A method, device and equipment for regulating the differential expansion of a multi-cylinder steam turbine and a storage medium

Abstract

The application discloses a multi-cylinder steam turbine expansion difference regulation method and device, equipment and storage medium, relates to the technical field of power generation equipment, and comprises the following steps: collecting the temperature of each cylinder shaft in the multi-cylinder steam turbine and the expansion difference value of the cylinder and the corresponding rotor in real time, and determining the cylinder shaft thermal expansion distribution curve; the rotor shaft thermal expansion total amount is obtained in combination with the cylinder shaft thermal expansion distribution curve and the expansion difference value of the corresponding rotor; according to the cylinder shaft thermal expansion distribution curve, the rotor shaft thermal expansion distribution curve and the relative reference position of the cylinder and the rotor, the real-time dynamic-static gap of each part of the static part and the rotating part of the multi-cylinder steam turbine is determined and evaluated, the best displacement amount of the push rod is determined, and the distance between adjacent cylinders is moved to the best value by controlling the push rod assembly. The application overcomes the problems of dynamic-static rubbing and serious lag of the thermal response of the cylinder relative to the rotor that may be caused by the natural thermal expansion difference of the cylinder and the rotor during the starting, stopping and rapid load changing process of the steam turbine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power generation equipment, in particular to a multi-cylinder steam turbine expansion difference regulation method, device, equipment and storage medium. BACKGROUND

[0002] The steam turbine is the core equipment of thermal power generation, and its main function is to convert the heat energy and pressure energy of high-temperature and high-pressure steam into rotary mechanical energy to drive the generator to generate electricity.

[0003] The steam turbine mainly consists of rotating parts (including rotors, wheel discs and moving blades, etc.) and stationary parts (including cylinders, diaphragms and stationary blade rings, etc.). In order to improve the thermal efficiency of the steam turbine, the axial clearances of the moving blades and the stationary blades are very small, usually within 1.5-30 mm. For large coal-fired generating units, the working temperature of the high-temperature parts of the steam turbine is as high as 500-650℃, and the total thermal expansion of the rotor can exceed 60 mm. Considering that the stationary parts such as the cylinder will also produce thermal expansion similar to the rotor at high temperature, as long as the thermal expansion directions of the corresponding parts of the rotor and the cylinder are consistent, the dynamic and static rubbing can be avoided during the normal operation of the unit. However, due to the large size and high working pressure of the steam turbine cylinder valve, sufficient wall thickness is required to meet the strength and stiffness requirements, resulting in a much larger thermal inertia than the rotor. In order to ensure the safety of the equipment, the temperature rise rate must be controlled during the start-up process of the unit to ensure that the thermal expansion difference (referred to as expansion difference) between the cylinder and the rotor is within the range that does not produce dynamic and static rubbing, which is also the case during shutdown, making the start-up and shutdown time of the steam turbine very long. Taking a 1000 MW thermal power unit as an example, its cold start-up time usually exceeds 4 hours, which has become a major obstacle to the flexible operation of the unit.

[0004] Further research on the existing steam turbine cylinder and rotor expansion difference control methods at home and abroad shows that the expansion difference of the steam turbine is mainly controlled by the transverse pin, longitudinal pin and vertical pin arranged between the cylinder and the bedplate or the outer cylinder and the inner cylinder to control the thermal expansion direction of different cylinders and reduce the difference in thermal expansion amount between the cylinder and the corresponding position of the rotor. Since a large steam turbine usually consists of 2-6 rotors and corresponding cylinders, the rotors are connected together through shaft couplings, and the dead point position of the rotor (the axial expansion amount relative to the foundation of the unit is 0) is the thrust disc, which starts to expand thermally from the dead point position to both ends, and the expansion amount is transmitted and accumulated between different rotors; however, each cylinder is independently placed on the bedplate, and the thermal expansion of one cylinder does not transmit to the adjacent cylinder, resulting in a serious deviation of the axial displacement amount of the cylinder thermal expansion from the cumulative thermal expansion amount of the rotor, and the farther the cylinder is from the dead point of the rotor, the more serious the deviation, as shown in the accompanying Figure 1

