Composite Casting/Bonding Construction of an Air-Cooled, High Temperature Radial Turbine Wheel

This paper addresses the design and fabrication of a high temperature radial turbine wheel constructed by a composite casting/bonding technique. Areas discussed include aerodynamic analyses; the design of blade internal passages for cooling the dual turbine wheel (star wheel and exducer) in a 2800°F (1810K) TIT service environment; the procedure for producing the castings; and the fabrication of cooling passages by a “split blade” technique in which the internal details are constructed independently from sheet metal and sintered powder and are subsequently HIP-bonded within the wheels.