Turbojet fuel supply system with fuel recycling
AssigneeSociete Nationale d'Etude et de Construction de Moteurs d'Aviation "S.N.E.C.M.A."
InventorsGerard C. H. Dehan, Michel G. A. Doublier, Gerard Greiner
Life of this patent
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Abstract
In a turbojet fuel supply system in which a controlled flow of fuel ql is diverted from between the high pressure pump and the feed flow regulator and recycled upstream of the high pressure pump in order to maintain a substantially constant pressure differential cross the feed regulator, a flow qc is tapped from the hot flow ql for return to the fuel tank and to allow a correspondingly greater portion of cold fuel from the low pressure pump to be mixed with the recycled hot fuel ql delivered to the high pressure pump. If necessary, the tapped hot flow qc is mixed with a flow of cold fuel qf tapped from the low pressure pump output to form a lukewarm mixture qr for return to the tank.
Claims9
Fuel supply system for a turbojet aero-engine comprising:
- (a) a fuel tank;
- (b) a booster pump disposed in said fuel tank;
- (c) a low pressure pump for receiving fuel delivered from said fuel tank by said booster pump;
- (d) a high pressure pump for receiving fuel delivered by said low pressure pump;
- (e) a feed flow regulator for receiving fuel delivered by said high pressure pump;
- (f) a fuel injection system for receiving a regulated supply of fuel from said feed flow regulator;
- (g) a first branch for diverting a diverted flow of fuel q1 from beteen said high pressure pump and said feed flow regulator and recycling said diverted flow of fuel q1 to said supply system at a point P1 between said low pressure pump and said high pressure pump, the fuel in said diverted flow of fuel q1 being hot after passage through said high pressure pump;
- (h) a control valve in said first branch for controlling said diverted flow of fuel q1 so as to maintain substantially constant the difference between the fuel pressures upstream and downstream of said feed flow regulator;
- (i) a second branch for tapping a tapped flow of hot fuel qc from said diverted flow of fuel q1 at a point P2 in said first branch between said control valve and said point P1;
- (j) return means for returning said tapped flow of hot fuel qc to said fuel tank;
- (k) a third branch for tapping a flow of cold fuel qf from a point P0 between said low pressure pump and said point P1;
- and
- (l) a mixing device for mixing said tapped flow of hot fuel qc with said flow of cold fuel qf to form a flow qr of lukewarm fuel for return to said fuel tank by said return means,
- whereby the temperature of said fuel delivered to said high pressure pump is lowered as a result of the portion of cold fuel received from said low pressure pump increasing by an amount equal to said tapped flow of hot fuel qc tapped from said diverted flow of fuel q1 recycled to said point P1 for delivery to said high pressure pump with said cold fuel from said low pressure pump.
Dependencies are inferred from the claim text.