Methods, apparatus, systems and articles of manufacture are disclosed. A shroud assembly of a gas turbine engine includes: a first shroud arm having a first end and a second end, the first end to couple to an outer wall and the second end to couple to a first shroud pad, and a second shroud arm having a first end and a second end, the first end to couple to the outer wall and the second end to couple to a second shroud pad, at least one of the first shroud pad or the second shroud pad to move radially outward toward the outer wall in response to a rotor blade contacting the at least one of the first shroud pad or the second shroud pad.

Methods, apparatus, systems and articles of manufacture are disclosed. A shroud assembly of a gas turbine engine includes: a first shroud arm having a first end and a second end, the first end to couple to an outer wall and the second end to couple to a first shroud pad, and a second shroud arm having a first end and a second end, the first end to couple to the outer wall and the second end to couple to a second shroud pad, at least one of the first shroud pad or the second shroud pad to move radially outward toward the outer wall in response to a rotor blade contacting the at least one of the first shroud pad or the second shroud pad.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.

A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.

A gas turbine engine for an aircraft includes an engine core including a first, lower pressure, turbine, a first compressor, and a first core shaft connecting the first turbine to the first compressor; and a second, higher pressure, turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor, and a fan located upstream of the engine core and including a plurality of fan blades extending from a hub. A turbine to fan tip temperature change ratio of a low pressure turbine temperature change to a fan tip temperature rise is in the range from 1.46 to 2.0.

A gas turbine engine for an aircraft includes an engine core including a first, lower pressure, turbine, a first compressor, and a first core shaft connecting the first turbine to the first compressor; and a second, higher pressure, turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor, and a fan located upstream of the engine core and including a plurality of fan blades extending from a hub. A turbine to fan tip temperature change ratio of a low pressure turbine temperature change to a fan tip temperature rise is in the range from 1.46 to 2.0.

Methods, apparatus, systems and articles of manufacture are disclosed to illustrate a clearance design process and strategy with CCA-ACC optimization for exhaust gas temperature (EGT) and performance improvement. In some examples, an apparatus includes a case surrounding at least part of a turbine engine, the at least part of the turbine engine including a turbine or a compressor. The apparatus further includes a first source to obtain external air; a second source to obtain cooled cooling air; a heat exchanger to control temperature of cooled cooling air; and a case cooler to provide active clearance control air to the case to control deflection of the case, wherein the active clearance control air is a combination of the external air and the cooled cooling air, the case cooler coupled to the heat exchanger using a first valve, the first valve triggered by a first control signal.

Methods, apparatus, systems and articles of manufacture are disclosed to illustrate a clearance design process and strategy with CCA-ACC optimization for exhaust gas temperature (EGT) and performance improvement. In some examples, an apparatus includes a case surrounding at least part of a turbine engine, the at least part of the turbine engine including a turbine or a compressor. The apparatus further includes a first source to obtain external air; a second source to obtain cooled cooling air; a heat exchanger to control temperature of cooled cooling air; and a case cooler to provide active clearance control air to the case to control deflection of the case, wherein the active clearance control air is a combination of the external air and the cooled cooling air, the case cooler coupled to the heat exchanger using a first valve, the first valve triggered by a first control signal.

Sealing arrangements and rotor assemblies are provided. A sealing arrangement includes a stationary component, a rotating component spaced apart from the stationary component. A clearance is defined between the stationary component and the rotating component. The sealing arrangement further includes a plurality of magnets embedded within the rotating component. The sealing arrangement further includes a brush seal having a frame and a plurality of magnetically responsive filaments. The plurality of magnetically responsive filaments each extending from the frame to a free end. The plurality of magnetically responsive filaments are attracted to the rotating component by the plurality of magnets. The plurality of magnetically responsive filaments at least partially covering the clearance, such that a flow of fluid across the clearance is restricted.

Sealing arrangements and rotor assemblies are provided. A sealing arrangement includes a stationary component, a rotating component spaced apart from the stationary component. A clearance is defined between the stationary component and the rotating component. The sealing arrangement further includes a plurality of magnets embedded within the rotating component. The sealing arrangement further includes a brush seal having a frame and a plurality of magnetically responsive filaments. The plurality of magnetically responsive filaments each extending from the frame to a free end. The plurality of magnetically responsive filaments are attracted to the rotating component by the plurality of magnets. The plurality of magnetically responsive filaments at least partially covering the clearance, such that a flow of fluid across the clearance is restricted.