Date of Award

2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Aerospace Systems Engineering

Committee Chair

Phillip Ligrani

Committee Member

John Bennewitz

Committee Member

Kirk Boehm

Research Advisor

Phillip Ligrani

Subject(s)

Turbomachines--Blades--Aerodynamics, Turbomachines--Blades--Fluid dynamics, Heat--Transmission

Abstract

Considered within the present investigation are the extremity end of a transonic turbine airfoil with coolant films and a squealer rim. The employed film hole arrangements are denoted D5U and D9. The D5U arrangement is comprised of five film cooling holes located on the upper pressure side of the blade. The D9 arrangement involves the D5U supplied coolant stream as it interacts with coolant also supplied by four D4D holes located along the downstream portion of the upper pressure side of the blade, and with coolant also supplied by a single dusting hole located within the upstream portion of the blade tip recess region. To illustrate the different film cooling phenomena which are present, and the different film interactions which are present, considered are distributions of surface adiabatic film cooling effectiveness, and surface heat transfer coefficient ratios. These are provided along the extremity end of the turbine airfoil as local, spatially-resolved distributions, as spatially-averaged distributions, and as line-averaged distributions. Correlation equations are determined for spatially-averaged adiabatic film cooling effectiveness, and spatially-averaged surface heat transfer coefficient ratios in the form of power law equations and linear equations. Different magnitudes and signs of the coefficients associated with these equations characterize different types of phenomena associated with film cooling. Of particular focus are differences between D5U and D9 performance characteristics which result from the absence of interactions or the presence of interactions with films from other surface locations. For example, correlation equation coefficients indicate the frequent presence of partial or significant lift-off of film cooling accumulations from the D9 test surface as BRf becomes larger and greater amounts of coolant are ejected from the film cooling holes. Magnitudes of correlation equation coefficients additionally indicate the presence of local boundary layer structural changes along the pressure side rim with the D9 arrangement. Different behavior is characterized by correlation coefficients for the D9 suction side rim. Here, increased magnitudes of heat transfer coefficient ratios with BRf evidence increased thermal transport and mixing as greater amounts of coolant are ejected from the film holes. Such suction side and pressure side rim variations are a consequence of a diversity of complex, interacting film coolant phenomena.

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