• Title/Summary/Keyword: Combustion model

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Performance Design Techniques for Scramjet Engines with Finite-rate Chemistry Combustion Models (유한화학반응 연소 모델을 고려한 스크램제트 엔진의 성능설계 기법)

  • Kim, Sun-Kyoung;Seo, Bong-Gyun;Kim, Sung-Jin;Sung, Hong-Gye;Byen, Jong-Ryul;Yoon, Hyun-Gull
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.401-405
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    • 2010
  • An efficient performance model for scramjet engines has been proposed for scramjet performance design. In supersonic air intake design, the compression angles of the wedge were determined to maximize the total pressure recovery of the intake based on Oswatisch criterion. Both combustion models of chemical equilibrium and finite-rate chemistry model are implemented, and compared each model with the results by Starkey for Waverider engine configuration. Finally, the performance model of concern has been confirmed by conducting performance analysis with hypothetical mission profile and design conditions.

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Verification and Analysis of Characteristics of Mechanical Pulsation for Combustion Stability Study in a Model Chamber (모형 연소기의 연소 불안정성 연구용 섭동 장치의 기능 검증 및 분석)

  • Min, Yong-Ho;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.28-30
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    • 2012
  • A mechanical pulsator is manufactured for study of combustion instabilities in a model chamber with impinging-jet injectors. Artificial disturbance is generated by the device and thereby, artificial instability can be examined experimentally. A sample F(fuel)-O(dxidizer)-O-F impinging-jet injector is adopted for the test. The model chamber was designed based on the methodologies proposed in the previous work regarding geometrical dimensions and operating conditions. Pressure fluctuation data, which is obtained from the dynamic pressure transducers installed in combustion chamber, is analyzed.

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Application of Weighted Sum of Gray Gases Model with Gray Gas Regrouping for Opposed Flow Flames (대향류화염에서의 회색가스재조합 회색가스가중합법의 적용)

  • Park, Won-Hee;Kim, Tae-Kuk
    • Journal of the Korean Society of Combustion
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    • v.10 no.2
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    • pp.9-17
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    • 2005
  • WSGGM with gray gas regrouping is successfully applied to study the flame structure of opposed flow flames including effect of radiative transfer. The statistical narrow band model is used to obtain the benchmark solutions. Results obtained by using the optically thin model are shown to overestimate the emission and to predict the flame structures inadequately especially for optically thick and low stretch rate flames. Computed results by using the WSGGM with 10 gray gases and SNB model show reasonable agreements with each other, and the required calculation time for the WSGGM is acceptable for engineering applications.

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Numerical Study on Turbulent Nonpremixed Pilot Stabilized Flame using the Transported Probability Density Function Model (수송확률밀도함수 모델을 이용한 난류비예혼합 파일럿 안정화 화염장 해석)

  • Lee, Jeong-Won;Kim, Yong-Mo
    • Journal of the Korean Society of Combustion
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    • v.15 no.4
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    • pp.15-21
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    • 2010
  • The transported probability density function(PDF) model has been applied to simulate the turbulent nonpremixed piloted jet flame. To realistically account for the mixture fraction PDF informations on the turbulent non-premixed jet flame, the present Lagrangian PDF transport approach is based on the joint velocity-composition-turbulence frequency PDF formulation. The fluctuating velocity of stochastic fields is modeled by simplified Langevin model(SLM), turbulence frequency of stochastic fields is modeled by Jayesh-Pope model and effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate the present approach, the numerical results obtained by the joint velocity-composition-turbulence frequency PDF model are compared with experimental data in terms of the unconditional and conditional means of mixture fraction, temperature and species and PDFs.

Transported PDF Model for Turbulent Nonpremixed Flames (수송 확률밀도함수모델을 이용한 비예혼합 난류화염장 해석)

  • Lee, Jeong-Won;Seok, Joon-Ho;Kim, Yong-Mo
    • Journal of the Korean Society of Combustion
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    • v.14 no.2
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    • pp.32-41
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    • 2009
  • The transported probability density function model combined with the consistent finite volume (FV) method has been applied to simulate the turbulent bluff-body reacting flows. To realistically account for the non-isotropic turbulence effects on the turbulent bluff-body reacting flows, the present PDF transport approach is based on the joint velocity- turbulent frequency-composition PDF formulation. The evolution of the fluctuating velocity of a particle is modeled by a simplified Langevin equation and the particle turbulence frequency is represented by the modified Jayesh - Pope model. Effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate this hybrid FV/PDF transport model, the numerical results are compared with experimental data for the turbulent bluff-body reacting flows.

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NUMERICAL ANALYSIS TO DESIGN HIGH TEMPERATURE HEAT EXCHANGER OF BETA TYPE STIRLING ENGINE IN 3-D COMBUSTION FIELD (3차원 연소장에서의 베타 형태의 스털링엔진 고온 열교환기 설계를 위한 수치해석 연구)

  • Kang, S.H.;Kim, H.J.;Chung, D.H.
    • Journal of computational fluids engineering
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    • v.16 no.2
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    • pp.56-61
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    • 2011
  • Numerical study is conducted to design the high temperature heat exchanger of Stirling engine by using the commercial CFD solver, FLUENT. The Fin-tube type of heat exchanger is designed as a reference model by considering the type of engine which is ${\beta}$-configuration. To find the optimal design of heat exchanger in heat transfer capacity numerical calculation is conducted by changing the shape, the number, and material of reference model in three-dimensional combustion field. Adjusted one-way constant velocity of working fluid that is helium is considered as the representative velocity of oscillating flow. The optimal design of heat exchanger considering the heat transfer capability is suggested by using the calculation results.

Computational Simulation to Predict Emissions of a Heat Recovery Steam Generator (가스터빈 열 회수 증기 발생기의 배출 가스 예측 모사 해석)

  • Han, Woojoo;Jang, Jihoon;Lee, Youngjae;Han, Karam;Huh, Kang Y.
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.67-70
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    • 2014
  • We performed computational simulation for a heat recovery steam generator to predict emissions (especially carbon monoxide) and compare the results with experimental data. We used the steady laminar flamelet model(SLFM) which can consider detailed chemical mechanisms. To reduce the number of grid, we simplified the geometry of the whole heat recovery steam generator. In conclusion, the trend of simulation results is good agreement with experimental data.

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Numerical Analysis on Flow and Heat Transfer of Horizontal Firing Boiler (Horizontal Firing Boiler의 열유동 해석)

  • Kim, K.C.;Man, M.H.;Kim, J.K.;Choi, C.R.;Kang, D.W.;Kim, C.N.
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.973-978
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    • 2001
  • Numerical Analysis for liquid fuel combustion of horizontal firing boiler is performed. The mixture-fraction/PDF equilibrium chemistry model is used to predict the combustion of the vaporized fuel. P1 model for radiation effect is used. Superheater, reheater and economizer is modeled using porous with heat sink. Flow and temperature field is investigated, and distribution of thermal $NO_{x}$ and CO is investigated. Computation as the change of excess air and swirling is performed to investigate the change of thermal $NO_{x}$.

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