A gas turbine cooling air distribution method based on counterflow margin optimization

Abstract

The application discloses a kind of air-cooled turbine cold air distribution method based on counterflow margin optimization, the air-cooled turbine cold air distribution method includes: by original and without air-cooled turbine three-dimensional simulation calculation each air film hole counterflow margin;Search the invalid chamber with margin less than 1, proportionally reduce the flow of remaining chamber and iterate until the whole chamber margin meets the standard;Evaluate wall temperature, increase / decrease the amount of cold air for failure / surplus area and iterate, finally eliminate local failure and surplus under the condition that the total amount of cold air does not change.The application is no longer limited to the complex modification of cooling structure itself, but based on the existing cold air distribution situation, introduces air film hole counterflow margin as the core evaluation index.Through investigation and positioning cooling failure area with substandard counterflow margin, calculate the cold air amount of the remaining standard chamber, and accordingly, accurately redistribute the cold air.In the iteration process, the wall temperature distribution is considered simultaneously until the counterflow margin and the wall temperature meet the design requirements.

Description

Technical Field

[0001] This invention relates to the field of cooling design technology for hot-end components of aero-engine turbines, and in particular to a method for cooling gas distribution in an air-cooled turbine based on counterflow margin optimization. Background Technology

[0002] Aero-engine hot-end components operate in extreme high-temperature environments for extended periods, and their long-term operation heavily relies on complex and sophisticated cooling technologies. Film cooling (FSU), a crucial component, forms an insulating film of cool gas on the turbine walls to resist the erosion of high-temperature combustion gases. However, FSU effectiveness is influenced by a combination of multiple parameters, particularly within the turbine's main flow path, where the cool gas exiting the film cooling orifices is subjected to strong unsteady sweeping by the complex potential field of the upstream blades. This complex flow environment easily leads to an imbalance in the distribution of cool gas: on the one hand, insufficient cool gas in some areas may cause instantaneous intrusion of high-temperature combustion gases, resulting in reduced cool gas outflow, cooling failure, or even ablation of the film cooling orifices; on the other hand, excess cool gas may exist in other chambers, ensuring local cooling efficiency but causing unnecessary mixing losses and severely limiting turbine efficiency improvements.

[0003] Currently, a cooling gas distribution strategy based on a one-dimensional pipe network model is widely adopted. This method analogizes cooling units such as film cooling holes, impact holes, and turbulence columns to circuit components, and thermal resistance to resistors, constructing a low-dimensional heat transfer model to improve computational speed. However, this model is based on a simplified Fourier heat transfer equation, making it difficult to accurately simulate the complex heat transfer conditions inside turbine blades. More importantly, traditional heat transfer design and aerodynamic design are decoupled. If the influence of complex flow structures such as secondary flow, upstream wake, and wave systems within the main flow channel is forcibly introduced during the design phase, the design difficulty will increase exponentially and the development cycle will be extended. Therefore, the initial cooling gas distribution scheme given by traditional methods is often not optimal and cannot effectively cope with the risk of local cooling failure caused by main flow disturbances. Specifically, the above technical route has three structural defects. First, the simplification mechanism of the one-dimensional pipe network model leads to prediction distortion. Because the model is based on idealized heat transfer assumptions, the actual heat transfer intensity, cool gas coverage, and mixing characteristics within turbine blades are far more complex than predicted by the model. Therefore, the cool gas distribution schemes developed accordingly have biases, with some chambers having insufficient cool gas and others having excessive cool gas, creating potential hazards for subsequent cooling failures. Secondly, the aerodynamic-heat transfer decoupling design ignores the mainstream interference effect. Secondary flows, wakes, and wave systems within the turbine flow channel inevitably strongly interfere with the cool gas coverage and evolution characteristics, exposing local film cooling holes to the risk of instantaneous intrusion of high-temperature combustion gases. Once combustion gases backflow, it will directly lead to a sharp reduction in cool gas outflow, localized cooling failure, and even catastrophic consequences such as film cooling hole ablation. Thirdly, existing technologies for addressing cooling failures often create a vicious cycle where solutions become increasingly complex. When localized cooling failures occur, designers typically employ composite cooling structures with more cooling units and more complex combinations, rather than optimizing the cool gas distribution relationship itself. This strategy of adding structure but not adjusting distribution, when encountering strong upstream disturbances and many interfering factors, not only greatly increases the iteration process and design difficulty, but also brings a series of secondary problems such as decreased reliability, complicated cold air flow path, and increased pressure loss along the flow path. Ultimately, it causes greater mixing losses and further weakens turbine efficiency. Summary of the Invention

