• Title/Summary/Keyword: Schlieren Photograph

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A study on the spray and flame by optically accessible D.I. diesel engine : analysis by Schlieren method and diffused background illumination method (가시용 직분식 디젤기관의 분무와 화염에 관한 연구)

  • 안수길;이덕보;라진홍
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.3
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    • pp.9-23
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    • 1995
  • To analyze the spray and flame in D.I. diesel engine, the visualizing methods by schlieren photograph and diffused background illumination photograph with high speed camera are applied to optically accessible D.I.diesel engine. Wcaporating spray, spray droplets and brightness flame are taken with high speed camera by visuallizing method in accordance with various suction air temperature and injection time. The spray and flame image on the film was analyzed by image analyzer. The optically accessible D.I. diesel engine had the similar pressure characteristic to the real D.I. diesel engine. Experimental results showed that shadow areas of the evaporating spray were extended at higher suction air temperature, spray droplets had a max. Penetration length and their penetrating patterns were dependent on the surrounding gas temperature, and flame size after ignition was largely governed by the evaporated fuel quantity at ignition point and by the surrounding gas condition due to piston motion.

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SIMULATION OF EXPERIMENTAL VISUALIZATION METHODS FOR COMPUTATIONAL FLUID DYNAMICS RESEARCH

  • TAMURA Y.;FUJII K.
    • 한국전산유체공학회:학술대회논문집
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    • 1995.04a
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    • pp.44-68
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    • 1995
  • In the present paper, visualization techniques in fluid dynamic experiments such as Schlieren photograph are numerically simulated so that the same output as the experimental flow visualization can be obtained from the computed results for the fair comparison. Numerical methods to simulate optical visualizations, that are Schlieren photograph, shadowgraph and interferogram, are considered. Some examples of pictures obtained by the present methods show the importance of the simulations of visualization techniques for the correct comparisons of the computations and experiments.

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Combustion Characteristics in a Constant Volume Combustion Chamber with Sub-Chamber (II) Effect of Combustion Promotion with Configuration Change of the Critical Passagehole (부실식 정적연소실내 연소특성에 관한 연구 (II) 임계연락공의 형상변화에 따른 연소촉진효과)

  • 김봉석;권철홍;류정인
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.10
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    • pp.2611-2623
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    • 1993
  • To construct the design back data for a lean-burn gas engine, we investigated the combustion characteristics in the main chamber using a constant volume combustion chamber with subchamber. The combustion characteristics with configuration change of the critical passageholes have been studied by taking pressure data, schlieren photograph, ion current and light emission signal of flame. Heat release rate with various critical passageholes also have been analysed by using the combustion model of a prechamber diesel engine. It was found that combustion characteristics in the main combustion chamber were greatly influenced by the geometric configurations of critical passagehole.

Behavior of 2-Stage Injection on Diesel Spray (2단분사 디젤분무의 거동)

  • Park, B.D.;Kwon, S.I.;Oh, J.G.;Kim, S.J.
    • Journal of ILASS-Korea
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    • v.5 no.4
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    • pp.33-39
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    • 2000
  • The behavior of the 2-stage spray was studied by using the schlieren method with the high pressure common-rail injection system. The spray injected 2 times with the interval of $0.3ms{\sim}1.5ms$ between the 1st and the 2nd spray in a modeled combustion chamber of constant volume bomb. In this case, the quantity of injected fuel of 1st and 2nd also changed. The schlieren photograph shows that the 2nd spray goes further away than the 1st spray when the quantity of the 1st spray is less than that of the 2nd spray. The dispersion of the vapour to the combustion chamber is not affect in a 10% of 1st spray quantity. When the 1st spray quantity is more than the 2nd spray, the vapour scattering of spray is good.

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An Experimental Study on Flame Structure and Combustion Characteristics of Turbulent Diffusion Flame(I) (난류확산화염의 화염구조와 연소특성에 관한 실험적 연구)

  • Choe, Byeong-Ryun;Jang, In-Gap;Choe, Gyeong-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.3
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    • pp.1028-1039
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    • 1996
  • This study was focused on the examination of the flame structure and the combustion characteristics of diffusion flame which was formed the turbulent shear flow of a double coaxial air jet system. The shear flow was formed by the difference velocity of surrounding air jet(U$\_$s/) and center air jet (U$\_$c/). So experimental condition was divided S-type flame (.lambda. > 1) and C-type flame (.lambda. < 1) by velocity ratio .lambda. (=U$\_$s//U$\_$c/). For examination of the flame structure and the combustion characteristics in diffusion flame, coherent structure was observed in flame by schlieren photograph method. We measured fluctuating temperature and ion current simultaneously and accomplished the statistical analysis of its. According to schlieren photograph, the flame was stabilized in the rim of the direction of lower velocity air jet, coherent eddy was produced and developed by higher velocity air jet. The statistical data of fluctuating temperature and ion current was indicated that reaction was dominated by higher velocity air jet. The mixing state of burnt gas and non-burnt gas was distributed the wide area at Z = 100 mm of C-type flame.

