LFG 혼합연료의 화염 안정화 특성

이창언,황철홍,김선호,Lee, Chang-Eon,Hwang, Cheol-Hong,Kim, Seon-Ho 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.2

In this study, experiments were performed to investigate the characteristics of flame stabilization of the LFG mixing gas. LFG has merely half heating value compared with liquified natural gas but can be greatly utilized as a commercial fuel. In order to use LFG in practical combustors, Webbe Index and heating value of LFG mixing gas were adjusted by mixing LPG with LFG. The comparisons were conducted between CH$_4$and LFG mixing gas for searching the region of flame stabilization based upon the flame blowout at maximum fuel stream velocity. As a result, the flame stability of LFG mixing gas was not improved with that of CH$_4$in non-swirl and weak swirl diffusion flame. However, LFG mixing gas had wide flame stabilization region rather than CH$_4$with increasing ambient flow rate in strong swirl. It was also found that flame stability was affected by included quantity of inert gas such as CO$_2$in the weak swirl but by heating value of fuel in strong swirl.

주기적인 좁은 슬릿을 갖는 소형화된 하이브리드 Rat-Race 결합기

이창언,이진택,김상태,신철재,Lee Chang On,Lee Jin-Taek,Kim Sang-Tae,Shin Chull-Chai 대한전자공학회 2004 電子工學會論文誌-TC (Telecommunications) Vol.41 No.12

In this paper, we introduce the concept of ILCTL(inductively loaded compact transmission line) that is new type of compact transmission line. ILCTL was realized by periodic narrow transverse slits working as series inductances in microstrip line. And compact hybrid rat-race couplers were designed by using the proposed ILCTL. The microstrip line hybrid rat-race coupler with silts of 8 per quarter wavelength at 1.8 GHz has reduced size of 60% as compared with conventional one and it is proved by simulation of EM solver with full-wave analysis based on MoM and measurements. 본 논문에서는 마이크로스트림 전송선로에 주기적으로 삽입된 좁은 폭의 슬릿을 이용하여 물리적 길이가 소형화되는 전송 선로인 ILCTL(inductively loaded compact transmission line)을 소개하였다. 주기적으로 부가된 좁은 폭의 슬릿은 마이크로스 트립 전송선로에서 직렬로 부가되는 인덕턴스 역할을 함으로써 전송선로의 길이를 소형화한다. 그리고 이러한 ILCTL을 이용하여 소형화된 rat-race 결합기를 구현하였다. 1.8 GHz에서 구현된 소형화된 rat-race 결합기는 일반적인 구조에 비해 60%의 크기를 가짐을 MoM(methods of moments)기반의 full-wave analysis를 이용한 2.5D EM(electromagnetic) solver의 계산과 제작 및 측정을 통하여 확인하였다.

수치계산을 이용한 LFG 혼합연료의 연소속도 상관식에 관한 연구

이창언,오창보,정익산,Lee, Chang-Eon,O, Chang-Bo,Jeong, Ik-San 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.11

In this study, the burning velocities of LFG and LFG mixed fuels have been numerically determined. C3 reaction mechanism involving 92 species and 621 reactions was adopted in the calculation. The computed burning velocities using C3 mechanism show good agreements with experimental data. Based on numerical results, the maximum burning velocities of LFG and LFG mixed fuels were correlated as a function of CH$_4$ and LFG component percentage at stoichiometric conditions. In addition, the correlations of burning velocities of LFG and LFG mixed fuels were obtained over a wide range of the equivalence ratio. The numerical results are well agreed with the burning velocity correlations. The burning velocity correlations for LFG and LFG mixed fuels suggested in this study can be applied to the practical utilization of LFG.

