Three-Dimensional Formulation of the Radiant Heat Flux Variation on a Cylinder Engulfed in Flames

1985 ◽  
Vol 107 (4) ◽  
pp. 949-952 ◽  
Author(s):  
M. M. Tunc¸ ◽  
A. Karakas¸
Keyword(s):  
Heat Flux ◽  
Three Dimensional ◽  
Radiant Heat ◽  
Maximum Amount ◽  
Cylinder Surface ◽  
Radiant Heat Flux ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Flux Variation ◽  
Flame Shape

A three-dimensional formulation is used to determine the incident radiant heat flux on a cylinder surface which is engulfed in flames. For an axisymmetric horizontal pool fire of a specified flame shape, effective flame radiation temperature and a gray flame absorption coefficient, this analysis computes the variation of the incident radiant heat flux along the length and around the circumference of the tank portrayed as a cylinder, engulfed in flames. The radiant flux density from the flame to the cylinder becomes maximum toward the center of the pool and decreases markedly toward the edges. The points which are receiving the maximum amount of radiation heat flux around the circumference of the cylinder are also determined.

Thermal Radiation From Vertical Turbulent Jet Flame: Line Source Model

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Kuibin Zhou ◽  
Juncheng Jiang
Keyword(s):  
Heat Flux ◽  
Line Source ◽  
Radiant Heat ◽  
Source Model ◽  
Radiant Heat Flux ◽  
Emissive Power ◽  
Jet Flame ◽  
New Model ◽  
Flame Shape ◽  
Line Source Model

It is often reported that a jet fire occurs in industrial installations or in the transportation of hazardous materials and could amplify the scale of accident by imposing lots of heat on people and nearby facilities. This paper presents a new semi-empirical radiation model, namely, the line source model to predict the radiant heat flux distribution around a vertical turbulent hydrocarbon jet flame. In terms of the fact that the jet flame holds the large ratio of flame length to diameter, the new model assumes that all thermal energy is emitted by a line source located inside the jet flame volume. With three typically different shapes to simulate the jet flame shape, a formula is proposed to characterize the profile of the emissive power per line length (EPPLL), by which the line source model can be closed in theory. In comparison with the point source model, the multipoint source model, and the solid flame model, the new model agrees better with the measurement of the heat flux radiated from a small jet flame. It is found that the line source model can well predict the radiant heat flux of both small and large jet flames, yet with the flame shape simulated by the back-to-back cone and the cone–cylinder combined shape, respectively. By parameter sensitivity and uncertainty analysis, the ranking by importance of input parameters is also given for the new model.

Absorbed Radiation Heat Flux Sensors for Orbital Spacecraft. Algorithms for Measurement Data Processing

2021 ◽  
Vol 30 (3) ◽  
pp. 383-403
Author(s):  
A. V. Nenarokomov ◽  
D. L. Reviznikov ◽  
D. A. Neverova ◽  
E. V. Chebakov ◽  
A. V. Morzhukhina ◽  
...  
Keyword(s):  
Heat Flux ◽  
Data Processing ◽  
Measurement Data ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Heat Flux Sensors ◽  
Orbital Spacecraft

Radiation and Convection Heat Transfer in a Porous Bed

1968 ◽  
Vol 90 (1) ◽  
pp. 51-54 ◽  
Author(s):  
W. A. Beckman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Collection Efficiency ◽  
Convection Heat Transfer ◽  
Heat Fluxes ◽  
Fluid Temperature ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Flowing Fluid ◽  
Porous Bed

The one-dimensional steady-state temperature distribution within an isotropic porous bed subjected to a collimated and/or diffuse radiation heat flux and a transparent flowing fluid has been determined by numerical methods. The porous bed was assumed to be nonscattering and to have a constant absorption coefficient. Part of the radiation absorbed by the porous bed is reradiated and the remainder is transferred to the fluid by convection. Due to the assumed finite volumetric heat transfer coefficient, the bed and fluid have different temperatures. A bed with an optical depth of six and with a normal incident collimated radiation heat flux was investigated in detail. The radiation incident on the bed at the fluid exit was assumed to originate from a black surface at the fluid exit temperature. The investigation covered the range of incident diffuse and collimated radiation heat fluxes expected in a nonconcentrating solar energy collector. The results are presented in terms of a bed collection efficiency from which the fluid temperature rise can be calculated.

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.

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