scholarly journals Numerical Fire Spread Simulation Based on Material Pyrolysis—An Application to the CHRISTIFIRE Phase 1 Horizontal Cable Tray Tests

Fire ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 33
Author(s):  
Tristan Hehnen ◽  
Lukas Arnold ◽  
Saverio La Mendola
Keyword(s):  
Experimental Data ◽  
Cone Calorimeter ◽  
Material Parameter ◽  
General Procedure ◽  
Phase 1 ◽  
Inverse Modelling ◽  
Fire Dynamics ◽  
Total Energy Release ◽  
Fire Propagation ◽  
Cone Calorimeter Test

A general procedure is described to generate material parameter sets to simulate fire propagation in horizontal cable tray installations. Cone Calorimeter test data are processed in an inverse modelling approach. Here, parameter sets are generated procedurally and serve as input for simulations conducted with the Fire Dynamics Simulator (FDS). The simulation responses are compared with the experimental data and ranked based on their fitness. The best fitness was found for a test condition of 50 kW/m2. Low flux conditions 25 kW/m2 and less exhibited difficulties to be accurately simulated. As a validation step, the best parameter sets are then utilised to simulate fire propagation within a horizontal cable tray installation and are compared with experimental data. It is important to note, the inverse modelling process is focused on the Cone Calorimeter and not aware of the actual validation step. Despite this handicap, the general features in the fire development can be reproduced, however not exact. The fire in the tray simulation extinguishes earlier and the total energy release is slightly higher when compared to the experiment. The responses of the material parameter sets are briefly compared with a selection of state of the art procedures.

scholarly journals Numerical Fire Spread Simulation Based on Material Pyrolysis - An Application to the CHRISTIFIRE Phase 1 Horizontal Cable Tray Tests

2020 ◽  
Author(s):  
Tristan Hehnen ◽  
Lukas Arnold ◽  
Saverio La Mendola
Keyword(s):  
Experimental Data ◽  
Cone Calorimeter ◽  
Material Parameter ◽  
General Procedure ◽  
Phase 1 ◽  
Inverse Modelling ◽  
Fire Dynamics ◽  
Total Energy Release ◽  
Fire Propagation ◽  
Cone Calorimeter Test

A general procedure is described, to generate material parameter sets to simulate fire propagation in horizontal cable tray installations. Cone Calorimeter test data is processed in an inverse modelling approach. Here, parameter sets are generated procedurally and serve as input for simulations conducted with the Fire Dynamics Simulator (FDS). The simulation responses are compared with the experimental data and ranked based on their fitness. The best fitness was found for a test condition of \SI{50}{\kilo\watt\per\meter^2}. Low flux conditions \SI{25}{\kilo\watt\per\meter^2} and less exhibited difficulties to be simulated accurately. As a validation step, the best parameter sets are then utilised to simulate fire propagation within a horizontal cable tray installation and are compared with experimental data. It is important to note, the inverse modelling process is focused on the Cone Calorimeter and not aware of the actual validation step. Despite this handicap, the general features in the fire development can be reproduced, however not exact. The fire in the tray simulation extinguishes earlier and the total energy release is slightly higher as compared to the experiment. The responses of the material parameter sets are briefly compared with a selection of state of the art procedures.

Soot production modelling for operational computational fluid dynamics fire simulations

2020 ◽  
Vol 38 (3) ◽  
pp. 284-308
Author(s):  
Oscar Mariño ◽  
Felipe Muñoz ◽  
Wolfram Jahn
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Large Scale ◽  
Radiation Heat Transfer ◽  
Fire Dynamics ◽  
Fire Propagation ◽  
Simulation Tools ◽  
Fire Engineering ◽  
Fire Modelling