[0005] ​In order to reduce the expansion difference of the steam turbine, the large steam turbine of Siemens in Germany adopts the push rod bolt arranged symmetrically to connect each cylinder, and the thermal expansion amount of the cylinder under the hot state is transmitted to the adjacent cylinder through the push rod, so that the expansion difference between the cylinder and the rotor is far less than that of other steam turbines with the same number of cylinders, and the axial gap between the stationary blade and the moving blade can be further reduced to improve the efficiency of the steam turbine. However, the above scheme does not solve the problem that the thermal response of the cylinder lags behind the rotor, but only transmits the thermal expansion result of the cylinder at this time, which is more effective for reducing the expansion difference of the steam turbine in the normal operation state, and has limited effect on the expansion difference control in the starting and stopping process of the steam turbine. SUMMARY

[0006] The application provides a multi-cylinder steam turbine expansion difference regulation method, device, equipment and storage medium, which solves the problems of large expansion difference and long warm-up time in the starting and stopping process of the existing large multi-cylinder steam turbine.

[0007] The application provides a multi-cylinder steam turbine expansion difference regulation method, which comprises the following steps:

[0008] The temperature on the axial direction of each cylinder in the multi-cylinder steam turbine and the expansion difference value between the cylinder and the corresponding rotor are collected in real time, and the axial thermal expansion distribution curve of the cylinder is determined according to the temperature on the axial direction of each cylinder;

[0009] The total amount of the axial thermal expansion of the rotor is obtained in combination with the axial thermal expansion distribution curve of the cylinder and the expansion difference value between the cylinder and the corresponding rotor, and the axial thermal expansion distribution curve of the rotor is obtained according to the total amount of the axial thermal expansion of the rotor based on the axial thermal expansion model of the rotor;

[0010] The real-time dynamic-static gap of each part of the stationary part and the rotating part of the multi-cylinder steam turbine is determined according to the axial thermal expansion distribution curve of the cylinder, the axial thermal expansion distribution curve of the rotor and the relative reference position between the cylinder and the rotor;

[0011] The real-time dynamic-static gap is evaluated, and the best displacement amount of the push rod is determined according to the evaluation result, wherein the push rod is used to connect adjacent cylinders.

[0012] Based on the best displacement amount of the push rod, the distance between the adjacent cylinders is moved to the best value by the push rod assembly, so as to realize the expansion difference regulation of the multi-cylinder steam turbine.

[0013] Preferably, the multi-cylinder steam turbine refers to a thermal power generation, atomic energy generation, solar heat generation and gas-steam combined cycle steam turbine comprising 2-6 cylinders; the axial temperature of each cylinder in the steam turbine is monitored by a plurality of temperature sensors, the expansion difference value between each cylinder and the corresponding rotor is monitored by an expansion difference sensor, and the monitored temperature and expansion difference value are collected in real time by a data acquisition system.

[0014] Preferably, the rotor axial thermal expansion model is a rotor axial thermal expansion distribution characteristic and total amount relationship model with the steam inlet temperature, which is determined by three-dimensional numerical simulation.

[0015] Preferably, the real-time dynamic-static gap is evaluated, and the optimal displacement amount of the push rod is determined according to the evaluation result, including the following steps:

[0016] The safety margin of the dynamic-static gap is evaluated based on design parameters and empirical data;

[0017] The cylinder connecting pipeline is analyzed for stress and thrust to determine the adjustable amount of the cylinder axial displacement;

[0018] The optimal displacement amount of the push rod is obtained according to the safety margin of the dynamic-static gap and the adjustable amount of the cylinder axial displacement.

