• 한국화재소방학회논문지
• /
• 제31권2호
• /
• pp.37-43
• /
• 2017

이 연구에서는 4종의 삼나무, 스프러스, 나왕, 레드파인 시험편을 콘칼로리미터(Cone calorimeter, ISO 5660-1, 2)와 연기밀도시험기(ASTM E 662)를 이용하여 연소성을 시험하였다. 그 결과, 삼나무가 착화시간이 가장 빨랐고 평균열방출율($HRR_{mean}$)이 $58.52kW/m^2$으로 가장 낮게 나타났다. 그리고 레드파인의 평균열방출율($HRR_{mean}$)이 $71.75kW/m^2$으로 가장 높게 나타났다. CO 발생량에서는 나왕과 삼나무가 가장 많이 발생하였고, 반대로 $CO_2$ 발생량에서는 레드파인과 스프러스가 가장 많이 발생하였다. 동적방법에서의 총연기방출율은 레드파인이 연기가 가장 많이 발생하였고, 스프러스가 가장 적게 발생하였다. 정적방법에서의 연기밀도는 레드파인이 훈소(Non-flaming) 방식과 불꽃(Flaming) 방식에서 가장 높았다. 나왕은 훈소(Non-flaming) 방식에서 2번째로 연기가 많이 발생한 데 반하여 불꽃(Flaming) 방식에서는 가장 적게 발생한 것을 알 수 있었다. 열방출율 측면에서 화재위험성은 4가지 시험편 중 레드파인이 가장 높았다. 연기발생 관점으로 보아도 동적인 방식과 정적인 방식 모두 레드파인이 화재 위험성이 가장 높은 재료였다.

• 한국안전학회지
• /
• 제19권3호
• /
• pp.45-50
• /
• 2004

4-panel of 1m height and 45cm width were fixed on the $40cm{\times}40cm$ bottom plate and the opening of the panel comer was 5cm. Diameter of stainless vessel is loom and its height is 2cm and it located at the center of the bottom plate. 78mL liquid fuel was filled in the vessel and its depth was 1cm. Flame temperature was measured with K type thermocouple, and radiation heat of flame was measured with heat flux meter. Flame height and its behavior was visualized with video camera. and mass burning rate was measured by fuel combustion time. According to the development of fire, flame swirling was begin. From the experiment the mass burning rate was larger and the height of flame was higher than the usual pool fire flame. Flame temperature and heat flux also increased far more than the pool fire. Consequently the swirling air flow through the openings between the panel and thermal buoyance contribute to increase of heat release rate, flame length and mass burning rate.

• 한국화재소방학회논문지
• /
• 제24권5호
• /
• pp.60-67
• /
• 2010

화재분석모델이 제한사항 내에서 화재 피해를 신뢰성 있게 예측하기 위해서는 화재분석모델에 대한 검증분석이 반드시 이루어져야 하며, 이러한 검증분석 과정은 일반적으로 실증실험 결과와 비교함으로서 이루어진다. 본 연구의 목적은 화재분석모델인 FDS의 이중격실 Pool 화재에 대한 예측 능력을 평가하고, FDS의 중요 입력값(열방출률 및 환기량)의 미소변화에 따른 출력값(온도, 농도, 열유속)의 민감도를 분석하기 위함이다. FDS의 예측능력 평가와 FDS 입력변수의 민감도 분석을 위해 국제공동연구 PRISME 프로잭트로부터 화재실증 결과와 FDS 결과물을 비교분석하였다. 이중격실 Pool 화재에 대한 FDS의 예측능력은 화재실증 실험결과와 비교하여 약 ${\pm}$20% 오차범위를 나타내었다. 또한, FDS의 입력변수에 대한 민감도는 열방출율의 미소변화에 따라 비교적 높은 출력값의 변화가 나타났으며, 환기량의 미소변화에 따라 출력값 변화는 연소생성물의 농도에만 영향을 미쳤다.

• 한국태양에너지학회 논문집
• /
• 제26권1호
• /
• pp.21-28
• /
• 2006

Changes in building construction methods and repairing of older buildings have reduced infiltration rate. Synthetic materials, release airborne particles and uneven healthy odor are increased. For preventing pollutants introduce fresh outdoor air into the building, simply letting fresh outdoor air into building, however, Is not a cost-effective way to ventilation. When additional ventilation is added to an existing HVAC system, the heating and cooling equipment, often cannot handle the increased load. A HRV provides a way to minimize in energy costs while introducing fresh air to a building. In this study, the economical research of HRV, made of three types of materials, are conducted. Heat recovering characteristics are studied at seasonal outdoor air conditions based on the outdoor air property condition at, Seoul in 2002. As a results, the average sensible effectiveness is 0.75 in the sensible heat exchanger and average total effectiveness is 0.65 in the total heat exchanger. The pay back period of the sensible heat exchangers are $3.2{\sim}3.5$ year and it of total heat exchanger is 2.2 years.

