The influence of aerodynamic forces on the vehicle bodywork of railway traction

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1 The influence of aerodynamic forces on the vehicle bodywork of railway traction Sorin ARSENE*,1, Ioan SEBESAN 1 *Corresponding author 1 POLITEHNICA University of Bucharest, Transport Faculty, Depart Rolling Stock Railway Splaiul Independentei no. 313, Sector 6, Code , Bucharest, Romania sorinarsene@gmail.com*, ioan_sebesan@yahoo.com DOI: / Received: 05 September 2015 / Accepted: 10 November 2015 / Published: March 2016 Copyright Published by INCAS. This is an open access article under the CC BY-NC-ND license ( The 36 th Caius Iacob Conference on Fluid Mechanics and its Technical Applications october, 2015, Bucharest, Romania, (held at INCAS, B-dul Iuliu Maniu 220, sector 6) Section 1. Aerodynamic Design Abstract: The increase of the driving speed in railway system requires a comprehensive analysis on the vehicle aerodynamics, on the manner in which the performance is affected or related to the additional loads on various components. The aerodynamic forces have a greater impact in the case of medium and high values of the relative velocity of the air flow near the vehicle. This paper aims to analyze the loads caused by the aerodynamic forces on the bodywork of the electric locomotive, of 5100 kw LE 060 EA type. In this respect, the bodywork and the chassis of locomotive were modelled in a 3D format; then a series of air flow simulations were performed for different values of the vehicle velocity ranging between 0 km/h and 200 km/h. Key Words: bodywork structure, aerodynamic forces, railway vehicles. 1. INTRODUCTION During their movement, on the rail motor vehicles the thrust developed by the power equipment is acting together with the amount of resistant forces opposing the movement in the desired direction. [1] The resistance forces acting while the vehicle is moving on the towing section profile which is in alignment and plane (straight line without ruling gradients) are determined by friction, such as: friction on the axles bearings, rolling and / or sliding friction, road surface friction, air friction, etc. [1] Generalized formula for determining the resistance to motion for the railway vehicles, also known as Davis relationship [2-5], is: R A B v C v 2 veh (1) Where R veh Total resistance to motion of the vehicle; A Mechanical rolling resistances caused by the axle loads; B v Non-aerodynamic resistance to motion; C v 2 Aerodynamic drag; v Speed of the vehicle., pp ISSN

2 Sorin ARSENE, Ioan SEBESAN 24 Davis constants from the resistance to motion formula depend on the type and characteristics of each vehicle. In the case of locomotive of 5100 kw LE 060 EA type these constants are given in the literature of the field [1, 6], and summarized in Table 1: Table 1 The values of Davis constants for locomotive of 5100 kw LE 060 EA type Type of vehicle A [N] B [N/(km/h)] C [N/(km/h)2] LE 060 EA - v.1 (120 t) ,9 0,333 LE 060 EA - v.2 (120 t) ,3 The explicit formula for parameter "c" regarding aerodynamic resistances according to the literature of specialty [7-15], is: Cx S c (2) 2 2 Fax where: Cx aerodynamic coefficient of air gliding, also known under the name 2 S v of air penetration coefficient (dimensionless); S the frontal area of the vehicle in the cross-sectional area (m 2 ); the air density in the moving vehicle (kg/m 3 ); F ax drag frontal force (N); v the speed of the fluid (air) (m/s). 2. SIMULATION OF THE AIR FLOW For this simulation, we considered the model of the bodywork and the chassis of the electric locomotive, of 5100 kw LE 060 EA type. This type of locomotive is most used by the railway companies from Romania for the traction of the train. We started by the geometric modeling of the bodywork and the chassis of electric locomotive at scale 1:1, using Autodesk Inventor. (fig. 1) a) The bodywork of the locomotive of 5100 kw LE 060 EA type b) The chassis of the locomotive of 5100 kw LE 060 EA type

3 25 The influence of aerodynamic forces on the vehicle bodywork of railway traction c) The assembly formed by the bodywork and the chassis Fig. 1 The 3D model of assembly formed by the bodywork and the chassis of the electric of 5100 kw LE 060 EA type at scale 1:1 To simulate the air flow we considered eleven cases in which the vehicle moves at a constant speed in the range of 0km/h 200km/h (5m/s, 10m/s, 15m/s, 20m/s, 25m/s, 30m/s, 35m/s, 40m/s, 45m/s, 50m/s, 55m/s). The delimitation of the air flow volume is managed as follows: - we considered A vertical plane corresponding to the wheel track of the vehicle and another plane located at 11.5 m from it were considered; - two planes symmetrically located at 10 m from the vehicle longitudinal plan were considered for the transverse section; - two planes located at 15 m and 25 m, respectively, from the transverse plane were considered for the longitudinal section. The first plane of the longitudinal section (15 m) corresponds to the front part of the locomotive considered in the air flow direction while the second plane of the section (25 m) corresponds to the rear part of the vehicle (fig. 2). 11,5 m 10 m 10 m 15 m 25 m Fig. 2 The considered air flow volume Two values were considered as input parameters for the atmospheric conditions: Pa for pressure and K for temperature, respectively.

