• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3073-3078
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• 2008

In this study to find out the amount of soot, LII method, which utilizes a laser, was used in laminar diffusion flame and based upon the temperature and soot measured from the turbulent Diesel diffusion flame in the constant-volume chamber using the two-color method. Through these experiments, we could know that the LII signal is generally proportional to the soot amount in a laminar diffusion flame. And we could acquire the temperature and soot using the two-color method in a turbulent Diesel diffusion flame effectively. In addition to, this experiment revealed that the KL factor was high on parts of the chamber where the temperature dropped. On the other hand, the KL factor was low where the temperature increased rapidly. Also, it was possible to measure the highest temperature of a turbulent Diesel diffusion flame is approximately 2300K.

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2054-2060
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• 2011

본 연구의 목적은 경제적이고, 친환경적인 가솔린 직접 분사 인젝터의 분무특성을 연구하는 것에 있다. 분무도달거리, 분무각 그리고 혼합기 형성과 같은 인젝터의 특성을 가시화 실험을 통하여 측정하였다. 특히 분무압력과 분위기압력이 분무 침투거리와 분무각에 미치는 영향을 분석하였다. 가시화 실험을 위하여 정적 연소실과 연료 공급장치를 제작하였다. 초고속 카메라와 LED광원을 이용하여 분무형상을 촬영하였고, 촬영된 영상으로 분무 특성을 분석하였다. 연소실내의 분위기압력이 감소하고, 연료의 분무압력이 증가할수록 도달거리는 증가하였다. 분위기압력과 분무압력에 대해 분무각의 변화는 미소하지만, 분위기압력이 분무각에 더 큰 영향을 미치고 있다.

• 오토저널
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• 제14권4호
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• pp.31-38
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• 1992

The objective of this study is to determine the ignition feasibility of a single shot, air-assisted gasoline fuel injector operated in a constant volume combustion chamber under atmospheric condition. A number of parameters has been selected for this experiments, such as dwelling time, spark gap position(r,z), spark electrode geometry, supplied air and fuel masses and spray cone deflector angle. On-site visual inspection of the instantaneous flame glow was chosen as one way to judge the successful ignition. In addition, chamber pressure and occasional photography were mobilized as for data recording. It was clearly observed that there was an entrainment air-fuel mixture toward spray axis from the spray formation and its development later on. The optimum ignition conditions were found for those parameters given above.

• 대한기계학회논문집B
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• 제39권6호
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• pp.505-511
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• 2015

고체 산화물 연료전지는 $800{\sim}1000^{\circ}C$의 고온에서 작동한다. 고온 작동은 효율에 유리하지만 재료 요구 조건, 신뢰성, 열팽창 문제 등이 발생하여 온도 제어가 중요하다. 본 연구에서는 연료전지 시스템의 열관리를 위한 상태 공간 제어기를 설계하고 응답 특성을 확인하였다. 연료전지 스택과 열관리 핵심부품인 촉매연소기는 집중 용량법을 이용한 과도 응답 모델을 개발하였고, 구성품과 통합하여 정적 운전 특성을 확인하였다. 개발된 비선형 시스템을 정격 운전 조건에서 다중 입력과 출력이 가능한 상태 공간 식으로 선형화하였다. 부하에 따라 응답특성이 현저하게 달라지는 특성을 제어하기 위해 LQR 제어기를 설계하여 궤환 제어 시스템의 온도를 제어하였다. 상태 궤환 제어기가 적어도 두 개의 제어 게인을 가지고 운전 영역에 따른 응답을 보여줄 때, 원하는 온도 응답을 나타냄을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제25권6호
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• pp.636-642
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• 2014

As environment problem became a worldwide issue, countries are tightening regulations regarding greenhouse gas reduction and improvement of air pollution problems. With these circumstances, one of the renewable energies produced from biomass is getting attention. Bio-ethanol, which is applicable to SI engine, showed a positive effect on the PFI (Port Fuel Injection) type. However, Ethanol has a problem in homogeneous mixture formation because it has high latent heat of vaporization characteristics and in the GDI (Gasoline Direct Injection) type, mixture formation is required quickly after fuel injection. Particularly, South Korea is one of the countries with great temperature variation among seasons. With this reason, South Korea supply fuel additive for smooth engine operation during winter. Therefore, experimental study and investigation about application possibility of blending fuel is necessary. This paper demonstrates the spray characteristics by using the CVC direct injection and setting the bio-ethanol blending fuel temperature close to the temperature during each seasons: -7, 25, $35^{\circ}C$. The diameter and the width of the CVC are 86mm and 39mm. High-pressure fuel supply system was used for target injection pressure. High-speed camera was used for spray visualization. The experiment was conducted by setting the injection pressure and ambient pressure according to each temperature of bio-ethanol blending fuel as a parameter. The result of spray visualization experiment demonstrates that as the temperature of the fuel is lower, the atomization quality is lower, and this increase spray penetration and make mixture formation difficult. Injection strategy according to fuel temperature and bio-ethanol blending rate is needed for improving characteristics.