[0004] This invention provides a method for air-cooled turbine cooling gas distribution based on counterflow margin optimization, which solves the technical problem that existing air-cooled turbine cooling gas distribution relies on a one-dimensional pipe network model and is decoupled from aerodynamic design, resulting in local film cooling failure under interference from mainstream secondary flow and upstream wake. Simply increasing the complexity of the cooling structure will exacerbate mixing losses and prolong the design cycle.

[0005] A method for distributing cool air to an air-cooled turbine based on counterflow margin optimization includes:

[0006] S1. Perform three-dimensional simulation calculations on the original air-cooled turbine and the non-air-cooled turbine without film cooling orifices and cooling chamber, respectively, and calculate the average total pressure of the flow rate at the outlet surface of each film cooling orifice. And the static pressure at the corresponding location under non-air-cooled conditions Obtain the backflow margin of each film gas pore. ;

[0007] S2. Search for the backflow margin of all film air holes. If there is a film air hole with a backflow margin of less than 1, locate the cold air chamber A where the non-compliant film air hole is located. Based on the backflow margin of other compliant chambers, increase the cold air volume of chamber A. Reduce the cold air volume of the remaining chambers proportionally according to the cold air volume distribution scheme of the prototype. Re-perform the simulation calculation and iterate until the backflow margin of all film air holes meets the standard.

[0008] S3. Once the counterflow margin meets the standard, evaluate the wall temperature. If there is a cooling failure area or an excess area, locate the cooling failure chamber and the excess cooling chamber, increase the cooling air volume for the cooling failure chamber, and decrease the cooling air volume for the excess cooling chamber proportionally. Re-perform the simulation calculation and iterate until there is no cooling failure and no excess cooling area to obtain the final cooling air distribution scheme.

[0009] Preferably, step S1 further includes the following sub-steps:

[0010] S101. Obtain the total pressure of the average flow rate at the outlet surface of each air film orifice. and static pressure at the corresponding position of the air-cooled turbine The "no-air-cooling condition" refers to sealing the film cooling holes and cooling chambers in the original air-cooled turbine model, leaving only the main flow channel for calculation, in order to obtain the static pressure distribution of the main flow on the blade surface under non-cooled conditions.

[0011] S102, from formula The countercurrent margin corresponding to each film pore was calculated. .

[0012] Preferably, step S2 further includes the following sub-steps:

[0013] S201. Locate the cold air chamber A containing the substandard film membrane orifice, and calculate the backflow margin corresponding to all orifices in this chamber. Assuming that the cold air distribution coefficient is consistent for orifices in the same radial row, distinguish and locate the radial and directional positions of the orifice rows containing the substandard film membrane orifice, and assign different cold air distribution coefficients for different directional positions. ( The cooling gas distribution coefficient on the leading edge side of the guide vane must be greater than the cooling gas distribution coefficient at other flow directions.

[0014] S202. Locate chambers B / C / D where other compliant air film vents are located, and calculate and evaluate the backflow margin of the compliant chambers. As can be seen from the expression for calculating flow rate, increasing or decreasing the airflow slightly will affect the total air pressure, further impacting the backflow margin. The expression for calculating flow rate is:

[0015]

[0016] in, This indicates the margin of total chamber pressure. Indicates mass flow rate. It is a constant, only related to the physical properties of the gas, and its calculation formula is: In the formula, k is the specific heat ratio of the gas, and R is the gas constant. For total temperature, Let q(Ma) represent the flow area, and q(Ma) be a dimensionless flow function.

