US3645094A - Fuel-pumping system with vortex-type flow resistor - Google Patents

Fuel-pumping system with vortex-type flow resistor Download PDF

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US3645094A
US3645094A US3645094DA US3645094A US 3645094 A US3645094 A US 3645094A US 3645094D A US3645094D A US 3645094DA US 3645094 A US3645094 A US 3645094A
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fuel
pump
engine
flow
pressure
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Alfred M Suggs
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Motors Liquidation Co
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Motors Liquidation Co
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D9/00Priming; Preventing vapour lock
    • F04D9/04Priming; Preventing vapour lock using priming pumps; using booster pumps to prevent vapour-lock
    • F04D9/06Priming; Preventing vapour lock using priming pumps; using booster pumps to prevent vapour-lock of jet type
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/206Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/2087Means to cause rotational flow of fluid [e.g., vortex generator]
    • Y10T137/2098Vortex generator as control for system
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/206Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/2087Means to cause rotational flow of fluid [e.g., vortex generator]
    • Y10T137/2109By tangential input to axial output [e.g., vortex amplifier]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/8593Systems
    • Y10T137/85978With pump
    • Y10T137/86131Plural

Abstract

A fuel-pumping system for a gas turbine engine includes a jet pump in the fuel tank, a boost pump, a pressure pump, and a fuel control to control the fuel supply from the pressure pump to the engine. The jet pump is energized by fuel diverted from the outlet of the pressure pump through a static vortex-type flowresisting device having a pressure drop proportional to flow raised to a power greater than two. This device reduces the amount of increase in fuel returned to the jet pump which would otherwise occur under high-pressure discharge conditions of the pressure pump.

Description

, United States Patent VORTEX-TYPE FLOW RESISTOR Alfred M. Suggs, Indianapolis, Ind.

General Motors Corporation, Mich.

June 4, 1970 Inventor:

Assignee: Detroit,

Int. Cl. ..F02c 9/10 Field ofSearch 60/3928; l37/569,565, 81.5

References Cited UNITED STATES PATENTS 10/1969 Rupertf. ..l37/81.5 1/1968 Rupert..... .60/39.28 UX 5/1970 Chow ..l37/81.5

12/1970 Freeman ..137/81.5

Suggs 51 Feb. 29, 1972 j [54] FUEL-PUMPING SYSTEM WITH FOREIGN PATENTS OR APPLICATIONS 726,496 10/ 1942 Germany ..137/569 Primary Examiner-Clarence R. Gordon AttorneyPaul Fitzpatrick and Jean L. Carpenter [57] ABSTRACT A fuel-pumping system for a gas turbine engine includes a jet pump in the fuel tank, a boost pump, a pressure pump, and a fuel control to control the fuel supply from the pressure pump to the engine. The jet pump is energized by fuel diverted from the outlet of the pressure pump through a static vortex-type flow-resisting device having a pressure drop proportional to flow raised to a power greater than two. This device reduces the amount of increase in fuel returned to the jet pump which would otherwise occur under high-pressure discharge conditions of the pressure pump.

5 Claims, 2 Drawing Figures ENGINE FUEL E CONTROL 7 ENGINE Patented Feb. 29-, 1972 FUEL CONTROL INVENTUR. fllfim ZZZ 5&5

FUEL-PUMPING SYSTEM 'WITH VORTEX-TYPE FLOW RESISTOR The inventionherein described was made in the course of work under a Contract or subcontract thereunder with the Department of Defense.

DESCRIPTION My invention relates to fuel-pumping systems such, for example, as are employed to supply fuel to aircraft gas turbine engines and particularly to fuel systems of the sort in which a jet pump in the fuel tank is employed to provide a small pressure head in the fuel flowing from the reservoir to the fuelpumping devices of the engine to prevent cavitation in the fuel pumps.

Where a jet pump is so used, it is energized by fuel under pressure diverted from the main fuel pump of the engine. The flow must be sufficient to secure adequate inlet pressure at the engine driven pumps at a low fuel flow rate and corresponding relatively low pressure of fuel delivered to the engine. As the engine fuel consumption increases, and with it the pressure of the fuel supplied, the flow to energize the jet pump increases. Normally, it will increase beyond what is needed, so that there is a-wasteof pumped fuel under pressure.

According to my invention, a flow resisting or regulating device. of a static vortex flow type is interposed in the energizing fuel line to the jet pump. Such a device has the characteristic that the drop in pressure through the flow resistor is proportional to flow rate as to a power greater than two; for example, the exponent may be of the order of 2.4. With such a device, the increase in flow at higher pressures is less than would be the case with a simple restriction or orifice in the jet pump energizing fuel line.

