Control method and control device for gas turbine engine

Abstract

A control method for a gas turbine engine (9) according to the present disclosure involves: measuring a predetermined operation state amount of the gas turbine engine (9) during operation; reproducing a digital twin of the gas turbine engine (9) from the measured operation state amount; obtaining a reproduction calculation value determined for each of predetermined portions of the gas turbine engine (9) by virtually operating the digital twin on a computer; comparing the reproduction calculation value and a threshold value of the engine state amount determined for each of the predetermined portions of the gas turbine engine (9), and thereby selecting the reproduction calculation value closest to the threshold value; determining a state amount variation rate (R) from the relationship between the selected reproduction calculation value and the threshold value; and controlling the gas turbine engine (9) on the basis of the determined state amount variation rate (R).

Description

Gas turbine engine control method and control device Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2024-060831, filed April 4, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a method and control system for a gas turbine engine.

[0003] In the era of mass introduction of renewable energy, there is an increasing demand for power generation systems equipped with gas turbines as peak power sources. Power generation systems used as peak power sources are required to have a high load fluctuation rate. However, when gas turbines are controlled at high load fluctuation rates, particularly at high load increase rates, the thermal load caused by sudden load fluctuations narrows the tip clearance, causing rotating system components to come into contact with stationary components. This can lead to wear, increasing the clearance between the rotor blades and the casing, and potentially reducing engine performance. Furthermore, increased thermal stress can exceed the component tolerances, potentially damaging the gas turbine engine.

[0004] Japanese Patent Laid-Open Publication No. 2022-89319 (Patent Document 1) describes a load adjustment method that determines an upper limit of a load increase rate in accordance with a warm-up parameter that indicates the degree of warm-up of a gas turbine during load operation, and increases the load rate of the gas turbine at or below the determined upper limit of the load increase rate, thereby enabling load adjustment at as high a load increase rate as possible within a range that does not cause turbine damage.

[0005] In recent years, digital twin technology has been developed, which uses IoT and other technologies to collect information about operating physical equipment in real time, send it to a virtual space on a computer, and recreate the environment of the physical equipment within that virtual space. In a digital twin, a twin of the physical equipment is recreated as a model in a virtual space. The model reflects the current state of the equipment and includes historical data related to the equipment. Digital twins can be used not only to evaluate the current state of equipment, but also to predict future operation, improve control, or optimize operations.

[0006] Japanese Patent Application Laid-Open No. 2022-89319

[0007] According to the invention of Patent Document 1, the upper limit of the load increase rate is determined based on the temperature difference between the casing and the rotor, and warm-up parameters such as the most recent load factor. However, depending on the operating environment, etc., there is a possibility that the predicted upper limit of the load increase rate may differ from the actual upper limit, which raises doubts about the accuracy of the determined load increase rate.

[0008] The disclosure of the present application has been made to solve the above-mentioned problems, and provides a control method and control device for a gas turbine engine that predicts tip clearance and thermal stress of components with high accuracy and optimizes the rate of change of state quantities.

[0009] A method for controlling a gas turbine engine according to one embodiment of the present disclosure measures predetermined operating state quantities of a gas turbine engine during operation, recreates a digital twin of the gas turbine engine from the measured operating state quantities, virtually operates the digital twin on a computer to obtain a reproduced calculated value determined for each predetermined part of the gas turbine engine, compares threshold values ​​for engine state quantities determined for each predetermined part of the gas turbine engine with the reproduced calculated value to select the reproduced calculated value closest to the threshold value, determines a state quantity fluctuation rate from the relationship between the selected reproduced calculated value and the threshold value, and controls the gas turbine engine based on the determined state quantity fluctuation rate.

[0010] According to a gas turbine engine control method according to one embodiment of the present disclosure, predetermined operating state quantities of the gas turbine engine are measured, a digital twin of the gas turbine engine is reproduced from the operating state quantities, and the digital twin is virtually operated on a computer to obtain reproduced calculation values ​​determined for each predetermined part of the gas turbine engine. This makes it possible to predict state quantities such as tip clearance and thermal stress of components with high accuracy and optimize the rate of change of the state quantities.

