A wind turbine blade is described having a de-icing system which is arranged to heat at least a portion of the leading edge of the wind turbine blade, to prevent the formation of ice on the blade, or to remove any existing surface ice. The de-icing system comprises insulated flow channels which are arranged to circulate a heated fluid from a heating element to the tip end of the blade, and to de-ice the blade leading edge starting from the tip end towards the root end of the blade. The de-icing system is arranged to operate in the outboard portion of the blade, where the de-icing effect provides the most benefits to turbine operation. Further features of the de-icing system include an improved mounting arrangement of the de-icing system, an improved tip end configuration of the de-icing system, and providing portions of the de-icing system as double-walled inflatable insulating tubes.

The disclosure describes articles and techniques that include an airfoil having a hybrid coating system to provide improved particle impact resistance and improve CMAS attack resistance on the pressure side of the airfoil and improved thermal load protection on the suction side of the airfoil. An example article for a gas turbine engine may include a substrate, and a hybrid environmental barrier coating (EBC) including a relatively dense EBC layer on a first portion of the substrate and a relatively porous EBC layer on a second portion of the substrate, where the first portion of the substrate is different from the second portion of the substrate, and wherein at least a portion of the relatively porous EBC layer overlaps at least a portion of the relatively dense EBC layer in an overlap region.

A method of cooling a wind turbine. A cooling system is operated with a first setpoint temperature to cool the wind turbine over a first period. The method comprises measuring a temperature of the wind turbine over the first period to obtain temperature measurements; allocating each of the temperature measurements to a temperature range, wherein one or more of the temperature ranges are critical temperature ranges; and for each critical temperature range, comparing a parameter indicative of a number of the temperature measurements allocated to the critical temperature range with a threshold; selecting a second setpoint temperature on the basis of the comparison(s); and operating the cooling system with the second setpoint temperature over a second period. An equivalent method is also disclosed in which a power setting of the wind turbine is changed on the basis of the comparison(s).

The disclosure describes articles and techniques that include an airfoil having a hybrid coating system to provide improved particle impact resistance and improve CMAS attack resistance on the pressure side of the airfoil and improved thermal load protection on the suction side of the airfoil. An example article for a gas turbine engine may include a substrate, and a hybrid environmental barrier coating (EBC) including a relatively dense EBC layer on a first portion of the substrate and a relatively porous EBC layer on a second portion of the substrate, where the first portion of the substrate is different from the second portion of the substrate, and wherein at least a portion of the relatively porous EBC layer overlaps at least a portion of the relatively dense EBC layer in an overlap region.

A method for accurately producing the drilled hole in a wall of a component fabricated by investment casting process, such as for use in a blade or steam turbine includes the following steps. The 3D data of actual component is obtained from the measurements or from the numerical simulation. The actual model and the ideal model are aligned and compared, a series of cutting planes are given to establish a series of 2D cross-sections of the actual and ideal models after registration. Each cross-section is dispersed into discrete points, the distance between each corresponding points are calculated and formed into 2D displacement. The accurate parametric model consisting of the depth, hole center, and the nominal vector is obtained on the basis of considering the deviations in geometrical and positional values. The drilled hole is then produced according to the corrected parametric drilled-hole geometrical and positional value.

A wind turbine blade is described having a de-icing system which is arranged to heat at least a portion of the leading edge of the wind turbine blade, to prevent the formation of ice on the blade, or to remove any existing surface ice. The de-icing system comprises insulated flow channels which are arranged to circulate a heated fluid from a heating element to the tip end of the blade, and to de-ice the blade leading edge starting from the tip end towards the root end of the blade. The de-icing system is arranged to operate in the outboard portion of the blade, where the de-icing effect provides the most benefits to turbine operation. Further features of the de-icing system include an improved mounting arrangement of the de-icing system, an improved tip end configuration of the de-icing system, and providing portions of the de-icing system as double-walled inflatable insulating tubes.

A cooled gas turbine engine component comprises a wall having first and second surfaces. The second surface has a plurality of recesses and each recess has a planar upstream end surface arranged so that it hangs over the upstream end of the recess. Each recess has a depth equal to the required depth plus the thickness of the thermal barrier coating to be deposited. The wall has a plurality of angled effusion cooling apertures extending from the first surface towards the second surface. Each effusion cooling aperture has an inlet in the first surface and an outlet in the end surface of a corresponding one of the recesses in the second surface. Each recess has smoothly curved transitions from the end surface and side surfaces to the second surface. Blocking of the effusion cooling apertures by thermal barrier coating is reduced.

A method for accurately producing the drilled hole in a wall of a component fabricated by investment casting process, such as for use in a blade or steam turbine includes the following steps. The 3D data of actual component is obtained from the measurements or from the numerical simulation. The actual model and the ideal model are aligned and compared, a series of cutting planes are given to establish a series of 2D cross-sections of the actual and ideal models after registration. Each cross-section is dispersed into discrete points, the distance between each corresponding points are calculated and formed into 2D displacement. The accurate parametric model consisting of the depth, hole center, and the nominal vector is obtained on the basis of considering the deviations in geometrical and positional values. The drilled hole is then produced according to the corrected parametric drilled-hole geometrical and positional value.