Patent Grant
11913476
The present invention relates to a compressor system.
Priority is claimed on Japanese Patent Application No. 2019-059225, filed Mar. 26, 2019, the content of which is incorporated herein by reference.
For example, it is known that, if an operation point is changed to increase a pressure ratio while keeping the number of revolutions constant in turbo compressors including axial compressors and centrifugal compressors, a phenomenon called turning stall or surging may occur in some cases. Particularly, surging is likely to lead to backflow of a working fluid inside a compressor and vibration of a rotor shaft in some cases. For this reason, there is an increasing demand for techniques which can prevent or minimize surging.
As an example of such a technique, the technique described in Patent Literature 1 is known. Patent Literature 1 discloses various detection devices including a static pressure sensor, a dynamic pressure sensor, and a flow velocity sensor and a technique for perceiving changes that are indications of surging through frequency-processing a detection value using such detection devices.
[Patent Literature 1]
However, in the device described in Patent Literature 1, detection values using each of the detection devices may be included in noise (a fluctuation component) unless surging has progressed to some extent in some cases. Thus, it may not be possible to accurately detect an indication of surging in some cases.
The present invention was made to solve the above problems, and an object of the present invention is to provide a compressor system capable of detecting the occurrence of surging with higher accuracy and minimizing surging.
A compressor system according to an aspect of the present invention includes: a compressor having: an upstream region into which a working fluid flows, a downstream region that communicates with the upstream region and in which a pressure of the working fluid is greater than that in the upstream region, inlet guide vanes that are provided further upstream than the upstream region and are capable of altering a flow rate of the working fluid flowing into the upstream region, and an extraction part that is provided to a portion between the upstream region and the downstream region and is capable of extracting at least a portion of the working fluid; detection devices, at least one of which is provided in each of the upstream region and the downstream region, for detecting a physical quantity of the working fluid; and a control device for adjusting, on the basis of changes in the physical quantity detected by the detection devices, any one of an opening degree of the inlet guide vanes and an amount extracted by the extraction part.
According to the above constitution, at least one of the detection devices is provided in the upstream region and the downstream region of the compressor. The detection device detects a physical quantity of the working fluid. The control device detects an abnormality occurring in the flow of the working fluid on the basis of the changes in the physical quantity. The control device adjusts either the opening degree of the inlet guide vane or the extraction amount. Thus, it is possible to eliminate an abnormality occurring in the flow of the working fluid.
In the compressor system, each of the detection devices may include: a pair of temperature detection units that are arranged in a flow direction of the working fluid; and a heating unit that is disposed between the pair of temperature detection units and heats the working fluid, wherein the physical quantities may include a flow direction and a flow velocity of the working fluid based on a temperature difference of the working fluid detected by the pair of temperature detection units.
According to the above constitution, the detection device has the pair of temperature detection units arranged in the flow direction and the heating unit provided between them. When the working fluid passes through the pair of temperature detection units in the flow direction, the working fluid is heated by the heating unit. Thus, a difference occurs in a temperature which is detected between a temperature detection unit located on the downstream side in the flow direction and a temperature detection unit located on the upstream side. Therefore, it is possible to detect that the working fluid is flowing to a side on which the temperature detection unit having a higher detected temperature is located. That is to say, it is possible to detect the flow direction of the working fluid. In addition, when an absolute value of the temperature difference detected by the pair of temperature detection units is detected, it is also possible to detect changes in the flow velocity of the working fluid. Thus, for example, when backflow (that is, a change in the flow direction) occurs in the flow of the working fluid inside the compressor or a decrease in the flow velocity that is an indication of backflow occurs, it is possible to immediately detect the backflow and the decrease in the flow velocity.
In the above compressor system, the temperature detection unit and the heating unit may be directed exposed to the working fluid.
According to the above constitution, it is possible to immediately detect changes in the physical quantity of the working fluid. Thus, this makes it possible to improve the responsiveness of the entire device.
In the above compressor system, the control device may adjust the opening degree of the inlet guide vanes so that the opening degree increases when the temperature difference changes so that the temperature difference decreases in the downstream region.
