• Title/Summary/Keyword: 평면형광기법

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A Planar Imaging System for Spray Patternation (분무 패턴 측정을 위한 평면 이미지 기법)

  • 이경진;정기훈;윤영빈;정경석;정인석
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1998.10a
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    • pp.7-7
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    • 1998
  • 액체 연료 분포의 균일성과 대칭성은 연소 효율을 높이고, 공해 물질을 줄이는데 있어서 필수적인 요소이기 때문에 분무 패턴을 정량적으로 해석하는 것은 매우 중요하다. 고전적으로 사용되고 있는 mechanical patternator는 ⅰ) 유동을 교란시키고, ⅱ) 공간 분해능이 떨어지며, ⅲ) 복잡한 재순환 유동이나 화학 반응이 있는 유동에서의 적용이 어렵다는 단점을 가지고 있다. 이러한 단점들을 극복하기 위하여 레이저를 이용한 optical patternator에 대한 연구가 진행되고 있다. Optical patternator는 유동을 교란시키지 않으면서 고해상도의 분무 패턴 측정을 할 수 있다. 형광 신호는 물질의 체적에 비례한다. 따라서, 레이저 평면광을 분무에 조사시켜 주어서 유도되는 형광 신호를 이용하는 평면액체 레이저 유도 형광법(PLLIF : Planar Liquid Laser Induced Fluorescence)은 분무패턴을 알아보는 매우 유용한 방법이다.

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Measurement of the fuel distribution in a scaled ATR combustor using PLIF (PLIF를 이용한 ATR 연소기 축소모형의 연료분포 측정연구)

  • Jin Yu-In;Yang In-Young;Choi Young-Hwan;Yang Soo-Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.4
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    • pp.55-65
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    • 2005
  • Mixing performance between fuel and oxidizer is a significant parameter of combustion efficiency and stability in an air-turbo ramjet combustor. Two types of petal mixer were experimented to research the mixing performance. Mixing performance and fuel distribution images were obtained for petal mixers. Planar laser-induced fluorescence(PLIF) was used to obtain 2-D fuel distribution. The obtained images were processed in order to make use of the image information to a quantitative level. The results of analyzing the fluorescence images could be useful to find better mixing performance between mixers.

Fuel Distribution Measurements in ATR Combustor using PLIF (PLIF를 이용한 ATR 연소기 내부의 연료분포 측정)

  • Yang In-Young;Jin You-In;Yang Soo-Seok;Park Seung-Jae
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.274-277
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    • 2004
  • Fuel/air mixing in air turbo ramjet(ATR) combustor is a significant parameter of combustion stability and efficiency. In this study, fuel distribution in the ATR model combustor was measured to compare the degree of mixing with respect to the velocity ratio$(r=v_a/v_f)$ between fuel gas and air. Planar laser-induced fluorescence(PLIF) and image processing method were used to obtain two dimensional fuel distribution. Fuel mixing went bad with approaching to r=1.

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An Experimental Investigation of Air Fuel Ratio Measurement using Laser Induced Acetone Fluorescence (아세톤 형광을 이용한 공연비 측정 기법 연구)

  • Park Seungjae;Huh Hwanil;Oh Seungmook
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.353-356
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    • 2002
  • Planar laser induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Preliminary investigation was performed to measure quantitative air excess ratio distribution in an engine fueled with LPG. It is known that fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone was excited by KrF excimer laser (248nm) and its fluorescence image was acquired by ICCD camera with a cut-of filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile was suggested. Raw images were divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which was taken by a calibration process, were converted to air excess ratio distribution. This investigation showed instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

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A study on Visualization and Enhancement the Latent Fingerprints on Multi-colored Surfaces using the Forensic Light Sources (법광원을 이용한 복잡한 배경의 잠재지문 시각화 및 증강에 관한 연구)

  • Cho, Hyeong-Woo;Koh, Hyun-Seo;Han, Sang-Gyoun;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.16 no.3
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    • pp.72-80
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    • 2016
  • There are various methods of developing latent fingerprints from evidence found at crime scenes. Crime scene investigators should choose appropriate techniques among them depending on the conditions of the evidences. In this study, we compared the three methods using forensic light sources to develop latent fingerprints on multi-colored surfaces. We selected the various samples according to color, shape and texture of the surfaces and developed the latent fingerprints using fluorescent powder, IR(Infrared) photography and Episcopic Co-axial Illumination. Fluorescent powder was highly effective on all surfaces. IR photography was also effective, but only on the not dark surfaces. Episcopic Co-axial Illumination was effective only on the flat and polished surfaces. Although fluorescent powder was fine regardless of the characteristics of the surfaces, IR photography was better on certain surfaces.

