메탄/공기 층류 부분예혼합화염의 상세 라디칼(OH*, CH* 그리고 C₂*) 정보와 배기매출물에 관한 실험적 연구

정용기,오정석,전충환,장영준,Jeong Yong Ki,Oh Jeong Seog,Jeon Chung Hwan,Chang Young June 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.2

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $0.79{\sim}{\infty}$, on NOx emissions and chemiluminescence of excited $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ radicals in laminar partially premixed flames. the signal from the electronically excited state of $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, which are processed to the intensity ratio ($C_2^{\ast}/CH^{\ast},\;C_2^{\ast}/OH^{\ast},\;and\;CH^{\ast}/OH^{\ast}$) to reveal the correlation with local equivalence ratio. And measurements of NOx emission were made to investigate the relationship between visible flame appearance, chemiluminescence, and EINOX. The results demonstrated that (1) the flames at ${\phi}<1.59$ exhibited classical double flame structure, at ${\phi}>4.76$, the flames exhibited diffusion flame structure, and the intermediate flames at $1.59<{\phi}<4.76$ was a merged flame, (2) the $OH^{\ast}$ peak was located inside the $CH^{\ast}\;and\;C_2^{\ast}$ radical for all measured conditions and the emission intensity ratio of $C_2^{\ast}/CH^{\ast}\;and\;C_2^{\ast}/OH^{\ast}$ were identified as good marker for local equivalence ratio over a range of ${\phi}=0.79{\sim}1.2\;and\;CH^{\ast}/OH^{\ast}\;is\;0.79<{\phi}<1.9$. However, it was difficult to predict the equivalence ratio in partially premixed flames using this system for ${\phi}>2.38$, (3) the minimum NOX emission index (EINOx) is obtained for a equivalence ratio of 3.19 in the intermediate flames.

메탄 공기 층류 부분 예혼합화염에서 예혼합 정도에 따른 화염구조와 질소산화물의 배출에 미치는 영향에 관한 연구

오정석(Jeong Seog Oh),정용기(Yong Ki Jeong),전층환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11

It is shown that the effect of variable parameters on flame structures and NOx emissions in the laminar<br/> partially premixed methane-air flames with a co-axial Bunsen burner. Objectives of this paper is to<br/> understand the effects of flow variables on NOx emissions and the flame structure with OH<br/> chemiluminescence, including reconstructed image by abel inversion processing at each conditions. A fuel<br/> flowrate of 200 [cc/min] was fixed and the amount of air was varied from 400 to 1200 [cc/min]. The<br/> experimental variables were equivalence ratio( ), fuel split percentage( ) and inner tube recess(x/D). Flow<br/> conditions were ranged from 1.36~4.76(equivalence ratio), 50~100(fuel split percentage) and 0~20(inner<br/> tube recess). NOx analyzer and ICCD camera with a OH filter were used as a main experimental<br/> apparatus. In addition, Abel inversion, which is a kind of tomography and valuable to estimate a<br/> two-dimensional structure of co-axial flames from cubical information, was employed for combustion<br/> diagnostics. Results from this study indicate that the main effects depend on equivalence ratio and next<br/> sigma, x/D for NOx production and OH formation. Throughout Abel inversion, we could affirm the<br/> maximum position and the tendency of OH radical intensity by variants at five axial heights above the<br/> burner exit.

이중동축 메탄/공기 층류 부분 예혼합화염에서의 화염구조와 자발광 배출 특성 안쪽관 연료주입의 영향

오정석(Jeong Seog Oh),정용기(Yong Ki Jeong),전충환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11

In this study, the effect of central fuel injection on a coaxial laminar CH₄/air flame was experimented at the defined premixing condition(φ=1.90, σ=50/75/100%, x/D=10). The partial premixing parameter are the equivalence ratio that total fuel is fixed at 200cc/min, the fuel split degree which means the percentage of fuel entering the outer tube to the total amount, and the mixing distance indicating the nonreactant mixture's homogeneity between inner tube top and burner exit. The object is to investigate the flame structure and chemiluminescence characteristics of laminar partial premixed flame as changing mixing parameters. The radical signal was acquired from ICCD camera and PMT. Each intensity was compared with Abel inverted value for measuring the effect of background light on the peak signal location and the intensity at central preheat zone. The results show that the peak location of each radical was broaden as the fuel split degree increasing because the mixing quality was enhanced. and OH* is a good indicator for flame front between reaction and preheat zone. At last C₂* has the same tendency with CH* but a thinner reaction zone than CH* due to a rapid decay on the burned gas side.

