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Paradot N.,Rolling Stock Engineering Center | Allain E.,Rolling Stock Engineering Center
Notes on Numerical Fluid Mechanics and Multidisciplinary Design | Year: 2012

For a high-speed train operating at 300km/h or more, the aerodynamic noise, which is induced by the pressure fluctuations of the air, reaches similar levels to the rolling noise, which is due to contact between the rail and wheel. For this reason, the study of the noise generated by the flow around the train is of great interest for the constructors and operators of high-speed trains. Although the main noise sources are now well identified, their localization is so far mainly based on experimental techniques using acoustic array measurements, applied either on small-scale models in a wind tunnel or on full-scale passing trains. Nonetheless, the numerical prediction of the aerodynamic noise is becoming more and more of a practical possibility, as the need is emerging for proper integration of technical solutions and optimizations at an early stage of design of new rolling stock. In this study, the aerodynamic noise generated by the power car of the TGV POS high-speed train is considered. This generation of TGV is named POS for Paris Ost-Frankreich Süd-Deutschland as it has been dedicated to connect Paris to the East of France (Strasbourg) and the South of Germany (Stuttgart, Munich). It has been introduced on the French and German high-speed network in 2007, where the operational speed has been increased from 300km/h to 320km/h (on French East-European line). For the two main reasons of the introduction of new rolling stock and the increase in speed, the aerodynamic noise is less well known and is expected to be more significant. A numerical study has been carried out to identify the sources of the noise and to quantify their level. Some results will be presented here. In order to obtain results of a high level of quality, a very detailed geometry was used, and the unsteady simulations were carried out at full scale. The complexity of the real geometry and the consideration of all parts and elements of bogie or pantograph frames enabled the influence to be determined of several shape modifications or of the integration of fairings on the level of aerodynamic noise. This gives some clues for solutions in terms of noise reduction. Among all the solutions tested, two examples have been selected and are presented in this paper. © 2012 Springer.

Agbli K.S.,CNRS Femto ST Institute | Hissel D.,CNRS Femto ST Institute | Sorrentino M.,University of Salerno | Chauvet F.,Rolling Stock Engineering Center | Pouget J.,University Paris Est Creteil
Energy Conversion and Management | Year: 2016

Energetic Macroscopic Representation (EMR) modelling approach is proposed to perform model-based reverse-engineering of a new railcar range, having six propulsion units, each consisting of a diesel engine and a traction motor. Particularly, EMR intrinsic features were exploited to perform phenomenological structuration of power flows, thus allowing proper and comprehensive modelling of complex systems, such as the under-study railcar. Based on some prospective real trips, selected in such a way as to enable realistic evaluation of effective railcar effort, EMR-based prediction of railcar energy consumption is performed. Furthermore, physical consistency of each powertrain component operation was carefully verified. The suitability of EMR approach was thus proven effective to perform reverse-engineering of known specifications and available experimental data, with the final aim of reconstructing a high fidelity computational tool that meets computational burden requirements for subsequent model-based tasks deployment. Finally, specific simulation analyses were performed to evaluate the potential benefits attainable through electric hybridization of the original powertrain. © 2016 Elsevier Ltd. All rights reserved.

Saussine G.,University Paris Est Creteil | Voivret C.,University Paris Est Creteil | Paradot N.,Rolling Stock Engineering Center | Allain E.,Rolling Stock Engineering Center
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | Year: 2015

The evaluation of the level of risk resulting from the phenomenon of ballast flight is currently receiving considerable attention, due to its direct impact on the safety and reliability of commercial railway operations. Of particular interest are the effects of this phenomenon on both railway infrastructure and rolling stock. It is difficult to analyse the ballast flight phenomenon, due to its dependence on a large number of variable parameters. Investigations carried out at SNCF have led to the proposal of a global approach, called the stress-strength interference analysis method, which can be applied by considering a relevant indicator to evaluate the risk due to flying ballast. This paper presents the work on the application of the proposed analysis approach to the ballast flight phenomenon performed within the FP7 EU AeroTRAIN project. The approach considers the influence of the passage of dedicated rolling stock and the resistance of the track to the displacement of ballast. It leads to the proposal of a methodology to evaluate the risk of ballast flight in high-speed rail operations; this allows the evaluation of the degradation rate of railway infrastructure and rolling stock due to this phenomenon to be performed. © MechE 2014.

