The Experts below are selected from a list of 31035 Experts worldwide ranked by ideXlab platform

Stephen Kerber - One of the best experts on this subject based on the ideXlab platform.

  • Correction to: Analysis of One and Two-Story Single Family Home Fire Dynamics and the Impact of Firefighter Horizontal Ventilation
    Fire Technology, 2019
    Co-Authors: Stephen Kerber
    Abstract:

    The article Analysis of One and Two-Story Single Family Home Fire Dynamics and the Impact of Firefighter Horizontal Ventilation, written by Stephen Kerber, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on August 29, 2012, without open access.

  • Correction to: Analysis of Changing Residential Fire Dynamics and Its Implications on Firefighter Operational Timeframes
    Fire Technology, 2019
    Co-Authors: Stephen Kerber
    Abstract:

    The article Analysis of Changing Residential Fire Dynamics and Its Implications on Firefighter Operational Timeframes, written by Stephen Kerber, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on December 8, 2011, without open access.

  • Analysis of One and Two-Story Single Family Home Fire Dynamics and the Impact of Firefighter Horizontal Ventilation
    Fire Technology, 2013
    Co-Authors: Stephen Kerber
    Abstract:

    This paper describes experimental investigations on Fire service ventilation practices in modern house geometries. Two houses were constructed inside a large Fire facility. The first of two houses constructed was a one-story, 111.5 m^2, 3 bedroom, 1 bathroom house with 8 total rooms. The second house was a two-story 297.3 m^2, 4 bedroom, 2.5 bathroom house with 12 total rooms. The second house featured a modern open floor plan, two-story great room and open foyer. Fifteen experiments were conducted varying the ventilation locations and the number of ventilation openings. Ventilation scenarios included ventilating the front door only, opening the front door and a window near and remote from the seat of the Fire, opening a window only and ventilating a higher opening in the two-story house. One scenario in each house was conducted in triplicate to examine repeatability. The results of these experiments examine potential occupant tenability and provide knowledge for the Fire service for them to examine their horizontal ventilation standard operating procedures and training content. The Fire Dynamics resulting from ventilation practices such as ventilation near or remote from the seat of the Fire and high versus low in relation to the Fire are examined. Several other tactical considerations were developed utilizing the data from these experiments to provide specific examples of changes that can be adopted based on a departments current strategies and tactics. Such tactical considerations and a systems approach to Fire service tactics should be investigated further.

  • Analysis of Changing Residential Fire Dynamics and Its Implications on Firefighter Operational Timeframes
    Fire Technology, 2012
    Co-Authors: Stephen Kerber
    Abstract:

    There has been a steady change in the residential Fire environment over the past several decades. These changes include larger homes, different home geometries, increased synthetic fuel loads, and changing construction materials. Several experiments were conducted to compare the impact of changing fuel loads in residential houses. These experiments show living room Fires have flashover times of less than 5 min when they used to be on the order of 30 min. Other experiments demonstrate the failure time of wall linings, windows and interior doors have decreased over time which also impact Fire growth and Firefighter tactics. Each of these changes alone may not be significant but the all-encompassing effect of these components on residential Fire behavior has changed the incidents that the Fire service is responding to. This analysis examines this change in Fire Dynamics and the impact on Firefighter response times and operational timeframes.

Randall J. Mcdermott - One of the best experts on this subject based on the ideXlab platform.

  • Development and evaluation of two new droplet evaporation schemes for Fire Dynamics simulations
    Fire Safety Journal, 2017
    Co-Authors: Jason E. Floyd, Randall J. Mcdermott
    Abstract:

    Abstract The evaporation of sprinkler droplets is an important phenomenon in Fire simulations both for heat removal from the gas and for heat removal from surfaces. In this paper, we address the problems of potential numerical instability and super-saturation that may occur in explicit time integration of the droplet equations. Two novel numerical approaches are developed and evaluated. The first is based on an analytical solution that relaxes the cell composition and temperature toward the equilibrium values. The second method is an implicit solution to the droplet equations. The two approaches are implemented in the Fire Dynamics Simulator (FDS) and verified and validated using both single droplet and practical sprinkler calculations. Ultimately, the implicit approach is deemed the most cost effective for practical Fire simulations.

  • Quality assessment in the Fire Dynamics Simulator: A bridge to reliable simulations | NIST
    2011
    Co-Authors: Randall J. Mcdermott
    Abstract:

    In this paper, we examine the emerging field of quality assessment for large-eddy simulation of Fire Dynamics. The importance of model convergence is discussed and the differences between validation and quality assessment are highlighted. Briefly, validation compares a model to experimental data, whereas quality assessment fills the void between experiments and practical applications. Two quality metrics are discussed: a measure of turbulence resolution and a normalized wavelet error measure. The metrics are monitored in a simulation of the Sandia 1 m methane pool Fire and target metric values are inferred based on the results of a grid resolution study.

