GB1346600A - Flame tubes for gas turbine engines - Google Patents

Abstract

1346600 Gas turbine combustion chambers JOSEPH LUCAS (INDUSTRIES) Ltd 2 Aug 1971 [12 June 1970] 28539/70 Heading F1L A flame tube for a gas turbine engine comprises a first tube member 45, Fig. 4, of ceramic material secured to a second tube member in axially-spaced concentric relationship by clamping, means which compensates for differential thermal expansion between the clamping means and at least one of the tube members. The clamping means has frusto-conical surfaces on metal members 51, 52 and 54, 55 which co-operate with complementary surfaces on ceramic tube members 45, 46, the included angle of the surfaces being such that substantially constant clamping force is maintained at the co-operating surfaces during differential thermal expansion. A ceramic air baffle 57 is similarly secured by clamping means 58, and is located in the inlet end of the flame tube by a system of relatively slidable rods 60 and tubes 59. The flame tube is attached by lugs 66 to a structure 62 defining with a cylinder 70 of expanded metal mesh, an annular space 63 through which air is introduced. The air flows into the flame tube through the annular gap at the periphery of baffle 57, the axial gap between the tube members 45, 46, and dilution holes 56. In Fig. 3 (not shown), the upstream tube member is composed of several axially-stacked frusto-conical ceramic rings (32) clamped together by differential thermal expansion compensating clamping means which also couples the two tube members together in axially-spaced relationship. In Fig.1, each tube member 10, 11 comprises four quadrants 14 and and 19 respectively, each quadrant having radial lugs (15), Fig.2 (not shown) at their circumferential ends by which they are secured together by clamping means 16 and 20. The latter have clamping elements 16a, 16b and 20a, 20b for this purpose, the co-operating surfaces of these elements and the lugs (15) being tapered radially inwardly to compensate for differential thermal expansions. Packing material may be located between the co-operating clamping surfaces in all arrangements described.