• 한국연소학회지
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• 제20권1호
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• pp.6-14
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• 2015

Numerical study was conducted to clarify effects of added $H_2O$ for the downstream interaction between $H_2$-air and CO-air premixed flames in counterflow configuration. The reaction mechanism adopted was Davis model which had been known to be well in agreement with reliable experimental data. The results showed that both lean and rich flammable limits were reduced in increase of strain rate. The most discernible difference between the two with and without having $H_2O$ and/or $H_2$ addition into $H_2$-air and CO-air premixtures was two flammable islands for the former and one island for the latter at high strain flame conditions. Even a small amount of $H_2$, in which $H_2$-air premixed flame cannot be sustained by itself, participates in CO oxidation, thereby altering the CO-oxidation reaction path from the main reaction route $CO+O_2{\rightarrow}CO_2+O$ with a very long chemical time in CO-air flame to the OH-related reaction routes including $CO+OH{\rightarrow}CO_2+H$ with very short chemical times. This intrinsic nature alters flame stability maps appreciably. The results also showed that chemical effects of added $H_2O$ help lean flames at relatively low strain rate be sustained, and suppress the flame stabilization at high strain rates.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.66-70
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• 2001

The combustion characteristics have been investigated to develop the low $NO_{x}$ gas turbine combustor. The lean premixed combustion technology was applied to reduce the $NO_{x}$ emission. Also, the conventional combustor was designed and tested for the baseline of low $NO_{x}$ combustor performance. The test was conducted at the condition of high temperature and ambient pressure. The combustion air which has the temperature of 500K were supplied to the combustor through the air preheater. The temperature and emissions of $NO_{x}$ and CO were measured at the exit of combustor. The premixing chamber can be operated very lean condition of equivalence ratio around 0.35. The $NO_{x}$ was decreased with decreasing the equivalence ration. The CO was decreased with decreasing the equivalence ratio, but the CO was increased with decreasing the equivalence ratio below 0.45. But, at the very lean condition of equivalence ratio below 0.35 both NOx and CO were increased because of the flame unstability. The $NO_{x}$ was decreased slightly and CO was increased with increasing inlet air flowrate. This results can be used to determine the size of combustor. The low $NO_{x}$ combustor has lower values of $NO_{x}$ and CO compared with conventional one. Consequently the performance of combustor shows the possibility of the application to the gas turbine system.

• 한국항공우주학회지
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• 제30권6호
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• pp.1-6
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• 2002

마이크로 연소실을 장착한 MAV 추진 장치용 단기통 MEMS 엔진을 제작하였다. 본연구에서는 MEMS 크기의 왕복운동 내연기관의 타당성을 검증하고 실용화를 위한 설계 및 가공데이터를 축적하고자 하였다. 엔진 블록은 가공의 정밀도와 내열성등을 고려하여 감광유리 웨이퍼를 사용하였으며, 점화 전극은 베이스 플레이트 위에 니켈 도금으로 제작하였다. 감광유리판은 등방성 에칭의 특성이 탁월하여 마이크로 엔진의 실린더와 피스톤과 같이 비교적 깊은 식각이 가능함을 확인하였다. 전체 엔진은 세 개의 별도 가공된 레이어를 접착하여 조립한다. 본연구의 엔진 연소실은 깊이는 1mn, 폭 2mn이며, 피스턴은 수소-공기 예 혼합 가스의 연소압력에 의하여 구동된다. 가공된 엔진의 연소실험을 통하여, 점화, 화염전파 및 피스턴 구동을 확인하였으며, 실용화를 위한 연구가 요구되고 있다.

• 대한기계학회논문집B
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• 제36권3호
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• pp.251-257
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• 2012

본 연구에서는 이중원추형 버너가 장착된 고압연소기를 이용하여 입구공기온도, 공기비 그리고 연소실 압력조건에 따른 NOx 배출 특성을 실험적으로 조사하였다. 배기가스 온도와 NOx 배출량은 동일한 연소실 끝단지점에서 측정되었다. NOx 배출량은 공기비가 증가함에 따라 감소하는 경향을 나타내었으며, 입구공기 온도와 연소실의 압력이 높아질수록 증가하는 경향을 나타내었다. 특히 입구공기 온도의 증가는 희박 영역에서 가연한계를 증가시켜 높은 단열화염 온도를 가짐에도 불고하고 저감된 NOx 배출 수준을 얻을 수 있었다. 연소실 압력이 증가할수록 Thermal NOx의 영향을 받는 영역에서의 NOx 배출은 큰 폭의 상승을 보였으나, 공기비가 1.8이상인 영역에서는 적은 연료량으로 인하여 적은 상승폭을 나타내었다.