• 제목/요약/키워드: In-Cylinder Gas Flow

검색결과 200건 처리시간 0.029초

흡기 유동 조건의 변화가 실린더 내 가스 유동 패턴에 미치는 영향 (Influence of Flow Conditions of Intake Air on Gas Flow Patterns in Engine Cylinder)

  • 이창식;전문수;김우경;최수천
    • 한국자동차공학회논문집
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    • 제7권8호
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    • pp.17-23
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    • 1999
  • This paper presents the characteristics of the gas flow in the engine cylinder under various intake flow conditins. The particle tracking velovimetry(PTV) was used to anlayze the gas flow pattern and flow field in the cylinder. Effects of tumble intensifying valve(TIV), swirl intensifying valve(SIV) and one-valve deactivated condition on in-cylinder flow patterns were compared with the baseline engine udner 600rpm motoring condition. In addtion, tumbel ration was estimated rwith results of in -cylinder flow fields. Base on experimental results, the tumble ration of in-cylinder flow field has the maximum value at the bottom dead center for the different four inlet conditions. In TIV condition, the tumble ration is 1.35 times larger than that of baseline engine and 1 intake valve deactivated condition is effective to improve in-cylinder swirl motion.

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천연가스엔진의 실린더내 흡기유동개선에 관한 연구 (A Study on the Improvement of In-Cylinder Flow Motion in the Natural Gas Engine)

  • 서승우;정동수;오승묵;최교남
    • 연구논문집
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    • 통권23호
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    • pp.121-126
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    • 1993
  • In general, natural gas engine converted from gasoline engine has disadvantage of power decrease. In order to increase power output in natural gas engine, the improvement of in-cylinder flow motion has been believed as the most effective method. In this study, the geometry of combustion chamber in 4 valve DOHC natural gas engine is modified, and in-cylinder flow patterns are analyized. Also engine performance is evaluated according to the modification of in-cylinder flow motion.

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Investigation of In-Cylinder Flow Patterns in 4 Valve S. I. Engine by Using Single-Frame Particle Tracking Velocimetry

  • Lee, Ki-hyung;Lee, Chang-sik;Chon, Mun-soo
    • Journal of Mechanical Science and Technology
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    • 제15권1호
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    • pp.108-116
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    • 2001
  • The in-cylinder flow field of gasoline engine comprises unsteady compressible turbulent flows caused by the intake port, combustion chamber geometry. Thus, the quantitative analysis of the in-cylinder flow characteristics plays an important role in the improvement of engine performances and the reduction of exhaust emission. In order to obtain the quantitative analysis of the in-cylinder gas flows for a gasoline engine, the single-frame particle tracking velocimetry was developed, which is designed to measure 2-dimensional gas flow field. In this paper, influences of the swirl and tumble intensifying valves on the in-cylinder flow characteristics under the various intake flow conditions were investigated by using this PTV method. Based on the results of experiment, the generation process of swirl and tumble flow in a cylinder during intake stroke was clarified. Its effect on the tumble ratio at the end of compression stroke was also investigated.

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입자 추적법을 이용한 4 밸브 가솔린 기관의 실린더 내 텀블 유동 특성 (Characteristics of Tumble Flow in Cylinder of 4 Valve Gasoline Engine by Using Particle Tracking Method)

  • 이창식;전문수;정성환
    • 대한기계학회논문집B
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    • 제23권9호
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    • pp.1178-1184
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    • 1999
  • The in-cylinder flow field of gasoline engine comprises unsteady compressible turbulent flows caused by the intake port, combustion chamber geometry and the change of the spatial shape. Thus the quantitative analysis of the in-cylinder bulk flow plays an important role in the improvement of engine performances and the reduction of exhaust emission. The influences of tumble intensifying valve (TIV) and swirl intensifying valve (SIV), and various intake-flow conditions are compared with the tumble ratio obtained by the measured results of the in-cylinder gas flow. In order to obtain the quantitative analysis of the in-cylinder gas flows of gasoline engine this investigation applied the particle tracking method to the analysis of gas flow characteristics. Various intake conditions such as tumble and swirl intensifying valve, the deactivated condition of one valve among two intake valves, and the other factors of gas flow are considered.

실린더내 흡기유동개선이 천연가스엔진의 연소성능에 미치는 영향 연구 (A Study on the Combustion Performance by the Improvement of In Cylinder Flow Motion in the Natural Gas Engine)

  • 정동수;서승우;오승묵;엄종호;장영준
    • 한국자동차공학회논문집
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    • 제3권3호
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    • pp.90-96
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    • 1995
  • In general, natural gas engine converted from gasoline engine has disadvantage of power decrease. In order to increase power output in natural gas engine, the improvement of in-cylinder flow motion has been believed as the most effective method. In this study, the geometry of combustion chamber in 4 valve DOHC natural gas engine is modified, and in-cylinder flow patterns is analyized. Also engine performance is evaluated according to the modification of in-cylinder flow motion.