비정상 CH$_4$/공기 제트 확산화염에 관한 수치모사

이창언,오창보,Lee, Chang-Eon,O, Chang-Bo 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.8

The dynamic structures of unsteady CH$_4$/Air jet diffusion flame with a flame-vortex interaction were numerically investigated. A timed-dependent, axisymmetric computational model and a low mach number approximation were employed in the present calculation. A two-step global reaction mechanism which considers 6 species, was used to calculate the reaction rates. The predicted results including the gravitational effect show that the large outer vortices and the small inner vortices can be well simulated without any additional disturbances near nozzle tip. It was found that the temperature and species concentrations have deviated values even for the same mixture fraction in the flame-vortex interaction region. It was also shown that the flame surface is not deformed by the inner vortex in upstream region, while in downstream region, the flame surface is compressed or stretched by the outer vortex roll-up. The present unsteady jet flame configuration accompanying a flame-vortex interaction is expected to give good implications for the unsteady structures of turbulent flames.

산화제 제어 확산화염의 화염구조 및 NO 생성 특성에 관한 수치해석적 연구

이창언,한지웅,Lee, Chang-Eon,Han, Ji-Ung 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.5

Numerical Study with detailed chemistry has been conducted to investigate the flame structure and NOx formation characteristics in oxygen -enhanced(CH$_4$/O$_2$-$N_2$) and oxygen-enhanced-EGR(CH$_4$/O$_2$-$CO_2$) counter diffusion flame with various strain rates. A small amount of $N_2$is included in oxygen-enhanced-EGR combustion, in order to consider the inevitable $N_2$contamination by $O_2$production process or air infiltration. The results are as follows : In CH$_4$/O$_2$-$CO_2$flame it is very important to adopt a radiation effect precisely because the effect of radiation changes flame structure significantly. In CH$_4$/O$_2$-$N_2$flame special strategy to minimize NO emission is needed because it is very sensitive to a small amount of $N_2$. Special attention is needed on CO emission by flame quenching, because of increased CO concentration. Spatial NO production rate of oxygen-enhanced combustion is different from that of air and oxygen-enhanced-EGR combustion in that thermal mechanism plays a role of destruction as well as production. In case CH$_4$/O$_2$-$CO_2$flame contains more than 40% $CO_2$it is possible to maintain the same EINO as that of CH$_4$/Air flame with accomplishing higher temperature than that of CH$_4$/Air flame. EINO decreases with increasing strain rate, and those effects are augmented in CH$_4$/O$_2$flame.

주기적인 계단형 스터브를 갖는 소형화된 하이브리드 Branch-Line 결합기와 Rat-Race 결합기

이창언,김원기,김상태,신철재,Lee Chang On,Kim Won-Ki,Kim Sang-Tae,Shin Chull-Chai 대한전자공학회 2004 電子工學會論文誌-TC (Telecommunications) Vol.41 No.12

본 논문에서는 마이크로스트립 전송선로에 주기적으로 계단형 스터브를 부가하여 물리적 길이를 소형화시킨 마이크로스트립 전송선로를 나타내었다. 주기적인 계단형 스터브는 quasi-static analysis와 전송선 이론을 바탕으로 한 등가모델로 병렬로 부가된 커패시턴스 역할을 함을 보였으며, 기존의 일반 스터브를 이용한 경우보다 짧은 길이의 스터브로 높은 커패시턴스 부가 효과를 얻을 수 있음을 보였다. 그리고 이러한 선로를 이용하여 소형화된 branch-line 결합기와 rat-race결합기를 설계하였다. 1.8 ㎓에서 구현된 각각의 결합기는 677 ㎟, 913 ㎟으로 일반적인 결합기에 비해 그 크기가 62%, 45%로 다른 소자의 부가 없이 단지 전송선로의 변형만을 통해 매우 효과적으로 축소되었다. In this paper, we introduce the advanced compact transmission line with periodic stepped stubs. They are more effective than normal stubs in ATL. The short stepped stubs loading of transmission line work as effective shunt capacitance and that was proved by equivalent circuit based on transmission line theory and quasi-static analysis. And the compact branch-line coupler and the compact rat-race coupler via proposed compact microstrip line were designed at 1.8 ㎓. They have 677 ㎟ and 913 ㎟, respectively, and they are 62% and 45% of normal design.

