145 results on '"Torero, J."'
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2. Proceedings of the first workshop organized by the IAFSS Working Group on Measurement and Computation of Fire Phenomena (MaCFP)
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Brown, A, Bruns, M, Gollner, M, Hewson, J, Maragkos, G, Marshall, A, McDermott, R, Merci, B, Rogaume, T, Stoliarov, S, Torero, J, Trouvé, A, Wang, Y, and Weckman, E
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Civil Engineering ,Engineering ,Bioengineering ,Networking and Information Technology R&D (NITRD) ,Buoyant plumes ,Pool fires ,Wall fires ,Flame extinction ,Fire modeling ,Pyrolysis modeling ,Large eddy simulation ,Large Eddy Simulation ,Pyrolysis ,modeling ,Chemical Engineering ,Maritime Engineering ,Civil engineering - Abstract
This paper provides a report of the discussions held at the first workshop on Measurement and Computation of Fire Phenomena (MaCFP) on June 10-11 2017. The first MaCFP work-shop was both a technical meeting for the gas phase subgroup and a planning meeting for the condensed phase subgroup. The gas phase subgroup reported on a first suite of experimental- computational comparisons corresponding to an initial list of target experiments. The initial list of target experiments identifies a series of benchmark configurations with databases deemed suitable for validation of fire models based on a Computational Fluid Dynamics approach. The simulations presented at the first MaCFP workshop feature fine grid resolution at the millimeter- or centimeter- scale: these simulations allow an evaluation of the performance of fire models under high-resolution conditions in which the impact of numerical errors is reduced and many of the discrepancies between experimental data and computational results may be attributed to modeling errors. The experimental-computational comparisons are archived on the MaCFP repository [1]. Furthermore, the condensed phase subgroup presented a review of the main issues associated with measurements and modeling of pyrolysis phenomena. Overall, the first workshop provided an illustration of the potential of MaCFP in providing a response to the general need for greater levels of integration and coordination in fire research, and specifically to the particular needs of model validation.
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- 2018
3. Proceedings of the first workshop organized by the IAFSS Working Group on Measurement and Computation of Fire Phenomena (MaCFP)
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Brown, A., Bruns, M., Gollner, M., Hewson, J., Maragkos, G., Marshall, A., McDermott, R., Merci, B., Rogaume, T., Stoliarov, S., Torero, J., Trouvé, A., Wang, Y., and Weckman, E.
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- 2018
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4. Notre-Dame de Paris as a validation case to improve fire safety modelling in historic buildings
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Guibaud, A., primary, Mindeguia, J.-C., additional, Albuerne, A., additional, Parent, T., additional, and Torero, J., additional
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- 2023
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5. Forced forward smoldering experiments in microgravity
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Bar-Ilan, Amnon, Rein, Guillermo, Fernandez-Pello, A Carlos, Torero, J L, and Urban, D L
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smoldering combustion ,microgravity ,forward forced flow ,buoyancy effects - Abstract
Results from two forward forced-flow smolder tests on polyurethane foam using air as oxidizer conducted aboard the NASA Space Shuttle (STS-105 and STS-108 missions) are presented in this work. The two tests provide the only presently available forward smolder data in microgravity. A complimentary series of ground-based tests were also conducted to determine, by comparison with the microgravity data, the effect of gravity on the forward smolder propagation. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder for the purpose of control and prevention, both in normal- and microgravity. The data consists of temperature histories from thermocouples placed at various axial locations along the fuel sample centerline, and of permeability histories obtained from ultrasonic transducer pairs also located at various axial positions in the fuel sample. A comparison of the tests conducted in normal- and microgravity indicates that smolder propagation velocities are higher in microgravity than in normal gravity, and that there is a greater tendency for a transition to flame in microgravity than in normal gravity. This is due primarily to the reduced heat losses in the microgravity environment, leading to increased char oxidation. This observation is confirmed through a simplified one-dimensional model of the forward smolder propagation. This finding has important implications from the point of view of fire safety in a space-based environment, since smolder can often occur in the forward mode and potentially lead to a smolder-initiated fire. (C) 2004 Elsevier Inc. All rights reserved.
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- 2004
6. Potential Bio-oil Production from Smouldering Combustion of Faeces
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Yermán, L., Cormier, D., Fabris, I., Carrascal, J., Torero, J. L., Gerhard, J. I., and Cheng, Y.-L.
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- 2017
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7. Radiation emission from a heating coil or a halogen lamp on a semitransparent sample
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Boulet, P., Parent, G., Acem, Z., Collin, A., Försth, M., Bal, N., Rein, G., and Torero, J.
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- 2014
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8. Flat plate diffusion flames: Numerical simulation and experimental validation for different gravity levels
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Torero, J. L., Wang, H-Y, Joulain, P., Most, J. M., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Ratke, Lorenz, editor, Walter, Hannes, editor, and Feuerbacher, Berndt, editor
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- 1996
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9. Flammability assessment of tannin-based cellular materials
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Celzard, A., Fierro, V., Amaral-Labat, G., Pizzi, A., and Torero, J.
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- 2011
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10. Structural behaviour during a vertically travelling fire
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Röben, C., Gillie, M., and Torero, J.
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- 2010
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11. Performance Assessment of Pressurized Stairs in High Rise Buildings
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Bellido, C., Quiroz, A., Panizo, A., and Torero, J. L.
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- 2009
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12. Laser-induced incandescence calibration in a three-dimensional laminar diffusion flame
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Fuentes, A., Legros, G., El-Rabii, H., Vantelon, J.-P., Joulain, P., and Torero, J. L.
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- 2007
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13. Evaluation of the extinction factor in a laminar flame established over a PMMA plate in microgravity
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Fuentes, A., Legros, G., Joulain, P., Vantelon, J. P., and Torero, J. L.
