Behavior of the Spruce and Birch Wood from the Fire Safety Point of View

2013 ◽  
Vol 842 ◽  
pp. 725-728 ◽  
Author(s):  
Petr Kučera ◽  
Antonín Lokaj ◽  
Vladimír Vlček
Keyword(s):  
Heat Flux ◽  
Carbon Monoxide ◽  
Flux Density ◽  
Fire Safety ◽  
Maximum Concentration ◽  
Heat Flux Density ◽  
Point Of View ◽  
Birch Wood ◽  
Char Layer ◽  
Charring Rate

In the presented paper is comprehensively assessed the behavior of spruce and birch wood during fire. Samples were loaded by heat flux of 20, 35 and 50 kW/m2in apparatus according to ISO 5657. The duration of the test was up to 30 min. The behavior of the samples was evaluated on the basis of charring rate and concentrations of carbon monoxide in smoke. Charring rate was rising with increasing heat flux density and decreasing linearly with increasing density of the samples. The maximum concentration of CO in the smoke for spruce and birch wood was observed just before the end of the test, during the phase of char layer burning.

THERMAL BEHAVIOR AND IGNITION OF HIGH-ENERGY MATERIALS CONTAINING B, ALB2, AND TIB2

2020 ◽  
Author(s):  
A. G. Korotkikh ◽  
◽  
V. A. Arkhipov ◽  
I. V. Sorokin ◽  
E. A. Selikhova ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Flux Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Heat Flux Density ◽  
Ignition Delay Time ◽  
High Energy ◽  
Energy Materials ◽  
High Energy Materials

The paper presents the results of ignition and thermal behavior for samples of high-energy materials (HEM) based on ammonium perchlorate (AP) and ammonium nitrate (AN), active binder and powders of Al, B, AlB2, and TiB2. A CO2 laser with a heat flux density range of 90-200 W/cm2 was used for studies of ignition. The activation energy and characteristics of ignition for the HEM samples were determined. Also, the ignition delay time and the surface temperature of the reaction layer during the heating and ignition for the HEM samples were determined. It was found that the complete replacement of micron-sized aluminum powder by amorphous boron in a HEM sample leads to a considerable decrease in the ignition delay time by a factor of 2.2-2.8 at the same heat flux density due to high chemical activity and the difference in the oxidation mechanisms of boron particles. The use of aluminum diboride in a HEM sample allows one to reduce the ignition delay time of a HEM sample by a factor of 1.7-2.2. The quasi-stationary ignition temperature is the same for the AlB2-based and AlB12-based HEM samples.

A thermoelectric device for ophthalmic heat flux density measurements: results of piloting in healthy individuals

2019 ◽  
Vol 80 (3) ◽  
pp. 45-51
Author(s):  
L. Anatychuk ◽  
N. Pasyechnikova ◽  
V. Naumenko ◽  
O. Zadorozhnyy ◽  
R. Kobylianskyi ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flux Density ◽  
Heat Flux Density ◽  
Thermoelectric Device ◽  
Healthy Individuals ◽  
Density Measurements

scholarly journals Expansion of the Range of Refrigeration of the Surface Heat Flow Unit Under Conductive Energy Produce

2018 ◽  
pp. 27-32
Author(s):  
S. Kovtun
Keyword(s):  
Heat Flux ◽  
Heat Flow ◽  
Flux Density ◽  
Heat Flux Density ◽  
Dynamic Range ◽  
Density Measurement ◽  
Lower Boundary ◽  
Surface Heat ◽  
Total Uncertainty ◽  
Unit Of Measurement

The article presents the results of investigations of factors that influence the accuracy of reproduction of the unit of measurement of the surface density of the heat flow by conductivity. Components of the uncertainty of the surface heat flux density measurement were analyzed using the Ishikawa cause-and-effect diagram, as shown in Fig. 1 The mathematical model of the method of reproduction of the unit of measurement was obtained, which takes into account the influence of the sources of uncertainty by making the corresponding corrections. The possibility of extending the lower boundary of the dynamic range by the correction of the factors having the greatest influence is substantiated. The rationale is based on the estimation of the uncertainty of the individual components, which, in the course of the correction of their impact, should not exceed the values (achieved to date). As an example, the calculation of the total uncertainty in the reproduction of the heat flux density of 20 W·m-2 is given. Table 1 contains all data important for the uncertainty analysis such as input quantities, their estimated values as well as the associated sensitivity coefficients and the variances determined.

Heat Removal and Thermal Stabilization of High-temperature Surfaces by a Dispersed Coolant Flow

Vestnik MEI ◽  
2021 ◽  
pp. 19-26
Author(s):  
Valentin S. Shteling ◽  
◽  
Vladimir V. Ilyin ◽  
Aleksandr T. Komov ◽  
Petr P. Shcherbakov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flux Density ◽  
Flow Rate ◽  
Heat Flux Density ◽  
Coolant Flow ◽  
Transfer Coefficients ◽  
Stationary Heat ◽  
Heat Transfer Coefficients ◽  
Stationary Heat Transfer

The effectiveness of stabilizing the surface temperature by a dispersed coolant flow is experimentally studied on a bench simulating energy intensive elements of thermonuclear installations A test section in which the maximum heat flux density can be obtained when being subjected to high-frequency heating was developed, manufactured, and assembled. The test section was heated using a VCh-60AV HF generator with a frequency of not lower than 30 kHz. A hydraulic nozzle with a conical insert was used as the dispersing device. Techniques for carrying out an experiment on studying a stationary heat transfer regime and for calculating thermophysical quantities were developed. The experimental data were obtained in the stationary heat transfer regime with the following range of coolant operating parameters: water pressure equal to 0.38 MPa, water mass flow rate equal to 5.35 ml/s, and induction heating power equal to 6--19 kW. Based on the data obtained, the removed heat flux density and the heat transfer coefficients were calculated for each stationary heat transfer regime. The dependences of the heat transfer coefficient on the removed heat flux density and of the removed heat flux density on the temperature difference have been obtained. High values of heat transfer coefficients and heat flux density at a relatively low coolant flow rate were achieved in the experiments.

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