bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comprehensive Model for Wood Pyrolysis Incorporating Detailed Chemical Reactions and Porous Medium Interactions
Authors: Cuong Dinh Duy , Richard Franck , Batiot Benjamin , Rogaume Thomas 
Published: November 2024

Abstract
A comprehensive model for wood pyrolysis has been developed. This model integrates detailed chemical reactions and interactions between chemistry, heat, and mass transfers within the porous medium. The Ranzi’s reaction scheme [1] is well-known for its detailed and comprehensive modelling of wood components (cellulose, hemicellulose, and lignin). This work extends Ranzi’s scheme to include secondary reactions for tars, which cannot be neglected when wood samples behave as thermally thick materials, as is often the case during fire scenarios involving woody materials. A novel aspect of this model is its detailed consideration of gas-solid interactions within wood pores, incorporating mass and heat transfer mechanisms. The model is based on the PATO code (Porous Analysis Toolbox based on OpenFOAM), which treats the porous medium as a continuum by using a homogenization process to establish conservation equations for averaged quantities defined on a Representative Elementary Volume (REV). This model is applied to simulate cone calorimeter experiments of wood thermal decomposition in a nitrogen-rich environment, providing detailed insights into the complex interplay of chemical and physical processes during pyrolysis. The results highlight the model’s potential as a powerful tool to predict wood thermal decomposition in cases of thermally thick sample behavior, where secondary tars reactions play a key role in describing the entire dynamics of the pyrolysis process at high temperatures.
Effect of flow velocity, atmosphere and sample thickness on the mass loss rate of PMMA in the tube furnace
Authors: De Lannoye K , Belt A , Hasalová L , Arnold L 
Published: November 2024

Abstract
The experiments in this contribution have been conducted in an adapted tube furnace, a new gram scale experiment, based on the ISO 19700, in which an online mass loss measurement has been installed. The benefit of this set-up is that it allows to conduct gram-scale pyrolysis experiments under well-defined boundary conditions. In this set-up, samples with a length up to 50 cm can be investigated under different atmospheres and flow rates. In this contribution, the effect of several experiment parameters on the mass loss rate is studied. For this purpose, black cast PMMA samples were heated at a constant heating rate of 5 K/min. The atmosphere as well as the flow rate through the tube furnace were varied. Additionally, samples with different thicknesses were tested. It was observed that unless the sample auto-ignites, different flow rates do not result in differences in the mass loss rate. Nitrogen versus air atmosphere does make a significant difference on the mass loss rate. Under air atmosphere the PMMA reacts at lower temperature than under nitrogen atmosphere. The thicker the sample, the more the peak mass loss rate shifts to higher temperature and the lower the normalised peak mass loss rate.
Autoignition-based simplified kinetic models of hydrocarbon oxidation for fire simulations
Authors: Moorthamers Y. , Snegirev A. , Maragkos G. , At Thabari J. , Merci B. 
Published: November 2024

Abstract
The possibility of a global reaction model to predict the autoignition delay times of stoichiometric fuel-air mixtures with the accuracy corresponding to that obtained using the most comprehensive chemical mechanisms is demonstrated. To make the global reaction model applicable in a wide temperature range, the effective kinetic parameters are set temperature dependent. These parameters are derived for alkane (from methane to n-heptane and alkene (ethylene and propylene) fuels. Complicated and non-monotonic dependencies of autoignition delay time on temperature, such as those in which an interval with negative temperature dependence exist, are replicated. Compared to the detailed chemical mechanisms, use of the global reaction model offers considerable reduction of computational cost yet retaining capability of predicting critical phenomena of flame extinction and re-ignition in under-ventilated or strained flames.
Experimental and Numerical Study on Fire Suppression via Water Mist in a Mechanically Ventilated Compartment
Authors: Acherar Lahna , Wang Hui-Ying , Coudour Bruno , Pierre Garo Jean 
Published: November 2024

Abstract
The present work provides a detailed experimental and numerical study on suppression phenomena via water mist of a buoyant, turbulent fire over liquid (heptane) surface. It is found that water mist in a hot confined environment allows to achieve maximum droplet evaporation in the smoke layer, and however, it does not conduct to suppression of a fully developed fire due to re-ignition of unburnt fuel. Through the analysis on HRR, gas temperature, heat flux and chemical species, it is concluded that in a hot environment, a consecutive efficient cooling of smoke layer leads to the fire suppression only at lower ACPH (Air Change Per Hour) via lack of oxygen.
A Basic Study on the Temperature Characteristics of the Top of the Rack-type Warehouse Combustibles
Authors: Kim YunSeong , Kang Hyun , Kweon OhSang 
Published: November 2024