Paradot N.,SNCF | Allain E.,Rolling Stock Engineering Center | Croue R.,Rolling Stock Engineering Center | De La Casa X.,Altran GmbH | Pauline J.,Altran GmbH
Civil-Comp Proceedings | Year: 2014

The French National Railway Company (SNCF) has led investigations on snow accretion phenomenon to reduce snow accumulations on a train's undercarriage. Wind tunnel experiments have been conducted to collect data on snow behaviour around a half scale railway mock-up and various prism shapes. The analysis of experimental results on prisms allowed the construction of a probability law for particle trapping on walls, in respect of the impact angle. The development of an Euler-Lagrange numerical method, combined with adapted mathematical laws (fitted with experimental results), led to a large calculation taking into account a whole TGV Duplex trainset at normal cruising speed. A methodology has been developed to make it possible using particle seeding by suspension from the ground and domain division processes for the fluid flow and particle trajectories. The method was then used to perform parametric studies and a mesh morphing tool was set to allow volume description of snow accretion. © Civil-Comp Press, 2014.

Frugier D.,Rolling Stock Engineering Center | Ladoux P.,National Polytechnic Institute of Toulouse
SPEEDAM 2010 - International Symposium on Power Electronics, Electrical Drives, Automation and Motion | Year: 2010

Since power electronics is used in railway traction, harmonic interactions between rolling stock and power supply installations have been observed. In the 25 kV-50 Hz French railway network, due to the traffic increasing, these problems can cause high traffic disturbances. To study and solve these problems, a systematic approach, based on simulation tools using a library of elementary models, is proposed. The first step is to develop a circuit modelling of railway power supply including all devices. Secondly, locomotive electrical models, including internal control loops, are inserted in the circuit and harmonic interactions can be analysed. Thanks to this method, the origin of voltage disturbances is more easily identified and a solution can be found in any case. © 2010 IEEE.

Letrouve T.,SNCF | Pouget J.,SNCF | Chauvet F.,Rolling Stock Engineering Center
2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings | Year: 2015

This paper propose to explore usage of Hardware-In-the-Loop simulation during development phase of hybrid railway locomotive. Nowadays, new studies are made on-line on a real prototype. The development at the same time of the control, the energy management strategy and particular subsystems behavior seems to be a good opportunity to decrease the cost and time of new research project. The Energetic Macroscopic Representation is used to describe the system in a causal way and to keep the readability of the developed HIL simulation whatever its complexity. An experimental setup has been developed to test this methodology. Experimental results are discussed at the end of this paper to show the good performances of this platform in the development phase. © 2015 IEEE.

De Bernardinis A.,Laboratory of New Technologies ERE LTN | Butterbach S.,Laboratory of New Technologies ERE LTN | Lallemand R.,Laboratory of New Technologies ERE LTN | Jeunesse A.,Rolling Stock Engineering Center | And 2 more authors.
Proceedings - ISIE 2011: 2011 IEEE International Symposium on Industrial Electronics | Year: 2011

This paper presents the study and experimental validation of a 9 kW lead-acid battery charger used to feed the 72V DC-Bus inside an hybrid electric locomotive demonstrator realized in the frame of the French research project PLATHEE (energy-efficient and environmentally friendly train platform). The proposed topology for the battery charger is a DC/AC/DC step-down converter structure using high frequency transformer and a double resonant series-parallel dipole. Main advantages of this topology are losses minimization due to soft switching operation, reduction of passive component weight and easy system integration. However, development and testing of the converter remain complex owing to high frequency constraints. Anti-parallel diodes of the DC/AC half-bridge dissipate losses in excess during switching sequences and their reverse recovery energy leads to constraining high current peaks. A solution consists in using fast Insulated Gate Bipolar Transistor (IGBT)/diode technology well suited to high frequency switching, and able to limit diode peak-current amplitude during switch-off. Electro-thermal endurance tests have been performed in order to characterize the thermal behavior of the semiconductor module and control its case temperature raise. The battery charger working has been first validated on laboratory test-bench using a battery emulator, and then implemented in the hybrid electric locomotive platform. © 2011 IEEE.

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