PISO 알고리즘을 이용한 세 가지 형태의 아트리움 공간에서 화재 발생시 연기 거동에 대한 수치해석적 연구

김성찬,유홍선,정진용 韓國火災 ·消防學會 1999 한국화재소방학회논문지 Vol.13 No.1

대형 건물에서의 화재시 연기 거동 및 거주자 피난에 관한 수치해석 연구

최상열,유홍선 중앙대학교 미래신기술연구소 2003 미래신기술연구소 논문집 Vol.12 No.1

본 수치해석 연구는 대형 건물에서의 화재 발생시 화재공간 내부의 온도장 및 연기거동을 해석하고, 거주자들의 피난을 모사하기 위해 FDS 코드와 SIMULEX 프로그램을 각각 사용하여 수행하였다. 서울의 대형 OO 빌딩의 지상 19 층과 지하 2 층을 해석 대상으로 하였으며, 초기 화재의 발생은 Fast 화재 성장모드로 가정하였고, 거주자의 다양성을 적용하여 피난을 해석하였다. 화재 발생 후, 지상 19 층의 경우 4 분여가 경과하면 국부적으로 천장 온도가 300 도 이상으로 상승하는 부분이 발생하게 되고, 사람의 키 높이 정도에서 가시거리가 5m 이하로 나타나게 되어 피난에 장애를 초래하는 것으로 나타났다. 지하 2 층의 경우는 아트리움의 영향에 의해 연기가 전체 공간으로 퍼져나가지 않았으며, 1.8m 정도의 높이까지 연층이 하강하는데 걸리는 시간은 약 5분 정도가 소요되었다. Smoke movement, temperature field, and evacuation of occupants in the nineteenth floor and the second floor underground of a large building on fire are studied. FDS code and SIMULEX program are used for the analysis of smoke movement, temperature field and evacuation of occupants, respectively. Fire growth mode is assumed as 'Fast' in the initial fires, and people characteristics are considered to account for the various evacuation feature. In case of fire on the nineteenth floor, after 4 minutes have passed, the region where the ceiling temperature is above 300℃ locally appears and visibility distance at the height of an adult becomes below 5m. This visibility distance causes the difficulty in people's evacuation. In case of a fire on the second floor underground, smoke did not spread over the whole area due to the geometry of atrium and it takes 5 minutes for the smoke layer move down to 1.8m vertical distance.

물분무노즐의 분사각이 화재실 내부의 온도장에 미치는 영향

김성찬,유홍선,박현태,방기영 한국안전학회 2003 한국안전학회지 Vol.18 No.2

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within 10℃. Numerical simulations of fire suppression are performed for 4 different injection angle(60°, 90°, 120° and 180°). The global mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhanced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

화재용 중저압 물분무 노즐의 분무특성의 관한 연구

김성찬,유홍선,박현태,방기영 한국산업안전학회 2003 한국안전학회지 Vol.18 No.1

The present study investigates the spray characteristics of water mist nozzle with mid-low pressure for fire suppression. The examined nozzle types are swirl nozzle. The result shows that K factor of water mist nozzle is much smaller than those of general sprinkler. Spray angle of spiral nozzle is largest and more than 150˚. SND(Sauter Mean Diameter) of water mist nozzles is ranged between 100 and 200㎛ through measuring by image processing method. The spray pattern of spiral nozzle represent that water flux of first stream is 2 times larger than that of second stream. This study will contribute better understandings of the water-mist spray characteristics and useful data for developing the water-mist nozzles.

