공연장 화재 축소모형의 전산시뮬레이션을 통한 방화막 영향 예측

김동환,이치영,김동균 한국화재소방학회 2018 한국화재소방학회논문지 Vol.32 No.3

Although a fire curtain plays an important role in preventing smoke from spreading to the auditorium in a theater fire,there has been insufficient research on fire curtains. In this study, to check the accuracy of numerical simulation, forprevious experiments using a reduced scale model, a numerical simulation was carried out, and the results were comparedwith previous experimental data. The fire curtain effect was then predicted numerically. A Fire Dynamics Simulator (FDS)was used, and the natural exhaust vent sizes were set to ∼10%, ∼5%, and ∼1% of the stage floor area. The smokemovement was visualized, and the mass flow rates and temperatures were measured and analyzed. In addition, the law ofsimilarity was used to examine the influence of a fire curtain in a real scale theater fire. Without the fire curtain, the presentnumerical simulation results were in agreement with the previous experimental data within reasonable accuracy. Meanwhile,the fire curtain affects the mass flow rates through the natural exhaust vent and proscenium opening, as well as the starttime of soot outflow to the auditorium. Overall, the present results can be used to develop a fire curtain system. 공연장 화재 시 방화막이 객석공간으로의 연기 확산을 억제하는데 중요한 역할을 할 수 있음에도 불구하고 이에대한 연구가 미흡한 실정이다. 본 연구에서는 전산시뮬레이션의 신뢰성을 확인하기 위하여 기존 축소모형실험에 대해 전산시뮬레이션을 수행하고 결과를 비교하였으며, 해당 전산시뮬레이션을 이용하여 방화막의 영향을 예측하였다. Fire Dynamics Simulator (FDS)를 이용하였고, 자연배출구 크기는 무대공간 바닥면적의 ∼10%, ∼5%, ∼1%로 설정하였다. 연기 거동을 가시화하고 질량 유량 및 온도 등을 측정하고 분석하였다. 실규모 공연장 화재에서의 방화막 영향을 예측하기 위하여 상사법칙을 활용하였다. 방화막이 없을 때 본 전산시뮬레이션 결과는 기존 축소모형실험 결과와비교적 잘 일치하였다. 한편, 실규모 공연장 화재 시, 방화막은 자연배출구 및 프로시니엄 개구부를 통한 질량 유량및 객석공간으로 soot 유출이 일어나는 시점에 지대한 영향을 미치는 것으로 나타났다. 본 연구 결과는 방화막 개발을 위한 기초 자료로 활용될 수 있을 것으로 판단된다.

공연장 화재 축소모형을 이용한 전산시뮬레이션 검토: 방화막 및 무대부 자연배출구 영향

양지현,백선아,이치영,김동균 한국화재소방학회 2019 한국화재소방학회논문지 Vol.33 No.5

In the present study, the influences of the fire curtain and natural vent in a theater fire were investigated through thenumerical simulation of a reduced-scale model of a theater fire using the Fire Dynamics Simulator (FDS). Based on aprevious experimental study using the reduced-scale model, the 1/14 reduced-scale model and its conditions wereconstructed according to the law of similarity with a real-scale theater. Through a series of numerical simulations, the smokemovements were visualized, and the temperatures in the stage and auditorium, mass flow rate of the outflow through naturalvent, and time at which smoke started moving toward the auditorium were measured and analyzed. The general trends onthe effects of the fire curtain and natural vent during the theater fire predicted by the present numerical simulation weresimilar to the previous experimental results. For quantitative comparison of the present numerical simulation and previousexperimental results, the mean percentage errors of temperatures in the stage and auditorium, and the mass flow rate ofoutflow through the natural vent were calculated. The present numerical simulation results showed good agreement withprevious experimental results with reasonable accuracy. 본 연구에서는 Fire Dynamics Simulator (FDS)를 이용한 공연장 화재 축소모형 전산시뮬레이션(Numerical simulation)을 통해 공연장 화재 시 방화막 설치 여부 및 무대부 자연배출구 개폐 영향을 검토하였다. 기존의 축소모형 실험연구를 바탕으로, 실존하는 공연장에 대해 상사법칙을 적용하여 1/14 비율로 축소하여 설정한 축소모형 및 조건을대상으로 하였다. 축소모형 전산시뮬레이션을 통해 연기 유동을 가시화하고, 무대부 및 객석부 온도, 자연배출구를통한 유출 질량 유량, 객석부로의 연기 유출 시작 시점을 측정하고 분석하였다. 전반적으로, 본 전산시뮬레이션에서예측된 방화막 설치 여부 및 무대부 자연배출구 개폐 영향에 대한 일반적인 경향은 기존 축소모형 실험에서와 유사한 것으로 나타났다. 본 전산시뮬레이션 결과와 기존 축소모형 실험 결과 간 정량적인 비교를 위해 무대부 및 객석부온도, 자연배출구를 통한 유출 질량 유량에 대해 평균 백분율 오차를 계산하였고, 본 전산시뮬레이션 결과와 기존축소모형 실험 결과가 비교적 일치함을 확인하였다.