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- 2005
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14. Theoretical prediction of piloted ignition of polymeric fuels in microgravity at low velocity flows
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Zhou, Y. Y., Walther, D. C., Fernandez-Pello, A. C., Torero, J. L., and Ross, H. D.
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- 2003
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15. Understanding materials flammability
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LAUTENBERGER, C, primary, TORERO, J, additional, and FERNANDEZ-PELLO, C, additional
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- 2006
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16. Modelling of the collapse of large multi-storey steel frame structures in fire
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USMANI, A, primary, FLINT, G, additional, JOWSEY, A, additional, LAMONT, S, additional, LANE, B, additional, and TORERO, J, additional
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- 2005
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17. Effect of Smoke Source and Horn Configuration on Enhanced Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors*
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Worrell, C. L., Lynch, J. A., Jomaas, G., Roby, R. J., Streit, L., and Torero, J. L.
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- 2003
18. Forced Forward Smoldering Experiments Aboard The Space Shuttle
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Fernandez-Pello, A. C, Bar-Ilan, A, Rein, G, Urban, D. L, and Torero, J. L
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Inorganic, Organic And Physical Chemistry - Abstract
Smoldering is a basic combustion problem that presents a fire risk because it is initiated at low temperatures and because the reaction can propagate slowly in the material interior and go undetected for long periods of time. It yields a higher conversion of fuel to toxic compounds than does flaming, and may undergo a transition to flaming. To date there have been a few minor incidents of overheated and charred cables and electrical components reported on Space Shuttle flights. With the establishment of the International Space Station, and the planning of a potential manned mission to Mars, there has been an increased interest in the study of smoldering in microgravity. The Microgravity Smoldering Combustion (MSC) experiment is part of a study of the smolder characteristics of porous combustible materials in a spacecraft environment. The aim of the experiment is to provide a better fundamental understanding of the controlling mechanisms of smoldering combustion under normal- and microgravity conditions. This in turn will aid in the prevention and control of smolder originated fires, both on earth and in spacecrafts. The microgravity smoldering experiments have to be conducted in a space-based facility because smoldering is a very slow process and consequently its study in a microgravity environment requires extended periods of time. The microgravity experiments reported here were conducted aboard the Space Shuttle. The most recent tests were conducted during the STS-105 and STS-108 missions. The results of the forward smolder experiments from these flights are reported here. In forward smolder, the reaction front propagates in the same direction as the oxidizer flow. The heat released by the heterogeneous oxidation reaction is transferred ahead of the reaction heating the unreacted fuel. The resulting increase of the virgin fuel temperature leads to the onset of the smolder reaction, and propagates through the fuel. The MSC data are compared with normal gravity data to determine the effect of gravity on smolder.
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- 2003
19. Piloted Ignition of Polypropylene/Glass Composites in a Forced Air Flow
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Fernandez-Pello, A. C, Rich, D, Lautenberger, C, Stefanovich, A, Metha, S, Torero, J, Yuan, Z, and Ross, H
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Composite Materials - Abstract
The Forced Ignition and Spread Test (FIST) is being used to study the flammability characteristics of combustible materials in forced convective flows. The FIST methodology is based on the ASTM E-1321, Lateral Ignition and Flame Spread Test (LIFT) which is used to determine the ignition and flame spread characteristics of materials, and to produce 'Flammability Diagrams' of materials. The LIFT apparatus, however, relies on natural convection to bring air to the combustion zone and the fuel vapor to the pilot flame, and thus cannot describe conditions where the oxidizer flow velocity may change. The FIST on the other hand, by relying on a forced flow as the dominant transport mechanism, can be used to examine variable oxidizer flow characteristics, such as velocity, oxygen concentration, and turbulence intensity, and consequently has a wider applicability. Particularly important is its ability to determine the flammability characteristics of materials used in spacecraft since in the absence of gravity the only flow present is that forced by the HVAC of the space facility. In this paper, we report work on the use of the FIST approach on the piloted ignition of a blended polypropylene fiberglass (PP/GL) composite material exposed to an external radiant flux in a forced convective flow of air. The effect of glass concentration under varying external radiant fluxes is examined and compared qualitatively with theoretical predictions of the ignition process. The results are used to infer the effect of glass content on the fire safety characteristics of composites.
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- 2003
20. Enhanced Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors
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Worrell, C. L., Roby, R. J., Streit, L., and Torero, J. L.
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- 2001
21. Theoretical Prediction of Microgravity Ignition Delay of Polymeric Fuels in Low Velocity Flows
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Fernandez-Pello, A. C, Torero, J. L, Zhou, Y. Y, Walther, D, and Ross, H. D
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Inorganic, Organic And Physical Chemistry - Abstract
A new flammability apparatus and protocol, FIST (Forced Flow Ignition and Flame Spread Test), is under development. Based on the LIFT (Lateral Ignition and Flame Spread Test) protocol, FIST better reflects the environments expected in spacebased facilities. The final objective of the FIST research is to provide NASA with a test methodology that complements the existing protocol and provides a more comprehensive assessment of material flammability of practical materials for space applications. Theoretical modeling, an extensive normal gravity data bank and a few validation space experiments will support the testing methodology. The objective of the work presented here is to predict the ignition delay and critical heat flux for ignition of solid fuels in microgravity at airflow velocities below those induced in normal gravity. This is achieved through the application of a numerical model previously developed of piloted ignition of solid polymeric materials exposed to an external radiant heat flux. The model predictions will provide quantitative results about ignition of practical materials in the limiting conditions expected in space facilities. Experimental data of surface temperature histories and ignition delay obtained in the KC-135 aircraft are used to determine the critical pyrolysate mass flux for ignition and this value is subsequently used to predict the ignition delay and the critical heat flux for ignition of the material. Surface temperature and piloted ignition delay calculations for Polymethylmethacrylate (PMMA) and a Polypropylene/Fiberglass (PP/GL) composite were conducted under both reduced and normal gravity conditions. It was found that ignition delay times are significantly shorter at velocities below those induced by natural convection.
