RU2476702C2 - Gas turbine engine fuel feed system - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed system comprises electrically driven fuel pump fuel feed main line communicated with pump outlet with booster-shutoff valve or means to distribute fuel among atomiser manifold, and additional line communicating pump inlet with its outlet. Proposed fuel pump is a displacement pump with fuel feed amount varied by varying electric drive rpm. Extra pipeline is provided with fuel constant flow valve composed of jet arranged in said line and spring-loaded control slide valve. Jet inlet and outlet are communicated with slide valve free and spring-loaded chambers. Slide valve groove edge and slide valve sleeve orifice make variable-section channel in said extra line.

EFFECT: higher accuracy of fuel proportioning, fuel bleeding for engine fuel system components.

2 cl, 2 dwg

Description

Known systems for supplying fuel to gas turbine engines (GTE) based on the use of a volumetric fuel pump with a controlled electric drive [1].

To ensure tightness in the main fuel supply line until the pump reaches the required flow rate, a shut-off valve or fuel distributor for the engine injector manifolds is installed at the pump outlet to the main line.

Dosing of fuel into the main combustion chamber of a gas turbine engine is carried out by controlling the speed of the pump shaft driven by a controlled electric drive, and a positional electric drive is used instead of hydromechanical devices using fuel from the pump as a working fluid to change the position of regulatory bodies in the gas-air duct of the engine.

The advantage of such a system is a significant simplification or elimination of the drive box of the engine assemblies, elimination of excess fuel bypass and its associated overheating when working at height, as well as the absence of movable pump drive shaft seals in the case of using a wet type electric motor.

However, in such a fuel supply system it is not possible to provide additional fuel extraction to the engine starting nozzles during its start-up, since such selection will lead to a change in the fuel supply to the main line. In addition, the use of a controlled electric drive to change the position of regulatory bodies in the gas-air path of the engine is often difficult or impossible due to the high temperature in the area of their installation, which requires the use of hydromechanical devices and the organization of appropriate fuel selection from the pump, which is also impossible in this system.

The disadvantages also include the difficulty of accurately metering the minimum fuel consumption due to the very low volumetric efficiency of the pump at low speeds.

The technical task of the claimed invention is to provide the possibility of additional fuel withdrawals to the starting nozzles and the needs of the engine gas-air duct control system and to increase the accuracy of fuel metering from minimum to maximum values.

To solve this technical problem, the fuel supply system to the gas turbine engine includes an electric drive volumetric fuel pump with a change in the fuel supply due to a change in the rotational speed of the electric drive and the main fuel supply line connected to the pump outlet with a shut-off valve or fuel distributor for the nozzle manifolds, according to the invention, an additional line is introduced from the pump outlet to its inlet with a constant fuel flow valve installed in it in the form, for example , A play set in an additional line of the nozzle and a spring-loaded regulator valve, wherein the inlet and outlet orifice are connected with the cavities and the free ends of the spring-loaded spool, respectively, and the groove on the spool edge with the hole in the hub of the spool forms a further variable section line channel.

In addition, a backup valve is installed in the additional line behind the constant flow valve, in front of which the fuel line is allocated to the starting nozzles or actuators of the automatic control system (ACS) of the engine.

Figure 1 shows a structural diagram of a system for supplying fuel to the engine with an output for fuel withdrawals; figure 2 is a diagram without fuel withdrawals.

In the diagram (Fig. 1), the components of the system are conventionally shown in blocks: a gas turbine engine with a generator built-in or mounted on the drive box, gas-air duct regulating organs, an information-measuring system, an ACS control unit (BUSAU), an electric drive control unit (ECU), an electric drive a fuel pump (ETN) with a position sensor of the rotor of the electric motor (DPR), a fuel pump (NT) with a filter element (FE) at the input and the relationship between them. The fuel is supplied to the main combustion chamber of the gas turbine engine from the outlet of the pump along the line 1 with a stop-valve 2 installed in it or a fuel distributor (Fig. 2) to the nozzle manifolds. To carry out fuel withdrawals, an additional line 3 was introduced into the system from the pump (NT) outlet to its inlet with a constant flow valve 4 and a backup valve 5 installed in it, between which a fuel outlet 6 was made for sampling the flow rate G _m to the starting nozzles and gas-regulating organs tract gas turbine engine. The constant flow valve 4 is, for example, a combination of a nozzle 7 installed in an additional line and an adjustable spring-loaded spool 8, while the inlet and outlet of the nozzle are connected to the cavities of the free and spring-loaded ends of the spool, respectively, and the groove edge 9 on the spool together with the hole 10 in the sleeve the spool forms a channel of variable cross section in the trunk.