Modifications to fire resistance ratings of steel frames based on structural configuration: A probabilistic-based approach

Behrouz Behnam 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.5

In this article, the role of spans number and length in fire-resistance ratings (FRRs) of fireproofed steel frames are investigated. First, over a span-lengthening scenario, two one- and three-bay frames under the ISO834 fire are examined. It is shown that the FRRs of the frames rely highly on the changes made on their span length. Second, a building designed for three spans number of three, four, and five under natural fire is investigated. The beams are designed for two load-capacity-ratios (LCRs) of optimum and ultimate. The fire curves are determined through a probabilistic-based approach. It is shown that the structural vulnerability vastly increases while the number of spans decreases. The results show that for an optimum LCR, while the five-span frame can meet the required FRR in 87% of the fire scenarios, the four- and three-span frames can meet the required FRR in only 56%, and 50% of the fire scenarios, respectively. For an ultimate LCR, the five-, four- and three-span frames can meet the required FRR in 81%, 50%, and 37.5% of the fire scenarios, respectively. Functional solutions are then proposed to resolve the insufficiencies in the results and to rectify the application of the standard-based FRRs in the cases studied. The study here highlights how employing current standard-based FRRs can endanger structural safety if they are not connected to structural characteristics; a crucial hint specifically for the structural engineering community who may be not well familiar with the fundamentals of performance-based approaches.

Trends of Post-fire Forest Recovery in the South Sikhote-Alin Mountains, Russian Far East

Komarova, Tatiana A.,Sibirina, L.A.,Papaik, M.J.,Park, J.H.,Kang, HoSang The Korea Society of Environmental Restoration Tec 2013 한국환경복원기술학회지 Vol.16 No.3

To understand natural regeneration and stand development after fire in mixed broadleaved-coniferous forests of Sikhote-Alin Mountains, ten sample plots of $50m{\times}50m$ size were established in 1975 and 1983 at the stands burned by wildfires in 1973 and 1982, respectively. And, the number of naturally regenerated seedlings were monitored in two $50m{\times}4m$ subplots in each plot. The most fire-sensitive conifer species is Abies nephrolepis, while Betula costata is the most fire-sensitive broadleaved tree species. The most fire-resistant species were Q. mongolica, T. taquetii and A. mono. The results of 20 and 30 years after the fire showed that pioneer tree species, e.g. Populus, Salix, and Betula, were regenerated immediately at the early stage of stand development and grew where there is a mono canopy layer with high density. On the other hand, the densities of successors, e.g. Pinus koraiensis, Picea jezoensis, Abies nephrolepis, Acer mono and Tilia taquetii, which were present in the study plots before the fire, increased gradually. Naturally regenerated tree species after forest fire by the growth rate were divided into three groups according to their annual height growth. The seral tree species (Betula costata, Betula platyphylla, Padus maackii, Populus tremula and Sarix caprea) belong to the first group and have the highest growth rate (from 40 to 96 cm per year). The late successional broad-leaved trees (Tilia taquetii, Acer mono and Quercus mongolica) belong to the second group and have intermediate annual height growth (from 3.7 to 13.5 cm per year). The late successional coniferous species (Picea jezoensis, Pinus koraiensis and Abies nephrolepis) form the third group and have the least annual height growth (from 1.4 to 3.5 cm per year).