An Experimental Study on Flow Characteristics of a Supersonic Impinging Jet (초음속 충돌제트의 유동특성에 대한 실험적 연구)

  • 신필권;신완순;이택상;박종호;김윤곤
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.3
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    • pp.10-19
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    • 1998
  • When an under-expanded supersonic jet impinges on an inclined flat surface, a complex flow structure is established due to the intersection between the flat surface and the shock system of the free jet. This study reports on an experimental results of flows due to under-expanded axisymmetric sonic jets impinging on flat plate. Plate inclination from $60^{\cire}$~$90^{\cire}$ were investigated by means of detailed measurements of the surface pressure and schlieren photograph and surface flow visualization. The schlieren photograph are consistent with the pressure distribution and the surface flow visualization pictures are clearly related to the pressure distributions. The maximum wall pressure is found to be large on the inclined plate than on the perpendicular plate.

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Experimental Study on Stream Turbine Cascade Flow (증기터빈 익렬유동에 관한 실험적 연구)

  • 권순범;윤의수;김병지
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.8
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    • pp.2177-2183
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    • 1994
  • The rapid expansion or condensible gas such as moist air of steam gives rise to nonequilibrium condensation. As a result of irreversibility of condensation process in the supersonic cascade flow of low pressure steam turbine, the entropy of the flow is increased, and the efficiency of the turbine is decreased. In the present study, to investigate the flow of moist air in 2-dimensional cascade made as the configuration of the tip section of the last actual steam turbine moving blade, the static pressure at both sides of pressure and suction of blade are measured by static pressure taps and the distribution of Mach number on both surfaces of the blade are obtained by using the measured static pressure. Also, the flow field is visualized by a schlieren system. From the experimental results, the effects of the stagnation temperature and specific humidity on the flow properties in a 2-dimensional stationary cascade of a practical steam turbine blade are clearly identified.

The Experimental study on the Flame Propagation Process of a Constant Volume Combustion Chamber (정적 연소실내에서 화염 전파 과정에 대한 실험적 연구)

  • Kim, Chun-Jung;Kang, Kyung-Koo
    • Journal of the Korean Society of Industry Convergence
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    • v.2 no.1
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    • pp.121-130
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    • 1999
  • It is necessary to measure pressure, temperature, chemical equilibrium and the shape of flame in order to understand the combustion process in a combustion chamber. In particular, the flame formulation and combustion process of divided combustion chamber are different from those of a single chamber, And the variable diameter of a jet hole can effect not only physical properties like ejection velocity, temperature and time of combustion but also a chemical property like the reaction mechanism. Accordingly temperature is one of the most important factors which influence the combustion mechanism. This paper observed shape of flame by using the schlieren photographs and measured the pressure in a combustion chamber and the reaching time of the flame by ion probe By doing these, we investigation the formulation of the flame and the process of propagation. These measurement methods can be advanced in understanding the combustion process and process and propagation of flame.

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선회류를 동반하는 난류확산화염에 관한 실험적 연구

  • 양옥룡;이근오
    • Journal of the korean Society of Automotive Engineers
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    • v.7 no.2
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    • pp.34-44
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    • 1985
  • Swirling flows have commonly used for a number of years for the stabilization of high- intensity combustion processes. In general, these swirling flows are poorly understood because of their complexity. This paper, therefore, deals with the experimental study on turbulent diffusion flames with swirling flow in unburned flow field by using a model combustor. The purpose of this study is to investigate quantitatively the swirling air jets issuing from vane swirlers. The fundamental experiments have been performed for the local velocity distribution, turbulence intensity and Schlieren photograph in th jets issuing into the atmosphere.

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An experimental Investigation on Flame spreading over liquid fuel surface (액체 연료 표면에서의 화염확장기구에 관한 실험적 연구)

  • 김한석
    • Fire Science and Engineering
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    • v.7 no.1
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    • pp.5-10
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    • 1993
  • Flame spreading over liquid fuel surface has been investigated using thermocouple and schlieren photograph. Without forced convection, it was clearly found that the flame spreading is mainly controlled by surface flow which is maybe generated by change of surface tension. Furthermore, the radiative heat transfer is dominant over a conductive heat transfer in kerosene. But the latter was found more influential than the former in diesel. Oscillation of flame spreading was found. It maybe cause of surface flow.

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