According to the above constitution, when the temperature difference between the pair of temperature detection units detected by the detection devices in the downstream region decreases, it can be determined that the flow velocity of the working fluid has decreased in the downstream region. When the flow velocity continues to decrease, this is eventually likely to lead to a change in the flow direction. That is to say, it can be said that the decrease in flow velocity is an indication of backflow. In this case, it can be determined that the flow rate of the working fluid in the downstream region of the compressor becomes excessive and the flow of the working fluid begins to come to a standstill (surging is occurring). Thus, the control device adjusts the opening degree of the inlet guide vane so that the opening degree increases. Therefore, the flow rate of the working fluid supplied to the downstream region is reduced. As a result, surging can be prevented before the development thereof.
In the above compressor system, the control device may adjust the extraction amount so that the extraction amount increases when the temperature difference changes in the upstream region so that the temperature difference decreases.
According to the above constitution, when the temperature difference between the pair of temperature detection units detected by the detection devices in the upstream region decreases, it can be determined that the flow velocity of the working fluid has decreased in the upstream region. When the flow velocity continues to decrease, this is likely to eventually lead to a change in the flow direction. That is to say, it can be said that the decrease in the flow velocity is an indication of backflow. In this case, it can be determined that the flow rate of the working fluid in the upstream region of the compressor becomes excessive and the flow of the working fluid begins to come to a standstill (surging is occurring). Thus, the control device adjusts the extraction amount so that the extraction amount increases. Therefore, the working fluid that has come to a standstill in the upstream region is extracted and the standstill in the flow is eliminated. As a result, surging can be prevented before the development thereof.
In the above compressor system, the compressor may include: a rotor shaft that is capable of rotating around an axis line; a plurality of rotor blade stages that are provided on the rotor shaft and arranged in a direction of the axis line; a casing that covers the rotor shaft and the rotor blade stages from an outer circumferential side; and a plurality of stator blade stages that are provided on an inner circumferential surface of the casing and arranged alternately with the plurality of rotor blade stages in the direction of the axis line, wherein the upstream region being a region further upstream than a rotor blade stage of the plurality of rotor blade stages that is a third stage from the furthest upstream side, and wherein the downstream region being a region further downstream than a rotor blade stage of the plurality of rotor blade stages that is a third stage from the furthest downstream side.
Here, in the compressor as described above, it is known that surging particularly easily occurs in the region further upstream than the third rotor blade stage from the furthest upstream side and the region further downstream than the third rotor blade stage from the furthest downstream side. According to the above constitution, since the regions are the upstream region and the downstream region, it is possible to promptly and accurately detect the occurrence of surging and an indication thereof.
In the above compressor system, each of the stator blade stages may extend in a radial direction with respect to the axis line and include a plurality of stator blades arranged in a circumferential direction and having a suction surface facing upstream and a pressure surface facing downstream, and the detection device may be provided on the suction surface.
Here, the separation and the backflow of the working fluid are particularly easily generated on the suction surface of the stator blade. According to the above constitution, since the detection device is provided on the suction surface, it is possible to promptly and accurately detect the separation and the backflow described above.
In the above compressor system, the compressor may include: a rotor shaft that is capable of rotating around an axis line; an impeller that is provided on the rotor shaft; and a casing that covers the impeller from an outer circumferential side and forms a flow path through which the working fluid flows on an upstream side and a downstream side of the impeller, wherein the upstream region being a region in the flow path further upstream than the impeller, and wherein the downstream region being a region in the flow path further downstream than the impeller.
Here, it is known that, in the compressor as described above, surging particularly easily occurs in a region further upstream than the impeller and a region further downstream than the impeller. According to the above constitution, since the regions are the upstream region and the downstream region, it is possible to promptly and accurately detect the occurrence of surging and an indication thereof.
In the above compressor system, the flow path may have a diffuser flow path provided on a downstream side of the impeller and configured to guide the working fluid from an inner side to an outer side in the radial direction with respect to the axis line and a return flow path provided further downstream of the diffuser flow path and configured to guide the working fluid from the outer side to the inner side in the radial direction, and the detection device may be provided in at least one of the diffuser flow path and the return flow path.
According to the above constitution, since the detection device is provided in at least one of the diffuser flow path and the return flow path, it is possible to finely and accurately detect the occurrence of surging and an indication thereof in the downstream region.
