Method for measuring and calculating through-flow efficiency characteristics of a turbine control stage and terminal device

Abstract

The present application relates to a kind of steam turbine governing stage flow efficiency characteristics measurement and calculation method, comprising the following steps, S1, the governing stage flow efficiency of calculating VWO design condition, governing stage design pressure ratio, governing stage volume flow;S2, the governing stage pressure ratio of calculating accounting condition, the governing stage flow ratio and the governing stage volume flow ratio of accounting condition relative to VWO design condition, the governing stage ideal enthalpy drop ratio of accounting condition relative to VWO design condition, the governing stage outlet velocity ratio, the governing stage relative speed ratio and the governing stage speed ratio of accounting condition;S3, the relative governing stage flow efficiency of calculating accounting condition and the governing stage flow efficiency of accounting condition;S4, the governing stage rear pressure of multiple accounting conditions is reset, finally obtains the characteristic relationship of governing stage pressure ratio and governing stage flow efficiency and the characteristic relationship of governing stage volume flow and governing stage efficiency.The present application can conveniently measure and calculate the governing stage flow efficiency changed with governing stage pressure ratio and volume flow.

Description

Technical Field

[0001] This invention belongs to the field of energy-saving and economical operation technology of thermal power units, specifically relating to a method for calculating the flow efficiency characteristics of the regulating stage of a steam turbine and a terminal device. Background Technology

[0002] With the increase in the grid connection capacity of new energy sources, thermal power units will gradually transform from traditional power generation sources to regulation-type power sources, and the operational flexibility, including peak-shaving performance, of thermal power units has received increasing attention. This has led to the economic efficiency of thermal power units during peak shaving becoming a focus for power plants.

[0003] A steam turbine is a device that uses steam to drive a generator and produce electricity; it is one of the three main pieces of equipment in a power plant. A nozzle and a blade array constitute a basic structural component of a steam turbine—a stage. Many stages form a multi-stage steam turbine. The first stage of a steam turbine is usually called the regulating stage, also known as the velocity stage. Structurally, it is typically larger in diameter than other pressure stages. The flow area of ​​the regulating stage can be adjusted according to load changes, thus achieving a regulating effect; hence, it is called the regulating stage. Since the steam ejected from the regulating stage nozzles is depressurized and cooled from the main steam, it has a very high velocity. To a large extent, the work done by the steam on the regulating stage impeller is achieved through the impact of this very high steam velocity.

[0004] Currently, the heat loss rates of domestically produced steam turbines are generally high, some exceeding design values ​​and even surpassing the manufacturer's guaranteed values ​​(typically 3% higher than design values). This is primarily due to the generally low efficiency of the regulating stage. The actual efficiency of the steam turbine regulating stage exhibits complex characteristics under different constant-pressure and sliding-pressure operating modes, and accurately obtaining these characteristics has long been a challenge for on-site engineering technicians. Understanding the efficiency variation characteristics of the steam turbine regulating stage with different operating modes is crucial for determining the most economical constant-pressure and sliding-pressure operating modes for the unit.

