ASCENT Project 56: Reduced Fuel Burn through Double-Wall Cooling of Turbine Airfoils Made Possible through Additive

Sponsor: Federal Aviation Administration

Collaborators: Pratt & Whitney

Gains in cooling performance of cooled turbine airfoils have a direct impact on the efficiency of turbine engines and therefore is the subject of much development. Today, many cooling designs for turbine airfoils use complex micro-channels placed in the wall of the airfoil to extract heat, which is otherwise known as double-wall cooling. The geometric complexities of the micro-channels, however, are limited by the casting process for these relatively small features. One approach to manufacture these complex channels is the use of metal-based additive manufacturing (AM), which is also known as laser powdered bed fusion. AM has begun to see many uses in the gas turbine industry, particularly because of the new design space enabled by this new fabrication method. However, not only does AM open up new design opportunities, but it also provides a quick turnaround from design concept to manufactured component relative to the traditional casting process.

The impact of this work is twofold: i) to develop an optimized micro-channel (double-wall) cooling design that will result in reduced cooling air but maintain turbine airfoil durability; and ii) to assess the viability of using additive manufacturing to print complex double-wall cooling designs. While optimization methods have been employed to develop new cooling technologies, the success of these technologies is only made possible if the designs can be made feasible. Thole’s previous research, has shown that it is feasible to use optimization methods to develop unique cooling features and although this previous research was not done for airfoil cooling, a similar methodology could be employed for this project.