GB1103933A - Improvements in or relating to fuel ignition in turbo-jet engines - Google Patents

Abstract

1, 103, 933. Jet propulsion plant; reciprocating pumps. M.A.N. TURBO G.m.b.H. July 13, 1965 [July 15, 1964], No. 29748/65. Headings F1A and F1J. A gas turbine jet propulsion engine has a reheat igniting arrangement comprising two nozzles one of which is mounted in the combustion chamber upstream of the turbine to produce a "hot streak" which ignites the second nozzle in the jet pipe downstream of the turbine thus igniting the adjacent reheat nozzles. Fuel is supplied to the ignition nozzles by a device comprising a charging piston 3 movable in a cylinder 2. When reheat ignition is required, a hydraulic pressure is applied to the left of a piston 13 displacing the piston to the right against a spring 15. This allows valve 11 to move off its seat and place high-pressure fuel line 200 in communication with the right hand side of charging piston 3 by way of chamber 20 and passage 21. Piston 3 is thus forced to the left to urge fuel through non-return valve 5 to the ignition nozzle in the jet pipe and, an instant later, through annular groove 25 and non-return valve 8 to the ignition nozzle upstream of the turbine. As piston 3 moves further to the left it obturates valve 8 but continues to force fuel through valve 5 until it reaches a position, Fig. 2 (not shown), in which it opens a valve 7 to allow the remaining fuel to flow out from cylinder 2 into the engine low-pressure fuel system 100. The position of annular groove 25 is such that the "hot streak" through the turbine is prevented from burning too long and the issuing of unburned fuel from the nozzle in the jet pipe is prevented. For recharging the device, pressure is removed from the left of piston 13 so that spring 15 relaxes, thus closing valve 11. Spring 4 then returns piston 3 to the right hand end of cylinder 2 thus drawing in low-pressure fuel through a non- return valve 6. Cooling is effected by fuel flowing through bores 22, 23 and 24.