GB909580A - Improvements in combustion chamber assemblies - Google Patents

Abstract

909,580. Generating combustion products under pressure. GENERAL ELECTRIC CO. Oct. 28, 1959, No. 36557/59. Class 51 (1). In a combustion chamber assembly comprising a louvred flame tube having a louvred end dome and a cowl forming with the dome a dome cooling chamber, a series of circumferentially spaced openings are formed in a cylindrical portion of the cowl and the series of intervening elements so formed are secured to a cylindrical portion of the dome. In addition, a series of circumferentially spaced offset areas on the upstream end of the flame tube are secured to the cylindrical portion of the dome between the cowl elements so that the dome, cowl, and flame tube are nowhere joined by more than two thicknesses of material. The openings may be situated along the edge of the cylindrical portion of the cowl so that the intervening elements are formed as fingers. The offset areas of the flame tube provide axial channels for the flow of coolant over the inner surface of the flame tube. As shown an annular combustion chamber assembly 11 for gas turbine engines comprises a flame tube having inner and outer shells 14, 12 defining a combustion chamber 22, a dome 16 and a cowl 18. The outer shell 12 has an upstream end portion with the offset areas 73 extending radially inwardly and defining axially extending channels 74 which portion overlaps fingers 70 extending from a cylindrical portion 58 of the cowl 18. The fingers 70 are welded to a cylindrical portion 54 of the dome 16, between the offset areas 73. In forming the offset areas 73 louvre openings 82 extending radially inwardly from the shell 12 are produced. The offset areas 73 are separated by parts 84 of the shell 12 and louvre openings 88 are formed between the parts 84 and the fingers 70. The thickness of the stock of which the cowl, and flame tube are made is less than the radial depth of the offset parts so that the louvre openings 82, 88 and therefore the film of cooling air extend almost completely round the flame tube. The radially inner limbs 52, 64 of the dome 16 and cowl 18 respectively are similarly joined to the radially outer surface of the inner shell 14. Apertures 45 in the cowl 18 and apertures 46 in the dome 16 are formed to receive fuel nozzles. The area of each aperture 45 is greater than that of its fuel nozzle permitting a flow of air from a plenum chamber 6 into the dome cooling chamber 42. Louvres 90 and 92 are formed circumferentially in dome 16 to permit the flow of cooling air from the chamber 42 along the cylindrical portions 54, 60 of the dome 16.