COOLING EFFECTIVENESS OF ADDITIVE-MANUFACTURED INTERNAL STRUCTURE WITHIN A DOUBLE WALL COOLING SYSTEM

An internal structure that additively manufactured (AM) within a double-wall cooling system for gas turbine applications was proposed and evaluated for its ability to increase cooling efficiency. Polymer AM specimens were fabricated using a Biot number similarity approach with actual gas turbine materials. Three types of double wall specimens were manufactured: a standard double wall cooling (baseline) case, a double wall cooling with pin-fin structure (pin), and a double wall cooling with a cube lattice structure(cube). Flow pattern analysis was conducted to examine the effect of the cube lattice on the internal structure of the double wall cooling system, and static pressure was measured in each chamber. An infrared thermography method was used to measure overall cooling effectiveness on the specimen surface, and each case was tested at blowing ratios (M=0.4, 0.6, and 0.8). Compared to the baseline case, the cube lattice structure improved cooling effectiveness by 3.36% at M=0.4, the most significant improvement of 4.33% at M=0.6, and 2.71% at M=0.8. These findings suggest that the use of a cube lattice structure that produced by AM can effectively enhance the cooling performance in double wall cooling system for gas turbine hot parts.