Abstract
The temperature characteristics of the fire plume rising above combustibles were examined through experiments simulating fires that occur in combustibles stored in a rack. The fire plume temperature rising above the combustibles was proportional to three times the dimensionless distance r/z, and the average temperature distribution according to the dimensionless distance showed that the edge temperature at 3.6 m was higher than the temperature at 1.2 m and 2.4 m due to the influence of the ceiling.
Burning Rate and Carbon Monoxide Production for an elevated pool fire in a weakly ventilated compartment
Authors: Georges E , Pretrel H , Varrall K , Vauquelin O 
Published: November 2024

Abstract
This work concerns the study of fires in ventilated compartments, and in particular scenarios involving fire located in the upper part of a room near ceilings in under-ventilated conditions. A reduced-scale experimental study with dodecane pool fires was carried out to investigate the combined influence of fire elevation and compartment ventilation flowrate. The fire characteristics of interest are burning rate and CO production. The results show that fire elevation and ventilation flow rate have opposite influence on burning rate. The net balance is a positive effect of elevation, increasing the burning rate even in an oxygen-poor environment. On the contrary, elevation and ventilation flowrate have the same positive influence on CO production and contribute to its increase. This work shows the complexity of a fire in the upper part of a poorly ventilated room and provides new knowledge to improve its prediction for safety assessments.
Zone modeling of timber compartment fires with increasing combustible surfaces: modification to the Semenov’s model
Authors: Calderón I. , Calderón-Vásquez I. , Battisti F. G. , Majdalani A. H. , Jahn W. 
Published: November 2024

Abstract
The traditional compartment fire framework has been the safety standard in fire engineering codes and design standards. Incorporating potentially combustible materials has led to reevaluating the foundations of this science. A simplified compartment fire model is proposed, modifying Semenov’s model to quantify the fuel contribution of an exposed timber element to the compartment fire and determine the impact of this variable on the occurrence of a flashover. By involving a time-dependent component, the proposed model behavior approaches experimental observations. The overall results show that the larger the fuel surface area, the more certain flashover will occur.
Thermal characterization of downward ventilation flows through a smoke layer
Authors: Perrin Loïc , Pretrel Hugues , Varrall Kevin , Vauquelin Olivier 
Published: November 2024

Abstract
Understanding the behaviour of downward flows of fresh air in temperature-stratified compartments is crucial for improving oxygenation of fire in confined compartment. This study investigates the axial temperature profiles of such flows and their sensitivity to injection rates. Experimental tests in a stratified compartment reveal a naturally bounded flow that transitions between a plume and a collapsing fountain, with the ability to transport heat and to affect the thermal stratification. However, different injection rates reveal potential distinct flow configurations. Low rates limit heat transfer potential to upper locations, while high rates lead to colder air reaching the lower part of the compartment. These findings highlight the significance of injection conditions in predicting the fire source environment. Improving such predictions is critical for ensuring accurate prediction of oxygen concentration in the near field of a fire.
Natural Convection on a Vertical Surface: Direct Numerical Simulation versus Empirical Correlations
Authors: Dehghani P. , Chaudhari D. M. , DiDomizio M. J. 
Published: November 2024

Abstract
Convective heat flux to surfaces is an essential component of fire safety analyses. Heat transfer from fires to surfaces by natural convection is typically represented in fire models using empirical correlations; however, these models are often constrained by specific experimental conditions and may not universally apply to all scenarios. A universal correlation that considers all influential variables has yet to be established. The limitations of these models for convective heat transfer, and their suitability for fire modelling, must be identified. This study performs a comprehensive evaluation of prominent natural convection correlations from the literature against a benchmark dataset. The primary objective was to examine the existing correlations quantitatively, and adjust the correlations using a universal and systematic approach. Direct numerical simulation was employed to investigate convective heat transfer on a vertical plate in a still ambient, and simulation results were validated against experimental data. Predictions of the natural convection correlations were then compared to the simulation results, and their effectiveness over differing ranges of Rayleigh numbers and surface temperatures was evaluated. Correction factors were determined to improve the accuracy of the top-performing correlations in each flow regime, thereby enhancing their applicability in fire safety.
Impact of Oxygen Concentrations on the Development of Fires in Ventilation Limited Environments
Authors: Lakhani Ayaan , DiPaola Alexander , Senez Peter , Weckman Elizabeth 
Published: November 2024

Abstract
Large-scale fire tests at the University of Waterloo compare behaviour of a Canadian non-fire retardant faux leather couch and a UK fire-retardant faux leather couch of the same construction under ventilation limited conditions. Results reveal that both fuel loads reach maximum, but different, mass loss rates at minimum oxygen concentration in the environment. Following this, they document the rapid decay in fuel mass loss rate with consequent decrease in temperature through the burn structure. Time-varying volatile organic compounds and carbon monoxide data show preferential increase in concentration as combustion efficiency decreases. The paper adds novel time varying, simultaneously collected fuel mass, temperature and concentration data with aim to provide new insight into the full evolution of compartment fires through transition from early growth to ventilation limited conditions and subsequent fire decay.
Experimental study of fire propagation along a vertical wall in a lab scale device
Authors: Di Giorgio F. , Galizzi C. , Kühni M. 
Published: November 2024