[0005] Chinese Patent Application No. 202210227288.0 discloses a dual-regulating stage steam turbine unit and its operation method, including the following steps: S1, determining the load switching point Lx; S2, collecting the current operating load at detection time intervals; S3, if the current operating load is greater than or equal to Lx, determining the opening status of the first regulating valve assembly and the second regulating valve assembly, and adjusting them to a state where the first regulating valve assembly is partially closed and the second regulating valve assembly is open; S4, if the current operating load is less than Lx, determining the opening status of the first regulating valve assembly and the second regulating valve assembly, and adjusting them to a state where the second regulating valve assembly is partially closed, the first regulating valve assembly is open, and the third regulating valve assembly is open. Chinese Patent Application No. 201710109546.4 discloses a diagnostic method for abnormal flow stage efficiency in a steam turbine high-pressure cylinder. The research content of this method is: how to diagnose the cause of abnormal high-pressure cylinder flow parameters. The present invention proposes the following approach: First, the impact of changes in inlet steam temperature on the efficiency of the high-pressure cylinder flow stage is tested. Based on the linear expansion trend of steam within the turbine stage, it is determined whether steam leakage exists inside the high-pressure cylinder. Then, the electric valves for steam extraction at each stage of the high-pressure cylinder are closed, and the pressure and temperature of the inlet, outlet, and extraction stages are measured. The ratio of extraction pressure to downstream flow rate is calculated under varying operating conditions. The difference between the extraction pressure and the corresponding downstream pressure is compared to ultimately determine the cause of the abnormal high-pressure cylinder flow stage efficiency. In existing technologies, the methods for calculating the flow efficiency characteristics of the turbine regulating stage during economic turbine operation are generally complex and computationally intensive. There is a need to develop a convenient method for calculating the flow efficiency of the regulating stage as the regulating stage pressure ratio and volumetric flow rate change, providing an analytical basis for determining the optimal operating mode of the unit. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a method and terminal equipment for calculating the flow efficiency characteristics of the regulating stage of a steam turbine. This method can conveniently calculate the flow efficiency of the regulating stage as the regulating stage pressure ratio and volumetric flow rate change, providing an analytical basis for determining the optimal operating mode of the unit.

[0007] The technical solution adopted in this invention is: This invention provides a method for calculating the flow efficiency characteristics of a steam turbine regulating stage, comprising the following steps: S1, obtain the design parameters of the steam turbine under the VWO design condition, and calculate the regulating stage flow efficiency, regulating stage design pressure ratio, and regulating stage volumetric flow rate under the VWO design condition; S2, set the regulating stage pressure for the calculation condition, calculate the regulating stage pressure ratio for the calculation condition, the regulating stage flow ratio and the regulating stage volumetric flow ratio for the calculation condition relative to the VWO design condition, calculate the ideal enthalpy drop ratio and the regulating stage outlet velocity ratio, the regulating stage relative velocity ratio, and the regulating stage velocity ratio for the calculation condition relative to the VWO design condition. S3, calculate the relative regulating stage flow efficiency and the regulating stage flow efficiency under the accounting conditions; S4. Reset the pressure after the regulating stage for multiple calculation conditions, calculate the regulating stage flow efficiency corresponding to each regulating stage pressure, and finally obtain the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency, as well as the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage efficiency.

[0008] Further, in step S1, the design parameters under the VWO design condition include main steam pressure, main steam temperature, main steam flow rate, design pressure loss of the shut-off valve, design pressure loss of the regulating valve, number of regulating valves, pressure after the regulating stage, and temperature after the regulating stage. Further, in step S2, the processes for calculating the regulating stage pressure ratio of the verification condition, the regulating stage flow rate ratio of the verification condition relative to the VWO design condition, and the regulating stage volumetric flow rate ratio are as follows: The formula for calculating the regulating stage pressure ratio under the calculation condition is: ε cs =p2 / p 0d ′ In the above formula, p′ 0d For the pre-regulating stage pressure under VWO design conditions, p′ 0d =p msd ×(1-ΔP sv )×(1-ΔP cv ), p msd ΔP sv ΔP cv These represent the main steam pressure, shut-off valve design pressure loss, and regulating valve design pressure loss under VWO design conditions; ε cs To calculate the regulating stage pressure ratio for the operating condition, p2 is the regulating stage pressure after the operating condition. The formula for calculating the regulating stage flow ratio of the accounting operating condition relative to the VWO design operating condition is as follows:

[0009] In the formula, p 2d For the pressure after the regulating stage under VWO design conditions; R f To calculate the regulating stage flow ratio relative to the VWO design operating condition.

[0010] The formula for calculating the regulating stage volumetric flow ratio relative to the VWO design operating condition is: R vf =R f In the formula, R vf To calculate the volumetric flow ratio of the regulating stage relative to the VWO design operating condition.