합성하수를 이용한 금속 막의 정밀여과 특성 및 막 오염 제어

정종태,김종오,김학균,김석구,이용재 7개 국립대학교 환경연구 논문집 공동발행 위원회 2004 공업기술연구 Vol.4 No.-

This study was to evaluate the filtration performance of metal membrane with synthetic wastewater and to investigate the effective control of membrane fouling using ozone backwashing. The increase of substrate concentration caused the increase of cake layer resistance and total resistance, however, plugging resistance decreased. Total resistance of metal membrane was mainly attributed to the permeate resistance of cake layer, which was formed by deposited particles from the physico-chemical interactions of solids on membrane surface. Intermittent ozone backwashing was more effective then the air backwashing for fouling reduction. The permeation flux recovery of air backwashing decreased over 50%, however, ozone backwashing decreased less than 10% for 4 hours filtration. This may be ascribed to the degradation of foulants in pore structure by the strong oxidation of ozone and physical exfoliation of cake layer on membrane surface with backwashing.

OPTIMIZATION OF UNSUPPORTED CO-MO CATALYSTS FOR DECARBOXYLATION OF OLEIC ACID

Jae-Oh SHIM,Dae-Woon JEONG,Won-Jun JANG,Kyung-Won JEON,Hyun-Seog ROH,Jeong-Geol NA,You-Kwan OH,Sang Sup HAN,Chang Hyun KO 한국신재생에너지학회 2013 AFORE Vol.2013 No.-

Is step section necessary for determination of complete pathological response in rectal cancer patients treated with preoperative chemoradiotherapy?

Park, Seog Yun,Chang, Hee Jin,Kim, Dae Yong,Jung, Kyung Hae,Kim, Sun Young,Park, Ji Won,Oh, Jae Hwan,Lim, Seok‐,Byung,Choi, Hyo Seong,Jeong, Seung‐,Yong Blackwell Publishing Ltd 2011 Histopathology Vol.59 No.4

<P>Park S Y, Chang H J, Kim D Y, Jung K H, Kim S Y, Park J W, Oh J H, Lim S‐B, Choi H S & Jeong S‐Y
(2011) <I>Histopathology</I><B>59</B>, 650–659</P><P><B>Is step section necessary for determination of complete pathological response in rectal cancer patients treated with preoperative chemoradiotherapy?</B></P><P><B>Aims: </B> To assess the efficacy of the step section for determination of pathological complete response (pCR) in rectal cancer treated with preoperative chemoradiotherapy (CRT).</P><P><B>Methods and results: </B> Of 709 patients with rectal cancer who received preoperative CRT, 88 were initially diagnosed as having pCR. These 88 patients were re‐evaluated after two‐level step sections of the entire tumour by using Dworak’s regression grade. Additional serial step sections revealed residual tumour cells in seven of 88 patients (7.95%), all of whom were upgraded to regression grade 3 (near total regression) from regression grade 4 (total regression). Of these seven patients, one (14.3%) showed tumour recurrence, compared with 11 of 81 (13.6%) patients with a final regression grade of 4. Neither recurrence rate nor disease‐free survival rate differed significantly between these two groups (<I>P </I>><I> </I>0.5). Calcification was significantly more frequent in grade 3 than in grade four patients (71.4% versus 32.1%; <I>P </I>=<I> </I>0.037), and acellular mucin pools were associated with better disease‐free survival (<I>P </I>=<I> </I>0.022).</P><P><B>Conclusions: </B> Stratifying patient outcome by final regression grade after step section did not yield different outcomes in patients with initial pCR. If residual tumour cells are not identified on initial meticulous examination, further processing of step sections is not necessary.</P>

부상된 동축공기 수소 난류확산화염에서의 화염안정화 특성

오정석(Jeong-Seog Oh),김문기(Mun-ki Kim),윤영빈(Young-bin Yoon) 한국항공우주학회 2008 한국항공우주학회지 Vol.36 No.4

