JP2012031727A - Gas turbine and method for cooling gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine capable of cooling a casing with a small extraction amount of a compressor and to provide a method for cooling the gas turbine.SOLUTION: There is provided the gas turbine including a casing cooling structure 25 for cooling a casing and a cooling medium supply system 120 for supplying bleed air from the compressor 102 to the casing cooling structure. A flow rate amplifying means 116 for increasing a flow rate of a cooling medium is arranged in the cooling medium supply system 120 to suck an additional refrigerant by the bleed air and to supply the refrigerant to the casing cooling structure.

Description

  The present invention relates to a gas turbine and a gas turbine cooling method.

  The gas turbine has a configuration in which a rotor (rotary body) is included in a casing (stationary body). A turbine rotor blade is provided on the outer periphery of the rotor, and a gap exists between the tip (outermost periphery side) of the turbine rotor blade and the casing. When the high-temperature and high-pressure mainstream gas passes through this portion, leakage loss occurs and the performance deteriorates. Therefore, in order to improve the performance of the turbine, the gap between the turbine rotor blade and the shroud is preferably small.

  On the other hand, if the gap between the blade tip and the casing is too small, the blade tip and the shroud come into contact with each other, causing destruction. This gap changes during the operation of the gas turbine due to the thermal expansion and centrifugal elongation of the rotor and casing, etc. Therefore, the gap should be determined when assembling (starting) the casing so that contact damage does not occur under all operating conditions. ing.

  Generally, in industrial gas turbines, this minimum gap appears during startup. This is because the casing is less likely to warm than the rotor due to factors such as a difference in heat capacity. If the gap is minimized during non-steady operation, the gap must be designed so that contact does not occur during non-steady operation, and the gap during rated operation is larger than during startup, which is an undesirable excessive gap. It will drive at.

  In order to avoid this undesirably excessive gap, some gas turbines control the gap by suppressing the thermal expansion of the casing by cooling the casing by using compressor bleed air, air of a separate blower, etc. .

  For example, Patent Document 1 discloses a technique for cooling a casing with supply air from a blower, and Patent Document 2 discloses a technique for cooling a casing with compressor bleed air.

JP 2008-196490 A Japanese Patent Laid-Open No. 10-8911

  The hot part of the gas turbine is typically cooled by bleed air from the compressor. Here, when a separate device such as a blower is used, the number of devices of the gas turbine system increases and the reliability of the system decreases. In addition, the cost of the gas turbine system increases due to the increase in the number of devices. Therefore, it is desirable to avoid using separate devices as much as possible.

  On the other hand, when compressor bleed air is used for cooling the casing, the bleed air temperature is generally higher than the supply air temperature by the blower, so the same cooling performance as when using the blower supply air is used. In order to obtain it, a higher heat transfer rate, that is, a cooling air flow rate is required, so that the consumption of cooling air is equal to or higher than the blower. Since power is required to supply the cooling air, the efficiency of the gas turbine system is reduced by an increase in the cooling air supply power compared to the case where a blower is used.

  The present invention has been made in view of the above, and an object of the present invention is to provide a gas turbine that has high reliability and suppresses the amount of compressor extraction used for cooling the casing.

  In a gas turbine comprising a casing cooling structure for cooling a casing and a cooling medium supply system for supplying extracted air of a compressor as a cooling medium to the casing cooling structure, an additional refrigerant is supplied to the cooling medium supply system by the extracted air. A flow rate amplifying means for increasing the flow rate of the cooling medium that is sucked and supplied to the casing cooling structure is provided.

  According to the present invention, it is possible to provide a highly efficient gas turbine having high reliability and capable of cooling a casing with a small amount of compressor bleed.

The fragmentary sectional view of the gas turbine which is one Example of the present invention. 1 is a conceptual diagram of an embodiment of a gas turbine to which the present invention is applied. The fragmentary sectional view of the gas turbine to which the present invention is applied. The characteristic figure of the rotor blade tip clearance gap of the gas turbine of a comparative example. The characteristic view of the rotor blade tip gap of the gas turbine which is one Example of this invention. The fragmentary sectional view of the gas turbine which is one Example of the present invention. The characteristic view of the rotor blade tip gap of the gas turbine which is one Example of this invention. The fragmentary sectional view of the gas turbine which is one Example of the present invention. The fragmentary sectional view of the gas turbine which is one Example of the present invention.