• 한국수소및신에너지학회논문집
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• 제29권2호
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• pp.219-225
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• 2018

This study was carried out to investigate the injection characteristics of 800 kPa compressed natural gas compressed natural gas (CNG) injector developed in Korea. The CNG injector with multi-holes, employed in this experiment, was designed to inject CNG in the manifold at high pressure of 800 kPa. The spray macroscopic visualization test was carried out via Schlieren photography to study fuel-air mixing process. The fundamental spray characteristics, such as spray penetration, spray cone angle and spray velocity, were evaluated in the constant volume combustion chamber (CVCC) with varying the constant back pressure in CVCC from 0 to 1.8 bar. For the safety reason, nitrogen ($N_2$) and an acetone tracer were utilized as a surrogate gas fuel instead of CNG. The surrogate gas fuel pressures were controlled at 3, 5.5, and 8 bar, respectively. Injection durations were set at 5 ms throughout the experiment. The simulating events of the low engine speed were arranged at 1,000 rpm. The spray images were recorded by using a high-speed camera with a frame rate of 10,000 f/s at $512{\times}256pixels$. The spray characteristics were analyzed by using the image processing (Matlab). The results showed the significant difference that higher injection pressure had more effect on the spray shape than the lower injection pressure. When the injection pressure was increased, the longer spray penetration occurred. Moreover, the linear relation between speed and time are dependent on the injection pressure as well.

• 한국분무공학회지
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• 제10권2호
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• pp.1-9
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• 2005

An experimental study was carried out to obtain the fundamental data about the effects of radical ignition on premixture combustion. A CVC(constant volume combustor) divided into the sub-chamber and the main chamber was used. Numerous narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in tile sub-chamber derives the simultaneous multi-point ignition in the main chamber. We have examined the effects of the sub-chamber volume, the diameter and number of passage holes, and the equivalence $ratio({\Phi})$ on the combustion characteristics by means of burning pressure measurement and flame visualization. In a CVC, the overall burning time including the ignition delay became very short and the maximum burning pressure was slightly increased by the radical ignition(RI) method in comparison with those by the conventional spark ignition(SI) method. Combustible lean limit by RI method is extended by ${\Phi}=0.25$ compared with that by SI method. Also, In cases of charging the number and the diameter for the fixed total cross section of the passage holes, combustion period increased significantly at a sub-chamber with a single hole, but those of the other conditions had almost a similar tendency in the sub-chamber with 4 or more holes. regardless of equivalence ratio. Therefore, it was Proved that a critical cross section exists with the number of passage holes.

• 공업화학
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• 제34권4호
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• pp.421-425
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• 2023

Polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), 그리고 polyacetal을 포함하는 일부 플라스틱류에 대한 연기특성을 조사하였다. 연기밀도는 ISO 5659-2의 기준에 의해 연기밀도시험기를 이용하여 정적인 연기 특성의 관련 값을 측정하였다. 또한 불꽃을 동반하는 연소와 불꽃을 동반하지 않는 연소를 구분하여 측정하였다. 불꽃방식의 복사열 50 kW/m² 의 조건하에서 연기의 최대비광학밀도(D_m) 측정값은 PMMA (401.26)가 최저로, PVC (1345.04)가 최대로 나타났다. 또한 비불꽃방식의 복사열 50 kW/m² 의 조건하에서 연기의 D_m 측정값은 PMMA (262.82) 가 최저로, PVC (1385.43)가 최대로 나타났다. 대상물의 연소 시 연기발생은 복사열 유속의 영향을 상당히 받으며, 탄화성 플라스틱은 연소 시 비탄화성 플라스틱보다 높은 연기 발생량을 나타내었다. 주 고분자 사슬에 방향족 그룹이 있는 폴리머는 열분해로 인해 다량의 숯이 생성되므로 다량의 연기를 발생시켰다.

• 한국화재소방학회논문지
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• 제31권2호
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• pp.37-43
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• 2017

이 연구에서는 4종의 삼나무, 스프러스, 나왕, 레드파인 시험편을 콘칼로리미터(Cone calorimeter, ISO 5660-1, 2)와 연기밀도시험기(ASTM E 662)를 이용하여 연소성을 시험하였다. 그 결과, 삼나무가 착화시간이 가장 빨랐고 평균열방출율($HRR_{mean}$)이 $58.52kW/m^2$으로 가장 낮게 나타났다. 그리고 레드파인의 평균열방출율($HRR_{mean}$)이 $71.75kW/m^2$으로 가장 높게 나타났다. CO 발생량에서는 나왕과 삼나무가 가장 많이 발생하였고, 반대로 $CO_2$ 발생량에서는 레드파인과 스프러스가 가장 많이 발생하였다. 동적방법에서의 총연기방출율은 레드파인이 연기가 가장 많이 발생하였고, 스프러스가 가장 적게 발생하였다. 정적방법에서의 연기밀도는 레드파인이 훈소(Non-flaming) 방식과 불꽃(Flaming) 방식에서 가장 높았다. 나왕은 훈소(Non-flaming) 방식에서 2번째로 연기가 많이 발생한 데 반하여 불꽃(Flaming) 방식에서는 가장 적게 발생한 것을 알 수 있었다. 열방출율 측면에서 화재위험성은 4가지 시험편 중 레드파인이 가장 높았다. 연기발생 관점으로 보아도 동적인 방식과 정적인 방식 모두 레드파인이 화재 위험성이 가장 높은 재료였다.

• 한국분무공학회지
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• 제21권1호
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• pp.29-36
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• 2016

The effect of high ambient temperature and pressure conditions on the combustion performance of n-butanol, n-heptane and its mixing fuel (BH 20) were studied in this work. To reveal this, the closed homogeneous reactor model applied and 1000-1200 K of the initial temperature, 20-30 atm of initial pressure and 1.0 of equivalence ratio were set to numerical analysis. It was found that the results of combustion temperature was increased and the ignition delay was decreased when the ambient conditions were elevated since the combustion reactivity increased at the high ambient conditions. On the contrary, under the low combustion temperature condition, the combustion pressure was more influenced by the ambient temperature in the same ambient conditions. In addition, the total mass and the mass density of tested fuels were influenced by the ambient pressure and temperature. Also, soot generation of mixing fuel was decreased than n-heptane fuel due to the oxygen content of n-butanol fuel.