Analysis of the Spray Distribution Characterization of Impinging Jet Injectors for Liquid Rockets Using PLIF Technique (PLIF 기법을 이용한 액체로켓용 충돌분사 인젝터의 분무분포 특성 해석)

  • 정기훈;윤영빈;황상순
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.1
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    • pp.36-45
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    • 2000
  • Most researches for impinging jet spray have been focused on under-standing the breakup mechanism of a liquid sheet formed by the collision of jets and modeling the spray breakup using experimental data. For this reason, there have been few studies on the characteristics of the spatial spray distribution which affects significantly the combustion efficiency. Hence, we measured the radial distribution of fuel massflux using a like-doublet type injector. Instead of PDPA(Phase Doppler Particle Analyzer) which has been used only for the point measurement of the drop size of spray, PLIF(Planar Laser Induced Fluorescence) technique was developed lot the 2-D measurement of the massflux distribution of spray Indirect photography technique was also used to verify PLIF data.

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An Experimental Study on the Trajectory Characteristics of Liquid Jet with Canted Injection Angles in Crossflow (수직분사제트에서 다양한 분사각도의 분무궤적 특성에 대한 실험적 연구)

  • Kim, Min-Ki;Song, Jin-Kwan;Hwang, Jeong-Jae;Yoon, Young-Bin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.6
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    • pp.38-47
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    • 2008
  • The liquid column and spray trajectory have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle were varied to provide of jet operation conditions. The Pulsed Shadowgraph Photography and Planar Liquid Laser Induced Fluorescence technique was used to determine the injection characteristics in a subsonic crossflow of air. And the mainly objectives of this research was to get a empirical formula of liquid column and spray region trajectory with forward and reversed injection of air stream. As the result, This research has been shown that each trajectories were spatially dependent on air-stream velocity, fuel injection velocity, various injection angle, and normalized injector exit diameter. Furthermore, the empirical formula of liquid column trajectories has been some different of drag coefficient results between forward and reversed angled injection.

A Study on the baffle effect in a stirred mixer using simultaneous measurement of velocity/concentration fields (속도/농도 동시측정에 의한 회전교반기 내부 유동의 baffle 효과에 관한 연구)

  • Kim Yun Gi;Min Young Uk;Kim Kyung Chun
    • 한국가시화정보학회:학술대회논문집
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    • 2003.11a
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    • pp.35-38
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    • 2003
  • Simultaneous measurement of velocity and concentration fields in a stirred mixer flow using a combined Stereo-PIV/Planar-LIF technique is carried out. Instantaneous velocity fields and concentration fields represent the local flow characteristics. A baffle is perpendicularly attached to the Wall to remove inactive region which shows very slow dispersion. It is found that the baffle produces tip vortex and breaking the divided streamline, so that mixing efficiency could be increases significantly.

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Study on the Fuel Vapor Distribution of the Stratified Charge in a DISI Engine by PLIF Technique (직분식 전기점화 엔진에서 PLIF기법에 의한 성층 혼합기의 분포특성 연구)

  • Kim, S.S.
    • Journal of Power System Engineering
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    • v.12 no.6
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    • pp.64-69
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    • 2008
  • The spatial fuel distribution of the stratified charge of a high pressure 6-hole injector was examined in a single cylinder optical direct injection spark ignition(DISI) engine. The effects of in-cylinder charge motion, and fuel injection pressure, and coolant temperature were investigated using a planar LIF(Laser Induced Fluorescence) technique. It was confirmed that the in-cylinder tumble flow played more effective role in the spatial fuel distribution of the stratified charge than the swirl flow during the compression stroke and the fuel distribution area increased due to the activation of the fuel vaporization by the increase of the coolant temperature. But, the increase of the fuel supplying pressure could not change the pattern of the fuel vapor distribution against the expectation.

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The Comparison of Spray Characteristics between FOOF and FOF Injectors used in Liquid Rockets (액체로켓용 FOOF와 FOF 인젝터의 분무특성 비교)

  • 임병직;정기훈;윤영빈
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.2
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    • pp.1-6
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    • 2003
  • Triplet(FOF or OFO) injectors are commonly applied to liquid rockets which use LOX and hydrocarbon propellants. The FOF type injector has been known to have an advantage for the although to show lower combustion performance as compared by the OFO type. However, a large disparity between oxidizer and fuel orifice diameters of the FOF type injector may reduce both the combustion efficiency and stability so that as FOOF split triplet injector which splits a single oxidizer orifice into double orifices was designed. In the present study, spray characteristics of the FOOF injector were investigated and compared with those of the FOF injector undo. cold flow conditions. Mass distributions of oxidizer and fuel for both injectors were measured by using a PLLIF (Planar Liquid Laser Induced Fluorescence)technique, and each drop size was also measured by using an instantaneous photographic method. From the experimental results, we found out that FOOF shows more stable mixing efficiencies than the FOF. As for the drop size of both oxidizer and fuel, there was not a large difference between two injector types.