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- 2001
22. Characterization of a Laminate Flat Plate Diffusion Flame in Microgravity using PIV, Visible and CH Emissions
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Joulain, P, Cordeiro, P, and Torero, J. L
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Inorganic, Organic And Physical Chemistry - Abstract
Motivated by fire safety concerns and the advent of long-term micro-gravity facilities, a cooperative program has been developed to study the mechanisms and material properties that control flow assisted (co-current) flame spread. This program has used as a common fire scenario a reacting steady-state boundary layer. Preliminary studies explored the aerodynamics of a reacting boundary layer by simulating a condensed fuel by means of a gas burner. Stability curves for ethane air flames were obtained and different burning regimes were identified. An important feature of this study was the independent identification of the different mechanisms leading to the instability of the flow. It was observed that fuel injection velocity and thermal expansion independently contributed to the separation of the flow at the leading edge of the burner. The occurrence of separation resulted in complex three-dimensional flow patterns that have a dominant effect on critical fire safety parameters such as the stand-off distance and flame length. This work was extended to a solid fuel (PMMA) leading to a Sounding Rocket experiment (Mini-Texus-6). The solid phase showed similar flow patterns, mostly present at low flow velocities (<100 mm/s) but the results clearly demonstrated that the thermal balance at the pyrolyzing fuel surface is the dominant mechanism that controls both stand-off distance and flame length. This thermal balance could be described in a global manner by means of a total mass transfer or "B" number. This "B" number incorporates surface re-radiation, radiative feedback and in-depth heat conduction as first prescribed by Emmons. The mass transfer number becomes the single parameter that determines the evolution of these fire safety variables (flame length, stand-off distance) and therefore can be used as a ranking criterion to assess the flammability of materials. The particular configuration is representative of the NASA upward flame spread test (Test 1) therefore this approach can be used in the interpretation of the results obtained from this test. Nevertheless, complete validation of this approach has not been fully achieved due, mainly because all the measurements necessary to compare with the theoretical predictions have not been obtained. Following these studies two different directions have been taken. The first attempts to elucidate the details of the gas phase combustion reaction and the associated flow field by means of quantitative and qualitative measurements. The second approach, a more practical one, is to apply this methodology to the assessment of material flammability. The former is currently being conducted with a gas burner because it allows for easier control and longer experimentation time. The results obtained so far will be presented in more detail. The latter is a new program therefore only a brief summary of the objectives will be presented.
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- 2001
23. Flow Effects on the Flammability Diagrams of Solid Fuels: Microgravity Influence on Ignition Delay
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Cordova, J. L, Walther, D. C, Fernandez-Pello, A. C, Steinhaus, T, Torero, J. L, Quintere, J. G, and Ross, H. D
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Materials Processing - Abstract
The possibility of an accidental fire in space-based facilities is a primary concern of space exploration programs. Spacecraft environments generally present low velocity air currents produced by ventilation and heating systems (of the order of 0.1 m/s), and fluctuating oxygen concentrations around that of air due to CO2 removal systems. Recent experiments of flame spread in microgravity show the spread rate to be faster and the limiting oxygen concentration lower than in normal-gravity. To date, there is not a material flammability-testing protocol that specifically addresses issues related to microgravity conditions. The present project (FIST) aims to establish a testing methodology that is suitable for the specific conditions of reduced gravity. The concepts underlying the operation of the LIFT apparatus, ASTM-E 1321-93, have been used to develop the Forced-flow Ignition and flame-Spread Test (FIST). As in the LIFT, the FIST is used to obtain the flammability diagrams of the material, i.e., graphs of ignition delay time and flame spread rate as a function of the externally applied radiant flux, but under forced flow rather than natural convection conditions, and for different oxygen concentrations. Although the flammability diagrams are similar, the flammability properties obtained with the FIST are found to depend on the flow characteristics. A research program is currently underway with the purpose of implementing the FIST as a protocol to characterize the flammability performance of solid materials to be used in microgravity facilities. To this point, tests have been performed with the FIST apparatus in both normal-gravity and microgravity conditions to determine the effects of oxidizer flow characteristics on the flammability diagrams of polymethylmethacrylate (PMMA) fuel samples. The experiments are conducted at reduced gravity in a KC- 135 aircraft following a parabolic flight trajectory that provides up to 25 seconds of low gravity. The objective of the experiments is to obtain data of ignition delay and flame spread rate at low flow velocities (0.1 to 0.2 m/s), which cannot be obtained under normal gravity because of the natural convection induced flows (approx. 0.5 m/s). Due to the limited reduced gravity time, the data can only be obtained for high radiant fluxes, and are consequently limited in scope. These tests do, however, provide insight into the flammability diagram characteristics at low velocity and reduced gravity, and also into the implications of the flow-dependence of the flammability properties under environments similar to those encountered in space facilities.
