The Design, Analysis and Test of a Unique Gas Turbine Scroll for the F-35, Joint Strike Fighter

The design of the APU (Auxiliary Power Unit) for the F-35 JSF (Joint Strike Fighter) focused on minimizing size and weight while meeting stringent performance goals. To help realize that goal, a unique turbine scroll was designed. The scroll design delivers air from the combustor to the turbine inlet with minimal loss and flow distortion while minimizing design space. CFD (Computational Fluid Dynamics) results of scroll total pressure loss and exit peripheral distribution of total pressure, Mach number, and flow angle are presented. Rig tests were utilized for measuring and validating the computed total pressure and Mach number distributions around the periphery of the scroll exit. Comparisons of the CFD simulations and test data indicate strong correlation in values of average total pressure loss, local total pressure loss and Mach number around the exit periphery.