  In the invention described in Patent Document 1, an impingement manifold is provided on the outer surface of the casing to cool the casing by impingement. This cooling air is guided from a separate blower. In general, the reliability of the system decreases as the number of devices increases. For example, when a blower such as an electrically driven blower is added, the risk of failure due to factors unrelated to the gas turbine main body such as a blower drive power supply failure or a blower main body failure increases. In a system that requires high reliability, it is desirable to avoid increasing the number of separate devices as much as possible.

  In the invention described in Patent Document 2, the casing cooling air cools the casing with the air extracted from the compressor.

  The air extracted from the compressor is guided to the turbine side through an extraction pipe provided outside the gas turbine as a cooling medium for the gas turbine high-temperature components. Since an increase in the amount of extracted piping leads to an increase in cost, for example, the number of extraction stages is limited to a few stages such as an intermediate stage and a subsequent stage of the compressor, and the number of extraction stages is generally smaller than the number of turbine stages to be cooled. Since the extraction stage is limited, normally, air having a pressure higher than that required for circulation of an appropriate amount of air is extracted. Especially in the case of casing cooling, there are those that release the air after casing cooling to the low pressure part such as the atmosphere or exhaust, and in such a case, the pressure of the extraction air is higher than the pressure necessary for the circulation of an appropriate amount of air. It will be a thing. Since the temperature of the air rises when the pressure increases due to compression, the temperature of the extracted air becomes higher than the temperature of the air supplied by a blower having a low blowing pressure. Therefore, when it is going to obtain the same cooling performance as the supply air by a blower, compared with the case where a blower is used, the amount of cooling air must be increased and a heat transfer rate must be made high.

  Furthermore, since power is required to supply cooling air, when the amount of compressor bleed air increases due to the use of cooling air, part of the performance improvement due to gap control is offset by this increase in power. For this reason, it is desirable that the casing can be cooled with a compressor bleed amount as small as possible.

  Hereinafter, according to the present invention described with reference to embodiments, it is possible to provide a high-efficiency gas turbine having high reliability and capable of cooling the casing with a small amount of compressor bleed.

First, the configuration of a gas turbine to which the present invention is applied will be described with reference to FIG.
FIG. 2 shows a system flow diagram of a gas turbine as a comparative example of the present embodiment.

  The gas turbine 101 mainly includes a compressor 102, a combustor 103, and a turbine 104. The compressor 102 compresses the atmospheric air 111 to generate compressed air 106, and sends the generated compressed air 106 to the combustor 103. The combustor 103 generates a combustion gas 107 by mixing and burning the compressed air 106 generated by the compressor 102 and fuel, and discharges the combustion gas 107 to the turbine 104.

  The turbine 104 generates a rotational force on the turbine shaft 105 by the combustion gas 107 discharged from the combustor 103 and having the energy of compressed air increased. The device 109 connected to the gas turbine 101 is driven by the rotational force of the turbine shaft 105. After the energy is recovered by the turbine 104, the combustion gas is discharged from the turbine 104 through the exhaust diffuser 113 as exhaust 112.

  A part of the air compressed by the compressor 102 is extracted as turbine cooling air 110 and supplied to the turbine 104 and the exhaust diffuser 113 without passing through the combustor 103.

  In addition, the casing cooling air 115 flows from the cooling air supply source 119 such as a blower such as a blower or the like to the casing 114 portion from the cooling air supply source 119 through the casing cooling air supply pipe 120 to cool the casing 114. The flow rate of the casing cooling air 115 is adjusted by a ventilation amount adjustment structure such as a power adjustment mechanism provided in the cooling air supply source 119 or a valve 123 provided in the casing cooling air supply pipe 120.

  FIG. 3 is a partial sectional view of a general gas turbine to which the present invention is applied.

  1 is a first stage stationary blade, 2 is a first stage stationary blade, 3 is a second stage stationary blade, 4 is a second stage stationary blade, 5 is a third stage stationary blade, 6 is a third stage stationary blade, and an arrow 8 is in the turbine. The flow direction of the combustion gas 107 is shown.

  The first stage blade 2 is connected to the outer periphery of the first stage wheel 9, and the second stage wheel 10 to which the second stage blade 4 is connected and the third stage to which the third stage blade 6 is connected. A turbine shaft 105 is configured by stacking with a wheel 11, a compressor rotor 12 connected to the compressor 102, and a spacer 13 together with a stacking bolt. The turbine shaft 105 recovers the energy of the combustion gas 107 discharged from the combustor 103 by the first stage blade 2, the second stage blade 4, and the third stage blade 6, and the compressor 102 and the turbine shaft end. A device 109 such as a generator connected to the unit is driven.

