JP2013139783A - Turbine cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To meet the need for improvement of overall performance of a turbine.SOLUTION: A turbine cooling system is provided, and the system includes a compressor for supplying cooling air, a forward turbine rotor wheel space, a high-pressure packing seal (HPPS) bypass cavity, and a metering device. The forward turbine rotor wheel space is cooled by the cooling air supplied by the compressor. The HPPS bypass cavity is in fluid communication with and receives a portion of the cooling air from the compressor, and is in fluid communication with and supplies the cooling air to the forward turbine rotor wheel space. The metering device is in operable communication with the forward turbine rotor wheel space and the HPPS bypass cavity to modulate the cooling air supplied to the forward turbine rotor wheel space from the HPPS bypass cavity based on at least one operating condition of the turbine.

Description

  The present invention relates to a turbine cooling system, and in particular, to a turbine cooling system having a metering device for adjusting cooling air to a forward turbine rotor wheel space.

  In general, a gas turbine includes a compressor, a combustor, one or more fuel nozzles, and a turbine. Air flows into the gas turbine through the intake and is pressurized by the compressor. Next, the pressurized air is mixed with the fuel supplied from the fuel nozzle. The air-fuel mixture is supplied to the combustor at a specific mixing ratio for combustion. Combustion generates pressurized exhaust gas that drives the turbine blades.

  The turbine includes a rotor assembly having a plurality of turbine blades attached to a rotating disk. In operation, the turbine blades, rotating disk, and other components of the turbine are exposed to high temperatures. Cooling air is introduced to maintain the temperature of the turbine's internal components at an acceptable level. For example, cooling air can be supplied from the combustor plenum and can be used to cool the forward turbine rotor wheel space. The forward turbine rotor wheel space is located between the nozzle assembly and the compressor outlet diffuser of the turbine and may be exposed to some high temperatures experienced by the turbine. Cooling air is supplied to the front turbine rotor wheel space to operate in a predetermined temperature range suitable for the long term durability of the component. In certain operating conditions of this high ambient temperature, the volume of cooling air may be insufficient to maintain the forward turbine rotor wheel space in the desired temperature range for long term durability of the component.

  As one approach, the amount of cooling air supplied to the front turbine rotor wheel space is increased by removing the bore plug from the compressor discharge casing. Removing the bore plug results in some of the high pressure air flowing out of the compressor diverting to the front turbine rotor wheel space. However, this approach allows cooling air to flow into the front turbine rotor wheel space in all operating conditions without flow control. Therefore, when the bore plug is removed, cooling air is supplied more than necessary under the required operating conditions, leading to a decrease in the overall performance of the turbine. Furthermore, this approach also requires that the combustion system be removed in order to shut down the gas turbine and access the bore plug, which is cumbersome and inconvenient. In other approaches, an orifice can be provided to bypass some cooling air to the front turbine rotor wheel space. However, the orifice is generally sized to adequately cool the forward turbine rotor wheel space in the worst case. Therefore, since a large amount of cooling air is supplied by the orifice below the required operating condition, the overall performance of the turbine is also deteriorated.

  There is a need to improve the overall performance of the turbine.

  In one aspect of the invention, a turbine cooling system is provided that includes a compressor supplying cooling air, a forward turbine rotor wheel space, a high pressure packing seal (HPPS) bypass cavity, and a metering device. The front turbine rotor wheel space is cooled with cooling air supplied from a compressor. The HPPS bypass cavity receives in fluid communication with a portion of the cooling air from the compressor and supplies the front turbine rotor wheel space in fluid communication with the cooling air. The metering device is in operative communication with the forward turbine rotor wheel space and the HPP bypass cavity and regulates cooling air supplied from the HPPS bypass cavity to the forward turbine rotor wheel space based on at least one operating condition of the turbine. .

  These and other advantages and features will become apparent from the following description with reference to the drawings.

  The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims appended hereto. The above and other features and advantages of the present invention will be apparent from the following detailed description with reference to the accompanying drawings.

1 is a schematic diagram of an exemplary gas turbine system. FIG. FIG. 2 is a cross-sectional view of a portion of the compressor and turbine section shown in FIG. 1.

  This detailed description explains exemplary embodiments, together with advantages and features of the invention, by way of example with reference to the drawings.

  As used herein, the terms “module” and “submodule” refer to one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the described functionality. Refers to an application specific integrated circuit (ASIC), electronic circuit, processor (shared, dedicated, or group) and memory that performs.