[0017] S203, Increase the amount of cold air in chamber A. The remaining chambers have their cooling volume reduced proportionally according to the original cooling volume distribution scheme, with the total reduction in cooling volume being... ;

[0018] in, This indicates an estimated increase in cooling air volume for chamber A that does not meet the standards. Indicates the air conditioning distribution coefficient. For formula The constant in, This represents the reverse flow margin.

[0019] Preferably, step S2 further includes the following sub-steps:

[0020] S301. Once the counterflow margin meets the standard, evaluate the wall temperature to determine if there is any cooling failure or excess area: if the local wall temperature is > design temperature + 50K, it is determined to be cooling failure; if the local wall temperature is < design temperature - 50K, it is determined to be cooling excess; if there is a cooling failure or excess area, proceed to step S2 for iteration.

[0021] S302. Locate the excessive cooling and cooling failure chambers, statistically analyze the average wall temperature and local maximum temperature of the cooling failure chambers, and calculate the wall temperature margin of the excessive cooling chambers; during the iteration process, preset the initial cold air volume increment. Increase the amount of cold air in the cooling failure chamber. The cooling excess chamber reduces the amount of cooling air proportionally according to the original cooling air distribution scheme, ensuring that the total reduction in cooling air volume is... ;

[0022] S303. After the cooling air volume is redistributed, the simulation calculation boundary conditions are redefined, the simulation calculation is continued, and the results are analyzed. If there are unsatisfactory situations, the iteration continues until there are no failures or excess areas, and the final solution is obtained.

[0023] Preferably, the cooling distribution coefficient The value range is 1.05~1.30, which is the cold air distribution coefficient on the leading edge side of the guide vane. The value range is 1.20~1.30, and the cold air distribution coefficient for other airflow directions is... The value range is 1.05 to 1.15.

[0024] Preferably, the three-dimensional simulation calculation adopts the computational fluid dynamics (CFD) method to solve the Reynolds-averaged Navier-Stokes equations to obtain the flow field parameters.

[0025] In this invention, by introducing three-dimensional computational fluid dynamics simulation to replace the one-dimensional pipe network model, the flow field parameters are obtained by directly solving the Reynolds-averaged Navier-Stokes equations, and the counterflow margin of each film gas hole is accurately calculated. This fundamentally overcomes the problem of inaccurate distribution caused by model simplification in existing technologies. At the same time, with the counterflow margin as the core evaluation index, the invention actively identifies the cooling failure area under the interference of complex flow structures such as the mainstream secondary flow and wake, and performs dynamic redistribution of the cooling air volume based on the counterflow margin margin of the qualified chamber. This enables the cooling air distribution scheme to adaptively respond to upstream disturbances, significantly improving the anti-interference ability of complex flow environments.

[0026] This invention avoids the vicious cycle of increasing cooling structure complexity when encountering cooling failures, as is common in existing technologies. It restores cooling effectiveness simply by optimizing the distribution of cold air volume within the existing cooling structure: the incremental cold air volume is precisely calculated using a flow formula. This strategy involves proportionally transferring cooling resources from excess chambers to failure chambers without altering the cooling structure itself. This shifts the core of the design iteration from increasing structural complexity to optimizing resource allocation. This approach significantly shortens the design cycle and avoids a series of secondary problems associated with composite cooling structures, such as decreased reliability, increased complexity of cooling flow paths, and increased pressure loss along the flow path.

[0027] This invention constructs a two-stage iterative convergence mechanism of initial screening of counterflow margin and fine calibration of wall temperature. After the counterflow margin meets the standard, the wall temperature is further used as a second evaluation index, and a clear judgment threshold is set (the local area temperature of the wall is judged as cooling failure if it is greater than the design temperature + 50K, and as excessive cooling if it is less than the design temperature - 50K) for closed-loop verification. This makes the final solution not only eliminate the risks of sharp reduction in cold air output and blade ablation caused by high-temperature gas intrusion, but also suppress the mixing loss caused by excessive cold air. The counterflow margin distribution is more concentrated and reasonable (e.g., the maximum value is reduced from 2.4 in the original solution to about 2.2 in the optimized solution), and the synergistic optimization of cooling safety and aerodynamic efficiency is achieved. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a method for air-cooled turbine cooling gas distribution based on counterflow margin optimization in one embodiment of the present invention;

