length, decreasing from the first to the third stage. The No. 1 bearing is a ball bearing and supports the
rear of the compressor assembly in the inlet case. The No. 2 bearing is a roller bearing and supports the
front of the compressor and gas generator turbine.
c.
The gas generator case is attached to the front flange of the compressor inlet case and
consists of two stainless steel sections made into a single structure. The rear inner section supports the
compressor assembly. The compressor bleed valve outlet port is located at the seven o'clock position
forward of the inlet screen. The No. 2 bearing support is located in the centerbore of the case. The
diffuser pipes or vanes brazed inside the center section of the gas generator case create a pressure
increase in the compressor air as it leaves the centrifugal impeller. The compressed air is then directed
through straightening vanes, located at the outlet of the diffuser, and out to the combustion chamber
liner.
The front section of the gas generator case forms the outer housing for the combustion
chamber liner. It consists of a circular stainless steel structure for mounting the 14 fuel nozzle
assemblies and the manifold. Front and rear drain valves are mounted at the 6 o'clock position to allow
residual fuel to drain overboard during engine shutdown after a false or aborted start. Two glow plugs
protrude into the combustion chamber liner to ignite the fuel-air mixture. The engine is mounted on
three flexible type mounts which are secured to mounting pads located on the outer circumference of
the gas generator case.
9.6.
COMBUSTION CHAMBER LINER
Located in the front section of the gas generator case is the combustion chamber liner. The
liner is of the reverse flow type and consists primarily of an annular, heat-resistant steel liner open at one
end. The combustion chamber is illustrated in figure 9.7.
The liner has perforations which allow air to enter the liner for combustion. The
perforations insure an even temperature distribution at the compressor turbine inlet. The domed front
end of the liner is supported inside the gas generator case by seven of the 14 fuel nozzles. The rear of
the liner is supported by sliding joints which fit to the inner and outer exit duct assemblies.
232
Previous Page