  The turbine shaft 105 is included in the casing 114. The turbine casing 114 is connected with a first stage stationary blade 1, a second stage stationary blade 3, a third stage stationary blade 5, a first stage shroud 14, a second stage shroud 15, and a third stage shroud 16 on the inner peripheral side of the casing. A diaphragm 24 is connected to the inner peripheral side of the second stage stationary blade 3 and the third stage stationary blade 5.

  There are gaps between the first stage blade 2 and the first stage shroud 14, the second stage blade 4 and the second stage shroud 15, the third stage blade 6 and the third stage shroud 16, and the spacer 13 and the diaphragm 24. The gap is an interface between the stationary body and the rotating body.

  This gap varies depending on the operating condition of the gas turbine. FIG. 4 shows the change trend of the gap. First, immediately after startup, the turbine shaft 105 increases in rotational speed, extends in the radial direction due to centrifugal force, and the gap decreases. Thereafter, the turbine shaft 105, the shrouds 14, 15, 16, and the casing 114 are thermally expanded due to the temperature rise of the mainstream gas. The turbine shaft 105 expands radially outward to expand the gap, and the shrouds 14, 15, 16 expand radially inward to reduce the gap. The casing 114 expands radially outward and expands the gap.

  In general, since the temperature of the turbine shaft 105 and the shrouds 14, 15, and 16 are more likely to rise than those of the casing 114, the turbine shaft 105 and the shrouds 14, 15, and 16 exhibit a minimum clearance before the turbine is thermally set, specifically near the time when the rated load is reached. . For this reason, the gap during steady operation is larger than the minimum gap.

  In order to suppress the gap expansion during the steady operation, a casing cooling device 25 for cooling the casing 114 from the outside or the inside is installed. Due to the cooling of the casing, the temperature of the casing 114 in the steady state decreases, so the temperature difference between the turbine shaft 105 and the casing 114 in the process from start to steady state decreases, and the difference between the minimum gap and the gap in the steady state is small. Become. As a result, the gap in the steady state can be kept small compared to the case where the casing is not cooled. The casing cooling device 25 is installed in an annular shape in accordance with the shape of the casing 114, and has an integral structure or a structure divided in the circumferential direction and the axial direction. A casing cooling air supply pipe 120 having a valve 123 for adjusting the amount of cooling air is connected to the casing cooling device 25, and a cooling air ejection hole is disposed in the casing cooling device 25. The casing cooling air 115 is guided to the casing cooling device 25 through the casing cooling air supply pipe 120, and the casing cooling air 115 is ejected from the cooling air ejection holes to cool the casing by collision. The ejected casing cooling air 115 is released into the atmosphere as it is or is collected and discharged to a low pressure part such as the inside of the exhaust diffuser 113.

  The constant gap is determined by the amount of thermal expansion of the casing 114, that is, the temperature of the casing 114. In order to obtain a target steady-state gap, the temperature and flow rate of the casing cooling air 115 are adjusted, and the amount of heat exchange between the casing 114 and the casing cooling air 115 is controlled, so that the casing temperature is the target steady time. The temperature may correspond to the gap.

Example 1
A gas turbine according to a first embodiment will be described with reference to FIG. FIG. 1 is a system flow diagram of this embodiment and corresponds to the system flow diagram of the comparative example of FIG.

In the present embodiment, an ejector 116 (cooling medium flow rate amplifying means) is provided in the casing cooling air supply pipe 120 with respect to the configuration of FIG.
The casing cooling air supply pipe 120 supplies the bleed air from the compressor 102. Other structures are the same as those in FIG. Compressor bleed air, which is a cooling medium, is mixed with a large amount of ambient gas 117 (additional refrigerant) sucked by the ejector 116 to form casing cooling air 115 having a low pressure and a large flow rate, and is used for casing cooling. The air after the casing is cooled is discharged into the enclosure 118 at approximately atmospheric pressure. The ejector 116 is connected to an additional refrigerant system that supplies ambient air 117 sucked by the ejector.

