The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Tarek Beji - One of the best experts on this subject based on the ideXlab platform.
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Improved Assessment of Fire Spread over Horizontal Cable Trays Supported by Video Fire Analysis
Fire Technology, 2019Co-Authors: Pascal Zavaleta, Romain Hanouzet, Tarek BejiAbstract:Fire safety analyses in nuclear power plants need to assess the heat release rate (HRR) of potential Cable fires. This study deals with the FLASH-CAT model which assesses the HRR of a fire spreading over horizontal ladder Cable Trays. As part of the OECD PRISME-2 project, fire tests which involved horizontal Trays supported by a wall, highlighted fast fire growth and large HRR peak. This study investigated the ability of the FLASH-CAT model to predict the HRR for such configuration. The first assessments of the PRISME-2 tests with the FLASH-CAT model significantly delayed the ignition and under-estimated the fire growth rate and the HRR peak. A video fire analysis method was developed and contributed to propose updated input parameters, such as the ignition time and the horizontal spread rate, for Cable tray configurations with a wall. In addition, modifications in the model which affect the burning Cable tray area and the local fire duration are also discussed. The assessments of the PRISME-2 experiments with the modified FLASH-CAT model and the proposed input parameters are consistent with the measured HRR. In addition, the modified model also gives acceptable predictions of the HRR for numerous tests of the CHRISTIFIRE programme.
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Improved Assessment of Fire Spread over Horizontal Cable Trays Supported by Video Fire Analysis
Fire Technology, 2019Co-Authors: P. Zavaleta, Romain Hanouzet, Tarek BejiAbstract:Fire safety analyses in nuclear power plants need to assess the heat release rate (HRR) of potential Cable fires. This study deals with the FLASH-CAT model which assesses the HRR of a fire spreading over horizontal ladder Cable Trays. As part of the OECD PRISME-2 project, fire tests which involved horizontal Trays supported by a wall, highlighted fast fire growth and large HRR peak. This study investigated the ability of the FLASH-CAT model to predict the HRR for such configuration. The first assessments of the PRISME-2 tests with the FLASH-CAT model significantly delayed the ignition and under-estimated the fire growth rate and the HRR peak. A video fire analysis method was developed and contributed to propose updated input parameters, such as the ignition time and the horizontal spread rate, for Cable tray configurations with a wall. In addition, modifications in the model which affect the burning Cable tray area and the local fire duration are also discussed. The assessments of the PRISME-2 experiments with the modified FLASH-CAT model and the proposed input parameters are consistent with the measured HRR. In addition, the modified model also gives acceptable predictions of the HRR for numerous tests of the CHRISTIFIRE programme. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
Choong Heui Jeong - One of the best experts on this subject based on the ideXlab platform.
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Electrostatic Analysis of a Short Accident in Cable Trays for Intelligent Pressure Transmitters
IU-Journal of Electrical & Electronics Engineering, 2016Co-Authors: Jaeyul Choo, Hyung Tae Kim, Hyun Shin Park, Choong Heui JeongAbstract:We apply the mode-matching method to the electrostatic analysis of shorted enclosed-Cable Trays that are generally used in industrial facilities such as a nuclear power plant. In mode-matching formulation on potential distribution, we utilize Laplace’s equation and superposition principle. After obtaining the modal coefficients from Dirichlet and Neumann boundary conditions, we then derive distributions of potential and electric field, capacitance matrix, effecive didlectric constant, and characteristic impedance to evaluate the electromagnetic influence caused by a short accident in the enclosed-Cable tray.
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Electrostatic analysis of a short accident in Cable Trays for intelligent pressure transmitters
2015 9th International Conference on Electrical and Electronics Engineering (ELECO), 2015Co-Authors: Jaeyul Choo, Sang Yong Jeong, Hyung Tae Kim, Hyun Shin Park, Choong Heui JeongAbstract:We apply the mode-matching method to the electrostatic analysis of shorted enclosed-Cable Trays that are generally used in industrial facilities such as nuclear power plants. In mode-matching formulation on the potential distribution, we utilize Laplace's equation and superposition principle. After obtaining modal coefficients from Dirichlet and Neumann boundary conditions, we then derive the potential and electric field distributions and the capacitance matrices to evaluate the electromagnetic influence due to a short accident.
Pascal Zavaleta - One of the best experts on this subject based on the ideXlab platform.