• 한국철도학회논문집
• /
• 제7권3호
• /
• pp.180-185
• /
• 2004

The present study investigates the effect of fire growth model on fire development characteristics in a carriage. The parallel processing version of FDS code is used to simulate the fire driven flow in a carriage and two types of fire growth model which are flame spread model and t$^2$ model are examined for the same geometrical condition. The heat release rates(HRR) of both model are similar each other until 30 s after ignition, but the flame spread model predicts 5 times higher than those of the t$^2$ fire model during the quasi-steady fire period. Maximum heat release rate in the case of flame spread model reaches about to 12 MW at 100 s after fire ignition. Also, various database of fire properties for combustible materials and more elaborate combustion model considering the flame spreading phenomena are required for better predictions of fire development characteristics using numerical simulation.

• 한국자동차공학회논문집
• /
• 제9권4호
• /
• pp.10-17
• /
• 2001

The performance of a radiator is generally determined using a wind tunnel, in which the air velocity is uniform. However, when it is installed in a car, the distribution of the air velocity becomes nonuniform due to front-end openings, cross members, and horns etc., resulting in lower performance. In this study, several underhood flow simulations have been first performed to get flow rates and velocity distributions over the radiator. Secondly heat release rates are calculated by both a performance curve and a radiator model. Finally, using an engine cooling system simulator, radiator-top-tank temperature is predicted and the variations of heat release rate and radiator-top-tank temperature with nonuniformity of air velocity distributions are analyzed. The results show that the current engine cooling model successfully accounts for the nonuniformity effects that should be considered for higher accuracy in predicting engine cooling performance.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.1426-1431
• /
• 2011

A study on the standardization of design fire HRR(heat release rate) curve was conducted for various railcar from the fire simulation or the fire tests. These standard curves are listed on the tunnel fire safety manual which will be used for the QRA(quantitative risk analysis) process of the long railway tunnels. The design fire curve is based with four simple factor representing the key of fire curve characteristics. Flashover time, maximum HRR and burn out time are the key factors of the design fire curve. Specially total heat release is decided by the burnable material amount in the car.

• Journal of Advanced Marine Engineering and Technology
• /
• 제24권4호
• /
• pp.421-426
• /
• 2000

A study on the combustion and exhaust emissions characteristics of diesel engine with various suction air humidity is performed experimentally. In this paper, suction air humidity is changed from RH 50% to RH 90%, the experiments are performed at engine speed 1800rpm, and main measured parameters are cylinder pressure, fuel consumption rate, CO, HC, NOx and Soot emissions etc. Increase of suction air humidity from RH 50% to RH 90% does not effect specific fuel consumption, decreases maximum pressure in cylinder, ratio of maximum pressure rise and net heat release, and delays ignition timing. Also, that increases CO and HC emissions, decreases NOx emissions, but does not constant in changing tendency on emission.

• 대한기계학회논문집B
• /
• 제20권2호
• /
• pp.605-615
• /
• 1996

Laminar flows in which mixing and chemical reactions take place between parallel streams of reactive species are studied numerically. The governing equations for laminar flows are from two-dimensional compressible boundary-layer equations. The chemistry is a finite rate single step irreversible reaction with Arrhenius kinetics. Ignition, premixed flame, and diffusion flame regimes are found to exist in the laminar reacting mixing layer at high activation energy. At high Mach numbers, ignition occurs earlier due to the higher temperatures in the unburnt gas. In diffusion regimes, property variations affect the laminar profiles considerably and need to be included when there are large temperature differences. The maximum temperature of a laminar reacting mixing layer is almost linear with the adiabatic flame temperature at low heat release, but only weakly at high heat release.

• 한국화재소방학회논문지
• /
• 제32권2호
• /
• pp.17-23
• /
• 2018

본 연구에서는 Buckingham 파이 정리를 이용하여 구획 공간에서 화재가 발생한 경우 벽면을 구성하는 재료의 열전도 계수와 내부 온도의 상관관계에 관한 연구를 수행하였다. 이를 위해서 기존 무차원 변수의 주요 인자를 고려하여 발열량, 열전도계수, 구획공간의 체적, 벽면 두께 그리고 대류 열전달 계수의 관계를 분석하였다. 또한, 발열량에 대한 화염에서의 최대 온도 그리고 벽면의 온도를 산출하기 위해서 내화보드를 사용하여 ISO 9705 룸 코너 시험기(Room Corner Tester)의 1/6 크기를 갖는 축소 규모의 구조물을 제작하였으며, 10 cm, 15 cm 그리고 20 cm인 정사각형 화원에 대해서 가솔린 화재실험을 수행하여 국부 지점의 산소 농도와 화염에서의 온도분포를 측정하였다. 그 결과 대류 열전달 계수와 열전도 계수의 변화에 따라서 외벽에서의 온도가 증가하는 조건을 제시하였으며, 발열량 변화에 대한 Buckingham 파이의 무차원 경험식을 도출하였다. 본 연구 결과는 구획 공간에서 외벽 형상 및 열전도 계수의 변화를 고려한 화재 현상을 연구하기 위한 기초 자료의 활용이 가능할 것으로 사료된다.