INVESTIGATION OF SECONDARY FLOW LOSSES IN LOW PRESSURE TURBINES WITH A NOVEL ENDWALL FEATURE

Emrullah YILMAZ and Oguzhan MURAT

The phenomenon of secondary flows has been a significant subject of study in turbomachinery for decades. Scientists and engineers have conducted numerous experimental and numerical investigations to understand and optimize the losses caused by secondary flows. Most frequently studied methods include endwall contouring. However, with the recent advances in manufacturing techniques, a wider range of options is now available. In this study, three different endwall features are studied using 3D steady-state RANS simulations to examine their influence on secondary flow losses. The first two are conventional techniques, namely riblets and fillets placed on the hub. The third one explores a novel idea that incorporates a channel embedded inside the hub. This channel opening starts at the passage inlet and merges back with the passage at the exit. It is observed in the kinetic energy loss coefficient that the novel channel method outperforms the conventional endwall contouring methods, reducing the magnitude of the core secondary flow by about 32 percent compared to the baseline (smooth) case.

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