Abstract: A process of forming an air cooled turbine airfoil using a metal additive process, where the airfoil is formed by first producing a ceramic core having an internal cooling circuit shape, and then building up the airfoil over the ceramic core. The ceramic core is then leached away, and the outer surface of the airfoil is machined to remove rough surfaces formed by the metal additive process.

Abstract: An apparatus and a process for producing a shrouded centrifugal impeller where a rear hub opening is machined into the stock material so that hard to reach surfaces in the enclosed passages can be machined. When the hard to reach passages are machined to a final stage, the rear hub opening is closed using a process such as electron beam melting or electron beam welding to enclose the passages and form a single piece shrouded impeller.

Abstract: A method for designing an air cooled turbine airfoil includes selecting a number of different internal cooling air circuits, forming a ceramic core for each of the different cooling air circuits, forming a metal airfoil over each of the ceramic cores, leaching away the ceramic cores, mounting the airfoils in a stage of a turbine, passing a hot gas stream through the turbine, passing cooling air through each of the airfoils, and measuring a pressure and temperature differential across each of the airfoils to determine which cooling air circuit has the best performance.