  The ejector 116 is a device that draws in the ambient gas 117 using the energy of a small amount of high-pressure air flowing from the upstream side, and creates a low-pressure, large-flow-rate air on the downstream side. Moreover, since the shape and principle are simple and no external power is required, the failure rate is low and the reliability is high. As such an ejector 116, a known one can be used, and it is desirable to use one that can suck a lot of air.

  The extraction stage of the compressor 102 has three stages, ie, the front side, the middle part, and the rear side of the compressor, and the casing cooling air supply pipe 120 is connected to the front extraction stage.

  Here, the number of extraction stages is three because when the number of extraction stages is increased, the cost is increased due to an increase in the number of piping and the like, which is a result of a trade-off between performance and cost. Due to the restriction on the number of extraction stages, the pressure of the air extracted from the front extraction stage is higher than the minimum pressure required for cooling the casing. If the pressure is excessively high, an excessive amount of cooling air flows, and an appropriate gap cannot be obtained. Conventionally, pressure loss is caused by an orifice, a valve, or the like, and the amount of cooling air is adjusted. However, it is wasteful and inefficient to cause a pressure loss only for flow adjustment. In the present embodiment, this high pressure is used to cause the ejector 116 to suck and mix the ambient gas 117, and the amount of cooling air on the rear side of the ejector is increased compared to the amount of extracted air. As a result, it is possible to obtain the amount of cooling air necessary to achieve the target steady-time gap while suppressing the amount of extracted air used that causes the performance degradation of the gas turbine.

  Furthermore, since the ambient gas 117 is cooler than the temperature of the bleed air, the temperature of the casing cooling air 115 is reduced by mixing with the ambient gas 117. The amount of cooling air required to obtain the target steady-state gap can be reduced by the amount of the temperature decrease.

  FIG. 5 shows the gas turbine gap characteristics when the casing is cooled.

  During the start of the gas turbine, the gap is reduced by casing cooling, so that the amount of change in the gap from the start to the minimum gap becomes larger than when the casing is not cooled. Accordingly, by expanding the assembling gap, the minimum gap can be made equal to the case where casing cooling is not performed, and the performance can be improved without degrading the reliability of the gas turbine.

  Here, during the start-up, the pressure of the compressor bleed air is low, and the flow rate of the bleed air is also small. Under this condition, the flow rate amplification effect of the ejector 116 is also small, so the flow rate of the casing cooling air 115 is small. Therefore, the effect of reducing the gap at the start-up due to the casing cooling during the start-up is smaller than the effect of reducing the gap in the steady state, and the temperature of the casing 114 is lower in the steady state. The temperature difference between the turbine shaft 105 and the casing 114 is reduced, and the difference between the minimum gap and the gap in the steady state is reduced. As a result, the gap in the steady state can be kept small compared to the case where the casing is not cooled.

  Further, when the casing cooling effect during the start-up is so small as to be negligible, the present embodiment can be applied only by repairing the bleed piping portion without changing the assembling gap. In such a case, the present invention is applied to a gas turbine that is already in operation, and the efficiency of the gas turbine can be improved at a low cost.

  Compared with the comparative example shown in FIG. 2, in this embodiment, the valve 123 can be eliminated and the number of equipment can be reduced, so that the reliability of the gas turbine can be improved and the cost can be reduced.

  Further, since the flow rate of the casing cooling air supply pipe 120 on the downstream side of the ejector 116 is larger than that in front of the ejector 116 and the pressure is further reduced, the flow rate of the casing cooling air 115 is increased. In order to suppress an increase in pressure loss due to this effect, the ejector 116 is desirably provided in the vicinity of the casing cooling portion.

  In addition, the interior of the enclosure 118 that houses the gas turbine has a temperature higher than that of the atmosphere due to heat radiation from the gas turbine. Further, the air inside the enclosure 118 has a temperature distribution due to the convection of air by the ventilation fan. In order to lower the temperature of the cooling air, it is desirable to suck the air at the lowest possible temperature with the ejector 116.

  In the present embodiment, the air after cooling the casing is discharged to a portion at almost atmospheric pressure, but it may be used for cooling a further coolable portion such as an exhaust diffuser.

  Further, it may be combined with a technique for reducing the temperature of the casing cooling air 115 such as installing an intercooler on the upstream side of the ejector 116 of the casing cooling air supply pipe 120.

  In the present embodiment, an example in which the impingement cooling structure is provided on the outer peripheral side of the casing 114 as the casing cooling device 25 is shown, but it may be combined with other casing cooling methods.

