with each other so as to introduce an effect whereby the streams of fuel air mixture emerging from the two passages 127 128 wrap around each other such interlocked passages i e passages with alternating geometries could be machined easily with shaped cutters the curvatures of the first and second air passages 127 128 respectively correspond to the curvatures of the air passages 17 in the first embodiment a third embodiment of the inventive combustor is partly shown in fig4 a and 4 b while fig4 a shows the burner 203 the swirler 211 and a part of the pre chamber 205 of the third embodiment in a longitudinal section fig4 b shows the swirler 211 of the third embodiment in radial section further shown in fig4 a and 4 b is a cooling channel 250 which is formed between an inner chamber wall 252 and an outer chamber wall 254 of the pre chamber 205 through the cooling channel 250 cooling air flows in order to cool the inner wall 252 of the pre chamber 205 the swirler 211 is in flow connection with the cooling channel 250 so that cooling air enters the swirler 211 after streaming through the cooling channel 250 the cooling channel could also be present between an outer and inner wall of a dome portion similar to the dome portion 15 in fig1 in this case the pre chamber and the main chamber would merge to one volume in the present embodiment the swirler 211 includes six.