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전산해석을 통한 고속철도 더블암 팬터그래프의 부재별 공력소음특성 연구
이상아(S. A. Lee),강형민(H. M. Kang),이영빈(Y. B. Lee),김철완(C. W. Kim),김규홍(K. H. Kim) 한국전산유체공학회 2015 한국전산유체공학회지 Vol.20 No.2
In this study, an aero-acoustic analysis around pantograph of a high speed train is performed. Computational technique and grid system is validated with wind tunnel test result and unsteady acoustic pressure data are used for analyzing noise level of each part of pantograph. FLUENT is used for flow analysis and LES(Large Eddy Simulation) is applied for analyzing turbulent flow. For acoustic analysis, Ffowcs Williams-Hawkings(FW-H) acoustics model is used and it bring the aero-acoustic characteristic of pantograph. As the result, contact strip, knee, substructure of pantograph is confirmed as a main source of aero-acoustic noise and it is dealt in various frequencies. The result is expected to help building improved grid system.
전산유체해석을 이용한 다양한 요철 형상에 대한 고압터빈 노즐 냉각유로 최적화 및 냉각 성능 비교
이상아(S. A. Lee),이동호(D. H. Rhee),강영석(Y. S. Kang),이관중(K. J. Yee),김규홍(K. H. Kim) 한국전산유체공학회 2014 한국전산유체공학회지 Vol.19 No.4
This study conducts shape optimization of rib turbulator on the internal cooling passage that has triangular cross-section of high pressure turbine nozzle. During optimization, various types of rib turbulator including angled, V-shaped, A-shaped and angled rib with intersecting rib are considered. Each type of rib turbulator is parameterized with attack angle(s), rib height, spacing ratio and bending/intersecting location. For optimization, Design of Experiment (DOE) and Kriging surrogate model are used to utilize computational resource more efficiently and Genetic Algorithm (GA) is used to search the optimum points. As a result, Pareto front of each type of rib turbulator with friction factor that relates to pressure drop in cooling passage and spatially averaged Nusselt number that relates to heat transfer on the wall is drawn and optimum points on the Pareto front are suggested.
전산해석을 통한 고속철도용 저소음 저저항 팬터그래프 형상설계 연구
정성민(S. M. Jeong),이상아(S. A. Lee),노주현(J. H. Rho),김규홍(K. H. Kim) 한국전산유체공학회 2015 한국전산유체공학회지 Vol.20 No.2
In this paper, study of high speed train pantograph arm shape and panhead cross-section for aerodynamic drag and noise reduction is performed. In previous research, it is known that knee of pantograph arm and panhead of pantogpraph are main sources of noise from high speed train pantograph. By numerical simulation using full scale pantograph model, pantograph arm and panhead optimization are performed. As a result, drag and noise are reduced at both studies about high speed pantograph.