Ceramic matrix composite articles include, for example a first plurality of plies of ceramic fibers in a ceramic matrix defining a first extent, and a local at least one second ply in said ceramic matrix defining a second extent on and/or in said first plurality of plies with the second extent being less than said first extent. The first plurality of plies has a first property, the at least one second ply has at least one second property, and said first property being different from said at least one second property. The different properties may include one or more different mechanical (stress/strain) properties, one or more different thermal conductivity properties, one or more different electrical conductivity properties, one or more different other properties, and combinations thereof.

Turbine engine (80) components, such as blades (92), vanes (104, 106), ring segment 110 abradable surfaces 120, or transitions (85), have furcated engineered groove features (EGFs) (403, 404, 418, 509, 511, 512) that cut into the outer surface of the component's thermal barrier coating (TBC). In some embodiments, the EGF planform pattern defines adjoining outer hexagons (560, 640, 670, 690, 710). In some embodiments, the EGF pattern further defines within each outer hexagon (560, 640, 670, 690, 710) a planform pattern of adjoining inner polygons (570, 580, 590, 600, 610, 680, 682, 700, 702, 704, 705, 720). At least three respective groove segments (509, 511, 512) within the EGF pattern (506, 507, 508) converge at each respective outer hexagonal vertex (510, 564) or inner polygonal vertex (574, 564, 604, 614) in a multifurcated pattern, so that crack-inducing stresses are attenuated in cascading fashion, as the stress (σ.sub.A) is furcated (σ.sub.B, σ.sub.C) at each successive vertex juncture.

An embodiment of a torch ignitor system for combustor of a gas turbine engine includes a torch ignitor, the torch ignitor having a combustion chamber oriented about an axis, the combustion chamber having axially upstream and downstream ends defining a flow direction through the combustion chamber, along the axis. The torch ignitor system also includes a cap defining the axially upstream end of the combustion chamber and oriented about the axis, wherein the cap is configured to receive a fuel injector and at least one glow plug, a tip at a downstream end of the combustion chamber, and a passage for pressurized oxygen containing gas passing through the cap from an exterior of the combustion chamber and in fluid communication with the combustion chamber. An embodiment of a method for starting a gas turbine engine is also disclosed.

A method for controlling a gas turbine assembly includes: a compressor in which compression of the outside air occurs for producing a flow of compressed air; a sequential combustor including a first combustor, in which combustion of a mixture of fuel and compressed air arriving from the compressor occurs for producing a flow of hot gasses, and a second combustor which is located downstream of the first combustor and in which combustion of a mixture of fuel and hot gasses arriving from the first combustor occurs; an intermediate turbine in which a partial expansion of the hot gasses arriving from the first combustor occurs; and a second combustor in which combustion of a mixture of fuel and hot gasses arriving from the intermediate turbine occurs; the method further includes, on a start-up transient operating phase of the gas turbine assembly, the step of controlling the fuel mass flow-rate supplied to the first and/or the second combustor on the basis of the flame temperature inside the first combustor.

A turbine blade disposed along a radial direction of a turbine includes: an airfoil portion positioned in a fluid flow passage of the turbine; and a shroud portion positioned on an inner side or an outer side of the airfoil portion in the radial direction, and having an opening with which an end portion of the airfoil portion is to be engaged. A clearance is formed between a wall surface forming the opening of the shroud portion and an outer peripheral surface of the end portion of the airfoil portion. The wall surface of the shroud portion and the outer peripheral surface of the airfoil portion are joined to each other. At least one of the shroud portion or the airfoil portion has a cooling hole formed thereon, the cooling hole having an opening into the clearance and being configured to supply the clearance with a cooling fluid.

A cooling system includes: a high pressure bleed line configured to bleed high pressure compressed air from a first bleed position of a compressor and to send the air to a first hot part; a low pressure bleed line configured to bleed low pressure compressed air from a second bleed position of the compressor and to send the air to a second hot part; an orifice provided in the low pressure bleed line; a connecting line configured to connect the high pressure bleed line and the low pressure bleed line; a first valve provided in the connecting line; a bypass line configured to connect the connecting line and the low pressure bleed line; and a second valve provided in the bypass line.

A system for operating a gas turbine engine to mitigate the risk of ice formation within the engine, the system including a controller arranged to control at least one operational parameter of the engine such that the engine operates in a safe zone; and, a processor configured to function as a determining module to make a comparison between values and determine whether the engine is operating within a safe zone based on at least a core pressure parameter relating to the pressure within the engine and a core temperature parameter relating to the temperature within the engine, wherein the safe zone is defined by the product (multiplied) of the core pressure parameter and core temperature parameter being above a safe threshold.

A mounting bracket for mounting an accessory to a gas turbine engine comprises a space frame structure. The space frame structure comprises a plurality of struts joined to one another at nodes.

A turbine arrangement for a gas turbine engine comprising a turbine shaft. An axial array of turbine rotors, having a first axial end and a second axial end. A drive arm coupled between the turbine shaft and the first axial end. A measurement system arranged to measure a parameter of the turbine arrangement, the measurement system positioned at the second axial end. The parameter may be rotational speed.

The leading edge, the trailing edge, or both may be axially offset for a portion of the airfoils in a disk. By offsetting the airfoils, the downstream wake energy to the next stage of airfoils may be decreased. By staggering airfoils which are offset with airfoils that are not offset, the wake shapes from the airfoils may be out of phase and will not excite the downstream airfoils as much as conventional systems. This may decrease vibration and associated vibratory stresses in the system.