• 제목/요약/키워드: Spray model

검색결과 498건 처리시간 0.028초

연료분사계 변수의 변화에 따른 커먼레일 디젤엔진의 분무특성에 관한 수치적 분석 (A Numerical Analysis on the Spray Characteristics at Different Injection System Parameters in a Common-rail Diesel Engine)

  • 이석영;전충환
    • 한국분무공학회지
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    • 제15권1호
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    • pp.8-16
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    • 2010
  • This paper present the diesel spray characteristics at different injection system parameters in a HSDI diesel engine. The spray characteristics was calculated by the coupled simulation of fuel injection system model and three-dimensional KIVA-3V code with TAB spray model. The relevant injection parameters are accumulator volume, control chamber initial volume, control orifice diameter, needle valve diameter and nozzle chamber initial volume, etc. Parametric investigation with respect to twelve relevant injection parameters showed that there was a significant advantage in varying control chamber initial volume, control chamber orifice diameter, and nozzle chamber orifice diameter with respect to effect the SMD and fuel injection speed. Consequently, in order to design the fuel injection system for spray characteristics, it seems reasonable to suppose to be optimized the fuel injection system.

관창의 유동특성에 관한 연구 (A Study on the Flow Characteristics of the Spray Nozzle)

  • 이동명
    • 한국화재소방학회논문지
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    • 제17권3호
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    • pp.55-60
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    • 2003
  • 본 연구에서는 관창의 유동특성예측을 위한 해석이론을 정립하고 수치해석으로부터 방수량과 방수형태를 예측하였다. 예측 데이터로부터 관창의 방수형태가 노즐과 니들의 위치에 따라 결정됨을 알 수 있었고, 관창의 유동특성은 노즐과 니들의 형상에 따라 그 특성이 결정됨을 알 수 있었다. 관창의 유동특성과 예측 데이터로부터 화재진압의 효율성을 극대화할 수 있는 새로운 관창의 모델이 제시되었다. 본 연구의 결과가 새로운 모델의 관창을 개발하는데 필요한 자료로 활용할 수 있을 것으로 보며, 또한 관창의 원천기술 확보, 동종업계의 기술력 파급효과 증대 및 소방분야의 기술개발 활성화 등에 이바지하고 자 한다.

흡기 가습에 의한 압축 착화엔진 실린더 내 디젤 연료 분무 특성 예측 (Prediction of Diesel Fuel Spray Characteristics in Compression Ignition Engine Cylinder by Intake Humidification)

  • 민세훈;서현규
    • 한국분무공학회지
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    • 제23권1호
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    • pp.30-35
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    • 2018
  • The objective of this study is to predict numerically the effect of intake humidification on the injected diesel fuel spray characteristics in a compression ignition engine. In this work, Wave model and Ducowicz model were applied as the break-up model and evaporation model, respectively. The amount of water vapor for the humidification was changed from 0% to 30% of injected fuel mass. The number of applied meshes was generated from 49,000 to 110,000. At the same time, the results of this work were compared in terms of spray tip penetration, SMD and equivalence ratio distributions. It was found that the cylinder temperature and cylinder pressure were decreased with increasing water vapor mass by vaporization latent heat and specific heat, however, the difference was very small. So, the spray tip penetration was not different by water vapor mass. Also, higher equivalence ratio distributions were observed with increasing water vapor mass by the improvement of fuel atomization.

벽면에 충돌하는 분무의 미립화에 관한 수치적 모델 (A Numerical Model for Atomization of an Impinging Spray on the Wall)

  • 조미옥;허강열
    • 한국분무공학회지
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    • 제2권1호
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    • pp.36-45
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    • 1997
  • A spray-wall impingement model for fuel sprays is proposed and implemented as a module into the KIVA-POSTECH code. The model is based on the single droplet experiments. The droplet behaviors after impingement are determined from experimental correlations. Different behaviors of impinged droplets depend on the wall temperature and the critical temperature of the fuel. Fuel film formation is taken into account so that the model can be applicable to any wall temperature and injection conditions. Computational results on a normal and on inclined wall are in good agreement for the spray shape and penetration. More validation against experiments and development of the heat transfer model are needed for further improvement.

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가스터빈 연소기 내 운전조건 변화에 따른 분무연소 특성 연구 (Study on Characteristics of Spray Combustion for Various Operation Conditions in a Gas Turbine Combustor)

  • 조상필;김호영;박심수
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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    • pp.3-10
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    • 2002
  • In this work, numerical parametric studies on spray combustion have been conducted. In simulation of turbulence, RNG ${\kappa}-{\varepsilon}model$ is adopted. Initial spray distribution is specified by Rosin-Rammler distribution function. Eddy break-up model is adopted as a combustion model. The parameters considered are inlet air temperature, swirl number, and SMD. With higher inlet air temperature, the axial velocities are increased and penetration of primary jet is stronger than that of lower inlet air temperature and temperature at the exit of combustor is more uniform. Combustion efficiency is improved with high inlet air temperature. The effect of swirl number on flow field is not significant. It affect only recirculation zone. So temperature at upstream of combustor is influenced. Combustion efficiency deteriorate as SMD of fuel spray increase.

