Experimental Investigation of Airfoil Wake Clocking Impacts on Aerodynamic Performance in a Two Stage Turbine Test Rig

Abstract

This paper presents experimental findings on the effects of circumferential clocking of vanes and blades in a turbine test rig, based on a 1/3 scale model of the first two stages of the four stage Advanced Turbine System (ATS) turbine. The investigation was a collaborative effort among Siemens Westinghouse Power Corporation, The Ohio State University, and Florida Turbine Technologies, Inc. The objective of this experimental program was to investigate the effects of airfoil wake clocking and to explore ways to evaluate clocking feasibility during the design phase. Measurements obtained included inlet and exit total pressures and temperatures, turbine mass flow and shaft speed, airfoil leading edge temperatures, and inter-row endwall and airfoil surface static pressures and heat fluxes. Results presented herein focus primarily on the measured turbine performance based on inlet and exit pressures and temperatures. Results from the heat transfer measurements and analyses are not presented in this paper, but are the focus of another paper. Supporting aerodynamic analyses were conducted and results compared to the experimental results to confirm operating boundary conditions and provide input to uncertainty analyses. The results of these experiments and analyses validate the use of one and two-dimensional aerodynamic design approaches coupled with wake tracking to produce a “clockable” turbine; followed by the use of steady and unsteady 3D computational fluid dynamics (CFD) and experimental investigation to verify the 3D wake position, quantify the benefits, and further understand the flow physics.