Patent ID: 11885263
Assignee: PRATT & WHITNEY CANADA CORP.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 15:
16. A method of operating an aircraft engine having a secondary air system (SAS), the method comprising: receiving a secondary airflow from a source provided by the aircraft engine, the secondary airflow including one or more air streams flowing downstream of the source; flowing each of the one or more secondary air streams through a respective SAS feed pipe and into a respective hollow strut extending radially through a main gas path of an engine core of the aircraft engine; flowing the one or more secondary air streams from the respective hollow strut into a buffer cavity for feeding the secondary airflow to the engine core, the buffer cavity formed by a plenum axially aligned with the hollow strut, the buffer cavity extending partially circumferentially around the central axis from a first end positioned at a strut outlet of the respective hollow strut to a second end positioned at a strut outlet of a second respective hollow strut circumferentially offset from the first end, within an inter-compressor case of the aircraft engine case to provide circumferential flow of the secondary airflow downstream of an outlet of the respective hollow strut, a portion of a circumference of the inter-compressor case being devoid of the buffer cavity; and generating a first flow restriction in each of the secondary air streams during a first power regime of the aircraft engine, and generating a second flow restriction in the secondary air streams during a second power regime of the engine, the second power regime being lower than the first power regime, and the second flow restriction being less than the first flow restriction.