Analysis of Aerodynamic Brakes in Mainline of Ethiopia Railway Corporation (ERC)
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Date
2015-03
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Addis Ababa University
Abstract
Aerodynamic brakes are used as auxiliary braking system in rolling stock. The aerodynamic brake is defined as a stiffened plate subjected to lateral pressure load considering buckling behavior. This research is prepared for the computational fluid analysis (CFD) of aerodynamic braking plate by using Finite Element Method to improve arrangement of braking plate and analyze for Ethiopian National Train (ENT).Through the research the current speed of ENT IS taken(120km/hr) and also assumed future speed of 300km/hr is also considered.
The analysis is done using the parameters of the rolling stock to be used by Ethiopian Railway Corporation. The assembly of the train body and braking plate area was modeled by using CATIA software. After modeling, analysis for determination of brake force is used by ANSYS Fluent and also the amount of pressure is discussed under four main cases. When the braking plates are positioned at four different angles (450, 600, 750, & 900).The results showed that the drag coefficient increases as the speed increases and also at 120km/hr the aerodynamic effect is less than at 300km/hr.
At 120km/hr all the results of pitch moment coefficient were less than one this shows that the train is stable under all four cases. The drag force at an arrangement of 900 was found to be enough to slow down the train at a deceleration of 0.68m/s2 .All the other three cases were invalid because the system cannot achieve the required deceleration. The analysis when the two trains cross each other both equipped with aerodynamic braking plate was also analyzed. The result achieved was the maximum pressure during crossing was 2.39kpa.this pressure can be easily resisted by the window glass which can resist 8.3kpa pressure. Therefore the system can work without any pressure effect. The results were discussed by displaying the drag coefficient, the lift coefficient, residuals, moment coefficient and pressure
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Keywords
CFD, aerodynamic drag, shape optimization, cross wind stability, Fluent, Inflation