[0030] Figure 2 This is a comparison diagram of the original scheme and the change of the film film orifice counterflow margin over time in an embodiment of the present invention; wherein a is a schematic diagram of the change of the film film orifice counterflow margin over time in the original scheme; b is a schematic diagram of the change of the film film orifice counterflow margin over time in an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The air-cooled turbine air distribution method based on counter-flow margin optimization provided in this invention can be applied to, for example... Figure 1 The application environment is shown. Specifically, the air-cooled turbine air distribution method based on counter-flow margin optimization is applied in an air-cooled turbine air distribution method system based on counter-flow margin optimization, which includes, as shown... Figure 1The diagram illustrates a client and server that communicate over a network to implement a counterflow margin-optimized air-cooled turbine cooling distribution method (a supplementary function or problem-solving approach). The client, also known as the user terminal, is the program that provides local services to the client, corresponding to the server. The client can be installed on, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. The server can be a standalone server or a server cluster consisting of multiple servers.

[0033] Preferably, such as Figure 1 As shown, a method for distributing cool air to an air-cooled turbine based on counterflow margin optimization is provided, including the following steps:

[0034] S1. Perform three-dimensional simulation calculations on the original air-cooled turbine and the non-air-cooled turbine without film cooling orifices and cooling chamber, respectively, and calculate the average total pressure of the flow rate at the outlet surface of each film cooling orifice. And the static pressure at the corresponding location under non-air-cooled conditions Obtain the backflow margin of each film gas pore. .

[0035] In one embodiment, step S1 further includes the following sub-steps:

[0036] S101. Obtain the total pressure of the average flow rate at the outlet surface of each air film orifice. and static pressure at the corresponding position of the air-cooled turbine The "no-air-cooling condition" refers to sealing the film cooling holes and cooling chambers in the original air-cooled turbine model, leaving only the main flow channel for calculation, in order to obtain the static pressure distribution of the main flow on the blade surface under non-cooled conditions.

[0037] S102, from formula The countercurrent margin corresponding to each film pore was calculated. .

[0038] Understandably, by performing three-dimensional simulations on the original air-cooled turbine and the non-air-cooled turbine without film cooling orifices and cooling chambers, the reverse flow margin of each film cooling orifice is obtained, overcoming the limitations of existing technologies that rely on simplified predictions using one-dimensional pipe network models. Existing technologies employ a one-dimensional pipe network model based on a simplified Fourier heat transfer equation, analogizing complex cooling units to circuit elements for low-dimensional heat transfer calculations. This leads to significant deviations between the actual heat transfer intensity, cooling gas coverage, and mixing characteristics within the turbine blades and the model predictions. This invention introduces three-dimensional computational fluid dynamics simulation, directly solving the Reynolds-averaged Navier-Stokes equations to obtain flow field parameters. This accurately reflects the influence of complex flow structures such as secondary flow, upstream wake, and wave systems within the main flow channel on the outflow characteristics of the film cooling orifices, thereby precisely calculating the average total pressure at the outlet surface of each film cooling orifice and the corresponding static pressure, obtaining an accurate benchmark for assessing the reverse flow margin. This step provides a reliable data foundation for subsequent iterative optimization, avoiding the allocation inaccuracies caused by model simplification.

[0039] S2. Search for the backflow margin of all film air holes. If there is a film air hole with a backflow margin of less than 1, locate the cold air chamber A where the non-compliant film air hole is located. Based on the backflow margin of other compliant chambers, increase the cold air volume of chamber A. Reduce the cold air volume of the remaining chambers proportionally according to the cold air volume distribution scheme of the prototype. Re-perform the simulation calculation and iterate until the backflow margin of all film air holes meets the standard.

