Patent EA-002319-B1 (EA)
Title: A gas turbine engine combustion system
Inventor: MAINA THEODORY ISHAK
IPC: F23R3/48
Filed: 1999-07-12
Abstract: 1. A gas-turbine engine combustion system in which adjacent combustors are connected by a crossfire tube assembly adapted to pass an ignition flame (110) from an ignited combustor to another combustor. wherein each crossfire tube assembly comprises inlet means (105) for introducing air (106) to film-cool an inner ignition flame-facing surface of the crossfire tube assembly, characterised by cooling means (107; surrounding the crossfire tube assembly at its connection to a combustor (100) and adapted to film-cool an outer surface of the crossfire tube assembly, thereby creating film cooling over both inner and outer surfaces of the crossfire tube assembly. 2. A gas turbine engine combustion system comprising a plurality of combustors, a crossfire tube assembly for passing an ignition flame (110) between adjacent combustors, each crossfire tube assembly including an end-tube (104) for passing the ignition flame into and out of a combustor (100), the end-tube having an inner surface and an outer surface, and means (103,105) for feeding coolant air (106) into the crossfire tube assembly so as to film-cool the inner surface of the end-tube (104), characterised in that the end-tube (104) is connected to the combustor (100) through a sleeve (107) which extends from a wall (101) of the combustor to surround and overlap the end-tube over a part of its length adjacent the combustor, thereby to define an annular gap (G) between the outer surface of the end-tube and an inner surface of the sleeve, the sleeve having inlet means (108) for introducing coolant air (109) into the annular gap so as to film-cool both the outer surface of the end-tube (104) adjacent the combustor wall (101) and the inner surface of the sleeve (107). 3. A gas-turbine engine combustion system according to claim 2, in which the sleeve (107) is provided with a plurality of apertures (108) therearound, adjacent to a point at which the sleeve is connected to the end-tube (104), so that air (109) is admitted to film-cool the outer surface of the end-tube. 4. A gas-turbine engine combustion system according to claim 2 or claim 3, in which the end-tube (104) is arranged so that it does not extend beyond the sleeve (107) into the interior of the combustor (100). 5. A gas-turbine engine combustion system according to claim 2, in which the overlap between the sleeve and the end-tube does not extend over the entire lengthwise extent of the sleeve, whereby there is a gap (D) between an internal surface of the combustor wall (101) and the end-tube (104). 6. A gas-turbine engine combustion system according to claim 5, in which the gap (D) as measured between the end-tube (104) and an inner surface of the combustor wall (101) is approximately twice the annular gap (G) between the inner surface of the sleeve and the outer surface of this end-tube. 7. A gas-turbine engine combustion system according to any one of claims 2 to 6, in which the sleeve (107) is arranged such that cooling air exits from the sleeve over an inner surface of the combustor wall (101) surrounding sleeve. 8. A gas-turbine engine combustion system according to any preceding claim, in which a complete crossfire tube arrangement extending between first and second combustors comprises a central crossfire tube portion (102) and first and second end-tubes (104) extending from the first and second combustors respectively, a first end of the central crossfire tube portion being welded into the first end-tube and a second end of this central crossfire tube portion being a push-fit into the second end-tube, cooling air (106) being directed into an annular gap formed between an outer surface of the central crossfire tube portion (104) and an inner surface of each end-tube (104) to film-cool the ends of the central crossfire tube portion and the inner surfaces of the end-tubes. 9. A gas-turbine engine having a combustion system according to any preceding claim.