An improved model for estimating heat release rate in horizontal cable tray fires in open space

2018 ◽  
Vol 36 (3) ◽  
pp. 275-290 ◽  
Author(s):  
Xianjia Huang ◽  
He Zhu ◽  
Lan Peng ◽  
Zihui Zheng ◽  
Wuyong Zeng ◽  
...  

Electric cable fires in nuclear power plants could be disastrous and have to be studied carefully for safety and economic considerations. Based on the results of previous work on large-scale and bench-scale cable fire testing, the Flame Spread over Horizontal Cable Trays model was modified and improved to estimate the heat release rate of large-scale cable fires using bench-scale measured data. The heat release rate per unit area measured in the cone calorimeter experiment is taken as the input, to avoid introducing any prediction uncertainties caused by inconsistent values of the heat of combustion and char yield of the cable. Cable fire experiments with vertical stacks of trays with one to three layers of cables were conducted in open space to assess the accuracy of the improved model. In comparing with the experimental results, predictions using the improved model are encouraging. The local error of prediction is less than 15% and the global error lies between 19.2% and 35.7%. In addition, three cable tray fire experiments with data available in the literature were used to validate the improved model. It is shown that the improved model had good predictions for these cable tray fires.

2020 ◽  
Vol 93 (5) ◽  
pp. 1901-1913 ◽  
Author(s):  
Francis O. Olanrewaju ◽  
Hu Li ◽  
Gordon E. Andrews ◽  
Herodotos N. Phylaktou

Author(s):  
Alexander J. De Rosa ◽  
Janith Samarasinghe ◽  
Stephen J. Peluso ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca

Fluctuations in the heat release rate that occur during unstable combustion in lean premixed gas turbine combustors can be attributed to velocity and equivalence ratio fluctuations. For a fully premixed flame, velocity fluctuations affect the heat release rate primarily by inducing changes in the flame area. In this paper, a technique to analyze changes in flame area using chemiluminescence-based flame images is presented. The technique decomposes the flame area into separate components which characterize the relative contributions of area fluctuations in the large scale structure and the small scale wrinkling of the flame. The fluctuation in the wrinkled area of the flame which forms the flame brush is seen to dominate its response in the majority of cases tested. Analysis of the flame area associated with the large scale structure of the flame resolves convective perturbations that move along the mean flame position. Results are presented that demonstrate the application of this technique to both single-nozzle and multi-nozzle flames.


2021 ◽  
Vol 21 (4) ◽  
pp. 49-59
Author(s):  
Oh Sang Kweon ◽  
Hyun Kang ◽  
Heung-Youl Kim

During an accidental fire in buildings, the corridor becomes the path for flame and smoke to spread, exposing the occupants to danger. Therefore, this study conducted real-scale fire experiments using corridors of size 2.4(L) × 10(W) × 2.4(H) m an “L-type” corridor for one-way evacuation and a “T-type” corridor for two-way evacuation to analyze the characteristics of fire according to the shape of corridors. The real-scale fire experiments were conducted in a fire room (2.4(L) × 3.6(W) × 2.4(H) m) with a single opening (2.0(W) × 1.8(H) m). The combustibles used inside the fire room were wood cribs, with a heat release rate of 651.4 kW, in the L-type corridor and chairs, with a heat release rate of 95.7 kW, in the T-type corridor. The temperature inside the corridor was measured during the real-scale fire experiments, and the average maximum measured temperature was 432.1 °C in the L-type corridor and 103.5 °C in the T-type corridor. The experimental results and the ventilation characteristics according to the corridor types were applied to BFD curves to show the process of designing fire growth models according to corridor types.


Author(s):  
Charles Luo ◽  
Soroush Yazdani ◽  
Brian Y. Lattimer

Large scale flammability performance of interior finish used on railcars has been evaluated in previous studies using the NFPA 286 room corner fire test, which has a cross-section similar to a railcar. In some studies, the wall containing the door was removed to account for the shorter length of the room compared to the railcar length. The focus of this study is to assess whether the NFPA 286 standard room-corner test with a door represents conditions that developed inside a railcar during a fire. Fire Dynamics Simulator (FDS) was used to model the fire growth in a NFPA 286 standard room-corner test with a door, NFPA 286 room without the wall containing the door, and railcar geometry with a single door open. All three cases had the same exposure fire in a corner and the same lining material. In predictions of the NFPA 286 room-corner test with a door, gas temperature, heat release rate, and time to flashover agreed well with available NFPA 286 standard test data. The simulation results of fire growth inside a railcar with one side door open produced similar conditions and fire growth compared with the standard NFPA 286 room with a door. For simulations on the NFPA 286 room with the wall containing the door removed, it was found that removal of the wall with the door resulted in non-conservative fire growth conditions with the gas temperature and heat release rate under-estimated compared to the standard NFPA 286 room with a door. These simulations indicate that the standard NFPA 286 room-corner test with a door is representative of conditions that would develop inside of a railcar.


2021 ◽  
Vol 21 (2) ◽  
pp. 65-71
Author(s):  
Seunggoo Kang ◽  
Yi Chul Shin

In this study, to allow the flashover to occur, combustion tests were conducted by setting the conditions of a fire source using a large-scale compartment and changing the opening condition. As a result, the inside temperature of the compartment was measured under the fire source conditions. Moreover, according to the “Handbook on Design Calculation &#x0004d;ethods of Fire Behavior” by the Architectural Institute of Japan, the validity of the heat release rate required for the flashover to occur was verified through the correlation between <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>Q</mi><mrow><mi>F</mi><mi>O</mi></mrow></msub><mo>/</mo><msub><mi>Q</mi><mrow><mi>v</mi><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>A</mi><mi>T</mi></msub><msup><mrow><mo>(</mo><mi>k</mi><mi>p</mi><mi>c</mi><mo>)</mo></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup><mo>/</mo><msub><mi>c</mi><mrow><mi>P</mi></mrow></msub><mn>0</mn><mo>.</mo><mn>5</mn><mi>A</mi><msup><mi>H</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math>.


2019 ◽  
Vol 38 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Vytenis Babrauskas

Research literature comparing room-scale combustion toxicity performance of construction products is compared to bench-scale results. It is demonstrated that it is inappropriate the regulate construction products on the basis of performance in bench-scale toxicity tests, while it is economically unsound to suggest requiring room-scale testing for assessing combustion toxicity hazards. Instead, it is demonstrated that the combustion toxicity hazards of construction products are best addressed by regulating their heat release rate characteristics.


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