• 제목/요약/키워드: Icing phenomenon

검색결과 16건 처리시간 0.017초

액상분사식 LPG 연료공급방식의 아이싱현상에 관한 연구 (Investigation of Icing Phenomenon in Liquid Phase LPG Injection System)

  • 김창업;오승묵;강건용
    • 한국분무공학회지
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    • 제8권1호
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    • pp.9-15
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    • 2003
  • The liquid phase LPG injection (LPLI) system is considered as one of the next generation fuel supply systems for LPG, vehicles, since it can accomplish the higher power, higher efficiency, and lower emission characteristics than the existing mixer type fuel supply system. However, during the injection of liquid LPG fuel into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. A problem is that the moisture in the air freezes around the outlet of a nozzle, which is called icing Phenomenon. It may cause damage to the outlet nozzle of an injector. The frozen ice deposit detached from the nozzle also may cause a considerable damage to the inlet valve or valve seat. In this work, the experimental investigation of the icing phenomenon was carried out. The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of the air temperature in the inlet duct. Also, it was observed that the icing occurs first in the inlet of a nozzle, and grows considerably at the upper part of the nozzle inlet and the opposite side of the nozzle entrance. An LPG fuel, mainly consisting of butane, has lower latent heat of vaporization than that of propane, which is an advantage in controlling the icing phenomenon.

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액상분사식 LPG엔진 인젝터의 후적 및 아이싱 특성에 관한 연구 (A Study of Droplets and Icing Characteristics on Injector in a Liquid Phase LPG Injection Engine)

  • 김창업;최교남;강건용;박철웅
    • 한국분무공학회지
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    • 제12권1호
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    • pp.38-44
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    • 2007
  • Since the Liquid Phase LPG injection (LPLI) system has Advantages in power generation and emission characteristics compared to the mixer-type fuel-supply system, a variety of studies regarding LPLi system has been conducted and its applications are made in automobile industry. However, the heat extraction due to the evaporation of liquid fuel, causes not only a post-accumulation of fuel but also an icing phenomenon which is a frost of moisture in the air around the nozzle tip. Since there exists a difficulty in the accurate control of air fuel ratio in both fuel supply systems, it can result in poor engine performance and a large amount of harmful emissions. This research examines the characteristics of icing phenomenon and develops anti-icing bushing to prevent an icing on the surface of the injection tip. It was found that n-butane, which has a relatively high boiling point ($-0.5^{\circ}C$), was a main species of post-accumulation. Also the results show that the post-accumulation problem was allevaited the utilization of a large inner to outer bore ratio and smooth surface roughness. In addition, an icing phenomenon and its formation process were found to be mainly affected by the humidity and the temperature of inlet air in an inlet duct. Also, it was observed that an icing phenomenon is lessened using aluminum bushing whose end coincides with the end of fuel injection tip in length.

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LPG 액상분사식 인젝터에서 후적에 의한 아이싱 특성 연구 (Characteristics of Icing Phenomenon with Droplet of an Injector for Liquid Phase LPG Injection System)

  • 박철웅;김창업;최교남;강건용
    • 한국자동차공학회논문집
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    • 제15권5호
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    • pp.9-16
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    • 2007
  • Since the liquid phase LPG injection(LPLI) system has an advantage of higher power and lower emission characteristics than the mixer type fuel supply system, many studies and applications have been conducted. However, the heat extraction, due to the evaporation of liquid fuel, causes not only a dropping of LPG fuel but also icing phenomenon that is a frost of moisture in the air around the nozzle tip. Because both lead to a difficulty in the control of accurate air fuel ratio, it can result in poor engine performance and a large amount of HC emissions. The experimental investigation was carried out on the bench test rig in this study. It was found that n-butane, that has a relatively high boiling point($-0.5^{\circ}C$), was a main species of droplet composition and also found that the droplet problem was improved by the use of a large inner to outer bore ratio nozzle whose surface roughness is smooth. The icing phenomena were decreased when the an engine head temperature was increased, although a large amount of icing deposit was still observed in the case of $87^{\circ}C$. Also, it was observed that the icing phenomenon is improved by using anti-icing bushing.

액상분사식 LPG 인젝터의 아이싱 생성 특성 및 억제 방법 (Icing Characteristics in Liquid-Phase Injection of LPG Fuel)

  • 이선엽;김창업;최교남;강건용
    • 한국분무공학회지
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    • 제14권4호
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    • pp.147-152
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    • 2009
  • Since a liquid-phase LPG injection system allows accurate control of fuel injection and increase in volumetric efficiency, it has advantages in achieving higher engine power and lower emissions compared to the mixer type LPG supplying system. However, this system also leads to an unexpected event called icing phenomenon which occurs when moisture in the air near the injector freezes and becomes frost around the nozzle hole due to extraction of heat from surrounding caused by instant fuel vaporization. As a result, it becomes difficult to control air/fuel ratio in engine operation, inducing exacerbation of engine performance and HC emission. One effort to mitigate icing phenomenon is to attach anti-icing injection tip in the end of nozzle. Therefore, in this study, the effect of engine operation parameters as well as surrounding conditions on icing phenomenon was investigated in a bench test rig with commercially-used anti-icing injection tips. The test results show that considerable ice was deposited on the surface near the nozzle hole of the anti-icing tip in low rpm and low load operating conditions in ambient air condition. This is because acceleration of detachment of deposited ice from the tip surface was induced in high load, high rpm conditions, resulting in decrease in frost accumulation. The results of the bench testing also demonstrate that little or no ice was formed at surrounding temperature below a freezing point since the absolute amount of moisture contained in the intake air is too small in such a low temperature.

