• 한국산업보건학회지
• /
• 제8권2호
• /
• pp.178-185
• /
• 1998

In order to evaluate and improve the performance of local exhaust ventilation systems for two TCE degreasing (A, B) and two electroplating (C, E) and one acid dipping & plating (D) operations located in Kimhae, the performance test was conducted with trace gases and a thermal anemometer (Kanomax 24-6111, Japan). For the inadequately designed systems, the improvement and redesigns in compliance with recommendation by ACGIH was suggested. The results of performance test for each system are as follows; 1. System of Workplace A was generally well-designed. Actual exhaust air flow rate was in excess of 68% above the recommended standard exhaust air flow rate. 2. System of Workplace B was very well-designed and completely enclosed. 3. All systems of Workplace C including hoods were poorly-designed and actual exhaust air flow rates were insufficient for open tanks. All systems should be upgraded according to ACGIH recommendations. 4. Supply and exhaust air flow rate of push-pull exhaust systems in Workplace D should be greatly increased. The width of flange of dipping tank hood should be increased with the value suggested. 5. System of Workplace E was well-designed. Actual exhaust air flow rate was in excess of 54% above the required.

• 한국화재소방학회논문지
• /
• 제23권3호
• /
• pp.79-84
• /
• 2009

도로터널의 환기 시스템은 차량 화재시 안전한 대피환경을 조성하는데 중요한 역할을 하며 종류환기방식과 횡류환기방식으로 대별된다. 본 연구에서는 횡류환기방식에서 대배기방식에 대한 터널내 풍속, 배연풍량, 개방되는 배기구의 위치에 따른 유동가시화 실험을 수행하여 연기의 이동특성을 고찰하였다. 그 결과 배연풍량을 연기발생량(Vc = 0)일 때 연기를 250m 이내로 제한할 수 있었으며, 터널 풍속이 1.75m/s와 2.5m/s일 때 배연풍량은 각각 $173m^3/s$, $236m^3/s$을 초과하여만 연기이동 거리가 250m로 제한할 수 있었으며 화재지점 가까이에 있는 2개의 배기구를 동시에 개방하는 경우가 배연이 더 잘 이루어졌다.

• 한국안전학회지
• /
• 제21권4호
• /
• pp.7-12
• /
• 2006

Recently, the application of transverse ventilation system with oversized exhaust ports has been increased in bidirectional road tunnel in order to improve smoke exhaust ability. Therefore, in this study, for decision of the optimal smoke exhaust rates in the transverse ventilation system, several standards of nations are compared and numerical simulations with variations of exhaust flow rates are carried out in terms of smoke spread distance by FDS ver. 3.1. As results, in the case of no internal longitudinal air velocity in tunnel, the smoke exhaust rate of $80m^{3}/s$ (the smoke generation rate at HRR of 20MW) is sufficient enough to limit the smoke spread within 250m in 6 minutes after the fire. However, in the case of the internal longitudinal air velocity at 2.5m/s, the smoke exhaust rate should be increased $130m^{3}/s$.

• 대한기계학회논문집B
• /
• 제29권4호
• /
• pp.469-476
• /
• 2005

Numerical modeling has been carried out to investigate the two-dimensional air flow in automobile interior with a forced exhaust close to main air inlet for typical ventilation modes. The characteristics such as streamlines and temperature fields in the passenger compartment room with the forced exhaust are analyzed with comparison of the cases without a forced exhaust. The simulation results show that air flow on the floor near the front seat is increased with the forced exhaust for all ventilation modes. Flow recirculation in the cabin is most active in mode 2 with a vertical suction inlet in comparison with other two modes. In particular, less time is taken for air temperature to reach the inlet temperature due to the forced exhaust for the ventilation modes. Finally, it could be predicted that ventilating air flow is much improved with the forced exhaust in the interior Modeling results in this study can be applied to the optimal design of automobile interior fur air ventilation system.

• 한국화재소방학회논문지
• /
• 제22권2호
• /
• pp.38-43
• /
• 2008

최근에 양방향 도로터널에서 배연효율의 증가가 요구됨에 따라 대배기에 의한 횡류식 양방향터널 배연시스템 적용이 증가되었다. 본 연구에서는 FDS Ver4.0을 사용한 수치해석을 통해 배연량과 화재강도를 변화시켜 최적배연조건을 도출하였다. 결과로, 터널 내부로 외부기류가 유입되는 경우에는 배연량을 증가시켜야 하는 것으로 나타났으며 화재지점으로 2.5m/s의 속도로 외기가 불어올 때 연기가 250m 이내로 제어되는 대배기구의 배연용량은 $244.8m^3/s$의 값으로 제어되어야 한다.