[0011] Any combination of at least two features disclosed in the claims and / or the specification and / or the drawings is included in the present disclosure. In particular, any combination of two or more of the claims is included in the present disclosure.

[0012] The present disclosure will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation purposes and should not be used to define the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims. In the accompanying drawings, the same part numbers in multiple drawings indicate the same or corresponding parts. A schematic diagram showing a power generation system of a gas turbine engine according to the present disclosure. A flowchart showing an embodiment of a control method for a gas turbine engine according to the present disclosure. A diagram showing a load factor transition during cold start-up in an embodiment of the present disclosure. A diagram showing a tip clearance transition in an embodiment of the present disclosure. A diagram showing a thermal stress transition of a rotor blade in an embodiment of the present disclosure. A diagram showing a load factor transition during hot start-up in an embodiment of the present disclosure.

[0013] An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a power generation system for a gas turbine engine (GT) 9 according to one embodiment of the present disclosure. In the figure, the gas turbine engine 9 includes, as main components, a compressor 1, a combustor 2, and a turbine 3. Compressed air A supplied from the compressor 1 and fuel supplied from a fuel supply device (not shown) are combusted in the combustor 2, and high-temperature, high-pressure combustion gas G generated by the combustion is supplied to the turbine 3 to drive the turbine 3. Exhaust gas E is discharged from the turbine 3. The compressor 1 is driven by the turbine 3 via a rotary shaft 4, and the turbine 3 also drives an external load 6, such as a generator, via a reduction gear 5.

[0014] An intake air temperature measuring device T1 for measuring intake air temperature and an intake air pressure measuring device P1 for measuring intake air pressure are provided at the inlet of the compressor 1. A compressor outlet temperature measuring device T2 for measuring the outlet temperature of the compressor 1 and a compressor outlet pressure measuring device P2 for measuring the outlet pressure of the compressor 1 are provided at the outlet of the compressor 1. An exhaust air temperature measuring device T3 for measuring the exhaust air temperature and an exhaust air pressure measuring device P3 for measuring the exhaust air pressure are provided at the outlet of the turbine 3. The intake air temperature measuring device T1, the compressor outlet temperature measuring device T2, and the exhaust air temperature measuring device T3 are temperature sensors such as thermistors, and the intake air pressure measuring device P1, the compressor outlet pressure measuring device P2, and the exhaust air pressure measuring device P3 are, for example, mechanical pressure sensors.

[0015] In the following description, unless otherwise specified, the terms "axial direction," "radial direction," and "circumferential direction" refer to the axial direction, radial direction, and circumferential direction of the gas turbine engine 9, respectively.

[0016] 2 shows a flowchart of a control method for a gas turbine engine 9 according to one embodiment. When a start-of-operation command is issued from the control device 10 of the gas turbine engine 9, the temperatures measured by the temperature sensors T1, T2, and T3 and the pressures measured by the pressure sensors P1, P2, and P3 change (S1). A gas turbine digital twin model (hereinafter referred to as a GTDTM or digital twin), which is a computer-based model of the gas turbine engine 9, is generated from the temperatures and pressures measured in the actual engine. The GTDTM is then virtually operated on the computer, whereby all predetermined engine state quantities of the gas turbine engine 9 are reproduced and calculated on the computer (S2). In this disclosure, the measured temperatures, pressures, and the like of the actual engine are referred to as operating state quantities. However, the predetermined engine state quantities reproduced and calculated on the computer include not only the temperatures and pressures but also the tip clearances between the radial leading edges of the rotor blades of each stage of the gas turbine engine 9 and the inner surface of the casing, the thermal stress and lifespan of major components constituting the gas turbine engine 9, flow characteristics such as rotating stall, and flow rate changes.

[0017] By operating the GTDTM in a virtual space, predetermined engine state quantities of the gas turbine engine 9 at the current time are reproduced and calculated. The reproduced calculated values ​​of each engine state quantity are compared with threshold values ​​determined for each predetermined portion of the gas turbine engine 9, and the reproduced calculated value closest to the threshold value is selected (S3). For example, the threshold value is a lower limit value for tip clearance below which the rotor blades and the casing will come into contact, and a higher limit value for thermal stress above which the components will be destroyed or broken. The predetermined portion refers to, for example, the outlets of the compressor 1 and the turbine 3, and the radial tips of the rotor blades of each stage of the gas turbine engine 9, but is not limited to these, and may be any portion of the gas turbine engine 9 whose state quantities are to be grasped.

