• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.4
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• pp.44-50
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• 1999

For the prediction of combustion performance of the Unlike Impinging Quadlet Injector (OOOF type), mixing efficiency, mixing characteristic velocity, and efficiency of mixing characteristic velocity were obtained from the cold test. Water/kerosene were used for simulants, The momentum ratio of oxidizer and fuel were mixing correlating parameter. Orifice discharge coefficient, spray pattern and mass distribution were measured. As a result, invasion-depth had strong effect on mixing efficiency, mixing characteristic velocity, and efficiency of mixing characteristic velocity. Mixing efficiency and efficiency of mixing characteristic velocity showed maximum value for momentum ratio 1.67(TMR = 2.5), and fuel rich state showed larger decreasing ratio than oxidizer rich state.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.126-142
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• 2020

This study aims to provide basic design data for a pintle injector and its combustion device through case study on the research and development of combustion devices to which a liquid-liquid pintle injector was applied. From data analysis, it was possible to provide the initial dimension of the combustion chamber and pintle injector based on the engine thrust, and the geometric characteristics of the high-efficiency injector. In addition, the pintle tip heat damage prevention mechanism and materials, face-shutoff pintle injector implementation method, and central propellant selection criteria were summarized. Theses results will be used as basic data for the design criteria of an initial pintle injector combustion device.

• Journal of ILASS-Korea
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• v.8 no.3
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• pp.10-18
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• 2003

In this paper, experimental study on the wan impingement spray of the common-rail diesel injector is performed. To examine the effect of various factors on the development of spray impinging on the wall, experiments were conducted at the various injection pressures. ambient pressures, wan distances from the injector tip, wall temperatures, and angles of wall inclination. The behaviors of the impingement spray ate visualized by using laser sheet methods and a ICCD camera. It is shown that the spray path penetration of the wall impingement spray increases with the increase of injection pressure, wall distance. wall temperature, wall angle. On the other hand the spray path penetration of the wan impingement spray decreases with the increase of ambient pressure.

• Journal of ILASS-Korea
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• v.8 no.3
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• pp.19-26
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• 2003

In this study, experimental study on atomization characteristics of the fuel spray impinging on the wall was at different wall distances and angles of wall inclination. The fuel injection system was composed based on the common rail system. and the injection signal was synchronized by the delay generator. The atomization characteristics of the injected spray were analyzed in terms of the SMD and velocities which were measured by using the phase Doppler particle analyzer system. It is revealed that the free spray is atomized actively above 50mm form the injector tip. In the cases of the impinged spray, the 5MD and velocity of the impinged spray are smaller than those of the free spray. The impinged spray has the maximum near the 35mm of the radial distance from the injector axis, and the atomization performance is enhanced with the decrease of the wall distance.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.174-181
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• 1998

Experimental and analytical studies are presented to characterize the break-up mechanism and atomization processes of the intermittent- impinging-type nozzle. Gasoline jets passing through the circular nozzle with the outlet diameter of 0.4mm and the injection duration of 10ms are impinged on each other. The impingement of fuel jets forms a thin liquid sheet, and the break-up of the liquid sheet produces liquid ligaments and droplets subsequently. The shape of liquid sheets was visualized at various impinging velocities and angles using the planer laser induced fluorescence (PLIF) technique. Based on the Kelvin-Helmholtz wave instability theory, the break-up length of liquid sheets and the droplet diameter are obtained by the theoretical analysis of the sheet disintegration. The mean diameter of droplet is also estimated analytically using the liquid sheet thickness at the edge and the wavelength of the fastest growing wave. The present results indicate that the theoretical results are favorably agreed with the experimental results. The size of droplets decreases after the impingement as the impinging angle or the injection pressure increase. The increment of the injection pressure is more effective than the increment of the impinging angle to reduce the size of droplets.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.384-394
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• 2005

Important characteristics of impinging sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spay data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline increase. The maximum SMD appeared the top of the SMD distribution

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.5-7
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• 2012

This study presents relations between the time lag and interaction index of the impinging-jet injectors using time lag model in a model chamber. To analyze the response of the flame, 5% amplitude of oxidizer velocity is artificially perturbed at a resonance frequency. At the mixing point of fuel and oxidizer, which determines the characteristic length, the relationship between velocity perturbation and heat release rate is quantified by combustion parameters of interaction index and time lag. As the improved method to apply the time-lag, the method using the average velocity obtained from numerical results is suggested.

• Journal of ILASS-Korea
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• v.2 no.4
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• pp.22-28
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• 1997

In this paper an experimental study of a spray created by two impinging jets is presented utilizing a novel two-reference-beam double-pulse holographic technique. Visualization of the overall spray pattern as well as measurements on the size and velocity of the droplets were performed with the special emphasis on the effect of physical properties of liquids. The overall spray pattern clearly revealed the inherent wave nature In the disintegration process of this type of atomization. The structure of liquid elements near the impingement point is indicative of the mechanisms of the disintegration process. Surface tension plays an important role in the droplet size without any noticeable effect on the spray pattern, whereas viscosity affects the structure without any significant effect on the droplet sire. The droplet velocities were not affected by liquid properties.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.217-220
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• 2009

This paper presents experimental results of Recess Characteristic of Swirl Coaxial Injector of fuel-rich gas generators. It was revealed that the internal impinging phenomenon played an important role in the spray characteristics, such as spray angle and breakup length.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.70-75
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• 2012

In this paper, the regression rate of the End-Burning Hybrid Rocket with variation of swirl intensity was investigated experimentally with the variation of fuel diameter, injector shape and angle. When fuel grain diameter is large, fuel mass flow rate increases. And the injector diameter increase, fuel regression rate decrease. The impinging effect of oxidizer flow on fuel surface for fuel combustion efficiency is stronger than swril effect in this End-burning propulsion system. The relation between the regression rate, oxidizer mass flux and swirl intensity was obtained.