CPC F04D 17/025 (2013.01) [F01D 17/26 (2013.01); F01D 19/00 (2013.01); F02C 7/264 (2013.01); F02C 9/18 (2013.01); F05D 2240/11 (2013.01); F05D 2270/80 (2013.01)] | 12 Claims |
1. A method of controlling compressed airflow in a gas turbine engine that includes a combustor, an axial-centrifugal compressor disposed upstream of the combustor and having an axial compressor and a centrifugal compressor, and a shroud that surrounds at least a portion of the axial compressor and has a surge bleed plenum defined therein, wherein the combustor has a combustor air inlet, wherein the axial compressor has an axial compressor inlet and an axial compressor outlet, wherein the centrifugal compressor has a centrifugal compressor inlet in fluid communication with the axial compressor outlet and a centrifugal compressor outlet in fluid communication with the combustor air inlet, and wherein the surge bleed plenum is in fluid communication with, and receives compressed air from, the axial compressor outlet, the method comprising the steps of:
providing a secondary airflow duct having a duct inlet and a duct outlet, where the duct inlet is in continuous fluid communication with the surge bleed plenum and the duct outlet is in continuous fluid communication with the combustor air inlet; and
selectively moving a valve that is mounted on the secondary airflow duct between a closed position, in which compressed air from the axial compressor outlet cannot flow, via the surge bleed plenum, through the secondary airflow duct and into the combustor air inlet, and at least one open position, in which compressed air from the axial compressor outlet flows, via the surge bleed plenum, through the secondary airflow duct and into the combustor air inlet.
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