scholarly journals Effect of the Cone Heater Scale Compliant with the ISO 5660 Standard on Spatial Uniformity of Radiant Heat Flux

2020 ◽  
Vol 34 (5) ◽  
pp. 27-33
Author(s):  
Sanghoon Ryu ◽  
Sun-Yeo Mun ◽  
Cheol-Hong Hwang
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Cone Calorimeter ◽  
Large Deviation ◽  
Mass Loss Rate ◽  
Radiant Heat ◽  
Radiant Heat Flux ◽  
Spatial Uniformity ◽  
Measurement Results ◽  
Physical Quantities

Physical quantities such as mass loss rate, heat release rate, and total heat release are often measured through a cone calorimeter (a representative bench-scale apparatus) and are primarily considered as values per unit area. Hence, the uniformity of radiant heat flux supplied by the cone heater to the specimen is very important with respect to the measurement results’ validity. In this study, on the basis of the ISO 5660 standard, the uniformity of radiant heat flux at the specimen surface was evaluated for the cone heaters used with the cone calorimeter. It is observed that a normal cone heater (NCH) compliant with the ISO 5660-1 standard satisfies the requirement of uniformity within a range of ± 2% in the central 5 cm × 5 cm area, but it has a large deviation of approximately 13% at the position corresponding to the edge of the specimen. In addition, the duration of NCH usage does not significantly affect the distribution of radiant heat flux. Furthermore, it is observed that a large cone heater compliant with the ISO/TC 5660-4 standard can supply moderately-uniform radiant heat flux over the entire surface area (10 cm × 10 cm) of the specimen.

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.

Bench-scale experimental study on the fire behavior of electric cable arrays by considering different layouts

2021 ◽  
pp. 073490412110432
Author(s):  
Zhou Cai ◽  
Xiao Chen ◽  
Jiaqing Zhang ◽  
Shouxiang Lu
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Behavior ◽  
Radiant Heat ◽  
Radiant Heat Flux ◽  
Total Heat Release ◽  
Electric Cable ◽  
Peak Heat Release Rate

The effect of different cable layouts on the fire behavior of electric cable arrays was experimentally studied. The influence of external heat flux on cable fire characteristics was investigated. Several parameters for electrical cables such as the post-burning morphology, ignition time, heat release rate, peak heat release rate and total heat release were obtained. The results show that cable layouts could affect cable charring degrees according to the post-burning morphology. A linear relationship was found in the transformed form of time to ignition and radiant heat flux, and the critical radiant heat flux value for the single cable array appeared smaller than that for the other two layouts. The peak heat release rate for Cables A–D with the single array presents the increasing trend with an increase in radiant heat flux, while the two parallel and intersectional cable arrays present the different trends. Moreover, the total heat release values of Cables A–D in the different cable layouts were analyzed. This work provides the basic data and preliminary investigation to fire engineering of cable arrays with the different layouts.

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.

Radiant heat flux modelling for wildfires

2020 ◽  
Vol 175 ◽  
pp. 62-80 ◽  
Author(s):  
James E. Hilton ◽  
Justin E. Leonard ◽  
Raphaele Blanchi ◽  
Glenn J. Newnham ◽  
Kimberley Opie ◽  
...  
Keyword(s):  
Heat Flux ◽  
Radiant Heat ◽  
Radiant Heat Flux

Study of thermomechanical coupling in carbon fibers woven‐ply reinforced thermoplastic laminates: Tensile behavior under radiant heat flux

2020 ◽  
Vol 41 (9) ◽  
pp. 3552-3563
Author(s):  
Yann Carpier ◽  
Benoit Vieille ◽  
Alexis Coppalle ◽  
Fabrice Barbe
Keyword(s):  
Heat Flux ◽  
Carbon Fibers ◽  
Radiant Heat ◽  
Tensile Behavior ◽  
Thermomechanical Coupling ◽  
Radiant Heat Flux

Radiant heat flux to external surfaces from escaping and extrusive flashover flames

2003 ◽  
Vol 217 (2) ◽  
pp. 247-256 ◽  
Author(s):  
A Chen ◽  
J Francis
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Current Practice ◽  
Radiant Heat ◽  
Vertical Surface ◽  
Radiant Heat Flux ◽  
Hot Gas

Current practice when predicting safe separation distances between buildings is to assess the radiant hazard posed by flames and hot gas visible across the vent. The vent is treated as a radiating vertical surface with a representative temperature. A method is proposed for calculating the radiant heat flux to external surfaces from hot gas and extrusive flame emerging from a vent in a compartment wall containing post-flashover fire. An experimental study has been made to examine the validity of the method for extrusive flames unaffected by wind.

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