Experimental and numerical investigation of effusion cooling flow and heat transfer for a gas turbine blade leading edge with an internal swirl chamber and a Diamond-TPMS structured wall

Abstract

To meet the increasing thermal load and efficiency demands of advanced heavy-duty gas turbines, enhanced cooling strategies for turbine blade leading edges are required. This study proposes and investigates a composite cooling concept integrating internal swirl chamber with a Diamond-type Triply Periodic Minimal Surface (TPMS) effusion wall. Four leading-edge cooling configurations are examined using experiments and conjugate heat transfer simulations: a jet impingement–film cooling model, a ridged swirl–film cooling model, and ridged swirl–Diamond TPMS effusion models with baseline and high porosities. Infrared thermography experiments are conducted to evaluate overall cooling effectiveness at blowing ratios of 0.67, 1.34, and 2.0, while numerical simulations are employed to elucidate the associated flow and heat transfer mechanisms. The results indicate that ridge-induced swirl significantly enhances internal flow mixing and temperature uniformity, resulting in higher overall cooling effectiveness. Replacing discrete film holes with Diamond-TPMS effusion structures fundamentally changes the external cooling behavior, shifting from localized high-momentum jets to distributed low-momentum effusion, which improves surface coverage continuity and reduces temperature gradients. Furthermore, increasing effusion porosity induces a transition in the dominant cooling mechanism from internal–external synergistic cooling to externally effusion-dominated cooling. The high-porosity ridged swirl–Diamond TPMS effusion model exhibits the best performance at high blowing ratios, achieving up to 21.5% improvement in area-averaged overall cooling effectiveness and more than 50% reduction in internal coolant pressure loss relative to the impingement–film baseline at BR = 2.0.