CFD Study to Analyze the Behavior of Secondary Flow Using Fillets

Abstract

Secondary flow are a series of vortex created at the leading edge of the blade. These vortexes decrease the efficiency of the turbine by creating a non-uniform flow which will pass to successive blade stages. The secondary flow also causes heat transfer problems by moving hot air from the center of the passage to the endwall. Some methods are being studied to weak these vortexes including adding fillets to the leading edge of the blade. For this article a CFD study was perform using four different fillets to examine the behavior of the vortex by including the fillets. The design fillets were not able to eliminate the vortex and flow separation but the tall fillets seemed to increase the velocity at the passages. While the small area fillets seemed to worsen the flow separation. Key Terms― CFD, Horseshoe Vortex, Secondary Flow, Turbine