Apparatus and method for modifying a geometry of a turbine part

A hydraulic turbine, comprising:

• a stay ring;
• at least one stay vane attached to the stay ring;
• and
• a stay vane extension having a shell assembly defining an inner cavity, a polymer casting positioned within the inner cavity, and a core positioned within the inner cavity, the core comprising a plurality of hollow members for circulating a fluid therethrough to help facilitate cooling of the polymer casting, the stay vane extension being attached to the at least one stay vane, the shell assembly further comprising a plurality of stiffeners positioned within the inner cavity and at least one injection port for injection of the polymer casting into the inner cavity, the plurality of stiffeners configured to stiffen the shell assembly during injection of the polymer casting.

A method of modifying a geometry of a part of a hydraulic turbine, comprising:

• positioning an outer shell adjacent to a part of the hydraulic turbine, the outer shell comprising a composite material, the composite material comprising polymeric material, the outer shell further comprising a core positioned within an inner cavity thereof, the core further comprising a plurality of stiffeners and a plurality of hollow members;
• attaching the outer shell to the part;
• injecting a polymer casting into an injection port on the outer shell in fluid communication with the plurality of hollow members of the core of the inner cavity, the plurality of stiffeners configured to stiffen the shell assembly during injection of the polymer casting;
• and
• circulating a fluid through the plurality of hollow members to help facilitate cooling of the polymer casting.