scholarly journals Numerical analysis of the equipment position influence on the premises thermal regime under gas infrared emitter operation and mixed convection conditions

2021 ◽  
Vol 2119 (1) ◽  
pp. 012092
Author(s):  
B V Borisov ◽  
G V Kuznetsov ◽  
V I Maksimov ◽  
T A Nagornova ◽  
A V Vyatkin
Keyword(s):  
Mathematical Modeling ◽  
Turbulence Modeling ◽  
Radiant Heat ◽  
Solid Surfaces ◽  
Radiant Heat Flux ◽  
Laboratory Equipment ◽  
Incompressible Medium ◽  
One Dimensional ◽  
Exhaust Ventilation ◽  
Infrared Emitter

Abstract The analysis of mathematical modeling results on premise heating by a gas infrared emitter (GIE) during supply and exhaust ventilation operation is presented in this article. The model is presented in a one-dimensional non-stationary setting for an incompressible medium with allowances for the radiant heat flux transfer between opaque solid surfaces in the air. The air is transparent to thermal radiation. The traditional k-ε model is used for turbulence modeling. The possibility for creating comfortable conditions in the area of a horizontal surface with different heights, imitating laboratory equipment, is analyzed.

The ‘piston problem’ with thermal radiation

1964 ◽  
Vol 20 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Kuo Chang Wang
Keyword(s):  
Heat Flux ◽  
Thermal Radiation ◽  
Radiation Effects ◽  
Local Thermodynamic Equilibrium ◽  
Classical Problem ◽  
Radiant Heat ◽  
Radiant Heat Flux ◽  
Piston Problem ◽  
One Dimensional ◽  
Similarity Method

The classical problem of the motion of a one-dimensional unsteady shock generated by a piston moving with velocity vp = ctn is extended to take into account thermal radiation effects by the similarity method of Taylor and Sedov. Gray gas and local thermodynamic equilibrium are assumed and a modification of the Schuster-Schwarzschild differential equation for the heat flux is adopted. The optical thickness is not restricted to be thin or thick, and the absorption coefficient is assumed to vary with the density and temperature. Numerical results indicate that the pressure and velocity are not affected much by the radiation, but the density, temperature and radiant heat flux are changed considerably.

scholarly journals Лучистый тепловой поток от возбужденных атомов в высокочастотном ионном двигателе

2021 ◽  
Vol 47 (4) ◽  
pp. 45
Author(s):  
В.К. Абгарян ◽  
М.В. Абгарян ◽  
А.Б. Надирадзе ◽  
В.В. Нигматзянов ◽  
А.А. Семенов
Keyword(s):  
Heat Flux ◽  
Radio Frequency ◽  
Spontaneous Emission ◽  
Discharge Plasma ◽  
Radiant Heat ◽  
Numerical Calculations ◽  
Radiant Heat Flux ◽  
Ion Thrusters

The radiant heat flux coming from the discharge plasma on the surfaces of radio frequency ion thrusters is considered. Spontaneous emission of photons is formed when the excitation of plasma atoms and ions is removed. The distributions of the densities of the heat flux brought by radiation to the surface in the thrusters are calculated. The distributions can be used in numerical calculations of temperatures in thrusters design.

scholarly journals Experimental study on moisture transfer through firefighters' protective fabrics in radiant heat exposures

2017 ◽  
Vol 21 (4) ◽  
pp. 1665-1671 ◽  
Author(s):  
Meng Chen ◽  
Fanglong Zhu ◽  
Qianqian Feng ◽  
Kejing Li ◽  
Rangtong Liu
Keyword(s):  
Heat Flux ◽  
Moisture Transfer ◽  
Radiant Heat ◽  
Positive Influence ◽  
Heat Radiation ◽  
Radiant Heat Flux ◽  
Thermal Protective Performance ◽  
Protective Fabrics ◽  
Protective Performance ◽  
Radiation Time

The effects of absorbed moisture on thermal protective performance of fire-fighters? clothing materials under radiant heat flux conditions were analyzed in this paper. A thermal protective performance tester and temperature sensor were used to measure the temperature variations for the facecloth side of four kinds of commonly used flame retardant fabrics in several radiant heat exposures, which varied in moisture content. Experimental results showed that, all of the temperature profiles of these four kinds of moistened fabrics under different radiant heat flux conditions presented the same variation trend. The addition of moisture had a positive influence on the thermal protective performance during the constant temperature period when heat radiation time was more than 60 seconds. As the heat radiation time increased beyond 500 seconds, the thermal protective performance of moistened fabrics became worse than that of dried fabrics in general.

Development of a pyrolysis model for oriented strand board: Part II—Thermal transport parameterization and bench-scale validation

2021 ◽  
pp. 073490412110366
Author(s):  
Junhui Gong ◽  
Hongen Zhou ◽  
Hong Zhu ◽  
Conor G McCoy ◽  
Stanislav I Stoliarov
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Loss Rate ◽  
Oriented Strand Board ◽  
Mass Loss Rate ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Controlled Atmosphere ◽  
Radiant Heat Flux ◽  
Pyrolysis Model

Oriented strand board is a widely used construction material responsible for a substantial portion of the fire load of many buildings. To accurately model oriented strand board fire response, kinetics and thermodynamics of its thermal decomposition and combustion were carefully characterized using milligram-scale testing in part I of this study. In the current work, Controlled Atmosphere Pyrolysis Apparatus II tests were performed on representative gram-sized oriented strand board samples at a range of radiant heat fluxes. An automated inverse analysis of the sample temperature data obtained in these tests was employed to determine the thermal conductivities of the undecomposed oriented strand board and condensed-phase products of its decomposition. A complete pyrolysis model was formulated for this material and used to predict the mass loss rates measured in the Controlled Atmosphere Pyrolysis Apparatus II experiments. These mass loss rate profiles were predicted well with the exception of the second mass loss rate peak observed at 65 kW m−2 of radiant heat flux, which was underpredicted. To further validate the model, cone calorimeter tests were performed on oriented strand board at 25 and 50 kW m−2 of radiant heat flux. The results of these tests, including both mass loss rate and heat release rate profiles, were predicted reasonably well by the model.

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