  FIG. 1 shows a schematic diagram of an exemplary power generation system indicated by reference numeral 10. The power generation system 10 is a gas turbine system having a compressor 20, a combustor 22, and a turbine 24. The air flows into the power generation system 10 through the air inlet 30 disposed in the compressor 20 and is compressed by the compressor 20. The compressed air is then mixed with fuel by a fuel nozzle 34 located in the end cover (not shown) of the combustor 22. The fuel nozzle 34 injects the air-fuel mixture into the combustor 22 at a mixing ratio for combustion. High-temperature pressurized exhaust gas that drives turbine blades (not shown) disposed in the turbine 24 is generated by combustion. In one exemplary embodiment, the turbine 24 is configured as three stages having six rows of airfoils (not shown) arranged axially for flowing hot pressurized exhaust gas. In one embodiment, turbine 24 includes a first stage stator vane that forms a nozzle assembly (not shown).

  FIG. 2 is an enlarged view of a portion of the compressor 20 and turbine 24, showing an exemplary embodiment of a metering device 46. High pressure compressor discharge or cooling air is supplied from the compressor 20 and resides in and flows through the plenum 48. The front turbine rotor wheel space 50 is disposed between a nozzle assembly (not shown) and a compressor outlet diffuser (not shown). The temperature of the cooling air in the plenum 48 is lower than the temperature of the air in the front turbine rotor wheel space 50. In particular, the forward turbine rotor wheel space 50 may have some of the turbine 24 due to the unique position of the forward turbine rotor wheel space 50 in relation to some other component of the power generation system 10 such as the combustor 22. Tend to be subject to high temperatures. Accordingly, the cooling air present in the plenum 48 is used to cool the forward turbine rotor wheel space 50. The metering device 46 is used to adjust the amount of cooling air supplied to the front turbine rotor wheel space 50.

  Still referring to FIG. 2, cooling air from the plenum 48 flows through the cooling passage 52. A portion of the cooling air from the cooling passage 52 leaks through a pressure packing seal (HPPS) 56 to produce an HPPS leakage flow 58. The HPPS leakage flow 58 flows to the front turbine rotor wheel space 50 and is used to cool the front turbine rotor wheel space 50. The remaining cooling air that does not leak through the HPPS 56 flows to the HPPS bypass cavity 60. The metering device 46 is used to adjust the amount of cooling air supplied from the HPPS bypass cavity 60 to the front turbine rotor wheel space 50.

  In general, the metering device 46 is any type of variable orifice, such as a valve or solenoid, that can regulate the amount of cooling air supplied to the forward turbine rotor wheel space. In the exemplary embodiment shown in FIG. 2, the metering device 46 is a pintle valve 62, but it should be understood that other metering devices can be used as well. The valve 62 includes a needle or pintle 64. It is an elongated member that cooperates with an orifice 66 located in the wall 68 of the HPPS bypass cavity 60 and adjusts the amount of cooling air supplied to the front turbine rotor wheel space 50. In particular, in the illustrated exemplary embodiment, pintle 62 includes an inclined outer surface 70 and orifice 66 includes a corresponding inclined surface 72. The pintle 62 is selectively operated in the directions of D1 and D2 by the valve portion 74 of the pintle valve 62. In one embodiment, valve portion 74 is a piezo element that activates pintle 62 based on current, but it should be understood that other approaches can be used as well.

  The inclined outer surface 70 of the pintle 62 cooperates with the inclined surface 71 of the corresponding orifice 66 to adjust the amount of cooling air supplied to the front turbine rotor wheel space 50. That is, when the pintle 62 is operated in the first direction D1, the pintle 62 operates toward the orifice 66, and the amount of cooling air supplied to the front turbine rotor wheel space 50 is reduced. When the pintle 62 is actuated in the second direction D2, the pintle 62 is actuated away from the orifice 66, and the amount of cooling air supplied to the front turbine rotor wheel space 50 increases.

  The adjustment of the weighing device 46 is controlled by a control module 80 that communicates with the weighing device 46 via the data link 82. Data link 82 may be a wired or radio frequency (RF) data link that transmits control signals to metering device 46. The control module 80 includes control logic that sends control signals to the metering device 46 to increase or decrease the amount of cooling air supplied to the forward turbine rotor wheel space 50 based on specific operating conditions. For example, in the exemplary embodiment shown in FIG. 2, the control module 80 includes control logic that sends a control signal to the metering device 46 to operate the pintle 62 in the D1 and D2 directions. In particular, the control module 80 includes, but is not limited to, ambient temperature, total backflow margin of the turbine 24, bulk metal temperature of the turbine blade, front turbine rotor wheel space temperature, turbine emission requirements, and compressor discharge pressure. The amount of cooling air is increased or decreased based on at least one of the operating states.

  In one embodiment, the control module 80 connects to an environmental sensor (not shown) and receives temperature data. When the ambient temperature changes, the control module 80 includes control logic that sends control signals to the metering device 46 to increase or decrease the amount of cooling air to the forward turbine rotor wheel space 50. For example, if the ambient temperature increases, the control module 80 includes control logic that sends a control signal to the metering device 46 to increase the amount of cooling air supplied to the forward turbine rotor wheel space 50.

