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

Abstract

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.

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

“…This aids in understanding and predicting the compartment fire phenomena and in designing buildings to reduce human and property damage.On the other hand, research on compartments with ceiling vents is applicable in atriums, theater, and ships [1]. Some studies on fire phenomena in compartments with ceiling vents have been reported [1][2][3][4][5]. Zhang et al[1] conducted a numerical simulation on the effects of ceiling vent location (center and corner) on smoke filling process, oxygen concentration, gas temperature, and vent flow characteristics (pressure, velocity, and mass flow rate) in a compartment fire with a natural ceiling vent.…”

“…On the other hand, research on compartments with ceiling vents is applicable in atriums, theater, and ships [1]. Some studies on fire phenomena in compartments with ceiling vents have been reported [1][2][3][4][5]. Zhang et al…”

“…and examined the temperature distribution in the compartment, vent flow pattern, velocity distribution, and mass flow rate. Park et al [3] investigated the scaling law for fire phenomena in a compartment with a single ceiling vent. Numerical simulations of a large compartment fire and a small compartment fire were conducted based on the scaling law.…”

Effects of Duct Height and Fire Location on Fire Phenomena of Enclosure with Two Horizontal Vents Installed on Ceiling

“…Furthermore, according to the horizontal vent area and fire location in case of a stage fire in a real-scale theater, the mass flow rate of horizontal vent flow was evaluated using the mass flow rate result of vent flow obtained from numerical simulation of the reduced-scale model and the scaling law. Park et al [10] investigated the scaling law for fire phenomena by performing numerical simulations for enclosure fires in which a horizontal vent existed. The accuracy of the scaling law for the mass flow rate and velocity distribution of the horizontal vent flow and the temperature distribution in the enclosure was checked based on the results of the reduced-scale model and full-scale numerical simulation.…”

“…They reported that the fire size had a significant effect on the average gas temperature rise when compared to the horizontal vent area. However, in these studies [3,[9][10][11][12], a single horizontal vent was used in a fire situation and the research under the condition of two horizontal vents is insufficient. When there are two horizontal vents, the vent flow behavior and fire phenomena can be affected by the condition of the two horizontal vents.…”