EP2753811A1

EP2753811A1 - Fuel system using dual pressure hi-speed centrifugal pump arrangement

Info

Publication number: EP2753811A1
Application number: EP20120823474
Authority: EP
Inventors: Martin Augustine CLEMENTS
Original assignee: Eaton Corp
Current assignee: Eaton Corp
Priority date: 2011-08-15
Filing date: 2012-08-15
Publication date: 2014-07-16
Also published as: CN103958856A; WO2013025818A1; WO2013025818A9; EP2753811A4; US20140219826A1; CN103958856B

Abstract

An improved system for providing fuel uses a centrifugal pump arrangement that provides dual pressure. The dual pressure pump assembly includes a centrifugal pump for supplying pressurized fluid to an associated downstream use, and an auxiliary pump stage for selectively boosting pressure of delivered flow. The auxiliary pump stage in one preferred arrangement includes a start and turbo-pump stage where inlet fuel from an associated airframe is fed to a centrifugal pump portion of the turbo-pump that outlets to an inlet of the centrifugal pump. The auxiliary pump stage in another arrangement includes a recirculation passage communicating with the outlet of the high-speed centrifugal pump and the turbine, and the outlets from the start and turbo-pump stage feed an inlet of the high speed centrifugal pump, and a flow valve is disposed in the recirculation passage. In still another arrangement, the auxiliary pump stage includes an electric motor for start-up.

Description

FUEL SYSTEM USING DUAL PRESSURE HI-SPEED

CENTRIFUGAL PUMP ARRANGEMENT

BACKGROUND

[0001 ] This disclosure relates to a fuel system for a jet engine application, and particularly to a jet engine fuel pump arrangement that supplies different pressure nee system.

[0002] Jet engine applications require high take-off pressure output. When ap high-speed centrifugal pump technology to these jet engine applications, the pump gei becomes excessively large for the balance of operating condition requirements (e.g., i< climb, etc.). The excessively large pump, in turn, creates a series of system issues rev around the thermal impacts on the system.

[0003] Jet engines typically use hydraulic power generated by the engine fuel power many variable geometry actuators of the engine. Many current jet engine fuel 5 incorporate a component such as a servo fuel heater or similar means to keep the fuel : the actuators (servo supply) above fuel system icing temperatures, for example ideally F, to avoid potential issues associated with ice formation. The servo fuel heater is typ: located downstream of a fuel filter and upstream of an actuation control module whict pressurized fluid for low and high pressure actuators.

[0004] Consequently, a need exists for a system and method that better addres: competing system demands.

SUMMARY

[0005] An improved system for providing fuel to a jet engine application is pre using a centrifugal pump arrangement that provides dual pressure.

[0006] The system includes a dual pressure pump assembly having a centrifug; for supplying pressurized fluid to an associated downstream use. An auxiliary pump s operatively associated with the centrifugal pump for selectively boosting pressure of ( flow to the associated downstream end-use.

[0007] The auxiliary pump stage in one preferred arrangement includes a start pump stage where inlet fuel from an associated airframe is fed to a centrifugal pump j the turbo-pump that outlets to an inlet of the centrifugal pump.

[0008] The auxiliary pump stage in one arrangement includes a recirculation ] communicating with the outlet of the high-speed centrifugal pump and the turbine, an outlets from the start and turbo-pump stage feed an inlet of the high speed centrifugal a flow valve is disposed in the recirculation passage.

[0009] The auxiliary pump stage in an another arrangement includes a recircu passage communicating with the outlet of the high-speed centrifugal pump and the tui flow valve is disposed in the recirculation passage), the outlet from the high speed cer pump feeds (i) an inlet of a centrifugal start pump and (ii) selectively feeds the turbine the turbo-pump (depending on the flow valve), and an outlet of the start pump boosts pressure of the fuel directed downstream to the associated end use, and the outlet iron turbine is directed to an inlet of the high speed centrifugal pump.

[00010] The auxiliary pump stage in one arrangement preferably includes an el motor for start-up.

[0001 1 ] The auxiliary pump stage preferably includes a recirculation passage re portion of flow from an outlet of the centrifugal pump and directing the flow portion t of the centrifugal pump.