[0019] Preferably, the push rod is supported at both ends on the outer cylinder or the inner cylinder of the adjacent cylinder, and moves the outer cylinder or the inner cylinder or moves both the inner and outer cylinders; the push rod is one of a thermal expansion push rod, a hydraulic push rod, an electric push rod, an electric heating push rod, and other large-thrust and small-displacement adjustable push rods.

[0020] Preferably, when the thermal expansion push rod is selected, the push rod assembly includes a thermal expansion push rod, both ends of which are connected to the cylinder through a push rod connecting piece, and inside which is provided with a reinforced heat exchange element; a fluid inlet is provided through the outside of one end of the thermal expansion push rod, and a fluid outlet is provided through the outside of the other end; a thermal insulation layer is provided outside the thermal expansion push rod;

[0021] When the thermal expansion push rod needs to be elongated, hot fluid with a temperature higher than that of the thermal expansion push rod is introduced from the fluid inlet, and the thermal expansion push rod is rapidly heated with the assistance of the reinforced heat exchange element, so that the thermal expansion push rod is expanded, and the heat-exchanged fluid is discharged from the fluid outlet;

[0022] When the thermal expansion push rod needs to be contracted, cold fluid with a temperature lower than that of the thermal expansion push rod is introduced from the fluid inlet, and the thermal expansion push rod is rapidly cooled with the assistance of the reinforced heat exchange element, so that it is cold contracted, and the heat-exchanged fluid is discharged from the fluid outlet.

[0023] Preferably, when the hydraulic push rod is selected, the push rod assembly includes a hydraulic push rod, one end of which is connected to the cylinder through a push rod piston connecting piece, and the other end of which is directly connected to the cylinder; a first fluid interface is provided through the outside of one end of the hydraulic push rod, and a second fluid interface is provided through the outside of the other end;

[0024] When the hydraulic push rod needs to be elongated, high-pressure liquid is discharged from the first fluid interface, and high-pressure liquid is supplemented from the second fluid interface, so that the push rod piston connecting piece moves outward;

[0025] When the hydraulic push rod needs to be shortened, high-pressure liquid is supplemented from the first fluid interface, high-pressure liquid is discharged from the second fluid interface, and the push rod piston connector moves inward.

[0026] A steam turbine differential expansion regulating device comprises:

[0027] The acquisition module is configured to acquire, in real time, the temperature on the axial direction of each cylinder of the multi-cylinder steam turbine and the differential expansion value of the cylinder and the corresponding rotor, and determine a cylinder axial thermal expansion distribution curve based on the temperature on the axial direction of each cylinder.

[0028] The acquisition module is configured to acquire, in real time, the temperature on the axial direction of each cylinder of the multi-cylinder steam turbine and the differential expansion value of the cylinder and the corresponding rotor, and determine a cylinder axial thermal expansion distribution curve based on the temperature on the axial direction of each cylinder.

[0029] The determination module is configured to determine the real-time dynamic-static gap at each position of the static part and the rotating part of the multi-cylinder steam turbine based on the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve and the relative reference position of the cylinder and the rotor.

[0030] The evaluation module is configured to evaluate the real-time dynamic-static gap, and determine the optimal displacement amount of the push rod based on the evaluation result, the push rod being used to connect adjacent cylinders.

[0031] The control module is configured to control the push rod assembly to move the distance between adjacent cylinders to an optimal value based on the optimal displacement amount of the push rod, so as to realize the differential expansion regulation of the multi-cylinder steam turbine.

[0032] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steam turbine differential expansion regulating method described above when executing the program.

[0033] A computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steam turbine differential expansion regulating method described above.

