• 대한기계학회논문집B
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• 제24권12호
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• pp.1652-1661
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• 2000

A visualization study using the schlieren method is adopted in an optically-accessible, cylindrical constant volume combustion chamber to identify the mechanism of ignition energy and ignition system interaction in spark ignited, lean gasoline-air mixture. In order to research the effects of ignition system on flame propagation, two kinds of ignition system are designed, and several kinds of spark plugs are tested and evaluated. To control the discharge energy, the dwell time is varied. The initial flame development is quantified in terms of 2-D images which provides information about the projected flame area and development velocity as a function of ignition system and discharge energy. The results show that high ignition energy and extended spark plug gap can shorten the combustion duration in lean mixtures. The material, diameter and configuration of electrodes the flame development by changing the transfer efficiency from electrical energy to chemical energy and discharge energy. However these factors do not affect of flame development as much a ignition energy or extended gap does.

• 한국연소학회지
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• 제15권2호
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• pp.1-11
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• 2010

Power generation systems based on the oxy-coal combustion with carbon dioxide capture and storage (CCS) capability are being proposed and discussed lately. Although a large number of lab scale studies for oxy-coal power plant have been made, studies of pilot scale or commercial scale power plant are not enough. Only a few demonstration projects for oxy-coal power plant are publicized recently. The proposed systems are evolving and various alternatives are to be comparatively evaluated. This paper presents a proposed approach for performance evaluation of a commercial 100 MWe class power plant, which is currently being considered for 'retrofitting' for the demonstration of the concept. The system is configurated based on design and operating conditions with proper assumptions. System components to be included in the discussion are listed. Evaluation criteria in terms of performance are summarized based on the system heat and mass balance and simple performance parameters, such as the fuel to power efficiency and brief introduction of the second law analysis. Also, gas composition is identified for additional analysis to impurities in the system including the purity of oxygen and unwanted gaseous components of nitrogen, argon and oxygen in air separation unit and $CO_2$ processing unit.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.178-184
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• 2015

According to the regulation on the environment and fuel efficiency is becoming strict, many experiments are conducted to improve efficiency and emission in internal combustion engines. LTC (Low temperature combustion) technology is a promised solution for low emissions but there are a few barriers for the commercial engine. This paper includes optimization that applies LTC method to heavy duty diesel engine. Adequate LTC was applied to low and middle load as adaptability in heavy duty diesel engine, and optimization focused on reduction of fuel consumption was proceeded at high load. Through this research, strategy for practical use of LTC was selected, and fuel consumption has improved on the condition that satisfies the emission regulation at systematic viewpoint.

• 한국분무공학회지
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• 제9권2호
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• pp.9-17
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• 2004

The performance characteristics of lean burn system in gasoline engine are mainly affected by the air-fuel mixture in cylinder, gas exchange process of manifold system, exhaust emission of engine, and the electronic engine control system. In order to obtain the effect of performance factors on the optimum conditions of lean burn engine, this study deal with the behavior of mixture formation, gas flow characteristics of air, flow and evaporation analysis of spray droplet in cylinder, vaporization and burning characteristics of lean mixture in the engine, and the control performance of electronic engine control system. The optimum flow conditions were investigated with the swirl and tumble flows in the combustion chamber with swirl control valve. The performance characteristics and optimum condition of flow field in intake system were analyzed by the investigation of inlet flow of air and combustion stabilization on cylinder.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.222-229
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• 2005

공기 중의 이산화탄소가 10% 함유된 연소가스를 5단의 다단 농축 막분리 시스템을 이용하여 분리하는 것을 Aspen plus와 Excel을 이용하여 모사하였다. 분리된 이산화탄소의 농도는 99% 이상, 이산화탄소 제거 효율을 90% 이상으로 하였다. 이때 최적화 변수를 각 단의 압력, 각 단에서의 잔여물 농도로 하였고 각 단의 막 면적의 합과 막 분리시스템의 장치비와 운전비를 고려한 목적함수를 제안하여 최적화를 행하였다. 최적화 결과, 기존 설계에 비해 막 면적 및 총괄 소요비용을 절감할 수 있었으며, 이를 바탕으로 다단농축 막분리 시스템의 설계지침을 얻었다.

• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.446-453
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• 2000

The closed cycle diesel system is operated in closed circuit system where there is non air breathing with working fluid consisted of the combination of oxygen, argon and recycled exhaust gas for obtaining underwater or underground power sources. this study has been carried out to analysis the performance of closed cycle system by means of investigation on the combustion characteristics of diesel engine MTU8V183TE52 operating in open, semi-closed, and closed cycle modes. The combustion in closed mode starts a little bit earlier than in open cycle mode. The oxygen concentration and fuel consumption at 240kW closed cycle running are 21∼24% by volume and 77∼79kg/h, respectively. The maximum cylinder pressure and ignition delay time are investigated 110bar and 8.9degree. Also, The combustion simulation program has been studied to predict whether or not combustion. The results from numerical prediction for the basic, cylinder averaged quantities such as the cylinder pressure and the heat release showed excellent with the experimental data.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.206-209
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• 2010

하이브리드 로켓에서의 고체 연료의 연소 현상을 가시화하기 위하여 장치를 제작하였다. 가시화 장치는 평판 하이브리드 연소기 시스템, 점화 시스템, 산화제 공급 시스템, 데이터 획득 및 제어 시스템, 연소 가시화 측정 장비로 구성되었다. GOX 산화제와 HDPE, Paraffin-LDPE Blending, Paraffin 연료를 이용하여 연소 가시화 시험을 수행하였고, 수치적으로만 연구되어 왔던 연소실 내의 연소 현상을 가시화 할 수 있었으며, 화염의 형성 및 용융성 연료의 액적 비산 현상을 관찰 할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권7호
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• pp.713-721
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• 2005

A marine diesel engine should realize optimal operation efficiency while reducing NOx, PM (Particulate Matters) and other emissions. Fuel injection systems that use electronic control can become an effective means of achieving that objective. However. it still needs some accurate and instant information in order to bring its ability into full potential while sailing on the sea. The important information of them are a shaft torque and continuous combustion pressures of all cylinders. The shaft torque and the propeller thrust described in this paper are measured at an intermediate shaft by using a unique principle that one of two electromagnet coils oscillates a vibrating strip which the length changes with force and the other coil picks up the change of the frequency of the vibrating strip. For further reference, the shaft power meter multiplied the torque by the shaft revolution has already had about 750 sets of sales performance. The research presented in this paper started about ten years ago and is concerned with the development of a combustion pressure sensor that uses the same principle. Recently, the pressure sensor which bears continuous operation has been developed after a hard struggle, that is, the system that consists of a shaft horsepower meter, a propeller thrust meter and a combustion pressure sensor has been completed and has been shown to be reliable. This paper describes the configuration of this system, the material of the combustion pressure sensor, the principle of that, and the improving point of the sensor, and, we finally consider the use of this system.

• 에너지공학
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• 제12권1호
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• pp.1-10
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• 2003

가압유동층 연소 유닛은 1~1.5 MPa, 연소 온도 850~87$0^{\circ}C$ 조건으로 운전된다. 가압 석탄 연소 시스템은 전열관을 통한 열전달로 증기를 생산하며 가스터빈으로 공급될 고온 가스를 생산한다. 가스 중의 고체 잔류물에 의한 가스터빈의 성능 저하 때문에 가스 정제가 매우 중요하며 석탄과 흡수제 및 연소 공기를 가압하여야 하고 배가스와 회 제거 시스템에서는 감압을 해야 하기 때문에 운전이 다소 복잡하다. 증기터빈 대 가스터빈에서 생산되는 전력의 비율은 약 80:20이고 모든 부하 범위에서 연소기와 가스터빈이 서로 적절히 조화를 이루어야 하기 때문에 PFBC와 복합 사이클 발전 루트는 독특한 제어 방식을 갖는다. 유동층에 적용할 수 있는 가스의 최대 온도는 회 융점에 의해 제한을 받기 때문에 가스터빈은 일반 가스터빈에 비해 좀 특별하다고 할 수 있다. 회의 용융이 일어나지 않도록 하기 위한 최대 허용 가스 온도는 약 90$0^{\circ}C$이다. 가스터빈의 높은 압력비 때문에 압축시 인터쿨링을 사용하며 이는 상대적으로 낮은 터빈 입구의 온도를 상쇄하기 위한 것이다.

• 대한기계학회논문집B
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• 제36권2호
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• pp.211-216
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• 2012

화석 에너지 고갈에 따라 에너지의 합리적 이용이 요구되면서 가용 에너지를 고려한 열에너지의 계단식 활용이 적극적으로 검토되고 있다. 이와 같은 배경에서 1 kW 급의 스털링 엔진을 기반으로 한 열병합발전 시스템이 분산 에너지 시스템을 구축하는 단위로서 제안되었다. 1 kW 의 용량은 가정용에 적합하며, 가정에서 활용하기 위해서는 공간을 작게 차지하도록 하면서도 소음과 유해가스의 배출을 철저하게 차단해야 한다. 이러한 조건들을 충족시키며 효율이 높은 시스템을 개발하기 위하여 슬롯 형태의 예혼합 버너를 제안하였고 버너의 연소 특성을 파악하기 위하여 일련의 실험을 수행하였다. 본 연구에서는 화염의 형상을 촬영하여 연소부하 및 공기비에 따른 연소 모드를 관찰하였고 배가스를 분석하여 연소 모드에 따른 배기 특성을 연구하였다.