[00012] In another arrangement, the auxiliary pump stage further includes a val recirculation passage for controlling flow therethrough.

[00013] The auxiliary pump stage further includes an ejector pump in a preferre arrangement that is interposed between the valve and the centrifugal pump inlet for re< flow portion from the centrifugal pump outlet and raising a pressure of inlet flow direc centrifugal pump inlet. [00014] One benefit of the disclosure is the ability to provide different pressure from the centrifugal pump arrangement.

[00015] Another advantage of the disclosure relates to potentially reducing syst weight, and envelope requirements by eliminating the need for a servo fuel heater or a heat exchanger.

[00016] Still another benefit resides in the ease with which the centrifugal pumj arrangement can be incorporated into existing system designs.

[00017] Still other features and benefits of the present disclosure will become a upon reading and understanding the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[00018] Figure 1 schematically illustrates a fuel system that includes a first pref embodiment of a two-pressure level pump arrangement.

[0001 ] Figure 2 schematically illustrates a fuel system that includes a second p embodiment of a two-pressure level pump arrangement.

[00020] Figure 3 schematically illustrates a fuel system that includes a two-pres pump.

[00021] Figure 4 schematically illustrates a preferred dual pressure high-speed c pump arrangement in a high pressure output mode.

[00022] Figure 5 schematically illustrates a preferred dual pressure high speed c pump arrangement in a low pressure output mode.

DETAILED DESCRIPTION

[00023] Turning first to Figure 1, there is shown at least a portion of a fuel systi includes a pump assembly or pump arrangement 102. The pump arrangement 102 reci fuel from an airframe 104 and delivers the fuel at a higher pressure to at least one dow end use or end uses 106, 108. More specifically, the first end-use 106 is generally refe a fuel control so that fuel is delivered by the pump arrangement through a fuel/oil hea 1 10, and subsequently to a fuel filter 1 12, where it is then delivered to the fuel control Typically, fuel passes through the fuel filter 1 12 as directed to the fuel control 106 wr is combusted as represented at 1 14. A portion of the pressurized fuel from the pump arrangement 102 is likewise fed through the fuel/oil heat exchanger 1 10 and fuel filtei delivery to the second end use, also referred to as an actuation control module 108. T provides the desired pressurized fluid for low-pressure actuation represented at 120, o pressure actuation as indicated at 122. A servo fuel heater or heat exchanger 124 is pi upstream of the actuation control module 108 in order to sufficiently heat the fuel abo system icing temperature, for example on the order of 40° F. However, and for reasoi described in greater detail below, the servo fuel heater 108 may be eliminated with a corresponding savings in cost, weight, and envelope size requirements (and thus is rer with a dashed lead line).

[00024] The pump arrangement 102 incorporates a dual pressure level high-spe centrifugal pump that combines a high-speed centrifugal pump stage 130, and a start a pump stage 140, a control or flow valve 150 to selectively provide recirculation of a p the pressurized fluid from the high speed centrifugal pump 130 to the turbine portion ( turbo-pump, and an electric motor 160 to assist the start and turbo-pump stage. Gener valve 150 is used to select the use or non-use of the turbo-pump 140 schematically loc at an inlet 132 of the high-speed centrifugal pump stage (Figure 1) or at a discharge/oi of the high-speed centrifugal pump stage (Figure 2). When the control valve 150 is of valve permits the application of a motive flow from the high-speed centrifugal stage d 134 to the turbo-pump motive port 142 and thereby causes the turbo-pump stage to rai pressure to the inlet 132 of the high-speed centrifugal pump. More particularly, a cent pump portion outlet 146 of the turbo-pump 140 is pressurized to a first pressure level I application of motive power from the electric motor 160 and or from the turbine portic turbo-pump stage when the control valve 150 is open. An outlet 148 of the turbine poi turbo-pump stage 140 is also connected or communicated to the inlet 132 of the high-s centrifugal pump stage. In turn, the high-speed centrifugal stage raises the pressure an in a higher pump discharge pressure at outlet 134 that is fed to the downstream end us 108.

