Internal Convective Heat Transfer in a Real Engine Component: A Comparison Between Pin-Fins and Kagome Lattice

The capabilities and accuracy of additive manufacturing processes have experienced remarkable advancements in recent years, with no signs of slowing down. As a result, there is increasing interest from researchers in the gas turbine industry regarding its potential application in cooling system designs. This study presents a comparative analysis of the heat transfer capabilities of pin-fins and Kagome turbulators applied to the trailing edge of a turbine vane. A transient experimental measurement technique was employed to investigate the internal convective heat transfer performance of both cooling configurations. The experimental setup involved the use of surface temperature measurements during transient heat flux conditions, and the internal convective heat transfer coefficient was determined using a numerical procedure that ends with a linear regression method applied to the transient thermal response. Since the pressure drop across each array of turbulators is another important performance parameter, their friction factor was also estimated during a dedicated test campaign. The investigated flow Reynolds numbers range from 3000 to 14,000. These values allow the authors to provide a deeper understanding of the latticework structures’ performances in Reynolds numbers range typical of applications in a gas turbine vane trailing edge. Experimental results indicate that Kagome turbulators provide a slight improvement (about 2%) of the thermal performance with respect to the pin-fin geometry, thanks to the increased wet area and a lower friction factor especially at higher Reynolds number conditions, with a reduction of approximately 8%.