비예혼합 난류 화염의 난류와 복사의 상호작용 및 매연 생성에 대한 수치적 연구

우민호(Mino Woo),김태훈(Taehoon Kim),김용모(Yongmo Kim),김후중(Hoo-Joong Kim) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38

Numerical simulation results are presented for axisymmetric, nonluminous turbulent confined jet flame. The turbulence-chemistry interaction is represented by the laminar flamelet model together with the presumed PDF approach which easily implements the variable thermo-chemical properties and the complex soot source terms from the information of detailed chemical kinetic model. The radiative transfer equation is solved using spherical harmonic P-1 approximation. In the present study, the Turbulence-Radiation interaction(TRI) is taken into account in context with the flamelet concept. The soot formation and oxidation processes are modeled by the two variable approach which realistically accounts for soot nucleation, coagulation, surface growth and oxidation. The numerical and physical models used in this study successfully predict the essential features of the combustion processes and soot formation characteristics in the turbulent non-premixed flame field.

일반 공기 및 순산소 연소 조건에서 Fuel-NO<SUB>x</SUB> 생성 특성의 비교

우민호(Mino Woo),박권하(Kweon Ha Park),최병철(Byung Chul Choi) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.5

10 %의 암모니아가 첨가된 메탄 연료의 비예혼합 확산화염에서, 산소/이산화탄소 및 산소/질소의 산화제 내에 산소 비율의 변화에 따른 질소산화물(NO_x)의 생성 특성을 실험 및 수치해석적으로 조사하였다. 동축류 제트 화염의 실험에서, 산소/이산화탄소의 산화제인 경우, 측정된 NO_x 은 산소비율의 증가에 따라 약간 증가하는 경향을 보였다. 반면에, 산소/질소의 산화제인 경우, NO_x 은 0.7의 산소 비율에서 최대로 측정되었으며, 산소 비율에 따라 비단조적인 경향을 보였다. 결과적으로, 암모니아가 첨가된 메탄 화염에서 배출되는 NO_x 는 일반 공기의 조건보다 순산소 연소 조건의 경우가 더 크게 측정되었다. 한편, 다양한 산화제의 조건에 대하여 NO_x 생성 특성을 분석하기 위해서, 동일한 화학반응 메커니즘을 적용하여 1차원 및 2차원의 수치해석을 수행하였다. 그 결과, 산소/질소의 산화제에서 2차원의 수치해석 결과가 실험적으로 측정된 NO_x 의 배출 특성을 비교적 잘 예측하였다. Nitric oxide (NO_x) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the NO_x emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the NO_x emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the NO_x emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of NO_x formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured NO_x emissions.

1차원 Plug Flow Reactor Model을 이용한 금속품 후처리 장치의 촉매 산화 반응특성에 대한 수치 모델링

우민호(Mino Woo),김구환(Kuhwan Kim),이정민(Jeongmin Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Various type of diesel exhaust after treatment applications has been recently researched and characterized. The present paper focuses on catalytic oxidation characteristics of the Diesel Oxidation Catalyst constructed by metal foam substrates. The potential advantages of using metal foams as DOC substrates area mainly related to enhanced heat and mass transfer which offer the possibility to operate efficiently at higher space velocities compared to traditional flowthrough substrates. Metal foam based after-treatment systems has different characteristics from earlier systems such as monolith type reactor. Previous DOC models are based on general LHHW type reaction. There are several limitations to adjust LHHW model on foam-type reactor because LHHW model was developed with assumption that mass and heat of each gas phase and solid phase are transported in channel flow. Some different characteristics are exist in other types of reactor such as foam type or packed bed type. And using detailed kinetics, the model can predict more correctly but the calculation time increase dramatically. So the LHHW model revised to validate more correctly. In this paper, we focus on making basic transfer and reaction rate using the model based on 1D plug flow type rather than full CFD model. First we obtain each reaction parameter from binary reaction data, and adjust the model to real condition.

마이크로리엑터를 이용한 금속폼 기반 DOC에서의 촉매 화학 반응에 대한 연구

우민호(Mino Woo),김구환(Kuhwan Kim),김후중(Hoojoong Kim),이정민(Jeongmin Lee),이병하(Byungha Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

An alternative metal foam substrate for diesel exhaust after treatment applications has been recently researched and characterized. The present paper focuses on the potential of the metal foam technology as an efficient DOC substrates on real conditions. The target platform is a mid-size passenger car and the methodology includes both modeling and experiments. The lab-scale reactor called Micro-Reactor system has been provided to analyze binary reaction and complex reaction. To analyze metal foam substrate, the alternative model which reaction rate and transfer coefficients are not based on early honeycomb monolith is required. Based on experimental result, the reaction rate and activation energy of each binary reaction are established, and the light-off results of the real gas composition are compared to experimental conversion data. The main binary reactions of DOC such as CO, HC and NO are experimented to establish the reaction kinetics. And the contribution and limitation of this binary reactions are studied in the calculation and experimentation of real gas condition. In this paper, we focus on making basic transfer and reaction rate using the model based on 1D plug flow type rather than full CFD model. And the model use CHEMKIN library to obtain gas properties of chemical species.

직접적분법을 이용한 C₂H₄/Air 비예혼합 난류연소의 매연생성 모델링

김태훈(Taehoon Kim),우민호(Mino Woo),김용모(Yongmo Kim) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40

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.

모멘트 직접적분법을 이용한 비예혼합 난류화염장의 매연입자 생성에 대한 수치모델링

김태훈(Taehoon Kim),우민호(Mino Woo),김용모(Yongmo Kim) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39

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 and requires the relatively low computational cost. Soot inception and subsequent aggregation, surface growth and oxidation are described through a population balance model solved with the Direct quadrature method of moments. This approach is 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 which easily implements the variable thermo-chemical properties and the radiative transfer equation is considered using spherical harmonic P-1 approximation.

C₂H₄/Air 비예혼합 난류화염의 매연생성 모델링

김태훈(Taehoon Kim),우민호(Mino Woo),김용모(Yongmo Kim) 한국연소학회 2010 한국연소학회지 Vol.15 No.4

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.

금속폼 필터의 3차원 유동해석프로그램 개발에 관한 연구

오준석(Junseok Oh),이정민(Jeongmin Lee),김구환(Kuhwan Kim),우민호(Mino Woo) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

DPF systems have been adopted due to the reinforcement of the emission regulation over the world. This easy studies a application of 3D CFD program using metal foam filter. In the result, it is verified that soot filtration and pressure drop over metal foam filters can be predictable with 3D CFD program