• Title/Summary/Keyword: Vaporization model

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Validation of Hybrid Breakup Model and Vaporization Model for Analysis of GDI Spray Behavior (GDI 분무거동 해석을 위한 혼합분열모델 및 증발모델의 검증)

  • Shim, Young-Sam;Choi, Gyung-Min;Kim, Duck-Jool
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.6
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    • pp.187-194
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    • 2005
  • The objective of this study is to validate the hybrid breakup model and the vaporization model for GDI spray analysis at vaporization and non-vaporization conditions. The atomization process is modeled by using hybrid breakup model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model. The vaporization process is modeled by using modified Abramzon & Sirignano model. The exciplex fluorescence method was used for comparing the calculated results with the experimental ones. The experiment and the calculation were performed at the ambient pressures of 0.1 MPa, 0.5 MPa and 1.0 MPa and the ambient temperature of 293K and 473K.

The Numerical Study on Breakup and Vaporization Process of GDI Spray under High-Temperature and High-Pressure Conditions (고온.고압의 분위기 조건에서 GDI 분무의 분열 및 증발과정에 대한 수치적 연구)

  • 심영삼;황순철;김덕줄
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.3
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    • pp.44-50
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    • 2004
  • The purpose of this study is to improve the prediction ability of the atomization and vaporization processes of GDI spray under high-pressure and high-temperature conditions. Several models have been introduced and compared. The atomization process was modeled using hybrid breakup model that is composed of Conical Sheet Disintegration (CSD) model and Aerodynamically Progressed TAB(APTAB) model. The vaporization process was modeled using Spalding model, modified Spalding model and Abramzon & Sirignano model. Exciplex fluorescence method was used for comparing the calculated with the experimental results. The experiment and calculation were performed at the ambient pressure of 0.5 MPa and 1.0 MPa and the ambient temperature of 473k. Comparison of caldulated and experimental spray characteristics was carried out and Abramzon & Sirignano model and modified Spalding model had the better prediction ability for vaporization process than Spalding model.

Numerical Modeling for Vaporization, Auto-Ignition and Combustion Processes of Dimethyl Ether (DME) Fuel Sprays (DME 연료의 증발, 점화 및 분무연소특성 해석)

  • Yu, Yong-Wook;Lee, Jeong-Won;Kim, Yong-Mo
    • Journal of the Korean Society of Combustion
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    • v.12 no.3
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    • pp.33-39
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    • 2007
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure engine conditions. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model is utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet (RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential feature of ignition and spray combustion processes.

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Numerical Modeling for Auto-Ignition and Combustion Processes of Dimethyl Ether (DME) Fuel Sprays (DME 연료의 점화 및 연소특성 해석)

  • Lee, J.W.;Ryu, L.S.;Kim, Y.M.
    • Journal of ILASS-Korea
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    • v.10 no.4
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    • pp.16-25
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    • 2005
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure engine conditions. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model is utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet(RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential feature of ignition and spray combustion processes.

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Numerical Studies on Combustion Characteristics of Diesel Engines using DME Fuel (DME연료 디젤 엔진에서의 연소특성 해석)

  • Yu, Yong-Wook;Lee, Jeong-Won;Kim, Yong-Mo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.2
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    • pp.143-149
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    • 2008
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and spray combustion processes in DI diesel engine using DME and n-heptane. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model has been utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet (RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Based on numerical results, the detailed discussion has been made for the distinctly different combustion characteristics of DME diesel engine in term of vaporization, ignition delay, pollutant formation, and heat release rate.

Study on Spray Vaporization and Combustion in High Pressure Environment (고압에서의 분무의 증발 및 연소 현상에 관한 연구)

  • Wang, Tae-Joong;Baek, Seung-Wook
    • 한국연소학회:학술대회논문집
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    • 2002.11a
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    • pp.193-207
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    • 2002
  • The present study is mainly motivated to investigate the vaporization, autoignition, and combustion of liquid fuel spray injected into high pressure environment. In order to represent these phenomena realistically, discrete droplet model (DDM) which simulates the spray using finite number of representative droplets was adopted for detailed consideration of the finite rate of uansport between liquid and gas phases. The Eulerian-Lagrangian formulation was used to analyze the two-phase interactions. The high pressure vaporization model was applied using the thermodynamic and phase equilibrium at droplet surface. The high pressure effect as well as high temperature effect was considered in the calculation of liquid and gas properties. The characteristics of spray in high pressure environment were explained by comparison with normal pressure case.

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Numerical Analysis of Spray Behavior and Vaporization Characteristic of GDI Engine Injector Under Ambient Conditions (분위기 조건에 따른 GDI 엔진용 인젝터의 분무거동 및 증발특성에 대한 수치적 해석)

  • Shim, Young-Sam;Hwang, Soon-Chul;Kim, Duck-Jool
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.5
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    • pp.545-552
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    • 2004
  • The purpose of this study is to improve the prediction ability of the atomization and vaporization processes of GDI spray. Several models have been introduced and compared. The atomization process was modeled using hybrid breakup model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed TAB (APTAB) model. The vaporization process was modeled using Spalding model and Abramzon & Sirignano model. Exciplex fluorescence method was used for comparing calculated with experimental results. The experiment and computation were performed at the ambient pressure of 0.1 MPa, 0.5 MPa and 1.0 MPa and the ambient temperature of 293k and 473k. Comparison of calculated and experimental spray characteristics was carried out and the calculated results of GDI spray showed good agreement with experimental results.

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

  • Moon, Y.W.;Kim, Y.M.;Kim, S.W.;Kim, J.Y.;Yoon, I.Y.
    • Journal of ILASS-Korea
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    • v.3 no.3
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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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Numerical Studies on the Combustion Characteristics and Pollutant Formation for the DME Fueled Diesel Engine (DME 연료 디젤엔진의 연소 및 공해물질 배출 특성 해석)

  • Yu, Yong-Wook;Lee, Jeong-Won;Kim, Yong-Mo
    • Journal of ILASS-Korea
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    • v.13 no.1
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    • pp.28-33
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    • 2008
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure diesel engines. In order to realistically simulate the dimethyl ether (DME) fueled diesel engine, the high pressure vaporization model is utilized and the interaction between turbulence and chemistry is treated by employing the Representative Interactive Flamelet (RIF) model. The detailed chemisty consisted of 336 elementary reaction steps and 78 species is used for DME/air reaction. Numerical results indicate that the RIF model with high pressure vaporization model successfully predicts the essential feature of the combustion processes and pollutants formations in the DME fueled diesel engines.

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MOLTEN SALT VAPORIZATION DURING ELECTROLYTIC REDUCTION

  • Hur, Jin-Mok;Jeong, Sang-Moon;Lee, Han-Soo
    • Nuclear Engineering and Technology
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    • v.42 no.1
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    • pp.73-78
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    • 2010
  • The suppression of molten salt vaporization is one of the key technical issues in the electrolytic reduction process developed for recycling spent nuclear fuel from light-water reactors Since the Hertz-Langmuir relation previously applied to molten salt vaporization is valid only for vaporization into a vacuum, a diffusion model was derived to quantitatively assess the vaporization of LiCl, $Li_2O$ and Li from an electrolytic reducer operating under atmospheric pressure. Vaporization rates as a function of operation variables were calculated and shown to be in reasonable agreement with the experimental data obtained from thermogravimetry.