An Experimental/ Analytical Technique of Determining Reflection Parameters for Evaluation of Thermal Radiation Energy Exchange between Real Surfaces

2002 ◽  
Author(s):  
Toshiro Makino ◽  
Hidenobu Wakabayashi
Keyword(s):  
Thermal Radiation ◽  
Energy Exchange ◽  
Radiation Energy ◽  
Analytical Technique

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.

The Thermocouple Revisited: The Thomson Effect

2019 ◽  
Vol 44 (4) ◽  
pp. 333-353
Author(s):  
Paul B. Jacovelli ◽  
Ronald C. Norris ◽  
Chester E. Canada ◽  
Otto H. Zinke
Keyword(s):  
Thermal Radiation ◽  
Energy Exchange ◽  
Three Dimensions ◽  
Thermodynamic Approach ◽  
Thomson Effect ◽  
Equilibrium Thermodynamic ◽  
Ambient Temperatures ◽  
Silver Sample ◽  
Lord Kelvin ◽  
Made In

Abstract Measurements of Thomson (later Lord Kelvin) coefficients are made in an evacuated region on a silver sample with a novel transducer in temperature intervals {T_{A}}\pm 20\hspace{0.1667em}\text{K}, where the {T_{A}} are very carefully controlled ambient temperatures. This is the first systematic examination of Thomson coefficients in these temperature intervals. The Thomson coefficients when plotted against T, the temperature of measurement, are found to be discontinuous precisely at {T_{A}}. When the Thomson coefficients are multiplied by a transformation involving T and {T_{A}}, a linear curve in T results. Examinations here of measurements of Thomson coefficients produced by others show multiple values at T in some cases and odd behavior in other cases. Multiplying the results of others by the transformation discovered here almost always produces linear curves. The conclusions are the following. (1) Thomson’s explicit assumption that the Thomson effect involves no energy exchange with surroundings was wrong. (2) Any non-equilibrium thermodynamic approach to deriving the Thomson effect must take into account the energy exchange with the surroundings and consequently must be made in three dimensions. (3) From the work here and that of others, the energy exchange with the environment is probably mostly thermal radiation.

Soret, Dufour and radiation effects of a viscoelastic fluid on an exponentially stretching surface using the Catteneo–Christov heat flux model

2020 ◽  
Vol 16 (6) ◽  
pp. 1577-1594
Author(s):  
Kazeem Babawale Kasali ◽  
Yusuf Olatunji Tijani ◽  
Matthew Oluwafemi Lawal ◽  
Yussuff Titilope Lawal
Keyword(s):  
Thermal Radiation ◽  
Chemical Reaction ◽  
Viscoelastic Fluid ◽  
Radiation Effects ◽  
Stretching Sheet ◽  
Content Type ◽  
Analytical Technique ◽  
Cross Diffusion ◽  
Exponentially Stretching Sheet ◽  
Exponentially Stretching

PurposeIn this paper, we studied the steady flow of a radiative magnetohydrodynamics viscoelastic fluid over an exponentially stretching sheet. This present work incorporated the effects of Soret, Dufour, thermal radiation and chemical reaction.Design/methodology/approachAn appropriate semi-analytical technique called homotopy analysis method (HAM) was used to solve the resulting nonlinear dimensionless boundary value problem, and the method was validated numerically using a finite difference scheme implemented on Maple software.FindingsIt was observed that apart from excellence agreement with the results in literature, the results obtained gave further insights into the behaviour of the system.Originality/valueThe purpose of this research is to investigate heat and mass transfer profiles of a MHD viscoelastic fluid flow over an exponentially stretching sheet in the influence of chemical reaction, thermal radiation and cross-diffusion which are hitherto neglected in previous studies.

Evaluation of Thermal Radiation Simulator Rectangular Pulse Characterization Methods

1991 ◽  
Author(s):  
Richard B. Loucks
Keyword(s):  
Thermal Radiation ◽  
Temperature Profile ◽  
Thermal Environment ◽  
Front Surface ◽  
Radiation Energy ◽  
Rectangular Pulse ◽  
Liquid Oxygen ◽  
Characterization Methods ◽  
Thermal Output ◽  
Thermal Pulses

Abstract The thermal output of an aluminum powder/liquid oxygen Thermal Radiation Simulator (TRS) is approximated to that of a rectangular pulse. The output varies as a function of time. The rise and fall times are not relatively abrupt. The problem is how to quantify the thermal output of the TRS into terms of a rectangular pulse. Within the nuclear weapons effects community, flux, or the transient intensity of thermal radiation energy onto a surface, and fluence, the total energy irradiated onto a surface over a given time, are the determining parameters for specifying or evaluating an article’s survivability in the thermal environment. Four methods are used to determine the TRS output for these two parameters, assuming the output to be a perfect rectangular pulse. It was essential to determine which of the four methods best quantified the thermal output average flux and fluence. The four methods were compared by a computational experiment run on a personal computer. The experiment was a simulation of five actual TRS traces irradiated onto a fictitious aluminum plate. The temperature profile of the front surface was computed using a finite difference method calculation. The traces were evaluated using the four characterization methods, generating twenty ideal thermal pulses. The temperature profile of the plate was computed using the twenty ideal thermal pulses. The resulting profiles were compared to profiles generated by the actual data to determine which of the characterization methods best evaluated the TRS output.

