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회전익 채널내 후류장에 의한 비정상 유동특성에 관한 연구
김윤제,전용렬,Kim, Youn J.,Jeon, Y.-R 한국유체기계학회 1999 한국유체기계학회 논문집 Vol.2 No.4
The characteristic of unsteady flowfields on gas turbine, particularly on a rotor blade surface has been numerically investigated. The unsteady flow in a rotor blade passage as a result of wake/blade interaction is modeled by the inviscid flow approach, and solved by Euler equations using a time accurate marching scheme. Unsteady flow in the blade passage is induced by periodically moving a wake model across the passage inlet. The wake model used in this study is the Gaussian wate model in which the wake flow is assumed to be parallel with uniform static pressure and uniform relative total enthalpy. Numerical results show that for the case of Ps/Pr=1.5, the velocity and pressure distribution on the blade surfaces have much more complex profiles than for the case of Ps/Pr=1.0.
상사해법을 이용한 쐐기형 물체 주위의 미세 극성유체 유동 특성에 관한 연구
김윤제,Kim, Youn J. 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.8
A similarity solution of a steady laminar flow of micropolar fluids past wedges has been studied. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equations. Numerical solutions of the equations are then obtained using the fourth-order Runge-Kutta method and the distribution of velocity, micro-rotation, shear and couple stress across the boundary layer are obtained. These results are compared with the corresponding flow problems for Newtonian fluid past wedges with various wedge angles. Numerical results show that, keeping ${\beta}$ constant, the skin friction coefficient is lower for a micropolar fluid, as compared to a Newtonian fluid. For the case of constant material parameter K, however, the velocity distribution for a micropolar fluid is higher than that of a Newtonian fluid.
[디젤엔진부문] 틈새 간극이 Roots형 과급기 성능에 미치는 영향
김윤제(Youn J. Kim),최근우(G.W. Choi) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The effects of clearance on the performance of Roots-type supercharger is investigated numerically. A computer program is developed for creation of a new lobe shape. Numerical analyses are preformed for the flowfields in the pocket volumes formed by various lobe shapes. The governing equations for the two-dimensional, turbulent, operational processes in the housing are discretized by the finite volume method that insures the conservative characteristics to be satisfied in the calculation domain, and they are solved by a modified SIMPLE algorithm. Numerical results show that the effect of clearance between lobe and stator on the leakage flow rate is smaller than that of between two lobes. Results also show that Cassini lobes have smaller the leak flow rate than the other lobe shapes.
후류장에 의한 가스터빈 회전익 통로내 비정상 유동의 수치해석적 연구
김윤제(Youn J. Kim),전용렬(Y. R. Jeon) 한국유체기계학회 1998 유체기계 연구개발 발표회 논문집 Vol.- No.-
The effects of unsteady flow on gas turbine, particularly on a rotor blade surface are numerically investigated. The unsteady flow in a rotor blade passage as a result of wake/blade interaction is modeled by the inviscid flow approach, and solved by the Euler equations using a time accurate marching scheme. Numerical results show that for the case of Ps/Pr=1.5, the velocity and pressure distribution on the blade surfaces have much more complex profiles than those of Ps/Pr=1.0.