Page 51 - The Jet Engine

Combustion chambers

Fig. 4-8 Tubo-annular combustion chamber.

also greatly improves the preparation of fuel for 24. The gas turbine engine operates on a constant
combustion by aerating the over-rich pockets of fuel pressure cycle, therefore any loss of pressure during
vapours close to the spray nozzle; this results in a the process of combustion must be kept to a
large reduction in initial carbon formation. minimum. In providing adequate turbulence and
mixing, a total pressure loss varying from about 3 to
COMBUSTION CHAMBER PERFORMANCE
8 per cent of the air pressure at entry to the chamber
23. A combustion chamber must be capable of is incurred.
allowing fuel to burn efficiently over a wide range of
operating conditions without incurring a large Combustion intensity
pressure loss. In addition, if flame extinction occurs, 25. The heat released by a combustion chamber or
then it must be possible to relight. In performing any other heat generating unit is dependent on the
these functions, the flame tube and spray nozzle volume of the combustion area. Thus, to obtain the
atomizer components must be mechanically reliable. required high power output, a comparatively small

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