Method of operating adaptive core engines

Abstract

A method of operating a compressor in an adaptive core engine is disclosed. The method comprises the steps of operating a front block compressor to increase pressure of a fluid to a first pressure ratio in a high-power mode operation; operating a rear block compressor coupled to the front block compressor such that the front block compressor and the rear block compressor operate at the same physical speed; closing a rear block stator vane located axially forward from the rear block compressor such that the flow of the fluid into the rear block compressor is substantially cut off; and keeping a blocker door opened such that substantially all of the fluid pressurized by the front block compressor flows through a bypass passage during the high-power mode operation. The operation may be transitioned from the high-power mode to a low-power mode by opening a rear block stator such that the rear block compressor receives at least a portion of the fluid flowing from the front block compressor and maintains an overall engine pressure ratio.