A compressor system according to an aspect of the present invention includes: a compressor having: an upstream region into which a working fluid flows, a downstream region that communicates with the upstream region and in which a pressure of the working fluid is greater than that in the upstream region, inlet guide vanes that are provided further upstream than the upstream region and are capable of altering a flow rate of the working fluid flowing into the upstream region, and an extraction part that is provided to a portion between the upstream region and the downstream region and is capable of extracting at least a portion of the working fluid; detection devices, at least one of which is provided in each of the upstream region and the downstream region, for detecting a physical quantity of the working fluid; and a control device for adjusting, on the basis of changes in the physical quantity detected by the detection devices, an opening degree of the inlet guide vanes and an amount extracted by the extraction part, wherein the compressor includes: a rotor shaft that is capable of rotating around an axis line; a plurality of rotor blade stages that are provided on the rotor shaft and arranged in a direction of the axis line; a casing that covers the rotor shaft and the rotor blade stages from an outer circumferential side; and a plurality of stator blade stages that are provided on an inner circumferential surface of the casing and arranged alternately with the plurality of rotor blade stages in the direction of the axis line, wherein the upstream region is a region further upstream than a rotor blade stage of the plurality of rotor blade stages that is a third stage from the furthest upstream side, wherein the downstream region is a region further downstream than a rotor blade stage of the plurality of rotor blade stages that is a third stage from the furthest downstream side, wherein each of the stator blade stages extends in a radial direction with respect to the axis line and includes a plurality of stator blades arranged in a circumferential direction and having a suction surface facing upstream and a pressure surface facing downstream, and wherein each of the detection devices is provided on the suction surface.
At least one of the detection devices is provided in each of the upstream region and the downstream region of the compressor. The detection device detects a physical quantity of the working fluid. The control device detects an abnormality occurring in the flow of the working fluid on the basis of the changes in the physical quantity. The control device adjusts either the opening degree of the inlet guide vane or the extraction amount. Thus, it is possible to eliminate the abnormality occurring in the flow of the working fluid. In addition, it is known that, in the compressor as described above, surging particularly easily occurs in the region further upstream than the third rotor blade stage from the furthest upstream side and the region further downstream than the third rotor blade stage from the furthest downstream side. According to the above constitution, since the regions are the upstream region and the downstream region, it is possible to promptly and accurately detect the occurrence of surging and an indication thereof. Here, the separation and the backflow of the working fluid are particularly easily generated on the suction surface of the stator blade. According to the above constitution, since the detection device is provided on the suction surface, it is possible to promptly and accurately detect the separation and the backflow described above.
In the above compressor system, the detection device may include: a pair of temperature detection units that are arranged in a flow direction of the working fluid; and a heating unit that is disposed between the pair of temperature detection units and heats the working fluid, wherein the physical quantity may include a temperature difference of the working fluid detected by the pair of temperature detection units, and wherein the control device may determine a speed at which each of the inlet guide vanes is closed on the basis of a magnitude of the physical quantity when a command for reducing a load of the compressor is issued.
Here, when a command for reducing a load of the compressor is issued, if the inlet guide vane is closed at an excessively high speed to reduce the inflow of the working fluid, there is a risk of there being an insufficient amount of working fluid compressed in the downstream region and backflow of the working fluid to the upstream side (surging occurring). On the other hand, when the inlet guide vane is closed at an excessively low speed, the temperature of the combustion gas decreases due to an excessive supply of the working fluid to the combustor provided on the downstream side. As a result, there is a risk of generating combustion vibration and increasing an amount of NOx which is emitted. According to the above constitution, the control determines the speed at which the inlet guide vane is closed on the basis of the temperature difference detected by the pair of temperature detection units, that is, the speed or the flow rate of the fluid. For this reason, it is possible to close the inlet guide vane at an appropriate speed while preventing the surge and the unstable combustion described above. As a result, it is possible to stably and quickly reduce a load on the compressor.
In the above compressor system, the control device may close the inlet guide vane at a relatively high speed when the physical quantity is greater than a predetermined threshold value and close the inlet guide vane at a relatively low speed when the physical quantity is smaller than the threshold value.
According to the above constitution, it is possible to determine an optimum speed at which the inlet guide vane is closed simply by evaluating the magnitude of the physical quantity on the basis of the predetermined threshold value. Thus, it is possible to quickly reduce the load on the compressor while minimizing the likelihood of surges and unstable combustion occurring.
