Abstract: Combustion system for gas turbines and the like, comprising an outer shell connected to a source of pressurized air and surrounding a flame tube which comprises a combustion chamber and a mixing chamber defined within a double wall construction comprising an outer wall and an inner wall forming an annular cooling jacket axially surrounding the mixing chamber. A portion of the pressurized air is directed radially into the mixing chamber through a plurality of nozzles which are spaced about the cooling jacket, while another portion of the air is passed into said annular jacket through apertures in the outer wall alternating with and spaced a distance from said nozzles to produce a plurality of diverging high velocity peripheral streams which sweep and cool the walls of the jacket preliminary to being passed into the mixing chamber through apertures in the inner wall which are aligned with said nozzles.