GB996659A - Improvements in or relating to gas turbine engines - Google Patents

Abstract

996,659. Gas turbine engines; combustion chambers. J. SZYDLOWSKI. March 18, 1964 [May 3, 1963],.No. 11393/64. Headings F1G and F1L. A gas turbine engine comprises air compressing means, combustion equipment and turbine means, the combustion equipment having means for supply thereto of liquid fuel and natural gas, the supply of liquid fuel and gaseous fuel being controlled by means of an isodromic speed regulator which is adapted to maintain at a constant value the rotational speed of the turbine. The speed regulator is as described and claimed in Specification 860,283. The engine shown comprises an axial flow compressor 2 and a centrifugal compressor 3 in series flow, combustion equipment comprising an outer casing 7 and an inner flame tube, the combustion gases being discharged therefrom through a guide vane assembly comprising vanes 9 having cooling air flow passages therethrough, on to a turbine comprising a rotor assembly 10, 10a. The flame tube is annular and comprises a first radially-disposed portion 15 and a second axially-extending portion 16, liquid fuel being discharged into the flame tube portion 15 through a rotating nozzle assembly 35 to which fuel is supplied through a duct in the shaft 14 on which the turbine and compressor assemblies are mounted; gaseous fuel is discharged into the flame tube portion 15 through orifices 34. Primary combustion air is supplied into the flame tube portion 15 through openings 37 in the upstream wall 36 and through openings 33 in the downstream wall 32, the latter portion of air passing from the plenum space 6 through the passages 17 in the inlet guide vanes 9 to the space 28 before discharging into the flame tube through the orifices 33. Gaseous fuel is supplied through lines 45, 46 to a manifold 47, 48, from which it passes through a plurality of pipes 52 which extend radially through the hollow guide vanes 9 to spaces 25 formed in the wall 21, 22, the fuel then passing into spaces 26 from which it discharges through orifices 34. Ignition means 55 comprising a fuel inlet 56 is disposed within the air jacket space 6 as shown in Fig. 1. Dilution air is supplied into the flame tube space 16 through ducts 42. The fuel control apparatus is shown in Fig. 5, the liquid fuel line being indicated at 60 and the natural gas fuel line at 65. A first control valve 59 is disposed in the line 60 and a similar valve 64 in the line 65, the valve 59 being controlled by a first diaphragm 61 which is subject at one side to pressure of fuel downstream of the valve 59 and at its other side is acted on by a spring. The valve 59 is also controlled by a second diaphragm 67 which is subject at one side to pressure of the gaseous fuel in line 65 downstream of the valve 64, which pressure is communicated through line 69. The valve 64 in the gaseous fuel line is similarly controlled by fuel pressure downstream of the valve 64 and by pressure of liquid fuel downstream of the valve 59, the latter pressure being communicated through line 70. Further valves 71, 72, are disposed in the fuel lines 60, 65, respectively, and by-pass passages 75, 76 having electro-magnetic control valves 73, 74 are disposed there around. The valve 73 is controlled in dependence on pressure of gaseous fuel in line 65 which is sensed by diaphragm 81; should the pressure in line 65 fall below a predetermined value, the contact 79 will close and the solenoid 77 will act to open the by-pass valve 73. The by-pass valve 74 is similarly controlled by pressure in the liquid fuel line 60. The fuel supply apparatus comprises also further valves 91 and 92 disposed in the liquid fuel line 60 and gaseous fuel line 65 respectively. The valve 91 is controlled by a piston 89 and valve 92 by a spring-loaded piston 90, the positions of the pistons being controlled by means of a spool valve 83 the axial position of which is controlled by an isodromic governor 87 acting against a control spring 88, the loading of which may be adjusted. In a further embodiment, the valves 59 and 64 are controlled only by the pressures downstream thereof communicated through lines 62 and 66; also the two valves 91, 92 are controlled by a single piston the axial position of which is controlled by means of an isodromic governor 87 which controls the axial position of a spool valve such as 83. Specifications 686,908 and 693,217 also are referred to.