Bleed valve resonator drain

A bleed valve includes a valve body which includes an aperture. A resonator is in fluid communication with the aperture in the valve body. A drain valve is in fluid communication with the resonator.

BACKGROUND

During certain operating conditions for the gas turbine engine, it may be advantageous to bleed compressor air off of the compressor section through a bleed duct by opening a bleed valve. In particular, bleeding air from the compressor section can reduce instability in the compressor section that may result from surges in pressure. However, air flowing across the bleed duct when the bleed valve is closed may create a resonance in the bleed duct. The resonance could cause vibrational waves to travel through compressor blades adjacent the bleed duct resulting in unwanted stress on the compressor blades. Therefore, there is a need to prevent the formation of vibrational waves traveling through the bleed duct when the bleed valve is closed.

SUMMARY

In one exemplary embodiment, a bleed valve includes a valve body which includes an aperture. A resonator is in fluid communication with the aperture in the valve body. A drain valve is in fluid communication with the resonator.

In a further embodiment of the above, the drain valve includes a body portion that at least partially surrounds a slider.

In a further embodiment of any of the above, the slider is configured to move in an axial direction.

In a further embodiment of any of the above, there is a spring for biasing the slider relative to the body portion.

In a further embodiment of any of the above, the slider includes an engagement portion for engaging a static structure on a gas turbine engine.

In a further embodiment of any of the above, the slider includes a seal portion that includes at least one O-ring for selectively opening an aperture in the resonator.

In a further embodiment of any of the above, the valve body is located radially inward from the resonator.

In another exemplary embodiment, a gas turbine engine includes a compressor section. A bleed duct is in communication with the compressor section. A bleed valve is in communication with the bleed duct which includes an aperture in a valve body. A resonator is in fluid communication with the aperture and a drain valve is in fluid communication with the resonator.

In a further embodiment of any of the above, the bleed valve is a 2.5 bleed valve for a gas turbine engine.

In a further embodiment of any of the above, the bleed valve is located adjacent an aft stage of a low pressure compressor.

In a further embodiment of any of the above, the drain valve includes a body portion that at least partially surrounds a slider.

In a further embodiment of any of the above, the slider is configured to move in an axial direction.

In a further embodiment of any of the above, there is a spring for biasing the slider relative to the body portion.

In a further embodiment of any of the above, the slider includes an engagement portion for engaging a static structure on a gas turbine engine.

In a further embodiment of any of the above, the slider includes a seal portion including at least one O-ring for selectively opening an aperture in the resonator.

In a further embodiment of any of the above, the bleed valve is located radially inward from the resonator.

In another exemplary embodiment, a method of operating a gas turbine engine includes bleeding compressed air through a bleed duct, counteracting a resonant frequency with a resonator adjacent the bleed duct and draining a fluid from the resonator through a drain valve.

In a further embodiment of any of the above, the drain valve includes a body portion at least partially surrounding a slider with the slider configured to move in an axial direction.

In a further embodiment of any of the above, there is a spring for biasing the slider relative to the body portion.

In a further embodiment of any of the above, the slider includes an engagement end for engaging a static structure on the gas turbine engine.

DETAILED DESCRIPTION

FIG. 1illustrates a schematic view of a gas turbine engine10. In the illustrated example, the gas turbine engine10is an industrial gas turbine engine circumferentially disposed about a central, longitudinal engine axis A. In this disclosure, radial or radial direction is relative to the engine axis A unless otherwise specified.

The gas turbine engine10includes, in series order from an axial front to an axial rear, a low pressure compressor section16, a high pressure compressor section18, a combustor section20, a high pressure turbine section22, and a low pressure turbine section24. In the illustrated embodiment, a power turbine section26is a free turbine section disposed aft of the low pressure turbine24and drives a power turbine drive shaft28(FIG. 2).

