Gas Turbines A Handbook of Land, Sea and Air Applications

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Fig. 1. Rolls Royce RB211 Dry Low Emissions Gas Generator
(Source: Process Plant Machinery, 2nd edition, Bloch & Soares, C.
pub: Butterworth Heinemann, 1998)
* Condensed extracts from selected chapters of “Gas Turbines: A Handbook of Land, Sea and Air Applications” by
Claire Soares, publisher Butterworth Heinemann, BH, (for release information see www.bh.com) Other references
include Claire Soares’ other books for BH and McGraw Hill (see www.books.mcgraw-hill.com) and course notes
from her courses on gas turbine systems. For any use of this material that involves profit or commercial use
(including work by nonprofit organizations), prior written release will be required from the writer and
publisher in question.
Please note that several topics in the gas turbine handbook, for instance Turbine Controls, Instrumentation and
Diagnostics; as well as Performance Optimization and Environmental issues are not covered in this author’s material
on this CD. The “Gas Turbines” book in question is several hundred pages long and besides the basics, covers some of
the more complex and lengthy work in recent gas turbine development. Condensing it all here was not practical. What
is here however, does give the reader the basic theory and practice of gas turbines in simple cycle and combined cycle
mode, in power generation service.
1
GAS TURBINES IN SIMPLE CYCLE & COMBINED
CYCLE APPLICATIONS*
Gas Turbines in Simple Cycle Mode
Introduction
The gas turbine is the most versatile item of turbomachinery today. It can be used in several
different modes in critical industries such as power generation, oil and gas, process plants,
aviation, as well domestic and smaller related industries.
A gas turbine essentially brings together air that it compresses in its compressor module, and
fuel, that are then ignited. Resulting gases are expanded through a turbine. That turbine’s shaft
continues to rotate and drive the compressor which is on the same shaft, and operation
continues. A separate starter unit is used to provide the first rotor motion, until the turbine’s
rotation is up to design speed and can keep the entire unit running.
The compressor module, combustor module and turbine module connected by one or more
shafts are collectively called the gas generator. The figures below (Figures 1 and 2) illustrate a
typical gas generator in cutaway and schematic format.