• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.2224-2229
• /
• 2008

High-Speed train has been developed and it becomes faster and environmental friendly. As trains run faster, Noise of trains is generated mainly by aerodynamic disturbance. Pantograph, both ends of trains, and gaps of coaches which are thought to be aerodynamic noise's factors are primarily studied. Pantograph is a similarly shaped metal framework on the roof of an electric high speed train, transmitting current from an overhead electric catenary wire. Panhead which contacts electric wires directly looks like a bluff strut, goes through flows, is sensitive to external disturbances and is one of the most important factors which decide whole vehicles' driving ability. In this study, aerodynamically robust optimized pantograph panhead shape is designed and then evaluated through subsonic wind tunnel test. To compare these with existing panhead rectangular shapes or circular cylinder shapes, By visualizing strong vortex flow patterns which are main noise sources, characteristics are compared and analyzed

• Journal of computational fluids engineering
• /
• v.20 no.2
• /
• pp.67-72
• /
• 2015

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.

• Proceedings of the KSR Conference
• /
• 2001.10a
• /
• pp.147-155
• /
• 2001

A data acquisition and signal processing system for evaluating the current collection system is developed, and subsequently applied to the measurement and analysis of the contact force in the current collection system of the proposed Korean High Speed Railway. The measurement of the contact force is based on an algorithm that employs the relationship between the contact force, the strain due to the bending moment and the panhead inertia. For the contact forces in the frequency range of less that 50Hz, the panhead can the modeled as a rigid body in the inertia calculation. For higher frequencies however, the bending vibration modes of the panhead need to be accounted for as well.

• Proceeding of EDISON Challenge
• /
• 2014.03a
• /
• pp.579-584
• /
• 2014

고속 열차의 속도가 점점 빨라짐에 따라 고속 열차 주행 시 발생하는 여러 공력적인 문제가 대두되고 있다. 그 중 고속 열차와 전력선을 이어주는 판토그래프에서의 소음 발생과 압상력 불안정 문제가 중요시 되어왔고 이에 대한 여러 선행연구가 진행되고 있다. 지금까지의 선행 연구는 원형, 사각형, 에어포일과 같이 기본적인 형상을 이용한 판토그래프 팬헤드의 최적 단면 형상을 찾는 데에 초점을 맞추고 있다. 본 연구는 이러한 주류의 접근 방식에서 벗어나 팬헤드에 구멍을 추가하여 그 효과를 보는 다양한 시도를 해보았고 구멍이 소음 발생과 압상력 불안정에 미치는 영향에 대하여 연구하였다.

• Journal of the Korean Society for Railway
• /
• v.15 no.6
• /
• pp.531-536
• /
• 2012

This study presents a result on aero-acoustic characteristics of pantograph panheads. To analyze the fluid flow around the panhead and resulting sound radiation, simple models of panhead were used in the numerical simulations called Lattice-Boltzmann method. The simulation results were verified using the wind tunnel test. The main aerodynamic noise was generated from the vortex shedding which is characterized by the Strouhal number, flow speed and geometry. The reduction in the radiated noise with simultaneously achieving increased lifting force was implemented for the simple rectangular geometry used in this study. Also, it was shown that the radiated sound power was significantly reduced by minimizing vortex shedding using through-holes or streamline shapes.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.133-138
• /
• 2010

This paper describes on aerodynamic characteristics of pantograph system for Next generation high speed train(HEMU-400). The pantograph which supports electric power is located on the roof. Because of this, it generate high drag, severe acoustic noise and vibration which induced unstable flow due to complex configuration. Therefore, the design of high efficient pantograph needs to increase operational speed. In this research, wind tunnel tests were performed to design a high efficient pantograph system using 1/4 scaled model which were KTX-II pantograph, single arm pantograph and periscope type pantograph with square cylinder shape panhead and optimized shape panhead. For real operational condition, flow directions were adapted by rotation of pantograph. From this results of wind tunnel, it is checked that the pantograph with optimized panhead and single arm type or periscope type has better aerodynamic performance. In addition, lift control device and spoiler in pantograph were tested to investigate the validity of application.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.2
• /
• pp.83-91
• /
• 2003