[0018] A state quantity variation rate R is determined from the relationship between the selected reproduced calculated value and the threshold value (S4). The state quantity variation rate R refers to the load variation rate of the load 6 of the gas turbine engine 9 that is increased or decreased so as not to exceed the threshold value of the selected engine state quantity. In this embodiment, since control is performed to increase the load rate of the load 6, the state quantity variation rate R refers to the load increase rate. When control is performed to decrease the load rate, the state quantity variation rate R refers to the load decrease rate.

[0019] The determined load increase rate is set as the output value of the GTDTM (S5), and this output value is set as the input value to the control device 10 of the gas turbine engine 9 (S6). The load 6 of the gas turbine engine 9 is adjusted based on the input load increase rate R, and the process returns to the first step S1 of the flowchart. Thereafter, by repeating the above-described control method, the load rate is aimed at 100% as soon as possible without causing damage to the turbine or destruction of parts.

[0020] 3 shows the load factor of the gas turbine engine 9 over time during a cold start according to this embodiment and over time during a conventional cold start. A cold start refers to an operation in which the load factor is increased from a state in which the gas turbine engine 9 is completely stopped and the internal temperature of the gas turbine engine 9 is the same as the ambient temperature. The conventional load factor over time refers to the load factor over time when the load increase rate is constant.

[0021] When the rotation speed of the turbine 3 reaches the rated value, the load is increased based on the load increase rate R optimized by the digital twin. As a result, the time required to reach a full load, or a load factor of 100%, can be significantly reduced from the conventional T1 to T2 according to the present disclosure. Furthermore, by optimizing not only the load increase rate R but also the timing at which the load increase can begin, the timing at which the load increase begins can be advanced compared to conventional load increases that do not use a control method using a digital twin. By increasing the load increase rate R and advancing the timing at which the load increase begins, the time required to reach a full load, or a load factor of 100%, can be significantly reduced.

[0022] FIG. 4 shows the tip clearance transition of the gas turbine engine 9 according to the present disclosure and the tip clearance transition of the conventional gas turbine engine 9. The conventional tip clearance transition is the tip clearance transition when the load increase rate is constant. As described in FIG. 3 , the load increase rate R according to the present disclosure is higher than the conventional load increase rate, so the internal temperature of the gas turbine engine 9 rises rapidly. When the components are exposed to high temperatures and thermally expand, the blades and the casing approach each other, and the clearance reaches the threshold value, which is the lower allowable limit, earlier than in the conventional example. When the tip clearance approaches the threshold value, the load increase rate R is optimized using the digital twin, and the load increase rate R is adjusted so that the blades and the casing do not come into contact. Thereafter, the load increase rate R is continuously adjusted so that the load rate reaches 100% earlier.

[0023] FIG. 5 shows the transition of thermal stress in the rotor blade of the gas turbine engine 9 according to the present disclosure and the transition of thermal stress in the rotor blade of a conventional gas turbine engine 9. The transition of thermal stress in the conventional rotor blade is the transition of thermal stress in the rotor blade when the load increase rate is constant. As described in FIG. 3 , the load increase rate R of the present disclosure is higher than the conventional load increase rate, so the internal temperature of the gas turbine engine 9 rises rapidly. As the components are exposed to high temperatures and the thermal stress in the rotor blade increases, the threshold value of the thermal stress in the rotor blade approaches the allowable upper limit value more quickly than in the conventional example. When the thermal stress in the rotor blade approaches the threshold value, the load increase rate R is optimized using the digital twin, and the load increase rate R is adjusted so that it does not exceed the allowable upper limit value of the thermal stress in the rotor blade. Thereafter, the load increase rate R is continuously adjusted so that the load rate reaches 100% as soon as possible.

