Experimentally determined external heat transfer coefficient of a turbine airfoil design at varying incidence angles
Packard, Gavin Ray
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Predicting and measuring external heat transfer coefficients of hot gas path turbine components are important tools for gas turbine designers. Inlet temperatures often exceed the melting temperature of the materials used in such components, requiring protective measures such as thermal barrier coatings or film-cooling to prevent component failure. The external heat transfer coefficients can be used to design for the thermal loading that will ultimately lead to such failures. Modern engine designers use computational codes to predict the conditions of the hot gas components during engine operation. Before these codes can be relied upon as accurate, they must first be verified with experimental measurements. However, measuring the heat transfer coefficients can be a difficult process, especially on an actual engine component, due to the extreme temperatures and inaccessibility. As such, low speed, low temperature wind tunnels are often used to simulate a scaled version of turbine components to collect experimental data to assist in validating computational codes. This thesis details the construction of scaled up turbine airfoils to collect such data. It also provides data covering the generation of turbulence using an array of vertical rods upstream of a linear cascade in a low speed wind tunnel at off-normal incidence flow angles.