• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2010.10a
• /
• pp.123-126
• /
• 2010

터널내에 설치되는 제트팬은 비상시에는 연기와 같은 유독가스를 제거하는데 사용되며 평상시에는 장대터널에 있어서 차량에 의해 발생한 오염공기를 제거하는 중요한 역할을 한다. 파량의 피스톤효과에 의해서 일부 제거되기는 하나 1km이상의 장대터널에서는 반드시 필요로 한다. 이러한 제트팬의 효율적인 환기 및 제연설계를 위하여 CFD해석과 더불어 모형실험을 실시함으로서 터널내에 소실되는 에너지를 정량화하고 그 원인 파악과 함께 효율적인 환기설계를 위한 연구이다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.20 no.2
• /
• pp.305-315
• /
• 2018

In this study, the ventilation characteristics and the relationships between the required ventilation flow rate and the ventilation system flow rate was investigated by numerical method for the optimum design of the transverse ventilation and semi-transverse ventilation system in road tunnels. The following results were obtained. In supply exhaust transverse ventilation system, the system supply-exhaust air flow rate is theoretically equal to the difference between the required ventilation flow rate and natural ventilation flow rate. However, it is shown that it increases by about 10% in the analysis results. And, in the case of the longitudinal air flow rate is increased by installed jet fans, ventilation system air flow rate is reduced. However, as the longitudinal air flow rate increases, the concentration of pollutants in the tunnel decreases, so the exhaust effect of pollutants decreases, and the effect of reducing the system air flow rate is decreased. In case of semi-transverse with only air supply, ventilation system air flow rate is equal to required ventilation air flow rate when tunnel inlet velocity is negative, but results is shown it is increased within about 13.3%. Also, it was found that ventilation effect can not be expected even if the jet fans are increased when the tunnel inlet velocity is negative.

• Journal of Yeungnam Medical Science
• /
• v.10 no.1
• /
• pp.1-17
• /
• 1993

고빈도 환기법은 최근에 개발되어 임상에 응용되면서 호흡생리학, 마취학, 집중치료의 학등의 분야에서 호흡부전의 새로운 치료법으로 관심이 집중되고 있는 환기법이다. 현재까지 고빈도 환기법중 고빈도 양압 환기와 제트 환기는 비교적 많은 연구가 되고 있고 임상적으로 사용되고 있으나 고빈도 진동 환기법은 제한적으로 사용되고 있다. 앞으로 고빈도 진동 환기법에 대해서도 더 많은 연구가 되어야 할 것이다. 또한 최근 개발되고 있는 고빈도 흉벽 진동 환기와 체표면 진동 환기에도 관심을 기울이면 호흡부전 환자의 치료에 바람직한 새로운 환기법이 될 수 있을 것으로 기대된다. 현재 고빈도 환기법의 몇몇 적용형태는 기관지-늑막루등의 폐압손상으로 인한 병변의 치료외에도 기관수술, 흉부수술, 뇌수술에서 수술부위의 움직임을 최소화시키면서 충분한 가스교환율 이룩할 수 있어서 효과적으로 이용되고 있다. 그러나 응급심폐소생술, 폐쇄성 폐질환, 성인 또는 영아 호흡곤란증후군등과 같은 질환에서의 적용은 더 규명되어져야겠다. 고빈도 환기법의 여러가지 문제점중 적절한 환기빈도의 결정, 충분한 습도를 공급하는 장치, 고빈도 환기의 정확한 감시장치의 개발등은 앞으로 우선적으로 해결해야 할 문제점이다. 또한 임상에 더욱 효과적으로 응용될 수 있는 새로운 환기법이 되기 위해서는 고빈도 환기법의 호흡생리와 안정성등에 관한 연구도 병행되어야겠다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.8 no.4
• /
• pp.335-344
• /
• 2006