  • A Simple Reaction Time Scale for Under-Resolved Fire Dynamics
    Fire Safety Science, 2011
    Co-Authors: Randall J. Mcdermott, Kevin B. Mcgrattan, Jason E. Floyd
    Abstract:

    A reaction time scale model is developed for use in the eddy dissipation concept (fast chemistry limit) closure of the mean chemical source term in large-eddy simulation of Fires. The novel aspect of the model is to consider a scaling regime for coarse mesh resolution based on buoyant acceleration. The model computes local time scales for diffusion, turbulent advection, and buoyant acceleration and takes the minimum of these as the local mixing time. The new model is implemented in the Fire Dynamics Simulator (FDS) and tested by comparing flame height predictions to the Heskestad correlation.

  • Fire Dynamics Simulator Version 6: Complex Geometry, Embedded Meshes, and Quality Assessment | NIST
    2010
    Co-Authors: Randall J. Mcdermott, Glenn P. Forney, Kevin B. Mcgrattan, William Mell
    Abstract:

    The Fire Dynamics Simulator (FDS) and Smokeview (SMV) are compu- tational and visualization tools specically designed for large-eddy simulations (LES) of low-speed, thermally driven

William Mell - One of the best experts on this subject based on the ideXlab platform.

  • Detailed physical modeling of wildland Fire Dynamics at field scale - An experimentally informed evaluation
    Fire Safety Journal, 2020
    Co-Authors: Eric Mueller, William Mell, Nicholas Skowronski, Kenneth L. Clark, Michael Gallagher, Albert Simeoni, Rory Hadden
    Abstract:

    Abstract Computational Fluid Dynamics (CFD) models are powerful research tools for studying Fire Dynamics. However, their application to wildland Fire scenarios requires evaluation against relevant experimental data. To progress our current understanding of the fidelity of a CFD approach to simulating wildland Fire Dynamics, a dataset from an experimental Fire was used as a test case. First, implications of the level of detail provided to the model, in the form of fuel structure and wind, are evaluated. Second, the predictions of both Fire behavior (e.g. spread rate) and the driving combustion processes (e.g. heat flux) are compared to the experiment. It was found that both increasing the detail in canopy fuel structure and implementing turbulent boundary conditions had a minor impact. It was further found that the model reproduced Fire behavior in the mid-range of experimental observations and that the representation of local combustion processes was qualitatively consistent. This work demonstrates the promising capabilities of the modeling approach used here, while showing that some of its aspects require further investigation and possibly more development.

  • Advancing the Science of Wildland Fire Dynamics Using Process-Based Models
    Fire, 2018
    Co-Authors: Chad M. Hoffman, William Mell, Carolyn Hull Sieg, Rodman R. Linn, Russell A. Parsons, Justin P. Ziegler, J. Kevin Hiers
    Abstract:

    As scientists and managers seek to understand Fire behavior in conditions that extend beyond the limits of our current empirical models and prior experiences, they will need new tools that foster a more mechanistic understanding of the processes driving Fire Dynamics and effects. Here we suggest that process-based models are powerful research tools that are useful for investigating a large number of emerging questions in wildland Fire sciences. These models can play a particularly important role in advancing our understanding, in part, because they allow their users to evaluate the potential mechanisms and interactions driving Fire Dynamics and effects from a unique perspective not often available through experimentation alone. For example, process-based models can be used to conduct experiments that would be impossible, too risky, or costly to do in the physical world. They can also contribute to the discovery process by inspiring new experiments, informing measurement strategies, and assisting in the interpretation of physical observations. Ultimately, a synergistic approach where simulations are continuously compared to experimental data, and where experiments are guided by the simulations will profoundly impact the quality and rate of progress towards solving emerging problems in wildland Fire sciences.

  • Local measurements of wildland Fire Dynamics in a field-scale experiment
    Combustion and Flame, 2018
    Co-Authors: Eric Mueller, Rory Hadden, William Mell, Nicholas Skowronski, Kenneth L. Clark, Michael Gallagher, Jan C. Thomas, Albert Simeoni
    Abstract:

    Abstract Local point measurements of Fire Dynamics in field-scale experiments of wildland Fires are highly useful. This is true both for understanding the mechanisms driving Fire spread that result in the observed macroscopic behaviors, but also in terms of providing comparison points for numerical tools, such as detailed physics-based Fire behavior models. This work describes measurements of temperature, velocity, and radiative heat flux that were made in a field-scale Fire experiment in a pine forest, with the aim of providing both of the above benefits. Regions of both surface Fire and crown Fire were captured and are compared. The crown Fire exhibited tall upright flames, compared to the shorter tilted flames of the surface Fire. Crown Fire resulted in a significant increase in integrated radiative preheating, by a factor of ∼1.75, as well as greater flow sheltering in the downstream region of the Fire front. Further, a corrective factor is introduced for oblique sensor placement relative to the Fire front, in order to improve the value of these and other measurements, particularly for model comparison. The presented methodology, while able to be improved, is shown to successfully characterize local differences in Fire behavior.

