stream area 18 is thus embodied in the manner of a diffuser this has the effect that the fuel exhaust air mixture in the flow direction slows down as a result of which its dwell time in the combustion chamber 8 increases the exhaust air l and the fuel b can therefore mix well so that a special combustion with a low static temperature takes place in which a reduced quantity of nitrogen oxide is produced the dwell time of the gases in the combustion chamber 8 can essentially be adjusted by two parameters this can take place on the one hand by way of the speed to which the gases l b in the diffuser are decelerated this speed is a function of the angle of inclination of the outer wall 32 u2032 and the length of the stream area 18 the dwell time can on the other hand also be influenced by the length of the mixing region 20 if such a mixing region 20 is specified mounting the second turbine 6 in a radially higher position in respect of the first turbine 4 takes place in a second step in the region of the combustion region 22 which is embodied in the manner of a nozzle here the outer wall 32 u2032 of the combustion chamber 8 remains at the highest radial.