• Title/Summary/Keyword: In-Cylinder Gas Flow

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

  • 이창식;전문수;김우경;최수천
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.8
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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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A Study on the Improvement of In-Cylinder Flow Motion in the Natural Gas Engine (천연가스엔진의 실린더내 흡기유동개선에 관한 연구)

  • Seo, Seung-U;Jeong, Dong-Su;O, Seung-Muk;Choe, Gyo-Nam
    • 연구논문집
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    • s.23
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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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    • v.15 no.1
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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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Characteristics of Tumble Flow in Cylinder of 4 Valve Gasoline Engine by Using Particle Tracking Method (입자 추적법을 이용한 4 밸브 가솔린 기관의 실린더 내 텀블 유동 특성)

  • Lee, Chang-sik;Chon, Mun-soo;Chung, Sung-hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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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.

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

  • Jeong, D.S.;Suh, S.W.;Oh, S.M.;Uhm, J.H.;Chang, Y.J.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.3
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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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A study on the Internal Flow Analysis of Gas Cylinder Cabinet for Specialty Gas of Semiconductor (반도체용 특수가스 공급을 위한 가스캐비닛 내부 유동해석에 관한 연구)

  • Kim, Jung-Duck;Han, Seung-A;Yang, Won-Baek;Rhim, Jong-Guk
    • Journal of the Korean Institute of Gas
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    • v.24 no.5
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    • pp.74-81
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    • 2020
  • In general, when manufacturing a semiconductor, a number of hazardous and dangerous substances such as flammability, toxic, and corrosiveness are used. In particular, semiconductors are manufactured using specialty gas in processes such as CVD and etching. The specialty gas is filled in a container in the state of compressed or liquefied gas, and a gas cylinder cabinet is used as a facility for supplying this specialty gas to the semiconductor manufacturing process. When a accident occurs in the gas supply system, gas is released through a pressure release device installed in the gas cylinder to secure the safety of the supply system. In this case, the gas released inside the gas cabinet, there is a risk of leaking to the outside. After that, by analyzing the gas flow in the gas cabinet, it is intended to identify the risk associated with leak and to provide measures to prevent accidents.

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

  • KIM, Kyong-Hyon;KONG, Kyeong-Ju
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.56 no.3
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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.

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

  • Park, Gyung-Do;Park, Jong-Chun;Kim, Kyung-Mi
    • Journal of Ocean Engineering and Technology
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    • v.28 no.4
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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.

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

  • Kim, Jin-Won;Ghal, Sang-Hak
    • Proceedings of the KSME Conference
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    • 2001.06d
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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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A Numerical Study of Liquid Injection into the Compressor Cylinder of a Heat Pump (열펌프 압축기의 내부 액분사 효과에 대한 수치해석적 연구)

  • 허재경;방광현
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.5
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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.