4 Sorin ARSENE, Ioan SEBESAN 26 By simulating the air flow, we could determine the pressures exerted on the bodywork chassis assembly, the dynamic pressure of the air and the aerodynamic resistances for the 11 analyzed modes. Fig. 3 shows the distribution of the pressure with the contour lines on the bodywork and the chassis obtained by simulations. V=5 m/s V=30 m/s V=10 m/s V=35 m/s V=15 m/s V=40 m/s V=20 m/s V=45 m/s

5 27 The influence of aerodynamic forces on the vehicle bodywork of railway traction V=25 m/s V=50 m/s V=55 m/s Fig. 3 Pressures exerted on the bodywork and the chassis of 5100 kw LE 060 EA type The variation of the aerodynamic resistance generated by the bodywork and the chassis obtained during the simulation flow of air is shown in fig. 4. Fx [N] m/s 10 m/s 15 m/s 20 m/s 25 m/s 30 m/s 35 m/s 40 m/s 45 m/s 50 m/s 55 m/s Fig. 4 Aerodynamic resistances obtained by simulation The superposition of the resistance to motion of the locomotive over the fixed/stabilized values of aerodynamic resistance caused by the bodywork and the chassis is shown in fig. 5. F ax, R L [N] v Fax RL [m/s] Fig. 5 The total resistance to motion of the locomotive and aerodynamic drag of bodywork and the chassis obtained by simulation t [s]

6 Sorin ARSENE, Ioan SEBESAN CONCLUSION As can be seen from fig. 3, increasing the speed of the vehicle determines, implicitly increasing pressure exercised on the bodywork and the chassis for the analyzed locomotive. The aerodynamic forces exert a dynamic load on the bodywork and the chassis of the traction vehicle according to its displacement speed. The increased speed of moving will lead to higher values of aerodynamic forces. These values represent a growing percentage of the value of the total resistance to motion of the vehicle. ACKNOWLEDGEMENT This work is supported by the Sectorial Operational Programme Human Resources Development (SOP HRD), financed from the European Social Fund and the Romanian Government under the contract number POSDRU/159/1.5/S/ REFERENCES [1] S. Arsene, I. Sebeşan, Analysis of the resistance to motion in the passenger trains hauled by the locomotive LE 060 EA 5100kW, INCAS BULLETIN, ISSN , DOI: / , Volume 6, Issue 3, pp , [2] A. Steimel, Electric Traction - Motive Power and Supply, Munich, Editor: Elmar Krammer, [3] D. A. Nicola, D. C. Cismaru, Tractiune electrica - Fenomene. Modele. Soluții, vol. I, Craiova, SITECH, [4] J. M. Allenbach, R. Kaller, Traction Électrique, vol. 2, [5] S. Arsene, I. Sebeşan, A. Certan, G. Popa, Influence resistance at advancing on fuel consumption for vehicles that use an internal source of energy, Procedia - Social and Behavioral Sciences vol. 186, pp , [6]S. Arsene, Teză de Doctorat - Contribuţii privind îmbunătăţirea performanţelor de tracţiune ale vehiculelor electrice, Universitatea Politehnica din București, [7] I. Sebeşan, S. Arsene, C. Stoica, Experimental study on determination of aerodynamic resistance to progress for electric locomotive LE 060 EA1 of 5100 kw, Scientific Bulletin-University Politehnica of Bucharest, Series D, vol. 75, Issue. 4, p , [8] I. Sebesan, S, Arsene, C. Stoica, Experimental analysis for aerodynamic drag of the electric locomotives, INCAS BULLETIN, (online) ISSN , (print) ISSN , ISSN L , vol. 5, Issue 3, DOI: / , pp , [9] I. Sebesan, S. Arsene, Study on aerodynamic resistance to electric rail vehicles generated by the power supply, INCAS BULLETIN, (online) ISSN , (print) ISSN , ISSN L , Volume 6, Special Issue 1, DOI: / S1.17, pp , [10] R. S. Raghunathan, H.-D. Kim, T. Setoguch, Aerodynamics of high-speed railway train, Progress in Aerospace Sciences, vol. 38, Issues 6 7, ISSN: , pp , [11] S. Arsene, I. Sebeşan, G. Popa, The influence of wind on the pantograph placed on the railway Electric vehicles bodywork, Procedia - Social and Behavioral Sciences vol. 186, pp , [12] S. Arsene, I. Sebeşan, Analysis of the wind influence on the aerodynamic drag in the case of a certain emplacement of the pantograph on the electric rail vehicles, INCAS BULLETIN, ISSN , DOI: / , Volume 7, Issue 1, pp. 3 12, [13] S. Arsene, I. Sebeşan, Influence of wind on aerodynamic drag for the second case of the arrangement of the equipment on the LE 060 EA locomotive bodywork, INCAS BULLETIN, ISSN , DOI: / , Volume 7, Issue 2, pp , [14] S. Arsene, The vertical forces introduced by wind on the active pantograph from bodywork of locomotive LE 060 EA of 5100 kw, Applied Mechanics and Materials, ISBN-13: , Doi: / Vols , pp , [15] S. Arsene, Influence of wind on the aerodynamic resistance for a case of the arrangement of the equipment on locomotive bodywork LE 060EA, Applied Mechanics and Materials, ISBN-13: , Doi: / Vols , pp , 2015.