In the above compressor system, the control device may determine to which numerical range of a plurality of predetermined numerical ranges the physical quantity belongs and close the inlet guide vane by selecting a predetermined speed to correspond to the numerical range to which the physical quantity belongs.
According to the above constitution, it is possible to close the inlet guide vane by selecting the speed determined to correspond to the numerical range to which the physical quantity belongs. That is to say, it is possible to finely determine the speed at which the inlet guide vane will be closed on the basis of the magnitude of the physical quantity. As a result, it is possible to more quickly reduce the load on the compressor while further minimizing the likelihood of surges and unstable combustion occurring.
In the above compressor system, the control device may determine a speed at which the inlet guide vane is closed with reference to a table in which a relationship between the physical quantity and an optimum speed at which the inlet guide vane is closed according to a value concerning the physical quantity is shown.
According to the above constitution, it is possible to close the inlet guide vane by selecting the speed in accordance with the table in which the relationship between the optimum speed at which the inlet guide vane is closed and the physical quantity is shown. That is to say, it is possible to more finely determine the speed at which the inlet guide vane is closed on the basis of the magnitude of the physical quantity. Thus, it is possible to more quickly reduce the load on the compressor while further minimizing the likelihood of surges and unstable combustion occurring.
A compressor system according to an aspect of the present invention includes: a compressor having: an upstream region into which a working fluid flows, a downstream region that communicates with the upstream region and in which a pressure of the working fluid is greater than that in the upstream region, and inlet guide vanes that are provided further upstream than the upstream region and are capable of altering a flow rate of the working fluid flowing into the upstream region; detection devices, at least one of which is provided in the downstream region, for detecting a physical quantity of the working fluid; and a control device for adjusting, on the basis of changes in the physical quantity detected by the detection devices, an opening degree of the inlet guide vanes, wherein each of the detection devices includes a pair of temperature detection units that are arranged in a flow direction of the working fluid; and wherein a heating unit that is disposed between the pair of temperature detection units and heats the working fluid, wherein the physical quantity includes a temperature difference of the working fluid detected by the pair of temperature detection units, and wherein when a command for reducing a load of the compressor is issued, the control device determines a speed at which each of the inlet guide vanes is closed on the basis of a magnitude of the physical quantity.
Here, when a command for reducing a load on the compressor is issued, if the inlet guide vane is closed at an excessively high speed to reduce the inflow of the working fluid, there is a risk of there being an insufficient amount of working fluid compressed in the downstream region and backflow of the working fluid to the upstream side (surging occurring). On the other hand, when the inlet guide vane is closed at an excessively low speed, the temperature of the combustion gas decreases due to an excessive supply of the working fluid to the combustor provided on the downstream side. As a result, there is a risk of generating combustion vibration and increasing an amount of NOx which is emitted. According to the above constitution, the control device determines the speed at which the inlet guide vane is closed on the basis of the temperature difference detected by the pair of temperature detection units, that is, the speed or the flow rate of the fluid. For this reason, it is possible to close the inlet guide vane at an appropriate speed while preventing the surge and the unstable combustion described above. As a result, it is possible to stably and quickly reduce a load on the compressor.
In the above compressor system, the control device may close the inlet guide vane at a relatively high speed when the physical quantity is greater than a predetermined threshold value and close the inlet guide vane at a relatively low speed when the physical quantity is smaller than the threshold value.
According to the above constitution, it is possible to determine the optimum speed at which the inlet guide vane is closed simply by evaluating the magnitude of the physical quantity on the basis of the predetermined threshold value. Thus, it is possible to quickly reduce the load on the compressor while reducing the likelihood of surges and unstable combustion occurring.
In the above compressor system, the control device may determine to which numerical range of a plurality of predetermined numerical ranges the physical quantity belongs and close the inlet guide vane by selecting a predetermined speed to correspond to the numerical range to which the physical quantity belongs.
According to the above constitution, it is possible to close the inlet guide vane by selecting the speed determined to correspond to the numerical range to which the physical quantity belongs. That is to say, it is possible to more finely determine the speed at which the inlet guide vane is closed on the basis of the magnitude of the physical quantity. As a result, it is possible to more quickly reduce the load on the compressor while further reducing the likelihood of surges and unstable combustion occurring.
In the compressor system, the control device may determine a speed at which the inlet guide vane is closed with reference to a table in which a relationship between the physical quantity and an optimum speed at which the inlet guide vane is closed according to a value concerning the physical quantity is shown.