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Horizontal Cable Trays fire in a well‐confined and mechanically ventilated enclosure using a two‐zone model
Fire and Materials, 2019Co-Authors: William Plumecocq, Laurent Audouin, Pascal ZavaletaAbstract:Electrical Cable Trays are used in large quantities in nuclear power plants (NPPs) and are one of the main potential sources of fire. A malfunction of electrical equipment due to thermal stress for instance may lead to the loss of important safety functions of the NPPs. The investigation of such fires in a confined and mechanically ventilated enclosure has been scarce up to now and has been investigated in the nuclear industry. In the scope of the OECD PRISME-2 project, the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) conducted more than a dozen of fire tests involving horizontal electrical Cable Trays burning either in open atmosphere under a calorimetric hood or inside mechanically ventilated compartments to investigate this topic. Calorimetric hood experiments in open atmosphere highlighted that the halogenated flame retardant Cable tests had shorter ignition time, faster fire growth rate and higher peak of Heat Release Rate (HRR), compared with the mineral flame retardant Cables tested. The influence of the enclosure on the fire behavior depends on the temperature of the surrounding gas of the Cables, as well as on the oxygen content at the level of Cables. The enclosure strongly impacts the pyrolysis of the fuel, decreasing the mass loss rate and the HRR of the fuel, affecting the fire duration. For tests performed at low ventilation level, combustion of unburned gases occurred due to a high production of pyrolysed gas in excess. A semi-empirical model of horizontal Cable Trays fires in a well-confined enclosure was developed. This model is partly based on the approach used in FLASH-CAT and on experimental findings from the IRSN Cables fire tests. It was implemented in the two-zone model SYLVIA. The major features of the compartment fire experiments, such as characteristic HRR and fire duration, could then be reproduced with acceptable error, except for combustion of unburned gases, occurring in the upper part of the fire compartment. The development of such a semi-empirical model is a common practice in fire safety engineering concerned with complex solid fuels.
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Improved Assessment of Fire Spread over Horizontal Cable Trays Supported by Video Fire Analysis
Fire Technology, 2019Co-Authors: Pascal Zavaleta, Romain Hanouzet, Tarek BejiAbstract:Fire safety analyses in nuclear power plants need to assess the heat release rate (HRR) of potential Cable fires. This study deals with the FLASH-CAT model which assesses the HRR of a fire spreading over horizontal ladder Cable Trays. As part of the OECD PRISME-2 project, fire tests which involved horizontal Trays supported by a wall, highlighted fast fire growth and large HRR peak. This study investigated the ability of the FLASH-CAT model to predict the HRR for such configuration. The first assessments of the PRISME-2 tests with the FLASH-CAT model significantly delayed the ignition and under-estimated the fire growth rate and the HRR peak. A video fire analysis method was developed and contributed to propose updated input parameters, such as the ignition time and the horizontal spread rate, for Cable tray configurations with a wall. In addition, modifications in the model which affect the burning Cable tray area and the local fire duration are also discussed. The assessments of the PRISME-2 experiments with the modified FLASH-CAT model and the proposed input parameters are consistent with the measured HRR. In addition, the modified model also gives acceptable predictions of the HRR for numerous tests of the CHRISTIFIRE programme.
Xianjia Huang - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation on maximum ceiling jet temperature generated by a vertically spreading Cable fire
Fire Safety Journal, 2020Co-Authors: Xianjia Huang, Yuhong Wang, Zhaoying Ren, Chihonn Cheng, Wan Ki ChowAbstract:Abstract Maximum ceiling jet temperature (MCJT) is an important parameter for evaluating fire risk. An important characteristic of vertical Cable tray fire is the upward spreading of the Cable flame along the Cable tray, which leads to a decrease in the distance between the fire source and compartment ceiling during such a fire. Thus, full-scale fire experiments using vertical Cable Trays were conducted in a confined compartment to investigate the MCJT. The upward spreading of the Cable flame leads to transition of the MCJT dominated by the plume region to intermittent region of the flame. In particular, it is observed that the MCJT suddenly increases from ~200 °C to more than 600 °C at this transition point. Taking the upward spreading Cable flame along the vertical Cable tray as a point fire source moving with constant velocity, a modified model is proposed to estimate the MCJT. Prediction using the proposed modified model yields promising results. The local prediction error for the modified model is less than 12%, and the global prediction error is between 23.6% and 38.6%. These errors are significantly lower than those for other models that assume a fixed fire source.
