STABILITY MARGIN AND CLEARANCE CONTROL USING POWER EXTRACTION AND ASSIST OF A GAS TURBINE ENGINE
FIG1 is a cross sectional schematic view of a gas turbine engine, in accordance with various embodiments
Referring now to the drawings, FIG1 schematically illustrates a gas turbine engine 20. The gas turbine engine 20 is disclosed herein as a two-spool turbofan that generally incorporates a fan section 22, a compressor section 24, a combustor section 26 and a turbine section 28. Alternative engines might include an augmenter section (not shown) among other systems or features. The fan section 22 drives air along a bypass flow path B in a bypass duct defined within a nacelle 15, while the compressor section 24 drives air along a primary or core flow path C for compression and communication into the combustor section 26 and then expansion through the turbine section 28. Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it will be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines, including three-spool architectures. The gas turbine engine 320 further includes a low spool power assist 360 and a high spool power assist 362. In various embodiments, the low spool power assist 360 is connected to the low speed spool 330 by a low spool tower shaft 302 and the high spool power assist 362 is connected to the high speed spool 332 by a high spool tower shaft 304. In various embodiments, the low spool tower shaft 302 includes a low spool bevel gear 310 in meshing engagement with a low spool gear pedestal 312. The low spool gear pedestal 312 is coupled to the low speed spool 330, which is similar to the low speed spool 30 described above with reference to FIG1. Similarly, the high spool tower shaft 304 includes a high spool bevel gear 306 in meshing engagement with a high spool gear pedestal 308. The high spool gear pedestal 308 is coupled to the high speed spool 332, which is similar to the high speed spool 32 described above with reference to FIG1. In various embodiments, the high spool gear pedestal 308 and the low spool gear pedestal 312 are mounted on the high speed spool 332 and the low speed spool 330, respectively.
cross-sectional schematic view
30
low speed spool
38
several bearing systems
48
fan drive gear system
15
nacelle
36
engine static structure
['1. A method of maintaining rotor tip clearance during a transient operation of a gas turbine engine, comprising: applying high spool auxiliary power to a high speed spool for a first time period; applying low spool auxiliary power to a low speed spool for a second time period; sensing one or more operational parameters of the gas turbine engine during the transient operation; and ceasing application of power to the high speed spool, based on the one or more operational parameters.']