surface ◽  
Climate Control ◽  
Surface Design ◽  
Clear Sky ◽  
Radiation Exchange ◽  
Surface Inclination ◽  
Sky Conditions

Greenhouses generally exhibit a greater degree of thermal radiation interaction with the surroundings than other buildings. A number of greenhouse thermal environment analyses have handled the thermal radiation exchange in different ways. Thermal radiation exchange at greenhouse surfaces is of great interest for energy balance. It dominates the heat transfer mechanisms especially between the cover material surface and the surrounding atmosphere. At these surfaces, the usual factors of interest are local temperatures and energy fluxes. The greenhouse surfaces are inclined and oriented in various ways and thus can influence the radiation exchange. The scope of this work is determination of the thermal radiation exchange models as well as effects of surface inclination and orientation on the radiation exchange between greenhouse surfaces and sky. Apart from the surface design and the thermal properties of the cover, the key meteorological parameters influencing longwave and shortwave radiation models were considered in detail. For the purpose of evaluating surface inclination and orientation effects, four identical thermal boxes were developed to simulate the roof and wall greenhouse surfaces. The surface temperatures and atmospheric parameters were noted under all-sky conditions (clear-sky and overcast). Differences in terms of surface-to-air temperature differences at the exposed roof and wall surfaces as influenced by surface inclination and orientation are discussed in this work. Overall, the findings of this work form a basis for decisions on greenhouse design improvements and climate control interventions in the horticultural industry.

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