• 한국태양에너지학회 논문집
• /
• 제25권2호
• /
• pp.71-79
• /
• 2005

In this study, the ventilation performance of mechanical ventilation system in apartment House was analyzed through model test according to characteristics of air-vent. Then adequate interval of air-vent was suggested using computer simulation which will create comfort environment through improvement of ventilation performance in apartment house. The result of experiment with separation plate to prevent mixture of contaminated exhaust air with fresh supply air, the ventilation efficiency improved about 10%. The result of simulation with horizontal location of exterior air-vent, contaminated exhaust air is mixed regardless of interval variation. Consequently, mixture of the exhaust air can be prevented through locating the supply air vent on the top side and exhaust air vent on the lower side.

• 설비공학논문집
• /
• 제16권3호
• /
• pp.265-272
• /
• 2004

Based on the T-method, a new scheme for predicting air flow rate distribution in a bathroom exhaust system is developed. Introduction of individual duct route enables us to disintegrate a complicated multi-fan ductwork into a set of simultaneous single-fan subsystems. The scheme is validated via the analysis of a well-posed test problem, showing physical consistency. In order to demonstrate the utility and capability of our method, the bathroom ventilation system in a 20-story residential building is selected as an example. Under the typical design condition, the air flow rate of each exhaust fan at the balancing point is successfully predicted, and such information can lead to an engineering estimation for the overall system performance. While some deficiencies in ventilation are found at bathrooms at lower floors with 6mmAq-rated exhaust fans, they disappear over the whole building by using fans of enhanced static pressures, 7 and 8mmAq. Finally the present scheme seems to be useful for practical design of multi-branched, multi-fan ventilation systems.

• 산업기술연구
• /
• 제26권A호
• /
• pp.3-15
• /
• 2006

To determine the optimum ventilation systems during long tunnel excavation, the velocity vector profile and the contaminant's distribution at working place are studied using 2-D, 3-D numerical analysis. The main results can be summarized as follow; In case of long tunnels, blower-exhaust-mixture types which enable to use soft blast ducts is most appropriate in terms of ventilation and economical efficiency. Of the same ventilation types, ventilation efficiency has a difference according to blast ducts and the distance between fan and working place. The 3-D numerical result shows that arranging blower and exhaust ducts in the right and left corners of the tunnel respectively is effective to discharge contaminant. The result of the real measurement shows that CO concentration can be reduced to below 50 ppm, which is regulation value, as 16-minutes fan operation goes on.

• 한국안전학회지
• /
• 제19권3호
• /
• pp.1-8
• /
• 2004

This study aims to derive the operation method of a comprehensive ventilation system which is capable of providing passengers with safe exit paths from platforms in onboard fire situations. To accomplish this, the airflow distributions in subway platforms under 6 types of tunnel vent system were calculated in addition to having analyzed diffusion behaviors of smoke and heat exhaust in such states by performing 6 kinds of different ventilation scenarios in a 3-D Fire Dynamic Simulation (FDS) simulation model. In order to recommend the mechanical smoke exhaust operation mode, Subway Environmental Simulation(SES) is used to predict the airflow of the inlet and outlet tunnel for the subway station to clarify the safety evaluation fir the heat and smoke exhaust on subway fire events.

• 한국주거학회논문집
• /
• 제12권3호
• /
• pp.141-148
• /
• 2001

To design mechanical ventilation for bathroom of apartment houses where air supply and exhaust are taken into consideration, mock-ups of ventilation systems, widely used in bathroom of apartment houses with an area of 100$\textrm{m}^2$, were made and installed in a laboratory. These ventilation mock-ups were available for control of air supply and exhaust, and the sizes of supply openings were 40cm${\times}$1cm, 40cm${\times}$3cm, and 40cm${\times}$5cm. They were installed at five positions, spaced 45cm at a height of 5cm from the floor. The exhaust fan was designed for its operating voltage to be set to five steps(100V, 130V, 150V, 180V and 220V) in order to control its air flow rates. When the size and position of each supply opening were changed with the wind velocity of the exhaust fan set to the step 5, the ventilation rates were measured and analyzed by the concentration decay method of tracer gas method, in order to present an efficient mechanical ventilation system. The results of the study revealed that the ventilations rates would increase in the presence of supply openings, compared to the absence of supply openings, and that the larger the size of the supply opening, the more the ventilation rates. Therefore, it was found necessary to take air supply into consideration.