AERO-ACOUSTIC OPTIMIZATION OF THE FANS AND COOLING CIRCUIT ON SNCFʹS X 72500 RAILCAR

This paper presents the results of studies concerning the fans on SNCFʹs X 72500 railcar with a view to reducing the level of ambient noise. The paper first describes the operation of an axial fan and then the main sources of noise generated by this type of fan. The interactions between acoustic emissions and mass output are then described to illustrate the advantages of an acoustic and pneumatic predictive device. Finally, a new design of axial wheel on the SNCF railcar is described which has reduced the acoustic emission by 10 db whilst still improving the initial ventilation performance.