| 摘要 |
A lean, low NOx gas-fired can combustor having liquid fuel operation capability includes a housing, a combustor liner disposed within the housing and defining a combustion zone for combusting fuel with air, and a head assembly for joining the longitudinal housing and liner ends and for supporting swirler vanes that admit about 45-55% of a total combustor air flow to the combustion zone. The head assembly includes multiple gaseous fuel injection ports upstream of the swirler vanes, and a single liquid fuel injector positioned along the liner axis for directing atomized liquid fuel into the combustion zone. The head assembly further includes a heat shield disposed between the injector and the combustion zone, and the head assembly is configured to provide a flow of air for cooling the heat shield during all operations of the can combustor. The can combustor may also include apparatus for automatically purging the liquid fuel injector with compressed air, such as cooled compressed air from a gas turbine engine compressor stage. The apparatus includes a shuttle valve controller including a shuttle member biased by a first pressure towards a first position interconnecting the liquid fuel input to the liquid fuel injector inlet, while blocking compressed purging air flow, and biased by a second pressure towards a second position interconnecting the compressed purging air input to the liquid fuel injector inlet, while blocking liquid fuel flow.
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