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희박 예혼합 덤프 연소기에서 OH 자발광을 이용한 열 방출에 관한 실험적 연구
문건필(Gun Feel Moon),이종호(Jong Ho Lee),전충환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Measurements of OH chemiluminescence in an atmospheric pressure, laboratory-scale dump combustor at equivalence ratios ranging from 0.63 to 0.89 were reported. The signal from the first electronically excited state of OH to ground state was detected through a band-pass filter with an ICCD. The objectives of this study are two: One is to see the effects of equivalence ratio on global heat release rate and local Rayleigh index distribution. To get the local Rayleigh index distribution, the line-of-sight images were inverted by tomographic method, such as Abel de-convolution. Another aim is to investigate the validity of using OH chemiluminescence acquired with an ICCD as a qualitative measure of local heat release. For constant inlet velocity and temperature, the overall intensities of OH emission acquired at different equivalence ratio showed periodic and higher value at high equivalence ratio. OH intensity averaged over one period of pressure increased exponentially with equivalence ratio. Local Rayleigh index distribution clearly showed the region of amplifying or damping the combustion instability as equivalence ratio increased. It could provide an information/insights on active control such as secondary fuel injection. Finally, local heat release rate derived from reconstructed OH images were presented for typical locations.
희박 예혼합 모형 가스터빈 연소기의 화염구조와 배기특성에 관한 실험적 연구
문건필(Gun Feel Moon),이종호(Jong Ho Lee),전층환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
The objective of this study is a qualitative comparison between line-integrated OH chemiluminescence<br/> (OH*) image and its Abel inversion image at different phase of the oscillating pressure field.<br/> PIV(Particle Image Velocimetry) measurements were conducted under non-reacting conditions to see<br/> the global flow structure. Also NOx emission was measured to investigate the effect of fuel-air<br/> premixing on combustion instability and emission characteristics. Experiments were carried out in an<br/> atmospheric pressure, laboratory-scale dump combustor operating on natural gas. Combustion instabilities<br/> in present study exhibited a longitudinal mode with a dominant frequency of ~341.8 Hz, which<br/> corresponded to a quarter wave mode of combustor. Heat release and pressure waves were in-phase<br/> when instability occurred.<br/> Results gave an insight about the location where the strong coherence of pressure and heat release<br/> existed. Also an additional information on active control to suppress the combustion instabilities was<br/> obtained. For lean premixed combustion, strong correlation between OH* and NOx emissions was<br/> expected largely due to the exponential dependence of thermal NOx mechanism on flame temperature.
2차원 시분해 레이저 유도 백열법을 이용한 에틸렌 확산 화염에서의 매연 입자 크기 측정
손무강(Moo Kang Shon),문건필(Gun Feel Moon),김규보(Gyu Bo Kim),이종호(Jong Ho Lee),정동수(Dong Soo Jeong),전충환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Laser-induced incandescence (LII) is introduced as a valuable tool for the characterization of nanoparticles in flame environments. This technique is based on the heating of the particles by a short laser pulse and the subsequent detection of the thermal radiation. It has been applied successfully for the investigation of soot in different fields of application. The evaluation of the temporal decay of the laser-induced incandescence (LII) signal from soot particles is introduced as a technique to obtain two-dimensional distributions of particle sizes and is applied to a laminar diffusion flame. This novel approach to soot sizing exhibits several theoretical and technical advantages compared with the established combination of elastic scattering and LII, especially as it yields absolute sizes of primary particles without requiring calibration. With this technique a spatially resolved 2-D measurement of soot primary particle sizes is feasible in a combination process form the ratio of emission signals obtained at two delay times after a laser pulse, as the cooling behavior is characteristic of particle size.