재순환류가 존재하는 난류확산화염에 관한 연구

이창언(Chang-Eon Lee),오수철(Su-Cheol Ohu) 한국항공우주학회 1994 韓國航空宇宙學會誌 Vol.22 No.5

[일반논문] 한국학생운동의 연구 경향과 과제에 관한 연구 - 연구방법론을 중심으로 -

이창언(Lee Chang-Eon) 역사학연구소 2005 역사연구 Vol.- No.15

가스호환성 판정에 편리한 화염안정영역의 새로운 좌표계의 제안 및 유용성 검토

이창언(Chang-Eon Lee),황철홍(Cheol-Hong Hwang),홍성창(Sung-Chang Hong),김종민(Jong-Min Kim) 한국가스학회 2008 한국가스학회 학술대회논문집 Vol.2008 No.4

동해안지역 반촌 역사ㆍ문화자원의 문화관광 자원화 방안

이창언(Lee Chang-un) 역사문화학회 2007 지방사와 지방문화 Vol.10 No.1

본 논문의 목적은 동해안 지역에서는 드물게 반촌이 밀집된 경상북도 영덕군 영해지역의 역사와 문화적 특성을 문화관광의 자원으로 활용하는 방안을 모색하는 것이다. 영해지역에는 이미 유교문화권 개발사업을 통해서 반촌에 대한 정비사업이 상당히 진척되었다. 이 지역의 역사와 문화의 특성을 반영한 프로그램을 복원 정비된 반촌에서 진행할 때, 문화자원의 보존과 활용의 효과를 기대할 수 있다. 영해지역의 역사ㆍ문화적 특성은 학업과 의를 숭상한 선비정신과 반가의 의례 및 생활문화로 대표된다. 퇴계학맥을 계승한 영해지역의 높은 학문적 전통과, 국난 시 구국활동의 전면에 나선 선비정신의 실천은 현재까지도 반가의 의례와 향례를 통해서 이어지고 있다. 또한 반가의 의례용 음식과 가양주는 훌륭한 음식문화의 자원으로 활용될 수 있다. 이처럼 역사적, 문화적, 교육적, 실용적 가치가 높은 영해지역의 역사ㆍ문화자원을 응용한 문화체험프로그램을 운용할 때, 영해지역의 역사와 문화의 전승은 물론 관광산업에 미치는 효과가 클 것으로 기대된다. This study is concerning culture tourism of banchon in East coast area. The research field is the Yeonghae area where many banchons are scattered. Banchon is the lineage village where most residents are composed of the aristocratic class of Korean traditional society, which is called yangban. There are a lot of cultural assets which are related with Confucianism culture in banchon of Yeonghae area. Recently, culture tourism becomes the center of public interest in Korean society. A number of Confucian cultural assets especially in the northern Gyeongbuk area are being restored for preservation of cultural assets and culture tourism by the Korean government. However, efforts and concerns for culture tourism are mostly concentrated on the restoration works of tangible Confucian cultural assets such as old houses, shrines, and bowers. Some programs for experience of Confucianism cultur, are, hence, necessary for proper culture tourism. Principles for proper culture tourism are authenticity, possibility of realization and durability. On the basis of these principles, we expect both proper Confucianism culture experience programs unique in history and culture of the local area. Characteristics of Confucianism culture in the Yeonghae area are both academic attainments of Confucian scholars who succeed the Yeongnam Confucianism tradition and the attitude of scholars who devoted themselves to the national salvation when foreigners invaded. These characteristics of Confucianism culture in the Yeonghae area have been maintained in the following two aspects: (1) the rituals such as ancestor worships and the rituals held by community: and (2) food culture. including food for ritual. wine and the seasonal food made by noble families. Some requisites to develop adequate programs are as follows. First, a detailed ethnographic work about the history and culture of banchon should be carried out. Second, the programs suitable for the characteristics of those people who would participate in the program should be developed. Third, an organization composed of residents, experts in history and culture and officials worked for the local government should be established for management and support of the program. Finally, we are able to expect a desirable result by connecting the culture programs and other programs specialized in Buddhism culture and folk culture.