• 한국분무공학회지
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• 제7권1호
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• pp.36-42
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• 2002

The objective of this investigation was to obtain an excellent spray at the low injection pressure. When cavitation occurred in the nozzle hole the atomization of the liquid jet enhanced considerably. In this experiments, a acrylic nozzle which was installed the gap and installed the bypass in the nozzle hole was used to enhance the atomization of the liquid jet at the few injection pressure. The liquid flow in the nozzle hole was photographed by a transmitted light using a micro flash. The spray angle was measured by macroscope images of PMAS and the Sauter mean diameter was measured by PDA system. The pressure of the notate hole was measured by pressure transducer. It was found that enhanced atomization of the liquid jet at the low injection pressure was obtained by installing the gap and the bypass at the single hole nozzle.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.395-398
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• 2010

감압비등에 의한 미립화는 더 미세한 직경의 액적을 얻을 수 있고, 분무각이 증가하며, 더 좋은 혼합특성을 갖는 다는 점에서 단순 압력식 미립화와 차이가 난다. 감압비등이란 과열된 액체를 포화 압력 이하의 대기 중으로 분사하여 급격한 비등에 의해 이루어지는 미립화이다. 본 연구는 금속 연료를 이용한 추진기관의 산화제인 물 공급기술에 감압비등과정을 이용한 와류분무를 적용시키기 위해 수행됐다. 분열길이와 같은 거시적 특성은 Charge-Couple Device(CCD) 카메라를 이용해 측정하였고, Sauter Mean Diameter(SMD)와 SMD분포와 같은 미시적 특성은 Global Sizing Velocimetry(GSV) 시스템을 이용해 측정했다. 실험은 압력과 온도, 대류 속도를 변화시키며 진행했다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.1-5
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• 2008

An experimental study was performed to develop the rotational fuel injection system of the micro turbojet engine. In this system, fuel is sprayed by centrifugal forces of engine shaft. The test rig was designed and manufactured to get droplet information on combustion space. This experimental apparatus consist of a high speed rotational device(Air-Spindle), fuel feeder, rotational fuel injector and acrylic case. To understand spray characteristics, spray droplet size, velocity and distribution were measured by PDPA (Phase Doppler Particle Analyzer) and spray was visualized by using Nd-Yag laser-based flash photography. From the test results, the length of liquid column from injection orifice is controlled by the rotational speeds and Sauter Mean Diameter(SMD) is decreased with rotational speed. Also, Sauter Mean Diameter is increased as increasing mass flow rate at same rotational speeds.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.73-80
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• 2002

Dimethyl ether (DM) is one of the most attractive alternative fuel far compression ignition engine. Its main advantage in diesel engine application is high efficiency of diesel cycle with soot free combustion though conventional fuel injection system has to be modified due to the intrinsic properties of DME. Experimental study of DME and conventional diesel spray employing a common-rail type fuel injection system with a 5-holes sac type injector (hole diameter 0.168 ㎜/hole) was performed in a high pressure chamber pressurized with nitrogen gas. A CCD camera was employed to capture time series of spray images followed by spray cone angles and penetrations of DME were characterized and compared with those of diesel. Under atmospheric pressure condition, regardless of injection pressure, spray cone angles of the DME were wider than those of diesel and penetrations were shorter due to flash boiling effect. Tip of the DME spray was farmed in mushroom like shape at atmospheric chamber pressure but it was disappeared in higher chamber pressure. On the contrary, spray characteristics of the DME became similar to that of diesel under 3MPa of chamber pressure. Hole-to-hole variation of the DME spray was lower than that of diesel in both atmospheric and 3MPa chamber pressures. At 25MPa and 40MPa of DME injection pressures, regardless of chamber pressure, intermittent DME spray was observed. It was thought that vapor lock inside the injector was generated under the two injection pressures.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.171-174
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• 2008

소형 회전연료 분사장치의 분열과정 특성을 연구하기 위한 실험적 연구를 수행하였다. 이러한 분열과정의 특성을 이해하기 위해 PDPA(Phase Doppler Particle Analyzer)시스템을 사용하여 분무입자의 크기와 속도를 측정하였다. 또한 Nd-Yag Laser를 광원으로 사용하여 분무를 가시화하였다. 실험결과 Injection Orifice로부터 생성된 액주는 회전수에 의해 지배되고, SMD(Sauter Mean Diameter)와 분무특성은 Injection Orifice의 직경에 큰 영향을 받는다는 것을 알 수 있었다.