Abstract
A Characterization study was conducted out on a novel experimental apparatus designed for investigating the spread of façade fires. This setup features a wall divided into an effusion zone, where methane injection mimics the pyrolysis process, and a substantial inert zone where the flame propagates. Various flow rates were applied to the effusion module and compared using direct visualizations, CH* and OH* chemiluminescence imaging, as well as temperature, heat flux and velocity measurements. These analyses underscore and validate the well-documented impact of fuel injection rates on flame characteristics and propagation. This standardized configuration establishes a benchmark case, pivotal for comparing with more complex scenarios involving alternative arrangements of effusive and inert zones. Furthermore, the data generated in this study furnish a foundation for assessing the reliability of fire engineering codes.
Sensitivity of wildfire modelling to physical parameters
Authors: Richards Imogen , Restuccia Francesco 
Published: November 2024

Abstract
This paper explores the sensitivity of a fire model to various physical parameters. Models can provide valuable insights into fire behavior, and understanding how sensitive these models are to their inputs is crucial for assessing the impact of data quality. Based on experiments and modelling of piloted ignition of live forest fuels, Fire Dynamics Simulator is used to model a lab-scale fire, with pine needles representing the fuel on a forest floor, under external radiation and forced convection conditions. The sensitivity of the model is analysed using scatter and one-at-a-time analyses. The model results are characterised using the outputs peak heat release rate (pHRR) and time to peak heat release rate. The analysis showed that over the eight studied parameters, the most significant ones affecting time to pHRR were emissivity and fuel moisture content, whilst bulk density and moisture content affected pHRR value most. Overall the parameters which had the greatest effect on the outputs were fuel moisture content and fuel element surface-volume ratio.
Citizen responsive contributions in wildfire crisis Lessons about Shared Responsibility from the 2021 Finsjö fire
Authors: Hovart Lucas , Eriksson Kerstin , Frykmer Tove , McNamee Margaret 
Published: November 2024

Abstract
In 2021, the village Finsjö in Sweden experienced an abnormally large wildfire. During an intervention lasting for 6 days, Fire and Rescue Services [FRS] received spontaneous help from volunteers, leading to valuable contributions but also questions regarding how to address division of responsibilities. Through qualitative interviews with the FRS, this study explores the interaction between formal and informal responsibilities and how FRS representatives perceive spontaneous volunteer contributions. We will show how informal response benefits come from complementing formal duties by answering to specific kinds of needs, and how challenges emerge from questions of dependence and accountability.
Simulation of Complete or Incomplete Biomass Degradation under Parameterized Wildland Fire Spread Conditions
Authors: Mohsen Ahmed Mohamed , Al-Bulqini Hazem M. , Trouvé Arnaud , Forthofer Jason , Finney Mark 
Published: November 2024

Abstract
Our objective in the present study is to provide fundamental insights into the main factors that control the thermal degradation processes occurring inside the biomass vegetation during wildland fire spread. These processes determine the formation of flammable volatiles through pyrolysis reactions and the intensity of the internal heat release through char oxidation reactions; both aspects are central to flaming and smoldering combustion. We adopt here a simplified framework in which the biomass vegetation is viewed as a population of discrete elongated particles that are made of pine wood, are cylindrical-shaped and feature different diameters. The exposure conditions experienced by these particles in an assumed fire are characterized by a given intensity of the external thermal load, a given duration during which this load is applied, and a given external flow velocity that controls the rates of convective heat transfer and oxygen mass transfer. The response of the biomass particles is studied using a one-dimensional computational model, called the particle burning rate (PBR) model. The PBR model adopts a porous medium formulation, and provides a description of drying, (thermal and oxidative) pyrolysis, and char oxidation. We focus in the present study on the conditions required for complete “fuel consumption”, i.e., for complete particle degradation from virgin solid to ash. It is found that in thin biomass particles, complete biomass degradation requires sufficiently high intensities of the external thermal load and sufficiently low external flow velocities; high flow velocities correspond to excessive cooling effects. Similarly, in thick biomass particles, complete biomass degradation requires sufficiently high intensities of the external thermal load, sufficiently long application times of the thermal load, and sufficiently high external flow velocities; low flow velocities correspond to insufficient oxygenation of the (exothermic) oxidative pyrolysis and char oxidation reactions.
Extinction of gas burner with minimum water flow rate discharge from a water mist
Authors: Lapillonne Lucie , Collin Anthony , Mehaddi Rabah , Russo Patrice , Truchot Benjamin 
Published: November 2024

