Influence of the radiative heat exchanges between the fire front and vehicle passengers in a road

2014 ◽  
pp. 316-321
Author(s):  
Eusébio Z. E. Conceição ◽  
Manuel C. Gameiro Silva ◽  
Domingos X. Viegas
Keyword(s):  
Radiative Heat ◽  
Fire Front ◽  
Heat Exchanges

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

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.

A generalized model of human body radiative heat exchanges for optimal design of indoor thermal comfort conditions

Solar Energy ◽  
2018 ◽  
Vol 176 ◽  
pp. 556-571 ◽  
Author(s):  
Concettina Marino ◽  
Antonino Nucara ◽  
Giorgia Peri ◽  
Matilde Pietrafesa ◽  
Gianfranco Rizzo
Keyword(s):  
Optimal Design ◽  
Thermal Comfort ◽  
Human Body ◽  
Radiative Heat ◽  
Generalized Model ◽  
Indoor Thermal Comfort ◽  
Heat Exchanges

scholarly journals Thermotronics: Towards Nanocircuits to Manage Radiative Heat Flux

2017 ◽  
Vol 72 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Philippe Ben-Abdallah ◽  
Svend-Age Biehs
Keyword(s):  
Heat Flux ◽  
Radiative Heat ◽  
Daily Life ◽  
Radiative Heat Flux ◽  
Far Field ◽  
Electric Currents ◽  
Heat Exchanges ◽  
Complex Architecture

AbstractThe control of electric currents in solids is at the origin of the modern electronics revolution that has driven our daily life since the second half of 20th century. Surprisingly, to date, there is no thermal analogue for a control of heat flux. Here, we summarise the very last developments carried out in this direction to control heat exchanges by radiation both in near and far-field in complex architecture networks.

Comparatives study of radiative heat exchanges between fire front from fireman and pine tree in warm thermal conditions

2020 ◽  
pp. 39-49
Author(s):  
Eusébio Conceição ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Viegas ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Human Body ◽  
Thermal Conditions ◽  
Mean Radiant Temperature ◽  
Human Body Model ◽  
Tree Model ◽  
Pine Tree ◽  
Fire Front ◽  
Radiant Temperature ◽  
Heat Exchanges

This work presents the development of a numerical design in forest fire environments. A comparison between a tree body and a human body (fireman) thermal response systems is made. The three-dimensional pine tree model is constituted by trunk, branches and leaves represented by cylindrical elements. The human body model is divided into 35 elements and considers its thermoregulation. In both systems, special attention is required with conduction, convection, evaporation and radiation. There are also considered the heat exchanges by radiation between the fire front and both bodies. A vertical fire front, with 2 m of height and 20 m of length, was considered. The air temperature, air velocity, air relative humidity and mean radiant temperature are used. Two cases were studied: a pine tree and a fireman placed nearby the fire front. The results of the flame mean radiant temperature, temperature of the bodies surfaces and view factors are obtained. The results show that the fireman is most exposed than the pine tree to the fire front. Due to the human thermoregulatory and clothing systems, the fireman has a skin surface temperature much lower than the surface temperature in the trunks, branches and leaves of the tree. The evaporation in the tree is not sufficient to control the temperature.

scholarly journals Narrow-to-Broadband Conversion for Albedo Estimation on Urban Surfaces by UAV-Based Multispectral Camera

2020 ◽  
Vol 12 (14) ◽  
pp. 2214
Author(s):  
Xi Xu ◽  
Takashi Asawa ◽  
Hideki Kobayashi
Keyword(s):  
Surface Albedo ◽  
Surface Energy Balance ◽  
Radiative Heat ◽  
High Spatial Resolution ◽  
Urban Surface ◽  
Surface Material ◽  
Aerial Vehicle ◽  
Multispectral Remote Sensing ◽  
Urban Complex ◽  
Heat Exchanges

Urban surface albedo is important for investigating urban surface–atmosphere radiative heat exchanges. For modeling surface energy balance (SEB) at local and neighborhood scales, ground or unmanned aerial vehicle (UAV)-based multispectral remote sensing (RS) can be used to obtain high-spatial-resolution multispectral information for both horizontal and vertical urban surfaces. The existing narrow-to-broadband (NTB) conversion models, developed for satellite/high-altitude observation and large homogeneous rural/vegetated/snow zones, may not be suitable for downscaling to the local and neighborhood scales or the urban complex texture. We developed three NTB models following published methodologies for three common UAV-based multispectral cameras according to Sample_D, a sample group of extensive spectral albedos of artificial urban surfaces, and evaluated their performance and sensitivities to solar conditions and surface material class. The proposed models were validated with independent samples (Sample_V). A model considering albedo physics was improved by multiplying different variables with respect to the camera (termed as “Model_phy_reg”), which initially proved to be the most accurate with a root mean square error of up to 0.02 for Sample_D and approximately 0.029 for Sample_V, meeting the required accuracy of total shortwave albedo for SEB modeling. The accuracy of Model_phy_reg was not much prone to the solar conditions.

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