CPC F02C 9/50 (2013.01) [F02C 9/16 (2013.01); F23C 7/008 (2013.01); F23R 3/26 (2013.01); F23R 3/343 (2013.01); F05D 2270/082 (2013.01)] | 19 Claims |
1. A gas turbine engine comprising:
a variable geometry combustor having pilot fuel injectors and main fuel injectors;
a fuel meter configured to control fuel flow to the pilot fuel injectors and the main fuel injectors;
a variable geometry airflow arrangement for the variable geometry combustor, which is configured to vary the airflow through the pilot fuel injectors and/or the main fuel injectors; and
a control system configured to control the variable geometry airflow arrangement in dependence upon airflow delivered to the combustor, the fuel flow to the pilot fuel injectors and the main fuel injectors, and a target index of soot emissions, thereby controlling airflow through the pilot fuel injectors and/or the main fuel injectors and hence the quantity of soot produced by combustion,
wherein the control system is configured to respond to a decrease in the target index of soot emissions by controlling the variable geometry airflow arrangement to decrease the airflow through the main fuel injectors relative to the airflow through the pilot fuel injectors.
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