This has advantages in that there is less power extraction from the engine to drive the fuel pumps, less temperature rise in the fuel, and a reduction in weight in the drive gearing to the enginefuel pumps is permitted. This is accomplished with ease and economy, since the flow resistor is a vortex device with no moving parts and of very simple structure.

The principal objects of my invention are to achieve the im provements in fuel systems set out in the preceding paragraph, and particularly to improve the efficiency and reduce the weight of fuel systems for gas turbine engines.

The nature of my invention and its advantages will be clear to those skilled in the art from the succeeding detailed description and accompanying drawings of the preferred embodiment of the invention.

FIG. 1 is a schematic diagram of a gas turbine engine fuel system;

FIG. 2 is a sectional view of a vortex flow resistor.

Referring to FIG. 1, the engine 2 in the preferred embodiment is assumed to be a gas turbine engine of any usual type, although the fuel system illustrated is applicable to engines of other sorts. Fuel is supplied to the engine from a tank or reservoir 3 through a fuel line 4, a centrifugal boost pump 6, a boost pump outlet line 7, a positive displacement pressure pump 8, a fuel line 10, a fuel control 11, and an-engine fuel line 12. The fuel control may embody mechanisms of the usual sort for providing control of the power level of the engine and safeguarding it from overfueling, underfueling, overspeed, and other hazards. Such fuel controls usually include some sort of manual input indicated at 14 to regulate engine power level.

In a gas turbine engine, the pressure of the fuel delivered to the engine increases with fuel flow and increases also with increases of ambient pressure. Thus, for example, during full throttle operation at low altitudes the fuel pressure may be of the order of 1,000 p.s.i., whereas at low power levels at high altitude the fuel pressure may be much less, perhaps 200 p.s.i. The main or pressure pump 8 supplies the fuel at sufiicient pressure to force it into the engine and the boost pump 6 supplies the fuel to the pump 8 at a substantial pressure to avoid cavitation in pump 8. The engine includesan auxiliary drive shaft 16 which is connected by the schematically represented gearing to the boost pump 6 through a shaft 18, the main pump 8 through a shaft 19, and the fuel control 11 through a shaft 20. The engine thus drives the pumps and provides an input of engine speed to the fuel control for overspeed control and fuel regulation purposes.

The system illustrated is of the sort in which the fuel pump is of a fixed displacement type with an output roughly proportional to engine. speed. The fuel pump output must at all times exceed the maximum engine requirements for any engine rotational speed. Thus, ordinarily, there is an excess of fuel pumped, some of which is returned by the fuel control through a bypass line 22 to the input of the main fuel pump. Some of the fuel delivered by the main pump 8 is also diverted through a jet pumpenergizing fuel line 19 to the high-pressure fuel inlet 24 of the jet pump. The jet pump, as is well known. is a device of the nature of an injector in which the jet of highpressure fuel from the nozzle or inlet 24 entrains fuel fromthe tank 3 with it and pumps it into the line 4 under sufficient pressure to avoid cavitation in the boost pump 6.

The system as so far described may be considered to be conventional. In the conventional system the amount of flow through line 19 would ordinarily be controlled by a fixed orifice or by the size of the jet nozzle 24 or, in general, by means such that the flow through line 19 is proportional to the square root of pressure drop from the pump outlet to the tank 3. My invention lies in the addition to the conventional system of a static flow control means or vertex type flow-resistor 26 in the fuel line 19.

The device 26 is a static device; that is, one with no moving parts and one which has the characteristic that the pressure drop due to flow through the device is proportional to the rate of flow raised to a power greater than two. Specifically a desirable exponent may be of the order of 2.4. The preferred form of such a device is illustrated in FIG. 2.

The flow resistor 26, which will be referred to hereafter as a vortex device, comprises a housing 27 which defines a chamber 28 of circular or spiral cross section as illustrated and a tangential or substantially tangential inlet 30 to the chamber 28 to which the return line 19 is connected to jet the fuel into the chamber 28 for swirling movement around the axis of the chamber. The outlet from chamber 28 is through a circular outlet 31 on the axis of the chamber which connects with the line 19 downstream of the vortex device 26. The outlet 31 is not intended as a throttling device in the ordinary senseand is not primarily a restriction in the line. The resistance to flow comes from the swirling movement of the fuel in the chamber 28, the fuel tending to pursue a free vortex flow, that is, a flow in which the swirl component of velocity of the fluid is inversely proportional to the radius. Of course, the velocity departs somewhat from this proportionality as the fuel swirls inward toward the outlet 31 because of frictional losses and viscosity effects but, as is well known, with such a vortex device a substantial back pressure is developed with the rapidly swirling fuel flowing over the edge of the outlet 31. A device of this sort has a pressure drop characteristic which may be expressed as follows: the pressure drop through the device is proportional to the weight of flow per unit time to an exponent which is greater than two, and the value of which depends upon the physical dimensions and velocity of flow entering the device. In a specific device which has been calibrated and which is of appropriate size for a moderate sized gas turbine engine of the order of 5,000 horsepower, the chamber 28 is approximately 6inches in diameter and six-tenth inch in axial length and the outlet is approximately nine-tenth inch in diameter. With inlets of A- and %-inch diameter the exponent has been found by test to be approximately 2.37. Higher or lower values of the exponent may be arrived at by modification of dimensions.