The domestic standards which used the standards of Road Association of Japan standards presents the distances of between jet-fans by the caliber of jet-fan. However, the Permanent International Association of Road Congress (PIARC) encourages it to be ten times a diameter of the tunnel. The distance of jet-fans installed in bases of two standards differs as much as two times, as so the proper basis after analysis of internal air current is needed since such difference can lead to disadvantage for selection of ventilation configuration. Based on Froude modeling theory, 1/40 scale acrylic model of a tunnel (215mm in diameter and 6.9m in length) and jet-fan (26.3mm and 31.6mm in caliber) was made for the measurement of changes in pressure and velocity due to the extension of tunnel for analysis of internal air current. And we measured the changes in pressure of surroundings of a jet-fan for confirmation of recirculation due to the exterior airs when the jet-fan is on. The results of the model test show that internal air current was not influenced by the caliber of jet-fan and its changes in pressure and velocity were stable in the point where it was nine times of diameter of the tunnel. Also the recirculation when the jet-fan is on could be verified. According to such results, in the cases of installing jet-fan in tunnels, the distances between jet-fans needs to be more than nine times the diameter.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.3
• /
• pp.301-310
• /
• 2013

Jet fans are installed in road tunnels in order to maintain critical velocity when fire occurs. Generally the number of jet fans against fire are calculated by considering critical velocity and flow resistance by wall friction, vehicle drag force, thermal buoyance force and natural wind. In domestic case, thermal buoyance force is not considered in estimating the number of jet fans. So, in this study, we investigated the pressure loss due to the thermal buoyance force induced by tunnel air temperature rise and the impact of thermal buoyance force on the number of jet fans by the numerical fire simulation for the tunnel length(500, 750, 1000, 1500, 2000, 3500m) and grade (-1.0, -1.5, -2.0%). Considering the thermal buoyance force, number of jet fans have to be increased. Especially in the case of 100MW of heat release rate, the pressure loss due to thermal buoyance force exceed the maximum pressure loss due to vehicle drag resistance, so it is analyzed that number of 2~11 jet fans are needed additionally than current design criteria. Thus, in case of estimating the number of jet fans, it must be considered of thermal buoyance force induced tunnel air temperature rise by fire.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2010.04a
• /
• pp.21-25
• /
• 2010

터널내에 설치되는 제트팬은 비상시에는 연기와 같은 유독가스를 제거하는데 사용되며 평상시에는 장대터널에 있어서 차량에 의해 발생한 오염공기를 제거하는 중요한 역할을 한다. 파량의 피스톤효과에 의해서 일부 제거되기는 하나 1km이상의 장대터널에서는 반드시 필요로 한다. 제트팬의 가장 많은 에너지 손실이 벽면에서 이루어지고 있으며 이를 통하여 터널내에 소실되는 에너지를 정량화하고 그원인 파악과 함께 효율적인 환기설계를 위한 연구이다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.6 no.2
• /
• pp.103-109
• /
• 1994

An experimental study is performed on the flow characteristics of a swirl-jet diffuser for factory ventilation. Swirl number ranges from 0(nonswirl jet) to 0.6 when the angle of swirl vane is 60 degree. As swirl becomes strong, the maximum velocity in the plane perpendicular to jet axis decreases fast and the uniformity of velocity becomes good, particularly in the ventilated area. The similarity in velocity profiles has been found for axial velocity from even when swirl number equals 0.6. The flow characteristics of the swirl-jet which has the swirl number of 0.6 is thought to be the best among these three swirl numbers for factory ventilation. However, the pressure drop in the diffuser increases as the swirl becomes strong. This should be considered in the design of the total ventilation system including a duct system.

• The KSFM Journal of Fluid Machinery
• /
• v.14 no.4
• /
• pp.25-30
• /
• 2011

The jet fan is generally used to add thrust in the longitudinal ventilation system of road tunnel and the geometric conditions of jet fan such as the distance from tunnel wall have an effect on the performance of ventilation system. Numerical analyses on the flow in tunnel caused by operation of jet fan are presented to study the ventilation characteristics in tunnel. While the distance between jet fans in parallel installed in tunnel is changed 0.5 L/D to 3.0 L/D, the flowrate and mean velocity through tunnel are calculated for each cases. As the distance between jet fans increases, the flowrate through tunnel increases asymptotically and the momentum of tunnel flow is alike.

• Proceedings of the KSLP Conference
• /
• 2011.03a
• /
• pp.19-19
• /
• 2011

• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.10-13
• /
• 2010

The flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, jet fan is one of main ventilation facilities especially in longitudinal ventilation system of tunnel. In this study to analyze tunnel flow induced by operation of jet fan, numerical simulation has been carried out. The velocity distributions and streamlines in tunnel are examined to consider the three-dimensional characteristics of tunnel flow caused by jet fan.