GB925633A - Combustion chamber suitable for a gas turbine engine - Google Patents

Abstract

925,633. Generating combustion products under pressure. SCHWEIZERISCHE LOKOMOTIV-UND MASCHINENFABRIK. Aug. 26, 1959 [Aug. 26, 1958], No. 29203/59. Class 51 (1). A combustion chamber, for example, for a gas-turbine engine, comprises a flame tube disposed within an air casing so as to afford an annular air flow passage therebetween, a fuel nozzle and primary air inlet being provided at the inlet end of the flame tube. The central portion of the annular air flow passage is formed as a diffuser, the wall of the flame tube forming the inner wall of the diffuser comprising a first upstream portion which is imperforate and a second downstream portion in which openings are provided for inflow of secondary air, the openings comprising an upstream ring of openings and a closely adjacent downstream ring of openings of larger diameter than the upstream openings. The equipment shown comprises a flame tube having a divergent frusto-conical portion 13, a convergent frustoconical portion la and a divergent frustoconical outlet portion 18, the flame tube being disposed within a tubular air casing 5 so as to provide an annular air space 15 therebetween, the portion L of which between the flame tube wall portion la and the casing affords a diffuser. Air inlet openings 16, 17 are provided in the convergent wall portion la of the flame tube, the holes in the first upstream row 16 being of diameter d1 and those in the second downstream row 17 being d2; there are twice as many holes in the first row as in the second, a hole in the second row being disposed axially downstream of a hole in the first row. Ratios of the diameters d1, d2 of the inlet holes 16, 17 and of the internal diameter Do of the air casing 5 are given. Air flows through a duct 6 which divides into two streams 6a, 6b, the stream 6a flowing through guide vanes 7 and swirl vanes 8 to enter the primary combustion zone adjacent the outlet of the fuel nozzle 4. The air stream 6b divides, some entering the flame tube as primary air and the remainder flowing through the diffuser passage 15 and entering the flame tube through openings 16, 17 as secondary air. The sections of the flame tube are held together resiliently by means of spring 20 which bears against a tube 22 which transmits the spring force to the swirl vane ring 8 and tube 24 to the flame tube sections. The flame tube is located axially at its outlet end and is also resiliently supported radially at 26. Gaseous fuel may be supplied through the inlet branch 6a.