Cooling Performance of Additively Manufactured Pin Fins in Stacked Microchannels for the Inside-Out Ceramic Turbine Shroud-Cooling Ring

Abstract

The Inside-out ceramic turbine (ICT), a novel microturbine rotor architecture, has an air-cooled ring which keeps its composite rotating structural shroud within operating temperature. The cooling ring must achieve a significant radial temperature gradient with a minimal amount of cooling. The cooling ring is made through additive manufacturing, which opens the design space to tailored cooling geometries. Additively manufactured pin fin heat transfer enhancers are explored in this work to assess whether they hold any significant performance benefit over current rectangular cross-section open channels. Experimental friction factors and Nusselt numbers were determined for small, densely-packed pin fins over an asymmetrical thermal load. Results indicate that pressure loss is similar to what can be expected for additively manufactured pin fins, whereas heat transfer is lower due to the extremely tight streamwise pin spacing, in both in-line and staggered pin configurations. A design study presented in this paper suggests that pin fins are beneficial to an ICT for reducing cooling mass flow rate up to 40 %, against an increase in cooling ring mass of roughly 50%.

Design and characterization of a miniaturized low inertia and low viscous friction magnetorheological clutch using 3D metal printing for human-robot applications

“…AM allows to dramatically reduce costs when used for small production and is very versatile (Frazier, 2014). Metal 3D printing is even starting to be used for commercial parts in a few cutting-edge fields, mainly for aerospace (Gisario et al, 2019; Tepylo et al, 2019), for example, for turbine cooling rings (Dubois et al, 2021). Metal AM can also be profitable for complex parts impossible to make with conventional machining (Shamvedi et al, 2018).…”