Assessment of Fire Model Uncertainty of Fire Dynamics Simulator in Multiple Compartments of Nuclear Power Plant

Han, Haoxue; Hwang, Cheol-Hong; Lee, Sang Kyu; Lee, Jai Ho

doi:10.7731/kifse.a08e2c08

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…In this study, the scaling law is investigated for fire phenomena in a compartment with a horizontal natural opening installed using the fire dynamics simulator (FDS). The FDS is a widely used program in the field of fire and firefighting, and its accuracy in predicting fire phenomena has been examined in an earlier study [15]. In this study, a large-scale compartment is constructed based on a scaled model of a theater stage reported in the previous studies [9,10]; then, a numerical simulation is performed.…”

Section: Parametermentioning

confidence: 99%

Examination of the Scaling Law of Fire Phenomena in Compartment with Horizontal Natural Opening using Numerical Simulation

2022

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The scaling law was examined using numerical simulation for fire phenomena in a compartment with a horizontal natural opening in this study. The results of the large-scale conversion of the scaled model numerical simulation results ([Small-scale] condition) from the earlier studies obtained by applying the scaling law were compared to those of the large-scale numerical simulation performed in this study ([Large-scale] condition). The overall trends for the effects of horizontal natural opening area and fire source location on the discharge mass flow rate through the horizontal natural opening, temperature distribution in the compartment, and flow velocity through the horizontal opening were found to be identical under the [Small-scale] and [Large-scale] conditions. A complex bidirectional flow was observed through the horizontal natural opening under the conditions of this study and the accuracy in predicting the average W-velocity value based on the scaling law was low; however, the accuracy in predicting the range of velocity fluctuation was higher than the average value under certain conditions. Based on the standard deviation of the numerical simulation results, the percentages of the data within ± 30% of the difference between the [Small-scale] and [Large-scale] conditions relative to the total number of data were 100, 75, and 88% for the discharge mass flow rate, temperature, and flow velocity through the horizontal natural opening, respectively. The accuracy of the scaling law was found to be high for the discharge mass flow rate under the conditions considered in this study.

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Section: Parametermentioning

confidence: 99%

Examination of the Scaling Law of Fire Phenomena in Compartment with Horizontal Natural Opening using Numerical Simulation

2022

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“…Table 1 shows the exemplified bias factors and relative standard deviations for temperatures and velocities reported in a reference [8]. Meanwhile, Han et al [9] evaluated the uncertainty of FDS based on the results of PRISME3 [10] fire experiment conducted by the Institute for Radiological Protection and Nuclear Safety (IRSN). Based on the experimental and numerical simulation results, they obtained the bias factor and relative standard deviation using Eqs.…”

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confidence: 99%

Comparative Study of Numerical Simulation and Experiment on Temperature Distribution and Central Vent Flow Velocity in Ceiling-vented Compartment Fire

Park,

Kim,

Lee

2023

Int J Fire Sci Eng

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In this study, we conducted numerical simulations to analyze fire phenomena in a compartment with a ceiling vent and compared these numerical simulation results with previous experimental data. Based on the previous experimental conditions, under the heat release rate of 1.5 kW, the vent areas of 1% and 10% of the floor area and the fire sources both at the center and side of the floor were tested. Overall trends of temperature distribution and central vent flow velocity in the present numerical simulations were consistent with those in the previous experiments. The temperature within the compartment was observed to be higher when the vent area was smaller. For compartment with a smaller vent area, the temperature distribution showed minor variations with the fire source location. However, with a larger vent area, temperatures were notably higher when the fire source was at the side than at the center. The present numerical simulations slightly overestimated the temperatures from the previous experimental results, resulting in a bias factor of 1.07 and a model's relative standard deviation of 0.07 for temperature. Regarding the flow velocity at the center of ceiling vent, the fluctuations over time were more pronounced when the fire source was centrally located. When the fire source was at the center, the average central vent outflow velocity was higher for compartment with a larger vent area. When the fire source was positioned to the side, the vent area appeared to have minimal impact on the average central vent outflow velocity. It was also observed that the average central vent outflow velocity was higher when the fire source was centrally placed when compared to a side location. The present numerical simulations underestimated the previous experimental results for the average central vent outflow velocity, and the bias factor and the model’s relative standard deviation for the average central vent outflow velocity were 0.63 and 0.39, respectively.

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“…

Fire modeling-based research has recently been conducted to quantitatively evaluate the fire-induced damage and the safety of structures and system equipment to ensure the fire safety of nuclear power plants (NPPs) in South Korea as well as worldwide [1]. Depending on the prediction accuracy and uncertainty of the fire model, the prediction results of fire modeling are required to go through comparison and validation stages based on measurement results from various fire experiments [2].

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confidence: 99%

Application of FDS to Predicting Fire Spread in a Horizontal Cable Tray

et al. 2022

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With regard to cable tray fires, comparing the prediction results obtained through fire simulations with the measurement results from fire experiments conducted under real-life conditions is essential to ensure the predictive reliability of the model. In determining the validity of the calculation process and procedure performed in a specific fire experiment, the result may vary depending on the user’s capability. This is because of the high user dependence due to the characteristics of the fire model. In this study, we examined whether the actual spread of fire could be similarly predicted when the physical quantities of cable tray fires suggested by previous studies were applied. We also applied a fire modeling method considering the arrangement of cables to predict appropriate fire spread in a nuclear power plant and then performed a comparative analysis of the results and the experimental results. The prediction results, in terms of the fire spread time, varied depending on the arrangement type (whether loosely and tightly arranged) of cables. Finally, we devised a process of accurately predicting the heat release rate (HRR) curve as compared to the experimental results by using a sensitivity analysis of the input parameters (density, specific heat, and thermal conductivity) corresponding to the physical properties considered in the fire model.

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Assessment of Fire Model Uncertainty of Fire Dynamics Simulator in Multiple Compartments of Nuclear Power Plant

Cited by 3 publications

References 6 publications

Examination of the Scaling Law of Fire Phenomena in Compartment with Horizontal Natural Opening using Numerical Simulation

Examination of the Scaling Law of Fire Phenomena in Compartment with Horizontal Natural Opening using Numerical Simulation

Comparative Study of Numerical Simulation and Experiment on Temperature Distribution and Central Vent Flow Velocity in Ceiling-vented Compartment Fire

Application of FDS to Predicting Fire Spread in a Horizontal Cable Tray

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