[00025] When the valve 150 is closed, the valve impairs the application of a m< from the high-speed centrifugal stage discharge 134 to the turbo-pump motor port 141 thereby causes the turbo-pump stage 140 to act as a pass through for inlet or discharge to/ from the high speed centrifugal stage without an increase to the inlet/discharge pres to/from the high-speed centrifugal stage. In turn, the high-speed centrifugal stage 130 pressure of the fluid (e.g. fuel) and results in a reduced pump discharge pressure comp when there is motive flow applied.

[00026] While operating in a high-pressure mode (i.e. with the valve 150 open) speed centrifugal pump stage 130 generates considerable fuel heating. During fuel sy operating conditions where fuel temperatures is nearing the fuel system icing point, th pressure mode of the pump arrangement 102 can be selectively employed to maintain system temperature above the icing point without the use of supplemental servo suppl via the servo fuel heater 124. In this manner, the servo fuel heater 124 and the associe plumbing may be removed from the system with a cost, weight, and substantial envelc reduction.

[00027] In addition, an electric motor 160 is used to start the engine and power pump stage during low engine shaft 180 speed operation. When starting a jet engine, speeds are insufficient to result in any significant buildup of pressure by the typical hi; centrifugal pump stage 130. By using the electric motor 160 to power the turbo-pump during the low engine shaft speed regime, sufficient pressure can be established with t pump stage thereby getting the engine to start and advance to the idle power setting w! shaft speed is sufficient to obtain the needed pressure and flow output from the high-s] centrifugal pump stage 130 alone. The system architectures of Figures 1 and 2 show a arrangement that does not require the use of isolation valves to direct the start stage fk would be required in other schemes. Further, the type of pump used for the start stage centrifugal style and therefore works well with the same fuel control system as is used engine operation above start-up. As the high-speed centrifugal pump 130 is capable o some hydraulic power at low engines shaft speeds, albeit at low pressure, this hydraul source can be used in conjunction with the electric motor to obtain the engine start, th minimizing the size of electrical power required by the turbo-pump start feature.

[00028] As is evident in Figure 2 (where primed suffixes (') are used with like i numerals to refer to like components), inlet fuel 104' is provided to the centrifugal pui 132 'and directed from the high-speed centrifugal pump outlet 134'toward the turbo-pi 140'. A portion of that flow is inlet to the centrifugal pump portion of the turbo-pumr where the pressure is further raised before being directed to downstream end uses 106 Depending on the position of the flow valve 150', a portion of the flow fr m the outle high-speed centrifugal pump 130' is fed to the turbine portion of the turbo-pump stagt selectively assist the electric motor operatively associated with the turbo-pump stage, flow from the turbo-pump stage is then recirculated toward the inlet of the high-speed pump stage.

[00029] It is also represented in the figures that the pump arrangement and spec example, the valve 150 and the electric motor, are connected to an electronic control u 170. This is not intended to indicate that other components of the fuel system are not i to the ECU but is merely representative that operation of a flow valve can be a simple operation, or may be a variable or modulated flow, that is controlled by the ECU 170. still other components have been removed for ease of illustration and description, alth< be appreciated that the dual pressure high-speed centrifugal pump arrangement providi different pressure needs of the system in a manner that is reliable, convenient, and cosi

[00030] Turning to Figures 3-5, like reference numerals in the "200" series to re components (e.g., pump arrangement 102 of Figures 1 and 2 is referred to as pump am 202) the pump arrangement 202 incorporates a dual pressure level high-speed centrifu; that combines a high-speed centrifugal pump stage 230, and an ejector pump stage 24C control valve 250 to select the function of the ejector stage. Generally, the control vab selects the use or non-use of the ejector pump 240 that is schematically illustrated as bi located at the inlet to the high-speed centrifugal pump 230. When the control valve 25 as represented in Figure 4, the valve permits the application of a motive flow from an c of the high-speed centrifugal stage discharge to the ejector pump motive port 242, anc causes the ejector pump 240 to raise the inlet pressure to an inlet 234 of the high speei centrifugal pump 230. In turn, the high speed centri ugal pump driven by shaft 236 ci pressure rise to the working fluid (i.e. fuel) which results in a higher pump discharge ] the outlet 232.

