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충돌분무의 액적 거동에 미치는 비등방성 난류특성의 영향에 대한 수치해석 연구
고권현(G. H. Ko),유홍선(H. S. Ryou) 한국전산유체공학회 2003 한국전산유체공학회지 Vol.8 No.4
It is an aim of this study to perform extensive numerical study for analyzing the anisotropic turbulence effects on spatial and temporal behaviors of droplet for impinging sprays. The turbulence model of Durbin is used for comparisons with the k-E model. The turbulence-induced dispersions of droplets are consider to describe the anisotropy of turbulence effectively and spray/wall interactions are simulated using the model of Lee and Ryou. Present study investigates the overall and the internal structures of impinging diesel sprays such as spray shapes, radius and height of wall sprays, Sauter mean diameter (SMD), local droplet velocity, and local gas velocity and compared the results with experimental data by two adopted turbulence models. When the anisotropy effect of turbulence is included, better predictions for both gas and droplet tangential velocities are obtained, compared to the k-ε model. It is concluded that anisotropic effect of turbulence should be considered for simulating impinging diesel sprays.
댐퍼 위치가 구획문의 유동분포에 미치는 영향에 관한 수치해석 연구
문효준(H.J. Moon),김홍진(H.J Kim),Andrey Burakov,고권현(G.H. Ko),유홍선(H.S. Ryou) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
The pressurized smoke control system is important for fire safety in building because it is directly concerned with egress time of people. Even though the damper plays an essential role in the pressurized smoke control system, the research for a position of damper effects on distribution of air flow at the compartment door is not performed. In this study, numerical simulation using FDS 5.0 was carried out to analyze the effect of the position of damper on flow distribution at the compartment door. To simulate real situation, effects of opening and closing of compartment door was considered. When the damper is on the opposite wall of the compartment door, the back flow to the lobby is large compared to the two other cases of damper position.
수정된 CIP방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구
손소연(S.Y. Son),고권현(G.H. Ko),이성혁(S.H. LEE),유홍선(H.S. Ryou) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. CIP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved CIP method which treats nonlinear term once more comparison with original CIP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original CIP method. The result using improved CIP method shows the better result of the experiments, comparison with result of original CIP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original CIP method.
수정된 CIP 방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구
손소연(S.Y. Son),고권현(G.H. Ko),이성혁(S.H. Lee),유홍선(H.S. Ryou) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.4
Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. ClP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved ClP method which treats nonlinear term once more comparison with original ClP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original ClP method. The result using improved ClP method shows the better result of the experiments, comparison with result of original ClP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original ClP method.
열전달을 수반하는 액적의 퍼짐 현상에 대한 수치해석 연구
손소연(S.Y. SON),고권현(G.H. KO),유홍선(H.S. RYOU) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
Contact angle is significant parameter to simulate droplet spreading after impingement on the wall because it is based on analysis of surface tension that is important term in the momentum equation. In almost numerical approaches, it is implemented in the boundary condition as constant value. However, contact angle has various values as different time and contact line velocities. In this paper, the simulation of droplet spreading on the heated surface is presented and both static contact angle and dynamic contact angle which is function of contact line velocities and time are considered as boundary condition to calculate surface tension. Newly modeled function which is obtained the experiment of single droplet spreading and impingement on the flat bare wall is used for dynamic contact angle. The VOF (Volume of Fluid) method which is one of the most famous interface tracking methods and CSF (Continuum Surface Force) model are used for calculation of interface between two phases. Overall, in the numerical result of droplet spreading and impingement on the heated surface, the heat exchange (flux) is affected by contact angles. Furthermore, this heat exchange affects the dynamics of droplet. The larger Weber number shows larger heat exchange between droplet and surface, larger droplet spreading radius and lower spreading height.