  The control module 80 may also include control logic for adjusting the amount of cooling air supplied to the front turbine rotor wheel space 50 based on the total backflow margin of the turbine 24. The total backflow margin is a differential pressure between the pressure of the cooling air and the pressure of the gas flow of the turbine 24, and generally a positive total backflow margin is maintained. The backflow margin can be a calculated value or a measured value. In one embodiment, if the backflow margin is insufficient, the control module 80 includes control logic that sends a control signal to the metering device 46 to increase the amount of cooling air supplied to the front turbine rotor wheel space 50. .

  The control module 80 can include control logic for adjusting the amount of cooling air supplied to the forward turbine rotor wheel space 50 based on the bulk metal temperature of the turbine blades (not shown). In particular, in one embodiment, if the turbine blade bulk metal temperature exceeds a predetermined temperature limit, the control module 80 sends a control signal to the metering device 46 to be fed into the forward turbine rotor wheel space 50. Includes control logic to increase the amount of cooling air.

  The control module 80 can include control logic for adjusting the amount of cooling air supplied to the front turbine rotor wheel space 50 based on the air temperature of the front turbine rotor wheel space 50. For example, in one embodiment, if the air temperature in the front turbine rotor wheel space 50 exceeds a predetermined temperature limit, the control module 80 sends a control signal to the metering device 46 to forward the front turbine rotor wheel space 50. The control logic which increases the quantity of cooling air supplied to is included.

  The control module 80 can also include control logic for adjusting the amount of cooling air supplied to the front turbine rotor wheel space 50 based on emissions requirements. For example, in one embodiment, when the power generation system 10 is in turndown mode, large air flow extraction out of the plenum 48 can be utilized to bypass the main combustion zone during load shedding and the combustor 22 (FIG. 1)), resulting in a reduced mass flow rate, resulting in a lower combustion temperature and reduced emissions. Accordingly, the metering device 46 is adjusted to increase the amount of cooling air supplied to the front turbine rotor wheel space 50.

  The control module 80 may also include control logic that adjusts the amount of cooling air to the forward turbine rotor wheel space 50 to provide compressor surge protection. In particular, when the power generation system 10 operates at a relatively large compressor pressure ratio, the pressure ratio of the compressor 20 may eventually exceed a limit value, leading to a rapid drop in compressor discharge pressure. The reduction in compressor discharge pressure results in flow separation known as compressor surge. Thus, the amount of cooling air to the front turbine rotor wheel space 50 is adjusted to provide a specific margin compressor discharge ratio away from the surge limit of the compressor 20. Adjusting the amount of cooling air supplied to the front turbine rotor wheel space 50 reduces, substantially reduces, or eliminates the need to recirculate some of the compressor discharge air to the compressor inlet by the intake bleed valve. . Recirculating a portion of the compressor discharge air to the compressor inlet is called a suction bleed heating system.

  The amount of cooling air to the forward turbine rotor wheel space 50 is adjusted in order to manage turbine rotor cooling and extend the component life of the turbine's internal components. Active adjustment of the amount of cooling air to the front turbine rotor wheel space 50 provides a power generation system 10 as compared to some techniques currently used to increase the cooling air to the front turbine rotor wheel space 50. The overall performance of For example, one way to increase the cooling air is to remove the bore plug from the compressor discharge casing. However, this causes the cooling air to flow into the front turbine rotor wheel space without being flow controlled in all operating conditions, reducing the overall performance of the turbine. In contrast, by actively adjusting the amount of cooling air to the front turbine rotor wheel space 50, the amount of cooling air can be adjusted based on specific operating conditions, resulting in overall performance of the power generation system 10 being improved. improves.

  Although the present invention has been described in detail with respect to only a limited number of embodiments, it should be understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate many variations, modifications, substitutions, or equivalent arrangements not described above, which correspond to the spirit and scope of the invention. In addition, while various embodiments of the invention have been described, it is to be understood that aspects of the invention can include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

20 Compressor 22 Combustor 24 Turbine 30 Inlet 34 Fuel nozzle

Claims (20)