(Example 2)
A gas turbine according to the second embodiment will be described with reference to FIG. FIG. 6 is a system flow diagram of the gas turbine. In the configuration of the first embodiment, a valve 123 is installed in the casing cooling air supply pipe 120. Other structures are the same as those in the first embodiment. 6 shows a configuration in which air inside the enclosure 118 is used as an additional refrigerant for the cooling medium, but air outside the enclosure 118 or another cooling medium may be used.

  FIG. 7A shows the gas turbine gap characteristics and the operation method of the valve 123 when the casing is cooled in this embodiment. In the first embodiment, the flow rate control of the casing cooling air 115 is not performed, but in this embodiment, the valve 123 is opened after the minimum gap is reached, and the casing cooling is started. By starting the casing cooling after reaching the minimum gap, the gap change amount from the start to the minimum gap can be made the same as when the casing is not cooled, so the assembly gap is changed. The performance can be improved without impairing the reliability of the gas turbine.

Further, the flow rate of the casing cooling air 115 can be adjusted using the valve 123 such that the casing temperature is measured and the temperature becomes a temperature corresponding to the target steady-state gap.
The temperature inside the enclosure 118 and the temperature of the extraction air vary due to factors such as fluctuations in the outside air temperature. Since the gap also changes when these temperature conditions change, in Example 1, the target steady-state gap is set at the severest temperature condition where the gap is the smallest. Since it becomes more than a target gap | clearance other than the most severe temperature conditions, the performance of a gas turbine will fall in other than the most severe temperature conditions. In the present embodiment, the flow rate of the casing cooling air 115 can be adjusted each time according to the temperature fluctuation by the valve 123, so that the gap can always be set as a target steady-state gap.

  In this embodiment, the gas turbine output is monitored, the arrival of the minimum gap is detected from the relationship between the output and the gap evaluated in advance, and the timing for starting the casing cooling is determined. In addition to this method, the casing cooling may be started by detecting that the minimum gap timing has passed from various information such as the casing temperature, the measured value of the blade tip clearance, and the elapsed time from the start of startup.

  Further, since the temperature rise of the casing 114 is slower than the temperature rise of the working fluid of the gas turbine and the extraction air, the temperature of the compressor extraction air becomes higher than the temperature of the casing 114 during the start-up, and the extraction is performed after reaching the minimum gap. The temperature of the air may be lower than the temperature of the casing 114. FIG. 7B shows a desirable operation method of the valve 123 in such a case and the gas turbine gap characteristics at that time.

  The casing cooling device 25 heats the casing 114 by opening the valve 123 before reaching the minimum gap and when the temperature of the casing cooling air is higher than the temperature of the casing 114. On the other hand, before reaching the minimum gap and when the temperature of the casing cooling air is lower than the temperature of the casing 114, the valve 123 is closed, and after reaching the minimum gap, the valve 123 is put into a state. Gives the effect of cooling. Before reaching the rating, the casing 114 is heated and expands, so that the gap at the time of cooling the casing is larger than that without the casing cooling, and the minimum gap is also increased. After reaching the rating, the casing 114 is cooled and contracts, so that the gap during the casing cooling is reduced as compared with the case without the casing cooling. Thus, the difference between the minimum gap and the steady-state gap can be reduced.

  If the initial gap is re-examined as much as the minimum gap is increased and the initial gap is reduced to the same minimum gap as when the casing is not cooled, the steady state is achieved with the same amount of cooling air as when the heating effect is not considered. The gap at can be set smaller. Further, when the steady-time gap is made equal to the case where the heating effect is not taken into consideration, the casing cooling air amount can be reduced.

  Moreover, it is desirable that the method for improving the efficiency of the gas turbine, which is an object of the present invention, can be applied not only to a newly installed gas turbine but also to many devices such as an existing gas turbine. The invention according to this embodiment can be carried out only by refurbishing the bleed piping portion of a conventional gas turbine. By applying the present invention to a gas turbine that is already in operation, the efficiency of the gas turbine can be improved at a low cost.

(Example 3)
A gas turbine according to the third embodiment will be described with reference to FIG. FIG. 8 is a system flow diagram of the gas turbine. In the configuration of the first embodiment, air sucked by the ejector 116 is supplied from the outside of the enclosure 118. Other structures are the same as those in the first embodiment. In addition, although the example which installed the valve 123 in the casing cooling air supply piping 120 is shown in FIG. 8, installation of the valve 123 can be selected suitably.

