Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bowed rotor start mitigation system includes a variable position starter valve and a controller. The controller is operable to dynamically adjust the variable position starter valve to deliver a starter air supply to a starter to drive rotation of a starting spool of the gas turbine engine according to a dry motoring profile that continuously varies a rotor speed of the starting spool up to a point below a critical rotor speed.

Abstract: A compressor section for use in a gas turbine engine comprises a compressor rotor having a hub and a plurality of blades extending radially outwardly from the hub and an outer housing surrounding an outer periphery of the blades. A tap taps air at a radially outer first location, passing the tapped air through a heat exchanger, and returning the tapped air to an outlet at a second location which is radially inward of the first location, to provide cooling air adjacent to the hub. A gas turbine engine is also disclosed.

Abstract: A compressor of a gas turbine engine includes at least one rotor, and at least one stator, wherein the at least one stator includes a water channel wall located on a surface of the stator, wherein the water channel wall is configured to direct water away from a center line of the turbine engine and is located an offset distance from an outside wall of the compressor, wherein the offset distance is zero percent to twenty percent of the span of the stator.

Abstract: A gas turbine engine comprises a compressor, a combustor, a turbine, and an electronic engine control system. The compressor, combustor, and turbine are arranged in flow series. The electronic engine control system is configured to generate a real-time estimate of compressor stall margin from an engine model, and command engine actuators to correct for the difference between the real time estimate of compressor stall margin and a required stall margin.

Abstract: A compressor section of a gas turbine engine includes a bleed port having a flow splitter therein so as to define a downstream bleed channel having a downstream inlet and an upstream bleed channel having an upstream inlet that is positioned radially outward from the downstream inlet.

Abstract: A variable-geometry system for a gas turbine engine can be used to improve operations in various inclement weather conditions. This may be achieved by varying the orientation of an element in a gas turbine engine flowpath in response to a comparison between sensor-gathered parameter data and stored parameter values and ranges using a pre-programmed algorithm. The orientation of the element may be infinitely variable within a range of orientations.

Abstract: A gas turbine engine is defined wherein the inlet guide vanes leading into a core engine flow path are sized and positioned such that flow paths positioned circumferentially intermediate the vane are sufficiently large that a hydraulic diameter of greater than or equal to about 1.5 is achieved. This will likely reduce the detrimental effect of icing.

Abstract: A gas turbine engine is defined wherein the inlet guide vanes leading into a core engine flow path are sized and positioned such that flow paths positioned circumferentially intermediate the vane are sufficiently large that a hydraulic diameter of greater than or equal to about 1.5 is achieved. This will likely reduce the detrimental effect of icing.

Abstract: A total air temperature (TAT) sensor assembly is disclosed. The assembly includes a housing that accommodates a temperature sensor. The assembly also includes a first airfoil that includes a leading end and a trailing end and a second airfoil that includes a leading end and a trailing end. The first and second airfoils are disposed in a spaced-apart fashion that defines a curved passageway so incoming air can flow between the first and second airfoils before engaging the housing and the temperature sensor. The trailing ends of the airfoils are disposed on opposite sides of the housing and spaced apart from the housing to permit air flowing through the curved passageway to pass the housing.

Abstract: A gas turbine engine comprises a compressor, a combustor, a turbine, and an electronic engine control system. The compressor, combustor, and turbine are arranged in flow series. The electronic engine control system is configured to generate a real-time estimate of compressor stall margin from an engine model, and command engine actuators to correct for the difference between the real time estimate of compressor stall margin and a required stall margin.

Abstract: A system and a method for adjusting an angle of at least one stator vane of a low pressure compressor (LPC) of a two spool gas turbine engine is disclosed. Variable stator vanes are rotatably coupled to a stationary case in one of the stages of the LPC. An actuator is coupled to at least one of the variable stator vanes for imparting rotation of the stator vane about a radius of the case. Various coupling or linkage arrangements may be made so that rotation of one vane results in rotation of the other vanes disposed along the case. The controller includes the stored constraints, the ability to estimate operating condition, and the ability to estimate optimum targets.

Abstract: A gas turbine engine is defined wherein the inlet guide vanes leading into a core engine flow path are sized and positioned such that flow paths positioned circumferentially intermediate the vane are sufficiently large that a hydraulic diameter of greater than or equal to about 1.5 is achieved. This will likely reduce the detrimental effect of icing.

Abstract: A gas turbine engine includes a compressor, a combustor, and turbine enclosed in an engine case with the compressor having a plurality of alternating rows of rotating blades and stationary vanes. The gas turbine engine also includes a substantially circumferential groove formed in the engine case of the compressor section. The groove is substantially adjacent to a row of rotating blades to extract a portion of tip leakage flow from that row of blades and to route the extracted tip leakage flow to the turbine section for cooling turbine components. In the preferred embodiment of the present invention, the groove communicates with a plenum which communicates with the turbine section of the gas turbine engine via channeling pipes formed within the engine case.

Abstract: A system for controlling aeromechanical instability or flutter in turbofan engines having fan blades employs a sensor, such as an off-blade static pressure sensor or proximity detector mounted on a turbofan engine at an inlet of a rotor of the engine for generating a signal to detect resonance of the turbofan blades at frequencies associated with flutter. A controller is coupled to the sensor for generating by spatial Fourier decomposition from the sensor signal a command signal comprising a real time amplitude component and a spatial phase of disturbances of a predetermined nodal diameter and coincident with a natural frequency of resonance of a predetermined structural mode of the fan blades in the stationary frame. An actuator, such as a bleed valve or acoustic speaker, is mounted on the turbofan engine for damping flutter dynamics in response to the amplitude of the command signal.

Abstract: A pressure sensor (12) is located in the compressor stage of a gas turbine engine (10) to provide a pressure signal (PR1) that shows the compressor flow characteristics. The pressure signal (PR1) is applied to a bandpass filter (16) with roll-offs above and below N2. The difference between the filter output and a stored value for the pressure signal is integrated, and compressor bleed valves (18) are opened if the integral exceeds a stored threshold. The health of a compressor stage is determined by analyzing the magnitude of compressor pressure variations at N2 while accelerating the engine and by comparing the magnitude with values obtained from a compressor with a known stall margin.

Abstract: A system and method is provided for generating a real-time signal indicative of an energy-type instability precursor in a turbofan engine. A sensor is positioned in a compressor portion of a turbofan engine for generating a real-time signal indicative of energy of aerodynamic or aeromechanical resonance waves generated in the compression system. The signal is bandpassed to generate a filtered signal within a predetermined range of frequencies indicative of a precursor to instability such as rotating stall, surge or flutter. The bandpassed signal is squared in magnitude and then lowpassed to generate an instability precursor signal used to prevent imminent aerodynamic or aeromechanical instability from occurring in the aerocompression system.