Simulation method of water injection phase modulation system of hydroelectric generating set

Abstract

This invention provides a simulation method for a pressurized water phase regulation system of a hydropower unit, relating to the field of water conservancy and hydropower engineering technology. The method includes: analyzing and extracting system parameters, and establishing three modeling frameworks; constructing a turbine model within the first framework based on the water level in the runner chamber; setting different runner speeds, determining the optimal cross-sectional area of ​​the throttle valve based on Bernoulli's equation, dividing the lubrication interval according to flow rate, and establishing a mapping relationship between cross-sectional area and speed, constructing a leak-proof ring water supply system model within the second framework; establishing the relationship between water level and leakage time and flow rate, and combining hydraulic and pneumatic systems to construct an air-pressurized water-liquid mixing system model within the third framework; finally, building a control system, connecting and coordinating the detection and action components of each model to achieve signal acquisition and action control. This method effectively solves the technical problems of low design reliability, poor debugging efficiency, and difficulty in fault prediction caused by the lack of a complete simulation model in existing technologies, resulting in high reliability.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a simulation method for a pressurized water phase regulation system of a hydropower unit. Background Technology

[0002] The core technology of designing and modifying pressurized water phase regulation in hydropower units lies in constructing a collaborative air-filled pressurized water system and a leak-proof ring water supply system. The working principle and simplified physical structure of this composite system are as follows: Figure 2 As shown, this figure also serves as a schematic diagram of the motion-thermal-gas-liquid mixture multiphysics model of the simulation system of this invention.

[0003] First, the pneumatic pressurized water system is the core auxiliary equipment for hydropower station units to achieve phase adjustment operation. It includes a pneumatic system and a hydraulic system that work together to play a key role.

[0004] When the hydropower unit switches to the air-pressurized water operation mode, the hydraulic system starts to operate. Hydraulic oil is delivered to the air-pressurization solenoid valve 23 via the inlet pipe 11. Controlling the air-pressurization solenoid valve 23 causes the hydraulic oil to open the air-pressurization hydraulic valve 20. At this time, the pneumatic system starts, and medium-pressure gas that meets the preset pressure of the pressurized water phase adjustment system enters the air inlet pipe 10, and then passes through the air-pressurization check valve 34 and the air-pressurization throttle valve 14 in sequence into the impeller chamber 13, causing the water level in the impeller chamber 13 to drop to the design value. Subsequently, the air-pressurization solenoid valve 23 is controlled again to close the air-pressurization hydraulic valve 20. The closed hydraulic oil flows back through the drain pipe 15, and the hydraulic system completes the air-pressurization operation in this stage.

[0005] During stable phase-shifting operation, if the water level in the runner chamber rises due to air leakage or water leakage from the sealing ring, the hydraulic system intervenes again. Hydraulic oil is delivered to the air-replenishing solenoid directional valve 22 via the inlet pipe 11, controlling the valve to open the air-replenishing hydraulic valve 19. Simultaneously, the pneumatic system performs air-replenishing operation, supplying air to the runner chamber 13 and draining water from the runner chamber 13 and tailrace pipe 29, ensuring the runner 38 rotates at high speed in the air and reducing resistance. After the air-replenishing operation is completed, the relevant hydraulic oil returns via the drain pipe 15, and the hydraulic system completes its air-replenishing auxiliary task.

[0006] When the pneumatic water pressurization operation ends, the hydraulic system and the pneumatic system work together to enter the exhaust and water return operation. Hydraulic oil is delivered to the exhaust solenoid valve 21 via the inlet pipe 11, controlling the valve to open the exhaust hydraulic valve 18. The pneumatic system then discharges the gas in the turbine chamber 13 via the exhaust pipe 12, sequentially through the exhaust electric ball valve 17 and the exhaust throttle valve 16. The water level in the turbine chamber 13 slowly rises under atmospheric pressure until it is full, while the hydraulic oil returns through the drain pipe 15. Thus, the exhaust and water return operation is complete.

[0007] Secondly, the function of the leak-proof ring water supply system is to provide sealing, lubrication, and cooling for the contact areas between the runner 38 and the upper and lower leak-proof rings 37 when the runner chamber 13 is being pressurized, thereby ensuring the safe and stable operation of the unit. Failure of the leak-proof ring water supply system could lead to a major power plant accident. Specifically, when the unit is in phase-changing operation, the runner 38 is tightly fitted with the leak-proof ring 37, and generates heat through friction with the leak-proof ring 37 during rotation. At this time, the leak-proof ring electric ball valve 30 is opened, and constant-pressure cooling water enters the leak-proof ring water supply pipeline 9, passing sequentially through the leak-proof ring check valve 32, the leak-proof ring pressure gauge 31, and the leak-proof ring electric ball valve 30, before being distributed to the upper leak-proof ring water supply pipeline 7 and the lower leak-proof ring water supply pipeline 8. Cooling water diverted to the upper leak-proof ring supply line 7 first flows through the throttle valve 28 of the upper leak-proof ring supply line 7, then through the upper leak-proof ring flow meter 26 and the upper leak-proof ring check valve 24, and finally enters the leak-proof ring 37 at the top of the impeller 38. Cooling water diverted to the lower leak-proof ring supply line 8 first flows through the throttle valve 28 on the lower leak-proof ring supply line 8, then through the lower leak-proof ring flow meter 27 and the lower leak-proof ring check valve 25, and finally enters the leak-proof ring 37 at the bottom of the impeller 38. Through this diversion path, the cooling water can achieve sealing, lubrication, and cooling of the contact area between the impeller 38 and the leak-proof ring 37.

[0008] Therefore, it is evident that the pressurized water phase regulation system of a hydropower unit is a complex system involving the collaboration of multiple systems. However, current technology lacks a simulation model that can fully simulate the operation of such a system. During the design phase, it is difficult to accurately determine the reliability of the design scheme, relying instead on historical experience and increased margins, which hinders the design and development of pressurized water phase regulation retrofits and new hydropower units. Furthermore, the on-site commissioning and maintenance of the pressurized water phase regulation system currently relies heavily on the experience and judgment of technicians. During on-site commissioning, technicians start the hydraulic system based on their accumulated experience, observing changes in parameters such as pressure and flow rate. If abnormalities occur, they can only troubleshoot potential fault points step by step, a cumbersome and inefficient process that may result in timing errors in hydraulic valves and electric ball valves, as well as insufficient hydraulic system pressure to meet on-site requirements. Moreover, the lack of accurate simulation methods makes it impossible to predict potential faults in the pressurized water phase regulation system under different phase regulation conditions, leading to high maintenance costs, prolonged equipment downtime, and impacting the normal operating efficiency of the power station. Most existing models can only simulate the static condition of the motor, and cannot fully reflect the performance and potential problems of the hydraulic system under different conditions, making it difficult to meet actual needs. Summary of the Invention

