http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
수소/이산화탄소/알곤 혼합 연료의 비예혼합 대향류 화염에서 NO 배출 특성 연구
이기만,Lee, Kee-Man 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.4
The detailed chemistry with reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions, have been numerically conducted to investigate the flame structure and NO emission characteristics in a non-premixed counterflow flame of blended fuel of $H_2/CO_2/Ar$. The combination of $H_2,\;CO_2$, and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of $CO_2$. Radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. All mechanisms including thermal, $NO_2,\;N_2O$, and Fenimore are also taken into account to separately evaluate the effects of $CO_2$ addition on NO emission characteristics. The increase of added $CO_2$ quantity causes flame temperature to fall since at high strain rates diluent effect is prevailing and at low strain rates the breakdown of $CO_2$ produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the ratio of the contribution by Fenimore mechanism to that by thermal mechanism in the total mole production rate becomes much larger with increase in the $CO_2$ quantity and strain rate, even though the absolute quantity of NO production is deceased. Consequently, as strain rate and $CO_2$ quantity increase, NO production by Fenimore mechanism is remarkably augmented.
횡분류(流)(橫噴流)에서 난류 비예흔합 화염의 화염날림에 대한 거대 와(渦)구조 혼합 모텔 적용
이기만,박정,Lee, Kee-Man,Park, Jeong 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.1
This article presents an application of a large-scale structural mixing model(Broadwell et at. 1984) to the blowout of turbulent reacting cross flow jets. Experimental observations, therefore, aim to identify the existence of large-scale vortical structure exerting an important effect upon the flame stabilization. In the analysis of common stability curve, it is seen that the phenomenon of blowout are only related to the mixing time scale of the two flows. The most notable observation is that the blowout distance is traced at a fixed positions according to the velocity ratio at all times. Measurements of the lower blowout limits in the liftable flame are qualitatively in agreement with the blowout parameter $\xi$, proposed by Broadwell et al. Good agrement between the results calculated by a modified blowout parameter $\xi$'and the present experimental results confirms the important effect of large-scale structure in the stabilization feature of blowout.
음향 가진된 층류 비예혼합 분류 화염에서 거대 와류 거동에 관한 가시화 연구
이기만,오세기,박정,Lee, Kee-Man,Oh, Sai-Kee,Park, Jeong 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.3
A visualization study on the effect of forcing amplitude in tone-excited jet diffusion flames has been conducted. Visualization techniques are employed using optical schemes. which are a light scattering photography. Flame stability curve is attained according to Reynolds number and forcing amplitude at a fuel tube resonant frequency. Flame behavior is globally grouped into two from attached flame to blown-out flame according to forcing amplitude: one sticks the tradition flame behavior which has been observed in general jet diffusion flames and the other shows a variety of flame modes such as the flame of a feeble forcing amplitude where traditionally well-organized vortex motion evolves, a fat flame. an elongated flame. and an in-burning flame. Particular attention is focused on an elongation flame. which is associated with a turnabout phenomenon of vortex motion and on a reversal of the direction of vortex roll-up. It is found that the flame length with forcing amplitude is the direct outcome of the evolution process of the formed inner flow structure. Especially the negative part of the acoustic cycle under the influence of a strong negative pressure gradient causes the shapes of the fuel stem and fuel branch part and even the direction of vortex roll-up to dramatically change.
주유동에 수직으로 분사되는 난류 비예혼합 분류 화염의 특성
이기만,박정,Lee, Kee-Man,Park, Jeong 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.1
An experimental study on the characteristics of stability of propane turbulent nonpremixed jet flames discharged normal to air free-streams with uniform velocity profile is conducted. Experimental observations are focused on the flame shape, the stability considering two kinds of flame, lift-off distance, and the flame length according to velocity ratio. In order to investigate the mixing structure of the flame base at the lower limit, we employ the RMS technique and measure the species concentration by a gas chromatography. In the results of the stability curve and lifted flame, it is fecund that the dependency of nozzle diameter is closely related to the large-scale vortical structure representing counter-rotating vortices pair. Also, the detailed discussion on the phenomenon of blowout due to this large vortical motion, is provided.
수소-산소 대향류 확산 화염에서 산화제와 연료측에 첨가된 Co<sub>2</sub>의 화학적 효과에 관한 수치해석 연구
이기만,박정,Lee, Kee-Man,Park, Jeong 대한기계학회 2004 大韓機械學會論文集B Vol.28 No.4
Numerical simulation of $CO_2$ addition effects to fuel and oxidizer streams on flame structure has been conducted with detailed chemistry in H$_2$-O$_2$ diffusion flames of a counterflow configuration. An artificial species, which displaces added $CO_2$ in the fuel- and oxidizer-sides and has the same thermochemical, transport, and radiation properties to that of added $CO_2$, is introduced to extract pure chemical effects in flame structure. Chemical effects due to thermal dissociation of added $CO_2$ causes the reduction flame temperature in addition to some thermal effects. The reason why flame temperature due to chemical effects is larger in cases of $CO_2$ addition to oxidizer stream is well explained though a defined characteristic strain rate. The produced CO is responsible for the reaction, $CO_2$+H=CO+OH and takes its origin from chemical effects due to thermal dissociation. It is also found that the behavior of produced CO mole fraction is closely related to added $CO_2$ mole fraction, maximum H mole fraction and its position, and maximum flame temperature and its position.