[00031] When the valve 250 is closed (Figure 5), the valve impairs the applicat motive fluid from the high speed centrifugal pump outlet 232 to the ejector pump mot 242, and thereby causes the ejector pump 240 to act as a pass through for inlet flow fn inlet 204 (which may be received from a separate electric start pump 260 that is separ; by electric power) to the high-speed centrifugal pump 230 without an increase to the i pressure at inlet 234 to the high-speed centrifugal pump. In turn, the high-speed centr pump 230 applies or increases the pressure to the fluid and results in a reduced pump < pressure compared to when there is motive flow applied (i.e., when the valve is open z 4)·

[00032] While operating in the high-pressure mode with the valve 250 open, th< speed centrifugal pump 230 generates considerable fuel heating. During fuel system c conditions where fuel temperature is nearing the fuel system icing point, the high-pres of the pump can be selectively employed to maintain fuel system temperature above tl point without the use of supplemental servo supply heating via the servo fuel heater 21 3). In this manner, the servo fuel heater 224 and its associated plumbing may be remo the system with cost, weight, and substantial envelope volume reduction.

[00033] It is also represented in Figure 3 that the pump arrangement and specifi example, the ejector flow valve 250 operation is connected to an electronic control uni 270. This is not intended to indicate that other components of the fuel system are not < to the electronic control unit but is merely representative that operation of a flow valvt be simple on-off, or may be a variable or modulated flow that is controlled by the ECl Likewise, still other components have been removed for ease of illustration and descri] although it will be appreciated that the dual pressure high-speed centrifugal pump arras provides for different pressure needs of the system in a manner that is reliable, convei cost-effective.

[00034] This written description uses examples to describe the disclosure, inch best mode, and also to enable any person skilled in the art to make and use the disclos patentable scope of the disclosure is defined by the claims, and may include other exa occur to those skilled in the art. Such other examples are intended to be within the so claims if they have structural elements that do not differ from the literal language of tl or if they include equivalent structural elements with insubstantial differences from th language of the claims. It is also noted that each feature of each specific embodiment herein is not considered essential to that specific embodiment, and that features disclo embodiment can be added r substituted with another embodiment.

Claims

I claim:

1. A dual pressure pump assembly for a fuel system comprising:

a centrifugal pump for supplying pressurized fluid to an associated use; and

an auxiliary pump stage operatively associated with the centrifugal pui selectively boosting pressure of delivered flow to the associated downstream end-use.

2. The dual pressure pump assembly of claim 1 wherein the auxiliary pur includes a start and turbo-pump stage where inlet fuel from an associated airframe is 1 second centrifugal pump that outlets to an inlet of the centrifugal pump.

3. The dual pressure pump assembly of claim 2 wherein the start and turb stage includes a recirculation passage communicating with the outlet of the turbo-pun an inlet of the start stage.

4. The dual pressure pump assembly of claim 3 wherein the start and turb stage includes a valve in the recirculation passage to selectively control flow from the centrifugal pump outlet to a turbine portion of the turbo-pump stage.

5. The dual pressure pump assembly of claim 2 wherein the auxiliary pun includes an electric motor for start-up.

6. A method of selectively boosting pressure of delivered flow to an assoc downstream end-use using a dual pressure pump assembly for a fuel system that inclu centrifugal pump and an auxiliary pump stage, the method comprising

supplying pressurized fluid to the associated downstream use from the centrifu and

selectively boosting pressure of delivered flow from the centrifugal pump with auxiliary pump stage.

7. The method of claim 6 wherein the auxiliary pump stage includes a sta turbo-pump stage, and the method further includes feeding inlet fuel from an associate to a second centrifugal pump that outlets to an inlet of the centrifugal pump.

8. The method of claim 7 wherein the start and turbo-pump stage include recirculation passage, and the method further includes communicating with the outlet turbo-pump to feed an inlet of the start stage.

9. The method of claim 8 wherein the start and turbo-pump stage include: the recirculation passage, and the method further includes selectively controlling flow high-speed centrifugal pump outlet to a turbine portion of the turbo-pump stage.

10. The wherein the auxiliary pump stage includes an electric motor, and tl includes using the electric motor for start-up.