Patent ID: 8240124
Filing Date: 2012-08-14
Classification: F02C,F05D

Abstract:
1. A method of taking auxiliary power from an airplane dual-spool turbojet comprising, from upstream to downstream, a fan, a low pressure compressor, a high pressure compressor, a combustion chamber, a high pressure turbine and a low pressure turbine, wherein said low pressure turbine is mechanically connected to a first axial shaft which drives said fan and said low pressure compressor such that said fan produces thrust, said high pressure turbine is mechanically connected to a second axial shaft which drives said high pressure compressor, the method comprising: taking off said power via a radial shaft mechanically coupled to said second axial shaft and driven by the high pressure turbine; and controlling degradation of efficiency of said low pressure turbine, within an idling operating range, to enable said high pressure turbine to operate at a speed that is sufficient for supplying the required auxiliary power, wherein the efficiency is degraded by increasing radial clearance of moving blades of said low pressure turbine using a low pressure turbine axis clearance control system, such that a rotation speed of said high pressure turbine is increased and the thrust produced by said fan is compatible with said turbojet operating at idling speed.