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공력 향상과 RCS 감소를 고려한 무인 전투기의 형상 최적설계
조영민(Y.M. Jo),최성임(S.I. Choi) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
Nowadays, Unmanned Combat Air Vehicle(UCAV) has become an important aircraft system for the national defense. For its efficiency and survivability, shape optimization of UCAV is an essential part of its design process. In this paper, shape optimization of UCAV was processed for aerodynamic performance improvement and Radar Cross Section(RCS) reduction using Multi Objective Genetic Algorithm(MOGA). Lift and induced drag, friction drag, RCS were calculated using panel method, boundary layer theory, Physical Optics(PO) approximation respectively. In particular, calculation applied Radar Absorbing Material(RAM) was performed for the additional RCS reduction. Results are indicated that shape optimization is performed well for improving aerodynamic performance, reducing RCS. further study will be performed with higher fidelity tools and consider other design segments including structure.
이슬기(S.G. Yi),권형일(H.I. Kwon),최성임(S.I. Choi),박부민(P.M. Park),강영석(Y.S. Kang) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
A multidisciplinary design optimization of EAV (Electric Aerial Vehicle) propeller is carried out to maximize the efficiency of propeller performance. An objective is to minimize torque/power while maintaining a thrust level of baseline configuration at a given RPM and thus to improve propeller efficiency. Structural safety is also calculated during the design process and is ensured to satisfy a safety margin. A high-fidelity CFD and FEM-based structures computation is employed for a design. To test the accuracy of the analysis tools, a wind-tunnel test is conducted for the baseline propeller blade at operating RPM and numerical prediction is validated against experiment data. A derivative-free multidisciplinary design methodology based on the Kriging approximation model is used to achieve the design goal of minimization of torque. Design variables are mostly related to the shape of the blade and include twist distribution at eight cross sections along the blade span as well as the planform shape of the blade around tip area. Design results demonstrate a reduction of torque by almost 5% at constant thrust. Safety margin is well satisfied for a new blade.
공력 향상과 RCS 감소를 고려한 무인 전투기의 형상 최적설계
조영민(Y.M. Jo),최성임(S.I. Choi) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.4
Nowadays, Unmanned Combat Air Vehicle(UCAV) has become an important aircraft system for the national defense. For its efficiency and survivability, shape optimization of UCAV is an essential part of its design process. In this paper, shape optimization of UCAV was processed for aerodynamic performance improvement and Radar Cross Section(RCS) reduction using Multi Objective Genetic Algorithm(MOGA). Lift and induced drag, friction drag, RCS were calculated using panel method, boundary layer theory, Physical Optics(PO) approximation respectively. In particular, calculation applied Radar Absorbing Material(RAM) was performed for the additional RCS reduction. Results are indicated that shape optimization is performed well for improving aerodynamic performance, reducing RCS. Further study will be performed with higher fidelity tools and consider other design segments including structure.
실험계획법을 이용한 판형핵연료집합체 스웨이징 가공조건 최적화
송화영(Hwayoung Song),권선칠(S. C. Kwon),정용진(Y. J. Jeong),최성일(Sung il Choi),박상호(Sangho Park) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.10
한국원자력연구원에서는 수출형 신형 연구로를 위한 판형핵연료집합체의 연구 및 개발을 진행하고 있다. 다수의 핵연료판과 좌·우 측면판의 조립에 스웨이징 기술을 사용하고 있으며, 조사 시험 내 구조 안전성과 추후 기계가공을 위해 높은 스웨이징 강도와 낮은 변형 크기를 갖는 것이 유리하다. 본 연구에서는 다구찌 실험계획법과 신호 대 잡음의 비 분석을 통해 판형핵연료집합체의 스웨이징 가공조건 최적화를 진행하였다. 실험 인자로는 스웨이징 롤러 깊이, 롤러 높이 및 롤러 이동속도로 하였으며, 각각 세 개 수준을 갖는 조건으로 실험을 실시하였다. 이러한 실험 자료는 추후 판형핵연료집합체 및 연구로 핵연료 제조기술 향상에 도움을 줄 수 있다. The Korea Atomic Energy Research Institute has developed a plate-type fuel assembly for a new research reactor. Swaging technology was used to assemble the fuel plates with the side plates, and this structure has advantages of high tensile strength and low deformation for stability during irradiation tests and machining. In this study, the swaging process was optimized using the Taguchi method, with the roller depth, roller height, and roller moving speed as the variables. This research is expected to contribute to the improvement of manufacturing technologies for other plate-type fuel assemblies.
