단일 수평 개구부 및 화원 조건이 구획실 화재 현상에 미치는 영향에 대한 실험 및 전산해석 연구

Abstract

In this study, the effects of single horizontal opening and fire source conditions (i.e., horizontal opening area, heat release rate, and fire source location) on fire phenomena in enclosure were experimentally and numerically investigated. Through a series of experiments, the temperature distribution in enclosure and the velocity through the horizontal opening were measured. In addition, the flows through the horizontal opening were visualized and their mass flow rates were estimated. Then, the numerical simulation using fire dynamics simulator (FDS) was performed considering the experimental conditions. Through comparing the numerical simulation results with the experimental ones, the accuracy of the numerical simulation using FDS was examined. The temperatures in the enclosure decreased with increasing the horizontal opening area and decreasing the heat release rate. Under the smaller horizontal opening area condition, the effect of fire source location on the temperature in the enclosure seemed to be insignificant. However, under the larger horizontal opening area condition, the case of center located fire source showed lower temperatures in the enclosure than that of side located fire source. Under the center located fire source condition, when the horizontal opening area increased from 1% to 5% of the floor area, both of average velocity and average outflow velocity through the horizontal opening increased. However, when the horizontal opening area increased from 5% to 10% of the floor area, the variation in velocity seemed to be minor. In addition, the case of center located fire source showed higher average velocity and average outflow velocity than that of side located fire source. Through the visualization of flows through the horizontal opening, it was found that the bidirectional flow patterns were observed under all conditions. Based on the flow visualization results, the correlation to predict the smoke outflow area was proposed. Using the measurement results of average outflow velocity and smoke outflow area, the mass flow rate was estimated. Under the same fire source location condition, larger horizontal opening area and heat release rate resulted in increasing the estimated mass flow rate. Additionally, under the same horizontal opening area condition, the case of center located fire source exhibited larger estimated mass flow rate than that of side located fire source. Through comparing the results between experiment and numerical simulation, it was confirmed that the general trends of temperature, and flow velocity and mass flow rate through horizontal opening were similar, and their quantitative differences were presented and discussed in detail.