Incoming ambient air30entering the gas turbine engine10becomes pressurized air32in the low pressure compressor16and the high pressure compressor18. Fuel mixes with the pressurized air32in the combustor section20prior to ignition and combustion of the fuel. Once the fuel has combusted, combustion gases34expand through the high pressure turbine section22, the low pressure turbine section24, and through the power turbine section26. The high and low pressure turbine sections22and24drive high and low pressure rotor shafts36and38, respectively, which rotate in response to the combustion products and thus rotate the attached high and low pressure compressors18and16. The power turbine section26may, for example, drive an electrical generator54, pump, or gearbox through the power turbine drive shaft28(FIG. 2).

A low pressure turbine exhaust case40is positioned between the low pressure turbine section24and the power turbine section26. The turbine exhaust case40defines a flow path for gas exhausted from low pressure turbine section24that is conveyed to power turbine26. The turbine exhaust case40also provides structural support for the gas turbine engine10.

A basic understanding and overview of the various sections and the basic operation of the gas turbine engine10is provided inFIG. 1. However, this disclosure is applicable to all types of gas turbine engines, including those with aerospace applications and industrial applications.

As shown inFIG. 2, an example industrial gas turbine engine assembly50including a gas turbine engine52, such as the example gas turbine engine10described above, mounted to a structural land based frame to drive the electrical generator54.

FIG. 3illustrates a cross-section view of the low pressure compressor16. In the illustrated example, the low pressure compressor16includes a core flow path with four stages of rotating blades62separated from each other by vanes64. A bleed valve66is located downstream or aft of a fourth stage blade62. In the illustrated example, the bleed valve66is a 2.5 bleed valve. However, the bleed valve66may be located at a different position in the gas turbine engine10.

The bleed valve66selectively directs a portion of the core flow path through a bleed duct68or the entire core flow path though the high pressure compressor18. The bleed valve66selects between the bleed duct68and the high pressure compressor18depending instability of flow in the core flow path based on an operational state of the gas turbine engine10, such during starting conditions, transient conditions, and reverse thrust conditions.

While the bleed valve66is closed, gases from the core flow path are prevented from exiting the core flow path through the bleed duct68. Gases flowing across the bleed duct68may create a resonance in the bleed duct68. The resonance may cause vibrational waves to travel axially forward and damage the blades62in the low pressure compressor16nearest the bleed duct68. In the illustrated example, the blade62nearest the bleed duct68would be the fourth or aft most stage in the low pressure compressor16. The frequency of the vibrational waves may be changed to prevent damage by altering the properties of the bleed duct68, such as a length or volume of the bleed duct68, or by incorporating a resonator.

The bleed valve66may be in communication with a compressor control system70, such as a portion of the Electronic Engine Control (“EEC”) for controlling stability of the low pressure compressor16during starting conditions, transient conditions, and reverse thrust conditions. The EEC is the primary interface with the power plant and includes communication with various systems, such as engine interference, vibration monitoring units, maintenance systems, and electronic instrument systems. The bleed valve66may be directed to open by the EEC to bleed fourth stage air out of the core flow path of the low pressure compressor16through the bleed duct68.

FIG. 4illustrates a cross-section view of the bleed valve66. The bleed valve66includes a bleed valve body72and seals76that seal the bleed valve66relative to a low pressure compressor case98. A resonator74is located adjacent the bleed valve66on a radially outer side of the bleed valve66.

An actuator78may drive the bleed valve body72in an axially forward or upstream direction to release gases from the core flow path through the bleed duct68to reduce the amount of gases entering the high pressure compressor18. The bleed valve body72includes a radially extending aperture80that receives a manifold82. The manifold82is located on a radially outer side of the bleed valve body72and includes a collar portion84defining an aperture85that extends at least partially into the aperture80in the bleed valve body72. Although only a single collar portion84is shown in the illustrated example, multiple collar portions84could be located on a single manifold82and the bleed valve body72could include a corresponding number of apertures80to receive the multiple collar portions84.

The resonator74includes a resonating chamber86defined by a first resonator body portion88on a radially inner side, a second resonator body portion90on a radially outer side, and a third or intermediate resonator body portion92located radially between the first resonator body portion88and the second resonator body portion90. The first, second, and third resonator body portions88,90, and92are secured together by fasteners96. The first resonator body portion88includes an aperture94that is aligned with the apertures80and85so that the resonator74is in fluid communication with the bleed duct68. The resonator74changes the acoustic properties of the bleed duct68to prevent the formation of a resonant frequency in the bleed duct68.

