• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.251-255
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• 2005

By using liquid film thickness measurement the spray characteristics of swirl injector according to the geometric parameters were investigated in this paper. A specially designed injector having a variable backhole length, swirl chamber length, orifice length was used to measure the liquid film thickness. The spray characteristics of the injector were represented by mass flow rate according to the injection pressure, liquid film thickness in the lower orifice, spray cone angle.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.22-27
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• 1999

최근 정밀농업기술의 중요성이 인식되면서 점살포, 직접살포, 또는 방제목표물의 크기에 따른 분무량 조절 등의 기술이 개발되고 있으나 모든 기술이 분무량 조절에만 치중되어 있다. 일반적인 수압식 노즐의 경우에 분무압을 이용하여 분무량을 제어하면 분무입자의 크기가 적정 이외의 크기로 살포되어 효율적인 방제효과를 얻기가 어렵다. 하나의 제어인자 즉 분무압만을 이용하여 두 가지의 특성 즉 분무량과 분무입자의 크기를 조절하는 것은 이론적으로 불가능하다 정밀방제에 있어 분무입경과 분무량을 독립적으로 조절할 수 있으려면 두 가지 제어인자를 가진 노즐을 이용해야만 가능하며 이러한 범주에 속하는 노즐로는 원심노즐과 이류체노즐, 정전화노즐 등이 있다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.988-991
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• 2010

본 연구는 직접 연료분사 가솔린 엔진에 장착되는 고압연료 인젝터의 연료공급 특성에 대한 것으로, 두 종류 GDI 인젝터의 분무가시화 실험을 수행하였고, 분무특성을 분석하였다. 가시화 실험을 통하여 인젝터 끝단 분사 초단부근 연료거동을 확인하였고, 인젝터의 특성인 도달거리와 관통력을 확인하였으며, 분위기 압력의 변화에 따른 분무특성을 고려하여 실험을 수행하였다. 두 인젝터 모두 분위기 압력이 증가함에 따라 도달거리와 분사각이 감소하였다. B type의 인젝터 보다 A type의 인젝터가 분위기 압력에 민감한 것으로 나타났다. 본 연구를 통하여 분위기 압력의 변화에 따른 분무거동의 변화를 확인 하였으며 직접 분사인젝터의 엔진적용을 위한 기초 분무 데이터를 확보하였다.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.167-173
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• 2014

The spray characteristics of Gas-Centered Swirl Coaxial Injector was investigated that there were different characteristics with or without gas flow. As gas flow was accelerated, the momentum of gas was transferred to the momentum of liquid in the low liquid Reynolds number. Therefore, the axial velocity of liquid was increased and the measured value was smaller than without gas flow. However, in the high momentum flux ratio, the momentum transfer hardly occurred and the results had constant values. As the recess length was increased, the mixing area of gas and liquid also was increased, the results were decreased.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.410-415
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• 2000

A diesel engine is one of the major prime movers to its high thermal efficiency. But due to the recent attention far the environmental pollution, the emissions of diesel engine became to a important problem. So it is needed to understand the characteristics of diesel spray injected into a combustion chamber. The factor which controls the diesel spray are the injection pressure, the nozzle diameter, the impinging angle and the variation of pressure and temperature. In this paper, experiments were conducted far the variation of the environmental temperature(273k, 373k, 573k), free spray and impinging spray. And the notions of penetration, spray angle, axial distance for free spray, and axial distance, spray thickness from impinging wall fur impinging spray.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.454-459
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• 2000

Diesel engine which has high thermal efficiency is one of the major movers. Recently, as people pay attention to the environmental pollution, the emission of Diesel engine becomes an important problem. So it is needed to understand the characteristics of diesel fuel spray injected into a combustion chamber to reduce the emission. The factors which control the diesel fuel spray are the injection pressure, the nozzle diameter, the impinging angle and the variation of an ambient pressure and temperature. In this paper, the experiments were conducted in the free spray and the impinging spray with various ambient temperatures(273K, 373K, 573K). And the behaviors of the diesel fuel spray, such as penetration, spray angle and axial distance in the free spray and axial distance and spray thickness in the impinging spray were studied.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.186-190
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• 2006

This study was performed to investigate the characteristics of a co-axial swirl injector. Especially to predict the initial liquid sheet thickness and spray cone angle of an outer orifice a concept of effective area was introduced from hydraulic analysis. In addition, the parameters determining the characteristics of a co-axial swirl injector were re-defined around outer orifice. The calculated results-SMD, spray cone angle, and spray thickness agreed well with the test results qualitatively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.202-206
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• 2009

We studied the spray characteristics of the high-speed rotating fuel injection system. The diameter of in-line injection orifices are varied from 1mm to 5mm and the number of in-line injection orifices are varied from 3 to 12. Droplet size, velocity and spray distribution were measured by the PDPA(Phase Doppler Particle Analyzer) system and spray was visualized. From the test results, the liquid column generated from the injection orifice is mainly controlled by the rotational speeds. Also diameter of injection orifices and number of injection orifices have influence on the diameters of droplet. Consequently, we find out that the basic mechanism of controlling the droplet size is the liquid film thickness in the injection orifice.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.969-974
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• 2011

A carbon nanotube (CNT) is a cylindrical carbon nanostructure with good transport properties along the tube's axis. As an approach for realizing the practical use of CNTs, CNT networks are fabricated and their applications in many fields are investigated. To fabricate thin CNT-based films, several methods have been proposed and used. Among these methods, the spray coating method is a robust method for fabricating a large area. However, it is difficult to achieve uniformity in the CNT network. To solve this problem, it is necessary to understand the effect of the sprayprocess parameters on the deposition thickness distribution. In this study, a numerical model for predicting the deposition thickness distribution during the spray process was developed. The spatial deposition thickness distributions obtained according to various nozzle paths were analyzed using the developed numerical model.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.6
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• pp.41-47
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• 2009

This paper presents the spray characteristics of the simplex fuel nozzle with different working fluids for the gas turbine engine. Spray characteristics can be changed with viscosity, surface tension and density. In this research, water and test fluid type 2 which has similar characteristics of the kerosene are used as a working fluid. Spray visualization was performed by using ND-Yag laser and droplet size was measured by using PDPA(Phase doppler particle analyzer) system. The test results show that spray shapes and SMD distributions of two working fluids are similar at main spray region.