[0024] 6 shows the transition of the load factor of the gas turbine engine 9 during a hot start according to the present disclosure and the transition of the load factor of the gas turbine engine 9 during a conventional hot start. A hot start refers to an operation in which the gas turbine engine 9 is stopped after operation and the load factor is increased from a state in which the internal temperature of the gas turbine engine 9 is higher than the ambient temperature. During a hot start, the tip clearance is narrow and the thermal stress on the rotor blades and the like is large. Therefore, after the gas turbine engine 9 is stopped, a certain cooling time must be allowed before restarting. In a conventional hot start, it is difficult to accurately predict the current state of the tip clearance, the thermal stress on the rotor blades, and the like, so restarting the gas turbine engine 9 is prohibited for several hours after the engine is stopped.

[0025] Even when the gas turbine engine 9 is stopped, which is one of the operating states of the gas turbine engine 9, all predetermined engine state quantities of the gas turbine engine 9 are reproduced and calculated on a computer by virtually operating the digital twin from the temperatures measured by the temperature sensors T1, T2, and T3 and the pressures measured by the pressure sensors P1, P2, and P3 in Figure 1. The reproduced calculated values ​​of each engine state quantity are compared with threshold values ​​set for each predetermined part of the gas turbine engine 9, and the reproduced calculated value closest to the threshold value is selected. Based on the selected reproduced calculated value, it is determined whether the gas turbine engine 9 can be started, and if it is possible, the gas turbine engine 9 is started.

[0026] After startup, which is another operating state of the gas turbine engine 9, and before load increase, all predetermined engine state quantities of the gas turbine engine 9 are reproduced and calculated on a computer by virtually operating the digital twin from the temperatures measured by the temperature sensors T1, T2, and T3 and the pressures measured by the pressure sensors P1, P2, and P3 in Figure 1. The reproduced calculated values ​​of each engine state quantity are compared with threshold values ​​set for each predetermined part of the gas turbine engine 9, and the reproduced calculated value closest to the threshold value is selected. Based on the selected reproduced calculated value, it is determined whether or not load increase on the gas turbine engine 9 can be started, and if it is possible, load increase on the gas turbine engine 9 is started.

[0027] Thereafter, when the rotation speed of the turbine 3 reaches the rated value, the load is increased based on the load increase rate R optimized by the digital twin, just as in the cold start-up shown in Figure 3. That is, even in the hot start-up shown in Figure 6, by optimizing the load increase rate R and the timing at which load increase can begin, a higher load increase rate can be achieved and the timing at which load increase can begin can be advanced compared to conventional load increases that do not use a control method based on a digital twin. By increasing the load increase rate R and advancing the timing at which start-up is possible, the time required to reach a load rate of 100%, which is full load, can be significantly shortened.

[0028] According to the control method for the gas turbine engine 9 disclosed herein, various engine state quantities of the gas turbine engine 9 are accurately predicted using a digital twin, and the load is increased based on an optimized load increase rate R, thereby significantly shortening the time required to reach a load rate of 100% without causing damage to the turbine or destruction of parts.

[0029] The operating state quantities may include at least temperature and pressure. In the configuration of the present disclosure, predetermined engine state quantities of the gas turbine engine 9 can be reproduced and calculated using a digital twin from the minimum necessary measurement results of at least temperature and pressure.

[0030] The reproduced calculated values ​​may be the clearance between the rotor blades and the casing at each stage of the gas turbine engine 9. When the rotor blades come into contact with the casing, the clearance between the rotor blades and the casing increases due to wear, resulting in a decrease in engine performance. If the tip clearance can be accurately predicted using the digital twin, it is possible to avoid contact between the rotor blades and the casing during operation and prevent a decrease in engine performance.

[0031] The state quantity fluctuation rate R may be a load fluctuation rate of the load 6 of the gas turbine engine 9 that is increased or decreased so as not to exceed a threshold value of the selected reproduced calculated value. By operating the gas turbine engine 9 so as not to exceed the threshold value of the selected reproduced calculated value, it is possible to aim for a load factor of 100% early while avoiding damage or destruction of parts due to contact between the rotor blades and the casing, etc.

[0032] When the gas turbine engine 9 is stopped, it may be determined whether or not to start the gas turbine engine 9 based on the reproduced calculation value. In the configuration of the present disclosure, the start-up possible timing is optimized during hot start-up, thereby significantly shortening the time required to reach a load factor of 100%.

