Optimization of fan behavior in an aeronautical propulsion system

Abstract

An aeronautical propulsion system (1) comprises: - a fan section; - a combustion chamber (6); - a first turbine (8) configured to drive the fan rotor (9) and a first compressor (4) via a first shaft (11) around an axis of rotation (X); - a reduction mechanism (19) coupling the first shaft (11) and the fan shaft (20); - bearings (11a, 11b, 11c) configured to center the drive shaft (11) with respect to the axis of rotation (X); and - a mode damper (25) comprising an inner ring (30) mounted on a stator portion of one of the bearings (11a, 11b, 11c), an outer ring (32) and a fluid (29) confined between the inner ring (30) and the outer ring (32);and an axial length (L), a mounting radius (R) and a maximum radial clearance (C) of the mode damper (25) being dimensioned as a function of a free length and an average radius of the drive shaft (11) so as to satisfy the following formula: where: L11 is the free length of the drive shaft (11) and is expressed in meters (m); and R11 is the average radius of the drive shaft (11) between the first and second supports and is expressed in meters (m). Figure for the abbreviation: FIG. 1;