[0040] In one embodiment, step S2 further includes the following sub-steps:

[0041] S201. Locate the cold air chamber A containing the substandard film membrane orifice, and calculate the backflow margin corresponding to all orifices in this chamber. Assuming that the cold air distribution coefficient is consistent for orifices in the same radial row, distinguish and locate the radial and directional positions of the orifice rows containing the substandard film membrane orifice, and assign different cold air distribution coefficients for different directional positions. ( The cooling gas distribution coefficient on the leading edge side of the guide vane must be greater than the cooling gas distribution coefficient at other flow directions.

[0042] S202. Locate chambers B / C / D where other compliant air film vents are located, and calculate and evaluate the backflow margin of the compliant chambers. As can be seen from the expression for calculating flow rate, increasing or decreasing the airflow slightly will affect the total air pressure, further impacting the backflow margin. The expression for calculating flow rate is:

[0043]

[0044] in, This indicates the margin of total chamber pressure. Indicates mass flow rate. It is a constant, only related to the physical properties of the gas, and its calculation formula is: In the formula, k is the specific heat ratio of the gas, and R is the gas constant. For total temperature, Let q(Ma) represent the flow area, and q(Ma) be a dimensionless flow function.

[0045] S203, Increase the amount of cold air in chamber A. The remaining chambers have their cooling volume reduced proportionally according to the original cooling volume distribution scheme, with the total reduction in cooling volume being... .in, This indicates an estimated increase in cooling air volume for chamber A that does not meet the standards. Indicates the air conditioning distribution coefficient. For formula The constant in, This represents the reverse flow margin.

[0046] Understandably, by retrieving the backflow margin of all film cooling orifices, the cold air chamber A containing the non-compliant film cooling orifices is located. Based on the backflow margin of other compliant chambers, the amount of cold air in chamber A is increased, while the amount of cold air in the remaining chambers is proportionally reduced, thus achieving dynamic redistribution of cold air volume. This solves the problem of existing technologies lacking adaptability to mainstream interference. Existing technologies generally do not make adjustments after the cold air distribution scheme is fixed. When a local film cooling orifice experiences a backflow margin of less than 1 due to upstream disturbances, resulting in high-temperature combustion gas intrusion, a more complex composite cooling structure can only be passively adopted to cope. This invention uses backflow margin as the core evaluation index to actively identify cooling failure areas and quantifies the backflow margin of compliant chambers. Accurately calculate the increase in cooling air volume using the flow formula. This enables the precise transfer of cooling resources from excess chambers to inefficient chambers. Simultaneously, differentiated cooling distribution coefficients are applied to different flow directions. (Leading edge of the guide vane) (Greater than other locations), reflecting a strategy of prioritizing protection for the high-load area at the leading edge. This step does not require changes to the existing cooling structure; cooling effectiveness can be restored simply by optimizing the distribution of cold air volume. This significantly shortens the design iteration cycle and avoids the problems of decreased reliability and increased pressure loss along the flow path caused by structural complexity.

[0047] S3. Once the counterflow margin meets the standard, evaluate the wall temperature. If there is a cooling failure area or an excess area, locate the cooling failure chamber and the excess cooling chamber, increase the cooling air volume for the cooling failure chamber, and decrease the cooling air volume for the excess cooling chamber proportionally. Re-perform the simulation calculation and iterate until there is no cooling failure and no excess cooling area to obtain the final cooling air distribution scheme.

[0048] In one embodiment, step S3 further includes the following sub-steps:

[0049] S301. Once the counterflow margin meets the standard, evaluate the wall temperature to determine if there is any cooling failure or excess area: if the local wall temperature is > design temperature + 50K, it is determined to be cooling failure; if the local wall temperature is < design temperature - 50K, it is determined to be cooling excess; if there is a cooling failure or excess area, proceed to step S2 for iteration.

