scholarly journals Model tests of fire smoke control effects in highway tunnels

2020 ◽  
Vol 72 (09) ◽  
pp. 781-792
Keyword(s):  
Temperature Distribution ◽  
Flow Pattern ◽  
Similarity Criterion ◽  
Model Tests ◽  
Smoke Control ◽  
Airflow Velocity ◽  
Smoke Flow ◽  
Longitudinal Temperature ◽  
Fire Smoke

In this work, a typical tunnel 150 m in length is selected and modelled at a scale of 1:15 to assess its effects on smoke control. A total of 32 model tests on smoke flow pattern and longitudinal temperature distribution have been carried out based on the Froude similarity criterion. The results show that smoke control is affected by three factors, namely, the longitudinal airflow velocity, number of opened smoke-exhaust dampers, and fire power, out of which the longitudinal airflow velocity has the greatest effect on smoke control.

Study of Fire Smoke Flow of Tunnel at Different Longitudinal Ventilation

2012 ◽  
Vol 226-228 ◽  
pp. 1472-1475
Author(s):  
Pei Pei Yang ◽  
Xiao Lu Shi ◽  
Bi Ming Shi
Keyword(s):  
Flow Resistance ◽  
Reverse Flow ◽  
Ventilation System ◽  
Gas Temperature ◽  
Smoke Control ◽  
Smoke Flow ◽  
Longitudinal Ventilation ◽  
Smoke Spread ◽  
Fire Smoke ◽  
Safety Evacuation

Once the tunnel fires happened, it will cause a major accident. And the smoke control of the runnel is important to fire prevention. A numerical simulation of the fire smoke flow in the tunnel model is presented by using FDS. The influence of different longitudinal ventilation on fire smoke flow of tunnel is obtained. And providing theory basis for tunnel ventilation system design, smoke spread control and safety evacuation. The results shown that in order to avoid reverse-flow and extend the time of smoke at the top of tunnel, the longitudinal speed should be controlled in 3.4 m/s; because of the role of longitudinal ventilation, smoke flow resistance and longitudinal ventilation generated by the effect of smoke flow resistance make the gas temperature first rise and then down.

Study on Fire Smoke Control of Underground Annular Channel

2011 ◽  
Vol 243-249 ◽  
pp. 4887-4890
Author(s):  
Xue Peng Jiang ◽  
Rui Yu Chen ◽  
Zhi Sheng Xu
Keyword(s):  
Annular Channel ◽  
Smoke Control ◽  
Smoke Flow ◽  
Control Schemes ◽  
Fire Smoke

Aiming at the characteristics of many crossroads and large slope of ground exits in Suzhou Underground Annular Channel, fire resistant shutters were advised to set as flexible compartment. The whole channel was divided into 6 smoke control sections by fire resistant shutters and exits and ventilation shafts. The schemes of smoke control and people evacuation were presented. Smoke flow in 6 fire scenes was simulated by FDS 4.0. The results show that fire smoke could be discharged to ground along planned route to ensure the safe evacuation of people and cars, and show that the smoke control schemes are reasonable and effective.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

Experimental study on fire smoke control using water mist curtain in channel

2018 ◽  
Vol 342 ◽  
pp. 231-241 ◽  
Author(s):  
Zhigang Wang ◽  
Xishi Wang ◽  
Yanqing Huang ◽  
Changfa Tao ◽  
Heping Zhang
Keyword(s):  
Experimental Study ◽  
Water Mist ◽  
Smoke Control ◽  
Fire Smoke

Atmospheric dynamics of tidally synchronized extrasolar planets

2008 ◽  
Vol 366 (1884) ◽  
pp. 4477-4488 ◽  
Author(s):  
James Y.-K Cho
Keyword(s):  
Temperature Distribution ◽  
Solar System ◽  
Flow Pattern ◽  
Extrasolar Planets ◽  
Atmospheric Dynamics ◽  
Reliable Interpretation ◽  
Near Future ◽  
Theoretical Issues

Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

scholarly journals Research of Operation Factors of the of Bullerjan Stove in the Program Environmentfor 3D Simulation

2018 ◽  
Vol 7 (4.3) ◽  
pp. 350
Author(s):  
A. Kagramanyan ◽  
A. Onishchenko ◽  
J. Babichenko ◽  
A. Podoprigora
Keyword(s):  
Temperature Distribution ◽  
Heat Pipe ◽  
3D Modeling ◽  
Thermal Power ◽  
Flow Simulation ◽  
Heat Pipes ◽  
3D Simulation ◽  
Heat Output ◽  
Thermophysical Characteristics ◽  
Airflow Velocity