Abstract
Fire extinguishing systems tend to be optimized by impinging a reduced amount of water, with controlled droplet diameter distribution. This paper investigates the minimum water flow rate required for extinguishing a fire experimentally. A gas burner is placed under a water mist nozzle to expose the fire to a controlled water discharge, gradually increasing the volumetric flow rate injected. The water mist consists of a full cone jet, generated thanks to a single nozzle, with a 100 to 300 μm particle diameter. One of the specific characteristics of water mist is the injection of small particle diameters. Thanks to their high exchange surface between droplets and the ambient, the evaporation rate is increased, which contributes to facilitating fire extinction. The main mechanisms involved in the extinction process are the cooling of the reaction zone and the reduction of the oxygen concentration by putting steam directly in this reaction zone. Some research works were published to correlate the required water flow rate to extinguish a fire but based on small-scale tests, typically with HRR lower than 50 kW. This paper aims to check whether or not these relations can be applied to higher heat release rates and higher flow rates in order to determine the critical water flow rate that extinguishes the fire. A set of normalized parameters have been used to comprehend the extinction phenomenon and to analyse the experimental data. The tendency of averaged results shows a predictable extinction rate and consolidates literature data.
Detecting Firefighter’s Thermal Risks in a Commercial Building Structure Using Machine Learning
Authors: Tong Qi , William Stroup David , Cheong Tam Wai , Fang Hongqiang 
Published: November 2024

Abstract
A multi-input and multi-output (MIMO) machine learning model is developed to simultaneously detect firefighter’s thermal risks in a commercial building structure. A total of 2,000 numerical experiments with a wide range of fire and ventilation scenarios are carried out using Fire Dynamics Simulator. Temperature data is obtained from sensors over a simulation duration of 900 s with a 5-s time step. A dataset consisting of 242,000 instances is constructed. The instances are labeled by four thermal operating conditions and are pre-processed for the purpose of training, validating, and testing a machine learning model. Model performance of the MIMO model is provided, and it is benchmarked against typical multi-input and single-output (MISO) machine learning models in terms of accuracy and computation time. Results show that the MIMO model can provide the same accuracy as MISO in detections of thermal operating conditions at multiple locations simultaneously but 10 times faster in computation than MISO. MIMO achieves almost the same recall and precision as MISO except for two locations with binary classes caused by fluctuations in the labels. This research demonstrates the potential of using machine learning methodologies to develop practical firefighting applications which can, in turn, enhance firefighters’ situational awareness and improve their safety measures during firefighting and/or carrying out search-and-rescue in a large commercial building structure.
Foam concentrate rheology and foam system design
Authors: Meyer David J , Herrera Diaz Luis , Dlugogorski Bogdan Z 
Published: November 2024

Abstract
NFPA and EN design standards for systems of firefighting foams devolve the problem of flow calculations for each foam concentrate to the product manufacturers. The data provided by manufacturers do not represent the engineering specifications needed for foam system design. This contribution examines the rheology of foam concentrates, comprising three FfreeF (fluorine-free foams) and one AR-AFFF (alcohol-resistant aqueous film-forming foam). These foam concentrates comprise solutions of polymers (predominantly polysaccharides) combined with surfactants and solvents. We reveal that all products exhibit significant shear thinning and that the formulations display substantial yield stress and slow response to changes in stress. These foam concentrates are sensitive to shearing and require many hours to recover from any deformation during handling. These non-Newtonian properties of the concentrates arise mainly from the presence of polysaccharides in their chemical make-up. We provide guidance for the types of measurement needed to provide engineering specifications for fire system designers and the limits of use for these measurements. The contribution highlights the design implications of the slow-yielding foam concentrates for design of foam-based fire-suppression systems.
On the increase of carbon monoxide production during fire suppression with a water mist spray
Authors: Miyanoiri Yuta , Tanaka Futoshi , Beji Tarek 
Published: November 2024

Abstract
The paper presents an experimental study on fire suppression using a water mist spray. The fire source is a circular propane gas burner with diameters between 0.15 m and 0.25 m, and corresponding to theoretical heat release rates between 3.7 and 40.2 kW. The water mist nozzle with an orifice diameter of 0.69 mm diameter was positioned at 1 m above the fire source and delivered water flow rates between 0.15 and 0.76 L/min. The volume-median diameter of the water droplets ranged between approximately 172 and 242 μm. The whole assembly was under a hood to collect and analyse the combustion products. In this paper, the analysis is focused on carbon monoxide production during water spray activation. The results show that the CO yield can increase by up to 14 times in comparison to the values without a water spray. A preliminary Computational Fluid Dynamics (CFD) simulation using a two-step chemistry mechanism with finite-rate chemistry for CO oxidization has shown qualitatively promising results in capturing the experimental trends.