• 설비공학논문집
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• 제26권11호
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• pp.535-540
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• 2014

This paper investigates the exhaust effectiveness of smoke, in the case of fire in a large atrium space. Numerical analysis was conducted to simulate transient fire growth in a test room, modeled by the Murcia atrium fire test. Various indices representing the exhaust performance of the exhaust system were obtained, such as the height of the smoke layer, and the instantaneous and accumulative capture efficiency of the smoke. The residual life time of smoke from the fire was also obtained, by injecting tracer gases at the fire location, depending on the airflow rate, and the location of the exhausts. The capture efficiency based on smoke concentration at the exhausts exhibits how much smoke can be removed by the exhaust system; whereas, the exhaust effectiveness based on residual life time indicates how rapidly the smoke can reach the exhaust locations, before being exhausted. The definitions and meanings of the indices to be used in representing the exhaust performance of a smoke exhaust system installed in a large space are discussed.

• 설비공학논문집
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• 제10권6호
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• pp.658-665
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• 1998

This paper investigates local exhaust effectiveness in a room with a supply and an exhaust slots on the ceiling. The mean age of air is an indicator of supply effectiveness, while the mean residual life time can be used as an indicator of exhaust effectiveness. The distribution of local mean residual life time in a space is calculated by four different numerical procedures. The reverse-flow calculation method has been proved to show quite accurate results while it can save considerable amount of computation time and efforts, compared to the method by its original definition. It is concluded that the diffusion term in the equation of mean residual life time can be neglected. The spatial and temporal diffusion characteristics of the contaminant are also discussed.

• 설비공학논문집
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• 제13권9호
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• pp.853-859
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• 2001

A pulsed tracer gas technique is applied to measure distributions of local mean age and residual life time of air in a half-scale experimental chamber. The room airflow patterns are flow-visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is either at bottom-left(Case 1), bottom-right(Case 2), or top-left(Case 3) location. Results show that the distribution of LMA and LMR are different from each other, but both of them are closely related to the airflow pattern in the space. Results on overall room ventilation effectiveness are provided depending upon ventilation airflow rates for three different supply-exhaust configurations.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.177-183
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• 2002

A pulsed tracer gas technique is applied to measure the distributions of local mean age and local mean residual-life-time of air in a half-scale experimental chamber, The airflow patterns in the chamber are visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is at either bottom-left (Case 1), bottom-right (Case 2), or top-left (Case 3) location. Results show that the distributions of local mean age and local mean residual-life-time are different from each other, but both of them are closely related to the airflow pattern in the space. Included are discussions on explaining the variations of overall room ventilation effectiveness depending upon airflow rates for three different supply-exhaust configurations.

• 한국기계가공학회지
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• 제12권1호
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• pp.43-51
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• 2013

This is a thesis about the experiment of comparison characteristic of power and exhaust gas in the same condition between diesel engine that is equipped turbocharger different from response power to increase effectiveness of the engine which is recently used in a lot of industry which requires high power. Resulting of the experiment with natural aspiration diesel engine and turbocharger diesel engine, difference in low speed is not significant, but in high speed, effectiveness of turbocharger diesel engine is much higher than the other one. In other hand, in exhaust gas experiment, turbocharger model exhausts more $NO_X$ and $O_2$, but it doesn't significantly affect the result when it comes with decreasing of $CO_2$ and effectiveness of increased power characteristic. As a result, the turbocharger diesel engine is economically effective comparing with the natural aspiration diesel engine.

• 한국기계가공학회지
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• 제11권6호
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• pp.100-106
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• 2012

This is a thesis about the experiment of comparison characteristic of power and exhaust gas in the same condition between diesel engine that is equipped turbocharger to increase effectiveness of the engine which is recently used in a lot of industry which requires high power. Resulting of the experiment with natural aspiration diesel engine and turbocharger diesel engine, difference in low speed is not significant, but in high speed, effectiveness of turbocharger diesel engine is much higher than the other one. In other hand, in exhaust gas experiment, turbocharger model exhausts more NOX and $O_2$, but it doesn't significantly affect the result when it comes with decreasing of $CO_2$ and effectiveness of increased power characteristic. As a result, the turbocharger diesel engine is economically effective comparing with the natural aspiration diesel engine.

• 터널과지하공간
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• 제20권4호
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• pp.277-283
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• 2010

본 연구에서는 지하공간에서 화재 발생 시 배연장비의 연기배출 성능을 평가하기 위하여 실험을 실시하였다. 배연장비로는 일선 관서에서 사용 중인 배연차를 사용하였다. 실험은 재개발 예정 지하 노래방에서 수행되었다. 배연차의 가동에 따라 실내 온도분포 및 연기농도를 측정하였다. 배연차를 가동함으로 인하여 복도에서 온도가 $50^{\circ}C$ 이하로 감소하였으며 가시도 또한 향상되었다.

• 한국터널지하공간학회 논문집
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• 제5권4호
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• pp.389-400
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• 2003

본 연구는 지하철방재대책의 일환으로 터널구간에 설치된 환기기의 제연절환 운전모드 및 승강장 선로부 환기장치를 포함한 6종류의 제연운전모드를 대상으로 승강장에 정차된 열차화재 시나리오에 따라 3차원 실시간 화재 시뮬레이션을 수행하여 제연방식별 열 및 연기전파특성을 규명함으로서, 승강장에서 열차 화재 발생시, 승객이 안전하게 최적 대피가 가능한 환기기의 제연절환 조합운전의 도출을 목표로 한다.

• 설비공학논문집
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• 제3권2호
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• pp.131-141
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• 1991

A method of optimum design of an axial rotary sensible heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of economics of investment cost and profit according to the installation of heat exchangers. Leakage rate of exhaust gas was calculated and the correlation for the pressure drop due to leakage of exhaust gas was proposed. Heat transfer between the matrix and exhaust and intake gas was analysed to calculate the effectiveness of heat exchanger, which was used for the optimum design of rotary heat exchanger. The results show that optimum rotational speed increases as the length of rotor increases and there exists optimum NTU which maximizes the gain of total cost according to the installation of rotary heat exchanger.

• 한국지열·수열에너지학회논문집
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• 제12권1호
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• pp.1-6
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• 2016

Characteristics of exhaust from chimney of electricity generator are analyzed based on CFD when Waveguide-Below-Cutoff (WBC) array is installed in order to achieve the certain level of electromagnetic pulse (EMP) shielding. The main purpose is prediction of average and maximum velocity of exhaust. The results reveal that: 1) When the specification of waveguide is given as 80-diameter, 400-length, and the gap of 20 mm, the shielding effectiveness (SE) is 140dB. The average and maximum velocity of exhaust in the chimney with WBC Array can be represented as exponential functions. 2) As the number of WBC increases, the velocity in the chimney dwindles. 3) Under the situation that WBC with 80 mm diameter is located at intervals of 20 mm, the average velocity can be approximated by $25.5344{\times}e^{(-0.0098{\times}N_{WBC})}$ with input velocity of 15 m/s. In addition, the determination coefficient is 0.915, which is sufficiently high.