  • Fire Dynamics Simulator Version 6: Complex Geometry, Embedded Meshes, and Quality Assessment | NIST
    2010
    Co-Authors: Randall J. Mcdermott, Glenn P. Forney, Kevin B. Mcgrattan, William Mell
    Abstract:

    The Fire Dynamics Simulator (FDS) and Smokeview (SMV) are compu- tational and visualization tools specically designed for large-eddy simulations (LES) of low-speed, thermally driven

Daniel Alvear - One of the best experts on this subject based on the ideXlab platform.

  • Assessing the influence of the input variables employed by Fire Dynamics simulator (FDS) software to model numerically solid-phase pyrolysis of cardboard
    Journal of Thermal Analysis and Calorimetry, 2019
    Co-Authors: Alain Alonso, Mariano Lázaro, Pedro Lázaro, David Lázaro, Daniel Alvear
    Abstract:

    Understanding a material’s Fire behaviour implies to know the thermal decomposition processes. Thermal analysis techniques are widely employed to study thermal decomposition processes, especially to calculate the kinetic and thermal properties. Cardboard boxes are widely employed as rack-storage commodities in industrial buildings. Hence, the characterization of the cardboard is considered a key factor for Fire safety engineering, because it enables the determination of its thermal behaviour at high temperatures. The employment of mathematical or computational models for modelling the thermal decomposition processes is commonly used in Fire safety engineering (FSE). The Fire Dynamics simulator (FDS) software is one of the most commonly used computational fluid Dynamics softwares in FSE to address thermal analysis. To properly set up FDS and obtain accurate results, the numerical values of the thermal and kinetic properties are needed as input data. Owing to the large number of variables to be determined, a preliminary study is bound to be helpful, which can well assess the influence of each variable over the pyrolysis model, discarding or restricting their influence. This study, based on the Monte Carlo method, presents a sensitivity analysis for the variables utilized as input data by the FDS software. The results show the conversion factor α , i.e. the mass involved in each reaction, and the triplet kinetics have a major impact on the reproduction of the thermal decomposition process in Fire computer modelling.

Jen-hao Chi - One of the best experts on this subject based on the ideXlab platform.

  • Using thermal analysis experiment and Fire Dynamics Simulator (FDS) to reconstruct an arson Fire scene
    Journal of Thermal Analysis and Calorimetry, 2012
    Co-Authors: Jen-hao Chi
    Abstract:

    PU foam samples which had caused Fire to spread in an actual arson case were collected for thermal analysis experiments. The experiments were conducted at three different heating rates to obtain thermal reaction parameters including ~3,518.23–5,127.81 J g−1 of heat release at temperatures between 395 and 433 °C. The thermal analysis data were treated as the input data for the Fire Dynamics Simulator program. Results of smoke layers falling in the simulation space were compared and verified with the heights of smoke traces at the actual Fire scene to obtain heating rates which are close to the actual conditions for the reconstruction of the entire Fire scene. In addition to serving as a reference for the investigation and reconstruction of other Fire cases, these research findings can also increase the awareness of the harmful aspects of PU foam for Fire prevention in the future.

  • Reconstruction of an inn Fire scene using the Fire Dynamics Simulator (FDS) program.
    Journal of forensic sciences, 2012
    Co-Authors: Jen-hao Chi
    Abstract:

    An inn Fire occurring in the middle of the night usually causes a great deal more injuries and deaths. This article examines the case study of an inn Fire accident that resulted in the most serious casualties in Taiwan's history. Data based on the official Fire investigation report and NFPA921 regulations are used, and the Fire scenes are reconstructed using the latest Fire Dynamics Simulator (FDS) program from NIST. The personnel evacuation time and time variants for various Fire hazard factors of reconstructive analysis clarify the reason for such a high number of casualties. It reveals that the FDS program has come to play an essential role in Fire investigation. The close comparison between simulation result and the actual Fire scene also provides Fire prevention engineers, a possible utilization of FDS to examine the effects of improved schemes for Fire safety of buildings.

  • Metallographic Analysis and Fire Dynamics Simulation for Electrical Fire Scene Reconstruction
    Journal of Forensic Sciences, 2011
    Co-Authors: Jen-hao Chi
    Abstract:

    This study demonstrated the use of metallographic analysis and NIST's Fire Dynamics Simulator (FDS) program to identify the cause of an actual electrical Fire. A severely carbonized steel plate and a cable with a bead were found inside a damaged switchboard from the debris of a factory Fire. By metallographic analysis, the copper spatter on the steel plate was found to imply a short circuit has occurred and that this was the probable ignition source of the Fire was supported by the presence of a small amount of copper oxide and by the cavities with the tree-like grain microstructures in the bead. The heat estimated to have been released per unit area of the switchboard in question (approximately 236.29 MJ/m(2)) served as key input data for applying the FDS simulation of the blaze. The simulation indicated that thermal insulation polyethylene (PE) played an important role in the rapid Fire spread. Language: en