scholarly journals Study on Underground Utility Tunnel Fire Characteristics under Sealing and Ventilation Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Hongtao Zhang ◽  
Yufei Zhao
Keyword(s):  
Safety Evaluation ◽  
Maximum Temperature ◽  
Physical Parameters ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Ceiling Temperature ◽  
Ventilation Modes ◽  
Utility Tunnel ◽  
Fire Characteristics ◽  
Ventilation Conditions

With the development of the underground utility tunnel in China, the safety evaluation during facility operation inside tunnels is increasingly important after construction. In contrast to fixed fire source in the traffic tunnel, the fire characteristics of the electric cable compartment of the utility tunnel with different ventilation modes are studied. Firstly, the thermal physical parameters of cable material are determined by experiment and numerical simulation. Different fire sealing and ventilation conditions are established according to the practical utility tunnel engineering in FDS. The maximum temperature and smoke gas concentrations are obtained, as well as the heat release rate. The results show that the utility tunnel fire has obvious differences compared with road tunnel fire, where the maximum ceiling temperature and the distributions of smoke is related to fire sealing and ventilation mode. Some suggestions related to evaluation and firefighting are provided for practical purposes.

Study on Fire Design in Xuefengshan Highway Tunnel

2012 ◽  
Vol 170-173 ◽  
pp. 1652-1655
Author(s):  
Yong Lin An
Keyword(s):  
Longitudinal Velocity ◽  
Safety Evaluation ◽  
Fire Risk ◽  
Fundamental Principle ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Highway Tunnel ◽  
Radiation Theory ◽  
Evacuation Safety ◽  
Fire Spreading

The fundamental principle for tunnel fire fighting design is to ensure the safety of people’s escape from tunnel fire. Therefore the computer model Tunev (tunnel evacuation) for the people's safe escape was developed. In order to evaluate evacuation safety, Fire risk times Tfire was firstly gotten through simulations of a middle size fire, whose heat release rate (HRR) was 20MW, with a longitudinal velocity of 3m/s suggested in Code for Design of Road Tunnel of 2004, and evacuation times Tevacuate was calculated by an empirical formula in the Togawa evacuation model. Meanwhile, fire spreading to other cars was analyzed by radiation theory. Finally, cross passage spacing was optimized in a method of evacuation safety evaluation. Results are given as follows: Tfire equal to 290s are bigger than Tevacuate equal to 267s, the smallest igniting spacing between cars is 13m, and the optimized cross passage spacing is 290m. All those are shown that: evacuation is safe, and to some extent code is testified correct.

Numerical simulation of fire in road tunnel. Selection of calculation grid

2021 ◽  
pp. 47-54
Author(s):  
И.А. Болодьян ◽  
С.В. Пузач ◽  
А.С. Барановский
Keyword(s):  
Field Tests ◽  
Field Method ◽  
Research Field ◽  
Computational Grids ◽  
Maximum Temperature ◽  
Road Tunnel ◽  
Road Tunnels ◽  
The Masses ◽  
Control Volumes ◽  
Calculation Grid

Рассматривается вопрос выбора расчетной сетки при моделировании пожара в тоннеле с помощью полевого метода и проводится оценка возможного влияния размеров ячеек сетки, а также граничного условия постоянства давления на результаты расчета. Выполнено моделирование пожара для четырех размеров расчетной сетки. Обоснована возможность применения наиболее грубой из используемых сеток с точки зрения инженерных расчетов, в том числе с оговоркой относительно постановки граничного условия. The issue of fire safety of road tunnels is currently an urgent task. Road tunnels are usually not standard typical facilities, but the unique structures. Therefore, it is necessary to study the influence of various parameters on the development of fire in order to take into account the characteristics of a particular object and make decisions on its effective fire protection. Implementation of field tests in this case is expensive and time-consuming. In this regard, numerical modeling is one of the most effective methods of such research. Field models are the most common and currently used for numerical calculations. These models are based on the numerical solution of the system of conservation equations for small control volumes of the calculation grid. This paper examines the issues of selection the calculation grid when modeling a fire in tunnels using the field method is considered and the possible influence of the size of the grid cells is estimated. The mathematical model used in this work is based on a set of differential equations of hydrodynamics, heat transfer, as well as the equation of conservation of the masses of components. Four computational grids were selected for a horizontal (without slope) model tunnel to determine the optimal cell size. As a result of conducted calculations it was established the following: the size of calculated grid is not fundamental for the initial stage of the fire; the use of smaller grid may be preferable at further development of fire, accompanied by increase of combustion capacity to the maximum; the maximum temperature values, especially in the far sections, are obtained on the coarsest grid. The use of such a grid for estimated engineering calculations can be allowed.

COMPARISON BETWEEN LONGITUDINAL VENTILATION SYSTEM AND POINT EXTRACTION SYSTEM IN ROAD TUNNEL FIRE SAFETY

2021 ◽  
Vol 77 (1) ◽  
pp. 41-59
Author(s):  
Ti-Sheng HUANG ◽  
Nobuyoshi KAWABATA ◽  
Miho SEIKE ◽  
Masato HASEGAWA ◽  
Futoshi TANAKA ◽  
...  
Keyword(s):  
Fire Safety ◽  
Ventilation System ◽  
Extraction System ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Longitudinal Ventilation

scholarly journals Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years

2011 ◽  
Vol 7 (4) ◽  
pp. 1337-1349 ◽  
Author(s):  
G. M. Ganssen ◽  
F. J. C. Peeters ◽  
B. Metcalfe ◽  
P. Anand ◽  
S. J. A. Jung ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Isotope Composition ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Maximum Temperature ◽  
Physical Parameters ◽  
Seasonal Temperature ◽  
Mean Values ◽  
The Past ◽  
Temperature Ranges

Abstract. The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface-dwelling species Globigerinoides ruber and Globigerina bulloides from sediment cores in the Western Arabian Sea off Somalia, inferred as indicators of past seasonal ranges in temperature. Combining the δ18O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyr the seasonal temperature range has fluctuated from its present value of 16 °C to mean values of 13 °C and 11 °C for the Holocene and LGM, respectively. The data for the LGM suggest that the maximum temperature was lower, whilst minimum temperature remained approximately constant. The rather minor variability in lowest summer temperatures during the LGM suggests roughly constant summer monsoon intensity, while upwelling-induced productivity was lowered.

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