DELAYED DETACHED EDDY SIMULATION OF A FULL 3-DIMENSIONAL HIGH-PRESSURE TURBINE STAGE, PART I: FLOW TOPOLOGY

In this work, the flow inside a high pressure turbine (HPT) stage is studied with the help of a high-fidelity delayed detached eddy simulation (DDES) code. This work intends to study the flow topology in the HPT stage. There are two motivations for this work: On the one hand, high pressure turbines operates at both transonic Mach numbers and high Reynolds numbers, which imposes a challenge to modern computational fluid dynamics (CFD), especially for scale-resolved simulation methods. An accurate and efficient high-fidelity CFD solver is very important for a thorough understanding of the flow physics and the design of higher-efficient HPT. On the other hand, the wake vortex shedding and tip-leakage flow are important origins of turbine losses and unsteadiness. Built on our previous DDES simulations of HPT vane and stage, this work further investigates the flow in a full 3-dimension HPT stage. The flow topology in the HPT stage is delineated by Q-criterion iso-surfaces. The development of the horseshoe vortex and its interaction with induced vortex and wake vortex is discussed. The wake vortex transportation especially its interaction with the rotor horseshoe vortex is investigated. The flow structures in the tip clearance region are also revealed.