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- 1999
24. A Method for Assessing Material Flammability for Micro-Gravity Environments
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Steinhaus, T, Olenick, S. M, Sifuentes, A, Long, R. T, and Torero, J. L
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Inorganic, Organic And Physical Chemistry - Abstract
On a spacecraft, one of the greatest fears during a mission is the outbreak of a fire. Since spacecraft are enclosed spaces and depend highly on technical electronics, a small fire could cause a large amount of damage. NASA uses upward flame spread as a "worst case scenario" evaluation for materials and the Heat and Visible Smoke Release Rates Test to assess the damage potential of a fire. Details of these tests and the protocols followed are provided by the "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion" document. As pointed by Ohlemiller and Villa, the upward flame spread test does not address the effect of external radiation on ignition and spread. External radiation, as that coming from an overheated electrical component, is a plausible fire scenario in a space facility and could result in a reversal of the flammability rankings derived from the upward flame spread test. The "Upward Flame Propagation Test" has been the subject of strong criticism in the last few years. In many cases, theoretical exercises and experimental results have demonstrated the possibility of a reversal in the material flammability rankings from normal to micro-gravity. Furthermore, the need to incorporate information on the effects of external radiation and opposed flame spread when ranking materials based on their potential to burn in micro-gravity has been emphasized. Experiments conducted in a 2.2 second drop tower with an ethane burner in an air cross flow have emphasized that burning at the trailing edge is deterred in micro-gravity due to the decreased oxygen transport. For very low air flow velocities (U<0.005 m/s) the flame envelopes the burner and a slight increase in velocity results in extinction of the trailing edge (U>0.01 m/s). Only for U>0.l m/s extinction is observed at the leading edge (blow-off). Three dimensional numerical calculations performed for thin cellulose centrally ignited with an axisymmetric source have shown that under the presence of a forced flow slower than 0.035 m/s flames spreads only opposing the flow. Extinction is observed at the trailing edge with no concurrent propagation. Experiments conducted by the same authors at the JAMIC 10 second drop tower verified these calculations. Reducing the oxygen supply to the flame also results in a decrease of the Damk6hler number which might lead to extinction. Greyson et al. and Ferkul conducted experiments in micro-gravity (5 second drop tower) with thin paper and observed that at very low flow velocities concurrent flame spread will stop propagating and the flame will reduce in size and extinguish. They noted that quenching differs significantly from blow-off in that the upstream leading edge will remain anchored to the burn out edge.
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- 1999
25. Flow Effects on the Flammability Diagrams of Solid Fuels
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Cordova, J. L, Ceamanos, J, Fernandez-Pello, A. C, Long, R. T, Torero, J. L, and Quintiere, J. G
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Inorganic And Physical Chemistry - Abstract
A research program is currently underway with the final objective of developing a fundamental understanding of the controlling mechanisms underlying the flammability diagrams of solid combustible materials and their derived fire properties. Given that there is a high possibility of an accidental fire occurring in a space-based facility, understanding the fire properties of materials that will be used in such facilities is of critical importance. With this purpose, the flammability diagrams of the materials, as those produced by the Lateral Ignition and Flame Spread Test (LIFT) apparatus and by a new forced flow device, the Forced Flow Ignition and Flame Spread Test (FIST) apparatus, will be obtained. The specific objective of the program is to apply the new flammability apparatus, which will more accurately reflect the potential ambient conditions of space-based environments, to the characterization of the materials for space applications. This paper presents a parametric study of oxidizer flow effects on the ignition curve of the flammability diagrams of PMMA. The dependence of the ignition delay time on the external radiant flux and either the sample width (LIFT) or the flow velocity (FIST) has been studied. Although preliminary, the results indicate that natural and forced convection flow changes, affect the characteristics of the ignition curves of the flammability diagrams. The major effect on the ignition time appears to be due to convective transfer variations at the fuel surface. At high radiant fluxes or high flow velocities, however, it appears that gas phase processes become increasingly important, affecting the overall ignition delay time. A numerical analysis of the solid fuel heating and pyrolysis has also been developed. The theoretical predictions approximate the experiments well for conditions in which the gas phase induction time is negligible.
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- 1997
26. On the effect of pressure, oxygen concentration, air flow and gravity on simulated pool fires
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Torero, J. L, Most, J. M, and Joulain, P
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Inorganic And Physical Chemistry - Abstract
The initial development of a fire is characterized by the establishment of a diffusion flame over the surface of a the condensed fuel and is particularly influenced by gravity, with most of the gaseous flow induced by natural convection. Low initial momentum of the fuel vapor, strong buoyant flows induced by the hot post-combustion gases and consequently low values of the Froude number (inertia-gravity forces ratio) are typical of this kind of scenario. An experimental study is conducted by using a porous burner to simulate the burning of a horizontal combustible surface. Ethane is used as fuel and different mixtures of oxygen and nitrogen as oxidizer. The magnitude of the fuel injection velocities is restricted to values that will keep the Froude number on the order of 10-5, when calculated at normal gravity and pressure, which are characteristic of condensed fuel burning. Two different burners are used, a circular burner (62 mm diameter) placed inside a cylindrical chamber (0.3 m diameter and 1.0 m height) and a rectangular burner (50 mm wide by 200 mm long) placed in a wind tunnel (350 mm long) of rectangular cross section (120 mm wide and 90 mm height). The first burner is used to study the effect of pressure and gravity in the absence of a forced flow parallel to the surface. The second burner is used to study the effect of a forced flow parallel to the burner surface as well as the effect of oxygen concentration in the oxidizer flow. In this case experiments are also conducted at different gravity levels (micro-gravity, 0.2 g(sub 0), g(sub 0) and 1.8 g(sub 0)) to quantify the relative importance of buoyancy.
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- 1995
27. Experimental observations of the effect of gravity changes on smoldering combustion
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Torero, J. L, Fernandez-Pello, A. C, and Urban, D
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Inorganic And Physical Chemistry - Abstract
An experimental study is conducted to determine the effect of gravity changes on the natural convection smolder characteristics of flexible polyurethane foam. Gravity, and consequently buoyancy, is expected to affect smoldering because it induces convective transport of mass and heat to and from the reaction zone. The overall objective of the work is to provide information about the potential onset of a smolder-initiated fire in a space-based facility. Experiments are conducted in an aircraft following parabolic trajectories that provide up to 25 s of low gravity (KC-135A) and up to 20 s (Learjet Model 25), with a pull-up and pull-out of approximately 2 g per parabola. Measurements are performed, during a series of parabolas, of the temperature histories of the polyurethane foam at several locations along the fuel sample interior, both for upward and downward propagation. The measurements show that gravity plays a significant role in the competition between the supply of oxidizer to, and the transfer of heat to and from, the reaction zone.
