Page 182 - The Jet Engine

8. An atomized fuel spray is fed into the jet pipe 16-3): this latter method is known as 'hot-shot'
through a number of burners, which are so arranged ignition. Once combustion is initiated, the gas
as to distribute the fuel evenly over the flame area. temperature increases and the expanding gases
Combustion is then initiated by a catalytic igniter, accelerate through the enlarged area propelling
which creates a flame as a result of the chemical nozzle to provide the additional thrust.
reaction of the fuel/air mixture being sprayed on to a 9. In view of the high temperature of the gases
platinum-based element, by an igniter plug adjacent entering the jet pipe from the turbine, it might be
to the burner, or by a hot streak of flame that assumed that the mixture would ignite spontaneous-
originates in the engine combustion chamber (fig. ly. This is not so, for although cool flames form at

Fig. 16-3 Methods of afterburning ignition.

172