수소제트와 동축공기를 사용한 본 연구에서, 난류확산화염의 화염안정성 특정을 실험적으로 수행하였다. 목적은 연료속도 증가에 따라 감소하는 부상화염길이의 경향을 보고하고, 부상 메커니즘을 포함한 화염구조를 분석하는 것이다. 수소연료는 100에서 300 ㎧ 사이에서 조절되었으며, 이때 동축공기는 16 ㎧ 고정되고, 주위류는 0.1 ㎧ 이하로 유지되었다. 유동장과 연소장 동시측정을 위하여, 두 대의 Nd:Yag 레이저와 CCD 카메라를 이용하여 PIV와 OH PLIF 기법이 사용되었다. 결론적으로 난류화염전파속도는 난류강도에 비례하였으며, 제트 레이놀즈수의 0.017승에 비례하였다. In this study of lifted hydrogen jet with coaxial air, we have experimentally studied the characteristics of stabilization point in turbulent diffusion flames. The objectives are to present the phenomenon of a liftoff height decreasing as increasing fuel velocity and to analyse the flame structure and behavior including liftoff mechanisms. The fuel jet exit velocity was changed from 100 up to 300 ㎧ and a coaxial air velocity was fixed at 16 ㎧ with a coflow air less than 0.1 ㎧. For the simultaneous measurement of velocity field and reaction zone, PIV and OH PLIF technique was used with two Nd:Yag lasers and CCD cameras. It has been suggested that the stabilization of lifted hydrogen diffusion flames was correlated with a turbulent intensity, S<SUB>t</SUB>~u′, and jet Reynolds number, S<SUB>t</SUB>~Re<SUB>jet</SUB><SUP>0.017</SUP>.

보일러 열에너지 이용 및 시스템 효율 향상을 위한 습식 분무 응축 열교환 개념 적용 가능성 연구

오정석(Jeong-Seog Oh),강새별(Sae-Byul Kang),이현희(Hyun-Hee Lee),최규성(Kyu-Sung Choi) 대한기계학회 2019 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.7 No.2

대표적인 에너지 다소비기기인 보일러 시스템에 습식분무 응축열교환 개념을 적용하여 열에너지 이용효율 향상 및 온실가스배출 저감 가능성을 실험적으로 연구하였다. 실험장치로 약 10만 ㎉-H₂O/hr급 온수 보일러를 사용하였으며 배기가스 후단에 직경 약 0.5 ㎜의 중공 원뿔형 물 분사 시스템을 설치하였다. 물 분사량과 배기가스 배출조건을 고정한 상태에서 배기관 단열 유무, 배기가스 온도, 응축열교환기 냉각유량에 따른 응축수량을 측정하였다. 실험결과 응축 시작온도가 배기관 단열전에는 약 80 ℃였으나 배기관 단열시 약 60 ℃로 낮아졌다. 배기가스로 물을 분사할 경우 응축수량이 증가하였으며 배가스 온도도 감소하였다. 배기가스 온도를 낮추거나 응축열교환기의 냉각 수량을 증가할 경우 응축수량 역시 증가하였다. The concept of condensing heat exchange with water spray (CHEWS) into a flue gas was experimentally investigated to confirm the possibility of application to conventional boiler system. An 100,000 ㎉ scale hot-water boiler was used and installed with a hollow-cone type water spray system in the current study. As a experimental results, the gas-phase water began to be condensed about 60 ℃ in case of vent pipe insulation. The amount of condensed water increased with a decrease in flue gas temperature while decreased with a decrease in cooling water in a heat exchanger.

메탄/공기 층류 부분 예혼합화염의 화염구조와 NOx 배출특성

오정석(Jeong Seog Oh),정용기(Yong Ki Jeong),전충환(Chung Hwan Jeon),장영준(Young June Chang) 한국연소학회 2003 KOSCOSYMPOSIUM논문집 Vol.- No.-

Hydrodeoxygenation of oleic acid over Ce<SUB>(1-x)</SUB>Zr<SUB>(x)</SUB>O<SUB>2</SUB> solid solution

Jae-Oh Shim,Dae-Woon Jeong,Won-Jun Jang,Kyung-Won Jeon,Won-Bi Han,Hyun-Suk Na,Hak-Min Kim,Hyun-Seog Roh,Jeong-Geol Na,You-Kwan Oh,Chang Hyun Ko,Sang Sub Han 한국신재생에너지학회 2013 한국신재생에너지학회 학술대회논문집 Vol.2013 No.05