The significance of this exponent greater than two may be appreciatedby consideration of the operating situation in a fuel system of the sort and described here. If the line 19 were throttled simply by an orifice and we assume a return flow through line 19 of 5,000 pounds per hour with a pressure drop of 200 p.s.i. there would then be a flow of 1 1,200 pounds per hour with a pressure drop of 1,000 psi. This is approximately the range of pressures that might be encountered in a typical gas turbine fuel system. Now, assume a vortex device having the exponent 2.37 is substituted for the fixed orifice and the vortex device is designed for a 200 p.s.i. drop at 5,000 pounds per hour as with the orifice previously mentioned. Flow with 1,000 psi. drop increases only to 9,850 pounds per hour. This is a decrease in the return of flow of 1,350 pounds per hour or, in other words, a reduction of 22 percent in the excess flow. The result can be a corresponding reduction in the capacity of the pumps 7 and 8 and the accessory drive system to operate the pumps. Also a useful reduction in the power diverted from the engine to operate the fuel system, and a reduction in fuel temperature rise which is desirable.

The detailed description of the preferred embodiment of my invention for the purpose of explaining its principles is not to be considered as limiting or restricting the invention, since many modifications may be made by the exercise of skill in the art.

-lclaim:

1. A fuel-pumping system for an engine comprising a fuel reservoir, a primping pump of the jet type in the reservoir, a boost pump supplied by the jet pump, a pressure pump supplied by the boost pump, the boost and pressure pumps being driven by the engine, an outlet line to the engine supplied by the pressure pump, fuel control means in the outlet line effective to control the rate of supply of fuel to the engine, and a return line from the pressure pump to the priming pump to supply operative fuel to the priming pump; in combination with a vortex-cavity-type flow resistor in the return line having a pressure drop proportional to flow through the resistor raised to an exponent greater than two.

2. The combination of a fuel-consuming engine, rotary fuelpumping means driven by the engine, fuel control means connected between the said pumping means and the engine effective to control fuel flow to the engine, and means for supplying fuel to the pumping means including a fuel reservoir and a jet pump in the reservoir, in combination with an energizing fuel line from the outlet of the pumping means to the inlet of the jet pump and static flow control means in the energizing fuel line having a characteristic AP proportional to W where AP is pressure drop, W is fuel flow in weight per unit time, and the exponentx has a value greater than 2.

3. A combination as recited in claim 2 in which the exponent x is greater than 2.3.

4. A fuel-pumping system for an engine comprising a fuel reservoir, a priming pump of the jet type in the reservoir, rotary fuel-pumping means supplied by the priming pump and driven by the engine, an outlet line to the engine supplied by the rotary pumping means, and a return line from the rotary pumping means to the jet-type pump to supply operative fuel to the priming pump; in combination with static flow control means in the return line having a pressure drop proportional to flow through the flow control means raised to an exponent greater than two.

5. A system as recited in claim 4 in which the static flow control means is a vortex cavity device with a single inlet and a single outlet, the inlet being tangential and the outlet being axial.

mm: A.

22 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3,645,094 Dated Februry 29, 1972 lnvencork's) Alfred M; Suggs It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 66, "5/8-1nch" should read 3/8-inc'h Column 3, line 22, "primping" should read priming Signed and sealed this 26th day of December 1972.

(SEAL) Attest:

EDWARD M.FLET0HER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of P tents

Claims (5)

