Mitch Busche

Date of Award

January 2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Forrest E. Ames

Abstract

Modern turbine designers are greatly concerned with power out and the efficiency of their engines. One way to increase the power output and effectiveness of the engine is to increase the hot gas temperature inside the combustion chamber. The hot gas can reach a temperature that exceeds the physical limitations of parts inside the engine, causing the parts to fail prematurely. One possible method to cool the parts is with the use film cooling. Film cooling takes cool air from the compressor, bypasses the combustor, and ducts the air to internal chambers of parts, and then ejects the cool air onto the surface of the part. This provides both cooling and protection from deposition.

Due to the large number of turbine engines in service today, it is impossible to know what the perfect film cooling package is. Different turbines have different inlet conditions, burn at different temperatures, have different turbulence intensities in the flow, and require different amount of cooling. Research has been done in the past to determine some of the parameters that affect film cooling performance. The purpose of this research was to determine the effects of turbulence, Reynolds number, and blowing ratio on the adiabatic effectiveness of film cooling and the downstream heat transfer. This research utilized the large scale, low speed cascade wind tunnel facility at the University of North Dakota. The effectiveness of two different cylindrical leading edge test surfaces was investigated.

For this project, a unique pin fin array was developed and integrated in the two cylindrical leading edge test sections. The test sections were designed, fabricated, and instrumented to be able to acquire temperature measurements and pressure measurements at different locations along the test surface. A way to produce and deliver coolant air was designed, fabricated, and instrumented. Data was acquired for each of the cylinders at the different test conditions. The turbulence intensities were acquired by another student.

In the future, additional data will be taken with the cylindrical test sections. Temperature data while film cooling will be measured via infrared camera. Shaped coolant ejection holes are being designed and will be tested. A leading edge with deposition will also be tested. All of the future data will be compared to this baseline data. Hopefully, the data from this research will be used by turbine designers to better understand the effects on film cooling, and produce a better, more efficient engine.

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