[0034] Compared with the prior art, the beneficial effects of the present application are:

[0035] The application firstly collects the temperature of each cylinder in the multi-cylinder steam turbine and the expansion difference between the cylinder and the corresponding rotor, determines the cylinder axial thermal expansion distribution curve and the rotor axial thermal expansion distribution curve. According to the cylinder axial thermal expansion distribution curve and the rotor axial thermal expansion distribution curve, the real-time dynamic and static clearance of the static part and the rotating part of the multi-cylinder steam turbine is determined and evaluated, the best displacement amount of the push rod is determined according to the evaluation result, and finally the distance between the adjacent cylinders is moved to the best value by the push rod assembly. The application overcomes the problems of dynamic and static rubbing caused by the natural thermal expansion difference between the cylinder and the rotor during the start, stop and rapid load change of the steam turbine, and the serious lag of the thermal response of the cylinder relative to the rotor, and can realize the high-speed and high-load rapid warm-up of the steam turbine, and significantly improves the start-stop and load change speed of the steam turbine. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0037] Figure 1 It is a schematic diagram of the thermal expansion of the multi-cylinder steam turbine of the present application.

[0038] Figure 2 It is a system block diagram of the expansion difference regulation method of the multi-cylinder steam turbine of the present application.

[0039] Figure 3 It is a structural schematic diagram of the multi-cylinder steam turbine of the present application.

[0040] Figure 4 It is a schematic diagram of the push rod assembly of the thermal expansion push rod selected by the present application.

[0041] Figure 5 It is a schematic diagram of the push rod assembly of the hydraulic push rod selected by the present application.

[0042] In the figure: 1-first rotor, 2-first cylinder, 3-second rotor, 4-second cylinder, 5-third rotor, 6-third cylinder, 7-temperature sensor, 8-expansion difference sensor, 9-push rod assembly, 10-bearing, 11-push rod connecting piece, 12-thermal expansion push rod, 13-thermal insulation layer, 14-fluid inlet, 15-strengthened heat exchange element, 16-fluid outlet, 17-push rod piston connecting piece, 18-hydraulic push rod, 19-first fluid interface, 20-second fluid interface. DETAILED DESCRIPTION

[0043] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described in order to make the technical solutions in the embodiments of the present application apparent to those skilled in the art. Obviously, the described embodiments are only a part rather than all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts should fall into the scope of the present application.

[0044] In order to shorten the start-up and shutdown time of the steam turbine, the present application proposes a multi-cylinder steam turbine expansion difference regulation method based on the push rod bolt idea of Siemens Company and the expansion difference and cylinder temperature monitoring, specifically an expansion difference intelligent regulation method for the rapid start-stop of multi-cylinder steam turbine, which can be popularized and applied to the rapid start-stop and rapid load change of multi-cylinder steam turbine, and improve the flexibility of unit operation. Figure 2 The present application includes an expansion difference intelligent regulation system, which includes a cylinder temperature distribution monitoring system, a rotor and cylinder expansion difference monitoring system, an intelligent dynamic-static gap evaluation system and a cylinder intelligent push rod system. According to the real-time monitoring results of the cylinder temperature distribution and the expansion difference of each cylinder and rotor, in combination with the rotor axial thermal expansion model and the stress and thrust analysis of the cylinder connecting pipe, the real-time dynamic-static gap, safety margin and adjustable range of each part of the stationary and rotating parts of the steam turbine are comprehensively evaluated, the optimal displacement amount of the push rod in the current state is determined, and then the axial distance between the adjacent cylinders is adjusted to the optimal value through the extension and retraction of the adjustable push rod. Specifically, the following steps are included:

[0045] Step 1: Real-time acquisition of the temperature on the axial direction of each cylinder in the multi-cylinder steam turbine and the expansion difference between the cylinder and the corresponding rotor, and determination of the cylinder axial thermal expansion distribution curve according to the temperature on the axial direction of each cylinder.

[0046] In the present embodiment, the multi-cylinder steam turbine refers to a thermal power generation, atomic energy generation, solar thermal power generation and gas-steam combined cycle steam turbine including 2-6 cylinders.

[0047] The expansion difference intelligent regulation system is not only used for the start-up and shutdown of the multi-cylinder steam turbine, but also can be used for the load regulation and stable operation of the steam turbine.

