A turbofan engine includes a fan variable area nozzle includes having a first fan nacelle section and a second fan nacelle section movably mounted relative the first fan nacelle section. The second fan nacelle section axially slides aftward relative to the fixed first fan nacelle section to change the effective area of the fan nozzle exit area.

Gas turbine engine with axial movable fan variable area nozzle

A gas turbine engine includes a fan section, a gear arrangement configured to drive the fan section, a compressor section and a turbine section. The compressor section includes a low pressure compressor section and a high pressure compressor section. The turbine section is configured to drive compressor section and the gear arrangement. An overall pressure ratio, which is provided by a combination of a pressure ratio across said low pressure compressor section and a pressure ratio across said high pressure compressor section, is greater than about 35. The pressure ratio across the low pressure compressor section is between about 3 and about 8 whereas the pressure ratio across the high pressure compressor section is between about 7 and about 15.

Gas turbine engine compressor arrangement

A gas turbine engine includes a core housing providing a core flowpath. A shaft supports a compressor section arranged within the core flowpath. First and second bearings support the shaft relative to the core housing and are arranged radially inward of and axially overlapping with the compressor section.

Gas turbine engine shaft bearing configuration

A gas turbine engine according to an exemplary aspect of the present disclosure includes a gear train defined along an engine centeriine axis, and a spool along said engine centeriine axis which drives the gear train, the spool includes a low stage count low pressure turbine. In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the low stage count may include three to six (3-6) stages. Additionally or alternatively, the low stage count may include three (3) stages. Additionally or alternatively, the low stage count may include five (5) or six (6) stages.

Gas turbine engine with low stage count low pressure turbine

A gas turbine engine according to an exemplary aspect of the present disclosure includes a core nacelle defined about an engine centerline axis, a fan nacelle mounted at least partially around the core nacelle to define a fan bypass flow path for a fan bypass airflow, a fan variable area nozzle axially movable relative the fan nacelle to vary a fan nozzle exit area and adjust a pressure ratio of the fan bypass airflow during engine operation, and a gear system driven by a core engine within the core nacelle to drive a fan within the fan nacelle, the gear system defines a gear reduction ratio of greater than or equal to about 2.3.

Gas turbine engine with geared architecture

A turbofan engine control system is provided for managing a low pressure compressor operating line. The engine includes a low spool having a low pressure compressor housed in a core nacelle. A turbofan is coupled to the low spool. A fan nacelle surrounds the turbofan and core nacelle and provides a bypass flow path having a nozzle exit area. A controller is programmed to effectively change the nozzle exit area in response to an undesired low pressure compressor stability margin which can result in a stall or surge condition. In one example, the physical nozzle exit area is decreased at the undesired stability condition occurring during engine deceleration. A low pressure compressor pressure ratio, low spool speed and throttle position are monitored to determine the undesired stability margin.

Operational line management of low pressure compressor in a turbofan engine

The disclosed turbine engine includes a fan nacelle surrounding a fan and including an inlet arranged upstream from the fan. The inlet includes an inlet surface having a boundary layer flow. A flow control actuator is in fluid communication with the inlet surface. A boundary layer sensing device is associated with the inlet surface for detecting a boundary layer condition at the inlet surface. A controller is in communication with the flow control actuator and the boundary layer sensing device. The controller is programmed to command the flow control actuator in response to the boundary layer sensing device detecting an undesired boundary layer condition. In this manner, the flow control actuator generates a desired boundary layer condition.

Active flow control for nacelle inlet

The disclosed turbine engine (10) includes a fan nacelle (34) surrounding a fan (20) and including an inlet (35) arranged upstream from the fan (20). The inlet (35) includes an inlet surface (74) having a boundary layer flow. A flow control actuator (54) is in fluid communication with the inlet surface (74). A boundary layer sensing device (52) is associated with the inlet surface (74) for detecting a boundary layer condition at the inlet surface (74). A controller (50) is in communication with the flow control actuator (54) and the boundary layer sensing device (52). The controller (50) is programmed to command the flow control actuator (54) in response to the boundary layer sensing device (52) detecting an undesired boundary layer condition. In this manner, the flow control actuator (54) generates a desired boundary layer condition.

Wayne Hurwitz

Papers

Operational line management of low pressure compressor in a turbofan engine

Active flow control for nacelle inlet

Active flow control for nacelle air intake