Award Date

5-1-2012

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

Yitung Chen

Second Committee Member

Robert Boehm

Third Committee Member

Hui Zhao

Fourth Committee Member

Yahia Baghzouz

Number of Pages

124

Abstract

The goal for this thesis is to minimize clearances and tolerances, in order to prevent water leakage. A proper seal on the seal rings does not let excess water flow through the turbine runner, thus conserving more water and wasting less energy. Moreover, water leakage past worn wear plates allows for an extra load for the turbine when operating in condense mode. When the wicket gates are closed, water leakage past worn plates wastes mechanical energy in the water; thus, decreasing the efficiency of the Francis turbine, especially when operating at partial loads. Furthermore, the wicket gates also known as guide vanes can increase the efficiency of the turbine in their relation to their laminar profile and proper seal.

Water is a very vital resource in today's society. This thesis illustrates how existing hydro machinery can be improved to reduce the dependency on fossil fuels as an electric energy source. This study provides actual examples of improvements using the generating units located at Hoover Dam. Hoover Dam located in Boulder City, NV is part of the Lower Colorado Region, of the U.S. Department of the Interior Bureau of Reclamation.

Overhauling a hydro unit to obtain better efficiency is very similar to overhauling a vehicles engine to improve the vehicles fuel economy. Modifying and replacing three major hydro-machinery components: seal rings, wear plates, and wicket gates, improves the efficiency of Hoover Dam units by an average of 2 percent. This increase in capacity equates to an additional 8,000 MW-hrs per year per unit. The wholesale market value of this increase in energy and capacity, roughly equates to about $290,000 per unit per year [1]. Engineering design, calculations, and performance test were conducted to improve the parameters of the seal rings, wear plates, and wicket gates. MATLAB"®" and MS Excel computer software was used to analyze testing results and provide data and calculation results.

This study focuses mainly on the seal rings, wear plates, and wicket gates. In order to achieve a 2% efficiency gain and about a 3% to 5% capacity gain per unit, the dimensions of the wear plates and seal rings were changed to have tighter clearances, and the wicket gate design and profile were changed by increasing the angle of attack by 2 degrees, and by increasing the trailing edge gap by 0.02 inches. Additionally, the servo motors were stroke 2.5 feet more to achieve the 2 percent increase in efficiency.

As water levels keep on dropping in the Colorado River, future research and analysis can be allocated in a new turbine runner design for low head operation ranges. Additionally, there are a few other mechanical and electrical components that can be modified or alternated to monitor and improve capacity efficiency.

Keywords

Efficiency and capacity; Hydroelectric generators; Hydroelectric power plants – Equipment and supplies; Mechanical efficiency; United States – Hoover Dam

Disciplines

Engineering | Mechanical Engineering | Oil, Gas, and Energy

Language

English


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