[0009] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a simulation method for the pressurized water phase regulation system of a hydropower unit. This method effectively solves the technical problems of low design reliability, poor commissioning efficiency and difficulty in fault prediction caused by the lack of a complete simulation model in the prior art. It realizes the full-condition actual simulation of the pressurized water phase regulation process of a hydropower unit, and significantly improves the reliability, commissioning efficiency and operational safety of the pressurized water phase regulation system design.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A simulation method for a hydropower unit's pressurized water phase regulation system includes the following steps: S1. Analyze and extract parameters of the pressurized water phase regulation system to be configured for the hydropower unit, and build the first framework, the second framework and the third framework; S2. Based on the water level in the runner chamber, construct turbine models under different phase adjustment conditions within the first frame; S3. Set different rotational speeds ω of the runner in the turbine model, based on the optimal flow rate of the water supply pipeline for the leak-proof ring. Using Bernoulli's equation, the optimal cross-sectional area of ​​the throttle valve orifice for different rotational speeds ω is obtained. According to the flow rate of the water supply pipeline of the leak-proof ring. The size is used to divide the contact friction state between the sealing ring and the impeller into different lubrication zones, and an optimal cross-sectional area is established based on the different lubrication zones. The mapping relationship with rotational speed ω; then, based on the mapping relationship, a leak-proof loop water supply system model adapted to different rotational speeds ω is constructed within the second framework; S4. Based on the water level in the turbine runner model, establish the relationship between water level and runner air leakage time, and the optimal flow rate of the leak-proof ring water supply pipeline. Based on the relationship, and combining the hydraulic and pneumatic systems in the pressurized water phase adjustment system, an air-pressurized water gas-liquid mixing system model is constructed within the third framework. S5. Build a control system that connects to the detection and action elements in the leak-proof ring water supply system model, to the action elements in the air-pressurized water gas-liquid mixing system model, and to the detection and action elements in the turbine model. This enables signal acquisition of the detection elements and action control of the action elements, thus completing the simulation of the pressurized water phase adjustment system.

[0011] Furthermore, in step S3, the optimal cross-sectional area The method for establishing the mapping relationship with rotational speed ω includes the following steps: S3.1, Based on flow rate The coefficient of friction is listed for different lubrication ranges. Calculate the equation; S3.2, Based on the coefficient of friction Pressure of the leak-proof ring on the impeller Diameter at the contact point between the rotating wheel and the leak-proof ring List the flow rate based on the impeller speed ω. Heat generation of the lower sealing ring equation; S3.3. Based on the basic forced convection heat transfer formula, list the flow rate. Heat dissipation of the lower sealing ring equation; S3.4, Heat generation during the construction of the leak-proof ring With heat dissipation The heat balance equation makes ; S3.5. Based on the heat balance equation, iteratively solve for the optimal flow rate of the leak-proof ring water supply pipeline. ; S3.6, Based on optimal flow The optimal cross-sectional area of ​​the throttle valve orifice is obtained. ; S3.7, Based on the coefficient of friction Calculation equations, heat balance equations, and optimal flow rates Establish the optimal cross-sectional area The mapping relationship with rotational speed ω.

[0012] Furthermore, in step S3, the different lubrication zones include a boundary lubrication zone, a mixed lubrication zone, and a fluid lubrication zone, when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is the boundary lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the fluid lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the mixed lubrication range; among which, This is the critical flow rate for transitioning from the boundary lubrication zone to the mixed lubrication zone; This is the critical flow rate required to transition from the mixed lubrication zone to the fluid lubrication zone.

[0013] Furthermore, in step S3.1, the coefficient of friction The calculation equation is: , In the formula, The coefficient of dry friction is The slope of the decreasing coefficient of friction for boundary lubrication. For mixed lubrication friction coefficient, The slope of the decreasing friction coefficient for mixed lubrication. is the coefficient of friction for fluid lubrication.

[0014] Furthermore, in step S3.5, the optimal flow rate is iteratively solved. The method includes the following steps: a. Select initial flow rate and make traffic =Initial flow ; b. Determine the flow rate The lubrication range in which the friction coefficient is determined And based on the determined coefficient of friction Substitute the heat output Equations for calculating flow rates The heat generated below ; c. Based on heat dissipation Equations for calculating flow rates Heat dissipation of the lower sealing ring ; d. Comparison of calorific value and heat dissipation If heat generation > Heat dissipation Increase the flow rate And return to step b; if heat generation Heat dissipation Then reduce the flow rate. And return to step b; e. Repeat steps a to d until the heat balance equation is satisfied. And the temperature of the leak-proof ring wall surface ≤ Maximum allowable temperature of the leak-proof ring sealing material The flow rate at this time That is, the optimal flow rate .

[0015] Furthermore, in step S3.2, the heat generation... The equation is: , In the formula, The pressure of the stop-leak ring on the impeller.

[0016] Furthermore, in step S3.3, the basic forced convection heat transfer calculation formula is: , In the formula, h is the convective heat transfer coefficient, with units of W / (m²). K), convective heat transfer coefficient h and flow rate Related; The effective heat exchange area between the cooling water and the leak-proof ring, in units of ; This refers to the heat exchange temperature difference, expressed in Kelvin (K). That is, the temperature of the leak-proof ring wall surface With average cooling water temperature The difference; the heat exchange temperature difference Substituting into the basic forced convection heat transfer formula, we obtain the heat dissipation. The equation is: , In the formula, To prevent leakage, the flow rate of the water supply pipeline The convective heat transfer coefficient below.

[0017] Furthermore, assuming the cooling water temperature in the leak-stop ring supply pipeline is 40℃, and using the Dittus-Boelter equation, the following calculations were performed: , In the formula, The cross-sectional area of ​​the water flow at the contact point between the leak-stop ring and the impeller.

[0018] Furthermore, in step e, based on the heat balance equation, the simultaneous heat balance equations are obtained as follows: , In the formula, .

[0019] Furthermore, in step S3.6, the optimal cross-sectional area of ​​the throttle valve orifice... The method for obtaining the value is as follows: using the inlet and outlet sections of the throttle valve as the calculation sections, the following Bernoulli equation is derived: , Based on the assumed conditions, the optimal flow rate of the water supply pipeline for the leak-proof ring was derived. Optimal cross-sectional area of ​​throttle valve orifice The relation is: , The combined assumption is that the flow velocities at the inlet and outlet sections of the throttle valve are approximately equal, i.e. The inlet and outlet cross-sectional heights of the throttle valve are equal. ; In the formula, The flow coefficient of the throttle valve. The constant pressure difference between the inlet and outlet of the throttle valve is... , The pressure at the inlet section of the throttle valve. The pressure at the outlet section of the throttle valve. Where is the fluid density, and g is the acceleration due to gravity. The flow velocity at the inlet section of the throttle valve is... The velocity at the outlet section of the throttle valve is... The height of the throttle valve inlet section. This refers to the height of the outlet section of the throttle valve.

[0020] Furthermore, in step 3.7, the optimal cross-sectional area... The mapping relationship with rotational speed ω is as follows: , In the formula, , .

[0021] Furthermore, in step S4, the water level height is related to the air leakage time in the impeller chamber and the optimal flow rate of the water supply pipeline for the leak-proof ring. The relationship is as follows: , In the formula, H is the water level in the runner chamber, and t is the air leakage time in the runner chamber. This refers to the leakage flow rate of the cooling water in the turbine chamber. The equivalent cross-sectional area of ​​the turbine runner and the leakage flow rate of the cooling water in the turbine runner. Equivalent cross-sectional area of ​​the turbine chamber All are set to constant values.

[0022] Furthermore, in step S5, the actuating elements in the leak-proof ring water supply system model include an upper leak-proof ring check valve, a lower leak-proof ring check valve, a throttle valve, a leak-proof ring electric ball valve, and a leak-proof ring check valve; the detection elements include an upper leak-proof ring flow meter, a lower leak-proof ring flow meter, and a leak-proof ring pressure gauge. The actuating elements in the pneumatic pressurized water gas-liquid mixing system model include a pneumatic throttle valve, a pneumatic hydraulic valve, a pneumatic solenoid directional valve, a pneumatic check valve, a replenishing hydraulic valve, a replenishing solenoid directional valve, a replenishing check valve, a replenishing throttle valve, an exhaust throttle valve, an exhaust electric ball valve, an exhaust hydraulic valve, and an exhaust solenoid directional valve. The actuating elements in the turbine model include a runner, and the detection elements include a level gauge connected to the tailrace pipe.