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- 1994
28. Experimental Observations of the Effect of Gravity Changes on Smoldering Combustion
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Torero, J. L, Fernandez-Pello, A. C, and Urban, D
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Inorganic And Physical Chemistry - Abstract
The effects of gravity changes on the natural convection smolder characteristics of flexible polyurethane foam were determined in order to provide information on the potential onset of a smolder-initiated fire in a space-based facility. Experiments were conducted in an aircraft following parabolic trajectories providing up to 25 seconds of low gravity. Temperature histories of polyurethane foam were measured at several locations along the fuel sample interior. Results are presented and discussed for both upward and downward smoldering. Results indicate that gravity significantly effects the competition between supply of oxidizer to, and the transfer of heat to and from the reaction zone. This competition determines the characteristics of the smolder reaction. Within the reaction zone the reduction in oxygen supply in low gravity is dominant and the reaction weakens. Away from the reaction zone the reduction in convective cooling at low gravity tends to increase the material temperature. The opposite was observed at high gravity.
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- 1993
29. Dielectric spectroscopy of artificial faeces for smouldering applications
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Satie, Cachan, Bore, Thierry, Placko, D., Taillade, Frédéric, Sabouroux, P., Himbert, Marc, Wagner, Norman, Delepine Lesoille, Sylvie, Six, Gonzague, Daout, Franck, Lesoille-Delepine, S., Lynch, Jerome, Yun, Chung-Bang, Wang, Kon-Well, Yerman, L., Serna, M. Llano, Wall, H., Torero, J., Scheuerman, A., Laboratoire commun de métrologie LNE-CNAM (LCM), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE )-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Central des Ponts et Chaussées (LCPC), HIPE (HIPE), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Agence Nationale pour la Gestion des Déchets Radioactifs (ANDRA), Département Mesure, Auscultation et Calcul Scientifique (LCPC/MACS), Groupe d'Electromagnétisme Appliqué (GEA), Université Paris Nanterre (UPN), BRE / Centre for fire safety engineering, University of Edinburgh, Laboratoire Central des Ponts et Chaussées (LCPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
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Smouldering ,Permittivity ,Materials science ,Electromagnetics ,0211 other engineering and technologies ,02 engineering and technology ,Dielectric ,Network analyzer (electrical) ,01 natural sciences ,Dielectric spectroscopy ,010309 optics ,[SPI]Engineering Sciences [physics] ,0103 physical sciences ,Composite material ,Porous medium ,Water content ,ComputingMilieux_MISCELLANEOUS ,021101 geological & geomatics engineering - Abstract
Our objective is to develop an analysis concept in order to measure the in situ estimation of state parameter, such as water content, during smouldering of waste and sand mixtures. High frequency electromagnetic (HF EM) method presents a high potential for the quantitative estimation of state parameter in porous media. However, it provides indirect measurement: the major challenge is to derive robust relationship between the performed measured permittivity and the parameter under interest. Thus, laboratory measurement of dielectric properties of waste and sand mixtures under controlled boundary are urgently needed. In this preliminary study, the relative effective complex permittivity of artificial faeces was studied over the 50°MHz–3°GHz frequency range with network analyzer technique in combination with homemade open ended coaxial method. In a first step, the effect of water content on dielectric properties was investigated. The results have shown an important dispersion for the imaginary part which can be related to interface process and a systematic increase of the permittivity with water content. In a second step, a shrinking test was monitored with the homemade probe. The relative complex permittivity shows a nonlinear evolution with gravimetric water content and show marked transitions during the decrease of water content. The results of combined investigations have shown the potential of HF EM techniques for quantitative monitoring of the hydraulic state of waste and sand mixtures during smouldering combustion.
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- 2016
30. Potential Bio-oil Production from Smouldering Combustion of Faeces
- Author
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Yermán, L., primary, Cormier, D., additional, Fabris, I., additional, Carrascal, J., additional, Torero, J. L., additional, Gerhard, J. I., additional, and Cheng, Y.-L., additional
- Published
- 2016
- Full Text
- View/download PDF
31. Dielectric spectroscopy of artificial faeces for smouldering applications
- Author
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Bore, T., primary, Yerman, L., additional, Serna, M. Llano, additional, Wall, H., additional, Torero, J. L., additional, and Scheuerman, A., additional
- Published
- 2016
- Full Text
- View/download PDF
32. Smoldering Combustion as a Treatment Technology for Feces: Sensitivity to Key Parameters
- Author
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Yermán, L., primary, Wall, H., additional, Torero, J., additional, Gerhard, J. I., additional, and Cheng, Y.-L., additional
- Published
- 2016
- Full Text
- View/download PDF
33. Comparison of experimental and calculated tensile properties of flax fibres
- Author
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Torero, J, Fernando, D, Teng, J-G, Soatthiyanon, N, Crosky, A, Torero, J, Fernando, D, Teng, J-G, Soatthiyanon, N, and Crosky, A
- Abstract
The tensile properties of natural plant fibres are commonly determined by single fibre testing. The cross- sectional area used to determine the modulus and strength is usually obtained by measuring the fibre width and using this as the fibre diameter on the assumption that the fibres are circular in section. While the assumption of circularity is reasonably true for synthetic fibres, it is not correct for natural fibres and this can lead to substantial error when determining the tensile properties of the fibres. The present study determined the tensile properties of 113 flax technical fibres using an experimentally determined fibre area correction factor to account for the non-circularity of the fibres. The data was then compared with that obtained from back-calculation of the results obtained from longitudinal tensile testing of flax/vinyl ester unidirectional composites manufactured from the same material as that used for the single fibre tests. Account was taken of the effect of fibre length on strength. The experimentally determined fibre area correction factor was found to be 2.70. Taking this into account for the single fibre tests, the back-calculated modulus of the flax fibres was within 6% of that obtained from the single fibre tests while the strength was within 7%.
