Gas Turbine Combustion Chamber Types

COMBUSTION SECTION Combustion Chamber Types Multiple Can ~ This type of combustion chamber chamber is used on centrifugal compressor compressor engines and the earlier types of axial flow compressor compresso r engines. It is a direct development of the early type of Whittle combustion chamber. ~ Each chamber has an inner flame tube around which there is an air casing. ~ The separate The  separate flame tubes are all interconnected  which  which allows each tube to operate at the same pressure and tubes during engine starting. also allows also allows combustion to propagate around the flame tubes during CanCan-annular -annular (Cannular) (( Cannular)   ~ The tubo-annular combustion chamber is a combination of the multiple and annular types. ~ A number of flame tubes are fitted inside a common air casing. ~ The airflow is similar to that already described and this arrangement embodies the ease of overhaul and testing of the multiple system with the compactness of the annular system. system.  Annular ~ This type of combustion chamber consists of a single flame tube, completel c ompletelyy annular in form,  which is contained in an inner and outer casing. ~ The airflow through the flame tube is similar to that previously described, the chamber being open at the front to the compressor and at the rear to the turbine nozzles. ~ The main advantage of the annular chamber is that,  for the same power output, the length of the chamber is only only  75 per cent of that of a tubo-annular system  system  for an engine of the same diameter,  resulting in considerable  saving of weight and production cost . ~ Another advantage is that because interconnectors are not required, the propagation the  propagation of combustion is improved. Reverse flow annular (see below) ~ The air flows over the liner and enters from the rear. ~ Combustion gas flow is in the opposite direction to normal flow through the engine. ~ Reverse flow combustion chambers are used where the engine length is critical  or  or where the thrust of the engine is  not being produced by the exhaust of the primary air. ~ They are often found on APU’s, turboprop and turbo-shaft engines.