In the first embodiment, the ejector 116 sucks air inside the enclosure 118.
The air temperature inside the enclosure 118 is higher than the air temperature outside the enclosure 118 due to heat radiation from the gas turbine. Therefore, the temperature of the casing cooling air 115 can be lowered by supplying the air sucked by the ejector 116 from the outside of the enclosure 118. As the temperature decreases, the amount of cooling air required to achieve the target steady-state gap is reduced, and the amount of extracted air can be reduced.

  The enclosure 118 is ventilated by a ventilation fan so that the internal air temperature does not become too high. According to the present embodiment, the amount of air flowing from the outside of the enclosure 118 to the inside by the suction of the ejector 116 increases, so the air temperature inside the enclosure 118 decreases. Due to this effect, the amount of natural heat radiation of the casing is increased, so that it is possible to reduce the amount of cooling air necessary to obtain the target steady-state gap.

  Furthermore, although various gas turbine auxiliary machines are installed inside the enclosure 118, the reliability of these auxiliary machines can be improved by lowering the ambient temperature.

Example 4
A gas turbine according to the fourth embodiment will be described with reference to FIG. FIG. 9 is a system flow diagram of the gas turbine. Compared with the configurations of the first and second embodiments, an additional refrigerant such as water, high-humidity air, or steam is added to the refrigerant 121 sucked by the ejector 116 by the refrigerant mixing device 122. It is mixed. Other structures are the same as those in the first and second embodiments. Although FIG. 9 illustrates a configuration in which air inside the enclosure 118 is used as an additional refrigerant for the cooling medium, air outside the enclosure 118 or another cooling medium may be used. Moreover, although the example which installed the valve 123 in the casing cooling air supply piping 120 is shown in FIG. 9, installation of the valve 123 can be selected suitably.

  The additional refrigerant is a gas or a liquid having a larger thermal conductivity and heat capacity than air. Since the refrigerant having such characteristics has high cooling performance, it is possible to reduce the amount of cooling air necessary to obtain the target steady-state gap.

  As the coolant 121, for example, air containing fine droplets generated by a spray nozzle or the like may be used. When air containing fine droplets mixes with the bleed air in the ejector 116, the droplets are vaporized and take latent heat from the casing cooling air 115. As a result, the temperature of the casing cooling air 115 decreases. Furthermore, by including moisture, the heat conductivity of the casing cooling air 115 increases, and the heat transfer coefficient of casing cooling improves.

  Further, steam or air containing steam may be used as the refrigerant 121. When the casing cooling air contains moisture, the thermal conductivity of the cooling air is increased and the cooling performance is improved. It is desirable to use a method that does not consume new energy for supplying steam, such as using low-temperature and low-pressure steam that is discarded from other facilities.

  Further, water may be used as the refrigerant 121. The water sucked by the ejector 116 is subjected to a shearing force and atomized in the ejector 116 due to a speed difference from the extracted air whose flow rate is increased. The atomized water droplets are vaporized by mixing with the extraction air and take away latent heat from the extraction air. As a result, the temperature of the casing cooling air 115 is lowered, and the cooling performance is improved due to the effect of increasing the heat transfer coefficient by containing moisture. In addition, when the pressure of the bleed air is sufficiently high, two or more ejectors 116 that suck water into the casing cooling air supply pipe 120 and two or more ejectors 116 that suck the ambient gas 117 may be provided in series.

DESCRIPTION OF SYMBOLS 1 First-stage stationary blade 2 First-stage stationary blade 3 Second-stage stationary blade 4 Second-stage stationary blade 5 Third-stage stationary blade 6 Third-stage stationary blade 8 Flow direction of main flow gas 9 First-stage wheel 10 Second-stage wheel 11 Third-stage Wheel 12 Compressor rotor 13 Spacer 14 First stage shroud 15 Second stage shroud 16 Third stage shroud 24 Diaphragm 25 Casing cooling device 101 Gas turbine 102 Compressor 103 Combustor 104 Turbine shaft 105 Compressed air 107 Combustion gas 109 Equipment 110 Turbine cooling air 111 Atmospheric air 112 Exhaust 113 Exhaust diffuser 114 Casing 115 Casing cooling air 116 Ejector 117 Ambient gas 118 Enclosure 119 Cooling air supply source 120 Casing cooling air supply piping 121 Refrigerant 122 Refrigerant mixing device 123 Valve

