Patent GB-902510-A (GB)
Title: Improvements in or relating to combustion chambers
Inventor: BARNWELL STEPHEN DOWNING
IPC: F23R3/32
Filed: 1960-04-19
Abstract: 902,510. Generating combustion products under pressure. BRISTOL SIDDELEY ENGINES Ltd. April 4, 1961 [April 19, 1960 (2); Dec. 9, 1960], Nos. 13595/60, 13596/60 and 42383/60. Class 51 (1). A combustion chamber for a gas turbine engine comprises an outer casing and at least one flame tube disposed therein, the flame tube having at or adjacent its upstream end a plurality of fuel vaporizer pipes each having an outlet arranged to discharge a mixture of fuel and primary air into a combustion region within the flame tube. In accordance with the invention, the upstream end of the or each flame tube defines a trough which is disposed within a diffusing inlet to the outer casing, the trough being open to the interior of the flame tube and opening in a downstream direction, a plurality of vaporizer pipes being located within the flame tube adjacent the upstream end thereof and each having a primary air inlet open to the interior of the outer casing, fuel inlet means, and an outlet so disposed as to discharge the mixture of vaporized fuel and primary air in an upstream direction into the trough. A plurality of air supply pipes is mounted on the wall of the flame tube and extending into the flame tube, each air supply pipe having at least one opening, disposed downstream of the combustion region and through which in operation, air is introduced in a lateral direction into the flame tube. The combustion equipment shown in Figs. 1 and 2 comprises an annular outer casing 1, 2 within which is disposed an annular flame tube 4, the upstream end of which is shaped to form a trough 7 facing downstream, the trough being located within the diffuser portion 3 of the outer casing. A series of L-shaped fuel vaporizer, pipes 8 extends into the flame tube through the outer wall thereof, the shorter limb of each pipe being directed upstream into the trough 7. Each pipe has an air inlet portion 9 extending into the space between the outer walls of the casing and flame tube, also a fuel inlet pipe 10. The outlet ends of the pipes may be inclined so as to impart a circumferential component to the fuel and air discharging therefrom. A series of air inlet pipes 12 extends from openings in the upstream end of the flame tube, each pipe having a pair of outlets 14 facing radially inwardly and outwardly. The outer wall of the flame tube is formed with air inlet openings 15 which are disposed opposite the radially outwardly openings 14 of the air inlet pipes 12. The flame tube is also formed with further air inlets 16, 17. In a second embodiment, Figs. 4 and 5, the upstream end of the flame tube 28, 29 which is again of annular form, is shaped to provide two annular troughs 31 facing downstream, also an annular trough 33 facing upstream. Fuel vaporizer pipes 32 of J-shape extend from openings in the trough portion 33, the outlet limbs of the J-pipes being directed upstream towards the annular troughs 31, one pipe discharging into, say, the outer trough and the next discharging into the inner trough. Air inlet pipes 40 are disposed between each pair of fuel vaporizer pipes, each pipe 40 having radially inwardly and outwardly directed outlets 41 as in the first embodiment. The inner and outer walls of the flame tube have radially directed air inlet openings 43 disposed opposite the outlets 41. The flame tube is formed with further air inlets 35. A pair of ring members 25, 26 is disposed within the air diffusion passage 23 upstream of the flame tube, the rings acting to divide the air stream as described in Specification 902,511.