Trends of Post-fire Forest Recovery in the South Sikhote-Alin Mountains, Russian Far East

( T A Komarova ),( L A Sibirina ),( M J Papaik ),( J H Park ),( H S Kang ) 한국환경복원기술학회(구 한국환경복원녹화기술학회) 2013 한국환경복원기술학회지 Vol.16 No.3

To understand natural regeneration and stand development after fire in mixed broadleavedconiferous forests of Sikhote-Alin Mountains, ten sample plots of 50m×50m size were established in 1975 and 1983 at the stands burned by wildfires in 1973 and 1982, respectively. And, the number of naturallyregenerated seedlingswere monitored in two 50m×4m subplots in each plot. The most fire-sensitive conifer species is Abies nephrolepis, while Betula costata is the most fire-sensitive broadleaved tree species. The most fire-resistant species were Q. mongolica, T. taquetii and A. mono. The results of 20 and 30 years after the fire showed that pioneer tree species, e.g. Populus, Salix, and Betula, were regenerated immediately at the early stage of stand development and grew where there is a mono canopy layer with high density. On the other hand, the densities of successors, e.g. Pinus koraiensis, Picea jezoensis, Abies nephrolepis, Acer mono and Tilia taquetii, which were present in the study plots before the fire, increased gradually. Naturally regenerated tree species after forest fire by the growth rate were divided into three groups according to their annual height growth. The seral tree species (Вetula costata, Вetula platyphylla, Padus maackii, Populus tremula and Sarix caprea) belong to the first group and have the highest growth rate (from 40 to 96 cm per year). The late successional broad-leaved trees (Tilia taquetii, Acer mono and Quercus mongolica) belong to the second group and have intermediate annual height growth (from 3.7 to 13.5 cm per year). The late successional coniferous species (Picea jezoensis, Pinus koraiensis and Abies nephrolepis) form the third group and have the least annual height growth (from 1.4 to 3.5 cm per year).

불의 애니메이션을 위한 복합적 기법

민경하(Min, Kyung-Ha) 한국게임학회 2007 한국게임학회 논문지 Vol.7 No.3

본 논문에서는 불을 애니메이션하고 가시화하는 새로운 방법을 제시한다. 불을 애니메이션하기 위해서 해결해야 하는 문제들 중에서 가장 어려운 문제는 불이 빛과 열을 주위로 방사하는 과정을 시뮬레이션하는 것이다. 이 방법을 해결하기 위해서 연료가 빛과 열을 발산하고 연소물이 되는 연소 과정을 유체 방정식이 구현되는 복셀화된 공간에서 시뮬레이션하는 복합적인 방법을 제안한다. 불의 움직임은 다른 유체의 경우와 같이 유체 방정식을 이용해서 시뮬레이션하며, 시뮬레이션의 각 단계마다 연소 과정에서 발생한 열이 유체의 온도를 높이고, 이렇게 높아진 온도가 불의 복잡한 움직임을 더욱 가중시키는 과정을 반복시키면서 불에 대한 애니메이션이 처리된다. 또한, 불과 불이 주변을 밝히는 효과를 처리하기 위해서 널리 알려진 포톤 매핑 알고리즘의 효율성을 개선한 새로운 가시화 알고리즘을 구현한다. In this paper, we present a new fire animation and visualization scheme. The most difficult problem in creating fire animation is how to simulate the mechanism of emitting lighting and heat of fire. We attack the difficulty by presenting a hybrid scheme that combines the simulation scheme and the combustion process in voxelized space where the numerical solution of the classical fluid equations is implemented. Therefore, the combustion process is simulated at each voxel and the amount of heat generated at the voxel is estimated. The generated heat will increase the temperature at the voxel, where results in the increase of turbulent motion of fire. We also propose a visualization scheme that modifies the photon mapping algorithm in order to render fire and various lighting effects of fire to the environments.

An experimental study of acoustically driven medium-scale pool fires

이기용,Andrew Lock,Anthony Hamins 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.8

A set of experiments has been conducted on a medium-scale propane fueled pool fire acoustically forced in order to facilitate repeatable measurements defining the flame’s transient behavior. The fuel flow was slightly perturbed at the pool fire’s natural frequency by a sine waveform driven with a loudspeaker which was installed under the burner. As a result of the perturbation, the puffing behavior of the pool fire and the fire shape were modified. As the magnitude of the sine wave was increased larger perturbations were clearly observed,based on the measurement of the radiative heat flux and image analysis. Temperature and soot volume fractions were measured along the center line and throughout a slice of the flame. The soot volume fractions in the flame region are in good agreement with the data of other researchers. The reproducibility of these measurements was established through several experiments. The acoustically driven flame provides the possibility of more repeatable measurements of the transient behavior of these pool fires.