The article is devoted to the calculation of the thermal power of the Bullerjan stove according to a preconstructed model, which is realized in the 3D modeling environment of SolidWorks 2016. The thermophysical characteristics of the processes passing through the heat pipes of the Bullerjan stove were studied in detail. In the course of the work, the values of airflow velocity and temperature distribution, the temperature distribution of a solid, the surface of the heat pipe, that in the end allowed us to obtain the values of the heat output of the oven. The obtained data made it possible to determine the value of the heat output of the oven on the mode of smoldering wood and on the mode of flaming burning. The thermal power of a Bullerjan stove and in particular, its flow simulation module for modeling the flow of liquids and gases were obtained. 

Oil Skimming Efficiency of the SOS: Scaling From GeoSim Model Tests to Full Scale Prototype Operations

2012 ◽  
Author(s):  
Günther F. Clauss ◽  
Sascha Kosleck ◽  
Florian Sprenger ◽  
Laura Grüter
Keyword(s):  
Flow Pattern ◽  
Oil Recovery ◽  
Open Water ◽  
Model Tests ◽  
Full Scale ◽  
Polluted Water ◽  
Water Separation ◽  
Weathering Processes ◽  
River Elbe ◽  
Hydrodynamic Effects

The severe ecological and economical aftermath of the 2010 ‘Deepwater Horizon’ catastrophe in the Gulf of Mexico clearly shows the insufficiency of current oil recovery systems which cannot operate in wave heights above 1.5m. To prevent emulsification and weathering processes, it is necessary to skim the oil film off the sea surface shortly after the accident. The autonomous SOS (Sea State-independent Oil Skimming System) developed within the framework of the research project SOS3 features high transit velocities, the capability of operating in rough seas and a massive intake of oil polluted water — and is therefore a unique technology. The oil water separation process of the SOS is purely based on hydrodynamic principles involving vortex evolution and a special flow pattern inside the internal moon pool. These requirements for efficient oil skimming operations depend on various hydrodynamic effects that would imply model testing in compliance with Froude’s and Reynolds’ law simultaneously — a physically impossible condition. Therefore GeoSim model tests with the SOS at model scales of 1:16, 1:25 and 1:36 are conducted with discrete particles of the correct density substituting the oil phase. The tendencies in flow pattern evolution and oil skimming efficiency are compared and extrapolated to full scale. Results from open water tests with the prototype of the SOS in the mouth of river Elbe serve for validation of the extrapolated results.

scholarly journals A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1411 ◽  
Author(s):  
Peng Zhao ◽  
Zhongyuan Yuan ◽  
Yanping Yuan ◽  
Nanyang Yu ◽  
Tao Yu
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Empirical Equation ◽  
Ventilation System ◽  
Volumetric Flow Rate ◽  
Subway Tunnel ◽  
Smoke Control ◽  
Long Distance ◽  
Tunnel Fire ◽  
Ceiling Temperature

Smoke control is a crucial issue in a long-distance subway tunnel fire, and a two-point extraction ventilation system is an effective way to solve this problem, due to the characteristics of controlling the smoke in a limited area and removing high-temperature and toxic smoke in time. In this study, the ceiling temperature distribution and the critical exhaust volumetric flow rate to control the smoke in the zone between two extraction vents were investigated in a long-distance subway tunnel fire with a two-point extraction ventilation system. Experiments were carried out in a 1/20 reduced-scale tunnel model based on Froude modeling. Factors, including the heat release rate (HRR), the extraction vent length, the internal distance between two extraction vents and exhaust volumetric flow rate, were studied. Smoke temperature below the ceiling, exhaust volumetric flow rate and smoke spreading configurations were measured. The ceiling temperature distribution was analyzed. Meanwhile, an empirical equation was developed to predict the critical exhaust volumetric flow rate based on the one-dimensional theory, experimental phenomenon and the analysis of forces acting at the smoke underneath the extraction vent. The coefficients in the empirical equation were determined by experimental data. Compared with the experimental results, the developed empirical equation can predict the critical exhaust volumetric flow rate well. Research outcomes in this study will be beneficial to the design and application of two-point extraction ventilation system for a long-distance subway tunnel fire.

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