Effect of Porosity and Injection Ratio on the Performance of Transpiration Cooling through Gyroids †

Abstract

This paper presents experimental measurements of adiabatic effectiveness for three transpiration cooling porosities ( (Formula presented.) 0.3, 0.4, and 0.5) constructed from gyroid lattice structures. To the authors’ knowledge, this is the first use of a Triply Periodic Minimal Surface (TPMS) function to produce transpiration test coupons of varying porosity. Polymer gyroid lattice structures were successfully printed using Stereolithography (SLA) down to (Formula presented.) 0.3 for a print resolution of 25 microns and unit cell size of 2 mm. Cooling performance was measured in a small-scale wind tunnel. High-resolution Infrared Thermography was used to determine wall temperatures downstream of the porous section. When tested at both common blowing ratios ( (Formula presented.) = 0.029, 0.048, and 0.062) and common injection ratios ( (Formula presented.) = 0.010, 0.017, and 0.022) the cooling performance was found to be dependent on porosity for constant (Formula presented.) but not for constant (Formula presented.). Having determined (Formula presented.) as the more important parameter for comparison, results are presented alongside transpiration and effusion data from literature.