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DES를 이용한 초음속 유동내 수직 연료분사 유동의 비정상 3차원 해석
원수희(S.H. Won),문성영(S.Y. Moon),정인석(I.S Jeung),최정열(J.Y. Choi) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
Unsteady three-dimensional flowfields generated by transverse fuel injection into a supersonic mainstream are simulated with a DES turbulence model. Comparisons are made with experimental results in term of the temporal eddy position and eddy formation frequency. The vorticity field around the jet exit is also analyzed to understand the formation mechanism of the jet vortical structures. Results indicate that the DES model correctly predicts the convection characteristics of the large scale eddies. However, it is also observed that the numerical results slightly overpredict the eddy formation frequency. The jet vortical structures are developed from the competing vortices in the recirculation region of upstream boundary.
효율적인 상세 반응 기구 해석을 위한 민감도 해석 기반의 부분 음해법
강기하(K.-H. Kang),문성영(S.-Y. Moon),노진현(J.-H. Noh),원수희(S.-H. Won),최정열(J.-Y. Choi) 한국연소학회 2008 한국연소학회지 Vol.13 No.1
A partly implicit/quasi-explicit method is introduced for the solution of detailed chemical kinetics with stiff source terms based on the standard fourth-order Runge-Kutta scheme. Present method solves implicitly only the stiff reaction rate equations, whereas the others explicitly. The stiff equations are selected based on the survey of the chemical Jaconian matrix and its Eigenvalues. As an application of the present method constant pressure combustion was analyzed by a detailed mechanism of hydrogen-air combustion with NOx chemistry. The sensitivity analysis reveals that only the 4 species in NOx chemistry has strong stiffness and should be solved implicitly among the 13 species. The implicit solution of the 4 species successfully predicts the entire process with same accuracy and efficiency at half the price.
초음속 유동장에서 기저 유동의 Detached Eddy Simulation
신재렬(J.R. Shin),원수희(S.H. Won),최정열(J.Y. Choi) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
Detached Eddy Simulation (DES) is applied to an axisymmetric base flow at supersonic mainstream. DES is a hybrid approach to modeling turbulence that combines the best features of the Reynolds-averaged Navier-Stokes (RANS) and large-eddy simulation (LES) approaches. In the Reynolds-averaged mode, the model is currently based on either the Spalart-Allmaras (S-A) turbulence model. In the large eddy simulation mode, it is based on the Smagorinski subgrid scale model. Accurate predictions of the base flowfield and base pressure are successfully achieved by using the DES methodology with less computational cost than that of pure LES and monotone integrated large-eddy simulation (MILES) approaches. The DES accurately resolves the physics of unsteady turbulent motions, such as shear layer rollup, large-eddy motions in the downstream region, small-eddy motions inside the recirculating region. Comparison of the results shows that it is necessary to resolve approaching boundary layers and free shear-layer velocity profiles from the base edge correctly for the accurate prediction of base flows. The consideration of an empirical constant CDES for a compressible flow analysis may suggest that the optimal value of empirical constant CDES may be larger in the flows with strong compressibility than in incompressible flows.
스크램제트 엔진의 난류 연소 및 탄화수소 연료 연구 및 방향
최정열(J.-Y. Choi),Bernard Parent,원수희(S.-H. Won),신재렬(S.-H. Lee) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.11
본 논문에서는 그동안 부산대학교 연소추진연구실에서 진행되어 온 스크램제트 엔진 내의 초음속 연료 공기 혼합 및 난류 연소 연구 결과에 대한 소개가 이루질 것이다. 아울러 실용 스크램제트 엔진에서 이용되는 초임계 탄화 수소 연료 연소의 특징과 수치적 모델링 기법에 대하여 소개가 잇을 것이다. Present paper introduces the research activities on fuel-air mixing and combustion of supersonic turbulent flows in scramjet combustor carried out in Aerospace Combustion and Propulsion Laboratory of the department of Aerospace Engineering of the Pusan national University. Also, an introduction will be given to the characteristics of the supercritical hydrocarbon fuel combustion in a practical scramjet engine and its numerical modeling approaches.