• 제목/요약/키워드: DQMOM

검색결과 7건 처리시간 0.042초

$C_2H_4$/Air 비예혼합 난류화염의 매연생성 모델링 (Numerical Modeling of Soot Formation in $C_2H_4$/Air Turbulent Non-premixed Flames)

  • 김태훈;우민호;김용모
    • 한국연소학회지
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    • 제15권4호
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    • pp.22-28
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    • 2010
  • The Direct Quadrature Method of Moments (DQMOM) has been presented for the solution of population balance equation in the wide range of the multi-phase flows. This method has the inherently interesting features which can be easily applied to the multi-inner variable equation. In addition, DQMOM is capable of easily coupling the gas phase with the discrete phases while it requires the relatively low computational cost. Soot inception, subsequent aggregation, surface growth and oxidation are described through a population balance model solved with the DQMOM for soot formation. This approach is also able to represent the evolution of the soot particle size distribution. The turbulence-chemistry interaction is represented by the laminar flamelet model together with the presumed PDF approach and the spherical harmonic P-1 approximation is adopted to account for the radiative heat transfer.

난류 Pilot 비예혼합 화염장의 상세구조 해석 (Numerical Investigations of Turbulent Piloted Non-Premixed Flames)

  • 이정원;전상태;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.185-186
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    • 2014
  • The multi-environment probability density function model has been applied to simulate the turbulent stratified premixed flames. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. The IEM mixing model is employed to represent the mixing process and the chemical mechanism is based on Gri 3.0 mechanism. Numerical results obtained in this study are precisely compared with experimental data in terms of unconditional and conditional means for scalar fields and velocity fields.

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궤도결정을 위한 비선형 필터 (Nonlinear Filter for Orbit Determination)

  • 윤장호
    • 항공우주시스템공학회지
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    • 제10권1호
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    • pp.21-28
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    • 2016
  • Orbit determination problems have been interest of many researchers for long time. Due to the high nonlinearity of the equation of motion and the measurement model, it is necessary to linearize the both equations. To avoid linearization, the filter based on Fokker-Planck equation is designed. with the extended Kalman filter update mechanism, in which the associated Fokker-Planck equation was solved efficiently and accurately via discrete quadrature and the measurement update was done through the extended Kalman filter update mechanism. This filter based on the DQMOM and the EKF update is applied to the orbit determination problem with appropriate modification to mitigate the filter smugness. Unlike the extended Kalman filter, the hybrid filter based on the DQMOM and the EKF update does not require the burdensome evaluation of the Jacobian matrix and Gaussian assumption for the system, and can still provide more accurate estimations of the state than those of the extended Kalman filter especially when measurements are sparse. Simulation results indicate that the advantages of the hybrid filter based on the DQMOM and the EKF update make it a promising alternative to the extended Kalman filter for orbit estimation problems.

난류 성층 예혼합 화염장의 상세구조 해석 (Numerical Investigations of Turbulent Stratified Premixed Flames)

  • 전상태;김남수;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.183-184
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    • 2014
  • The multi-environment probability density function model has been applied to simulate the turbulent stratified premixed flames. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. Computations are made for the non-swirling turbulent stratified premixed flames including SWB1, SWB5 and SWB9. The numerical results obtained in this study are precisely compared with experimental data in terms of axial velocity, unconditional means and conditional means for scalar field including temperature and species mass fraction.

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난류 비예혼합 및 부분예혼합 화염장에서 매연입자의 생성특성 해석 (Numerical Studies on Soot Formation Characteristics of Turbulent Non-premixed and Partially Premixed Flames)

  • 김태훈;이정원;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.141-143
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    • 2012
  • The present study is aiming at numerically analyze the soot formation processes coupled with gas reaction mechanism in turbulent non-premixed and partially premixed flames. In order to realistically represent turbulence-chemistry interactions with detailed chemical kinetics and soot formation behaviour related to the turbulent non-premixed and partially premixed flames, the transient flamelet[1] and flamelet based level-set approach[2] are coupled with soot formation based on the two equation model [3] and DQMOM (Direct Quadrature Method of Moment)[4].

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무향변환을 이용한 비선형 필터에 대한 연구 (Study on Nonlinear Filter Using Unscented Transformation Update)

  • 윤장호
    • 항공우주시스템공학회지
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    • 제10권1호
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    • pp.15-20
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    • 2016
  • The optimal estimation of a general continuous-discrete system can be achieved through the solution of the Fokker-Planck equation and the Bayesian update. Due the high nonlinearity of the equation of motion of the system and the measurement model, it is necessary to linearize the both equation. To avoid linearization, the filter based on Fokker-Planck equation is designed. with the unscented transformation update mechanism, in which the associated Fokker-Planck equation was solved efficiently and accurately via discrete quadrature and the measurement update was done through the unscented transformation update mechanism. This filter based on the Direct Quadrature Moment of Method(DQMOM) and the unscented transformation update is applied to the bearing only target tracking problem. The proposed filter can still provide more accurate estimation of the state than those of the extended Kalman filter especially when measurements are sparse. Simulation results indicate that the advantages of the proposed filter based on the DQMOM and the unscented transformation update make it a promising alternative to the extended Kalman filter.

MILD 연소환경에서의 난류 CH4/H2 난류 화염장 해석 (Numerical Investigations of Turbulent CH4/H2 flames under MILD combustion condition)

  • 전상태;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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    • pp.267-268
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    • 2015
  • The multi-environment probability density function model has been applied to simulate the turbulent $CH_4/H_2$ flames under MILD conditions. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. The IEM model represents the micromixing process. The numerical results obtained in this study are precisely compared with experimental data in terms of unconditional means and conditional means for scalar field including temperature and species mass fraction.

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