[0050] S302. Locate the excessive cooling and cooling failure chambers, statistically analyze the average wall temperature and local maximum temperature of the cooling failure chambers, and calculate the wall temperature margin of the excessive cooling chambers; during the iteration process, preset the initial cold air volume increment. Increase the amount of cold air in the cooling failure chamber. The cooling excess chamber reduces the amount of cooling air proportionally according to the original cooling air distribution scheme, ensuring that the total reduction in cooling air volume is... ;

[0051] S303. After the cooling air volume is redistributed, the simulation calculation boundary conditions are redefined, the simulation calculation is continued, and the results are analyzed. If there are unsatisfactory situations, the iteration continues until there are no failures or excess areas, and the final solution is obtained.

[0052] Understandably, after achieving the counterflow margin, the wall temperature is further evaluated. If cooling failure or excess areas exist, iterative optimization continues, achieving convergence under the dual constraints of aerodynamic safety and thermal protection effectiveness, ensuring that the final solution has neither cooling failure nor excess cooling. Existing technologies only consider the distribution of cold air or the complexity of the cooling structure as design goals, lacking closed-loop verification of the actual wall heat transfer effect. This may lead to local wall temperatures still exceeding the design allowable range, or excessive cold air causing unnecessary mixing losses. This invention introduces wall temperature as a second evaluation indicator, setting clear judgment thresholds (a local wall temperature > design temperature + 50K is judged as cooling failure, < design temperature - 50K is judged as excess cooling), and using preset cold air increments... A two-stage iterative mechanism was established, involving initial screening of the counterflow margin followed by fine-tuning of the wall temperature, to address both the failure chamber with increased cooling and the excess chamber with reduced cooling. This step ensured that the optimized design balanced cooling safety and aerodynamic efficiency: on the one hand, it eliminated the risks of sharp reduction in coolant flow and blade ablation caused by high-temperature combustion gas intrusion; on the other hand, it suppressed the mixing losses caused by excessive cooling, resulting in a more concentrated and reasonable distribution of the counterflow margin (e.g., the maximum value was reduced from 2.4 in the original design to approximately 2.2 in the optimized design), significantly improving turbine efficiency.

[0053] In one embodiment, the cooling distribution coefficient The value range is 1.05~1.30, which is the cold air distribution coefficient on the leading edge side of the guide vane. The value range is 1.20~1.30, and the cold air distribution coefficient for other airflow directions is... The value range is 1.05~1.15. Understandably, by setting a higher lower limit of the allocation coefficient (1.20) for the high-risk area of ​​the guide vane leading edge, which is most susceptible to unsteady sweeping by the mainstream and most prone to backflow of gas, the reverse flow margin of the key hot end is prioritized, effectively avoiding the risk of local ablation. Secondly, a relatively conservative coefficient range (1.05~1.15) is adopted for other flow directions, which, while meeting basic cooling requirements, suppresses the mixing loss caused by excessive injection of cold gas to the greatest extent and takes into account the aerodynamic efficiency of the turbine. Finally, the setting of this gradient numerical range provides a scientific and controllable adjustment benchmark for iterative optimization, avoids the blindness in the cold gas allocation process, and enables the algorithm to quickly converge to the optimal allocation scheme that has neither cooling failure nor overcooling.

[0054] In one embodiment, the three-dimensional simulation calculation employs computational fluid dynamics (CFD) to solve the Reynolds-averaged Navier-Stokes equations to obtain the flow field parameters.

[0055] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0056] Preferably, a counter-flow margin-optimized air-cooled turbine air distribution system is provided, which corresponds one-to-one with the counter-flow margin-optimized air-cooled turbine air distribution method described in the above embodiments. This counter-flow margin-optimized air-cooled turbine air distribution system includes:

[0057] The 3D simulation calculation module 100 is used to perform 3D simulation calculations on the original air-cooled turbine and the non-air-cooled turbine without film cooling orifices and cooling chambers, respectively, and to calculate the average total pressure of the flow rate at the outlet surface of each film cooling orifice. And the static pressure at the corresponding location under non-air-cooled conditions Obtain the backflow margin of each film gas pore. .

