GB1273017A - Improvements in or relating to burners for reheat combustion chambers - Google Patents

Abstract

1,273,017. Burners for gas turbines. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. 1 Oct., 1969 [2 Oct., 1968], No. 48289/69. Heading F4T. [Also in Division F1] A gas turbine engine has a reheat combustion chamber containing a fuel vaporizing device heated by turbine exhaust gases and supplied with air from a by-pass or other separate duct. In one arrangement, Figs. 1, 6, the re-heat chamber 1 of a gas turbine jet propulsion engine contains angularly spaced vaporizing devices 20 each having a feed pipe 21 receiving liquid fuel from an injector 25 and air from an annular bypass duct 3. The fuel in pipe 21 is vaporized by heat exchange with the exhaust gases from turbine 2 and the vaporized fuel/air mixture discharges into the reheat chamber 1 in an upstream direction through the openings 26 of angularly spaced pipes 23. The pipe 21 is divided by partitions 27 into a number of compartments 28 each communicating with one of the pipes 23 and being aligned with a corresponding orifice of the fuel injector 25. The fuel flow through individual orifices can be selectively controlled so as to vary the relative fuel richness in compartments 28. Further air is supplied to the reheat chamber 1 from an annular continuation 13 of the by-pass duct 3 through openings 17, 18 in a heat shield 10. Air is also supplied from the by-pass duct 3 through hollow struts 12 to the interior 15 of a centre body 11 and is directed by nozzles 19 towards the inlet of a further vaporizing device 30. The latter comprises an annular V-section ring 31, Figs. 1, 3, supporting angularly spaced feed pipes 32 each partitioned by a wall 37. Some of the air from nozzles 19 enters the feed pipes 32 together with fuel from injectors 39 and flows through pipes 34 to upstream directed outlets 35, the fuel being vaporized in the process. The ring 31 includes apertures 38 for the passage of air and combustion gases. In a modification, Fig. 8, the vaporizing device 44 is supported from centre body 11 and rceeives an airflow f 3 which has been tapped from the by-pass duct 3 and used as cooling air. In further modifications, Figs. 10, 11 (not shown), the vaporizing device (46) comprises a partitioned annular distribution pipe (49) supplied with fuel and bypass air through a partitioned feed pipe (47). The distribution pipe (49) connects with radially disposed pipes (48a, 48b) which have upstream facing outlets (50a, 50b). The pipes (48a, 48b) may be supported from the heat shield 10 or between two concentric annular V-section gutters (53, 54). In a further arrangement, Fig. 7 (not shown), angularly spaced star shaped vaporizing devices of the kind shown in Fig. 6 are supported between annular V-section gutters (41, 42) connected by radial V-section stays (43).