According to the above constitution, it is possible to close the inlet guide vane by selecting the speed in accordance with the table in which the relationship between the optimum speed at which the inlet guide vane is closed and the physical quantity is shown. That is to say, it is possible to more finely determine the speed at which the inlet guide vane is closed on the basis of the magnitude of the physical quantity. Thus, it is possible to more quickly reduce the load on the compressor while further reducing the likelihood of surges and unstable combustion occurring.
According to the present invention, it is possible to provide a compressor system capable of detecting the occurrence of surging with higher accuracy and minimizing surging.
A first embodiment of the present invention will be described with reference to
The compressor system 1 includes a compressor 11, inlet guide vanes 11C, detection devices 21, a blow-off flow path L (an extraction part), a blow-off valve V, and a control device 90. The compressor 11 compresses air guided from one side (an upstream side) in a direction of an axis line O and supplies the compressed air to the combustor 2 provided on the other side (a downstream side). That is to say, the compressor 11 is an axial compressor. Although being described in detail later, the compressor 11 includes an upstream region 11A located on an upstream side in the direction of the axis line O and a downstream region 11B located on a downstream side. The pressure of the working fluid (air) in the downstream region 11B is greater than that in the upstream region 11A. External air is introduced into the upstream region 11A via the inlet guide vane 11C. The inlet guide vane 11C is provided to adjust an amount of air flowing through the upstream region 11A. Opening degree of the inlet guide vane 11C can be changed using an electrical signal transmitted from the control device 90 which will be described later.
In the upstream region 11A, at least one (a first detection device 21A) of the detection devices 21 which detect a physical quantity of air flowing through the upstream region 11A is provided. Similarly, in the downstream region 11B, at least one (a second detection device 21B) of the detection devices 21 which detect a physical quantity of air flowing through the downstream region 11B is provided.
Here, as shown in
Also, the downstream region 11B described above refers to a region further downstream than a rotor blade stage 42 of the plurality of rotor blade stages 42 that is a third stage from the furthest downstream side. That is to say, the second detection device 21B is provided on the inner circumferential surface of the casing 30 corresponding to a rotor blade stage 42 that is on the furthest downstream side (an outlet final rotor blade stage 42D) and a rotor blade stage 42 that is a second stage from the downstream side (an outlet rotor blade stage 42C). It is also possible to provide the second detection device 21B for an outlet final stator blade stage 41D adjacent to the outlet final rotor blade stage 42D and an outlet stator blade stage 41C adjacent to the outlet rotor blade stage 42C. Furthermore, it is also possible to provide the second detection device 21B on the inner circumferential surface of the casing 30 corresponding to a diffuser flow path stator blade stage 41E provided on a downstream side of the outlet final rotor blade stage 42D.
The detection device 21 detects, as physical quantities, changes in flow direction Df and flow velocity of air in the compressor 11. As shown in
As shown in
The control device 90 adjusts an opening degree of the inlet guide vane 11C and an opening degree of the blow-off valve V on the basis of the physical quantity detected by the detection device 21 described above. As shown in
As shown in
The flow velocity calculation unit 82 calculates a flow velocity of air on the basis of an absolute value of the temperature difference. The flow direction calculation unit 83 calculates a flow direction of air on the basis of the positive and negative of the temperature difference. The determination unit 85 compares the flow velocity calculated by the flow velocity calculation unit 82 and the flow direction calculated by the flow direction calculation unit 83 with threshold values stored in the storage unit 84. For example, when a decrease in flow velocity or a reversal of a flow direction is detected only by the second detection device 21B disposed in the downstream region 11B (that is, a temperature difference changes so that the temperature difference decreases), an electric signal used for adjusting the opening degree of the inlet guide vane 11C so that the opening degree increases is transmitted to the inlet guide vane 11C. On the other hand, when a decrease in flow velocity or a reversal of a flow direction is detected only by the first detection device 21A disposed in the upstream region 11A (that is, a temperature difference changes so that the temperature difference decreases), the determination unit 85 transmits an electric signal used for adjusting the opening degree of the blow-off valve V so that the opening degree increases to the blow-off valve V.
