scholarly journals GoZone: A Numerical Model for Travelling Fires Based on Cellular Automata Concept

2021 ◽  
Vol 11 (22) ◽  
pp. 10679
Author(s):  
Antonio Gamba ◽  
Jean-Marc Franssen
Keyword(s):  
Numerical Model ◽  
Cellular Automata ◽  
Fire Test ◽  
Complex Dynamics ◽  
Zone Model ◽  
Gas Temperature ◽  
Spread Rate ◽  
Fire Dynamics ◽  
Cellular Automata Model ◽  
Practical Solution

Fires in large compartments tend to burn locally and to move across the floor over a period of time; this particular behaviour has been discovered to challenge the assumption of uniform gas temperature in the fire compartment. Recent studies on fires in large compartments have led to the now widely known concept of “travelling fires”. Several models have been proposed to describe the evolution in time of travelling fires. Although these models represented an innovative step in the field of travelling fires, the major drawbacks of these models can be found in the simplification of fire dynamics (constant spread rate, 1D imposed fire path) and limited field of application (rectangular based geometries). The purpose of this paper is to present a numerical model of travelling fire. The model was based on an improved zone model combined with a cellular automata model. The software GoZone, in which the model was implemented, is intended to be a practical solution to analyse fires in large compartments of potentially any shape. GoZone is aimed to describe the complex dynamics of the fire from ignition to a phase of growing localised fire that may eventually travel in the compartment, possibly followed by a flashover. The main sub models comprising GoZone are presented. A comparison is given with the results of under ventilated fire test 2 of the BST/FSR 1993 test series and with respect to the Veselì travelling fire test is shown. GoZone shows a promising capacity to represent fires in a large compartment in both air and fuel controlled fire conditions.

scholarly journals Numerical model of the nanoindentation test based on the digital material representation of the Ti/TiN multilayers

2015 ◽  
Vol 33 (2) ◽  
pp. 348-355 ◽  
Author(s):  
Konrad Perzyński ◽  
Radosław Wiatr ◽  
Łukasz Madej
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Cellular Automata ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Nanoindentation Test ◽  
Cellular Automata Model ◽  
Finite Element Software ◽  
Specific Morphology ◽  
Digital Material

AbstractThe developed numerical model of a local nanoindentation test, based on the digital material representation (DMR) concept, has been presented within the paper. First, an efficient algorithm describing the pulsed laser deposition (PLD) process was proposed to realistically recreate the specific morphology of a nanolayered material in an explicit manner. The nanolayered Ti/TiN composite was selected for the investigation. Details of the developed cellular automata model of the PLD process were presented and discussed. Then, the Ti/TiN DMR was incorporated into the finite element software and numerical model of the nanoindentation test was established. Finally, examples of obtained results presenting capabilities of the proposed approach were highlighted.

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.

Applicability of FLASH-CAT Model to Cable Tray Fire Modeling in Zone Model BRI2002

2020 ◽  
Author(s):  
Koji Shirai ◽  
Koji Tasaka ◽  
Toshiko Udagawa
Keyword(s):  
Mass Loss ◽  
Large Scale ◽  
Fire Test ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Zone Model ◽  
Gas Temperature ◽  
Fire Source ◽  
Gas Burner ◽  
Tray Fire

Abstract To clarify the heat and smoke propagation in multi-compartments under the spread of cable fire, a large-scale multi-compartment fire test (hereinafter the CFS-2 test) was performed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) in France within the framework promoted by the Nuclear Energy Agency (NEA) in Organization for Economic Co-operation and Development (OECD) program PRISME2 (OECD/NEA, 2017). In the CFS-2 test, two rooms of a large-scale facility were adopted and these rooms have an identical volume (120 m3) enclosed with fire walls and were connected by a doorway (0.8 m in width and 2.17 m in height). As a fire source, five-layer cable trays (tray length of 2.4m, tray width of 0.45m and separation distance between trays of 0.3 m) with a fire-retardant PVC cable (77 kg) were used and ignited by a propane gas burner. The power level of the propane gas burner was set to around 80 kW. Moreover, all rooms were mechanically ventilated, and the renewal rate was 15 times per hour (3600 m3/h). During the fire test, the mass loss rate of fuel, gas and soot mass concentration, gas temperature, and etc. were measured. The measured peak values of the HRR, the mass loss rate and gas temperature were about 800 kW, 58 g/s and greater than 600 °C, respectively (Zavaleta, 2017). As a fire model predicting fire characteristics in a compartment, a two-zone model, which divides the fire room into the hot smoke upper layer and lower layer consisting of cool fresh air, is widely used due to the advantages of the brevity of the calculation routine and the reliability of the calculation results. Among them, the BRI2 series, developed in Japan, is now reaching the current BRI2002 software (Wakamatsu, 2004) after several upgrades to improve the calculation precision. The Central Research Institute of Electric Power Industry (CRIEPI) introduced the cable tray fire source model based on the FLASH-CAT (Flame Spread over Horizontal Cable Trays) developed by National Institute of Standards and Technology (NIST) (McGrattan, 2012) into the zone code BRI2002. By comparing the numerical results with the experimental values measured during the CFS-2 test, the methodology for ignition time delay of each tray and horizontal flame propagation speed for each tray were discussed.