With the aim of minimising the losses produced by fire accidents, fire engineering applies physics and engineering principles to preserve the integrity of people, environment and infrastructure. Fire modelling is complex due to the interaction between chemistry, heat transfer and fluid dynamics. Commercially available simulation tools necessarily simplify this complexity, excluding less fundamental processes, such as soot production. By not including this compound in the simulations, the interactions of radiation heat transfer, fire propagation and toxicity must be approximated based on input parameters that are often not well defined. In this work, two semi-empirical soot models are incorporated in the fire dynamics simulator. The models are compared against experimental data. For the operational viability in large-scale scenarios, a correction factor for the local variables is proposed as a function of the cell size, achieving good agreement with experimental data in terms of the amount of soot generated.

scholarly journals Material parameter identification using finite elements with time-adaptive higher-order time integration and experimental full-field strain information

2021 ◽  
Author(s):  
Stefan Hartmann ◽  
Rose Rogin Gilbert
Keyword(s):  
Experimental Data ◽  
Finite Elements ◽  
Parameter Identification ◽  
Material Parameter ◽  
Measurement Data ◽  
Least Square ◽  
Image Correlation ◽  
Field Strain ◽  
Material Parameter Identification ◽  
Full Field

AbstractIn this article, we follow a thorough matrix presentation of material parameter identification using a least-square approach, where the model is given by non-linear finite elements, and the experimental data is provided by both force data as well as full-field strain measurement data based on digital image correlation. First, the rigorous concept of semi-discretization for the direct problem is chosen, where—in the first step—the spatial discretization yields a large system of differential-algebraic equation (DAE-system). This is solved using a time-adaptive, high-order, singly diagonally-implicit Runge–Kutta method. Second, to study the fully analytical versus fully numerical determination of the sensitivities, required in a gradient-based optimization scheme, the force determination using the Lagrange-multiplier method and the strain computation must be provided explicitly. The consideration of the strains is necessary to circumvent the influence of rigid body motions occurring in the experimental data. This is done by applying an external strain determination tool which is based on the nodal displacements of the finite element program. Third, we apply the concept of local identifiability on the entire parameter identification procedure and show its influence on the choice of the parameters of the rate-type constitutive model. As a test example, a finite strain viscoelasticity model and biaxial tensile tests applied to a rubber-like material are chosen.

scholarly journals Numerical Investigations on the Propagation of Fire in a Railway Carriage

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4999
Author(s):  
Matthew Craig ◽  
Taimoor Asim
Keyword(s):  
Fire Spread ◽  
Ignition Energy ◽  
Fire Dynamics ◽  
Fire Propagation ◽  
Average Temperature ◽  
Smoke Density ◽  
Smoke Layer ◽  
Most Significant Change ◽  
Computational Fluid Dynamics Cfd ◽  
Safety Guidelines

In this study, advanced Computational Fluid Dynamics (CFD)-based numerical simulations have been performed in order to analyse fire propagation in a standard railway compartment. A Fire Dynamics Simulator (FDS) has been employed to mimic real world scenarios associated with fire propagation within railway carriages in order to develop safety guidelines for railway passengers. Comprehensive parametric investigations on the effects of ignition location, intensity and cabin upholstery have been carried out. It has been observed that a fire occurring near the exits of the carriage results in a lower smoke layer height, due to the local carriage geometry, than an identical fire igniting at the center of the carriage. This in turn causes the smoke density along the aisleway to vary by around 30%. Reducing the ignition energy by half has been found to restrict combustion, thus reducing smoke density and carbon exhaust gases, reducing the average temperature from 170 °C to 110 °C. Changing the material lining of the seating has been found to cause the most significant change in output parameters, despite its relative insignificance in bulk mass. A polyester sample produces a peak carbon monoxide concentration of 7500 ppm, which is 27× greater compared with nylon. This difference has been found to be due to the fire spread and propagation between fuels, signifying the polyester’s unsuitability for use in railway carriages.

scholarly journals A Numerical Analysis of the Fire Characteristics after Sprinkler Activation in the Compartment Fire