1. A fuel-pumping system for an engine comprising a fuel reservoir, a primping pump of the jet type in the reservoir, a boost pump supplied by the jet pump, a pressure pump supplied by the boost pump, the boost and pressure pumps being driven by the engine, an outlet line to the engine supplied by the pressure pump, fuel control means in the outlet line effective to control the rate of supply of fuel to the engine, and a return line from the pressure pump to the priming pump to supply operative fuel to the priming pump; in combination with a vortex-cavity-type flow resistor in the return line having a pressure drop proportional to flow through the resistor raised to an exponent greater than two.
2. The combination of a fuel-consuming engine, rotary fuel-pumping means driven by the engine, fuel control means connected between the said pumping means and the engine effective to control fuel flow to the engine, and means for supplying fuel to the pumping means including a fuel reservoir and a jet pump in the reservoir, in combination with an energizing fuel line from the outlet of the pumping means to the inlet of the jet pump and static flow control means in the energizing fuel line having a cHaracteristic Delta P proportional to Wx where Delta P is pressure drop, W is fuel flow in weight per unit time, and the exponent x has a value greater than 2.
3. A combination as recited in claim 2 in which the exponent x is greater than 2.3.
4. A fuel-pumping system for an engine comprising a fuel reservoir, a priming pump of the jet type in the reservoir, rotary fuel-pumping means supplied by the priming pump and driven by the engine, an outlet line to the engine supplied by the rotary pumping means, and a return line from the rotary pumping means to the jet-type pump to supply operative fuel to the priming pump; in combination with static flow control means in the return line having a pressure drop proportional to flow through the flow control means raised to an exponent greater than two.
5. A system as recited in claim 4 in which the static flow control means is a vortex cavity device with a single inlet and a single outlet, the inlet being tangential and the outlet being axial.
US3645094D 1970-06-04 1970-06-04 Fuel-pumping system with vortex-type flow resistor Expired - Lifetime US3645094A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783903A (en) * 1970-06-16 1974-01-08 Secr Defence Fluidic pressure ratio control
US4073136A (en) * 1975-09-12 1978-02-14 Rolls-Royce (1971) Limited Fuel system for gas turbine engines
US4833880A (en) * 1988-10-26 1989-05-30 Allied-Signal Inc. Fluidic set point amplifier apparatus and method, and uses thereof
US4887628A (en) * 1987-08-28 1989-12-19 United Kingdom Atomic Energy Authority Fluidic apparatus
US5311907A (en) * 1993-05-27 1994-05-17 The United States Of America As Represented By The United States Department Of Energy Vortex diode jet
US20040020539A1 (en) * 2002-07-30 2004-02-05 Po-Lin Liao Bilateral power pump unit
US20080202470A1 (en) * 2005-01-04 2008-08-28 Lothar Dickenscheid Fuel Supply System for a Motor Vehicle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE726496C (en) * 1940-06-01 1942-10-14 Heinkel Flugzeugwerke Gmbh E Foerdereinrichtung for fuel, Kuehlstoff o. The like., In particular in aircraft
US3366370A (en) * 1965-12-06 1968-01-30 Honeywell Inc Control apparatus
US3474670A (en) * 1965-06-28 1969-10-28 Honeywell Inc Pure fluid control apparatus
US3511257A (en) * 1968-09-12 1970-05-12 Westinghouse Electric Corp Vortex type throttling valve apparatus
US3545468A (en) * 1969-05-06 1970-12-08 Bowles Eng Corp Liquid level controller employing vortex valve

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE726496C (en) * 1940-06-01 1942-10-14 Heinkel Flugzeugwerke Gmbh E Foerdereinrichtung for fuel, Kuehlstoff o. The like., In particular in aircraft
US3474670A (en) * 1965-06-28 1969-10-28 Honeywell Inc Pure fluid control apparatus
US3366370A (en) * 1965-12-06 1968-01-30 Honeywell Inc Control apparatus
US3511257A (en) * 1968-09-12 1970-05-12 Westinghouse Electric Corp Vortex type throttling valve apparatus
US3545468A (en) * 1969-05-06 1970-12-08 Bowles Eng Corp Liquid level controller employing vortex valve

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783903A (en) * 1970-06-16 1974-01-08 Secr Defence Fluidic pressure ratio control
US4073136A (en) * 1975-09-12 1978-02-14 Rolls-Royce (1971) Limited Fuel system for gas turbine engines
US4887628A (en) * 1987-08-28 1989-12-19 United Kingdom Atomic Energy Authority Fluidic apparatus
US4833880A (en) * 1988-10-26 1989-05-30 Allied-Signal Inc. Fluidic set point amplifier apparatus and method, and uses thereof
US5311907A (en) * 1993-05-27 1994-05-17 The United States Of America As Represented By The United States Department Of Energy Vortex diode jet
US20040020539A1 (en) * 2002-07-30 2004-02-05 Po-Lin Liao Bilateral power pump unit
US6899130B2 (en) * 2002-07-30 2005-05-31 Po-Lin Liao Bilateral power pump unit
US20080202470A1 (en) * 2005-01-04 2008-08-28 Lothar Dickenscheid Fuel Supply System for a Motor Vehicle
US7644702B2 (en) * 2005-01-04 2010-01-12 Siemens Aktiengesellschaft Fuel supply system for a motor vehicle

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