• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2524-2527
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• 2007

Solid propellant gas generators (SPGG) play a role as a turbopump starter in liquid propellant propulsion systems by supplying pressurized gas to power turbines for engine start. For such a purpose, the propellants should burn with a relative low flame temperature and the combustion gas should not contain corrosive constituents such as chlorine compounds. In accordance with these requirements, stabilized AN-based propellants have been usually used as the most appropriate oxidizer for propellant compositions. However, the burning area of the propellant intends to increase to satisfy the required mass flux because of its low burning rate. Consequently the burning area incensement brings on the SPGG size augmentation. A flow restriction such as filters is applied to decrease the SPGG size by rising up the combustion pressure resulting in increasing the burning rate. The feasibility of the size reduction of SPGG by the employment of filters have been studied. The preliminary results of this study show that the considerable reduction of SPGG size would be achievable just by installing a filter with relatively high pressure loss coefficient.

• 한국분말재료학회지
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• 제10권2호
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• pp.108-117
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• 2003

WC and dense WC-10 vol%Co materials with grain size of~1${\mu}m$ were synthesized by high-frequency induction heated combustion synthesis (HFIHCS) method in one step from elemental powders of W, C and Co within several minutes. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. In the absence of cobalt additive, WC can be formed, but its relative density was low (about 73%) under simultaneous application of a 60 MPa pressure and the induced current. However, in the presence of 10 vol.%Co, the relative density increased to 99% under the same experimental condition. The percentages of the total shrinkage occurring before and during the synthesis reaction of WC-10 vol.%Co were 5% and 51%, respectively. The fracture toughness and hardness values of WC-10 vol.%Co were 10 MPa . m$^{1/2}$ and 1840 kg/$mm^2$, respectively.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.447-448
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• 2008

The goal of this study is to find flame dynamic behavior using a transverse fuel injection in a model combustor, and is to investigate main causes of unstable combustion in a liquid-fueled combustor. For transverse fuel injection into air cross flow, spray result shows similar tendency with Wu et al.[1998] until spray arrives at flame-holder. However, passing through flame-holder, fuel inflow into recirculation region of flameholder is not sufficient so it makes large difference between shear flame and recirculation flame behind flameholder. In combustion tests, the stable flame shows a kind of shear flames and low peaks of dynamic pressure frequencies. On the other hand, unstable flame shows periodic detached flame in recirculation zone and a strong peak of dynamic pressure frequency. The instability frequency is highly affected by influx air velocity, air temperature, equivalence ratio and wake or vortex shedding frequency behind the flameholder.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.41-42
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• 2006

A study on the combustion characteristics by using Emulsion Fuel in Diesel Engine is performed experimentally. In this paper, the experiments are performed at engine speed 1800rpm, emulsion fuel ratio is 0%, 10%, 20%, and main measured items are specific fuel consumption, pressure, ratio of pressure rise, rate of heat release etc. The obtained conclusions are as follows. 1) Specific fuel consumption increase maximum 19.8% at low load, but is not effected at full load. 2) Ratio of pressure rise and rate of heat release are about the same in the case of 10% and 20% of emulsion fuel ratio. 3) Cylinder Pressure increase 11.7%, ratio of pressure rise increase 60.4% in case of emulsion fuel ratio 20% at full load. 4) Rate of heat release increase 76.9% in case of emulsion fuel ratio 20% at full load.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.243-246
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• 2008

하이브리드 연소에서 연소실 압력에 따른 고체 연료의 연소 특성을 실험적으로 연구하였다. 본 연구는 낮은 산화제 평균 질량 유속구간에서 고체 연료 후퇴율이 산화제 유속 뿐만 아니라 연소실 압력에 영향이 있는지 실험적으로 확인하였다. 연료로 Poly-Ethylene과 산화제로 GOX를 이용하였으며, 동일 산화제 유속에서 연소실 압력 변화는 6mm,9mm의 노즐 목 직경으로 사용하였다. 낮은 산화제 질량유속구간에서 고체연료 후퇴율이 산화제 유속뿐만 아니라 압력에 의한 영향이 있고, 동일 산화제 유속에서 압력이 증가 할수록 후퇴율이 증가함을 확인 하였다.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1172-1177
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• 2004