[0011] The formula for calculating the volumetric flow rate of the regulating stage under the accounting condition is as follows: Vf cs =Vf csd ×Rvf In the formula, Vf cs For calculating the regulating stage volumetric flow rate under operating conditions; Vf csd The volumetric flow rate of the regulating stage under VWO design conditions.

[0012] Further, in step S2, the method for calculating the ideal enthalpy drop ratio of the regulating stage, the outlet velocity ratio of the regulating stage, the relative velocity ratio of the regulating stage, and the velocity ratio of the regulating stage under the calculation condition relative to the VWO design condition is as follows: The formula for calculating the ideal enthalpy drop ratio of the regulating stage relative to the VWO design condition is as follows:

[0013] Among them, R ΔH ε represents the ideal enthalpy drop ratio of the adjustment stage relative to the VWO design condition under the calculated operating condition. cs ε represents the regulating stage pressure ratio for the accounting operating condition. csd Indicates the regulating stage pressure ratio under VWO design conditions; The following formula is used to calculate the ratio of the regulating stage outlet velocity to the VWO design velocity under the calculation condition:

[0014] In the formula, R v0 To calculate the ratio of the regulating stage outlet velocity to the VWO design operating condition; The following formula is used to calculate the relative speed ratio of the regulating stage relative to the VWO design condition under the calculation condition: R u / v0 =1 / R v0 In the formula, R u / v0 To calculate the relative speed ratio of the regulating stage relative to the VWO design operating condition; The speed ratio of the regulating stage in the calculation condition is The calculation formula is:

[0015] Furthermore, the calculation process for step S3 is as follows: The formula for calculating the relative regulating stage flow efficiency under the accounting conditions is:

[0016] In the formula, R ηcs To calculate the relative regulating stage flow efficiency under operating conditions; The regulating stage flow efficiency under the calculation condition is calculated using the following formula: η cs =R ηcs ×η cs D In the formula, η cs To calculate the regulating stage flow efficiency under operating conditions; η cs D The flow efficiency of the regulating stage under VWO design conditions.

[0017] Further, in step S1, the regulating stage flow efficiency under the VWO design conditions is calculated using the following steps: 1) Calculate the temperature before the regulating stage under VWO design conditions using the following formula: t′ 0d =tph(p′) 0d ,hpt(p msd , t msd )) Where, p msd , t msd p′ represents the main steam pressure and main steam temperature under the VWO design conditions, respectively. 0d The pressure before the regulating stage under VWO design conditions; hpt(p, t) represents the steam-water characteristic function for solving the enthalpy of the medium based on the medium pressure and medium temperature, and tph(p, h) represents the steam-water characteristic function for solving the medium temperature based on the medium pressure and medium enthalpy. 2) Calculate the ideal enthalpy drop corresponding to the pressure after the regulating stage using the formula: ΔH is =hpt(p′) 0d ,t′ 0d )-hps(p 2d ,spt(p′ 0d ,t′ 0d )) Where, ΔH is p represents the ideal enthalpy drop corresponding to the pressure after the regulating stage. 2d represents the pressure after the regulating stage under VWO design conditions; spt(p, t) represents the steam-water characteristic function that solves the entropy value of the medium based on the medium pressure and medium temperature; hps(p, s) represents the steam-water characteristic function that solves the enthalpy value of the medium based on the medium pressure and medium entropy value. 3) The regulating stage flow efficiency under VWO design conditions is calculated using the following formula:

[0018] Among them, t 2d This indicates the temperature after the regulating stage under VWO design conditions; Calculate the design pressure ratio ε of the regulating stage csd Regulating stage volumetric flow rate Vf csd The formula is: ε csd =p 2d / p Qd ′ Vf csd =F msd ×svpt(p 0d , t 0d ) In the formula, F msd is the main steam flow rate under VWO design conditions; svpt(p,t) represents the steam-water characteristic function calculated based on the medium pressure and medium temperature to determine the specific volume of the medium.

[0019] Furthermore, in step S4, the method for obtaining the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency is as follows: By performing curve fitting on the regulating stage pressure and regulating stage flow efficiency data obtained from multiple calculation conditions, a functional expression for the regulating stage flow efficiency as a function of the regulating stage pressure ratio is obtained.

