Method for the adaption of the operation of a staged combustion chamber for gas turbines

Abstract

This invention relates to a fuel injection system for a staged combustion chamber () of a gas turbine aero-engine, in which a certain quantity of fuel is permanently supplied to the pilot burner(s) () and in which fuel is apportioned to the main burner(s) () only at higher engine performance, whereby a staging valve unit () which variably splits the total fuel mass flow (WF) to the pilot burners () and to the main burners () is provided downstream of a control valve unit () which controls the entire fuel mass flow, with both valve units being actuated by an engine control unit () and with the actuation of the staging valve unit () being accomplished on the basis of the desired engine performance, characterized in that the engine performance is described by way of a staging parameter (SP) reflecting the load of the gas turbine combustion chamber () and actuating the staging control unit () according to a switching line, in that the staging parameter (SP) is derived from a functional relationship, in that a downstream summation point is provided for the computation of the difference between an actual value of the staging point and a value of the nominal staging point, and in that a time element (TIMER) is provided subsequent to the summation point, said time element being designed such that switch-over is delayed upon overshooting or undershooting of the adjusted staging point, respectively, if the period since the execution of the previous staging event is smaller than a pre-defined time constant held in a family of characteristics.