Pantograph design Process must be considered in terms of stability of aerodynamics and reduction of aeroacoustics. Furthermore pantograph needs to be insensible to severe circumstance condition like typhoon, tunnel, a change of season. In this paper, robust design of panhead sections is conducted based on the Taguchi's design of experiment method. In the aeroacoustic noise analysis, an acoustic analogy using the Ffowcs Williams and Hawkings(FW-H) equation is used to calculate the flow induced sound pressure level in aeroacoustics. From the near-field CFD analysis data, the far-field noise is predicted at the positions of 25 m away from Pantograph. Based on aerodynamic(CFD) and aeroacoustic(FW-H) analysis data, the optimal sizing and Positioning of panhead elements are determined using robust design optimization method. Design parameters such as thickness, length and radius are controllable factors, while outdoor air temperature and atmospheric pressure are considered as uncontrollable factors in the context of Taguchi's approach. A number of CFD simulation and aeroacoustic analysis are performed based on orthogonal arrays. In this paper, two-step optimization method is used as a parameter design procedure. It is executed using signal to noise(S/N) ratio and analysis of means(ANOM) method. So Thus, an optimal level of design parameters Is extracted to minimize the disconnection ration between contact strips and catenary system, and reduce the far-field aeroacoustic noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1235-1241
• /
• 2001

Pantograph design process must be considered in terms of stability of aerodynamics and reduction of aeroacoustics. Furthermore Pantograph needs to be insensible to severe circumstance condition like typhoon, tunnel, a change of season. In this paper, robust design of panhead sections is conducted based on the Taguchi's design of experiment method. In the aeroacoustic noise analysis, an acoustic analogy using the Ffowcs Williams and Hawkings (FW-H) equation is used to calculate the flow induced sound pressure level. From the near-field CFD analysis data, the far-field noise is predicted at the positions of 25m away from panhead contact strips. Based on aerodynamic (CFD) and aeroacoustic (FW-H) analysis data, the optimal sizing and positioning ofpanhead elements are determined using robust design optimization method. Design parameters such as thickness, length and radius are controllable factors, while outdoor air temperature and atmospheric pressure are considered as uncontrollable factors in the context of Taguchi's approach. A number of CFD simulation and aeroacoustic analysis are performed based on orthogonal arrays. Using a parameter design procedure associated with signal-to-noise (SIN) ratio and sensitivity analysis, an optimal level of design parameters are extracted to minimize the disconnection ratio between contact strips and catenary system, and reduce the far-field aeroacoustic noise.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.367-372
• /
• 2001

The paper presents an improved way of aerodynamic quality in Korean Very High Speed Railway, The pantograph model being under development dissatisfies the required grade of aerodynamic lift force. So the present work proposes modified configurations of panheads to maintain consistent aerodynamic characteristics. Analysis has been performed using commercial CFD program. Simulation based analysis has been conducted with two different models. One is to attach the thin plate on the crossbar and the other is the use of trapezoidal cross section in contact strip. Various length of thin plate is simulated for flow velocity and acceptable value of plate length is selected which satisfy the necessary average lift force. Aerodynamic variation on the panheads strip is studied.

• Journal of the Korean Society for Railway
• /
• v.7 no.3
• /
• pp.232-238
• /
• 2004

The dynamic characteristics of the current collection process of the high-speed railway are investigated through signals acquired during a test run. The signals are obtained from accelerometers, load cells, and strain gauges attached to various positions of the pantograph, and they are processed in time-and frequency-domains to obtain the dynamic characteristics. The main natural frequency of the pantograph is found to be 8.5Hz. There also are components at low frequencies varying linearly with the train speed. The contact frequency components above 20Hz is attenuated as they pass through the secondary suspension. The main frequency component of the load cell signal is found to be related with the rolling motion of the panhead generated by the stagger in the catenary.