Engine fuel system for use with composite aircraft

Patent metadata

Field	Value
Publication number	US-11261793-B2
Application number	US-201916587686-A
Country	US
Kind code	B2
Filing date	Sep 30, 2019
Priority date	Dec 18, 2015
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine includes feeding un-heated fuel from a fuel tank to the gas turbine engine, by using an ejector pump to draw the fuel from the fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine. Fuel from the main fuel line is bled and directed to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump. The bleed fuel flow is then passed through a hydrophobic fuel screen located upstream of the motive flow pump.

First claim

The invention claimed is:

1. A method of pumping fuel in a fuel system of a composite aircraft having a gas turbine engine, the method comprising:
feeding un-heated fuel in the fuel system, including using an ejector pump to draw the fuel from a fuel tank and feeding the fuel through an engine fuel pump within a main fuel line upstream of the gas turbine engine;
bleeding fuel from the main fuel line and directing the bleed fuel flow to the ejector pump via a motive flow pump assembly, the motive flow pump assembly including a motive flow pump generating a motive flow for the ejector pump; and
passing the bleed fuel flow through a hydrophobic fuel screen located upstream of the motive flow pump, the hydrophobic fuel screen having a plurality of fluid flow openings of dimensions to prevent passage of particles greater than a selected threshold size and to allow passage of liquids through the openings.

2. The method of claim 1 , further comprising feeding the motive flow generated by the motive flow pump through an outlet fuel screen disposed downstream of the motive flow pump and upstream of the ejector pump.

3. The method of claim 2 , further comprising providing the outlet fuel screen with a hydrophobic coating.

4. The method of claim 3 , further comprising providing the outlet fuel screen with a polytetraflouroethylene coating.

5. The method of claim 2 , further comprising providing the outlet fuel screen with fluid flow openings therein having a size that is greater than or equal to the fluid flow openings in the hydrophobic fuel screen.

6. The method of claim 1 , further comprising providing the hydrophobic fuel screen with a polytetraflouroethylene coating.

7. The method of claim 1 , wherein the hydrophobic fuel screen includes a cylindrical basket defining an interior chamber, the method further comprising allowing the bleed fuel flow to pass from the interior chamber through a porous wall of the cylindrical basket.

8. The method of claim 1 , further comprising feeding the un-heated fuel through a heat exchanger located in series with the engine fuel pump in the main fuel line.

9. The method of claim 8 , further comprising bleeding the bleed fuel from the main fuel line upstream of the heat exchanger.

Assignees

• Pratt & Whitney Canada

Inventors

• Shafique Harris
• Waddleton David

Classifications

• F02C7/236 Primary

  Fuel delivery systems comprising two or more pumps · CPC title

• F02C7/224

  Heating fuel before feeding to the burner · CPC title

• F02C9/36

  characterised by returning of fuel to sump (F02C9/38 takes precedence) · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• B64D37/10

  to facilitate fuel pressurisation · CPC title