An operation of the gas turbine 100 according to the embodiment will be described below. When the gas turbine 100 is operated, first, the compressor 11 is driven using an electric motor or the like (not shown). When the compressor 11 is driven, external air is taken into the compressor 11 via the inlet guide vane 11C and high-pressure air is generated. The combustor 2 mixes fuel with this high-pressure air and burns the mixture to generate high-temperature and high-pressure combustion gas. The turbine 3 is rotationally driven using the combustion gas. A rotational force of the turbine 3 is taken out from a shaft end and used for driving an electric generator (not shown) or the like.
Here, it is known that, when an operation point is changed so that a pressure ratio is increased while the number of revolutions is kept constant in the compressor 11 as described above, a phenomenon called turning stall or surging occurs. Particularly, surging is likely to lead to backflow of a working fluid inside the compressor or vibration of the rotor shaft in some cases. Thus, in the embodiment, the detection device 21 described above detects a flow velocity and a flow direction as physical quantities of air and the control device 90 adjusts either the opening degree of the inlet guide vane 11C and the opening degree of the blow-off valve V on the basis of the flow velocity and the flow direction.
To be specific, it can be determined that, when the temperature difference between the pair of temperature detection units 61 detected by the second detection device 21B for the downstream region 11B decreases, the flow velocity of the working fluid has decreased in the downstream region 11B. When the flow velocity continues to decrease, this is likely to eventually lead to a change in the flow direction in some cases. That is to say, it can be said that a decrease in flow velocity is an indication of backflow. In this case, it can be determined that a flow rate of the working fluid in the downstream region 11B of the compressor 11 becomes excessive and a flow of the working fluid begins to come to a standstill (surging is occurring). Thus, the control device 90 adjusts the opening degree of the inlet guide vane 11C so that the opening degree increases.
On the other hand, it can be determined that, when the temperature difference between the pair of temperature detection units 61 detected by the first detection device 21A for the upstream region 11A decreases, a flow velocity of the working fluid has decreased in the upstream region 11A. In this case, it can be determined that a flow rate of the working fluid in the upstream region 11A of the compressor 11 becomes excessive and a flow of the working fluid begins to come to a standstill (surging is occurring in some cases). Thus, the control device 90 adjusts the opening degree of the blow-off valve V so that the opening degree increases and adjusts an amount of air extracted through the blow-off flow path L so that the extraction amount increases. Thus, for example, when backflow (that is, a change in the flow direction) occurs in the flow of the working fluid inside the compressor or a decrease in the flow velocity that is an indication of backflow occurs, it is possible to immediately detect the backflow and the decrease in the flow velocity.
As described above, according to the constitution associated with the embodiment, at least one of the detection devices 21 is provided for the upstream region 11A and the downstream region 11B of the compressor 11. The detection device 21 detects a physical quantity of the working fluid. The control device 90 detects an abnormality occurring in a flow of the working fluid on the basis of the changes in the physical quantity. The control device 90 adjusts either the opening degree of the inlet guide vane 11C or the extraction amount. Thus, it is possible to eliminate the abnormality occurring in the flow of the working fluid.
Also, according to the above constitution, the detection device 21 has the pair of temperature detection units 61 arranged in the flow direction Df and the heating unit 62 provided between them. When the working fluid passes through the pair of temperature detection units 61 in the flow direction Df, the working fluid is heated by the heating unit 62. Therefore, a difference occurs in a temperature which is detected between the temperature detection unit 61 located on the downstream side in the flow direction Df and the temperature detection unit 61 located the upstream side in the flow direction Df. Therefore, it is possible to detect that the working fluid is flowing toward a side on which the temperature detection unit 61 having a higher detected temperature is located. That is to say, it is possible to detect the flow direction Df of the working fluid. Furthermore, when an absolute value of the temperature difference detected using the pair of temperature detection units 61 is detected, it is also possible to detect changes in the flow velocity of the working fluid. Thus, for example, when backflow (that is, a change in the flow direction) occurs in the flow of the working fluid inside the compressor 11 or a decrease in the flow velocity that is an indication of backflow occurs, these can be detected immediately.
