scholarly journals VERIFICATION AND VALIDATION OF NUMERICAL MODEL OF FIRE AND SMOKE DEVELOPMENT IN RAILWAY TUNNEL

2016 ◽  
Vol 56 (6) ◽  
pp. 432-439 ◽  
Author(s):  
Kamila Cabová ◽  
František Wald
Keyword(s):  
Numerical Model ◽  
Calculated Data ◽  
Mesh Size ◽  
Verification And Validation ◽  
Numerical Code ◽  
Gas Temperature ◽  
Road Tunnel ◽  
Railway Tunnel ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator

<p>The paper describes verification and validation of numerical model of fire and smoke development in a railway tunnel carried out in numerical code Fire Dynamic Simulator. To evaluate a correctness of numerical solution of the model with respect to the mathematical model, results are compared with solution executed in numerical code SmartFire. Influence of mesh size on results of gas temperature in vicinity to the fire source is studied. Validation of a level of agreement between the numerical model and a physical model is performed by comparison of calculated data with data measured during the fire test in road tunnel Valík located in the Czech Republic.</p>

scholarly journals VERIFICATION OF NUMERICAL MODEL OF FIRE AND SMOKE DEVELOPMENT IN RAILWAY TUNNEL

2016 ◽  
Author(s):  
Kamila Horová ◽  
František Wald ◽  
Jiří Apeltauer
Keyword(s):  
Numerical Model ◽  
Prediction Models ◽  
Numerical Models ◽  
Fire Spread ◽  
Complex Problem ◽  
Gas Temperature ◽  
Tunnel Length ◽  
Fire Dynamics ◽  
Railway Tunnel ◽  
Mesh Density

Simulation of fire spread and development of toxic gases during a fire accident in a railway tunnel allows prepare and validate models of safe evacuation of people. Highly complex problem of fire dynamics in a tunnel can be solved by the aid of numerical models based on CFD method. In order to check the quality of prediction models the procedure of verification is used. A relatively simple model of a single track railway tunnel is solved in two independent codes - FDS and Smart Fire. Accuracy of the model prediction is verified by the aid of gas temperature resolution along the tunnel length. To estimate an error based on different mesh resolutions of numerical model, calculation of the same model is carried out using different mesh density.

scholarly journals Verification and Validation of Fire Dynamic Simulator for Enclosed Car Park

2017 ◽  
Vol 7 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Ahmad Faiz Tharima ◽  
◽  
Md Mujibur Rahman ◽  
Mohd Zamri Yusoff
Keyword(s):  
Verification And Validation ◽  
Dynamic Simulator ◽  
Car Park ◽  
Fire Dynamic Simulator

Effects of Exit Vent Location on Fire Room Conditions During PPV

2008 ◽  
Author(s):  
Colin M. Beal ◽  
Ofodike A. Ezekoye
Keyword(s):  
Positive Pressure ◽  
Computational Simulations ◽  
Cold Flow ◽  
Flow Simulations ◽  
Advantages And Disadvantages ◽  
Experimental Compartment ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
Hot Products ◽  
Vent Location

Positive Pressure Ventilation (PPV) is a widely used fire fighting tactic in which a fan is used to push hot products of fire out of a burning structure. There is a recent body of research that has been conducted regarding the advantages and disadvantages of PPV. Studies of PPV most commonly use full scale experimental fires and/or computational simulations to evaluate its effectiveness. This paper presents computational simulations that have been conducted using Fire Dynamic Simulator (FDS) version 5 to evaluate the effects of exit vent location on resulting fire room conditions during the application of PPV to a ventilation constrained fire. The simulations use a simple one room structure with an adjacent hallway. We are simulating this geometry because we are in the process of designing and constructing a similar experimental compartment. Cold flow simulations are first conducted to understand how much the presence of the fire heat release affects the flow patterns. Then, two simulations which employ PPV with different exit vent locations are compared. The differences between the two simulations are detailed and a physical explanation for the differences is presented.

scholarly journals Numerical Calculations of WR-40 Boiler Based on its Zero-Dimensional Model

2014 ◽  
Vol 35 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Bartłomiej Hernik
Keyword(s):  
Numerical Model ◽  
Flue Gases ◽  
Balance Model ◽  
Furnace Chamber ◽  
Gas Temperature ◽  
Cfd Modelling ◽  
Boiler Furnace ◽  
Average Temperature ◽  
Furnace Outlet ◽  
Dissipation Model

Abstract Generally, the temperature of flue gases at the furnace outlet is not measured. Therefore, a special computation procedure is needed to determine it. This paper presents a method for coordination of the numerical model of a pulverised fuel boiler furnace chamber with the measuring data in a situation when CFD calculations are made in regard to the furnace only. This paper recommends the use of the classical 0-dimensional balance model of a boiler, based on the use of measuring data. The average temperature of flue gases at the furnace outlet tk" obtained using the model may be considered as highly reliable. The numerical model has to show the same value of tk" . This paper presents calculations for WR-40 boiler. The CFD model was matched to the 0-dimensional tk" value by means of a selection of the furnace wall emissivity. As a result of CFD modelling, the flue gas temperature and the concentration of CO, CO2, O2 and NOx were obtained at the furnace chamber outlet. The results of numerical modelling of boiler combustion based on volumetric reactions and using the Finite-Rate/Eddy-Dissipation Model are presented.