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3099 ◽  
Author(s):  
Ho Trong Khoat ◽  
Ji Tea Kim ◽  
Tran Dang Quoc ◽  
Ji Hyun Kwark ◽  
Hong Sun Ryou
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Fire Suppression ◽  
Compartment Fire ◽  
Fire Dynamics ◽  
Fire Dynamics Simulator ◽  
Safety Design ◽  
Smoke Layer ◽  
Fire Characteristics ◽  
Sprinkler Spray

Understanding fire characteristics under sprinkler spray is valuable for performance-based safety design. However, fire characteristics during fire suppression by sprinkler spray has seldom been studied in detail. In order to present a fire suppression model by sprinkler spray and determine the fire characteristics after sprinkler activation in a compartment, a numerical analysis was conducted using a fire dynamics simulator (FDS). A simple fire suppression model by sprinkler spray was calibrated by comparing ceiling temperatures from experimental data. An extinguishing coefficient of 3.0 was shown to be suitable for the fire suppression model. The effect of sprinkler spray on the smoke layer during fire suppression was explained, revealing a smoke logging phenomenon. In addition, the smoke, which spread under the influence of the sprinkler spray, was also investigated. The temperature, velocity, and mass flow rate of the smoke layer through the doorway was significantly reduced during fire suppression compared to a free burn case.

A Comparison of the Behaviour of Spruce Wood and Polyolefins during the Test on the Cone Calorimeter

2013 ◽  
Vol 726-731 ◽  
pp. 4280-4287 ◽  
Author(s):  
Jozef Martinka ◽  
Emília Hroncová ◽  
Tomáš Chrebet ◽  
Karol Balog
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Lower Sensitivity ◽  
Average Heat ◽  
Fire Propagation ◽  
Spruce Wood

This article deals with comparison of the behaviour of spruce wood and polyolefins (polyethylene PE and polypropylene PP) during the test on the cone calorimeter. Samples were tested on the cone calorimeter at heat flux of 20 and 40 kW/m2. An evaluation of the behaviour of examined materials was based on the determination of the maximum and the average heat release rate, yield of carbon monoxide (CO), and relative comparison of tendency to fire propagation in a flashover phase. The tendency of materials to fire propagation in the flashover phase was evaluated based on the Pearson ́s correlation, the Spearman ́s correlation and the Kendall ́s correlation coefficient of HRR-CO and CO2-CO. Spruce wood showed better properties in comparison with PE and PP in all evaluated parameters (the maximum and the average heat release rate, the yield of CO, and also the resistance to fire propagation in the flashover phase. Additionally, spruce wood showed significantly lower sensitivity of dependence of the maximum and also the average heat release rate on external heat flux.

Investigation of Flammable Behavior of Nylon 6 Fabrics with and without Spandex Using Cone Calorimeter Test and Vertical Burning Test

2014 ◽  
Vol 852 ◽  
pp. 644-647
Author(s):  
Sheng Li Luo ◽  
Hai Liang Zhang ◽  
Zhi Cheng Zhan ◽  
Bing He Mao ◽  
Zhi Jie Jiang ◽  
...  
Keyword(s):  
Heat Release ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Nylon 6 ◽  
Test Results ◽  
Total Heat Release ◽  
Combustion Behavior ◽  
Textile Fabrics ◽  
Cone Calorimeter Test ◽  
Nylon Fiber

To study the influence of spandex on combustion behavior of textile fabrics, two kinds of nylon 6 fabrics were tested using cone calorimeter test and vertical burning test. Some key combustion parameters such as heat release rate (HRR), total heat release (THR) and rate of smoke release (RSR) were obtained from cone calorimeter test and afterflame time and damaged length from vertical burning test. Results indicated that the nylon 6 fabric containing spandex showed 21% higher HRR value. But THRs of the nylon 6 fabric containing spandex and the pure nylon 6 fabric were close. RSR curves indicated that RSR value of the nylon 6 fabric containing spandex was 73% higher than that of the pure nylon 6 fabric. The afterflame time and damaged length of the nylon 6 fabric containing spandex were much longer than that of the pure nylon 6 fabric. Spandex does accelerate the combustion behavior on Nylon fiber.

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