• 한국분무공학회지
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• 제19권1호
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• pp.1-8
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• 2014

Liquefied petroleum gas (LPG) is regarded as an alternative fuel for spark ignition engine due to similar or even higher octane number. In addition, LPG has better fuel characteristics including high vaporization characteristic and low carbon/hydrogen ratio leading to a reduction in carbon dioxide emission. Recently, development of LPG direct injection system started to improve performance of vehicles fuelled with LPG. However, spray characteristics of LPG were not well understood, which is should be known to develop injector for LPG direct injection engines. In this study, effects of operation condition including ambient pressure, temperature, and injection pressure on spray properties of n-butane were evaluated and compared to gasoline in a multi-hole injector. As general characteristics of both fuels, spray penetration becomes smaller with an increase of ambient pressure as well as a reduction in the injection pressure. However, it is found that evaporation of n-butane was faster compared to gasoline under all experimental condition. As a result, spray penetration of n-butane was shorter than that of gasoline. This result was due to higher vapor pressure and lower boiling point of n-butane. On the other hand, spray angle of both fuels do not vary much except under high ambient temperature conditions. Furthermore, spray shape of n-butane spray becomes completely different from that of gasoline at high ambient temperature conditions due to flash boiling of n-butane.

• 한국분무공학회지
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• 제9권4호
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• pp.9-16
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• 2004

A study of the propeny and performance effect of Indolene - Methanol Plus High Alcolhols (MPHA) has been completed. This study invested the measurement of fuel properties and performance parameters. The fuel properties investigated are distillation characteristics, heating valuer flash point, specific gravity and water tolerance. The performance parameters measured are minimum advance for best torque (MBT) spark timing, power output. The alcohol concentration was varied from 0 to 100 percent by volume in clear Indolene. The measurement of fuel properties indicated that, in general, Indolene - MPHA blends have higher water tolerance, similar specific gravity, similar flash point and different distillation characteristics compared to Indolene - Methanol blends. The performance parameters were measured using a single cylinder spark ignition engine at different compression ratios. The results of the performance measurements indicated that Indolene - MPHA blends have a higher MBT spark advance, similar power output.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.952-957
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• 2001

The objectives of this investigation were to obtain an excellent spray by cavitation under the low injection pressure. When cavitation occurs in the nozzle hole, the atomization of the liquid jet enhanced considerably. In this experiments, a acrylic nozzle made the gap and installed the bypass in the nozzle hole was used to enhance the atomization of the liquid jet at the low injection pressure. The liquid flow in the nozzle hole was photographed by a transmitted light using a micro flash. The spray angle was measured macroscope images of PMAS and the Sauter mean diameter was measured PDA system. To measure the pressure of the nozzle hole, pressure transducer was used. The results of this study indicated that enhanced atomization of the liquid jet at the low injection pressure was obtained by making the gap and installing the bypass at the single hole nozzle.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6098-6105
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• 2013

본 연구에서는 해수용 열교환기 적용을 위한 열분사코팅의 종류에 따른 부식특성 및 열전도 성능을 조사하기 위해 실험이 수행되었다. 코팅은 아연과 알루미늄을 열분사코팅한 뒤 실리콘 및 에폭시 수지를 추가 도포한 시편을 선정하였다. 코팅의 부식특성 변화를 관찰하기 위하여 사이클릭 선도변화 측정 및 SEM촬영을 이용하였다. 시편의 열전도 성능을 측정하기 위해서 레이저 확산법을 이용하여 열전도도를 비교하였으며 추가도포를 실리콘으로 한 경우 3 ~ 4% 에폭시로 한 경우 70 ~ 75%의 열전도도 하락이 발생하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.354-358
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• 2007

초소형 터보제트엔진에 적용되는 슬링거 인젝터 시스템의 분무특성을 파악하기 위한 연구를 수행 하였다. 이 연료 분사시스템은 엔진의 회전축으로부터 발생된 원심력에 의하여 연료가 연소기 내부로 공급되고, 액체연료의 미립화를 초래한다. 시험장치는 고속으로 회전하는 Spindle, 슬링거 인젝터, 가압식 물탱크, 아크릴 케이스로 구성하였다. 분무입자의 크기 및 속도를 측정하기 위해 PDPA(Phase Doppler Particle Analyzer) 시스템을 사용하였고, Nd-Yag Laser를 광원으로 사용하여 분무를 가시화 하였다. 시험결과 SMD(Sauter Mean Diameter)는 회전수, 유량, Injection Orifice 수에 큰 영향을 받는 것으로 나타났다. 이러한 실험적 연구로부터 이 시스템의 분무특성을 이해할 수 있었고, 초소형 터보제트엔진에 적합한 슬링거 인젝터의 형성을 도출할 수 있었다.