Claims (15)

A compressor for generating compressed air;
A combustor that generates combustion gas by mixing and burning compressed air and fuel generated by the compressor;
A turbine that is rotationally driven by the combustion gas generated in the combustor;
A turbine casing containing the turbine;
A casing cooling structure for cooling the turbine casing;
In a gas turbine comprising a cooling medium supply system for supplying extracted air of the compressor as a cooling medium to the casing cooling structure,
A gas turbine characterized in that the cooling medium supply system is provided with a flow rate amplifying means for sucking additional refrigerant with the extracted air and increasing the flow rate of the cooling medium supplied to the casing cooling structure. The gas turbine according to claim 1, wherein
The flow rate amplifying means includes an inlet for the additional refrigerant,
At least one of the suction ports is installed in an enclosure containing the gas turbine. The gas turbine according to claim 1, wherein
The flow rate amplifying means includes an inlet for the additional refrigerant,
At least one of the suction ports is installed outside an enclosure containing the gas turbine. The gas turbine according to claim 1, wherein
The flow rate amplifying means includes an additional refrigerant system through which the additional refrigerant flows;
A gas turbine characterized in that the additional refrigerant system includes droplet spraying means for generating fine droplets. The gas turbine according to claim 1, wherein
The flow rate amplifying means includes an inlet for the additional refrigerant,
A gas turbine characterized in that the suction port is connected to means for supplying steam. The gas turbine according to claim 1, wherein
A gas turbine comprising a flow rate changing means for changing a flow rate of the refrigerant in the cooling medium supply system. The gas turbine according to claim 1, wherein
A gap detecting means for detecting that a moving blade tip gap serving as a rotating interface between the turbine and the casing has become a minimum value at the time of starting, and outputting a detection signal;
A gas turbine comprising flow rate changing means for increasing a flow rate of a cooling medium supplied to the casing cooling structure by an output of the detection signal. A compressor for generating compressed air;
A combustor that generates combustion gas by mixing and burning compressed air and fuel generated by the compressor;
High-temperature components heated by the combustion gas generated in the combustor;
A cooling structure for cooling the high-temperature component;
A gas turbine cooling method comprising a cooling medium supply system for supplying extracted air of the compressor as a cooling medium to the cooling structure,
A cooling method for a gas turbine, comprising: sucking an additional refrigerant into the cooling medium supply system with the extracted air and increasing a flow rate of the cooling medium supplied to the cooling structure. A compressor for generating compressed air;
A combustor that generates combustion gas by mixing and burning compressed air and fuel generated by the compressor;
A turbine that is rotationally driven by the combustion gas generated in the combustor;
A turbine casing containing the turbine;
A casing cooling structure for cooling the turbine casing;
A cooling method for a gas turbine comprising a cooling medium supply system for supplying extracted air of the compressor to the casing cooling structure as a cooling medium,
A method for cooling a gas turbine, comprising: sucking additional refrigerant into the cooling medium supply system with the extracted air and increasing a flow rate of the cooling medium supplied to the gas turbine cooling structure. The method for cooling a gas turbine according to claim 9,
The method for cooling a gas turbine, wherein the additional refrigerant is air in the enclosure. The method for cooling a gas turbine according to claim 9,
The method for cooling a gas turbine, wherein the additional refrigerant is air outside the enclosure. The method for cooling a gas turbine according to claim 9,
The method for cooling a gas turbine, wherein the additional refrigerant includes liquid phase or vapor phase water. The method for cooling a gas turbine according to any one of claims 9 to 12,
A method for cooling a gas turbine, comprising: changing a flow rate of a cooling medium supplied to the casing cooling structure during operation of the gas turbine. The method for cooling a gas turbine according to any one of claims 9 to 12,
A method for cooling a gas turbine, comprising: increasing a flow rate of the cooling medium after detecting that a moving blade tip gap serving as a rotational interface between the turbine and the turbine casing reaches a minimum value at startup. The method of cooling a gas turbine according to claim 9 to 14,
The compressor includes at least one extraction stage for extracting the extraction air,
In the extraction stage, immediately after the gas turbine is started, the temperature of the turbine casing is lower than the temperature of the extraction air, and during the steady operation of the gas turbine, the temperature of the turbine casing is higher than the temperature of the extraction air. A gas turbine cooling method characterized by being selected as described above.

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