An Experimental Study of Acoustically Driven Medium-Scale Pool Fires

이기용(Ki Yong Lee),Andrew Lock,Anthony Hamins 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40

Experimental investigations have been performed on a medium-scale pool fire acoustically forced in order to facilitate repeatable measurements defining the flame’s transient behavior. The fuel flow was slightly perturbed at the natural frequency of the pool fire by a sine waveform driven with a loudspeaker which was installed under the burner. As a result of the perturbation, the puffing behavior of pool fire and the fire shape were modified. As the magnitude of sine wave was increased more motion was clearly observed, based on the measurement of the radiative heat flux and image analysis. Temperature and soot volume fractions were measured along the center line and throughout a slice of the burner. The soot volume fractions in the flame region are in very good agreement with other researchers. The reproducibility of these measurements is established through several series of experiments. The acoustically driven flame provides the possibility of a more repeatable measurements of the transient behavior of these pool fires.

A Computational Model for Prestressed Concrete Hollow-Core Slab Under Natural Fire

R. Pe?enko,T. Hozjan,I. Planinc,S. Bratina 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.1

Performance-based approach, introducing a new two-phase computational model for determining the response of prestressed hollow-core concrete slab exposed to natural fire including heating and cooling phase, is presented. Firstly, the two-dimensional coupled hygro-thermo-chemical model is used to determine time dependent temperature and moisture field in the characteristic cross-section of the concrete hollow-core slab during fire. In addition, the influence of opening on the temperature distribution over prestressed hollow-core concrete slab is accounted for. Secondly, stress–strain state of prestressed concrete hollow-core slab is determined with a newly developed one-dimensional geometrical and material non-linear model, which includes a slip between concrete and tendon. Temperature dependent mechanical properties of concrete, tendon and bond stiffness are accounted for in the model. Model validation showed that the presented two-phase computational model is suitable for the analysis of prestressed hollow-core concrete slab exposed to natural fire. Furthermore, parametric studies revealed that heat exchange between the concrete section and the opening has a significant influence on the development of temperatures in the slab, particularly in the cooling phase, and consequently also on the development of slab displacements. In addition, it was identified that accounting for the slip between concrete and tendon enables the determination of the bond stress distribution and evaluation of the load bearing capacity of the contact.

An Ecocritical Reading of Jack London’s The Call of the Wild and “To Build a Fire”

Kim, Yeon-Man(김연만) 문학과환경학회 2016 문학과 환경 Vol.15 No.3

본 연구는 오늘날 인문사회학계의 중요한 화두가 된 생태비평(ecocriticism)적 시각을 미국 문학의 자연주의(naturalism) 전통에 투영해 보고자 하는 시도이었다. 생태적 관점과 자연주의적 관점 사이의 유사성과 대조점을 찾아보려는 시도는 자연에 대한 보다 깊은 성찰을 가능케 할 것이라는 가능성을 염두에 두었다. 이에 미국 주요 자연주의 작가 잭 런던(Jack London 1876 1916)을 표본으로 설정하고, 그의 대표작으로 손꼽히는 『야성의 부름』(The Call of the Wild 1903)과 단편 소설 「불을 지피다」 (“To Build a Fire” 1908)를 분석 대상 작품으로 연구를 진행하였다. 그 결과 두 작품에 속에서 생태비평적으로 유의미한 재해석의 가능성을 찾을 수 있었다. 다른 한편 생태비평과 자연주의 문학 사이에는 ‘자연’이라는 담론 대상의 연관성과는 대조적으로 자연관에 있어 많은 대조적인 면모 또한 존재한다는 것을 발견하였다. 즉, 자연이라는 큰 화두를 두고 생태비평과 자연주의 사이에 다소 좁혀지기 어려운 자연에 대한 시각과 견해가 존재한다는 점이 두드러진다. This paper explores the possible connections between naturalism and ecocriticism in the sense that the two literary positions seem to regard nature as the main target of study. The rationale behind this endeavor is to deepen our understanding of nature by exploring the links between naturalism and ecocriticism. Given that Jack London is one of the quintessential American naturalist writers, The Call of the Wild and “To Build a Fire” are chosen as sample texts that represent the naturalist tradition. This research, on the one hand, shows that there exist possibilities to rethink the naturalist works from an ecocritical perspective. On the other hand, it also shows that there lies a conceptual gap between the naturalist and ecocritical camps with regard to their notion of nature.