The emission control of automobile has been intensified as a part of the countermeasure to decrease air pollution in the world. As the cars with an alternative fuel starts to get into the spotlight, the cars with low emission has been introduced and exhaust gas regulation forced in this country. These days, LPG vehicles, which infrastructure of fuel was already built up, and CNG vehicles are recognized for alternative fuel cars in this country. In this study, the constant volume combustion chamber was manufactured and used for experiments to obtain the combustion characteristics of propane mixture. The combustion characteristics was analyzed, with the change of supply conditions of propane fuel. Inside the combustion chamber, the maximum temperature increase with the initial pressure is going up. The burning velocity also seems to have the same characteristic as the temperature. However, the heat flux do not change much according to the theoretical correct mixture but it changes with the various initial temperature of the combustion chamber.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.30-39
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• 2017

Interests in fuel cell based power generation systems are on the steady rise owing to various advantages such as high efficiency, ultra low emission, and potential to achieve a very high efficiency by a synergistic combination with conventional heat engines. In this study, the performance of a hybrid system which combined a molten carbonate fuel cell (MCFC) and an indirectly fired micro gas turbine adopting carbon dioxide capture technologies was predicted. Commercialized 2.5 MW class MCFC system was used as the based system so that the result of this study could reflect practicality. Three types of ambient pressure hybrid systems were devised: one adopting post-combustion capture and two adopting oxy-combustion capture. One of the oxy-combustion based system is configured as a semi-closed type, while the other is an open cycle type. The post-combustion based system exhibited higher net power output and efficiency than the oxy-combustion based systems. However, the semi-closed system using oxy-combustion has the advantage of capturing almost all carbon dioxide.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.49-56
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• 2006

The single droplet combustion characteristics of multicomponent fuel such as diesel-oxygenate and diesel-paraffin blends under high ambient temperature and atmospheric pressure were investigated in the study. The results of the study may be concluded as follows : In the combustion of diesel fuel droplet with additive of oxygenate and paraffin, the dimensionless droplet size of $(D/D_o)^2$ was linearly decreased with time. A fuel droplet with low boiling temperature additives and in high boiling temperature diesel fuel evaporates and burns faster than usual diesel fuel. This rapid burning may result from so-called "micro-explosion" and its burning intensity varies with the types of additives. The results above may suggest that rapid evaporation of oxygenate additive in the middle stage of combustion can contribute much to combustion improvement of blended fuels. When compared to ordinary diesel fuel, neat oxygenate and paraffin fuels show blue flame during entire combustion which prove smokeless combustion.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3383-3388
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• 2014

본 연구는 4실린더 커먼레일 디젤 기관에서 바이오디젤 혼합 연료와 순수한 디젤연료를 사용하여 EGR율을 변화시켰을 때 연소 및 배기 특성을 디젤 연료만을 사용하였을 경우와 비교하기 위하여 실험을 수행하였다. 본 연구에서는 일반적으로 많이 사용되고 있는 기관 회전 속도 2,000rpm에서 바이오디젤 혼합율 20%의 연료와 디젤 연료를 사용하여, EGR율에 다양하게 변화를 주어 실험을 하였다. 실험결과, 연소압력은 바이오디젤 혼합 연료와 디젤 연료 모두 EGR율이 증가할수록 감소하였으며, 도시 평균유효 압력은, 디젤 연료에 비하여 바이오디젤 혼합 연료가 더 높게 나타났다. 배출가스의 경우에, NOx는 EGR율이 증가할수록 디젤 연료에 비하여 바이오디젤 혼합 연료가 더 많이 배출되었다. 또한 NOx는 바이오디젤 혼합 연료와 디젤연료 모두 EGR율이 증가할수록 감소되었다. CO와 Soot, $CO_2$는 EGR율이 증가 할수록 증가하였으며, CO, Soot은 디젤 연료에 비해 바이오디젤 혼합 연료에서 더 작게 배출되었지만 $CO_2$는 더 많이 배출되었다.

• 대한기계학회논문집B
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• 제34권5호
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• pp.449-456
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• 2010

HCCI 엔진은 고효율, 저공해를 실현할 수 있는 차세대 내연기관이다. 그러나 HCCI 엔진이 상용화되기 위해서는 몇 가지 문제점들이 해결되어야 한다. 그 중에서 가장 큰 문제점은 과도한 압력 상승률이 노킹을 발생시키기 때문에 운전영역이 제한되는 것이다. 이번 연구의 목적은 HCCI 엔진에서 압력상승률 저감을 위하여 온도 성층화와 농도 성층화 효과를 조사하는 것이다. 그리고 Multi-zone 모델을 이용한 화학반응 수치해석을 통하여 연소 및 배기가스 특성에 미치는 영향을 알아보았다. 수치해석에서 2 단계 열발생을 가지는 DME와 1단계 열발생을 가지는 메탄을 사용하였다.