이학진(H.J. Lee),조영민(Y.M. Jo),최성임(S.I. Choi),권종오(J.O. Kwon),안성목(S.M. Ahn) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
The sailing ship is a eco-friendly vessels that using wind energy to produce the additional thrust by the hull above the wing-sails. In this study, we performed the aerodynamic analysis around wing-sails by considering the interaction of wing-sails in fixed angle of attack. The wind direction that produces the maximum thrust of wing-sails can be obtained by calculating the thrust of wing-sails with, respect to the wind direction. In the aerodynamic analysis, we used three-dimensional compressible Navier-Stokes equation and hybrid grid to predict more viscous flow of boundary layer. We investigated that the maximum thrust of wing-sails at wind direction of 90 degree. After studying on the flow characteristic around wing-sails and effect of interaction, through derivative free based genetic algorithm and kriging surrogate model method to substitute a objective function evaluation we searched the optimal angle of attack that maximize the thrust of wing-sails. The result of optimization about wind direction of 45, 90 and 135 degree, we acquired about 7~23% of trust increment with trend of increasing the rear wing-sailss angle of attack by the interaction of wing-sails. Also we confirmed the thrust enhancement of 2~18% by conducting a three-dimensional validation.
유동 간섭 효과를 고려한 Wing-sails 공력 최적 설계
이학진(H.J. Lee),조영민(Y.M. Jo),권형일(H.I. Kwon),최성임(S.I. Choi) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
These day, an issues related with environments are becoming more pressing. We investigated potential next-generation vessel which makes use of the wing-sails to support existing fossil fuel-based propulsion system. The sailing-ship is a new concept eco-friendly vessel that uses the wind energy to produce additional thrust force by wing-sails above the hull. In this study, we focused on the aerodynamic analysis and design optimization of multiple wing-sails by varying the wind direction 15 degrees to 165 degrees. For the numerical analysis, we solved three dimensional compressible Navier-stokes equation with Spalart-Allmaras turbulent model. After the investigation of aerodynamic characteristics around wing-sails and the effect of flow interactions, we performed the design optimization of wing-sails by considering both single wing-sail and multiple wing-sails. In single wing-sail design, we found optimal value of deflection angle and flap length of single wing-sail to maximize the lift performance. In multiple wing-sails design, we carried out design optimization to find an optimal set-up of individual for each of the wing-sails that maximize total thrust of wing-sails. These optimal set-up include a deflection angle, deflection length and angle of attack of each wing-sails. Using a Kriging-based surrogate model and the derivative-free optimization method of genetic algorithms (GAs), we found the optimal set-up of the single and multiple wing-sails. The design optimization results showed that the total thrust of wing-sails has improved by 27~36% corresponding to the varying the wind directions.
e-Science 기반 EDISON 포탈의 항공우주분야 에어포일 공력 최적 설계 프레임워크 개발
권형일(H.I. Kwon),조영민(Y.M. Jo),이슬기(S.G. Yi),김사지(S.J. Kim),최성임(S.I. Choi) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
Design optimization is to find optimum of design space which is defined by design variables, using optimization algorithm. Recently, numerical design optimization including computational fluid dynamics (CFD) has been focused in not only aerospace engineering, but general engineering field because of many research and development for high performance computing. However it could hardly find the design optimization softwares and contents of which educational or research purposes in aerospace engineering. In this study, as one framework of EDISON DESIGN OPTIMIZATION, aerodynamic design optimization framework for an airfoil based on EDISON (EDucation-research Integration through Simulation On the Net) portal. As well as the softwares development, essential contents are also developed for the lecture associated with design optimization in the aerospace engineering. Software and contents on aerodynamic design optimization could be expected to be assisted in the lecture or lab..