[0020] Furthermore, in step S4, the method for obtaining the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage efficiency is as follows: By performing curve fitting on the regulating stage volumetric flow rate and regulating stage flow efficiency data obtained from multiple calculation conditions, a functional expression for the regulating stage flow efficiency as a function of the regulating stage volumetric flow rate is obtained.

[0021] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the methods described above.

[0022] The present invention also provides a device for measuring the flow efficiency characteristics of a turbine regulating stage, comprising a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the corresponding steps in any of the above methods.

[0023] The beneficial effects of this invention are as follows: Traditional methods for measuring the flow efficiency characteristics of a turbine regulating stage require detailed calculations of the regulating stage under varying operating conditions, necessitating detailed flow stage parameters that are often difficult to obtain at power plant sites. This invention provides a simplified method for calculating the flow efficiency characteristics of a turbine regulating stage, enabling convenient calculation of the regulating stage flow efficiency as the regulating stage pressure ratio and volumetric flow rate change, thus providing an analytical basis for determining the optimal operating mode of the unit. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the calculation method of the present invention. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0029] In this invention, the VWO design condition is the valve fully open design condition.

[0030] Reference Figure 1 This invention provides a method for calculating the flow efficiency characteristics of a turbine regulating stage, comprising the following steps: S1, obtain the design parameters of the steam turbine under the VWO design condition, and calculate the regulating stage flow efficiency, regulating stage design pressure ratio, and regulating stage volumetric flow rate under the VWO design condition; In step S1, the design parameters under the VWO design conditions include main steam pressure, main steam temperature, main steam flow rate, design pressure loss of the shut-off valve, design pressure loss of the regulating valve, number of regulating valves, pressure after the regulating stage, and temperature after the regulating stage.

[0031] In step S1, the regulating stage flow efficiency under the VWO design conditions is calculated using the following steps: 1) Calculate the temperature before the regulating stage under VWO design conditions using the following formula: t′ 0d =tph(p′) 0d ,hpt(p msd , t msd )) Where, p msd , t msd p′ represents the main steam pressure and main steam temperature under the VWO design conditions, respectively. 0d The pressure before the regulating stage under VWO design conditions; hpt(p, t) represents the steam-water characteristic function for solving the enthalpy of the medium based on the medium pressure and medium temperature, and tph(p, h) represents the steam-water characteristic function for solving the medium temperature based on the medium pressure and medium enthalpy. 2) Calculate the ideal enthalpy drop corresponding to the pressure after the regulating stage using the formula: ΔH is =hpt(p 0d , t 0d )-hps(p 2d ,spt(p 0d , t 0d )) Where, ΔH is p represents the ideal enthalpy drop corresponding to the pressure after the regulating stage. 2d represents the pressure after the regulating stage under VWO design conditions; spt(p, t) represents the steam-water characteristic function that solves the entropy value of the medium based on the medium pressure and medium temperature; hps(p, s) represents the steam-water characteristic function that solves the enthalpy value of the medium based on the medium pressure and medium entropy value. 3) The regulating stage flow efficiency under VWO design conditions is calculated using the following formula:

[0032] Among them, t 2d This indicates the temperature after the regulating stage under VWO design conditions; Calculate the design pressure ratio ε of the regulating stage csd Regulating stage volumetric flow rate Vf csd The formula is: ε csd =p 2d / p 0d ′ Vf csd =F msd ×svpt(p′ 0d ,t′ 0d ) In the formula, F msdis the main steam flow rate under VWO design conditions; svpt(p,t) represents the steam-water characteristic function calculated based on the medium pressure and medium temperature to determine the specific volume of the medium.

