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CAA를 이용한 소형 직류팬의 유동소음 및 예측에 관한 연구
전완호(W. H. Jeon),임태균(T. G. Lim),홍현기(H. K. Hong),御法川 學(Gaku Minorikawa) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
The paper describes the prediction method for the unsteady flow field and the aeroacoustic noise of an small axial fan. The prediction method is comprised of various CFD conditions and acoustic analogy by using Ffowcs Williams-Hawkings equation. The tested fan was an axial fan with impeller outside diameter 170 mm and 5 blades. Virtual anechoic room which has same size with real one was used for CFD. URANS and LES turbulence models were used and optimized mesh was selected with mesh dependence study. Calculation conditions were also studied such as time step and sampling time of noise analysis. In this paper, we got optimum analysis conditions and computational results, their results were compared with measured ones.
로터 블레이드 제빙 시스템 설계를 위한 예측 코드 개발 및 결빙 풍동 시험
우철훈(C.H. Woo),김경삼(K.S. Kim),이석준(S.J. Yee),이재복(J.B. Yi),임태균(T.G. Lim),김정일(J.I. Kim),박남은(N.E. Park) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.11
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. To protect the icing, the anti-icing system or the deicing system is used. Generally, the intake, the pitot sensor are adapted the 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 always actives heater mat in icing condition; the deicing system is run alternately by on/off time sequence to avoid ice accretion on blade. The design concepts of deicing system are needed estimation of heater mat location, scheduling on/off time sequence to avoid ice accretion, fixing of power consumption of heater mat. 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 results show good estimation of ice accretion shape and ice thickness. The development of computational tool for icing/deicing is just one part of deicing system design process. The understanding of physical phenomenon of icing and deicing on blade surface is needed for design of deicing system. The icing/deicing wind tunnel test was performed to evaluate the function of deicing system of rotor blade that showed the phase changing on blade surface from ice to water at 0℃. And the deicing system design information was acquired from experimental results by on/off time scheduling.