The constant flow valve is calculated and adjusted to the maximum required fuel take-off from the pump or to the minimum necessary fuel bypass to ensure stable and accurate dosing of the minimum fuel consumption in the absence of taps by increasing the minimum pump shaft speed.

A nozzle 11 and a shut-off valve 12 are installed in the start-up flow line G _m to the start-up nozzles. Fuel is supplied to the line of the start-up nozzles when a signal is received from the BUSAU to the solenoid valve (EMC) of the start-up nozzles. If you need accurate dosing of fuel consumption on the starting nozzles instead of the nozzle 11, an additional constant flow valve is installed.

The setting pressure of the shut-off valve 5 in the auxiliary line is selected based on the specified technical characteristics and the maximum required pressure for the control of the engine control system, and the setting pressure of the shut-off valve 2 or fuel distributor for the nozzle manifolds in the flow line G _{m of the} main circuit or main line must be above this value.

The system operates as follows. The total fuel consumption at the outlet of the volumetric pump is determined by the speed of the shaft driven by the electric drive. The constant flow valve 4 provides a constant fuel consumption in an additional line of fuel withdrawals. The fuel consumption in the additional line 3 is determined by the hydraulic resistance of the nozzle 7 and the pressure drop across it, which is supported by an approximately constant spring-loaded spool 8 of the constant flow valve 4. When the fuel consumption in the additional line is equal to a predetermined value, the spool is in equilibrium under the influence of the differential pressure at the inlet and the outlet of the nozzle and the spring opposing it.

With a decrease in fuel consumption in the additional line, the pressure drop across the jet 7 decreases, and the tightening force of the spool spring 8 overcomes the force from the pressure drop. The spool is displaced, while the edge 9 of the groove on the spool opens the hole 10 in the spool sleeve, increasing the channel bore and reducing the hydraulic resistance of the additional line.

Fuel consumption is redistributed in the direction of increasing consumption in an additional line, the pressure drop on the jet 7 is restored, and the spool comes into a new state of equilibrium.

The operation of the system with an increase in fuel consumption in the additional line flows in a similar way. This maintains an approximately constant supply of fuel to the additional line.

The resulting flow rate G _{m of the} main circuit is determined by the difference in flow rates at the pump outlet and the flow rate to the additional line 3, which makes it possible to regulate the flow to the main line by changing the speed of the electric drive.

When the starting fuel supply or control devices are turned on, part of the fuel that passed through the constant flow valve goes to these consumers, the rest of the fuel through the backup valve 5 enters the pump inlet. In this case, a pressure corresponding to the tightening of its spring is maintained in front of the backup valve.

If there is no need for fuel withdrawals (Fig. 2), a backup valve 5 is not required, while a predetermined constant fuel consumption is bypassed directly through a constant flow valve 4 to the pump inlet.

The cessation of fuel supply to the main line can be achieved by turning off the power or by reducing the speed of the pump shaft from the electric drive to a value at which the total fuel consumption at the pump outlet becomes equal to or less than the fuel consumption in the additional line. Due to a higher setting of the opening pressure of the shut-off valve 2 or the fuel distributor for the nozzle manifolds in the main line as compared to the shut-off valve 5 in the secondary line (or in its absence), the fuel supply to the main line is cut off.

At the same time, all the necessary fuel withdrawal requirements are provided.

When the power is turned off or the drive is stopped, the fuel supply stops both in the main and in the secondary line.

Implementation of the proposed scheme for supplying fuel to a gas turbine engine using a constant flow valve allows, in addition to providing additional fuel selection for start-up nozzles and the needs of the gas-air duct control system, to ensure improved fuel metering due to regulation in the region of a higher volumetric efficiency of the pump at a higher speed electric drive.

Information sources

1. Belkin Yu.S. Control systems based on a controlled electric drive // Improving gas turbine engine control systems and developing new hardware solutions: TsIAM report. - M., 1999 .-- S. 420-422.

Claims (2)

1. The system for supplying fuel to a gas turbine engine, comprising a volumetric electric drive fuel pump with a change in fuel supply due to a change in the speed of the electric drive and a main fuel supply line connected to the pump outlet with a shut-off valve or fuel distributor for the nozzle manifolds, characterized in that an additional line was introduced into it from the pump outlet to its inlet with a constant fuel flow valve installed in it in the form, for example, of a combination of Modes line nozzle and spring-loaded regulator valve, wherein the inlet and outlet orifice are connected with the cavities and the free ends of the spring-loaded spool, respectively, and the groove on the spool edge with the hole in the hub of the spool forms a further variable section line channel. 2. The system according to claim 1, characterized in that a backup valve is installed in the additional line behind the constant flow valve, in front of which the fuel withdrawal line is assigned to the starting nozzles or actuators of the automatic engine control system.

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