[0033] S2, set the regulating stage pressure for the calculation condition, calculate the regulating stage pressure ratio for the calculation condition, the regulating stage flow ratio and the regulating stage volumetric flow ratio for the calculation condition relative to the VWO design condition, calculate the ideal enthalpy drop ratio and the regulating stage outlet velocity ratio, the regulating stage relative velocity ratio, and the regulating stage velocity ratio for the calculation condition relative to the VWO design condition. In step S2, the processes for calculating the regulating stage pressure ratio, the regulating stage flow ratio relative to the VWO design condition, and the regulating stage volumetric flow ratio are as follows: The formula for calculating the regulating stage pressure ratio under the calculation condition is: ε cs =p2 / p 0d ′ In the above formula, p′ 0d For the pre-regulating stage pressure under VWO design conditions, p′ 0d =p msd ×(1-ΔP sv )×(1-ΔP cv ), p msd ΔP sv ΔP cv These represent the main steam pressure, shut-off valve design pressure loss, and regulating valve design pressure loss under VWO design conditions; ε cs To calculate the regulating stage pressure ratio for the operating condition, p2 is the regulating stage pressure after the operating condition. The formula for calculating the regulating stage flow ratio of the accounting operating condition relative to the VWO design operating condition is as follows:

[0034] In the formula, p 2d For the pressure after the regulating stage under VWO design conditions; R f To calculate the regulating stage flow ratio relative to the VWO design operating condition.

[0035] The formula for calculating the regulating stage volumetric flow ratio relative to the VWO design operating condition is: R vf =R f In the formula, R vf To calculate the volumetric flow ratio of the regulating stage relative to the VWO design operating condition.

[0036] The formula for calculating the volumetric flow rate of the regulating stage under the accounting condition is as follows: Vf cs =Vf csd ×R vf In the formula, Vfcs For calculating the regulating stage volumetric flow rate under operating conditions; Vf csd The volumetric flow rate of the regulating stage under VWO design conditions.

[0037] In step S2, the method for calculating the ideal enthalpy drop ratio of the regulating stage, the outlet velocity ratio of the regulating stage, the relative velocity ratio of the regulating stage, and the velocity ratio of the regulating stage under the calculation condition relative to the VWO design condition is as follows: The formula for calculating the ideal enthalpy drop ratio of the regulating stage relative to the VWO design condition is as follows:

[0038] Among them, R ΔH ε represents the ideal enthalpy drop ratio of the adjustment stage relative to the VWO design condition under the calculated operating condition. cs ε represents the regulating stage pressure ratio for the accounting operating condition. csd Indicates the regulating stage pressure ratio under VWO design conditions; The following formula is used to calculate the ratio of the regulating stage outlet velocity to the VWO design velocity under the calculation condition:

[0039] In the formula, R v0 To calculate the ratio of the regulating stage outlet velocity to the VWO design operating condition; The following formula is used to calculate the relative speed ratio of the regulating stage relative to the VWO design condition under the calculation condition: R u / v0 =1 / R v0 In the formula, R u / v0 To calculate the relative speed ratio of the regulating stage relative to the VWO design operating condition; The speed ratio of the regulating stage in the calculation condition is The calculation formula is:

[0040] S3, calculate the relative regulating stage flow efficiency and the regulating stage flow efficiency under the accounting conditions; The calculation process for step S3 is as follows: The formula for calculating the relative regulating stage flow efficiency under the accounting conditions is:

[0041] In the formula, R ηcs To calculate the relative regulating stage flow efficiency under operating conditions; The regulating stage flow efficiency under the calculation condition is calculated using the following formula: η cs =R ηcs ×η cs D In the formula, η cs To calculate the regulating stage flow efficiency under operating conditions; η cs D The flow efficiency of the regulating stage under VWO design conditions.

[0042] S4. Reset the pressure after the regulating stage for multiple calculation conditions, calculate the regulating stage flow efficiency corresponding to each regulating stage pressure, and finally obtain the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency, as well as the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage efficiency.

[0043] In step S4, the method for obtaining the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency is as follows: By performing curve fitting on the pressure and flow efficiency data of the regulating stage obtained from multiple calculation conditions, a functional expression of the flow efficiency of the regulating stage as a function of the regulating stage pressure ratio is obtained.

