Patent ID: 7299621
Filing Date: 2007-11-27
Classification: F01D,F02C,F02K,Y02T

Abstract:
1. A three-spool by-pass turbojet with a high by-pass ratio, the turbojet having a front fan and a rear fan at the front of an intermediate casing that presents an outer structural grid in the by-pass air flow and an inner structural grid in the main air flow, the fans having blades that extend radially outwards to a fan casing, which fan casing defines the outside of the by-pass air flow, the turbojet also having a low-pressure compressor for compressing the air coming into the channel for the main air flow, said front fan and said rear fan being rotated directly, and separately, by two shafts that are coaxial, wherein the low-pressure compressor is disposed axially between the blades of the front fan and the blades of the rear fan, and includes at least one ring of rotor blades extending from the periphery of a wheel that is driven by the drive shaft for the front fan, and at least two grids of stator vanes disposed axially on either side of said ring of rotor blades and radially inside a grid carrier ring, said ring being supported by an outer grid that is disposed in the by-pass air flow, said outer grid being supported by the fan casing, and wherein a variable-pitch stator is disposed downstream from said outer grid in order to ensure that the rear fan is acceptably matched.