[0048] The cylinder temperature distribution monitoring system is composed of a plurality of temperature sensors 7 installed at typical positions of each cylinder and a data acquisition system, etc., and is used for real-time monitoring of the temperature distribution of each cylinder. The cylinder axial thermal expansion distribution curve can be determined according to the cylinder temperature distribution.

[0049] The rotor and cylinder expansion difference monitoring system is composed of an expansion difference sensor 8 installed at typical positions of each cylinder and rotor and a data acquisition system, etc., and is used for real-time monitoring of the expansion difference between each cylinder and the corresponding rotor.

[0050] Figure 3 ​The steam turbine in the embodiment includes, from left to right, a first rotor 1 sleeved on a bearing 10, a first cylinder 2, a second rotor 3, a second cylinder 4, a third rotor 5, and a third cylinder 6. Each cylinder is provided with a temperature sensor 7, and each corresponding rotor is provided with a differential expansion sensor 8. A push rod assembly 9 is arranged between two adjacent cylinders.

[0051] In the second step, the total rotor axial thermal expansion is obtained by combining the cylinder axial thermal expansion distribution curve and the differential expansion value of the corresponding rotor. The rotor axial thermal expansion distribution curve is obtained based on the rotor axial thermal expansion model according to the total rotor axial thermal expansion.

[0052] The total rotor axial thermal expansion can be determined according to the cylinder axial thermal expansion distribution curve and the differential expansion monitoring result. Further, the rotor axial thermal expansion distribution curve can be determined in combination with the rotor axial thermal expansion model.

[0053] In the embodiment, the rotor axial thermal expansion model refers to a relationship model of the rotor axial thermal expansion distribution characteristic, the total rotor axial thermal expansion, and the inlet steam temperature, which can be determined by three-dimensional numerical simulation or special test.

[0054] In the third step, the real-time dynamic-static gap at each position of the static part and the rotating part of the multi-cylinder steam turbine is determined according to the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve, and the relative reference position of the cylinder and the rotor.

[0055] The main function of the dynamic-static gap intelligent evaluation system is to determine the real-time dynamic-static gap at each position of the static part and the rotating part of the steam turbine according to the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve, and the relative reference position of the cylinder and the rotor.

[0056] In the fourth step, the real-time dynamic-static gap is evaluated, and the optimal displacement amount of the push rod is determined according to the evaluation result. The push rod is used to connect adjacent cylinders.

[0057] The safety margin of the dynamic-static gap can be evaluated in combination with the design parameters and empirical data. The optimal displacement amount of the push rod can be evaluated by comprehensively analyzing the safety margin of the dynamic-static gap and the adjustable amount of the cylinder axial displacement.

[0058] The adjustable amount of the cylinder axial displacement is mainly limited by the stress and thrust of the cylinder connecting pipe, which needs to be analyzed and determined. If necessary, the design of the cylinder connecting pipe needs to be improved to increase the adjustable range of the cylinder axial displacement.

[0059] In the fifth step, based on the optimal displacement amount of the push rod, the push rod assembly is controlled to move the distance between adjacent cylinders to the optimal value, thereby realizing the differential expansion control of the multi-cylinder steam turbine.

[0060] The intelligent cylinder pushrod system consists of pushrod assemblies and a control system. The pushrod assemblies connect adjacent cylinders, and their axial length can be adjusted in real time according to the dynamic-static clearance adjustment needs. This ensures that the clearances between rotating and stationary parts of the turbine are at their optimal values. The adjustment commands come from the intelligent dynamic-static clearance evaluation system. After the adjustable pushrod executes the command, the system evaluates and adjusts the execution effect. The intelligent cylinder pushrod system typically adopts a double pushrod structure, with the pushrod shafts parallel to and symmetrically arranged on both sides of the cylinder.

[0061] The two ends of the push rod assembly can be supported on the outer cylinder or inner cylinder of the adjacent cylinder respectively, pushing the outer cylinder to move, the inner cylinder to move, or the inner and outer cylinders to move simultaneously.

