• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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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.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1808-1815
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• 2001

The characteristics of a pulsed plasma jet originating from an electrothermal capillary discharge have been investigate using laser-induced fluorescence (LIF) measurement. Previous emission measurements of a 3.1 kJ plasma jet show trial upstream of the Mach disk the temperature and electron number density are about 14,000 K and and 10$\^$17/ cm$\^$-3/, while downstream of the Mach dick tole values are about 25,000 K and 10$\^$18/ cm$\^$-3/, respectively. However, these values are barred on line-of-sight integrated measurements that may be misleading. Hence, LIF is being used to provide both spatially and temporally resolved measurements. Our recent work has been directed at using planar laser-induced fluorescence (PLIF) imaging of atomic copper in the plasma jet flow field. Copper is a good candidate for PLIF studies because it is present throughout the plasma and has electronic transitions that provide an excellent pump-detect strategy. Our PLIF results to date show that emission measurements may give a misleading picture of the flow field, as there appeals to be a large amount of relatively low temperature copper outside the barrel shock. which may lead to errors in temperature inferred from emission spectroscopy. In this paper, the copper LIF image is presented and at the moment, relative density of atomic copper, which is distributed in the upstream of the pulsed plasma jet, is discussed qualitatively.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.74-82
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• 2004

Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-off 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 is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

• 한국연소학회지
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• 제15권4호
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• pp.43-52
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• 2010

A non-intrusive measurement, Planar Laser Induced Fluorescence was employed to visualize and measure the fuel distribution of the non-reacting field at the burner exit of gas turbine combustor. Measurement techniques, image processing method and quantification procedure were presented. Also, concentration measurement with gas analyzer was carried out to verify the propriety of PLIF result. The PLIF result coincides well with gas analyzer measurement result. PLIF test result for several other conditions are mentioned as well.

• 동력기계공학회지
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• 제12권6호
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.694-699
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• 2003

Simultaneous measurement with PLIF(Planar Laser-Induced Fluorescence) and Stereo-PIV(Stereoscopic Particle Image Velocimetry) was performed to investigate the structural characteristics of flow field in Rushton Turbine Mixer. Instantaneous 3D velocity fields are measured by two 2K ${\times}$ 2K CCD cameras focused on an object plane with the angular displacement methods while the concentration fields are obtained through the measurement of the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. Finally, the spatial structures of turbulent mixing around Rushton turbine were identified by the calculation of cross-correlation fields between the velocity and concentration field.

• Journal of Advanced Marine Engineering and Technology
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• 제27권2호
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• pp.260-271
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• 2003

For the Purpose of understanding the mixing phenomena of a GDI(Gasoline Direct Injection) engine, the spray behaviors and fuel distributions were investigated in a single cylinder transparent GDI engine. The experimental engine is a swirl type GDI engine with a SCV(Swirl Control Valve). PLIF(Planar Laser Induced Fluorescence) system with KrF Excimer laser was used for the measurement of the fuel distributions. The effects of SCV opening angles and the injector specifications on the fuel distribution characteristics were investigated. As a result, it was found that the SCV opening angle had a great effect on the fuel distributions in the late stage of compression process by changing the flow fields in the combustion chamber.

• 한국추진공학회지
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• 제4권1호
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• pp.36-45
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• 2000

지금까지의 충돌분무에 대한 연구는 제트의 충돌시 형성되는 액막의 분열 과정을 이해하고 이를 모델링하는데 초점을 두어왔기 때문에 실질적으로 연소 효율에 가장 큰 영향을 미치는 연료의 공간분포 특성에 대한 연구가 부족하였다. 따라서 본 연구에서는 like-doublet 충돌분사 노즐을 사용하여 연료 유량 플럭스의 단면분포 특성을 연구하였다. PDPA(Phase Doppler Particle Analyzer)를 통해 액적의 크기를 측정한 기존의 방법은 연료의 평면적인 분포특성을 이해하는데 상당히 제한적이었기 때문에 평면 레이저 유도형광기법(PLE : Planar Laser Induced Fluorescence)을 이용하여 분무의 단면 분포를 측정하였고, 직접사진을 통하여 액적의 크기도 측정하여 PLIF의 결과와 비교하였다.

• 기계저널
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• 제33권12호
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• pp.1031-1042
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• 1993

연소현상에 대한 이해를 증가시키기 위하여 화염을 이용한 많은 실험적 연구가 이루어져 왔다. 특히 연소 모델의 개선과 증명을 위하여는 화염에서의 성분 농도 측정이 필수적이며, 최근에 들어 측정 가능해진 래디컬성분의 측정은 연소해석분야에 많은 진전을 가져왔다. OH, H 및 O는 연료의 분해 (decomposition) 및 연소 산화물생성 이외에도 CO와 NO 같은 공해물질의 형성등 연소과정에서 매우 중요한 래디컬들이며, 특히 화염영역에서의 OH의 전파(transport)는 화염의 점화 및 안정성 (stability)에도 큰 영향을 미친다. OH래디컬은 연소과정에서 가장 중요한 성분 중 하나이며, 또한 스펙트럼이 비교적 잘 알려져 있어 레이저 유도 형광의 적용이 용이하므로 화염에서의 OH농도 측정에 LIF(laser induced fluorescence) 또는 PLIF(planar laser induced fluorescence)가 널리 사용되고 있다. 따라서 LIF 및 PLIF의 원리 및 연소분야에서의 응용을 OH농도 측정을 중심으로 소개하고자 한다.

• 한국추진공학회지
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• 제9권4호
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• pp.55-65
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• 2005

에어 터보 램제트 엔진 연소기에서 연료와 공기의 혼합성능은 연소 효율과 안정성에 중요한 요인이 된다. 에어 터보 램제트 축소모형의 연소기에서 혼합기에 따른 혼합성능을 파악하기 위하여 두개의 꽃잎형 혼합기를 제작하였고, 각각에 대하여 연료 분포를 측정하였다. 2차원 연료 분포 측정에는 평면 레이저 유도 형광 기법을 사용하였다. 획득한 아세톤 형광 이미지는 이미지 처리 기법을 사용하여 정량적 연료 분포로 나타내었다. 이러한 연료 분포 이미지를 바탕으로 연료와 공기의 혼합성능이 좋은 혼합기를 알아내었다.