[0023] Furthermore, the simulation method also includes: Step S6: Build a visual operation interface. The visual operation interface communicates with the leak-stopping ring water supply system model, the air-pressurized water gas-liquid mixing system model, the turbine model and the control system to realize the phase adjustment condition conversion, real-time monitoring, interactive operation and status warning of the pressurized water phase adjustment system simulation.

[0024] The advantages of using this invention are: 1. The simulation method of the present invention, through analysis and parameter extraction, makes the constructed framework model of the hydropower unit pressurized water phase regulation simulation system simple in structure, and can reproduce the layout of each action element and detection element in the actual hydropower unit pressurized water phase regulation system one-to-one, laying the foundation for the framework construction of the hydropower unit pressurized water phase regulation simulation system.

[0025] 2. The simulation method of this invention, through the construction of a leak-stop ring water supply system model, an air-pressurized water gas-liquid mixing system model, and a turbine model, forms three mutually cooperating subsystems in the hydropower unit pressurized water phase regulation simulation system. These three subsystems together constitute a motion-thermal-gas-liquid mixed multiphysics model to simulate the real-world scenario of hydropower unit pressurized water phase regulation, avoiding the complexity of directly modeling the large motor structure. This retains key dynamic characteristics while improving simulation efficiency. Specifically, the leak-stop ring water supply system model represents the sealing, lubrication, and cooling processes between the leak-stop ring and the runner; the air-pressurized water gas-liquid mixing system model represents the air-pressurized water and exhaust / return water conditions of the runner chamber; and the turbine model represents the angular velocity control of the runner rotation, the frictional heat generation between the runner and the leak-stop ring, and the water level changes in the runner chamber under air-pressurized water conditions.

[0026] Furthermore, the motion-thermal-gas-liquid hybrid multiphysics model composed of three subsystems can simulate the real operation scenario of pressurized water phase regulation of hydropower units. Therefore, it can be directly applied to scheme verification and reliability evaluation during the system design stage, thus providing effective support for the pressurized water phase regulation retrofit of conventional hydropower units and the design and optimization of pressurized water phase regulation systems for pumped storage units.

[0027] 3. The simulation method of this invention, by setting different rotational speeds of the turbine runner in the turbine model, obtains the optimal cross-sectional area of ​​the throttle valve orifice required for different rotational speeds based on the optimal flow rate of the leak-proof ring water supply pipeline and Bernoulli's equation; according to the flow rate of the leak-proof ring water supply pipeline, the contact friction state between the leak-proof ring and the runner is divided into different lubrication zones, and a mapping relationship between the optimal cross-sectional area and the rotational speed is established based on the different lubrication zones; then, based on the mapping relationship, a leak-proof ring water supply system model adapted to different rotational speeds is constructed within the second framework; the establishment of the leak-proof ring water supply system model characterizes the dynamic closed-loop coupling model of the leak-proof ring "flow-friction-heat", enabling the leak-proof ring water supply system to automatically adjust the throttle valve opening according to the runner rotational speed, realizing real-time simulation and dynamic control of the leak-proof ring temperature. The constructed mapping relationship establishes the correlation between the cross-sectional area of ​​the throttle valve orifice and the speed of the impeller, enabling it to adapt to different speeds. This effectively simulates the dynamic control mechanism of the actual hydropower unit's pressurized water phase regulation system in maintaining the thermal balance of the leak-proof ring and stabilizing its temperature within a safe range, providing a practical simulation for the safe and stable operation of the hydropower unit's pressurized water phase regulation system.

[0028] 4. The simulation method of this invention establishes a relationship between the water level in the runner chamber of the turbine model and the air leakage time in the runner chamber, as well as the optimal flow rate of the water supply pipeline of the leak-proof ring. Combined with the hydraulic and pneumatic systems in the pressurized water phasing system, an air-filled pressurized water gas-liquid mixing system model is constructed within the third framework. This simulates the complete process of compressed air being injected into the runner chamber through the air inlet pipeline, forming and maintaining an air cushion, thus realizing the actual simulation of the air-filled pressurized water gas-liquid mixing system model. Furthermore, it simulates the operation of the pressurized water phasing simulation system of the hydropower unit under different speeds and phasing conditions, comprehensively demonstrating the performance of the hydraulic system under different states, including flow fluctuations, pipeline pressure, water level changes, and heat dissipation. This provides more comprehensive data support for the design optimization of the pressurized water phasing system of the hydropower unit and can also detect potential problems that may occur in the actual pressurized water phasing system of the hydropower unit under different operating conditions in advance, greatly reducing the difficulty of fault prediction.

[0029] 5. The simulation method of this invention, by constructing a control system, accurately simulates the shutdown and phase-shifting conditions of hydropower units, as well as the transition processes between shutdown and phase-shifting, power generation and phase-shifting, phase-shifting and shutdown, and phase-shifting and power generation. This control system performs real-time monitoring and intelligent control of the various motion and detection elements in the motion-thermal-gas-liquid mixed multiphysics model, thereby precisely driving the automatic transition and stable maintenance between different actions such as aeration and water pressurization, and exhaust and water return.

[0030] 6. The simulation method of the present invention, by building a visual operation interface and communicating with the leak-stopping ring water supply system model, the air-pressurized water gas-liquid mixing system model, the turbine model and the control system, realizes the phase adjustment condition conversion, real-time monitoring, interactive operation and status early warning of the pressurized water phase adjustment system simulation, thereby improving the engineering applicability and human-computer interaction of the hydropower unit pressurized water phase adjustment simulation system.

[0031] Furthermore, by cooperating with the leak-stopping ring water supply system model, the air-pressurized water gas-liquid mixing system model, the turbine model, and the control system, the visual operation interface has three major functions: fault simulation, rapid system performance verification, and personnel operation training. This provides a reliable data foundation for subsequent fault diagnosis and analysis, enables rapid and accurate location of fault points, thereby significantly improving debugging efficiency and accuracy, and greatly reducing debugging costs.

[0032] Meanwhile, by cooperating with the leak-stopping ring water supply system model, the air-pressurized water gas-liquid mixing system model, the turbine model, and the control system, operators can intuitively grasp the complex internal operating mechanism of the pressurized water phase adjustment system through a visual operating interface. This avoids the risk of unit damage or safety accidents that may be caused by directly operating real equipment, and provides operators with a safe, efficient, and intuitive learning path and training platform.

[0033] In summary, the simulation method for the pressurized water phase regulation system of hydropower units provided by this invention effectively solves the technical problems of low design reliability, poor commissioning efficiency, training difficulties, and difficulty in fault prediction caused by the lack of a complete simulation model in the prior art. It realizes full-condition simulation of the pressurized water phase regulation process of hydropower units, and significantly improves the reliability, commissioning efficiency, and operational safety of the pressurized water phase regulation system design of hydropower units. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the simulation system of the pressurized water phase adjustment system of the hydropower unit in this invention.

[0035] Figure 2 This is a schematic diagram of the structure of the motion-thermal-gas-liquid hybrid multiphysics model in the simulation system of this invention.

