• 대한기계학회논문집B
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• 제32권7호
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• pp.513-517
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• 2008

A parametric study was made to understand the fundamentals of combustion of CNG fuel in a constant volume chamber in the respect of swirl effect, and the numbers of spark ignition. Optical devices were applied for the visualization of the physics of combustion, and combustion pressures and exhaust emission were measured at several equivalence ratios by controlling speeds of a swirling motor. When the speed of a swirling motor was raised the combustion conditions were improved. The corresponding maximum combustion pressure and heat release rate were increased and the speed of flame propagation was getting faster. This research may contribute to improve the performance of CNG engine and reduce emissions in future.

• 대한기계학회논문집B
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• 제27권1호
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• pp.39-45
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• 2003

As the size of a combustor decreases to a MEMS scale, heat loss increases and becomes a dominant effect on the performance of the devices. Existing models, however, are not adequate to predict the heat transfer and combustion processes in such small scales. In the present study, a semi-empirical model to calculate heat loss from a micro combustor is described. The model derives heat transfer coefficients that best fits the heat loss characteristics of a micro combustor that is represented by transient pressure record after combustion is completed. From conservation of energy equation applied to the burned gas inside the combustor, a relationship between pressure and heat transfer is reduced. Two models for heat transfer coefficients were tested; a constant and first order polynomial of temperature with its coefficients determined from fitting with measurements. The model was tested on a problem of cooling process of burnt gas in a micro combustor and comparison with measurements showed good agreements. The heat transfer coefficients were used for combustion calculation in a micro vessel. The results showed the dependence of flame speed on the scale of the chamber through enhanced heat loss.

• 한국항행학회논문지
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• 제18권2호
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• pp.107-113
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• 2014

본 논문에서는 무인항공기용 소형 터보제트엔진에 대해 압축기 서지현상 및 화염소실을 방지하면서 과도응답 특성을 개선하는 제어기를 설계하였다. 인공신경망과 PID 제어 알고리즘을 적용하는 터보제트엔진 제어기를 설계하고 인공신경망 역전파 알고리즘을 사용하였다. 터보제트 엔진의 가 감속 시 서지현상과 flame-out 현상을 방지하기 위해 연료 유량 제어 입력을 인공신경망 PID 제어기로 생성한다. 생성된 연료 유량 제어 입력은 신속하고 안전하게 원하는 속도로 수렴할 수 있도록 제어기를 설계한다. MATLAB을 이용한 시뮬레이션을 통해 이득 값에 따른 응답특성 비교 분석 및 신속하고 안전하게 원하는 속도로 수렴하는 제어성능을 확인하였다.

• 한국안전학회지
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• 제19권4호
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• pp.150-154
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• 2004

실린더형의 내용적 6리터의 용기를 이용하여 수소와 액화석유 가스(LPG)의 폭발 특성을 측정하였고 270리터의 직육면체 용기를 이용하여 폭발 후 화재로의 전이 현상을 실험하였다. 폭발 특성은 strain type 압력센서를 사용하여 측정하였으며 폭발 후 화재로의 전이 현상은 고속카메라로 촬영하여 분석하였다. 실험 결과 완전 연소 농도 비보다 약간 높은 농도에서 최대 폭발압력을 나타내었다. 폭발압력 상승 속도와 화염 전파속도는 연소속도와 비례함을 알 수 있었으며 이러한 폭발 특성들은 폭발 후 화재로의 전이에 영향을 미침을 알 수 있었다. 또한 폭발 화염온도, 화염의 용기 내 체류시간 등도 폭발 후 화재로의 전이에 중요한 변수가 됨을 알 수 있었다.

• 한국항공운항학회지
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• 제22권1호
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• pp.1-6
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• 2014

In this paper, controller propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Artificial Neural Network PID control algorithm and make an inference by applying Levenberg-Marquartdt Error Back Propagation Algorithm. Artificial Neural Network inference results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbojet engine for UAV. High Gain Observer is used to estimate to compressor rotation speed of turbojet engine. Using MATLAB to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.142-152
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• 2001

Three Lab-scale combustors of different types were made to observe some basic phenomena of fuel combustion in the combustors ; grate type combustor, rotary kiln and FBC. The aims were to introduce how to simulate the combustion behaviors in the real plants by utilizing the reduced apparatuses and characterize the combustors relating to some important parameters such as fuel size, water contents, bed temperature, rotating speed of kiln, flow rate. The mean carbon conversion time and the flame propagation rate were adopted for the quantitative analysis.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.245-251
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• 2005

Recently, fuel reforming technology for the fuel cell vehicle has been applied to internal combustion engines, with various purpose. Syngas which is reformed from fossil fuel has hydrogen as a major component. It has better effort in combustion characteristics such as wide flammability and hig speed flame propagation. In this study, syngas was added to a gasoline engine for the improvement of combustion stability and exhaust emission in idle state. Combustion stability, exhaust emissions, fuel consumption and exhaust gas temperature were measured to investigate the effects of syngas addition on idle performance. Results showed that syngas has ability to extend lean operation limit and ignition retard range. with dramatical reduction of engine out emissions.

• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.302-310
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• 1997

In this paper, we find a method to improve ignitability using methanol which is prospective as an alternative fuel. The constant volume combuster is divided into main chamber and sub-cham¬ber. These two chambers are linked by an adapter which is shaped like a cup. We also compare CDI to HIS that is revised in our laboratory for making a scrutiny into the effects of ignition char¬acteristics. Besides, we analyze a flame propagation process in the main and sub-chamber through taking pictures 10, 000 frames per second by high speed camera at the state being fabricated quartz glass aside main and sub-chamber.

• 센서학회지
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• 제19권2호
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• pp.67-86
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• 2010

Hydrogen is emerging as clean fuel and important industrial raw materials. The hydrogen gas is not sensed by the human olfactory system, But the combustion characteristics of hydrogen is that the ignition is very easy, the propagation speed of the flame is very fast and explosion limits is a wide range of 4 %~75 %. Therefore it is extremely in danger, and the need for its leakage detection technologies is especially important in places such as a production, transportation, storage and usage. The hydrogen sensors are classified with ceramic type, semiconductor type, optical type, electrochemical type and so on. Hydrogen sensors and their technologies are reviewed in detail for materials, fabrication process, sensing characteristics, good point and faults, and production and utilization of sensors be discussed.

• 오토저널
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• 제9권4호
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• pp.50-60
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• 1987

Combustion characteristics of opposed-jet-flames spouting out from dual prechambers of a divided combustion chamber were investigated by using high speed schilieren photography and chamber pressure measurement. Result shows that opposed-jet-flames are characterized by the parameter ( $A_{ori}$/ $V_{p}$) and there exists a certain critical value of ( $A_{ori}$/ $V_{p}$)c which distinguishes flame propagation patterns in the main chamber. Also higher chamber pressure and shorter total burning time can be derived by adopting this dual prechamber divided combustion chamber, which would lead a possibility of an appropriate combustion method of high load and low emissions.ons.ons.