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Experimental and Numerical Simulation Study on Multilayer Cable Trays Fire Under Mechanically Ventilated Conditions
Proceedings of The 20th Pacific Basin Nuclear Conference, 2017Co-Authors: Xianjia Huang, Bi Kun, Liu XiaoshuangAbstract:The performance-based standard for fire protection was first proposed for light water reactor electric generating plants in NFPA-805. The zone model is considered as a main option for fire safety analysis in nuclear power plant. Cable fire is one of the most common hazards in nuclear power plant. The structure of multilayer Cable Trays fire is a challenge for simulation by zone model. At the same time, the mechanical ventilation has significant effects on the fire process. Therefore, the focus of this paper is to investigate the reliability of zone model software simulating the multilayer Cable Trays fire under mechanical ventilation. Fire experiments of four-layer Cable Trays were conducted in a confined room with mechanical ventilation. The mass loss rate of Cable Trays, the ceiling jet temperature, and the vertical temperature distribution in the room were recorded during the Cable burning. According to the measured vertical temperature profile under mechanical ventilation, it is found that the fire room can be divided into upper hot layer and lower cool layer, which is conformed to the basic assumption for two-zone model. Therefore, the zone fire model CFAST (Consolidated Model of Fire Growth and Smoke Transport), was used to simulate the multilayer Cable Trays fire under mechanical ventilation. Comparing the predicted ceiling jet and upper layer temperatures with experimental data, it is shown that CFAST has good prediction on multilayer Cable Trays fire under mechanical ventilation. By setting each layer of Cable tray as one fire source, CFAST can catch the burning characteristics of multiple-layer Cable tray fire.
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An enhanced fire hazard assessment model and validation experiments for vertical Cable Trays
Nuclear Engineering and Design, 2016Co-Authors: Xianjia Huang, Bi Kun, Liu XiaoshuangAbstract:Abstract The model, referred to as FLASH-CAT (Flame Spread over Horizontal Cable Trays), was developed to estimate the heat release rate for vertical Cable tray fire. The focus of this work is to investigate the application of an enhanced model to the single vertical Cable tray fires with different Cable spacing. The experiments on vertical Cable tray fires with three typical Cable spacing were conducted. The histories of mass loss rate and flame length were recorded during the Cable fire. From the experimental results, it is found that the space between Cable lines intensifies the Cable combustion and accelerates the flame spread. The predictions by the enhanced model show good agreements with the experimental data. At the same time, it is shown that the enhanced model is capable of predicting the different behaviors of Cable fires with different Cable spacing by adjusting the flame spread speed only.
Jaeyul Choo - One of the best experts on this subject based on the ideXlab platform.
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Interpretation on Electromagnetic Interference between Open Cable Trays
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019Co-Authors: Jaeyul Choo, Dong-jin LeeAbstract:This paper represents analytical interpretation on the electromagnetic interference between open Cable Trays of solid-bottom type in a nuclear power plant in assumption that the electric-line current is undesirably generated from damaged Cable in a Cable tray. Based on the superposition principle and Helmholtz's equation in conjunction with both the separation of variables, we employed the mode-matching method to obtain an analytical solution to this electromagnetic interference problem. Using the modal coefficients obtained from a set of simultaneous equations, we computationally derive electromagnetic-field distributions in terms of various geometric parameters. The investigated results provide us with the useful information to estimate that how much the undesired current source influences on the adjacent digital modules.
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Electrostatic Analysis of a Short Accident in Cable Trays for Intelligent Pressure Transmitters
IU-Journal of Electrical & Electronics Engineering, 2016Co-Authors: Jaeyul Choo, Hyung Tae Kim, Hyun Shin Park, Choong Heui JeongAbstract:We apply the mode-matching method to the electrostatic analysis of shorted enclosed-Cable Trays that are generally used in industrial facilities such as a nuclear power plant. In mode-matching formulation on potential distribution, we utilize Laplace’s equation and superposition principle. After obtaining the modal coefficients from Dirichlet and Neumann boundary conditions, we then derive distributions of potential and electric field, capacitance matrix, effecive didlectric constant, and characteristic impedance to evaluate the electromagnetic influence caused by a short accident in the enclosed-Cable tray.
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Electrostatic analysis of a short accident in Cable Trays for intelligent pressure transmitters
2015 9th International Conference on Electrical and Electronics Engineering (ELECO), 2015Co-Authors: Jaeyul Choo, Sang Yong Jeong, Hyung Tae Kim, Hyun Shin Park, Choong Heui JeongAbstract:We apply the mode-matching method to the electrostatic analysis of shorted enclosed-Cable Trays that are generally used in industrial facilities such as nuclear power plants. In mode-matching formulation on the potential distribution, we utilize Laplace's equation and superposition principle. After obtaining modal coefficients from Dirichlet and Neumann boundary conditions, we then derive the potential and electric field distributions and the capacitance matrices to evaluate the electromagnetic influence due to a short accident.