[0036] The diagram is labeled as follows: 1. Visualized operating interface; 2. Motion-thermal-gas-liquid mixing multiphysics model; 3. Leak-stop ring water supply system model; 4. Air-pressurized water gas-liquid mixing system model; 5. Turbine model; 6. Control system; 7. Upper leak-stop ring water supply pipeline; 8. Lower leak-stop ring water supply pipeline; 9. Leak-stop ring water supply pipeline; 10. Air inlet pipeline; 11. Oil inlet pipeline; 12. Exhaust pipeline; 13. Runner chamber; 14. Air-pressurized throttle valve; 15. Oil discharge pipeline; 16. Exhaust throttle valve; 17. Exhaust electric ball valve; 18. Exhaust hydraulic valve. 9. Air replenishment hydraulic valve; 20. Air charging hydraulic valve; 21. Exhaust solenoid directional valve; 22. Air replenishment solenoid directional valve; 23. Air charging solenoid directional valve; 24. Upper check ring check valve; 25. Lower check ring check valve; 26. Upper check ring flow meter; 27. Lower check ring flow meter; 28. Throttle valve; 29. ​​Tailwater pipe; 30. Check ring electric ball valve; 31. Check ring pressure gauge; 32. Check ring check valve; 33. Air replenishment check valve; 34. Air charging check valve; 35. Air replenishment throttle valve; 36. Level gauge; 37. Check ring; 38. Rotary wheel. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. For ease of description, the description of the relative positional relationships of each component is based on the layout of the accompanying drawings, such as the positional relationships of front, back, top, bottom, left, right, etc., which are determined according to the layout direction of the accompanying drawings.

[0038] Example 1 like Figure 1 and Figure 2 As shown in the figure, as a basic embodiment of the present invention, the present invention provides a simulation method for a hydropower unit pressurized water phase regulation system, the method comprising the following steps: S1. Analyze and extract parameters of the pressurized water phase regulation system to be configured for the hydropower unit, and build the first framework, the second framework and the third framework.

[0039] In this step, the analysis of the pressurized water phase adjustment system to be configured for the hydropower unit is based on its design drawings, pipeline diagrams and assembly technical data to clarify all core components of the air-pressurized water hydraulic system and the upper and lower leak-proof ring water supply system, such as the models, spatial layout and functional connections of various hydraulic valves, solenoid directional valves, throttle valves, pipelines and leak-proof ring pressure gauges, and leak-proof ring flow meters.

[0040] Parameter extraction involves extracting and quantifying the key parameters required for modeling from the analyzed technical data to form an initial parameter set. The extracted parameters mainly involve: pipeline parameters, such as the nominal diameter and length of major pipelines like the air intake pipeline 10 and the water supply pipeline 9 with the leak-proof ring; and component parameters, such as the valve core stroke, diameter, and specifications of hydraulic valves, as well as the response time and rated flow of solenoid directional valves, forming a parameter list.

[0041] Therefore, based on the results of the analysis, a foundation was laid for reproducing the component layout and physical connection relationship of the actual hydropower unit's pressurized water phase regulation system in the simulation environment.

[0042] S2. Based on the water level in the runner chamber, a turbine model 5 under different phase adjustment conditions is constructed within the first frame. The phase adjustment conditions include air-pressurized water condition, stable phase adjustment condition, and exhaust water return condition.

[0043] The constructed turbine model 5 characterizes the rotational motion characteristics of the runner 38 under three phase-adjustment conditions: air-pressurized water, stable phase adjustment, and exhaust water return. These characteristics include parameters such as the drag torque, angular velocity, and moment of inertia of the runner when rotating in air. Its operating state directly affects the flow field distribution within the runner chamber 13 and the heat generation of the leak-proof ring 37.

[0044] S3. Set different rotational speeds ω of the runner in turbine model 5, based on the optimal flow rate of the water supply pipeline 9 under the leak-proof ring. Using Bernoulli's equation, the optimal cross-sectional area of ​​the throttle valve orifice 28 required for different rotational speeds ω is obtained. According to the flow rate of the water supply pipe 9 of the leak-proof ring. The size is used to divide the contact friction state between the leak-proof ring 37 and the rotating wheel 38 into different lubrication zones, and an optimal cross-sectional area is established according to the different lubrication zones. The mapping relationship between the speed ω and the rotation speed ω is then used to construct a leak-proof ring water supply system model 3 that adapts to different rotation speed ω within the second framework based on the mapping relationship.

[0045] In step S3, the essence is to establish a leak-proof ring "flow-friction". The "thermal" dynamic closed-loop coupling model enables the leak-stop ring water supply system model 3 to automatically adjust the cross-sectional area of ​​the throttle valve 28 according to the impeller speed ω, thereby realizing the actual simulation and dynamic control of the temperature at the leak-stop ring. The optimal cross-sectional area is established. The mapping relationship with rotational speed ω effectively simulates the dynamic control mechanism that maintains the thermal balance of the leak-proof ring 37 and keeps its temperature within a safe range.

[0046] Furthermore, the different speeds ω of the turbine model 5 are set manually. The speed settings are primarily based on the following factors: Under air-pressurized water conditions, to meet the requirements of phase-shifting operation, the runner 38 needs to rotate in the air and maintain a sufficiently high speed ω to generate enough reactive power to support the grid voltage; simultaneously, the friction between the runner 38 and the leak-proof ring 37 intensifies with increasing speed, and excessively high speed ω can lead to increased heat generation, potentially causing the leak-proof ring to overheat. Therefore, setting the runner speed ω under different phase-shifting conditions provides a key input for constructing the leak-proof ring water supply system model, enabling effective lubrication and cooling of the leak-proof ring 37. It should be noted that the runner speed ω changes dynamically under the same operating condition. For example, in stable phase-shifting operation, the runner speed ω needs to gradually increase from zero to the rated value; while when switching to the exhaust and return water condition, the runner speed ω needs to be gradually reduced to zero before performing the exhaust operation.

[0047] S4. Based on the water level in the runner chamber of turbine model 5, establish the relationship between water level and runner chamber air leakage time t, and the optimal flow rate of the leak-proof ring water supply pipeline 9. Based on the relationship, and combining the hydraulic and pneumatic systems in the pressurized water phase adjustment system, a model 4 of the pressurized water gas-liquid mixing system is constructed within the third framework.

[0048] Water level height and air leakage time in the impeller chamber, optimal flow rate of the leak-proof ring water supply line 9 The relationship is as follows: , In the formula, H is the water level in the runner chamber, and t is the air leakage time in the runner chamber. This refers to the leakage flow rate of the cooling water in the turbine chamber. The equivalent cross-sectional area of ​​the turbine runner and the leakage flow rate of the cooling water in the turbine runner. Equivalent cross-sectional area of ​​the turbine chamber All values ​​are set as constants; the specific values ​​for these constants depend on the actual conditions of the power plant: the typical value for leakage flow is 1 m³ / s. 3 / h; The equivalent cross-sectional area is usually characterized by the area of ​​the equivalent circle, and its equivalent diameter typically ranges from 3 to 10 m.

[0049] In addition, such as Figure 2As shown, the water level height H in the runner chamber is monitored by a liquid level gauge 36 connected to the draft tube 29. At the same time, the lower limit Hmin and upper limit Hmax of the water level height are preset according to actual needs. The control logic of the pneumatic pressurized water-gas-liquid mixing system model 4 is as follows: when H < Hmin, the inflation stops; when H > Hmax, air is supplemented, thereby simulating the physical process of air inflation and phase modulation of an actual hydro-generator unit.

[0050] Furthermore, the pneumatic pressurized water-gas-liquid mixing system model 4 transports hydraulic oil through a hydraulic system via an oil inlet pipeline 11 to control the opening and closing of an electromagnetic directional valve, and then adjusts the actions of relevant hydraulic valves to achieve precise opening and closing of the valves. At the same time, the pneumatic system cooperates with the air inlet pipeline 10 to perform inflation, air supplementation, or exhaust operations, and cooperates with the hydraulic system to complete the dynamic regulation of the gas-liquid interface. By simulating the operation of the hydro-generator unit's water suppression and phase modulation system under different rotational speeds and different phase modulation conditions, the performance of the hydraulic system is comprehensively presented, including key parameters such as flow rate fluctuations, pipeline pressure changes, water level dynamic responses, and heat dissipation and cooling effects, providing more comprehensive data support for the design optimization of the water suppression and phase modulation system, and detecting potential problems that may occur in the water suppression and phase modulation system under different operating states in advance, such as abnormal pressure or gas-liquid imbalance, etc., thereby providing a basis for subsequent improvements.