아트리움 공간에서의 화재성상에 관한 축소모델 실험연구

김충익,유홍선,류승관 (社團法人) 韓國火災 ·消防學會 1999 한국화재소방학회논문지 Vol.13 No.4

터널 화재시 자연 배기에 의한 연기 거동에 관한 실험적 연구

이성룡,김충익,유홍선 한국화재소방학회 2001 한국화재소방학회논문지 Vol.15 No.1

본 연구는 터널내 화재발생시 자연 배기에 의한 연기의 거동을 해석하기 위하여 축소모형 실험을 수행하였다. 터널내 연기의 유동은 부력에 의해 지배되므로 Froude scaling에 의해 실물 터널을 1/20로 축소한 모형터털에서 실험을 수행하였으며 배기구의 위치변화에 따른 영향을 평가하기 위하여 화원으로부터 각가 1 m, 2 m, 3 m 떨어진 곳에 배기구를 대칭으로 위치시켜 세 가지 경우에 대해 실험을 실시하였다. 지름이 4.36cm인 화원의 경우, 배기구의 위치에 관계없이 배기구 통과 후 연층의 온도가 배기를 실시하지 않는 경우와 비교하여 약 7~8℃ 낮게 유지되었다. 지름이 5.23cm인 화원의 경우, 배기구가 화원에 가까울수록 배기구 통과 후 연기의 평균속도가 감소하였으며 최대 3.86초가 지연되었다.CASE 1에서는 배기구 통과 후 천장에서 약 8℃ , 수직온도가 약 7℃ 감소하였으며, CASE 2에서는 천장과 수직온도가 약 3℃ 감소하였으며, CASE 3에서는 각각 약 2℃가 감소하였다. 레이저와 디지털 캠코더를 이용하여 배기구 주위의 연기 유동을 가시화하여 화재발생 약 1분 후부터 연층이 두께가 터널높이의 25%이하로 일정하게 유지되는 것을 확인할 수 있었다. In this study, reduced-scale experiments were conducted to understand smoke movements in tunnel fires with the natural ventilation. The 1/20 scale experiments were conducted under the Froude scaling since the smoke movement in tunnels is governed by buoyancy force. Three cases of experiment, in which a natural vent location varied from 1 m,2 m,3 m from the fire source symmetrically, were conducted in order to evaluate the effect of the position of ventilation systems on smoke movement. In case of a pool whose diameter is 4.36 cm, the temperature of smoke layer passed through the vent was maintained 7~8℃ less than of smoke layer without a vent. In case of s pool whose diameter is 5.23 cm, the average velocity passed through the vent was decreased when it was close to the fire source. And the maximum delay time was 3.86s. In CASE1, the ceiling temperature was decreased by approximately 8℃ and the vertical temperature was decreased by approximately 7℃. In CASE 2, both ceiling and vertical temperature were decreased by 3℃ and in CASE 3, they were decreased by 2℃ each. It was confirmed that the thickness of smoke layer was maintained uniformly under the 25% height of through the visualized smoke flow by a laser sheet and the digital camcoder.

경사 터널내 화재시 임계속도에 관한 실험적 연구

이성룡,김충익,유홍선,김혁순,전명배 한국화재소방학회 2004 한국화재소방학회논문지 Vol.18 No.1

본 연구에서는 터널 화재시 임계속도에 대한 터널 경사의 영향을 파악하기 위하여 축소모형 실험을 실시하였다. Froude 상사를 사용하여 1/20로 축소된 모형터널에서 실험을 실시하였으며, 가연물질로는 에탄올 사용하였다. 정사각형 풀을 사용하였으며 발열량은 2.47~12.30 kW이다. 임계속도가 발열량의 1/4승에 비례하여 증가하였다. 터널 경사가 증가할수록 굴뚝효과로 인해 연기의 유동속도가 증가하여 임계속도가 증가하였다. In this study, reduced-scale experiments were conducted to analyze an effect of tunnel slope on critical velocity. The 1/20 scale experiments were carried out under the Froude scaling using ethanol pool fire. Square pools ranging from 2.47 to 12.30 kW were used experiments. Critical velocity varied with one-fourth power of the heat release rate. As the slope of the tunnel increases the critical velocity comes to be fast due to the increase of the chimney effect.

The Effects of Water Mist on the Compartment Fire

Ryou, Hong-Sun,Kim, Sung-Chan The Society of Air-Conditioning and Refrigerating 2004 International Journal Of Air-Conditioning and Refr Vol.12 No.1

The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water spray. The predicted temperature fields of smoke layer are compared with those of measured data. Numerical results agree with the experimental results within $10^{\circ}C$ in the case without water mist. In the case of fire suppression with water mist, numerical results do not predict well for temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with those of measured data. The reason for the discrepancy between predicted and measured data is due to the poor combustion modeling during the injection of water mist. More elaborate models for numerical simulation are required for better predictions of the fire suppression characteristics using water mist.

An Experimental and Numerical Study on Thermal Performance of a Regenerator System with Ceramic Honeycomb

Ryou, Hong-Sun,Noh, Dong-Soon,Hong, Sung-Kook,Lee, Seong-Hyuk The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.3

The aim of this paper is to perform the experiment and the numerical simulation for investigating the heat transfer in a regenerator system with ceramic honeycomb and to suggest a useful correlation for optimization of the regenerator system. For achieving this, the effects of some parameters were investigated, e. g., switching time, cell size and length of honeycomb on the mean temperature efficiency. The measured temperatures by R-type thermocouples were compared with the predictions by means of the commercial package, STAR-CD. A useful correlation for thermal efficiency was newly proposed as a function of the normalized switching time, defined in terms of switching time, cell size and length of honeycomb. The results showed that the thermal efficiency is above 90% and the normalized heat exchange rate is higher than 80% when the normalized switching time is less than 1000.

Development and Application of a New Spray Impingement Model Considering Film Formation in a Diesel Engine

Ryou, Hong-Sun,Lee, Seong-Hyuk,Ko, Gwon-Hyun,Hong, Ki-Bae The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7

The present article presents an extension to the computational model for spray/wall interaction and liquid film processes that has been dealt with in the earlier studies (Lee and Ryou, 2000a). The extensions incorporate film spread due to impingement forces and dynamic motion induced by film inertia to predict the dynamic characteristics of wall films effectively. The film model includes the impingement pressure of droplets, tangential momentum transfer due to the impinging droplets on the film surface and the gas shear force at the film surface. Validation of the spray/wall interaction model and the film model was carried out for non-evaporative diesel sprays against several sources of experimental data. The computational model for spray/wall interactions was in good agreement with experimental data for both spray radius and height. The film model in the present work was better than the previous static film model, indicating that the dynamic effects of film motion should be considered for wall films. On the overall the present film model was acceptable for predication of the film radius and thickness.