A MULTISCALE CELLULAR AUTOMATA MODEL FOR SIMULATING COMPLEX TRANSPORTATION SYSTEMS

2006 ◽  
Vol 17 (10) ◽  
pp. 1437-1459 ◽  
Author(s):  
PAWEŁ TOPA ◽  
WITOLD DZWINEL ◽  
DAVID A. YUEN
Keyword(s):  
Numerical Model ◽  
Cellular Automata ◽  
General Framework ◽  
Transportation Network ◽  
Transportation Systems ◽  
River Systems ◽  
Temporal Scales ◽  
Cellular Automata Model ◽  
Reverse Situation ◽  
Spatio Temporal

We present a new two-level numerical model describing the evolution of transportation network. Two separate but mutually interacting sub-systems are investigated: a starving environment and the network. We assume that the slow modes of the environment growth can be modeled with classical cellular automata (CA) approach. The fast modes representing the transportation network, we approximate by the graph of cellular automata (GCA). This allows the simulation of transportation systems over larger spatio-temporal scales and scrutinizing global interactions between the network and the environment. We show that the model can mimic the realistic evolution of complex river systems. We also demonstrate how the model can simulate a reverse situation. We conclude that the paradigm of this model can be extended further to a general framework, approximating many realistic multiscale transportation systems in diverse fields such as geology, biology and medicine.

Using Cellular Automata to Learn About the Immune System

1998 ◽  
Vol 09 (06) ◽  
pp. 793-799 ◽  
Author(s):  
Rita Maria Zorzenon Dos Santos
Keyword(s):  
Immune System ◽  
Cellular Automata ◽  
Time Evolution ◽  
Collective Behavior ◽  
Complex Dynamics ◽  
Biological Systems ◽  
Immune Repertoire ◽  
Probabilistic Cellular Automata ◽  
Cellular Automata Model ◽  
Simple Systems

Cellular automata are very simple systems that can exhibit complex dynamics on its time evolution. Over the last decade there have been many applications of cellular automata to modeling of biological systems. Those applications have been stimulated by the study of complex systems which has brought many insights into the cooperative and global behavior of the biological systems. Along with this discussion we present two different applications of deterministic and also of probabilistic cellular automata that are used to model the dynamics involved in cooperative and collective behavior of the immune system. In the first example, we use a deterministic cellular automata to model the time evolution of the immune repertoire, as a network, according to the Jerne's theory. Using this model we could reproduce some recent experimental results about immunization and aging of the immune system. In the second example, we use a probabilistic cellular automata model to study the evolution of HIV infection and the onset of AIDS. The results are in excellent agreement with experimental data obtained from infected patients. Besides the examples above, other interesting applications, such as models for cancer and recurrent epidemics, are being considered in the present framework.

A Cellular Automata Model for Nitriding of Nanocrystalline Iron

2015 ◽  
Author(s):  
Jingyi Zhao ◽  
G.-X. Wang ◽  
Yalin Dong ◽  
Chang Ye
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Cellular Automata ◽  
Grain Boundaries ◽  
Nitriding Process ◽  
Nitrogen Diffusion ◽  
Cellular Automata Model ◽  
Grain Sizes ◽  
Nanocrystalline Iron ◽  
Ca Model

In this study, a numerical model was developed to investigate the effects of grain refinement on the efficiency of nitrogen diffusion during the nitriding process. A cellular automata (CA) model without considering the effects of grain boundaries was built to simulate the nitriding process. The results from the numerical model were compared and validated by experimental data in the literature. Then, nanoscale grain boundaries were integrated into this CA model. The nitriding efficiency in materials with different grain sizes was investigated. The results demonstrate that nanocrystallization can significantly increase the nitrogen diffusion efficiency and thus make low temperature (300°C) nitriding possible.

A GIS-Based Irregular Cellular Automata Model of Land-Use Change

2007 ◽  
Vol 34 (4) ◽  
pp. 708-724 ◽  
Author(s):  
Daniel Stevens ◽  
Suzana Dragićević
Keyword(s):  
Land Use ◽  
Cellular Automata ◽  
Land Use Change ◽  
Spatial Data ◽  
Cellular Automata Model ◽  
Population Growth Rates ◽  
Asynchronous Development ◽  
Canadian City ◽  
Ca Model ◽  
Developing Area

This study proposes an alternative cellular automata (CA) model, which relaxes the traditional CA regular square grid and synchronous growth, and is designed for representations of land-use change in rural-urban fringe settings. The model uses high-resolution spatial data in the form of irregularly sized and shaped land parcels, and incorporates synchronous and asynchronous development in order to model more realistically land-use change at the land parcel scale. The model allows urban planners and other stakeholders to evaluate how different subdivision designs will influence development under varying population growth rates and buyer preferences. A model prototype has been developed in a common desktop GIS and applied to a rapidly developing area of a midsized Canadian city.

scholarly journals Tensor approach to software implementation of cellular automata model of diffusion

2020 ◽  
Vol 1680 ◽  
pp. 012035
Author(s):  
A K Matolygin ◽  
N A Shalyapina ◽  
M L Gromov ◽  
S N Torgaev
Keyword(s):  
Cellular Automata ◽  
Software Implementation ◽  
Cellular Automata Model
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