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헬리콥터 로터 블레이드 제빙시스템 설계를 위한 블레이드 제빙해석 기법 연구
박남은(N.E. Park),우철훈(C.H. Woo),이석준(S.J. Yee),이재복(J.B. Yi),임태균(T.G. Lim) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
When the helicopter is flighting through icing condition, the ice could be accreted on fuselage and blades. The ice on blade could deform the blade configuration and increase the weight of blade. The unstable motions of blade make decreasing of performance, handling quality and structural stability due to the abnormal weight increase and configuration change. The helicopter deicing system is required to avoid risk by icing. Generally, the engine intake and the pitot sensor are adapted anti-icing system, but the rotor blade uses deicing system because the large size heater mat of blade needs a lot of power consumption. The anti-icing system is always active heater mat in icing condition; the deicing system is run alternately by on/off time sequence to avoid ice accretion on blade. Especially, due to the composite blade is weak by heat, over heat could make weak brittleness of blade. Thus, the de-icing system should be designed not only eliminate the ice on leading edge but also not damage the blade by heat source. First of all, the icing region estimation on blade is needed to design of rotor blade deicing system. In this paper, air flow field and multi-phase fluid analysis was performed by the commercial CFD s/w, SC/Tetra to calculate the collection efficiency around objects. The ice accretion analysis was performed by developed in-house code, ASTROD based on Messinger thermodynamic model. The computation result shows good estimations of icing region and ice thickness. In this study, de-icing situation is simplified that the blade surface adjoin with ice and thermal conduction occur at that interface. To analysis of convection on exterior surface of ice and internal heat power from heater mat by numerical method, discrete computational nodes of ice covered blade and consider phase change at the interface blade and ice. The numerical analysis result compared with ice wind tunnel test data of the blade to evaluate. The numerical method results show similar with experimental data about time to eliminate the ice and temperature of off-time range.
박남은(N.E. Park),우철훈(C.H. Woo),유광재(G.J. Ryu) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
HALO/HAHO are methods of delivering personnel, equipment and supplies from a transport aircraft at a high altitude via free-fall parachute insertion. HALO(High Altitude-Low Opening) and HAHO(High Altitude-High Opening) are also known as Military Free Fall. In the HALO technique, the parachutist opens his parachute at a low altitude after free-falling for a period of time, while in the HAHO technique, the parachutist opens his parachute at a high altitude just a few seconds after jumping from the aircraft. The HALO parachutist jumps from the helicopter at fast forward flight to avoid attack from the enemy. The trajectory of skydiving shows down/backward falling. The skydiver could be humped against external protuberance around aft fuselage of the helicopter at moment of jumping. The configuration design is needed to consider about crash skydiver against fuselage or the flight manual has to describe speed limitation during HALO. The helicopter pitch attitude of fuselage and downwash from rotor is become different by forward flight speed. In this paper, the helicopter attitude and the rotor blade motion were simulated by HOST(Helicopter Overall Simulation Tool) to use input data to CFD(Computational Fluid Dynamics) for HALO simulation. The rotor blade was modeled by actuator disk method and the interference analysis was performed including skydiver, fuselage and rotor downwash. The human body was modeled 95% height size and 5% weight of human database for conservative simulation. The analysis results of interference with skydiver and fuselage, drag coefficients by attitudes of diving, external forces of sky diver were inputted to equations of motion to calculate the diving trajectory. The forward flight speed was suggested from the trajectory simulation to avoid crash against with protuberance of helicopter.
전산공력소음해석을 통한 UH-60 제자리비행 공력소음 연구
박남은(N.E. Park),우철훈(C.H. Woo),최건묵(G.M. Choi),김철호(C.H Kim),이석준(S.J. Yee) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4
The helicopter development technology is improved by the increasing of computing power and advanced test facilities. The increasing efficiency of fuel consuming by the developing of improved lift-to-drag rotor system is the major issue, the noise reduction for ecology(civil area) and increase of survivability to reduce noise detection(battlefield) also are important. This investigation shows the helicopter external noise flight test methods, conventional military helicopter's(UH-60) experimental results and the numerical modeling method for aero-acoustic of rotor blade and the result of CAA(Computalional Aero-Acoustic) for main rotor blade.
박남은(N.E. Park),우철훈(C.H. Woo),이상기(S.G. Lee),이석준(S.J. Yee) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
The development technology for the helicopter is improved by the increasing of computing power and advanced test facilities. The increasing efficiency of fuel consuming by the developing of improved lift-to-drag rotor system is the major issue, the noise reduction for ecology(civil area) and increase of survivability to reduce noise detection(battlefield) also are important. This investigation shows the classification of helicopter external noise and requirements, the noise flight test methods, the numerical modeling method for aero-acoustic of rotor blade and the result of CAA(Computational Aero-Acoustic) for main rotor blade.
박남은(N.E. Park),우철훈(C.H. Woo),노현우(H.W. Rho),김철호(C.H. Kim),이석준(S.J. Yee) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
Helicopters and rotary-wing vehicles encounter a wide variety of complex aerodynamic phenomena and these phenomena present substantial challenges for computational fluid dynamics(CFD) models. This investigation presents the rotor aerodynamic analysis items for the helicopter development and variety aerodynamic analysis methods to provide the better solution to researchers and helicopter developers between aerodynamic problems and numerical aerodynamic analysis methods. The numerical methods to make an analysis of helicopter rotor are as below. - CFD Modelling: actuator disk model, BET model, fully rotor model, ... - Grid :sliding mesh, chimera mesh / structure mesh, unstructure mesh, ... - etc. : panel method, periodic boundary, quasi-steady simulation, incompressible, ... The choice of CFD methodology and the numerical resolution for the overall problem have been driven mostly by available computer speed and memory at any point in time. The combination of the knowledge of aerodynamic analysis items, available computing power and choice of CFD methods now allows the solution of a number of important rotorcraft aerodynamics design problems.
초음속 난류 유동장에 놓인 보트테일 형상 발사체 후방동체 기저 항력 감소에 대한 수치적 연구
박남은(N. E. Park),김재수(J. S. Kim) 한국전산유체공학회 2004 한국전산유체공학회 학술대회논문집 Vol.2004 No.-
Numerical analysis for pressure drag on boattail afterbodies have been studied by Mach number, boattail angle and length ratio of body diameter and base diameter using CFD-FASTRAN that the commercial external flow CFD code. The numerical results have been compared with the experimental data that have been shown pressure drag reduction and supersonic turbulent flow characteristics for boattail afterbodies. And the prediction equation for boattail base drag has been made by the numerical results about Mach number and boattail configuration parameters.
다중 투과면을 이용한 UH-1H 로터 블레이드의 제자리 비행 시 원방 소음 해석 연구
김기로(K.R. Kim),박수형(S.H. Park),박민준(M.J. Park),이덕주(D.J. Lee),박남은(N.E. Park),임동균(D.K. Im) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.3
In this study, aero-acoustics in far-field is computed for the UH-1H rotor blade in hovering flight. A Chimera grid method is applied in this simulation to consider the blade motion and moving effects. Multi-permeable surfaces surrounding a blade are constructed to include the flow noise generated from the shock wave and the tip vortices. A computation is performed with three-dimensional Euler’s equations. An acoustic analogy code using the Kirchhoff approach to Ffowcs Williams and Hawkings equations is applied to efficient the noise prediction caused by volume noise sources in far-field. The high speed impulsive noise on the rotor blade is predicted and validated according to the permeable surface locations. It is confirmed that the noise source caused by the shock waves generated on the blade surface is a dominant factor in the far-field noise prediction.