In order to increase the efficiency of the gas turbine engine10, it can be advantageous to inject water into the low pressure compressor16during operation. Any of the injected water that does not evaporate or travel into the high pressure compressor18will be left behind in the low pressure compressor16. As shown inFIG. 5, the bleed valves66and resonators74are circumferentially spaced around an entire perimeter of the low pressure compressor case98. Therefore, the injected water or water from another source may collect in the bleed valves66and the resonators74along the bottom portion of the low pressure compressor16.

As shown inFIGS. 4 and 6-7, a drain valve100is located on a radially outer side of the resonator74. In the illustrated example, the drain valve100is a spring loaded valve, however, other types of actuated valves could be used in place of the spring loaded valve, such as a solenoid valve operated by the compressor control system70.

In the illustrated example, the drain valve100includes a body portion102, a slider108, and a spring116. The body portion102has a generally elongated cylindrical shape and is attached to the second resonator body portion90. Although the body portion102is shown as a unitary piece, the body portion102could be formed from multiple pieces. The body portion102includes an inlet aperture104on a radially inner side that is circumferentially and axially aligned with a resonator drain opening106in the second resonator body portion90.

The slider108is at least partially located within the body portion102and includes a biasing portion110on a first end, an engagement portion112on a second opposite end, and a seal portion114between the first end and the second end.

The biasing portion110is located on the first end which is toward a forward or upstream end of the slider108. The spring116is located adjacent the biasing portion110and engages a shoulder111formed in the slider108to bias the slider108in the downstream or aft direction. In the illustrated example, the spring116is a helical spring and the biasing portion110of the slider108is generally cylindrical and extends through a central portion of the spring116.

The seal portion114is located in a mid-portion of the slider108and has a generally cylindrical cross section with a first face128on a first side and a second face130on a second opposite side. The first face128includes a first O-ring118surrounding the inlet aperture104and the second face130includes a second O-ring120surrounding an exit aperture122in the body portion102.

The engaging portion112of the slider108is located on the second end which is toward an aft or downstream end of the slider108. The engaging portion112is attached to the seal portion114on a proximal end and is configured to engage a flange126on the low pressure compressor case98on a distal end. The engaging portion112extends through a slider aperture124in an aft end or downstream end of the body portion102to facilitate reciprocating movement through the slider aperture124. In the illustrated example, the engaging portion112has a cylindrical cross section, however, the engaging portion112could have a rectangular or other shaped cross section. Although the slider aperture124does not include a seal in the illustrated example, an O-ring seal could be located in the slider aperture124to form a seal with the engaging portion112.

The drain valve100operates in response to movement from the actuator78. Therefore, when the bleed valve66is in a closed position, the drain valve100is also in a closed position to prevent leakage of any gases from the core flow path. Similarly, when the bleed valve66is in an open position, the any liquid that has collected in the resonator74can drain through the drain valve100along with a portion of the gases from the core flow path.

When the drain valve100and the bleed valve66are in a closed position, the seal portion114is aligned with the resonator drain opening106and the inlet aperture104to prevent leakage of any fluid from the resonator74. Therefore, the drain valve100is not able to release fluid from the resonator74when the bleed valve66is closed. The engaging portion112of the slider108is also in contact with the flange126to fully compress the spring116.

When the actuator78moves the bleed valve66in a forward direction to open the bleed valve66, the slider108moves axially aft relative to the body portion102due to the biasing force from the spring116on the biasing portion110. This increases the distance between the flange126and the body portion102and opens a fluid passage connecting the resonator drain opening106and the inlet aperture104with the exit aperture122.

Similarly, when the actuator78moves the bleed valve66in a downstream or aft direction to close the bleed valve66, the slider108moves axially forward relative to the body portion102and compresses the spring116. This closes the fluid passage connecting the resonator drain opening106and the inlet aperture104with the exit aperture122.