- Published
- 2015
34. Elementary kenaf fibre extraction
- Author
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Torero, J, Fernando, D, Teng, J-G, Soatthiyanon, N, Crosky, A, Torero, J, Fernando, D, Teng, J-G, Soatthiyanon, N, and Crosky, A
- Abstract
Elementary kenaf fibres were separated by the HNO3 treatment and the H2O2/CH3COOH treatment. It was found that the HNO3 treatment caused fibre fragmentation causing a decrease in the fibre length and an increase in the fibre defect density. However, the H2O2/CH3COOH treatment was not strong as the HNO3 treatment and this had much less effect on the fibre length and the fibre defects. The fibres had an average length of 0.2 mm and 2.3 mm and an aspect ratio of 15 and 179 for the HNO3 treated fibres and the H2O2/CH3COOH treated fibres, respectively. The defect density of the HNO3 treated fibres and the H2O2/CH3COOH treated fibres was 21 and 14 defects/mm, respectively. Both the treatments removed lignin, pectin and waxes. They also increased cellulose crystallinity in the fibres, especially for the HNO3 treatment. However, these treatments resulted in some oxidation of cellulose to occur.
- Published
- 2015
35. AFRP retrofit of reinforced concrete columns against impact loading
- Author
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Teng, J G, Torero, J L, Fernando, D, Gurbuz, Tuba, Ilki, Alper, Thambiratnam, David, Perera, Nimal, Teng, J G, Torero, J L, Fernando, D, Gurbuz, Tuba, Ilki, Alper, Thambiratnam, David, and Perera, Nimal
- Abstract
Structures can be exposed to impact loads as a result of an explosion, falling objects, projectiles and vehicle collisions. Within the increasing threat of these impact sources, it is very important to protect the columns that are the vital members of the structural systems to ensure structural and personal safety. This study focuses on the performance of axially loaded reinforced concrete members subjected to impact loading. A dropped-weight test set-up developed to perform impact tests on reinforced concrete members. The test set-up was used to perform low elevation impact tests on reinforced concrete (RC) columns that targets to simulate vehicular impact against ground floor columns of low-rise buildings. Since, there is limited information about the transverse impact performances of RC columns; the main objective of this research is to assess the vulnerability of RC columns under transverse impact loads and to enhance their performances by using Aramid Fiber Reinforced Polymer (AFRP) sheets. The scope is limited to 300 mm square columns with 3 m height in low to medium rise buildings which were found to be more vulnerable to lateral impacts according to previous research conducted by the authors, (Gurbuz et al. 2010, 2011). This research provides fundamental knowledge on the behavior of RC columns under low elevation impact loading and also generates new information on impact strengthening of vulnerable concrete columns by AFRP sheets.
- Published
- 2015
36. Effect of layer variations on CFRP strengthened steel circular hollow members under bending: Numerical studies
- Author
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Teng, J G, Torero, J L, Fernando, D, Kabir, Md, Fawzia, Sabrina, Chan, Tommy, Batuwitage, Chamila Rajeev Jayanath, Teng, J G, Torero, J L, Fernando, D, Kabir, Md, Fawzia, Sabrina, Chan, Tommy, and Batuwitage, Chamila Rajeev Jayanath
- Abstract
The number of carbon fibre reinforced polymer (CFRP) layer and their orientation generally affect the strength and stiffness of the steel circular hollow section (CHS) members primarily when they are subjected to bending. In this study, numerical investigation is carried out to find the effect of number and orientation of CFRP composites layer on strength and stiffness of CHS members under bending. In numerical investigation, cohesive element is adopted to model interface element (adhesive) and an 8-node quadrilateral in-plane general-purpose continuum shell is used to model CFRP elements. The validity of the FE models is ascertained by comparing the ultimate load, stiffness and failure mode from experimental results. The results of FE analyses show that the strength and stiffness increase with the increase of number of CFRP layer. The three layer configured CFRP strengthened steel CHS beams are found cost effective with respect to strength increment than four layer configured CFRP strengthened steel CHS beams
- Published
- 2015
37. Experimental and numerical studies of hollow flange channel beams subject to web crippling under ETF and ITF load cases
- Author
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Teng, J G, Torero, J L, Fernando, D, Poologanathan, Keerthan, Mahendran, Mahen, Steau, Edward, Teng, J G, Torero, J L, Fernando, D, Poologanathan, Keerthan, Mahendran, Mahen, and Steau, Edward
- Abstract
This paper presents the details of experimental and numerical studies on the web crippling behaviour of hollow flange channel beams, known as LiteSteel beams (LSB). The LSB has a unique shape of a channel beam with two rectangular hollow flanges, made using a unique manufacturing process. Experimental and numerical studies have been carried out to evaluate the behaviour and design of LSBs subject to pure bending actions, predominant shear actions and combined actions. To date, however, no investigation has been conducted into the web crippling behaviour and strength of LSB sections under ETF and ITF load conditions. Hence experimental studies consisting of 28 tests were first conducted in this research to assess the web crippling behaviour and strengths of LSBs under two flange load cases (ETF and ITF). Experimental web crippling capacity results were then compared with the predictions from AS/NZS 4600 and AISI S100 design rules, which showed that AS/NZS 4600 and AISI S100 design equations are very unconservative for LSBs under ETF and ITF load cases. Hence improved equations were proposed to determine the web crippling capacities of LSBs. Finite element models of the tested LSBs were then developed, and used to determine the elastic buckling loads of LSBs under ETF and ITF load cases. New equations were proposed to determine the corresponding elastic buckling coefficients of LSBs. Finally suitable design rules were also developed under the Direct Strength Method format using the test results and buckling analysis results from finite element analyses.
