COMBUSTION STAGING SYSTEM

摘要

A combustion staging system for fuel injectors of a multi-stage combustor of a gas turbine engine is provided. The system has pilot and mains fuel manifolds respectively distributing fuel to pilot and mains stages of the injectors. The system further has a splitting unit which controllably splits a metered fuel flow and sends respective portions of the metered flow to the pilot and mains fuel manifolds to perform staging control of the combustor. The splitting unit is able to deselect the mains manifold so that there is no flow into the combustor from the mains manifold. The system further has a cooling flow recirculation line having a delivery section arranged to provide a cooling flow of fuel to the mains manifold when that manifold is deselected so that the deselected mains manifold remains primed with relatively cool fuel. The recirculation line further has a return section arranged to collect the cooling flow from the mains manifold. The system further has one or more fuel pressure sensors which detect the pressure of the cooling flow on the recirculation line. The system further has a control arrangement which is adapted to close off the recirculation line when the pressure sensor(s) indicates a failure of the cooling flow.