Impact of Inlet Conditions on TVF Exit Flow Field

Abstract

The drive towards lightweight, more efficient engine architectures leads to the development and improvement of key aircraft engine components. The Turbine Vane Frame (TVF) can be seen as an evolution of the Turbine Center Frame (TCF), combining its structural and aerodynamic purposes with the function otherwise provided by the first stage turbine inlet guide vanes. Therefore, the TVF needs to smoothly guide the flow over the radial offset between high-pressure and low-pressure turbine stages, provide shrouded paths for oil lines, and impart to the flow the turning required by the following low pressure turbine stage. The expected beneficial effects on the engine include reduced weight, cost, and fuel burn. The key relevance of this component makes a broad, low-tier approach to its study highly desirable. The HighSpeed Wind Tunnel (HSWT) at the Technical University of Graz delivers excellent opportunities to explore the design space for Turbine Vane Frames. This paper deals with the impact of several important design parameters on the TVF. An engine relevant TVF configuration is replicated in an annular sector cascade test rig. The test rig is operated at relevant Mach number and turbulence level. Representative inlet flow is achieved through flow conditioning. Aerodynamic data is collected with five-hole probe and hot wire anemometry techniques. The insights offered by flow visualization and numerical computations are furthermore leveraged. Particular attention is given to the flow features at the TVF exit.