• 도시과학
• /
• 제9권2호
• /
• pp.13-20
• /
• 2020

The Recently, several countries have been affected by respiratory diseases, resulting in renewed research interest in their prevention and control. One such example was the 2015 outbreak of Middle East Respiratory Syndrome (MERS) in South Korea and COVID-19. In this study, we performed experiments and simulations based on concentration decay using CO2 as the tracer gas to elucidate the pollutant-removal efficiency for different inlet and exhaust locations and outdoor air-supply ratios. The wall inlet exhibited a higher pollutant-removal efficiency, owing to the upward movement of the air from the lower zone to the upper one. In conclusion, it is recommended that a total air-conditioning plan for isolation rooms be established as well as efficient system operation for pollutant removal and air-flow control to prevent the transmission of infections from the patients to others.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.95-95
• /
• 2010

In recent, there are tremendous requirements to improve the fuel economy of vehicle. For satisfaction of requirements, Hybrid Electric Vehicle or other technologies are suggested and implemented. However, it should be noted that almost 35% energy loss is occurred in the shape of exhaust gas as ever. For increase the efficiency of vehicle, it is certain that the exhaust gas energy should be recover, and generate energy. In previous studies, the technologies such as turbo-compound, thermoelectric and rankine cycle are suggested to recover the exhaust heat energy in vehicle. But, they focus on the conventional vehicle or parallel Hybrid Electric Vehicle. Series Hybrid Electric Vehicle has advantage that the engine and drive shaft are de-coupled. It means that the engine can be operated in high efficiency area regardless with vehicle states. Therefore, if rankine cycle is applied to series hybrid electric vehicle, operating condition of that becomes almost steady. So, in this study, theoretical analysis on the efficiency of rankine cycle applied to series hybrid electric city bus is carried and the energy recovered from exhaust gas during vehicle drive cycle is calculated.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
• /
• pp.290-297
• /
• 2002

This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as cumbined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency by adopting air flow modulation was analyzed and it is concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

• 한국유체기계학회 논문집
• /
• 제6권3호
• /
• pp.28-35
• /
• 2003

This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as combined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency of the combined cycle by adopting air flow modulation was analyzed and it was concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

• 산업기술연구
• /
• 제26권A호
• /
• pp.39-46
• /
• 2006

As an automobile fuel, LPG has many environmental advantages compared to gasoline or diesel. However, current LPG engine which is provided with LPG fuel as gas form has lower power and worse fuel efficiency than gasoline engine. These problems of low power and bad fuel efficiency come from lower volumetric efficiency. Also there is a new rising problem of high failure ratio in an engine emission test. Although there are many factors which affect engine performance of exhaust gas emission, one believes that the fact that ECM of gasoline engine is used for LPG engine when retrofitting gasoline engine to LPG engine is one of the main problems, which lower engine power and emit more noxious gas due to wrong ignition timing. To solve these problems, one studied the effects of ignition timing on the exhaust gas to find out the optimum condition of ignition timing. The experimental results show that noxious exhaust gas is reduced and engine power is increased if the optimum control of ignition timing is applied in accordance to the revolution speed of engine.

• 대한기계학회논문집B
• /
• 제27권7호
• /
• pp.837-844
• /
• 2003

The exhaust gas flow in the inlet collector of close coupled catalyst(CCC) adapted to the exhaust manifold is very complex flow because the exhaust gas is a pulsation flow with several port flow. The distribution of gas flow and temperature in inlet collector effect to the efficiency of catalytic converter. In this study, it measures temperatures on several point in inlet collector with two kind of inlet collector volume. And it analyzes with CFD to exhaust manifold and close coupled catalyst for temperature and flow. Comparing to measured and analyzed result, it find increasing of collector volume effects to catalyst temperature distribution and uniformity of catalytic converter

• 에너지공학
• /
• 제23권2호
• /
• pp.114-118
• /
• 2014

The need to maximize the exhaust pipe inside surface and to minimize exhaust resistance And Find the best point between the exhaust and the duration of contact between the two surfaces. Exhaust gas mass flow On the whole cross section of catalytic converters more uniform distribution will contribute to its usability. Based on the flow rate of fluid traces given color, Exhaust fluid resistance in the porous catalyst can be estimated, from the efficiency of the catalytic converter that is very important.

• 한국정밀공학회지
• /
• 제22권5호
• /
• pp.138-143
• /
• 2005

Recently, automobile manufacturers regarding stability, economic environmental-friendly problems by the development of automobile, environmental problem as designing the exhaust system. Increasingly strict environmental regulations to lower fuel consumption and reduce emission. Also to reduce the noise and the vibration of the automobile. According to develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption rate demand information of pressure fraction and heat characteristics. To be able to determine these factor for we experiment on each case of exhaust system unit. In this study, how back pressure is distributed in flow-through in exhaust system and how to design exhaust system flexibleness, efficiency and combustion charateristics influenced by back pressure. This study furnish basic data for engineers, technicians.

• 한국산학기술학회논문지
• /
• 제12권10호
• /
• pp.4302-4307
• /
• 2011

최근에 연비향상을 위해 다양한 기술들이 개발 중에 있다. 본 연구의 목적은 배기열 재순환장치의 열교환 성능을 평가한 후 최적 성능의 모델을 제안하는데 있다. 이 장치는 버려지는 배기열을 이용하여 가능한 한 빠르게 엔진 냉각수를 웜업 시키도록 설계하였다. 이 목적을 달성하기 위하여 CFD를 이용하여 냉각수의 흐름 방향과 냉각수의 유입 유출 위치에 따른 열유동 특성을 분석하고, 열교환 효율을 상승시키기 위한 방법을 제시하였다. 그 결과 냉각수 유량이 적고, 배기가스와 냉각수의 유로를 각각 구성하여 배기가스의 열이 직접적으로 냉각수에 영향을 미치는 구조가 가장 열교환 효율이 좋은 것으로 나타났다.

• 동력기계공학회지
• /
• 제13권4호
• /
• pp.11-17
• /
• 2009

This paper deals with the effects of pulsating flow on volumetric efficiency, which may be generated during the gas exchange procedure, due to piston motion, valve event on intake and exhaust stroke and unsteady flow of turbocharger of a three-cylinder four stroke turbo-charged diesel engine. Consequently, volumetric efficiency affects significantly the engine performance; torque characteristics, fuel economy and further to emission and noise level. As the expansion ratio became larger the engine speed varies and torque increases, the pressure pulsation in an exhaust gas pipe acts as an increasing factor of intake air charging capacity totally. The phase and amplitude of pressure pulsation in the intake system only affects volumetric efficiency favorably, if it is well matched and tuned effectively to the engine. Thus, to verify the exact phase and amplitude of the pressure variation is the ultimate solution for the air-flow ratio assessment in the intake stroke. Some experimental results of pressure diagrams in the intake pipe and gas-flow of turbine in-outlet are presented, under various kinds of operating condition.