[0062] In this embodiment, the push rod in the push rod assembly can be a thermally expanding push rod, a hydraulic push rod, an electric push rod, an electrically heated push rod, or other push rods with high thrust and small displacement adjustable.

[0063] Reference Figure 4 When a thermally expanding push rod is selected, the push rod assembly includes push rod connectors 11, a thermally expanding push rod 12, an insulation layer 13, a fluid inlet 14, a reinforced heat exchange element 15, and a fluid outlet 16. The two push rod connectors 11 at both ends of the thermally expanding push rod 12 are connected to the cylinder. When the push rod 12 needs to extend, a hot fluid with a temperature higher than that of the push rod 12 is introduced through the fluid inlet 14. With the assistance of the reinforced heat exchange element 15, the push rod 12 is rapidly heated, causing it to thermally expand. The fluid after heat exchange is discharged from the fluid outlet 16. When the push rod 12 needs to contract, a cold fluid with a temperature lower than that of the push rod 12 is introduced through the fluid inlet 14. With the assistance of the reinforced heat exchange element 15, the push rod 12 is rapidly cooled, causing it to coldly contract. The fluid after heat exchange is discharged from the fluid outlet 16.

[0064] Specifically, the hot fluid and cold fluid can be steam, water, heat transfer oil, etc.

[0065] Specifically, attached Figure 4 The thermal expansion push rod shown is not a specific structure of the thermal expansion push rod, but only a schematic diagram of the thermal expansion push rod. Any method that changes the length of the push rod without being separated from the thermal expansion and contraction caused by the cooling / heating of the cold / hot fluid is an equivalent implementation of this embodiment.

[0066] Reference Figure 5When the hydraulic push rod is selected, the push rod assembly includes a push rod piston connecting piece 17, a hydraulic push rod 18, a first fluid interface 19 and a second fluid interface 20. The left side of the hydraulic push rod 18 is connected with the cylinder through the push rod piston connecting piece 17, and the right side is directly connected with the cylinder. When the adjustable push rod needs to be elongated, high-pressure liquid is discharged from the first fluid interface 19 and supplemented from the second fluid interface 20 at the same time, so that the push rod piston connecting piece 17 moves to the left. When the adjustable push rod needs to be shortened, high-pressure liquid is supplemented from the first fluid interface 19 and discharged from the second fluid interface 20 at the same time, so that the push rod piston connecting piece 17 moves to the right.

[0067] Specifically, the hydraulic push rod shown is not a specific structure of the hydraulic push rod, but only a schematic diagram of the hydraulic push rod, and any method for changing the length of the push rod without hydraulic action is an equivalent implementation of the embodiment. Figure 5 The hydraulic push rod shown is not a specific structure of the hydraulic push rod, but only a schematic diagram of the hydraulic push rod, and any method for changing the length of the push rod without hydraulic action is an equivalent implementation of the embodiment.

[0068] The expansion difference intelligent control system for the multi-cylinder steam turbine rapid start-stop provided by the application is based on real-time monitoring results of cylinder temperature distribution and real-time monitoring results of expansion difference between each cylinder and the rotor, and comprehensively evaluates real-time dynamic-static gap, safety margin and adjustable range at each position of the static part and the rotating part of the steam turbine, and then adjusts the axial distance between adjacent cylinders to the optimal value through the extension and contraction of the adjustable push rod, so as to avoid dynamic-static rubbing problems in the process of steam turbine rapid start-stop and variable load. The expansion difference intelligent control system provided by the application overcomes the dynamic-static rubbing problems that may be caused by the natural thermal expansion difference between the cylinder and the rotor in the process of steam turbine start-stop and rapid variable load through intelligent evaluation and active adjustment method, and can realize high-speed and high-load rapid warm-up of the steam turbine, and significantly improves the start-stop and variable load speed of the steam turbine.

[0069] Based on the same concept, the application further provides a steam turbine expansion difference control device, which comprises an acquisition module, an obtaining module, a determining module, an evaluation module and a control module.

