called primary air and that for cooling is secondary air. The
secondary air is controlled and directed by holes and louvers in the
Igniter plugs function only during starting, being cut out of
the circuit as soon as combustion is selfsupporting. On engine
shutdown, or, if the engine fails to start, the combustion chamber
drain valve, a pressureactuated valve, automatically drains any
remaining unburned fuel from the combustion chamber. All combustion
chambers contain the same basic elements: a casing or outer shell, a
perforated inner liner or flame tube, fuel nozzles, and some means of
initial ignition. The combustion chamber must be of light
construction and is designed to burn fuel completely in a high
velocity airstream. The combustion chamber liner is an extremely
critical engine part because of the high temperatures of the flame.
The liner is usually constructed of welded highnickel steel. The
most severe operating periods in combustion chambers are encountered
in the engine idling and maximum rpm ranges. Sustained operation
under these conditions must be avoided to prevent combustion chamber
liner failure.
a. The annulartype combustion chamber shown in figure 1.18
is used in engines of the axialcentrifugalflow compressor de
1. ANNULAR TYPE COMBUSTION CHAMBER LINER
2. COMBUSTION CHAMBER HOUSING ASSEMBLY
Figure 1.18. Annulartype Combustion Chamber.
36
Previous Page