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분사칼럼식 직접접촉열교환기의 열전달특성에 관한 수치적 연구 (A Numerical Study on Heat Transfer Characteristics in a Spray Column Direct Contact Heat Exchanger)

  • 강용혁;김남진;김종보
    • 설비공학논문집
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    • 제12권8호
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    • pp.735-744
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    • 2000
  • In order to define the heat transfer characteristics in a spray column direct contact heat exchanger, the development of a multidimensional numerical model and computational algorithm is essential to analyze the inherent multidimensional characteristics of a direct contact heat exchanger. In the present study, it has been carried out numerical calculations using a two-dimensional model for operation of a direct contact heat exchanger. Such operational and system parameters as the injection velocity, void fraction, aspect ratio and injection temperature of each fluid are examined thoroughly to assess their influence on the performance of a spray column. Analyzed results has shown that our two-dimensional model predicts the heat transfer phenomena well in a spray column.

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직접분사엔진의 분사압력 변화에 따른 유동장 및 분무특성에 대한 수치해석적 연구 (Numerical Simulations of the Injection Pressure Effect on the Flow Fields and the Spray Characteristics in Direct Injection Engine)

  • 양희천;정연태;유홍선
    • 대한기계학회논문집
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    • 제17권9호
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    • pp.2339-2358
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    • 1993
  • Since the rate and completeness of combustion in direct injection engines were controlled by the characteristics of gas flow fields and sprays, an understanding of those was essential to the design of the direct injection engines. In this study the numerical simulations of injection pressure effects on the characteristics of gas flow fields and sprays were preformed using the spray model that could predict the interactions between gas fields and spray droplets. The governing equations were discretized by the finite volume method and the modified k-.epsilon. model which included the compressibility effects due to the compression/expansion of piston was used. The results of the numerical calculation of the spray characteristics in the quiescent environment were compared with the experimental data. There were good agreements between the results of calculation and the experimental data, except in the early stages of the spray. In the motoring condition, the results showed that a substantial air entrainment into the spray volume was emerged and hence the squish motion was relatively unimportant during the fuel injection periods. It was found that as the injection pressure increased, the evaporation rate of droplets was decreased due to the narrow width of spray and the increased number of droplets impinged on the bottom of the piston bowl.

액적변동을 고려한 액체로켓의 연소실 내 비정상 분무연소 해석 (Spray Combustion Analysis for Unsteady State in Combustion Chamber of Liquid Rocket Engine Considering Droplet Fluctuation)

  • 정대권;노태성
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2006년도 제27회 추계학술대회논문집
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    • pp.175-178
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    • 2006
  • 인젝터의 특성을 고려한 분무연소 현상을 해석하기 위하여 연소실에 주입되는 연료와 산화제의 액적에 변동을 가해 연소실내 분무연소 현상을 수치적으로 해석하였다. 2차원 비정상 상태의 유동장을 QUICK Scheme과 SIMPLER Algorithm을 사용하여 계산하였고, 분무모델로는 DSF 모델과 Euler-Lagrange방법을 사용하였다. 연료와 산화제의 액적 변동은 사인 함수를 이용하여 모델링 하였고, 액적과 가스상의 커플효과와 가스상과 증발된 기체상의 커플효과는 PSIC 모델을 사용하여 계산하였다.

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Experimental Investigation and Modeling of the Specific Enthalpy Distribution in a Spray Cone

  • Ellendt, N.;Uhlenwinkel, V.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.58-59
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    • 2006
  • In Spray Forming, specific enthalpy is a key parameter in the deposition process as it influences the thermal condition of the impinging droplets as well as that of the deposit surface. An empirical model for the distribution of specific enthalpy in the spray cone was developed as an easy to handle alternative to numerical models with which the descriptive partial differential equations are solved numerically. The model results were compared with the experimental data to validate its applicability.

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고압 상태에서의 연료 분무의 증발 및 연소 특성 해석 (Numerical Studies on Vaporization Characterization and Combustion Processes in High-Pressure Fuel Sprays)

  • 문윤완;김용모;김세원;김주연;윤인용
    • 한국분무공학회지
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    • 제3권3호
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    • pp.49-59
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    • 1998
  • The vaporization characteristics and spray combustion processes in the high-pressure environment are numerically investigated. This study employ the high-pressure vaporization model together with the state-of-art spray submodels. The present high-pressure vaporization model can account for transient liquid heating, circulation effect inside the droplet forced convection, Stefan flow effect, real gas effect and ambient gas solubility in the liquid droplets. Computations are carried out for the evaporating sprays, the evaporating and burning sprays, and the spray combustion processes of the turbocharged diesel engine. Numerical results indicate that the high-pressure effects are quite crucial for simulating the spray combustion processes including vaporization, spray dynamics, combustion, and pollutant formation.

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