X-wire investigation of turbulent flow in simulated additively manufactured turbine blade cooling channels.
Gas turbine blades may be additively manufactured (AM) using processes such as direct metal laser sintering (DMLS) to create more complex shapes and produce more effective cooling than otherwise feasible with traditional manufacturing methods. Additionally, the AM process causes the development of unique surface roughness patterns, which are very different from the types of roughness used to develop traditional correlations for friction losses and convection. In previous work, a method was developed for measuring flow losses in scaled channels using 3-D printed surfaces of both real AM roughness and surfaces employing analog roughness elements. For this study, detailed measurements of velocity profiles are performed using x-array hot-film anemometry inside the simulated AM cooling channels. The turbulent flow characteristics of the measured profiles and measured friction loss coefficients demonstrate behaviors different from sand-grain surfaces described using traditional correlations.