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대형 액상분사식 LPG엔진 인젝터의 아이싱 특성연구 (Characteristics of Icing Phenomenon on Injector in a Liquid Phase LPG Injection SI Engine)

  • 김창업;오승묵;강건용
    • 한국분무공학회지
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    • 제8권2호
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    • pp.1-6
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    • 2003
  • The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

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LPLi 엔진 인젝터의 결빙조각 형성이 연소 및 배기가스에 미치는 영향 (Visualization of the Icing at LPLi Engine Injector and the Effect of the Inflow of Ice Particle into Cylinder on the Combustion and the Exhaust Gas)

  • 박정철;김우석;이종화;이병옥;박경석
    • 한국자동차공학회논문집
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    • 제12권2호
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    • pp.39-44
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    • 2004
  • As air pollution has become an important issue across the world, studies of clean fuel are on going to reduce combustion emissions. One example is development of the LPLi(Liquefied Phase LPG injection) engine. Some problems are occurred during development. One of the problems is icing phenomenon at injector tip due to evaporation potential heat when liquid LPG is injected. If the Icing is raised at injector tip or injector inserting hole, it disturbs fuel injection. And if the ice particles are inducted into cylinder, it brings problems associated with control of emission and air/fuel ratio. In order to solve the problems, a rig system was set up and observed Icing of injector tip. Engine test was carried out for visualization of injector tip icing and its effects on combustion and emissions.

진동분석을 통한 회전익 드론의 블레이드 착빙 예지 (Prognosis of Blade Icing of Rotorcraft Drones through Vibration Analysis)

  • 이선우;도재석;허장욱
    • 한국군사과학기술학회지
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    • 제27권1호
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    • pp.1-7
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    • 2024
  • Weather is one of the main causes of aircraft accidents, and among the phenomena caused by weather, icing is a phenomenon in which an ice layer is formed when an object exposed to an atmosphere below a freezing temperature collides with supercooled water droplets. If this phenomenon occurs in the rotor blades, it causes defects such as severe vibration in the airframe and eventually leads to loss of control and an accident. Therefore, it is necessary to foresee the icing situation so that it can ascend and descend at an altitude without a freezing point. In this study, vibration data in normal and faulty conditions was acquired, data features were extracted, and vibration was predicted through deep learning-based algorithms such as CNN, LSTM, CNN-LSTM, Transformer, and TCN, and performance was compared to evaluate blade icing. A method for minimizing operating loss is suggested.

부탄과 프로판 혼합비율에 따른 액상 LPG 분사시 Icing 특성 (Icing Characteristics of Liquid Phase LPG Injection According to Butane and Propane Mixing Rates)

  • 김영진;조원준;이기형
    • 한국분무공학회지
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    • 제16권3호
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    • pp.146-151
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    • 2011
  • LPG(Liquified Petroleum Gas) fuel for vehicles has lots of advantages such as low emission level, cheaper fuel cost and enough infrastructure. Therefore it arouses interest as an alternative engine to reduce emission of diesel engines. Especially MPI(Multi Point Injection) type LPLi(Liquid Phase LPG injection) system could have overcome the disadvantages of mixer types such as low engine performance, decreased charging efficiency and cold starting difficulty. However ice formation on the nozzle tip and intake port due to the freezing of moisture around the components is often observed in LPLi systems. This icing phenomenon is the direct cause of unstable engine combustion, resulting in engine emissions. Therefore in this research, a spray visualization test for LPG injection was carried out to obtain the basic information of an LPLi injector, then the effects of butane and propane mixing rates on ice formation at the intake port and nozzle tip was investigated. As a result, the icing characteristics of them showed contrary results according to the mixing rates.

빙해선박 상부갑판 열선의 열전달 특성에 따른 착빙방지 성능평가 및 설계기준에 관한연구 (A Study on the Anti-Icing Performance Evaluating and Design Guide by Heating Coil for Upper Deck of Icebreaking Vessels)

  • 이종찬;서영교;이춘주
    • 대한조선학회논문집
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    • 제49권6호
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    • pp.541-549
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    • 2012
  • The study adopted a freezing prevention method of the upper deck which used heating coil, and carried out numerical analysis by using ANSYS 13.0 CFD for design guide of the vessel operating in cold region. It is based on the experimental results of the anti-icing performance tests which were carried at cold room chamber in MOERI. Numerical analysis for the design guide was performed by considering S.S.T. (Shear Stress Transport) turbulent model for flow separation effects and the turbulence which occurred in interfaces of the numerical model in order to express appropriate heat transmission phenomenon. The numerical result shows average temperature of the upper deck surface appeared similarly compared with the indoor chamber test. The design guide for optimum freezing prevention presented through heat transmission capability and interval of the heat coil in various outdoor temperature($10^{\circ}C{\sim}-30^{\circ}C$) and wind speed(1m/s~7m/s).

연료온도변화가 분무특성에 미치는 영향 (The Influence of Fuel Temperature on the Spray Characteristics)

  • 박병성;김호영;정진택
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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    • pp.173-178
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    • 2003
  • An experimental study is conducted to investigate the effects of fuel temperature on the spray characteristics of a dual-orifice type swirl injector which is used in gas turbines. The major parameters affecting spray characteristics are fuel temperature and injection pressure entering into the injector. Fuel temperature is shown to have strong influence on the spray characteristics especially at a lower temperature. In this study, fuel temperature is varied from $30^{\circ}C$ to $120^{\circ}C$ and injection pressure is altered from 3 to $7 kg_{f}$ /$cm^{2}$. Two kinds of fuel, which have different surface tension and viscosity, are chosen as an atomizing fluid. As a result, injection instability occurs in the low temperature range due to icing phenomenon and the change of fuel properties. As the injection pressure increases, the kinematic viscosity range for stable atomization becomes wider. The factor controlling the SMD of spray is substantially different depending on the fuel temperature range.

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