Chemiluminescence and high speed imaging of reacting film cooling layers

Date of Award

2011

Degree Name

M.S. in Aerospace Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Dilip Ballal

Abstract

The demand for more efficient and compact gas turbine engines has resulted in an increase in the operating temperatures and pressures and a decrease in combustor weight and size. These advances may result in incomplete combustion products entering the turbine section. The products can react with the air intended to cool the turbine vanes, and the resulting flame can cause damage to the engine. This study reports chemiluminescence measurements of flames and correlates these to heat release rate and the measured heat flux to a surface. To accomplish this, fuel rich combustion products are generated in a well-stirred reactor. The flow of products is directed over a flat plate with cooling air jets normal to the flow. Chemiluminescence data of the flames is obtained, along with high speed images, and temperature measurements of the flow inside the test section. Three film cooling geometries are studied: normal holes, fan shaped holes, and slot. Measurements are acquired at three equivalence ratios (1.3, 1.4, and 1.5) at three different blowing ratios (M = 1, 4, and 7). It is found that the rate of heat release from the flame does not always trend the same as the heat transfer to the surface. It is also seen that a large reaction region does not always equate to high heat flux to the surface. If enough cooling air is present the surface is protected from the heat released from the flame.

Keywords

Chemiluminescence Diagnostic use, Thin films Cooling, Aircraft gas-turbines Cooling, Aircraft gas-turbines Combustion, Heat Transmission Measurement

Rights Statement

Copyright © 2011, author

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