Gas Turbine Handbook : Principles and Practices

Hardware 37
combustor and the annular (including the single combustor) combustor
sections. There are generally two types of can-annular combustors:
one is the more efficient straight flow-through; the other is the reverse
flow combustor (Figure 3-12). The advantage of the reverse flow combustor,
as used in the heavy industrial gas turbine, is that this design
facilitates the use of a regenerator, which improves overall thermal efficiency.
A further distinctive design approach within the can-annular
concept is a single fuel nozzle and multi-fuel nozzles per combustion
chamber. In theory, a large number of fuel nozzles provide better dis-
Figure 3-12. Courtesy of United Technologies Corporation, Pratt &
Whitney Aircraft. A combustor outlet view of one of the nine combustors
in the, 25.5 megawatt, FT8 aero-derivative gas turbine. Flame
temperature at the center of the combustor approaches 3,000°F. The
small cooling holes enable a flow of compressor air to continuously
cool the combustor liner walls.