Safety Aspects of the Lötschberg Railway Tunnel & Mont-Blanc Road Tunnel

2017 ◽  
pp. 3-8
Author(s):  
F. Vuilleumier ◽  
A. Weatherill ◽  
Y. Trottet ◽  
B. Crausaz
Keyword(s):  
Road Tunnel ◽  
Railway Tunnel ◽  
Safety Aspects

scholarly journals Heat Transfer Modelling and Simulation of a 120 mm Smoothbore Gun Barrel During Interior Ballistics

2022 ◽  
Vol 72 (1) ◽  
pp. 30-39
Author(s):  
Cigdem Susantez ◽  
Aldelio Bueno Caldeira
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Gas Temperature ◽  
Interior Ballistics ◽  
Heat Transfer Phenomenon

Understanding the heat transfer phenomenon during interior ballistics and consequently presenting a realistic model is very important to predict the temperature distribution inside the cannon barrel, which influences the gun wear and the cook-off. The objective of this work is to present a new detailed numerical model for the prediction of thermal behaviour of a cannon barrel by combining PRODAS interior ballistics simulation with COMSOL simulation. In this study, a numerical model has been proposed for the heating behaviour of a 120 mm smoothbore cannon barrel, taking into account the combustion equation of the JA-2 propellant. Temperature dependent thermophysical properties of product gases were used for the calculation of the convective heat transfer coefficient inside the barrel. Projectile position, velocity of the projectile, gas temperature inside the barrel, volume behind the projectile and mass fraction during interior ballistics have been obtained by PRODAS software and used in the numerical model performed by COMSOL multiphysics finite element modelling and simulation software. Temperature simulations show that maximum wall temperature inside the cannon barrel is observed after 3 ms from fire, when maximum value of the convective heat transfer coefficient inside the barrel is observed. The results reveal that the convective heat transfer coefficient of burned gases inside the gun has major effect than the burned gas temperature on the heat transfer phenomenon.

scholarly journals Q-Learning Neural Controller for Steam Generator Station in Micro Cogeneration Systems

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5334
Author(s):  
Krzysztof Lalik ◽  
Mateusz Kozek ◽  
Szymon Podlasek ◽  
Rafał Figaj ◽  
Paweł Gut
Keyword(s):  
Numerical Model ◽  
Control Systems ◽  
Steam Generator ◽  
Full Range ◽  
Combustion Process ◽  
Liquid Fuels ◽  
Control Algorithms ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
The Impact

This article presents the results of the optimization of steam generator control systems powered by mixtures of liquid fuels containing biofuels. The numerical model was based on the results of experimental research of steam generator operation in an open system. The numerical model is used to build control algorithms that improve performance, increase efficiency, reduce fuel consumption and increase safety in the full range of operation of the steam generator and the cogeneration system of which it is a component. In this research, the following parameters were monitored: temperature and pressure of the circulating medium, exhaust gas temperature, oxygen content in exhaust gas, percentage control of oil burner power. Two methods of controlling the steam generator were proposed: the classic one, using the PID regulator, and the advanced one, using artificial neural networks. The work shows how the model is adapted to the real system and the impact of the control algorithms on the efficiency of the combustion process. The example is considered for the implementation of advanced control systems in micro-, small- and medium-power cogeneration and trigeneration systems in order to improve their final efficiency and increase the profitability of implementation.

scholarly journals A revised numerical model for parachute inflation based on ALE method

2020 ◽  
Vol 71 (06) ◽  
pp. 515-518
Author(s):  
CHEN CHEN ◽  
QILEI GUO ◽  
PENG SUN
Keyword(s):  
Numerical Model ◽  
Calculated Data ◽  
Element Model ◽  
Euler Method ◽  
Inertia Force ◽  
Peak Time ◽  
Modified Model ◽  
Common Problems ◽  
Parachute Inflation ◽  
Opening Load

The parachute inflation process is a typical time-varying, non-linear and fluid-structure coupling problem, especially inairdrop condition. For its complexity, numerical model of the inflation process is a big challenge, and most of the modelsestablished before still have room for improvement. There were two common problems that the first one was ignoranceof inertia force of canopy and line, and the second was that took stretch speed as the initial airdrop speed in modelling.Thus, a modified finite element model for canopy inflation process based on ALE (Arbitrary Lagrange Euler) method wasestablished that the inertia force of canopy and line was taken into consideration and the initial airdrop speed wasestimated and adjusted. The opening load in finite mass situation during deployment-inflation process of C-9 typeparachute was calculated. The result was compared to experimental data and calculated data of unmodified models. Itwas indicated that the opening load and peak time of modified model was the closest to experiment and the snatch loadwas also calculated and confirmed, so that the correctness and rationality of the model was verified. Then the factorinfluence of inertia force and initial airdrop speed was analysed, which provided a reference for parachute numericalmodelling.

scholarly journals ANALYSIS OF HEAT RELEASE RATE IN ENGINE ROOM FIRES OF 300 GT FERRY RO-RO PASSENGER BY USING WATER MIST SYSTEM AND CO2 SYSTEM

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Wira Setiawan ◽  
Distyan Kotanjungan
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Suppression ◽  
Water Mist ◽  
Engine Room ◽  
Passenger Ships ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
Suppression System

Based on statistical data in recent years, there are still quite a number of ship accidents due to fires, including on passenger ships. The water mist system is a fire suppression system that allows it to be used in the engine room with the advantage that it can keep the heat production rate low during the extinguishing process and can be operated earlier than the CO2 system. The research is conducted by using fire dynamic simulator in the engine room of a 300 GT ferry ro-ro passenger to compare the heat release rate of fire without an extinguishing system, an existing CO2 system, and a water mist system. The result shows that the CO2 fire suppression system reduces the heat release rate more rapidly to the decay phase at 375 seconds while the water mist takes more than 900 seconds. However, the fully developed phase of the water mist suppression system occurs more quickly than CO2 because the sprinklers are activated shortly after a fire occurs. Unlike water mist, the CO2 system is activated at 60 seconds so that the pre-combustion, growth, flashover, and fully developed phases are at the same HRR and time as the natural one.

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