Ionizing radiation energy exchange in p-terphenyl single-crystalline and composite scintillators

2008 ◽  
Author(s):  
Nikolai Z. Galunov ◽  
Natalya L. Karavaeva ◽  
Jong Kyung Kim ◽  
Yong Kyun Kim ◽  
Oleg A. Tarasenko ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Energy Exchange ◽  
Radiation Energy ◽  
Single Crystalline

scholarly journals HOURLY CALCULATION METHOD OF BUILDING ENERGY DEMAND FOR SPACE HEATING AND COOLING BASED ON STEADY-STATE HEAT BALANCE EQUATIONS

2012 ◽  
Vol 18 (3) ◽  
pp. 356-368 ◽  
Author(s):  
Edmundas Monstvilas ◽  
Vytautas Stankevicius ◽  
Juratė Karbauskaitė ◽  
Arunas Burlingis ◽  
Karolis Banionis
Keyword(s):  
Absorption Coefficient ◽  
Thermal Radiation ◽  
Thermal Energy ◽  
Calculation Method ◽  
Energy Flow ◽  
Energy Demand ◽  
Radiation Energy ◽  
Short Wave ◽  
Radiation Absorption ◽  
Heating And Cooling

Correct evaluation of solar heat gains through fenestration into the rooms has a great impact on energy demand calculations for buildings. This article presents an hourly energy demand calculation method for heating and cooling, which considers the fact that the solar radiation flow passed through the transparent fenestration into the rooms is not adequate to the thermal energy flow. This method considers that the thermal energy flow in the rooms transformed from solar thermal radiation depends on the short-wave thermal radiation absorption coefficient of internal surfaces of the rooms. The value of short-wave thermal radiation absorption coefficient forms a considerable impact on the flow of thermal energy gains in the room. The presented method differs from others on that score that it considers additionally physical lows, according to which the solar short-wave thermal radiation energy admitted into the room is converted into the thermal energy. This hourly method enables precise calculating the hourly mean of indoor temperature and energy demand for heating and cooling of the buildings during the day.

A Solar Thermophotovoltaic System Using Spectrally Controlled Monolithic Planar Thermal Emitter/Absorber

2016 ◽  
Author(s):  
Hiroo Yugami ◽  
Asaka Kohiyama ◽  
Makoto Shimizu ◽  
Fumitada Iguchi
Keyword(s):  
Thermal Radiation ◽  
High Efficiency ◽  
Radiation Spectrum ◽  
Spectral Response ◽  
Storage System ◽  
Radiation Energy ◽  
System Efficiency ◽  
Lower Efficiency ◽  
Pv Cell ◽  
Thermal Emitter

Solar-thermophotovoltaic system is expected to have high efficiency by converting wide spectral range solar energy into useful thermal radiation energy. However, the experimental STPV system shows much lower efficiency than theoretical one. To achieve high-efficiency, it is essential to obtain good spectrally matching between thermal radiation spectrum and PV cells spectral response. In this paper, the power generation tests using the whole configuration of the STPV system is described. The conversion efficiency of GaSb PV cell is estimated to be 20 to 23% against to the light intensity irradiated on the PV cell surface. The net system efficiency of 1.9% can be achieved. The application of thermal storage system to the STPV is also considered.

INVESTIGATION OF THERMAL RADIATION ANGULAR AND POLARIZATION CHARACTERISTICS OF ONE-DIMENSIONAL PHOTONIC STRUCTURES ON A FINITE SUBSTRATE

2021 ◽  
Vol 56 ◽  
pp. 83-88
Author(s):  
V. P. Maslov ◽  
Keyword(s):  
Thermal Radiation ◽  
Experimental Studies ◽  
Radiation Energy ◽  
Infrared Range ◽  
Photonic Structure ◽  
Ir Radiation ◽  
Directional Diagram ◽  
One Dimensional ◽  
Photonic Structures ◽  
Polarization Characteristics

One-dimensional photonic structures (PS) are the layered metamaterials, which optical properties are due to interference effects within the structure. Due to the interaction of electromagnetic waves with the periodic structure, the thermal radiation (TR) of such PS has the features of coherent: it has a selective spectrum and a petal pattern. The relevance of TR PS research is due to the search for new materials to create sources of infrared (IR) radiation in the middle and far IR range (with a wavelength > 5 μm). The second important area of application of the radiating properties of the PS is the creation of non-radiating coatings to remove unwanted TR from the heated surfaces of the IR devices. Despite the fact that the irradiative properties of PS have been studied quite well, in the literature insufficient attention is paid to the influence of the finite substrate on the parameters of TR structures. The influence of a finite incoherent substrate on the angular and polarization characteristics of the thermal radiation of the system (photonic structure)/substrate has been investigated. Systems consisting of plane-parallel Ge or Si plates as PS and incoherent BaF2, BaF2/Al and Al substrates were used in experimental studies. It has been established, the contrast and amplitude of the directional diagram petals of the TR system depend on the ratio of the optical characteristics of the photonic structure and the substrate. The presence of a strongly reflective substrate eliminates the difference between the angular dependences of the s- and p-polarized components of the TR. In the case when the PS is placed on a transparent incoherent substrate with a lower refractive index, there is an increase in the p-polarized component of the TR and the suppression of the s-polarized. The thermal imaging picture of the TR angular distribution of the Si/Al system has been recorded and it was experimentally proved that the TR of photonic systems exhibits circular patterns. The results of the work can be used in the development of narrowband emitters in the middle and far infrared range, coatings to increase radiation energy exchange and coatings with minimal emissivity that are invisible in the thermal range.

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