In a turbine cooling system for a turbine,
A compressor for supplying cooling air;
A front turbine rotor wheel space cooled by the cooling air supplied from the compressor;
A high pressure packing seal (HPPS) bypass cavity that is in fluid communication with a portion of the cooling air from the compressor and that is in fluid communication with the cooling air and that is supplied to the front turbine rotor wheel space;
Operatively communicating with the front turbine rotor wheel space and the HPP bypass cavity, the cooling air supplied from the HPPS bypass cavity to the front turbine rotor wheel space based on at least one operating condition of the turbine A weighing device to be adjusted;
A turbine cooling system comprising:   The at least one operating condition is at least one of an environmental temperature, a total backflow margin of the turbine, a bulk metal temperature of a plurality of turbine blades, a temperature of a forward turbine rotor wheel space, a turbine emission requirement, and a compressor discharge pressure. The turbine cooling system of claim 1, wherein   The turbine cooling system of claim 1, wherein adjustment of the metering device is controlled by a control module in communication with the metering device.   The turbine of claim 3, wherein the control module includes control logic that transmits a control signal to the metering device to adjust the cooling air supplied to the front turbine rotor wheel space based on ambient temperature. Cooling system.   The turbine cooling system of claim 3, wherein the control module includes control logic that adjusts the cooling air supplied to the forward turbine rotor wheel space based on a bulk metal temperature of a plurality of turbine blades.   The turbine cooling system of claim 3, wherein the control module includes control logic that adjusts the cooling air supplied to the front turbine rotor wheel space based on an air temperature in the front turbine rotor wheel space.   The turbine cooling system of claim 3, wherein the control module includes control logic that adjusts the cooling air supplied to the forward turbine rotor wheel space based on emissions requirements.   The turbine cooling system of claim 3, comprising control logic that regulates the cooling air supplied to the forward turbine rotor wheel space to provide compressor surge protection for the compressor.   The apparatus further comprises a high pressure packing seal (HPPS), wherein a portion of the cooling air from the front turbine rotor wheel space leaks through the HPPS to generate a HPPS leakage flow that flows to the front turbine rotor wheel space. The turbine cooling system according to claim 1.   The turbine cooling system according to claim 1, wherein the metering device is one of a valve, a solenoid, and a pintle valve. In a turbine cooling system for a turbine,
A compressor for supplying cooling air;
A front turbine rotor wheel space cooled by the cooling air supplied from the compressor;
A high pressure packing seal (HPPS) bypass cavity that is in fluid communication with a portion of the cooling air from the compressor and that is in fluid communication with the cooling air and that is supplied to the front turbine rotor wheel space;
Operatively communicating with the front turbine rotor wheel space and the HPP bypass cavity, the cooling air supplied from the HPPS bypass cavity to the front turbine rotor wheel space based on at least one operating condition of the turbine A weighing device to be adjusted;
A control module that includes control logic that transmits control signals to the metering device to regulate the cooling air supplied to the forward turbine rotor wheel space based on at least one operating condition of the turbine;
A turbine cooling system comprising:   The turbine of claim 11, wherein the control module includes control logic that transmits a control signal to the metering device to adjust the cooling air supplied to the front turbine rotor wheel space based on ambient temperature. Cooling system.   The turbine cooling system of claim 11, wherein the control module includes control logic that adjusts the cooling air supplied to the forward turbine rotor wheel space based on a bulk metal temperature of a plurality of turbine blades.   The turbine cooling system of claim 11, wherein the control module includes control logic that adjusts the cooling air supplied to the front turbine rotor wheel space based on an air temperature in the front turbine rotor wheel space.   The turbine cooling system of claim 11, wherein the control module includes control logic that adjusts the cooling air supplied to the forward turbine rotor wheel space based on emissions requirements.   The turbine cooling system of claim 11, comprising control logic that regulates the cooling air supplied to the forward turbine rotor wheel space to provide compressor surge protection for the compressor.   The apparatus further comprises a high pressure packing seal (HPPS), wherein a portion of the cooling air from the front turbine rotor wheel space leaks through the HPPS to generate a HPPS leakage flow that flows to the front turbine rotor wheel space. The turbine cooling system according to claim 11.   The turbine cooling system according to claim 11, wherein the metering device is one of a valve, a solenoid, and a pintle valve. In a turbine cooling system for a turbine,
A compressor for supplying cooling air;
A front turbine rotor wheel space cooled by the cooling air supplied from the compressor;
A high pressure packing seal (HPPS) bypass cavity that is in fluid communication with a portion of the cooling air from the compressor and that is in fluid communication with the cooling air and that is supplied to the front turbine rotor wheel space;
Operatively communicating with the front turbine rotor wheel space and the HPP bypass cavity, the cooling air supplied from the HPPS bypass cavity to the front turbine rotor wheel space based on at least one operating condition of the turbine A weighing device to be adjusted;
A control module that includes control logic that transmits control signals to the metering device to adjust the cooling air supplied to the front turbine rotor wheel space based on at least one operating condition of the turbine cooling system;
And the control module includes control logic that transmits a control signal to the metering device to increase the amount of cooling air to the front turbine rotor wheel space.   The at least one operating condition is at least one of an environmental temperature, a total backflow margin of the turbine, a bulk metal temperature of a plurality of turbine blades, a temperature of a forward turbine rotor wheel space, a turbine emission requirement, and a compressor discharge pressure. The turbine cooling system of claim 19, wherein