scholarly journals Effect Of External Radiant Heat Flux On Upward Fire Spread: Measurements On Plywood And Numerical Predictions

1994 ◽  
Vol 4 ◽  
pp. 421-432 ◽  
Author(s):  
M. Delichatsios ◽  
Peter Wu ◽  
M. Delichatsios ◽  
G. Lougheed ◽  
G. Crampton ◽  
...  
Keyword(s):  
Heat Flux ◽  
Radiant Heat ◽  
Fire Spread ◽  
Radiant Heat Flux ◽  
Numerical Predictions

scholarly journals The Effect of Environmental Moisture Conditions on the Calculated Incident Radiant Heat Flux by Plate Thermometers

2020 ◽  
Vol 6 (4) ◽  
pp. 102
Author(s):  
Lahiru Jayathunga-Mudiyanselage ◽  
Haejun Park ◽  
Virginia Charter ◽  
Rob Agnew
Keyword(s):  
Heat Flux ◽  
Moisture Content ◽  
Radiant Heat ◽  
Fire Spread ◽  
Radiant Heat Flux ◽  
Absorbed Energy ◽  
Wood Moisture ◽  
Moisture Equivalent ◽  
Two Phases ◽  
Moisture Conditions

This study investigates the effect of environmental moisture conditions on the calculated incident radiant heat flux (irradiance) by plate thermometers (PT). Alterations were made to the moisture content of the PT insulation layers to achieve these conditions. Irradiance was calculated using a pre-determined equation based on fully insulated conditions and validated using a Schmidt-Boelter radiometer. The study consisted of two phases; (i) investigating the effect of preheating PT to the accurate irradiance, (ii) investigating the effect of moisture in the PT on the measurement of irradiance. Calculated irradiance agreed with measured for preheated PT, but not with unheated PT. Four representative moisture conditions were identified for phase two, whereby samples were equilibrated at 0, 45, 65, and 98 wood moisture equivalent (%WME). No noticeable difference identified between measured and calculated irradiance was detected within 0–65%WME. PT with 98%WME showed a difference between the irradiance as the moisture inside the PT insulation absorbed energy from the PT to vaporize. Therefore, using preheated PT with any %WME under 65 is recommended to obtain accurate enough irradiance measurements. The result can use to improve determining the fire spread mechanisms and accurate measurements of irradiance in outdoor fires such as informal settlements fires.

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.

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

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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