Publication Date
2025
Document Type
Thesis
Committee Members
Mitch Wolff, Ph.D. (Advisor); John Clark, Ph.D. (Committee Member); Christopher Marks, Ph.D. (Committee Member)
Degree Name
Master of Science in Mechanical Engineering (MSME)
Abstract
Low-pressure turbines (LPTs) play a crucial role in fuel efficiency and thrust generation of aero-engines. Traditional LPT designs, however, involve multiple stages and numerous blades, resulting in increased weight and manufacturing costs. The challenge of modern- day researchers is to reduce the weight and cost but maintain the high efficiency of LPTs. To address this, one approach is to increase the aerodynamic loading of individual blades, reducing the blade count. However, this can lead to increased secondary losses caused by flow separation, particularly in the endwall regions. This research focuses on optimizing the blade profile at the junction with the endwall to reduce these losses. A binary evolutionary genetic algorithm is used to design an improved contoured blade geometry that minimizes total pressure loss across the blade row. By modifying user-defined parameter bounds, two optimization routines produced a contour profile with a high and low stagger angle. The two designs were experimentally validated in a low-speed linear-cascade wind tunnel environment, and comparisons between the computational predictions and the experimental measurements are presented. Experimentally, the total passage loss was reduced by 15.2% and 20.2% by each design. Results from the genetic algorithm suggest that an increased blend height would prove efficient for reducing pressure loss. A secondary study was completed to investigate the benefits of increased blend height with one of the selected geometries. Discrepancies between the CFD and experimental analysis were found to stem from the complex flow dynamics. This led to inaccurate modeling of flow physics at increased blend heights. Although some flow physics were not accurately modeled, an improvement in total pressure loss is experimentally presented with increased blend heights. The observed reduction in total pressure loss coefficient confirms the performance gains and demonstrates the effectiveness of the optimization framework in improving the high-lift LPT blade design.
Page Count
71
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
2025
Copyright
Copyright 2025, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