[0070] The acquisition module is used for acquiring the temperature on the axial direction of each cylinder in the multi-cylinder steam turbine and the expansion difference between the cylinder and the corresponding rotor, and determining the cylinder axial thermal expansion distribution curve according to the temperature on the axial direction of each cylinder.

[0071] The obtaining module is used for obtaining the total rotor axial thermal expansion based on the cylinder axial thermal expansion distribution curve and the expansion difference between the cylinder and the corresponding rotor, and obtaining the rotor axial thermal expansion distribution curve based on the rotor axial thermal expansion model and the total rotor axial thermal expansion.

[0072] The determining module is used for determining the real-time dynamic-static gap at each position of the static part and the rotating part of the multi-cylinder steam turbine according to the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve and the relative reference position of the cylinder and the rotor.

[0073] The evaluation module is used for evaluating the real-time dynamic static gap, and determining the optimal displacement amount of the push rod according to the evaluation result, the push rod being used for connecting adjacent cylinders.

[0074] The control module is used for controlling the push rod assembly to move the distance between the adjacent cylinders to the optimal value based on the optimal displacement amount of the push rod, so as to realize the differential expansion control of the multi-cylinder steam turbine.

[0075] The application further provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor realizes the steam turbine differential expansion control method when executing the program.

[0076] The application further provides a computer readable storage medium, which stores the computer program, and the computer program realizes the steam turbine differential expansion control method when executed by the processor.

[0077] Although the preferred embodiments of the application have been described, those skilled in the art can make additional changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the application.

[0078] Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application fall within the scope of the claims of the application and equivalent technologies, the application is also intended to include these modifications and variations.

Claims

1. A method for controlling differential expansion in a multi-cylinder steam turbine, characterized in that, Includes the following steps: The axial temperature of each cylinder in a multi-cylinder steam turbine and the expansion difference between the cylinder and the corresponding rotor are collected in real time, and the axial thermal expansion distribution curve of the cylinder is determined based on the axial temperature of each cylinder. By combining the cylinder axial thermal expansion distribution curve and the expansion difference value with the corresponding rotor, the total axial thermal expansion of the rotor is obtained. Based on the rotor axial thermal expansion model, the rotor axial thermal expansion distribution curve is obtained according to the total rotor axial thermal expansion. Based on the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve, and the relative reference positions of the cylinder and rotor, the real-time dynamic and static clearances at various points of the stationary and rotating components of the multi-cylinder steam turbine are determined. The real-time dynamic and static clearances are evaluated, and the optimal displacement of the push rod is determined based on the evaluation results. The push rod is used to connect adjacent cylinders. Based on the optimal displacement of the pushrod, the pushrod assembly is controlled to move the distance between adjacent cylinders to the optimal value, thereby achieving differential expansion control of the multi-cylinder turbine.

2. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 1, characterized in that, The multi-cylinder steam turbine refers to a steam turbine for thermal power generation, nuclear power generation, solar thermal power generation, and gas-steam combined cycle, which includes 2-6 cylinders. The axial temperature of each cylinder in the steam turbine is monitored by multiple temperature sensors, the expansion difference value between each cylinder and the corresponding rotor is monitored by expansion difference sensors, and the monitored temperature and expansion difference value are collected in real time by a data acquisition system.

3. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 1, characterized in that, The rotor axial thermal expansion model is a model relating the rotor axial thermal expansion distribution characteristics, the total rotor axial thermal expansion, and the inlet steam temperature, and is determined through three-dimensional numerical simulation.

4. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 1, characterized in that, The process of evaluating the real-time dynamic and static clearance and determining the optimal displacement of the push rod based on the evaluation results includes the following steps: Evaluate the safety margin of dynamic and static clearances based on design parameters and empirical data; Stress and thrust analysis was performed on the cylinder connecting pipes to determine the adjustable amount of cylinder axial displacement. The optimal displacement of the push rod is obtained based on the safety margin of the dynamic and static clearance and the adjustable amount of the cylinder axial displacement.

5. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 1, characterized in that, The push rod is supported at both ends on the outer or inner cylinder of the adjacent cylinder, respectively, and pushes the outer cylinder to move, the inner cylinder to move, or the inner and outer cylinders to move simultaneously; the push rod is one of the following: thermal expansion push rod, hydraulic push rod, electric push rod, electric heating push rod, and other push rods with large thrust and small displacement adjustable.

6. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 5, characterized in that, When a thermal expansion push rod is selected, the push rod assembly includes a thermal expansion push rod (12), the two ends of which are connected to the cylinder through push rod connectors (11), and an enhanced heat exchange element (15) is provided inside; a fluid inlet (14) is provided through the outer side of one end of the thermal expansion push rod (12), and a fluid outlet (16) is provided through the outer side of the other end; an insulation layer (13) is sleeved on the outer side of the thermal expansion push rod (12); When the thermal expansion push rod (12) needs to be extended, a hot fluid with a temperature higher than that of the thermal expansion push rod (12) is introduced from the fluid inlet (14). With the assistance of the enhanced heat exchange element (15), the thermal expansion push rod (12) is rapidly heated, causing the thermal expansion push rod (12) to thermally expand. The fluid after heat exchange is discharged from the fluid outlet (16). When the thermal expansion push rod (12) needs to contract, a cold fluid with a temperature lower than that of the thermal expansion push rod (12) is introduced from the fluid inlet (14). With the assistance of the enhanced heat exchange element (15), the thermal expansion push rod (12) is rapidly cooled, causing it to contract. The fluid after heat exchange is discharged from the fluid outlet (16).

7. The method for controlling the differential expansion of a multi-cylinder steam turbine as described in claim 5, characterized in that, When a hydraulic push rod is selected, the push rod assembly includes a hydraulic push rod (18), one end of which is connected to the cylinder through a push rod piston connector (17), and the other end is directly connected to the cylinder; a first fluid interface (19) is provided through the outer side of one end of the hydraulic push rod (18), and a second fluid interface (20) is provided through the outer side of the other end; When the hydraulic push rod (18) needs to extend, high-pressure liquid is discharged from the first fluid interface (19) and high-pressure liquid is replenished from the second fluid interface (20), causing the push rod piston connector (17) to move outward; When the hydraulic push rod (18) needs to be shortened, high-pressure liquid is supplied from the first fluid interface (19) and high-pressure liquid is discharged from the second fluid interface (20), causing the push rod piston connector (17) to move inward.

8. A steam turbine differential expansion control device, characterized in that, include: The data acquisition module is used to acquire the axial temperature of each cylinder in the multi-cylinder turbine and the expansion difference between the cylinder and the corresponding rotor in real time, and to determine the axial thermal expansion distribution curve of the cylinder based on the axial temperature of each cylinder. The acquisition module is used to combine the cylinder axial thermal expansion distribution curve and the expansion difference value with the corresponding rotor to obtain the total axial thermal expansion of the rotor. Based on the rotor axial thermal expansion model, the rotor axial thermal expansion distribution curve is obtained according to the total rotor axial thermal expansion. The determination module is used to determine the real-time dynamic and static clearances at various points of stationary and rotating components of a multi-cylinder steam turbine based on the cylinder axial thermal expansion distribution curve, the rotor axial thermal expansion distribution curve, and the relative reference positions of the cylinder and rotor. An evaluation module is used to evaluate the real-time dynamic and static clearances and determine the optimal displacement of the push rod based on the evaluation results. The push rod is used to connect adjacent cylinders. The control module is used to control the push rod assembly to move the distance between adjacent cylinders to the optimal value based on the optimal displacement of the push rod, thereby realizing the differential expansion regulation of the multi-cylinder steam turbine.

9. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the turbine differential expansion control method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the turbine differential expansion control method according to any one of claims 1-7.

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