[0058] The counterflow margin iteration optimization module 200 is used to search for the counterflow margin of all film air holes. If there is a film air hole with a counterflow margin of less than 1, the cold air chamber A where the non-compliant film air hole is located is located. Based on the counterflow margin margin of other compliant chambers, the cold air volume of chamber A is increased. The cold air volume of the remaining chambers is reduced proportionally according to the cold air volume distribution scheme of the prototype. The simulation calculation is re-performed and iterated until the counterflow margin of all film air holes meets the standard.

[0059] The wall temperature iteration optimization module 300 is used to evaluate the wall temperature after the counterflow margin meets the standard. If there is a cooling failure area or an excess area, the cooling failure chamber and the excess cooling chamber are located. The cooling air volume is increased for the cooling failure chamber and the cooling air volume is reduced proportionally for the excess cooling chamber. The simulation calculation is re-performed and iterated until there is no cooling failure and no excess cooling area, and the final cooling air distribution scheme is obtained.

[0060] In a specific implementation, such as Figure 2 As shown in the figure, this diagram compares the evolution of the counterflow margin at each film gas orifice with unsteady time steps between the optimized scheme and the original scheme after iteration of this invention. The figure shows that in the original scheme, the counterflow margin of some film gas orifices drops below the critical value of 1.0 at specific times (such as time 0 and around time step 60) (corresponding to curves A and B in the figure), indicating that the cold gas outflow is obstructed at this time, posing a risk of high-temperature gas backflow and cooling failure. Simultaneously, the peak counterflow margin of some other film gas orifices reaches as high as 2.4, reflecting excessive cold gas supply, which will lead to unnecessary mixing losses.

[0061] In contrast, the scheme adjusted by the iterative optimization method described in this invention maintains a stable counterflow margin of over 1.0 for all film cooling vents throughout the entire unsteady cycle, completely eliminating the potential for localized cooling failure caused by mainstream interference. More importantly, the dispersion of each curve is significantly reduced after optimization, and the counterflow margin distribution is more concentrated, with its maximum value decreasing from the original 2.4 to approximately 2.2. This result strongly confirms the effectiveness of the cold air margin redistribution strategy of this invention: that is, while ensuring the anti-intrusion capability of the film cooling vents (… Under the premise of [missing information], the phenomenon of excess cooling air was significantly suppressed, and the cooling air resources were evenly distributed throughout the blade domain, achieving the best balance between cooling safety and aerodynamic performance.

[0062] Specific limitations regarding the air-cooled turbine air distribution system based on counter-flow margin optimization can be found in the limitations of the air-cooled turbine air distribution method based on counter-flow margin optimization mentioned above, and will not be repeated here. Each module in the aforementioned air-cooled turbine air distribution system based on counter-flow margin optimization can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0063] In one embodiment, a computer device is provided, which may be a server. The computer device includes a processor, memory, a network interface, and a database connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database is used for a counter-current margin-optimized air-cooled turbine air distribution method. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a counter-current margin-optimized air-cooled turbine air distribution method.

[0064] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above.

[0065] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for air cooling turbine cold air distribution based on counterflow margin optimization, characterized in that, include: S1, the original scheme of air-cooled turbine and no gas film hole, cold gas cavity without air cooling turbine, respectively, three-dimensional simulation calculation, calculation of each gas film hole exit surface flow average total pressure And the static pressure of the corresponding position under the condition of no air cooling , get each gas film hole backflow margin ; S2. Search for the backflow margin of all film air holes. If there is a film air hole with a backflow margin of less than 1, locate the cold air chamber A where the non-compliant film air hole is located. Based on the backflow margin of other compliant chambers, increase the cold air volume of chamber A. Reduce the cold air volume of the remaining chambers proportionally according to the cold air volume distribution scheme of the prototype. Re-perform the simulation calculation and iterate until the backflow margin of all film air holes meets the standard. S3. Once the counterflow margin meets the standard, evaluate the wall temperature. If there is a cooling failure area or an excess area, locate the cooling failure chamber and the excess cooling chamber, increase the cooling air volume for the cooling failure chamber, and decrease the cooling air volume for the excess cooling chamber proportionally. Re-perform the simulation calculation and iterate until there is no cooling failure and no excess cooling area to obtain the final cooling air distribution scheme.