[0033] After starting the gas turbine engine 9 and before the load is increased, it may be determined from the reproduced calculation value whether or not to start increasing the load of the gas turbine engine 9. In the configuration of the present disclosure, by optimizing the timing at which the load can be increased, the timing at which the load can be increased can be made earlier than in conventional load increases that do not use a control method using a digital twin.

[0034] The present disclosure also includes the following control device for a gas turbine engine 9. The control device includes state quantity measuring means for measuring predetermined operating state quantities of the gas turbine engine 9 during operation, reproduction calculation means for recreating a digital twin of the gas turbine engine from the measured operating state quantities and virtually operating the digital twin on a computer to obtain a reproduced calculated value determined for each predetermined portion of the gas turbine engine, selection means for comparing threshold values ​​for engine state quantities determined for each predetermined portion of the gas turbine engine 9 with the reproduced calculated value and selecting the reproduced calculated value that is closest to the threshold value, state quantity fluctuation rate determining means for determining a state quantity fluctuation rate R from the relationship between the selected reproduced calculated value and the threshold value, and load adjustment means for adjusting the load of the gas turbine engine 9 based on the determined state quantity fluctuation rate R.

[0035] According to the control device for the gas turbine engine 9 disclosed herein, various engine state quantities of the gas turbine engine 9 are accurately predicted using a digital twin, and the load is increased based on an optimized load increase rate, thereby significantly shortening the time required to reach a load rate of 100% without causing damage to the turbine or destruction of parts.

[0036] As described above, the preferred embodiments of the present disclosure have been described with reference to the drawings, but various additions, modifications, and deletions can be made without departing from the spirit of the present disclosure. Therefore, such additions, modifications, and deletions are also included in the scope of the present disclosure.

[0037] 9... Gas turbine engine 10... Gas turbine engine control device R... State quantity fluctuation rate (load increase rate)

Claims

1. A method for controlling a gas turbine engine, comprising: measuring predetermined operating state quantities of a gas turbine engine during operation; recreating a digital twin of the gas turbine engine from the measured operating state quantities; virtually operating the digital twin on a computer to obtain reproduced calculated values ​​determined for each predetermined part of the gas turbine engine; comparing the reproduced calculated values ​​with threshold values ​​for engine state quantities determined for each predetermined part of the gas turbine engine, and selecting the reproduced calculated value that is closest to the threshold value; determining a state quantity fluctuation rate from the relationship between the selected reproduced calculated value and the threshold value; and controlling the gas turbine engine based on the determined state quantity fluctuation rate.

2. A method for controlling a gas turbine engine according to claim 1, wherein the operational state variables include at least temperature and pressure.

3. A control method for a gas turbine engine according to claim 1 or 2, wherein the reproduced calculated value is the clearance between the moving blades of each stage of the gas turbine engine and the casing.

4. A method for controlling a gas turbine engine according to claim 1 or 2, wherein the state quantity fluctuation rate is a load fluctuation rate of the load of the gas turbine engine which is increased or decreased so as not to exceed the threshold value of the selected reproduced calculated value.

5. A method for controlling a gas turbine engine according to claim 1 or 2, wherein, when the operation of the gas turbine engine is stopped, it is determined from the reproduced calculated values ​​whether or not the gas turbine engine can be started.

6. A method for controlling a gas turbine engine according to claim 1 or 2, wherein after starting the gas turbine engine and before increasing the load, it is determined from the reproduced calculated values ​​whether or not to start increasing the load on the gas turbine engine.

7. A control device for a gas turbine engine comprising: a state quantity measuring means for measuring predetermined operating state quantities of a gas turbine engine during operation; a reproduction calculation means for recreating a digital twin of the gas turbine engine from the measured operating state quantities and virtually operating the digital twin on a computer to obtain a reproduced calculated value determined for each predetermined part of the gas turbine engine; a selection means for comparing the reproduced calculated value with threshold values ​​for engine state quantities determined for each predetermined part of the gas turbine engine, and selecting the reproduced calculated value that is closest to the threshold value; a state quantity fluctuation rate determination means for determining a state quantity fluctuation rate from the relationship between the selected reproduced calculated value and the threshold value; and a load adjustment means for adjusting the load of the gas turbine engine based on the determined state quantity fluctuation rate.

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