- Published
- 2015
38. Bond characteristics of strengthened and retrofitted steel by smart CFRP technique
- Author
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Teng, J G, Torero, J L, Fernando, D, Batuwitage, Chamila Rajeev Jayanath, Fawzia, Sabrina, Liu, Xuemei, Thambiratnam, David, Alam, Md Iftekharul, Teng, J G, Torero, J L, Fernando, D, Batuwitage, Chamila Rajeev Jayanath, Fawzia, Sabrina, Liu, Xuemei, Thambiratnam, David, and Alam, Md Iftekharul
- Abstract
Usage of new smart materials in retrofitting of structures has become popular within last decade. Carbon fiber reinforced polymer (CFRP) has been widely used in retrofitting and strengthening of concrete structures and its usage in metallic structures is still in the developing stage. The variation of mechanical properties of CFRP and the consequent effects on strengthening and retrofitting CFRP systems are yet to be investigated under different loading and environmental conditions. This paper presents the results of CFRP strengthened and retrofitted corroded steel plate double strap joints under tension. An accelerated corrosion cell has been developed to accelerate the corrosion of the steel samples and CFRP strengthened samples. The results show a direct comparison of bond characteristics of CFRP strengthened and retrofitted steel double strap joints.
- Published
- 2015
39. Numerical studies of gypsum plasterboard and MGO board lined LSF walls exposed to fire
- Author
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Teng, J G, Torero, J L, Fernando, D, Mohamed Ibralebbe, Mohamed Rusthi, Poologanathan, Keerthan, Ariyanayagam, Anthony, Mahendran, Mahen, Teng, J G, Torero, J L, Fernando, D, Mohamed Ibralebbe, Mohamed Rusthi, Poologanathan, Keerthan, Ariyanayagam, Anthony, and Mahendran, Mahen
- Abstract
Fire resistance of cold-formed light gauge steel frame (LSF) wall systems is enhanced by lining them with single or multiple layers of wall boards with varying thermal properties. These wall boards are gypsum plasterboards or Magnesium Oxide (MgO) boards produced by different manufacturers. Thermal properties of these boards appear to show considerable variations and this can lead to varying fire resistance levels (FRL) for their wall systems. Currently FRLs of wall systems are determined using full scale fire tests, but they are time consuming and expensive. Recent research studies on the fire performance of LSF wall systems have used finite element studies to overcome this problem, but they were developed based on 1-D and 2-D finite element platform capable of performing either heat transfer or structural analysis separately. Hence in this research a 3-D finite element model was developed first for LSF walls lined with gypsum plasterboard and cavity insulation materials. Accurate thermal properties of these boards are essential for finite element modelling, and thus they were measured at both ambient and elevated temperatures. This experimental study included specific heat, relative density and thermal conductivity of boards. The developed 3-D finite element model was then validated using the available fire tests results of LSF walls lined with gypsum plasterboard, and is being used to investigate the fire performance of different LSF wall configurations. The tested MgO board exhibited significant variations in their thermal properties in comparison to gypsum plasterboards with about 50% loss of its initial mass at about 500 ºC compared to 16% for gypsum plasterboards. Hence the FRL of MgO board lined LSF wall systems is likely to be significantly reduced. This paper presents the details of this research study on the fire performance of LSF wall systems lined with gypsum plasterboard and MgO board including the developed 3-D finite element models, thermal property
- Published
- 2015
40. Fire resistance of light gauge steel frame wall systems lined with gypsum plasterboards
- Author
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Teng, J G, Torero, J L, Fernando, D, Ariyanayagam, Anthony, Mahendran, Mahen, Teng, J G, Torero, J L, Fernando, D, Ariyanayagam, Anthony, and Mahendran, Mahen
- Abstract
Light gauge steel frame (LSF) wall systems are increasingly used in residential and commercial buildings as load bearing and non-load bearing elements. Conventionally, the fire resistance ratings of such building elements are determined using approximate prescriptive methods based on limited standard fire tests. However, recent studies have shown that in some instances real building fire time-temperature curves could be more severe than the standard fire curve, in terms of maximum temperature and rate of temperature rise. This has caused problems for safe evacuation and rescue activities, and in some instances has also lead to the collapse of buildings earlier than the prescribed fire resistance. Therefore a detailed research study into the performance of LSF wall systems under both standard fire and realistic fire conditions was undertaken using full scale fire tests to understand the fire performance of different LSF wall configurations. Both load bearing and non-load bearing full scale fire tests were performed on LSF walls configurations which included single layer, double layer, externally insulated wall panels made up of different steel sections and thicknesses of gypsum plasterboards. The non-load bearing fire test results were utilized to understand the factors affecting the fire resistance of LSF walls, while loading bearing fire test results led to development of simplified methods to predict the fire resistance ratings of load bearing LSF walls exposed to both standard and realistic design fires. This paper presents the results of full scale experimental study and highlights the effects of standard and realistic fire conditions on fire performance of LSF walls.