In addition, according to the above constitution, it can be determined that, when the temperature difference between the pair of temperature detection units 61 detected by the detection device 21 of the downstream region 11B decreases, the flow velocity of the working fluid has decreased in the downstream region 11B. When the flow velocity continues to decrease, this is likely to eventually lead to a change in the flow direction. That is to say, it can be said that the decrease in flow velocity is an indication of backflow. In this case, it can be determined that the flow rate of the working fluid in the downstream region 11B of the compressor 11 becomes excessive and the flow of the working fluid begins to come to a standstill (surging is occurring). Thus, the control device 90 adjusts the opening degree of the inlet guide vane 11C so that the opening degree increases. Therefore, the flow rate of the working fluid supplied to the downstream region 11B increases. As a result, surging can be prevented before the development thereof.
Furthermore, according to the above constitution, it can be determined that, when the temperature difference between the pair of temperature detection units 61 detected by the detection device 21 of the upstream region 11A decreases and the flow velocity of the working fluid has decreased in the upstream region 11A. When the flow velocity continues to decrease, this is likely to eventually lead to a change in the flow direction. That is to say, it can be said that the decrease in flow velocity is an indication of backflow. In this case, it can be determined that the flow rate of the working fluid in the upstream region 11A of the compressor 11 becomes excessive and the flow of the working fluid begins to come to a standstill (surging is occurring). Thus, the control device 90 performs adjustment so that an amount of extraction through the blow-off flow path L increases. Therefore, the working fluid coming to a standstill in the upstream region 11A is extracted and the standstill in the flow is eliminated. As a result, surging can be prevented before the development thereof.
Here, it is known that, in the compressor 11 as described above, surging particularly easily occurs in a region further upstream than a rotor blade stage 42 that is a third stage from the furthest upstream side and a region further downstream than a rotor blade stage 42 that is a third stage from the furthest downstream side. According to the above constitution, since these regions are the upstream region 11A and the downstream region 11B, it is possible to detect the occurrence of surging and the indication promptly and accurately.
The first embodiment of the present invention has been described above. Various changes and modifications can be provided to the above constitution without departing from the gist of the present invention. For example, in the above embodiment, the constitution in which the detection device 21 is provided on the inner circumferential surface of the casing 30 in the upstream region 11A and the downstream region 11B has been described.
However, as another example, as shown in
Here, separation or backflow of the working fluid particularly easily occurs on the suction surface Sf2 of the stator blade 41p. According to the above constitution, since the detection device 21 is provided on the suction surface Sf2, it is possible to promptly and accurately detect the separation and the backflow described above.
A second embodiment of the present invention will be described below with reference to
The compressor 211 has a rotor shaft 50 which can rotate around an axis line O, an impeller 5 that is integrally fixed to the rotor shaft 50, and a casing 55 which covers the impeller 5 from an outer circumferential side. The impeller 5 has a disk 51 extending in the radial direction of the axis line O, a plurality of blades 52 provided on a surface of the disk 51 facing upstream, and a cover 53 which covers the blades 52 from the upstream side. An impeller flow path P2 through which air as a working fluid flows is formed between the cover 53, the disk 51, and the blades 52 adjacent to each other.
A guide flow path P1, a diffuser flow path P3, a return bend section P4, and a return flow path P5 communicating with the impeller flow path P2 are provided inside the casing 55. The diffuser flow path P3 communicates with a radially outer end portion of the impeller flow path P2 and extends outward in the radial direction. The return bend section P4 communicates with the radially outer end portion of the diffuser flow path P3 and extends in a direction in which the return bend section P4 is reversed to be directed inward in the radial direction. The blow-off flow path L′ described in the first embodiment described above is connected to the most radially outer side of the return bend section P4. The return flow path P5 communicates with a downstream side of the return bend section P4 and communicates with the guide flow path P1 of a subsequent stage located on the downstream side. A return vane 54 is provided in the return flow path P5.
In such a compressor 211, a region further upstream than the impeller 5 is an upstream region 211A and a region further downstream than the impeller 5 is a downstream region 211B. One (the first detection device 21A) of the detection devices 21 described in the first embodiment described above is provided in the upstream region 211A. To be specific, the first detection device 21A is provided on an inner circumferential surface of the casing 55 in the guide flow path P1. Second detection devices 21B are provided in the downstream region 211B. To be specific, each of the second detection devices 21B are provided on each upstream side wall surface and each downstream side wall surface of the diffuser flow path P3. In addition, each of the second detection devices 21B is provided on an upstream end portion and a downstream end portion of the return vane 54. It is also possible to adopt a constitution in which the second detection device 21B is provided in only one of the diffuser flow path P3 and the return vane 54.
