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고속철도 장대터널에서 밸러스트 트랙 효과에 대한 수치적 연구
김홍근(H.K. Kim),오현주(H.J. Oh),김동현(D.H. Kim),이정희(J.H. Lee),김찬중(C.J. Kim) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
This paper reports the numerical research of the relief effect of compression wave and micro wave between a high speed train and ballast ground track. When a high-speed train enters a narrow tunnel, a compression wave is generated ahead of the train. From the tunnel exit, some part of these wave is reflected back and other part of wave spouts to outside as a micro-wave. In the tunnel, compression wave has tendency of decreasing because of the viscosity from ballasted track. As a results, micro-wave also decreases. This ballast effect is not insignificant for a short tunnel. But it has an effect on pressure relief through the very long tunnel. To numerically analysis this effect, computational fluid dynamics is used on based of two-dimensional unsteady flow model and solving Navier-Stokes Equation using by Fluent software. The length of single track tunnel was 5km, 10km and compared with ballast ground track and slab ground track.
후드가 존재하는 고속철도 터널에 배출공을 이용한 미기압파 저감에 대한 수치적 연구
오현주(H. J. Oh),김홍근(H. K. Kim),김동현(D. H. Kim),이정희(J. H. lee),김찬중(C. J. Kim) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
This paper shows numerical study on micro pressure wave reduction according to the hood and ventpipes on the hood in high-speed railway tunnel. The evolution of pressure waves is calculated by using a Fluent V.13, where layering method of dynamic mesh and the 2D axis-symmetric model. In order to validate, the values experimented by Wu are used to verify in this research. From the results, We can have a conclusion that the role of hoods respectively were different according to the position.
석진규(J.K. Seok),강성관(S.K. Kang),송웅협(W.H. Song),조원우(W.W. Jo),노의철(E.C. Nho),김인동(I.D. Kim),전태원(T.W. Chun),김홍근(H.G. Kim) 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1
This paper deals with a welding time for a spot welding system. Conventional welding machine adopts several tens of switching devices connected in parallel to obtain a short welding time. This paper analyzed a welding system consisting with 4 IGBT switchs for a full-bridge inverter and conventional 60 [Hz] transformer. The simulation and experimental results show that the welding time can be minimized to 5 [ms] with the proposed scheme.
김용균(Y.K Kim),최종우(J.W. Choi),김홍근(H.G. Kim) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(2)
The frequency and phase angle of the utility voltage are important in many industrial systems. this paper present a detailed analysis of single-phase digital PLL control for utility connected systems. and its performance under utility conditions with nois is discussed. The experimental results demonstrate phase tracking capability in the single-phase grid-connected operation<br/>