GB712843A - Vaporising and combustion systems of gas turbine engines - Google Patents

Abstract

712,843. Generating combusition products under pressure. ARMSTRONG SIDDELEY MOTORS, Ltd. Nov. 17, 1952 [Dec. 6, 1951], No. 28598/51. Class 51 (1). [Also in Group XI] A combustion system for a gas turbine engine has an auxiliary combustion chamber supplied with air and fuel so proportioned that there is no uncombined oxygen in the effluent therefrom, the rest of the fuel being introduced into the effluent so that it will be completely vaporized and the whole then passing to the combustion system. Compressed air is supplied to the auxiliary combustion chamber 19, Fig. 1, through a duct 12 from which the air passes through two transverse passages 13 (one only of which is shown) to a mixing and burning chamber 14 as disclosed in Specification 577,865. The air is swirled in the chamber 14 with fuel supplied through two pipe lines 16 and passes upstream through a sharp edged opening 17 to the closed end 18 of the chamber 19 where combustion is initiated by a torch igniter 20. The main fuel is delivered through a pipe 25 to an annular space 26 surrounding the downstream end of the chamber 19, and having an annular outlet channel 29 from which the fuel passes through a plurality of circumferentiallly spaced apertures controlled by needle valves 30 which are opened by the fuel pressure against the action of springs 31. The fuel then forms a film along the inner surface of the outlet nozzle 21 of the combustion chamber 19, and becomes partially vaporized by contact with the hot combustion products, the vaporization being completed in a chamber 22 having a sharp-edged inlet opening for causing turbulence in the entering gases. From the chamber 22 the combustible mixture passes through an outlet 23 to a pipe (not shown) leading to distributing means for the combustion chamber system. In an alternative construction the main fuel is not passed through an annular space surrounding the chamber 19 but is passed through a vaporizing coil disposed in a cylindrical outlet through which the combustion products pass from the chamber 19, the vaporized fuel mixing with said combustion products at the discharge end of the cylindrical outlet. Fig. 4 illustrates a part of an annular combustion chamber for a gas turbine engine in which a vapour generator as described with reference to Fig. 1 is supported by struts 51 within the upstream end of annular walls 47, 48 forming the inlet to an annular combustion chamber built of overlapping walls 47, 47a, and 48, 48a &c. provided with inlets for cooling air between the overlapping portions. The chamber 22 communicates with an annular chamber 52 from which the vaporized fuel passes to the combustion zone through fine openings in its downstream wall 54. Secondary air is supplied through apertures 57 in walls 58 supporting the chamber 52. In two further embodiments a vapour generator having a cylindrical outlet containing a vaporizing coil is mounted outside and supplies fuel vapour in one construction to an annular combustion chamber, and in the other to a series of annularly arranged "can" type combustion chambers each having a perforated burner tube of ring form.