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반도체용 특수가스 공급을 위한 가스캐비닛 내부 유동해석에 관한 연구 (A study on the Internal Flow Analysis of Gas Cylinder Cabinet for Specialty Gas of Semiconductor)

  • 김정덕;한승아;양원백;임종국
    • 한국가스학회지
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    • 제24권5호
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    • pp.74-81
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    • 2020
  • 일반적으로 반도체를 제조할 때는 인화성, 독성, 부식성의 유해·위험물질이 다수 사용되며, 특히 화학적 증착(CVD), 식각(Etch) 등의 공정에서는 특수가스를 사용하여 반도체를 제조하고 있다. 특수가스는 압축 또는 액화가스의 상태로 용기에 충전되어 있는데, 특수가스를 반도체 제조공정에 공급하는 설비로서 가스캐비닛(Gas Cylinder Cabinet)이 사용되고 있다. 이러한 가스공급시스템 내에서 실린더 이상 발생 시 배관·계측기 등 공급시스템의 안전 확보를 위해 가스실린더에 설치된 압력방출장치를 통해 가스가 방출하게 되는데, 이 경우 가스캐비닛 내부에 방출되는 가스가 캐비닛 외부로 누출될 위험성이 존재한다. 따라서 가스캐비닛 내부의 유체유동을 분석하여 누출에 따른 위험성을 파악하고 이에 대한 위험도 감소를 위한 대책을 제시하고자 한다.

특성곡선법을 이용한 디젤엔진 가스유동 1차원 수치해석의 타당성 평가 (Validation of diesel engine gas flow one-dimensional numerical analysis using the method of characteristics)

  • 김경현;공경주
    • 수산해양기술연구
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    • 제56권3호
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    • pp.230-237
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    • 2020
  • In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

실린더형 기-액 원심분리기 내의 유동특성 연구를 위한 CFD 시뮬레이션 (CFD Simulation to Study Flow Characteristics in Cylindrical Gas-Liquid Cyclone Separator)

  • 박경도;박종천;김경미
    • 한국해양공학회지
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    • 제28권4호
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    • pp.280-287
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    • 2014
  • In this paper, the numerical simulation of the gas-liquid flow in a cylinder cyclone separator is performed to investigate the flow characteristics using a commercial software, FLUENT, which solves the Reynolds-averaged Navier-Stokes(RaNS) equations. First, a single-phase flow with water in a gas-liquid cylinder cyclone(GLCC) separator is simulated and compared with the experiments(Farchi, 1990) and numerical simulations(Erdal, 1997). Then, the characteristics of the multi-phase flow for water-air, mud-only, and mud-air cases are discussed in the view point of the feasibilities for a mud handling system.

중속 디젤엔진의 실린더 헤드포트 유동 특성 실험 연구 (An Experimental Study of the Flow Characteristics of Cylinder Head Port for Medium-Speed Diesel Engines)

  • 김진원;갈상학
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.790-795
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    • 2001
  • Since the characteristics of combustion and pollutant in Diesel engines were mainly affected by the characteristics of in-cylinder gas flow and fuel spray, an understanding of those was essential to the design of the D.I. Diesel engines. The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since the air resistances in intake and exhaust flow passages, valve lift and valve shape influence greatly to the volumetric efficiency, it is very important to investigate the flow characteristics of intake and exhaust port which develops air motion in the combustion chamber. This paper presents the results of an experimental investigation of steady flow through the various kinds of commercial cylinder head ports, and the development procedures of HHI's H21/32 prototype cylinder head ports.

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열펌프 압축기의 내부 액분사 효과에 대한 수치해석적 연구 (A Numerical Study of Liquid Injection into the Compressor Cylinder of a Heat Pump)

  • 허재경;방광현
    • 설비공학논문집
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    • 제15권5호
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    • pp.397-405
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    • 2003
  • Heat and fluid flow in a compressor into which liquid refrigerant is injected for the purpose of reducing discharge gas temperature in a heat pump system has been numerically studied. A mechanistic approach encompassing liquid jet breakup and droplet evaporation has been performed to investigate the effects of liquid injection on the spacial and temporal variation of the gas temperature and pressure inside the compressor cylinder. Various parameters, such as liquid injection mass, time, duration and droplet size, are considered in the present study to elucidate the flow field inside the compressor. As the injection mass is increased, discharge gas temperature is decreased, while the pressure is increased due to the added mass of the injection. For the injected liquid mass corresponding to 15% of the total vapor mass in the cylinder, the discharge gas temperature drops by 22.4 K. It is observed that the droplet size plays a major role in the evaporation rate of the droplets that determines the degree of the discharge temperature drop.