Date of Award

January 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Forrest E. Ames

Abstract

Gas turbines play a very critical role in the current energy sector in both power generation and in propulsion for almost the entire commercial and military aviation industry. Higher efficiencies can be developed from gas turbines, either land based or aero-propulsion by raising both the pressure and the temperature of combustion gases which discharge into the turbine section, which is also known as the Turbine Entry Temperature (TET). Turbine blade materials simply cannot operate safely at current TET’s of 3000 °F without implementing comprehensive cooling schemes developed in the industry over the years. Normally some of the compressed air is extracted from the compressor discharge and forced into internal cooling passages including serpentine passages in blades to cool the hottest engine components to a safer range in metal temperatures. Often, a portion of air is forced out from an array of tiny holes concentrated in the leading edge of blade aimed to provide internal cooling and a thin layer of protection from hot combustion gases while the rest of the coolant is delivered internally for convection to cool component surfaces to a sustainable temperature. However, the leading edge is quite susceptible to deposition of contaminants from the combustion products which can buildup and plug film cooling discharge holes. In addition, the surface of the leading region experiences intense turbulence, and the turbulence disrupts the film cooling layer from forming stably and protecting the blade surfaces.

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