[0051] So far, in steps S1 to S4, through the construction of the seal ring water supply system model 3, the pneumatic pressurized water-gas-liquid mixing system model 4, and the water turbine model 5, three subsystems that cooperate with each other in the water suppression and phase modulation simulation system of the hydro-generator unit as shown in Figure 1 are formed, and they together constitute the multi-physical field model 2 of motion-thermodynamics-gas-liquid mixing. Among them, the seal ring water supply system model 3 is used to simulate the sealing, lubrication, and cooling processes of the seal ring 37 and the runner 38; the pneumatic pressurized water-gas-liquid mixing system model 4 is used to simulate the pneumatic pressurization of water and exhaust and return water conditions in the runner chamber 13; the water turbine model 5 is used to simulate the angular velocity control of the rotation of the runner 38, the heat generation due to friction between the runner 38 and the seal ring 37, and the change in the water level height in the runner chamber 13 under the pneumatic pressurization of water condition. Specifically, simulating the change in the water level height in the runner chamber 13 under the pneumatic pressurization of water condition is a comprehensive simulation of the gas-liquid equilibrium state in the runner chamber 13, including both the decrease in the water level caused by the increase in the gas volume under the pneumatic pressurization of water condition and the decrease in the gas volume and the rise in the water level caused by potential factors such as air leakage in the runner chamber or water leakage in the seal ring.

[0052] It should be noted that in steps S1 to S4, theoretical modeling is also required for the actuators in the pneumatic pressurized water gas-liquid mixing system model 4, as well as the detection and actuators in the leak-stop ring water supply system model 3 and the turbine model 5. This lays the theoretical foundation for achieving multi-physics dynamic simulation. When theoretically modeling the pneumatic pressurized water system, leakage must be considered, simulating the attenuation of gas flow after the runner chamber is filled, especially during the filling and replenishment stages for greater realism. The exhaust hydraulic valve 18 adopts a linearized dynamic flow model, balancing accuracy and computational efficiency. When theoretically modeling the inlet and outlet oil lines 11 and 15, local pressure loss must be considered to accurately assess the total pressure drop in complex pipeline layouts, particularly suitable for multi-bend, long-distance oil circuit systems. When theoretically modeling the turbine, rotational speed and friction coefficient are also considered, significantly improving the simulation accuracy under conditions such as rapid start-up and shutdown, and sudden load changes, avoiding numerical instability caused by rigid assumptions. Since the modeling process and methods for detection and actuators are conventional techniques, they will not be elaborated here.

[0053] S5. Build control system 6, connect control system 6 to the detection element and action element in the leak-stop ring water supply system model 3, connect to the action element in the air-pressurized water gas-liquid mixing system model 4, and connect to the detection element and action element in the water turbine model 5, realize the signal acquisition of the detection element and the action control of the action element, and complete the simulation of the pressurized water phase adjustment system.

[0054] Furthermore, such as Figure 2 As shown, the actuating elements in the leak-stop ring water supply system model 3 include an upper leak-stop ring check valve 24, a lower leak-stop ring check valve 25, a throttle valve 28, a leak-stop ring electric ball valve 30, and a leak-stop ring check valve 32. The detection elements in the leak-stop ring water supply system model 3 include an upper leak-stop ring flow meter 26, a lower leak-stop ring flow meter 27, and a leak-stop ring pressure gauge 31.

[0055] The actuating components in the pneumatic pressurized water gas-liquid mixing system model 4 include a pneumatic throttle valve 14, a pneumatic hydraulic valve 20, a pneumatic solenoid directional valve 23, a pneumatic check valve 34, a replenishing hydraulic valve 19, a replenishing solenoid directional valve 22, a replenishing check valve 33, a replenishing throttle valve 35, an exhaust throttle valve 16, an exhaust electric ball valve 17, an exhaust hydraulic valve 18, and an exhaust solenoid directional valve 21. The moving elements in the turbine model 5 include the runner 38, and the detection elements in the turbine model 5 include the level gauge 36 connected to the tailrace pipe.

[0056] In step S5, to enable the hydropower unit to switch between various operating conditions, such as shutdown, phase adjustment, and transitions between shutdown and phase adjustment, power generation and phase adjustment, phase adjustment and shutdown, and phase adjustment and power generation, a unified control system 6 is built on the existing kinematic-thermal-gas-liquid hybrid multiphysics field model, which includes the leak-stopping ring water supply system model 3, the air-pressurized water gas-liquid mixing system model 4, and the turbine model 5. This control system 6, through preset program logic, achieves real-time monitoring and intelligent control of the actuators and detection elements, thereby precisely driving the automatic switching and stable maintenance between different operating conditions, such as air-pressurized water phase adjustment, stable phase adjustment, and exhaust water return. In other words, the leak-stopping ring water supply system model 3, the air-pressurized water gas-liquid mixing system model 4, and the turbine model 5 do not operate independently; they are all integrated under the architecture of the control system 6, which coordinates data interaction and collaborative operation between the models.

[0057] Step S6: Build a visual operation interface 1. The visual operation interface 1 communicates with the leak-stopping ring water supply system model 3, the air-pressurized water gas-liquid mixing system model 4, the water turbine model 5, and the control system 6 to realize the phase adjustment condition conversion, real-time monitoring, interactive operation, and status early warning of the pressurized water phase adjustment system simulation.

[0058] Specifically, the visual operation interface 1 integrates the following functions: First, it is used for real-time monitoring: through multi-dimensional forms such as graphs, curves and data forms, it dynamically displays the real-time changes of key parameters such as air pressure, water level, flow rate and temperature; Second, it is used for interactive operation: it supports direct operation of simulation system components through interface commands, such as controlling the opening and closing of valves such as hydraulic valves, electromagnetic reversing valves, and electric ball valves, and observing in real time the state changes and simulation responses of the hydropower unit pressure water phase adjustment simulation system caused by the operation. The system state includes real-time parameters such as air pressure, water level, flow rate and temperature; Third, it is used for status early warning: based on the calculation results of the motion-thermal-gas-liquid mixed multiphysics model 2, it provides early warning prompts for potential faults such as abnormal air pressure and excessive water level, assisting operators to intervene in a timely manner.

[0059] Example 2 Based on Example 1, the optimal cross-sectional area in step S3 of the present invention is... The method for establishing the mapping relationship with rotational speed ω has been optimized.

[0060] Optimal cross-sectional area The method for establishing the mapping relationship with rotational speed ω specifically includes the following steps: S3.1, Based on flow rate The coefficient of friction is listed for different lubrication ranges. Calculate the equation; S3.2, Based on the coefficient of friction Pressure of the leak-proof ring on the impeller Diameter at the contact point between the rotating wheel and the leak-proof ring List the flow rate based on the impeller speed ω. Heat generation of the lower sealing ring equation; S3.3. Based on the basic forced convection heat transfer formula, list the flow rate. Heat dissipation of the lower sealing ring equation; S3.4, Heat generation during the construction of the leak-proof ring With heat dissipation The heat balance equation makes ; S3.5. Based on the heat balance equation, iteratively solve for the optimal flow rate of the leak-proof ring water supply pipe 9. ; S3.6, Based on optimal flow The optimal cross-sectional area of ​​the throttle valve orifice is obtained. ; S3.7, Based on the coefficient of friction Calculation equations, heat balance equations, and optimal flow rates Establish the optimal cross-sectional area The mapping relationship with rotational speed ω.

