Investigations of a convective column above the surface forest fire

Simulation Approach in Forecasting Radioactive Situation in Case of Forest Fires in Radioactive Contaminated Zones

Medical Radiology and radiation safety ◽

10.12737/article_5c0c1209d926d4.00249293 ◽

2018 ◽

Vol 63 (6) ◽

pp. 21-26

Author(s):

Е. Береснева ◽

E Beresneva ◽

Б. Галушкин ◽

B. Galushkin ◽

С. Горбунов ◽

...

Keyword(s):

Atmospheric Turbulence ◽

Forest Fire ◽

Radioactive Contamination ◽

Forest Fires ◽

Large Scale ◽

The Body ◽

Radioactive Impurity ◽

Molecular Kinetic Theory ◽

Convective Column ◽

Random Nature

Purpose: The accident at the Chernobyl NPP caused radioactive contamination of large areas, including forestry. For the last decades forest fires in the RF tend to increase and, more alarmingly, their burnt-out area significantly expands. So, the risk of large-scale forest fires in the area of radioactive contamination increases. Effectiveness of the measures for radiation protection of population and personnel involved in fire response is directly related to existence of valid methods of radiation situation prognostication. The work is aimed to develop a method of prognostication of radiation situation at forest fire in the area of radioactive contamination, taking into account random nature of atmospheric turbulence and a convective column over the body of fire, and to estimate validity of this method. Material and methods: Methods of simulation modeling of mass transfer processes in the atmosphere (method of Bird) based on the molecular-kinetic theory and gas-dynamic theory were used when developing the prognostication method. Results: The simulation model of formation, spreading and fall-out of radioactive cloud taking into account random nature of atmospheric turbulence and presence of a convective column over the body of fire has been developed; the method of prognostication of radiation situation at forest fire in the area of radioactive contamination has been developed and verified based on data of European experiment E1. The relative error of received values in the control points of radiation situation parameters based on data of experiment E1 did not exceed 0.25. Conclusion: Use of modified method of Bird allowed developing 3D dynamic model of spreading of radioactive impurity into atmosphere at convective rising by heated air flow from underlying surface. This model takes into account random nature of atmospheric turbulence and presence of a convective column over the body of fire which significantly increases accuracy of the method of radiation situation prognostication.

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Forest fire

AccessScience ◽

10.1036/1097-8542.268900 ◽

2015 ◽

Keyword(s):

Forest Fire

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Numerical simulation of the tree higro-thermal response in forest fire environment

WEENTECH Proceedings in Energy ◽

10.32438/wpe.0220 ◽

2020 ◽

pp. 57-65

Author(s):

Eusébio Conceiçã ◽

João Gomes ◽

Maria Manuela Lúcio ◽

Jorge Raposo ◽

Domingos Xavier Viegas ◽

...

Keyword(s):

Forest Fire ◽

Numerical Study ◽

Thermal Response ◽

View Factor ◽

Tree Model ◽

Pine Tree ◽

Surface Temperatures ◽

Fire Environment ◽

Fire Front ◽

Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

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