Turbine blade, more particularly turbine nozzle vane, for gas turbine engines

Claim 1

In a turbine blade, particularly a turbine nozzle vane, for gas turbine engines, including a structurally supportive metallic core, a ceramic blade jacket encasing said core so as to form a space therebetween, at least one spanwise-oriented cooling air duct in said space, and where inner and outer blade shroud means for suspending the turbine vane from structural inner and outer casing components for centered positioning and for limited radial and axial thermoelastic flexibility; the improvement comprising: (a) said blade jacket being inserted into recesses in the inner and outer blade shroud means and being subjected to compressive prestressing in the spanwise direction between the shroud means; (b) first and second sleeve-like components being acted upon by concurrent forces to produce said compressive stress and being welded to the metallic core, each said component engaging, with its end pointing away from the weld and facing the core, in a corresponding recess in, respectively, the inner and outer shroud means; (c) a spanwise oriented heat shield being arranged in the space between the blade core and the jacket; a cooling air duct being enclosed between the shield and the blade core; (d) said structural arrangement of the blade maintaining the compressive prestressing of the blade jacket produced during assembly in the operating condition, said metallic blade core being a material having a moderate coefficient of thermal expansion is selected, said metallic inner and outer shroud means and the inner and outer metallic sleeve-like components being formed of materials having a higher coefficient of thermal expansion; and the highly thermally stressed or thermally resistant ceramic blade jacket being formed of a material of average coeffecient of thermal expansion.