[0061] Furthermore, in step S3.1, the different lubrication zones include the boundary lubrication zone, the mixed lubrication zone, and the fluid lubrication zone, when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is the boundary lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the fluid lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the mixed lubrication range; among which, This is the critical flow rate for transitioning from the boundary lubrication zone to the mixed lubrication zone; This is the critical flow rate required to transition from the mixed lubrication zone to the fluid lubrication zone.

[0062] In other words, the lubrication state and friction coefficient of the leak-proof ring 37 and the rotating wheel 38 There is a correlation: the thickness of the lubricating film formed by the cooling water on the contact surface area between the leak-proof ring 37 and the impeller 38 directly determines the friction state and coefficient of friction in that contact area. The numerical value, and the flow rate of the leak-proof ring water supply pipe 9. This is a key factor affecting the thickness of the lubricating film. However, the flow rate may vary depending on the application scenario, and there is no single, fixed value. Generally, Roughly on the order of 100 L / min It is roughly on the order of 10,000 L / min.

[0063] When in the boundary lubrication zone: Flow rate of the leak-proof ring water supply line 9 The lubricating film is very small, and the leak-proof ring 37 and the rotating wheel 38 are in direct metal-to-metal contact. The friction is large, the sealing rubber is in direct contact with the steel, the heat generation is severe, and the parts are prone to wear.

[0064] When in the mixed lubrication zone: Flow rate of the leak-proof ring water supply line 9 The friction is moderate, with the lubricating film covering about half of the surface. The leak-proof ring 37 and the rotating wheel 38 are in partial metal-to-metal contact. There is a water film layer between some of the rubber and steel. Dry friction and fluid lubrication coexist in different local areas. The friction is moderate, and the heat generation is moderate.

[0065] When in the fluid lubrication zone: Flow rate of the leak-proof ring water supply line 9 Sufficient lubrication is provided, with the lubricating film covering most of the surface. There is no metal-to-metal contact between the leak-proof ring 37 and the rotating wheel 38. The metal and rubber do not come into direct contact and are completely separated by water. Friction is mainly caused by internal shearing within the liquid, resulting in minimal friction, slight heat generation, and minimal wear on components.

[0066] Therefore, the critical flow threshold is set based on tribological theory and accepted engineering experience data. and critical flow threshold And based on traffic The different lubrication zones will affect the coefficient of friction. The equation is divided into three parts; therefore, in step S3.1, the coefficient of friction... The calculation equation is: , In the formula, The coefficient of dry friction is The slope of the decrease in the boundary lubrication friction coefficient is a fixed value; For mixed lubrication friction coefficient, The slope of the decreasing friction coefficient for mixed lubrication. It is also a fixed value; is the coefficient of friction for fluid lubrication.

[0067] for The coefficient of friction is the dry friction coefficient, i.e., the friction coefficient under dry friction conditions without lubrication. The commonly used reference value for the friction coefficient of steel-ordinary rubber in engineering is 0.8 to 1.0. Here, for the sealed structure, it is taken as 0.8 to 0.9. For accurate calculation, actual measurement is required. for In mixed lubrication, i.e., water lubrication, where a partial water film and a portion of the rubber-metal interface are in direct contact, the coefficient of friction between steel and ordinary rubber is typically between 0.15 and 0.40, much lower than the coefficient of friction in dry lubrication. (0.8~1.0), actual measurement is required for precise calculation; for The coefficient of friction for fluid lubrication is: under fluid lubrication conditions where the rubber and metal are completely separated by a water film and have no direct contact, friction is mainly due to internal shearing within the liquid and is supported by the water film. The rubber experiences almost no wear, and the coefficient of friction is as low as 0.001~0.05, which is 1~2 orders of magnitude lower than that for dry friction.

[0068] Example 3 Based on Example 2, the optimal flow rate of the leak-stopping ring water supply pipeline 9 in S3.5 is iteratively solved. The method has been optimized, specifically including the following steps: a. Select initial flow rate and make traffic =Initial flow ; b. Determine the flow rate The lubrication range in which the friction coefficient is determined And based on the determined coefficient of friction Substitute the heat output Equations for calculating flow rates The heat generated below ; c. Based on heat dissipation Equations for calculating flow rates Heat dissipation of the lower sealing ring ; d. Comparison of calorific value and heat dissipation If heat generation > Heat dissipation Increase the flow rate And return to step b; if heat generation Heat dissipation Then reduce the flow rate. And return to step b; e. Repeat steps a to d until the heat balance equation is satisfied. And the temperature of the leak-proof ring wall surface ≤ Maximum allowable temperature of the leak-proof ring sealing material The flow rate at this time That is, the optimal flow rate .

[0069] In this iterative solution method, the flow rate is used for repeated calculations between steps b and d. It is an iterative variable that is constantly updated. Its initial value is Q0, and it is subsequently increased or decreased based on the heat balance judgment result in step d. Finally, when the convergence condition of step e is met, the current flow rate... This is the optimal flow rate. .

[0070] Example 4 Based on Example 3, in this example, the heat generated by the leak-proof ring is... Heat dissipation of the leak-proof ring The calculation method has been optimized, as follows: In step S3.2, the heat generation The equation is: , In the formula, The pressure of the leak-stop ring 37 on the rotor 38.

[0071] In step S3.3, the basic forced convection heat transfer calculation formula is: , In the formula, h is the convective heat transfer coefficient, with units of W / (m²). K), convective heat transfer coefficient h and flow rate Related; The effective heat exchange area between the cooling water and the leak-proof ring, in units of ; This refers to the heat exchange temperature difference, expressed in Kelvin (K). That is, the temperature of the leak-proof ring wall surface With average cooling water temperature The difference; the heat exchange temperature difference Substituting into the basic forced convection heat transfer formula, we obtain the heat dissipation. The equation is: , In the formula, 9 flow rates for leak-proof water supply pipeline The convective heat transfer coefficient at the following values, The range is 1000-15000 W / (m²) K).

[0072] Furthermore, under the premise that the temperature of the cooling water in the leak-stop ring water supply pipe 9 is 40℃, and using the Dittus-Boelter equation, the following calculations were performed: , In the formula, The cross-sectional area of ​​the water flow at the contact point between the leak-stop ring and the impeller.

[0073] Specifically, according to the formula for calculating the convective heat transfer coefficient in thermodynamics: Taking a cooling water temperature of 40℃ supplied by the leak-proof ring water supply pipe 9 as an example, the Dittus-Boelter equation is used to estimate the Nusselt number for this environment. The formula for calculating the Nusselt number is as follows: , In the formula, Re is the Reynolds number and Pr is the Prandtl number.

[0074] The formula for calculating the Reynolds number Re is as follows: , In the formula, ν is the kinematic viscosity; λ is the thermal conductivity of the fluid.

[0075] In summary, traffic The convective heat transfer coefficient below The calculation formula is: , By consulting the Prandtl number (Pr) and kinematic viscosity (ν) tables for water at different temperatures, as well as the thermal conductivity (λ) table, we found that for cooling water at 40℃, Pr = 4.31 and ν = 0.658 × 10⁻⁶. 6 m 2 / s, λ = 0.633 W / (m K).

[0076] Substituting the data obtained from the above table into the convective heat transfer coefficient From the formula: , Traffic Substitution Heat dissipation of the leak-proof ring The calculation formula yields the heat dissipation of the leak-proof ring when the cooling water temperature is 40℃: .

