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박영민(Y.M. Park),정진덕(J.D. Chung),이해창(H.C. Lee) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
The recent development of CFD technologies and computing resources enables high fidelity aircraft analysis and designs in even conceptual and preliminary design process. More and more, these high fidelity analysis are replacing the high cost wind tunnel tests and contributes to the reduction of entire aircraft design period. In the present paper, examples of CFD applications in KARI(Korea Aerospace Research Institute) are introduced especially for fixed wing aircraft such as turboprop. In KARI, most of CFD processes are mainly used for analysis and design of aircraft. The most basic approaches is for the design of two dimensional airfoil and high lift devices using Navier-Stokes solver. For the three dimensional wing analysis such as wing planform study, high lift device, Navier-Stokes simulations are also commonly used for low and high speed aerodynamic analysis. In order to analyze the effect of rotating propeller effect, unsteady Navier-Stokes simulations using sliding mesh technique are used for the relative motion. In the present paper, various applications of CFD in KARI for fixed wing aircraft design are introduced from two-dimensional high lift device design to rotating propeller effect including high lift device.
유동분배판에 의한 원통-다관형 열교환기의 성능 특성에 관한수치해석적 연구 전열특성(Ⅱ)
박영민(Y.M. Park),이태호(T.H. Lee),정희택(H.T. Chung),김형범(H.B. Kim) 한국전산유체공학회 2016 한국전산유체공학회지 Vol.21 No.4
In the previous study, it is proved by numerical simulation that the baffle shaped as the porous plate installed in the inlet chambers improves the redistribution of the flow injecting to the tube bundles. In the present study, numerical simulation has been performed to investigate the effects of the flow distributors on the thermal characteristics of the shell and tube heat exchangers. The flow fields have been analysed by the three-dimensional Navier-Stokes solvers including the thermal conditions on the shell sides. The numerical results showed that the presence of the baffles improves the redistribution of the heat transfer to the tube bundles though the overall performance drop slightly on the present flow conditions.
3 레벨 인버터를 이용한 유도 전동기의 직접 토크 제어
박영민(Y.M. Park),이세현(S.H. Lee),윤재학(J.H. Yun),박영우(Y.W. Park),김남해(N.H. Kim),이교범(K.B. Lee),송중호(J.H Song) 전력전자학회 1999 전력전자학술대회 논문집 Vol.1999 No.7
In this paper a Direct Torque Control(DTC) scheme for PWM three level inverter-fed induction motor drives, is presented and discussed. In orde to deal with DTC scheme applied three level inverter, the selection of voltage vector is proposed to minimize switching frequency and torque ripple. The simulation results shows a validity of thi control scheme
프로펠러와 고양력 장치와의 공력간섭에 대한 수치해석 연구
박영민(Y. M. Park),김철완(C. W. Kim),정진덕(J. D. Chung),이해창(H. C. Lee) 한국전산유체공학회 2011 한국전산유체공학회지 Vol.16 No.4
A rotating propeller of turboprop aircraft gives much effect on the aerodynamic characteristics of wing such as lift, moment and stall. Specially propeller effect on the wing surface is much more dominant when aircrafts are in landing or take-off conditions. In the present paper, three dimensional Navier-Stokes simulations for the interaction of propeller and wing were carried out for medium sized turboprop aircraft. For rotating propeller, unsteady sliding mesh method was used to simulate a relative motion between moving and static bodies. For the power effect analysis in landing and take off configurations, double slotted flap was also considered and the aerodynamic characteristics were investigated. It was shown that the propeller slipstream enhanced the lift slope including maximum lift by eliminating local flow separation region and this enhancement was more dominant with high lift device.
CAN통신을 이용한 H-브릿지 멀티레벨 인버터의 PWM 동기화 및 위상전이 방법
박영민(Y.M.Park),유한승(H.S.Yoo),장성영(S.Y.Jang),이현원(H.W.Lee),이세현(S.H.Lee),서광덕(K.D.Seo) 전력전자학회 2004 전력전자학술대회 논문집 Vol.- No.-
H-브릿지 멀티레벨 인버터는 여러 개의 단상 Power Cell을 직렬로 연결함으로써 저전압 전력용 반도체를 사용하여 고전압을 얻을 수 있고, 정현파에 가까운 출력전압 파형을 얻을 수 있는 멀티레벨 인버터 토폴로지이다. 본 토폴로지는 출력전압 레벨에 비례하여 Power Cell의 수가 증가하므로, 주제어기의 연산능력에 대한 부담증가와 신호선의 많아지는 단점이 있다. 따라서 Power Cell제어를 직접적인 PWM 신호가 아닌 통신을 사용함으로써 이러한 단점을 극복할수 있으며, 신뢰성 측면이나 보수/유지 측면에서도 유리하다. 본 논문은 산업현장에서 신뢰성을 인정받아 많이 사용되고 있는 직렬통신 방식의 일종인 CAN통신 인터럽터를 이용한 H-브릿지 멀티레벨 인버터 Power Cell의 PWM 동기화 및 위상전이 방법에 관한 것이다. 제안된 방법의 주요 장점은 주제어기와 셀 제어기 사이에 직렬통신(CAN)을 사용함으로써 주제어기와 셀 제어기의 신호선의 단순화, 주제어기의 부담 감소, Power Cell의 모듈화, 셀 단위의 보호동작 용이, 확장성 향상 그리고 제어 신호 및 Power Cell의 신뢰성을 향상에 있다. 13레벨로 구성된 H-브릿지 멀티레벨 인버터 시험을 통해 제안된 방법의 타당성과 신뢰성을 입증하였다.
박영민(Y. M. Park),정진덕(J. D. Chung),김유신(Y. S Kim),최성욱(S. W. Choi) 한국전산유체공학회 2004 한국전산유체공학회 학술대회논문집 Vol.2004 No.-
Numerical optimization method of long endurance airfoil has been performed with a RSM(Response Surface Method) for smart UAV wing design. For the base line airfoil, NACA 64621 airfoil was selected and optimized to satisfy long endurance condition for smart UAV, Aerodynamic coefficients required for RSM are obtained by using 2-D Navier-Stokes solver with Spalart- Allmaras turbulence model. The optimized airfoil showed increased maximum lift and endurance factors together with reasonable thickness ratio.