- Published
- 2015
41. CFRP strengthened CFST columns under vehicular impact
- Author
-
Teng, J G, Torero, J L, Fernando, D, Alam, Md Iftekharul, Fawzia, Sabrina, Batuwitage, Chamila Rajeev Jayanath, Teng, J G, Torero, J L, Fernando, D, Alam, Md Iftekharul, Fawzia, Sabrina, and Batuwitage, Chamila Rajeev Jayanath
- Abstract
Concrete filled steel tubular (CFST) columns are increasingly used in bridge piers and high-rise buildings due to their excellent axial load bearing capacity. These columns may experience severe damage or failure due to transverse impact of vehicle collisions. In this study, numerical investigation is carried out to evaluate the effect of carbon fibre reinforced polymer (CFRP) strengthening CFST columns under vehicular impact. The CFRP composites damage mechanisms are simulated to account four different failure criteria. The cohesive elements are introduced as interface element to properly simulate the adhesively bonded regime. Simplified vehicle model is also developed to represent real vehicle behaviour. The FE analysis results show that externally bonded CFRP composites improve the impact resistance capacity compared to bare CFST column.
- Published
- 2015
42. Time-dependent Multiscale Simulations of Fire Emergency in longitudinally ventilated tunnels
- Author
-
Colella, Francesco, Rein, G., Verda, Vittorio, Borchiellini, Romano, and Torero, J. L.
- Subjects
tunnel fires ,smoke management ,detection ,multiscale modeling ,CFD - Published
- 2011
43. Modelado de las solicitaciones de los elementos estructurales de hormigón en edificios de gran altura en incendios reales
- Author
-
Capote Abreu, J. A., Alvear, D., Lázaro, M., Crespo, J., Fletcher, I., Welch, S., and Torero, J.
- Subjects
thermal loads ,modelado CFD ,solicitaciones térmicas ,CFD modelling ,structural behaviour ,propagación interior ,respuesta estructural ,fire spread ,room fires ,incendios en recintos cerrados - Abstract
The fire of the Windsor Building in Madrid represents a paradigm in High Rise Building Fires. The present Work analyzes the origin, growth and propagation conditions of natural fires in tall buildings. The Study has been focused on the determination of the thermal exposure conditions (temperatures T, heat fluxes q,,, etc.) on the structural members of high rise buildings, at end use conditions, under natural fires using fire computer modeling techniques. Work allowed: 1) validate the predictive capacity of the fluid-dynamics computer models used, 2) apply these models to a specific fire scenario to assess the thermal and the mechanical response of the structural members of a high rise building. El incendio de la Torre Windsor de Madrid constituye un suceso paradigmático de incendios en edificios de gran altura. En el presente Estudio se analizan las condiciones de origen, desarrollo y propagación de incendios reales en este tipo de edificaciones, así como la determinación de las condiciones de exposición (temperaturas T , flujos de calor q,, etc.) a las que se encuentran sometidos los elementos estructurales, en condiciones de uso final en este tipo de estructuras, mediante la utilización de técnicas de modelado y simulación computacional de incendios. Los trabajos realizados, se centraron en aquellas actuaciones que: 1) permitieran validar la capacidad predictiva de los modelos de fluido-dinámica empleados, 2) la aplicación de los modelos ajustados y validados a un escenario de incendio en condiciones de uso final en un edificio de gran altura, para la predicción de la respuesta mecánica de la trama estructural.
- Published
- 2011
- Full Text
- View/download PDF
44. Towards optimizing thermal performance of prefabricated houses in Australian climates
- Author
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Soret, G. M., primary, Tonino, J., additional, Torero, J. L., additional, and Aitchison, M., additional
- Published
- 2015
- Full Text
- View/download PDF
45. Tunnel ventilation effectiveness in fire scenarios
- Author
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Colella, Francesco, Rein, G, Carvel, R, and Torero, J. L.
- Subjects
ventilation ,Tunnel Fire ,multiscale modelling ,CFD ,Ventilation ,tunnel ,fire - Abstract
Article on the FS-World Magazine special Edition on Tunnel Safety (4th International Symposium on Tunnel Safety and Security Frankfurt, March, 2010) Throughout most of a tunnel network the ventilation behaviour may be approximated with a simple 1D flow model. However, there are some important - but relatively small - regions of the tunnel that require CFD analysis. The multi-scale model is the ideal tool for such tunnel studies as it allows accurate flow field predictions in some locations, yet allows simplifications where highly detailed data are not required. It is shown that the accuracy of the multi-scale model is as high as the full CFD approach. The 100 times lower computational time is of great advantage because many ventilation scenarios can be explored and extensive sensitive parametric studies can be conducted.
- Published
- 2010
46. Flaming Ignition of Pine Needle Beds
- Author
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Colella, Francesco, BARTOLI P, MARTINOT E., and Torero, J. L.
- Subjects
Wildland fires ,porous bed fuels ,ignition - Published
- 2010
47. Design of Tunnel Ventilations Systems for Fire Emergencies using Multiscale Modelling
- Author
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Colella, Francesco, Borchiellini, Romano, Carvel, R, Rein, G, Steinhaus, T, Torero, J. L., and Verda, Vittorio
- Subjects
tunnel fire ,smoke dynamics ,multiscale modelling ,CFD - Published
- 2010
48. Analysis of the ventilation systems in the Dartford Tunnels using multi-scale modelling approach
- Author
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Colella, Francesco, Rein, G, Carvel, R, Reszka, P, Steinhaus, T, and Torero, J. L.
- Subjects
jet fans ,mutliscale modelling ,Dartford Tunnels ,ventilation systems ,CFD - Published
- 2009
49. Approximate Travelling Distances of water mist droplets in tunnels
- Author
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Cavallo, A, Crosfield, R, Colella, Francesco, Carvel, R, Rein, G, and Torero, J. L.
- Subjects
tunnel fire ,droplet trajectories ,water mist - Published
- 2009
50. Determination of Fire Induced Collapse Mechanisms of Multi-Storey Steel Framed Structures - A Case Study
- Author
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Torero, J. L., Usmani, A. S., Lane, B., and Lamont, S.
- Published
- 2005
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