[0077] It should be noted that in pumped storage hydroelectric generator units, because pumped storage hydroelectric generator units have an additional spiral casing pressure-regulating pipeline compared to conventional hydroelectric generator units, the water supply flow rate of the leak-proof loop pipeline is... All the water is used for cooling the sealing ring, but not all of it is used for lubrication. Therefore, the water supply flow rate in the sealing ring pipeline... For the flow rate involved in the lubrication of the sealing ring Flow rate of the volute pressure line The sum is: .

[0078] Furthermore, in step e of Example 3, based on the heat balance equation, the simultaneous heat balance equations are obtained as follows: , In the formula, .

[0079] Furthermore, in step g, the calculated heat generation of the leak-proof ring is... With heat dissipation Construct a heat balance equation to make Substituting the values, we get: , In the formula, , To set the maximum permissible operating temperature of the sealing ring. Therefore, if the sealing ring wall temperature... Exceeding the maximum allowable operating temperature of the sealing ring material Increased flow is required To improve the convective heat transfer coefficient Increase heat dissipation; conversely, decrease flow rate. In order to reduce .

[0080] This achieves the dynamic control logic shown in Table 1: Table 1. Dynamic Adjustment Control Logic Table for Leakage-Suppressing Ring Wall Temperature

[0081] Example 5 Based on Example 4, this example optimizes the cross-sectional area of ​​the throttle valve orifice in step S3.6. The method for obtaining [the data] has been optimized, as follows: Using the inlet and outlet sections of the throttle valve as the calculation sections, the following Bernoulli equation is derived: , Based on the assumed conditions, the optimal flow rate of the leak-proof ring water supply pipeline 9 was derived. Optimal cross-sectional area of ​​throttle valve orifice The relation is: , The assumption is that the flow velocities at the inlet and outlet sections of the throttle valve are approximately equal, i.e. The inlet and outlet cross-sectional heights of the throttle valve are equal. ; In the formula, The flow coefficient of the throttle valve. The constant pressure difference between the inlet and outlet of the throttle valve is... , The pressure at the inlet section of the throttle valve. The pressure at the outlet section of the throttle valve. Where is the fluid density, and g is the acceleration due to gravity. The flow velocity at the inlet section of the throttle valve is... The velocity at the outlet section of the throttle valve is... The height of the throttle valve inlet section. This refers to the height of the outlet section of the throttle valve.

[0082] Example 6 Based on Example 5, this example further refines the optimal cross-sectional area established in step S3.7. The mapping relationship with rotational speed ω is as follows: , Specifically, the cross-sectional area of ​​the throttle valve in different lubrication zones The process of refining the model related to rotational speed ω is as follows: Zone 1: The contact friction state between the leak-proof ring 37 and the rotating wheel 38 is the boundary lubrication zone, i.e. The time sorting process is as follows: The equation for the friction coefficient in this interval is known to be: Solve the simultaneous heat balance equations The heat balance equation at a cooling water temperature of 40℃ is obtained by rearranging: Simplified to: .

[0083] in, , It is a constant value; according to , deformed , The flow coefficient is a constant. After sorting, we get: .

[0084] It should be noted that the optimal flow rate is obtained through iterative solutions. By constructing the heat balance equation, we can determine the flow rate during the preparation process. That is, the optimal flow rate of the leak-proof loop water supply pipe 9 Correspondingly, the optimal flow rate for the leak-proof ring water supply pipeline is 9. The corresponding area is the optimal cross-sectional area of ​​the throttle valve orifice. .

[0085] Section Two: The contact friction state between the leak-proof ring 37 and the rotating wheel 38 is a mixed lubrication zone, i.e. The time sorting process is as follows: The equation for the friction coefficient in this interval is known to be: Solve the simultaneous heat balance equations By combining the logic of the same interval and replacing only the parameters related to the friction coefficient, the final heat balance equation at a cooling water temperature of 40℃ is: .

[0086] Section 3: The contact friction state between the leak-proof ring 37 and the rotating wheel 38 is in the fluid lubrication zone, i.e. The time sorting process is as follows: The equation for the friction coefficient in this interval is known to be: Solve the simultaneous heat balance equations The heat balance equation at a cooling water temperature of 40℃ is obtained by rearranging: .

[0087] Thus, a leak-proof water supply system model 3 based on the dynamic closed-loop coupling of "flow-friction-heat" was successfully constructed. This model establishes the optimal cross-sectional area of ​​the throttling valve orifice. The correlation with the impeller speed ω allows it to adapt to different speeds, thus effectively simulating the thermal balance of the actual hydropower unit's pressurized water phase adjustment system in maintaining the leak-proof ring.

[0088] It should be noted that the above-mentioned optimal cross-sectional area With rotational speed The mapping formula was derived under the premise that the cooling water temperature in the water supply pipe 9 of the leak-proof ring is 40℃. When the cooling water temperature varies within the common temperature range of 4-60℃, the mapping formula remains unchanged, only... The values ​​change. Because cooling water has different inherent physical properties at different temperatures, such as Prandtl number (Pr), kinematic viscosity (v), and thermal conductivity (λ), the values ​​of these three coefficients at each temperature are substituted into the calculation process of Example 4 and the processing flow of Example 6 to obtain the corresponding values. The specific calculation and processing of the value are the same as when the cooling water temperature is 40℃, and will not be repeated here.

[0089] Essentially, the ultimate goal of this invention is to determine an optimal flow rate. However, due to optimal flow... It cannot be directly controlled; in practice, the optimal cross-sectional area of ​​the throttle valve orifice is adjusted. To indirectly achieve traffic The adjustment is as follows. Therefore, the solution sequence is: first, through iterative calculation, determine the speed of the impeller that satisfies the current impeller speed. Optimal flow rate to achieve thermal equilibrium Then based on the optimal flow The relationship between the cross-sectional area and the required optimal cross-sectional area can be used to deduce the optimal cross-sectional area. Optimal traffic With the optimal cross-sectional area Substituting the formula into the friction coefficient equation, and then further substituting it into the heat balance equation to solve the simultaneous equations, we can establish the optimal cross-sectional area. With the rotational speed The mapping relationship between them.

Claims

1. A simulation method for a pressurized water phase regulation system of a hydropower unit, characterized in that, Includes the following steps: S1. Analyze and extract parameters of the pressurized water phase regulation system to be configured for the hydropower unit, and build the first framework, the second framework and the third framework; S2. Based on the water level in the runner chamber, a turbine model under different phase adjustment conditions is constructed within the first frame (5). S3. Set different rotational speeds ω of the turbine runner in the turbine model (5), and determine the optimal flow rate of the water supply pipeline based on the leak-proof ring. Using Bernoulli's equation, the optimal cross-sectional area of ​​the throttle valve orifice for different rotational speeds ω is obtained. ; Based on the water supply pipeline flow rate of the leak-proof ring The size is used to divide the contact friction state between the sealing ring and the impeller into different lubrication zones, and an optimal cross-sectional area is established based on the different lubrication zones. The mapping relationship with rotational speed ω; and then, based on the mapping relationship, a leak-proof ring water supply system model adapted to different rotational speeds ω is constructed within the second framework (3). S4. Based on the water level in the turbine chamber of the turbine model (5), establish the relationship between water level and runner chamber air leakage time, and the optimal flow rate of the leak-proof ring water supply pipeline. Based on the relationship, and combined with the hydraulic system and pneumatic system in the pressurized water phase adjustment system, an air-pressurized water gas-liquid mixing system model is constructed within the third framework (4). S5. Build a control system (6) and connect the control system (6) with the detection element and action element in the leak-stop ring water supply system model (3), the action element in the air-pressurized water gas-liquid mixing system model (4), and the detection element and action element in the water turbine model (5) to realize the signal acquisition of the detection element and the action control of the action element, and complete the simulation of the pressurized water phase adjustment system.

2. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 1, characterized in that, In step S3, the optimal cross-sectional area The method for establishing the mapping relationship with rotational speed ω includes the following steps: S3.1, Based on flow rate The coefficient of friction is listed for different lubrication ranges. Calculate the equation; S3.2, Based on the coefficient of friction Pressure of the leak-proof ring on the impeller Diameter at the contact point between the rotating wheel and the leak-proof ring List the flow rate based on the impeller speed ω. Heat generation of the lower sealing ring equation; S3.

3. Based on the basic forced convection heat transfer formula, list the flow rate. Heat dissipation of the lower sealing ring equation; S3.4, Heat generated during the construction of the leak-proof ring With heat dissipation The heat balance equation makes ; S3.

5. Based on the heat balance equation, iteratively solve for the optimal flow rate of the leak-proof ring water supply pipeline. ; S3.6, Based on optimal flow The optimal cross-sectional area of ​​the throttle valve orifice is obtained. ; S3.7, Based on the coefficient of friction Calculation equations, heat balance equations, and optimal flow rates Establish the optimal cross-sectional area The mapping relationship with rotational speed ω.

3. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 2, characterized in that, In step S3, the different lubrication zones include a boundary lubrication zone, a mixed lubrication zone, and a fluid lubrication zone. When the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is the boundary lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the fluid lubrication range; when the flow rate meets the requirements... At that time, the contact friction state between the sealing ring and the impeller is in the mixed lubrication range; among which, This is the critical flow rate for transitioning from the boundary lubrication zone to the mixed lubrication zone; This is the critical flow rate required to transition from the mixed lubrication zone to the fluid lubrication zone.

4. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 3, characterized in that, In step S3.1, the coefficient of friction The calculation equation is: ， In the formula, The coefficient of dry friction is The slope of the decreasing coefficient of friction for boundary lubrication. For mixed lubrication friction coefficient, The slope of the decreasing friction coefficient for mixed lubrication. is the coefficient of friction for fluid lubrication.

5. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 4, characterized in that, In step S3.5, the optimal flow rate is iteratively solved. The method includes the following steps: a. Select initial flow rate and make traffic =Initial flow ; b. Determine the flow rate The lubrication range in which the friction coefficient is determined And based on the determined coefficient of friction Substitute the heat output Equations for calculating flow rates The heat generated below ; c. Based on heat dissipation Equations for calculating flow rates Heat dissipation of the lower sealing ring ; d. Comparison of calorific value and heat dissipation If heat generation > Heat dissipation Increase the flow rate And return to step b; if heat generation Heat dissipation Then reduce the flow rate. And return to step b; e. Repeat steps a to d until the heat balance equation is satisfied. And the temperature of the leak-proof ring wall surface ≤ Maximum allowable temperature of the leak-proof ring sealing material The flow rate at this time That is, the optimal flow rate .

6. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 4, characterized in that, In step S3.2, the heat generation The equation is: ， In the formula, The pressure of the stop-leak ring on the impeller.

7. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 5, characterized in that: In step S3.3, the basic forced convection heat transfer calculation formula is: ， In the formula, h is the convective heat transfer coefficient, with units of W / (m²). K), convective heat transfer coefficient h and flow rate Related; The effective heat exchange area between the cooling water and the leak-proof ring, in units of ; This refers to the heat exchange temperature difference, expressed in Kelvin (K). That is, the temperature of the leak-proof ring wall surface With average cooling water temperature The difference; the heat exchange temperature difference Substituting into the basic forced convection heat transfer formula, we obtain the heat dissipation. The equation is: ， In the formula, To prevent leakage, the flow rate of the water supply pipeline The convective heat transfer coefficient below.

8. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 7, characterized in that: Under the premise that the temperature of the cooling water in the water supply pipeline of the leak-proof ring is 40℃, and using the Dittus-Boelter equation, the following calculations were performed: ， In the formula, The cross-sectional area of ​​the water flow at the contact point between the leak-stop ring and the impeller.

9. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 8, characterized in that, In step e, based on the heat balance equation, the simultaneous heat balance equations are obtained as follows: ， In the formula, .

10. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 9, characterized in that, In step S3.6, the optimal cross-sectional area of ​​the throttle valve orifice... The method for obtaining the value is as follows: using the inlet and outlet sections of the throttle valve as the calculation sections, the following Bernoulli equation is derived: ， Based on the assumed conditions, the optimal flow rate of the water supply pipeline for the leak-proof ring was derived. Optimal cross-sectional area of ​​throttle valve orifice The relation is: ， The combined assumption is that the flow velocities at the inlet and outlet sections of the throttle valve are approximately equal, i.e. The inlet and outlet cross-sectional heights of the throttle valve are equal. ; In the formula, The flow coefficient of the throttle valve. The constant pressure difference between the inlet and outlet of the throttle valve is , The pressure at the inlet section of the throttle valve. The pressure at the outlet section of the throttle valve. Where is the fluid density, and g is the acceleration due to gravity. The flow velocity at the inlet section of the throttle valve is... The velocity at the outlet section of the throttle valve is... The height of the throttle valve inlet section. This refers to the height of the outlet section of the throttle valve.

11. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 10, characterized in that, In step 3.7, the optimal cross-sectional area The mapping relationship with rotational speed ω is as follows: ， In the formula, , .

12. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 1, characterized in that: In step S4, the water level height, the air leakage time in the impeller chamber, and the optimal flow rate of the water supply pipeline for the leak-proof ring are considered. The relationship is as follows: ， In the formula, H is the water level in the runner chamber, and t is the air leakage time in the runner chamber. This refers to the leakage flow rate of the cooling water in the turbine chamber. The equivalent cross-sectional area of ​​the runner chamber and the runner chamber cooling water leakage flow rate. Equivalent cross-sectional area of ​​the turbine chamber All are set to constant values.

13. The simulation method for a hydropower unit pressurized water phase regulation system according to claim 1, characterized in that: In step S5, the actuating elements in the leak-stop ring water supply system model (3) include an upper leak-stop ring check valve (24), a lower leak-stop ring check valve (25), a throttle valve (28), a leak-stop ring electric ball valve (30), and a leak-stop ring check valve (32). The detection elements include an upper leak-stop ring flow meter (26), a lower leak-stop ring flow meter (27), and a leak-stop ring pressure gauge (31). The actuating elements in the pneumatic pressurized water gas-liquid mixing system model (4) include a pneumatic throttle valve (14), a pneumatic... Hydraulic valve (20), air-filling solenoid directional valve (23), air-filling check valve (34), air-filling hydraulic valve (19), air-filling solenoid directional valve (22), air-filling check valve (33), air-filling throttle valve (35), exhaust throttle valve (16), exhaust electric ball valve (17), exhaust hydraulic valve (18) and exhaust solenoid directional valve (21); the actuating element in the turbine model (5) includes the runner (38), and the detection element includes the level gauge (36) connected to the tailrace pipe.

14. A simulation method for a hydropower unit pressurized water phase regulation system according to any one of claims 1-13, characterized in that, The simulation method further includes: Step S6: Build a visual operation interface (1). The visual operation interface (1) communicates with the leak-stop ring water supply system model (3), the air-pressurized water gas-liquid mixing system model (4), the water turbine model (5), and the control system (6) to realize the phase adjustment condition conversion, real-time monitoring, interactive operation, and status warning of the pressurized water phase adjustment system simulation.

Images