Hollow fluid cooled turbine blades

Claim 1

A hollow fluid cooled turbine blade comprising a root, a platform and an aerofoil, the aerofoil having at least two longitudinally extending passages for the flow of cooling fluid, at least one turning passage where the cooling fluid is turned from the first longitudinally extending passage into the second longitudinally extending passage, a wall being positioned between and separating the longitudinally extending passages, said wall having an aerodynamically shaped end portion adjacent said turning passage, said aerodynamically shaped end portion of said wall being arranged at an angle with respect to the remainder of said wall to increase the turning radius and said aerodynamically shaped end portion of said wall extending towards a second wall defining an opposing boundary of said first passage, a turning vane having a relatively large turning radius being spaced from said aerodynamically shaped end portion of said wall to define a passage therebetween, said passage between said aerodynamically shaped end portion of said wall and said turning vane converging in the direction of flow from said first longitudinally extending passage to said second longitudinally extending passage, said turning vane extending around said aerodynamically shaped portion of said wall towards said second longitudinally extending passage so as to direct cooling fluid flowing from said first passage into said second passage through said converging passage formed between said aerodynamically shaped end portion of said wall and said turning vane substantially parallel to said wall, said turning vane directing the cooling fluid flowing around said turbine vane substantially parallel to the cooling fluid leaving said converging passage so as to reduce separation of the boundary layer of the cooling fluid from said wall in order to reduce pressure losses in said turning passage.