Gas turbine combustion chamber

A gas turbine combustion chamber 10 has a combustion chamber housing 11 and a burner 12, with at least a portion of the burner positioned in the combustion chamber housing. A flame tube 15 is also positioned in the combustion chamber housing, and the flame tube provides a primary combustion zone 16 of the gas turbine combustion chamber. A flame tube cover 17 is positioned on an upstream end of the flame tube and an adjacent mixing tube 19 extends radially and adjoins the flame tube cover. An axial air flow passage 20 is formed between the mixing tube and the flame tube cover, and in use, the axial air flow passage conducts cooling air in an axial direction outside and along the mixing tube. Radial air flow ducts 22 are provided in the flame tube cover and conduct the air following the axial air flow passage to cool the flame tube cover. The radial air flow ducts in the flame tube cover may follow a curved or spiral pathway (22 Fig 2), and a seal 28 may be provided between the mixing tube and flame tube cover. The improved cooling increases the lifespan of the combustion chamber.