Session: 32-07 Loss Reduction for Axial Turbines

Submission Number: 178159

Aerodynamic Characterization of High-Lift, High-Work Low-Pressure Turbine Blades in an Annular Cascade 

This work presents the results and methodology from an experimental and computational campaign focused on a comprehensive aerothermal characterization of a set of high-lift, highly loaded LPT blades meant to push the design boundary for modern LPTs. The experimental setup utilizes a pressure-driven wind tunnel flowing through a full annular cascade test section with a downstream vacuum tank enabling engine representative flow conditions, with Reynolds number ranging from 75,000 to 135,000 and a rotor outlet Mach number of .78. The test section contains 3 different blade design iterations arranged in a rainbow configuration each with a work coefficient of 2.80, and Zweifel coefficients ranging from 1.32 to 1.78. A flow-conditioning gauze is employed to enable stationary testing of the rotor blades in their relative frame of reference. The blades' aerothermal performance was quantified through detailed measurements of the blades' surface loading, exit flow angle and Mach distribution, and overall loss generation. Additional measurement techniques were employed to identify flow structures including oil visualization to characterize secondary flow development and high-frequency hot wire and dynamic pressure transducer traverses for gathering frequency spectra data. An in-depth characterization of the blade’s inlet flow field was also completed to anchor the cascade’s inlet boundary conditions for the loss coefficient calculation and a CFD simulation of the entire annular cascade. The experimental results and CFD simulation are compared to evaluate the effectiveness of the computational approach for loss prediction. This combined experimental and computational campaign provides a valuable dataset for the continued development of high-lift, high-work LPT blades.

Presenting Author: Aaron Hammond Purdue University

Presenting Author Biography: Aaron Hammond received his B.S. in Aerospace Engineering from Georgia Institute of Technology and his M.S. in Mechanical Engineering from Purdue University. His background spans both industry and academic research in turbomachinery, including experience in rocket engine turbomachinery development and testing, as well as low-pressure turbine aerodynamics for aircraft propulsion. His current research focuses on the application of flow control techniques to enhance the performance of low-pressure turbine stages.

Authors:

Aaron Hammond Purdue University
Alvaro Malaga Olay Purdue University
James Twaddle Purdue University
Hunter Nowak Purdue University
John P. Clark Air Force Research Laboratory
Lukas Benjamin Inhestern Purdue University
Guillermo Paniagua Purdue University