Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. The turbine section includes a high pressure turbine comprising a plurality of turbine blades. The gas turbine engine includes a tap for tapping air that is compressed by the compressor, to be passed through a heat exchanger to cool the air, the cooled air to be passed to the plurality of turbine blades. A sensor is located downstream of a leading edge of the combustor, and is configured to measure a characteristic of the cooled air. A controller is configured to compare the measured characteristic to a threshold and control an operating condition of the gas turbine engine based on the comparison.

Abstract: This disclosure relates to a buffer system for a gas turbine engine. An exemplary gas turbine engine includes, among other features, a buffer manifold in an intershaft region. The buffer manifold is configured to direct a flow of air between a first air seal and a first oil seal, and to direct another flow of air between a second air seal and a second oil seal.

Abstract: A rotor blade for a gas turbine engine includes a blade extending from a root and a contoured tip portion at a first end of the blade. The first end is opposite the root. The contoured tip portion includes a first sloped region and a second sloped region. The second sloped region is steeper than the first sloped region, relative to a platform.

Abstract: A tap is connected to a location upstream of a downstream most location in a compressor to a heat exchanger. Downstream of the heat exchanger is a shut off valve and a cooling compressor. The cooling compressor is connected to a chamber provided with a check valve configured to selectively allow flow directly from a downstream location in the compressor. There is a system for stopping operation of the cooling compressor, and a control for closing the shut off valve. The cooling compressor is configured to compress air to a greater pressure than the higher pressure, such that the check valve is configured to maintain a closed position, but when said cooling compressor is not providing compressed air, the at least one check valve is configured to allow said higher pressure flow into the chamber. A method is also disclosed.

Abstract: A bearing assembly for a gas turbine engine includes, among other things, a bearing housing extending along an axis to define a bearing compartment, a lubricant seal assembly adjacent to the bearing housing to bound the bearing compartment, an air seal assembly defining a vent cavity along the bearing housing, wherein a mixing cavity is defined between the lubricant seal assembly and the air seal assembly, and wherein the bearing housing defines an airflow supply passage, an airflow vent passage and a scupper passage having respective fluid ports at different circumferential positions relative to the axis, the fluid port of the airflow vent passage fluidly coupled to the vent cavity, and the fluid ports of the airflow supply and scupper passages fluidly coupled to the mixing cavity. A method of sealing for a gas turbine engine is also disclosed.

Abstract: This disclosure relates to a buffer system for a gas turbine engine. An exemplary gas turbine engine includes, among other features, a buffer manifold in an intershaft region. The buffer manifold is configured to direct a flow of air between a first air seal and a first oil seal, and to direct another flow of air between a second air seal and a second oil seal.

Abstract: A bearing assembly for a gas turbine engine includes, among other things, a bearing housing extending along an axis to define a bearing compartment, a lubricant seal assembly adjacent to the bearing housing to bound the bearing compartment, an air seal assembly defining a vent cavity along the bearing housing, wherein a mixing cavity is defined between the lubricant seal assembly and the air seal assembly, and wherein the bearing housing defines an airflow supply passage, an airflow vent passage and a scupper passage having respective fluid ports at different circumferential positions relative to the axis, the fluid port of the airflow vent passage fluidly coupled to the vent cavity, and the fluid ports of the airflow supply and scupper passages fluidly coupled to the mixing cavity. A method of sealing for a gas turbine engine is also disclosed.

Abstract: A gas turbine engine includes a plurality of rotatable components housed within a compressor section and a turbine section. A tap is connected to a location upstream of a downstream most location in the compressor section. The tap is connected to a heat exchanger. Downstream of the heat exchanger is a shut off valve and downstream of the shut off valve is a cooling compressor. The cooling compressor is connected to deliver cooling air through a chamber, and then to at least one of the plurality of rotatable components. The chamber is provided with at least one check valve configured to selectively allow flow directly from a more downstream location in the compressor section than the location upstream. The flow from the more downstream location has a higher pressure than a flow from the location upstream. There is a system for stopping operation of the cooling compressor. There is a control for closing the shut off valve.

Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. The turbine section includes a high pressure turbine comprising a plurality of turbine blades. The gas turbine engine includes a tap for tapping air that is compressed by the compressor, to be passed through a heat exchanger to cool the air, the cooled air to be passed to the plurality of turbine blades. A sensor is located downstream of a leading edge of the combustor, and is configured to measure a characteristic of the cooled air. A controller is configured to compare the measured characteristic to a threshold and control an operating condition of the gas turbine engine based on the comparison.

Abstract: A rotor blade for a gas turbine engine includes a blade extending from a root and a contoured tip portion at a first end of the blade. The first end is opposite the root. The contoured tip portion includes a first sloped region and a second sloped region. The second sloped region is steeper than the first sloped region, relative to a platform.