SE355635

1,247,144. Gas turbine engine combustion chambers. UNITED AIRCRAFT CORP. March 5, 1970 [April 2, 1969], No.10595/70. Heading F1L. The invention relates to combustion equipment of a gas turbine engine and in particular to a flame tube thereof, the flame tube being of double-wall construction and formed to provide longitudinallyextending cooling air passageways therein. Air inlet ducts extend through the wall of the flame tube for inflow of dilution air into the interior of the flame tube, the ducts extending across the cooling air passageways, each duct being provided with means for conducting cooling air flowing in passageways upstream of the duct to passageways downstream of the duct. The flame tube comprises sections 50, 56 each comprising an inner wall 40 and an outer wall 42 the inner wall being formed with longitudinally extending fins 62 which co-operate with the outer wall 42 to form longitudinally-extending cooling air passageways 60. The flame tube sections 50, 56 are of increasing diameter in the downstream direction, adjacent sections overlapping as at 54. Air inlet openings are formed through the flame tube walls and ducts 28 Fig. 3 are inserted through the openings, the ducts being of toroidal form defining an annulus 78 as shown whereby cooling air flowing in the passageways 60 upstream of the inlet duct may pass to the passageways 60 downstream of the inlet duct. In Fig. 2 (not shown) the duct 28 is of cylindrical form and the toroidal annulus (98) is formed by a ring member (94) secured to the duct.