2. The air-cooled turbine cooling gas distribution method based on counterflow margin optimization according to claim 1, characterized in that, Step S1 further includes the following sub-steps: S101. Obtain the total pressure of the average flow rate at the outlet surface of each air film orifice. and static pressure at the corresponding position of the air-cooled turbine The "no-air-cooling condition" refers to sealing the film cooling holes and cooling chambers in the original air-cooled turbine model, leaving only the main flow channel for calculation, in order to obtain the static pressure distribution of the main flow on the blade surface under non-cooled conditions. S102, from formula The countercurrent margin corresponding to each film pore was calculated. .

3. The air-cooled turbine cooling gas distribution method based on counterflow margin optimization according to claim 2, characterized in that, Step S2 further includes the following sub-steps: S201. Locate the cold air chamber A containing the substandard film membrane orifice, and calculate the backflow margin corresponding to all orifices in this chamber. Assuming that the cold air distribution coefficient is consistent for orifices in the same radial row, distinguish and locate the radial and directional positions of the orifice rows containing the substandard film membrane orifice, and assign different cold air distribution coefficients for different directional positions. ( The cooling gas distribution coefficient on the leading edge side of the guide vane must be greater than the cooling gas distribution coefficient at other flow directions. S202. Locate chambers B / C / D where other compliant air film vents are located, and calculate and evaluate the backflow margin of the compliant chambers. As can be seen from the expression for calculating flow rate, increasing or decreasing the airflow slightly will affect the total air pressure, further impacting the backflow margin. The expression for calculating flow rate is: ， in, This indicates the margin of total chamber pressure. Indicates mass flow rate. It is a constant, only related to the physical properties of the gas, and its calculation formula is: In the formula, k is the specific heat ratio of the gas, and R is the gas constant. For total temperature, Let q(Ma) represent the flow area, and q(Ma) be a dimensionless flow function. S203, Increase the amount of cold air in chamber A. The remaining chambers have their cooling volume reduced proportionally according to the original cooling volume distribution scheme, with the total reduction in cooling volume being... ;in, This indicates an estimated increase in cooling air volume for chamber A that does not meet the standards. Indicates the air conditioning distribution coefficient. For formula The constant in, This represents the reverse flow margin.

4. The air-cooled turbine cooling gas distribution method based on counterflow margin optimization according to claim 3, characterized in that, Step S3 further includes the following sub-steps: S301. Once the counterflow margin meets the standard, evaluate the wall temperature to determine if there is any cooling failure or excess area: if the local wall temperature is > design temperature + 50K, it is determined to be cooling failure; if the local wall temperature is < design temperature - 50K, it is determined to be cooling excess; if there is a cooling failure or excess area, proceed to step S2 for iteration. S302. Locate the excessive cooling and cooling failure chambers, statistically analyze the average wall temperature and local maximum temperature of the cooling failure chambers, and calculate the wall temperature margin of the excessive cooling chambers; during the iteration process, preset the initial cold air volume increment. Increase the amount of cold air in the cooling failure chamber. The cooling excess chamber reduces the amount of cooling air proportionally according to the original cooling air distribution scheme, ensuring that the total reduction in cooling air volume is... ; S303. After the cooling air volume is redistributed, the simulation calculation boundary conditions are redefined, the simulation calculation is continued, and the results are analyzed. If there are unsatisfactory situations, the iteration continues until there are no failures or excess areas, and the final solution is obtained.

5. The air-cooled turbine cooling gas distribution method based on counterflow margin optimization according to claim 3, characterized in that, The air distribution coefficient The value range is 1.05~1.30, which is the cold air distribution coefficient on the leading edge side of the guide vane. The value range is 1.20~1.30, and the cold air distribution coefficient for other airflow directions is... The value range is 1.05 to 1.

15.

6. The air-cooled turbine cooling gas distribution method based on counterflow margin optimization according to claim 1, characterized in that, The three-dimensional simulation calculation uses the computational fluid dynamics (CFD) method to solve the Reynolds-averaged Navier-Stokes equations to obtain the flow field parameters.

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