Here, it is known that, in the compressor 211 as described above, surging particularly easily occurs in a region further upstream than the impeller 5 and a region further downstream than the impeller 5. According to the above constitution, since the regions are the upstream region 211A and the downstream region 211B and the detection device 21 is provided each of the regions, it is possible to promptly and accurately detect the occurrence of surging and an indication thereof.
Also, according to the above constitution, since the detection device 21 is provided in at least one of the diffuser flow path P3 and the return flow path P5, it is possible to finely and accurately detect the occurrence of surging and an indication thereof in the downstream region 211B.
The second embodiment of the present invention has been described above. Various changes and modifications can be provided to the above constitution without departing from the gist of the present invention.
A compressor system 200 according to a third embodiment of the present invention will be described below with reference to
As shown in
As shown in
The flow velocity calculation unit 82 calculates a flow velocity (or a flow rate) of air on the basis of an absolute value of the temperature difference. The determination unit 85 compares a flow velocity calculated by the flow velocity calculation unit 82 with a threshold value stored in the storage unit 84. The closing speed determination unit 83b determines a closing speed of the inlet guide vane 11C on the basis of the determination result of the determination unit 85. To be more specific, as shown in
Here, when a command for reducing a load of the compressor 11 (the gas turbine 100) is issued, if the inlet guide vane 11C is closed at an excessively high speed to reduce an amount of air to flow in, there is a risk of there being an amount of air compressed in the downstream region 11B being insufficient and air flowing back to the upstream side (a surge may occur). On the other hand, when the inlet guide vane 11C is closed at an excessively low speed, a temperature of combustion gas decreases due to an excessive amount of air supplied to a combustor 2 provided on the downstream side. As a result, there is a risk of generating combustion vibration and increasing an amount of NOx to be discharged. According to the above constitution, the control device 90 determines a speed at which the inlet guide vane 11C is closed on the basis of the temperature difference detected by means of a pair of temperature detection units 61, that is, a velocity or a flow rate of a fluid. For this reason, it is possible to close the inlet guide vane 11C at an appropriate speed while preventing the surge and the unstable combustion described above. As a result, it is possible to stably and quickly reduce a load of the gas turbine 100.
Also, according to the above constitution, it is possible to determine an optimum speed at which the inlet guide vane 11C is closed simply by evaluating the flow velocity or the flow rate 9 on the basis of the predetermined threshold value. Thus, it is possible to quickly reduce a load of the gas turbine 100 while reducing the likelihood of surges and unstable combustion occurring.
The third embodiment of the present invention has been described above. Various changes and modifications can be provided to the above constitution without departing from the gist of the present invention. For example, the control device 90 described in the third embodiment (that is, the control device 90 further including the closing speed determination unit 83b) can also be combined with and applied to the constitution described in the first embodiment (that is, the constitution in which the first detection device 21A, the blow-off flow path L, and the blow-off valve V are included).
Also, an operation of the closing speed determination unit 83b in the third embodiment is an example. In addition, as another example, it is also possible to constitute a closing speed determination unit 83b so that the process shown in
In the example of
According to the above constitution, it is possible to close the inlet guide vane 11C by selecting a speed determined to correspond to the numerical range to which the detection result of the temperature detection device 21 belongs. That is to say, it is possible to finely determine a speed for closing the inlet guide vane 11C on the basis of the magnitude of the temperature difference (that is, the flow velocity or the flow rate). As a result, it is possible to more quickly reduce a load of the gas turbine 100 while further reducing the likelihood of surges and unstable combustion occurring.
In the example of
According to the above constitution, it is possible to close the inlet guide vane 11C by selecting the speed in accordance with the table in which the relationship between the optimum speed at which the inlet guide vane 11C is closed and the temperature difference (that is, the flow velocity or the flow rate) is shown. That is to say, it is possible to more finely determine the speed at which the inlet guide vane 11C is closed on the basis of the magnitude of the temperature difference. Thus, it is possible to more quickly reduce a load of the gas turbine 100 while further reducing the likelihood of surges and unstable combustion occurring.
According to the present invention, it is possible to provide a compressor system capable of detecting the occurrence of surging with higher accuracy and minimizing surging.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-059225 | Mar 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/012977 | 3/24/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/196504 | 10/1/2020 | WO | A |
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| 20220220978 A1 | Jul 2022 | US |
