TPMS-enabled compound cooling design for enhanced conjugate heat transfer in turbine vane applications

As turbine inlet temperatures continue to increase, conventional pin-fin-based cooling systems face increasing thermal-hydraulic demands, particularly when coupled with external film cooling. This study investigates a conjugate compound-cooling configuration that integrates a Gyroid triply periodic minimal surface (TPMS) structure into the internal channel. Eight numerical models were developed to compare two representative Gyroid unit-cell scales against matched pin-fin references under both forward and reverse film injection. Under forward injection, the area-averaged overall cooling effectiveness of the compact TPMS configuration increases from 0.64 to 0.72 as the blowing ratio rises from 1.0 to 2.5, yielding a 3.22%–9.09% improvement over the matched pin-fin baseline. Regarding pressure loss, sparse TPMS layouts exhibit comparable or lower penalties, whereas compact layouts incur a 21.6%–40.6% increase. Furthermore, a CO₂-concentration-weighted centroid analysis reveals that the vertical position of the coolant distribution is highly dependent on configuration and operating conditions. Under forward injection, the compact TPMS centroid is generally slightly farther from the wall than that for its pin-fin counterpart; conversely, under reverse injection, it resides closer to the wall at BR ≥ 1.5. Ultimately, the thermal-hydraulic performance of the investigated TPMS structures is strongly governed by unit-cell scale, injection direction, and blowing ratio, rather than exhibiting a universal reduction in coolant-centroid height.