Numerical investigation on dimpled tube effects on internal cooling performance of turbine blades

Abstract

This research examines how modified surfaces may improve the internal cooling performance of advanced turbine blades. A few correlations are established for three different dimpled tubes to estimate their heat transfer coefficient. To save computational expenses, these correlations are used in a reduced conjugate heat transfer (RCHT) scheme. Using a numerical simulation with the k- ω SST turbulence model, the formulation is validated by comparison with numerical and experimental data for a smooth tube. The scheme is applied to the advanced C3X turbine blades to asses the merit of the new design. The research finds that dimples in the cooling passage may reduce the temperature on the blade surface up to 130 K and increase the heat flux on the blade surface up to 50 %. Teardrop dimples offered the best performance in enhancing heat transfer. Additionally, they reduced the average temperature on the midspan of the C3X blade by up to 19.8 %. The study demonstrates the advantages of employing modified surfaces to improve blade internal cooling performance. It also confirms the validity of the RCHT assumption, which can simplify simulation in comparable test cases.