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Gas Turbine Systems Supervisor - Supervisor manual for Gas Turbine Engines | Next
Figure 2-21.—Combustion liner dome igniter tube. |
Figure 2-19.—Combustion liner dome band and plate cracks.
Cracking (fig. 2-19) in the dome band area occurs
at relatively low operating time. Record the number of
cracks and their relationship to one another. Indicate if
these cracks are parallel, T-shaped, circumferential or
angled to connect and separate part of the band, and so
forth.
All the missing metal areas or burn-throughs (fig.
2-20) must be recorded. For the dome bands, estimate
the magnitude by the number or partial/circumferential
span of the dimples and axially by percent of span of the
band overhang to the trumpet. Record the trumpet areas
of burn-away and burn-through of the dome plate
around the swirl cups. Burn-through in the combustor
dome will reduce cooling flow to the HP turbine vanes.
Monitor the HP turbine vane condition as burn-through
progresses.
Igniter Tubes and Ferrules.— Inspect the two
igniter locations (fig. 2-21) for the condition of the weld
at the cutaway of the trumpet and the dome band. The
ferrules are visible from these ports. Record the
condition for evidence of cracking, 10SS of ferrule metal,
or both. Cracking from the igniter tube aft to the panel
overhang is common.
Figure 2-20.—Combustion liner dome bums and missing
metal.
2-16
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