[0044] In step S4, the method for obtaining the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage efficiency is as follows: By performing curve fitting on the regulating stage volumetric flow rate and regulating stage flow efficiency data obtained from multiple calculation conditions, a functional expression for the regulating stage flow efficiency as a function of the regulating stage volumetric flow rate is obtained.

[0045] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the above method when executing the computer program.

[0046] This invention also provides a device for measuring the flow efficiency characteristics of a turbine regulating stage, comprising a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the corresponding steps described above. The above-described embodiments are preferred embodiments of this invention, but not exhaustive examples of all possible implementations. For those skilled in the art, various modifications made without departing from the spirit and essence of this invention should be considered within the scope of protection of this invention.

Claims

1. A method for calculating the flow efficiency characteristics of a turbine regulating stage, characterized in that, The process includes the following steps: S1, obtaining the design parameters of the turbine under the VWO design condition, and calculating the regulating stage flow efficiency, regulating stage design pressure ratio, and regulating stage volumetric flow rate under the VWO design condition; S2, set the regulating stage pressure for the calculation condition, calculate the regulating stage pressure ratio for the calculation condition, the regulating stage flow ratio and the regulating stage volumetric flow ratio for the calculation condition relative to the VWO design condition, calculate the ideal enthalpy drop ratio and the regulating stage outlet velocity ratio, the regulating stage relative velocity ratio, and the regulating stage velocity ratio for the calculation condition relative to the VWO design condition. S3, calculate the relative regulating stage flow efficiency and the regulating stage flow efficiency under the accounting conditions; S4. Reset the pressure after the regulating stage for multiple calculation conditions, calculate the regulating stage flow efficiency corresponding to each regulating stage pressure, and finally obtain the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency, as well as the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage flow efficiency.

2. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 1, characterized in that, In step S1, the design parameters under the VWO design conditions include main steam pressure, main steam temperature, main steam flow rate, design pressure loss of the shut-off valve, design pressure loss of the regulating valve, number of regulating valves, pressure after the regulating stage, and temperature after the regulating stage.

3. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 1, characterized in that, In step S2, the processes for calculating the regulating stage pressure ratio, the regulating stage flow ratio relative to the VWO design condition, and the regulating stage volumetric flow ratio are as follows: The formula for calculating the regulating stage pressure ratio under the calculation condition is: ε cs =p2 / p 0d ' In the above formula, p' 0d For the pre-regulating stage pressure under VWO design conditions, p' 0d =p msd ×(1-ΔP sv )×(1-ΔP cv ), p msd ΔP sv ΔP cv These represent the main steam pressure, shut-off valve design pressure loss, and regulating valve design pressure loss under VWO design conditions; ε cs To calculate the regulating stage pressure ratio for the operating condition, p2 is the regulating stage pressure after the operating condition. The formula for calculating the regulating stage flow ratio of the accounting operating condition relative to the VWO design operating condition is as follows: ； In the formula, p 2d For the pressure after the regulating stage under VWO design conditions; R f To calculate the regulating stage flow ratio relative to the VWO design operating condition; The formula for calculating the regulating stage volumetric flow ratio relative to the VWO design operating condition is: R vf =R f In the formula, R vf To calculate the regulating stage volumetric flow rate ratio relative to the VWO design operating condition; The formula for calculating the volumetric flow rate of the regulating stage under the accounting condition is as follows: Vf cs =Vf csd ×R vf In the formula, Vf cs To calculate the volumetric flow rate of the regulating stage under operating conditions; Vf csd The volumetric flow rate of the regulating stage under VWO design conditions.

4. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 1, characterized in that, In step S2, the method for calculating the ideal enthalpy drop ratio of the regulating stage, the outlet velocity ratio of the regulating stage, the relative velocity ratio of the regulating stage, and the velocity ratio of the regulating stage under the calculation condition relative to the VWO design condition is as follows: The formula for calculating the ideal enthalpy drop ratio of the regulating stage relative to the VWO design condition is as follows: ; Among them, R ΔH ε represents the ideal enthalpy drop ratio of the adjustment stage relative to the VWO design condition under the calculated operating condition. cs ε represents the regulating stage pressure ratio for the accounting operating condition. csd Indicates the regulating stage pressure ratio under VWO design conditions; The following formula is used to calculate the ratio of the regulating stage outlet velocity to the VWO design velocity under the calculation condition: ； In the formula, R v0 To calculate the ratio of the regulating stage outlet velocity to the VWO design operating condition; The relative speed ratio of the regulating stage to the VWO design condition is calculated using the following formula: R u / v0 =1 / R v0 In the formula, R u / v0 To calculate the relative speed ratio of the regulating stage relative to the VWO design operating condition; The speed ratio of the regulating stage in the calculation condition is The calculation formula is:

5. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 4, characterized in that, The calculation process for step S3 is as follows: The formula for calculating the relative regulating stage flow efficiency under the accounting conditions is: ； In the formula, R ηcs To calculate the relative regulating stage flow efficiency under operating conditions; The regulating stage flow efficiency under the calculation condition is calculated using the following formula: η cs =R ηcs ×η cs D In the formula, η cs To calculate the flow efficiency of the regulating stage under operating conditions; η cs D The flow efficiency of the regulating stage under VWO design conditions.

6. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 1, characterized in that, In step S1, the regulating stage flow efficiency under the VWO design conditions is calculated using the following steps: 1) Calculate the temperature before the regulating stage under VWO design conditions using the formula: t' 0d =tph(p' 0d ,hpt(p msd , t msd )) Where, p msd , t msd These represent the main steam pressure and main steam temperature under the VWO design conditions, respectively; p' 0d Lowering the design load for VWO The pressure before the stage; hpt(p,t) represents the steam-water characteristic function that calculates the enthalpy of the medium based on the medium pressure and medium temperature, and tph(p,h) represents the steam-water characteristic function that calculates the medium temperature based on the medium pressure and medium enthalpy. 2) Calculate the ideal enthalpy drop corresponding to the pressure after the regulating stage using the formula: ΔH is =hpt(p′) 0d ,t′ 0d )-hps(p 2d ,spt(p′ 0d ,t′ 0d )) Where, ΔH is p represents the ideal enthalpy drop corresponding to the pressure after the regulating stage. 2d This indicates the pressure after the regulating stage under VWO design conditions; spt(p,t) represents the steam-water characteristic function that calculates the entropy of the medium based on the medium pressure and medium temperature, and hps(p,s) represents the steam-water characteristic function that calculates the enthalpy of the medium based on the medium pressure and medium entropy. 3) The regulating stage flow efficiency under VWO design conditions is calculated using the following formula: ； Among them, t 2d This indicates the temperature after the regulating stage under VWO design conditions; Calculate the design pressure ratio ε of the regulating stage csd Regulating stage volumetric flow rate Vf csd The formula is: e csd =p 2d / p 0d ' Vf csd =F msd ×svpt(p′ 0d ,t′ 0d ) In the formula, F msd svpt(p,t) represents the main steam flow rate under VWO design conditions; svpt(p,t) represents the steam-water characteristic function calculated based on the medium pressure and medium temperature to determine the specific volume of the medium.

7. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 6, characterized in that, In step S4, the method for obtaining the characteristic relationship between the regulating stage pressure ratio and the regulating stage flow efficiency is as follows: By performing curve fitting on the pressure and flow efficiency data of the regulating stage obtained from multiple calculation conditions, a functional expression for the flow efficiency of the regulating stage as a function of the regulating stage pressure ratio is obtained.

8. The method for calculating the flow efficiency characteristics of a turbine regulating stage according to claim 6, characterized in that, In step S4, the method for obtaining the characteristic relationship between the regulating stage volumetric flow rate and the regulating stage flow efficiency is as follows: By performing curve fitting on the regulating stage volumetric flow rate and regulating stage flow efficiency data obtained from multiple calculation conditions, a functional expression for the regulating stage flow efficiency as a function of the regulating stage volumetric flow rate is obtained.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 8.

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