Method for determining a multi-stage turbine blade throat area tolerance

Abstract

A method for determining a throat area tolerance of a multistage turbine blade, a computer device and a computer readable storage medium are provided for determining a throat area tolerance of a multistage turbine blade. The method for determining a throat area tolerance of a multistage turbine blade comprises the steps of: S1. obtaining a performance parameter of a turbine and a target value range of the performance parameter; S2. obtaining a sensitivity result of the performance parameter with respect to a throat area of each stage of the turbine blade; S3. obtaining a mathematical model of a deviation of the performance parameter with respect to a deviation of the throat area of each stage of the turbine blade according to the sensitivity result; S4. obtaining a tolerance of the throat area of each stage of the turbine blade; S5. performing a random error analysis according to the mathematical model, and counting a deviation distribution of the performance parameter when the deviation of the throat area of each stage of the turbine blade is randomly distributed within the tolerance; and S6. judging whether the deviation distribution is within the target value range, and if yes, outputting the tolerance, and if not, executing the step S4.

Description

Technical Field

[0001] This invention relates to the field of turbine engine design technology, specifically to a method for determining the throat area tolerance of multi-stage turbine blades, a computer device, and a computer-readable storage medium. Background Technology

[0002] The turbine blades and their adjacent blades, along with the upper and lower edge plates, form a relatively independent airflow channel. The minimum cross-section of this channel is the turbine blade throat (e.g., ...). Figure 1 As shown, the turbine blade throat area is a complex three-dimensional curved surface. The throat area of ​​the turbine blade is a key geometric parameter of the turbine, significantly influencing the operating characteristics of the turbine engine and consequently the performance of various components in the turbine engine's operating environment. Given a fixed overall performance parameter, turbine designers need to rationally design the throat area of ​​each stage of the turbine blade to optimize the operating performance of the turbine and the turbine engine.

[0003] Due to manufacturing and assembly deviations, the actual turbine blade throat area often deviates from the design target. For turbine engines, this deviation can cause various components to operate in undesigned conditions. For multi-stage turbines, this deviation can cause turbine performance to deviate from the design, reducing aerodynamic efficiency and operational reliability.

[0004] Currently, in engineering practice, turbine blade dimensional tolerance requirements are generally proposed based on the turbine blade's processing and manufacturing capabilities, but the requirements for turbine blade throat area tolerances are not clearly defined. Summary of the Invention

[0005] The purpose of this invention is to provide a method, computer device, and computer-readable storage medium for determining the throat area tolerance of multi-stage turbine blades.

[0006] In a first aspect, the present invention provides a method for determining the tolerance of the throat area of ​​a multi-stage turbine blade. According to an embodiment of the present invention, the method for determining the tolerance of the throat area of ​​a multi-stage turbine blade includes the following steps: S1. Obtaining the performance parameters of the turbine and the target numerical range of the performance parameters; S2. Obtaining the sensitivity results of the performance parameters as the throat area of ​​each stage of the turbine blade changes; S3. Obtaining a mathematical model of the performance parameters as the deviation of the throat area of ​​each stage of the turbine blade changes according to the sensitivity results; S4. Obtaining the tolerance of the throat area of ​​each stage of the turbine blade; S5. Performing random error analysis according to the mathematical model, and statistically analyzing the deviation distribution of the performance parameters when the deviation of the throat area of ​​each stage of the turbine blade is randomly distributed within the tolerance; and S6. Determining whether the deviation distribution is within the target numerical range. If yes, the tolerance is output; otherwise, step S4 is executed.

[0007] In one or more embodiments, in step S1, the performance parameters include turbine flow rate, turbine efficiency, turbine blade interstage pressure, and axial force within the flow channel.

[0008] In one or more embodiments, step S2 includes using a full three-dimensional viscous flow field calculation and analysis method to obtain the sensitivity results.

[0009] In one or more embodiments, in step S4, the tolerance is a positive or negative tolerance, and the absolute values ​​of the upper and lower deviations of the tolerance are equal.

[0010] In one or more embodiments, in step S5, the random distribution of the deviation of the throat area of ​​each turbine blade at each stage within the tolerance is a normal distribution, the mean of the deviation of the throat area of ​​each turbine blade at each stage is zero, and the standard deviation of the deviation of the throat area of ​​each turbine blade at each stage is one-third of the upper deviation of the tolerance.

[0011] In one or more embodiments, step S6 includes obtaining the standard deviation of the deviation distribution of the performance parameter, and determining whether the standard deviation plus or minus three times is within the target value range, so as to determine whether the deviation distribution is within the target value range.

[0012] Secondly, the present invention provides a computer device. According to an embodiment of the present invention, the computer device includes a processor and a memory. The memory stores a computer program, and the processor is used to run the computer program in the memory to implement the steps in the above-described method for determining the throat area tolerance of multi-stage turbine blades.

[0013] Thirdly, the present invention provides a computer-readable storage medium, wherein, according to an embodiment of the present invention, the computer-readable storage medium stores a plurality of instructions, which are adapted for loading by a processor to execute the steps in the above-described method for determining the throat area tolerance of multi-stage turbine blades.

[0014] The embodiments of the present invention have at least the following beneficial effects:

[0015] Based on the sensitivity relationship between performance parameters and the throat area of ​​turbine blades at each stage, a mathematical model is established to show the variation of performance parameters with the deviation of the throat area of ​​turbine blades at each stage. The deviation distribution of performance parameters is obtained by using random error analysis. Based on the deviation requirements of performance parameters, the throat area tolerance of turbine blades at each stage is obtained by iterative optimization. Attached Figure Description

[0016] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0017] Figure 1This is a schematic diagram of the turbine blade throat.

[0018] Figure 2 A flowchart illustrating the method for determining the throat area tolerance of multi-stage turbine blades;

[0019] Figure 3 The results show the sensitivity of turbine flow rate to changes in the throat area of ​​the second-stage guide vane.

[0020] Figure 4 The results show the sensitivity of the interstage pressure of the first-stage guide vane and the first-stage moving vane to the change in throat area of ​​the second-stage guide vane.

[0021] Figure label:

[0022] 1- Turbine blade;

[0023] 2- Turbine blade throat. Detailed Implementation

[0024] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0025] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0026] The terms “first”, “second”, etc., can be used interchangeably to distinguish one feature from another.

[0027] like Figure 1 As shown, the two adjacent turbine blades 1 and their upper and lower edge plates form a relatively independent airflow channel, the smallest cross-section of which is the turbine blade throat 2, a complex three-dimensional curved surface in space. The turbine blade 1 can be a guide vane mounted on the stator, with the turbine blade throat 2 between them forming the guide vane throat. Alternatively, the turbine blade 1 can be a moving blade mounted on the rotor, with the turbine blade throat 2 between them forming the moving blade throat. The area of ​​the turbine blade throat is the minimum cross-sectional area of ​​the airflow channel. Figure 1 It is shown in dashed lines.

[0028] like Figure 2As shown, the method for determining the tolerance of the throat area of ​​a multi-stage turbine blade includes step S1: obtaining the turbine's performance parameters and the target numerical range of these parameters. The turbine blade throat area determines the turbine's flow capacity, interstage pressure, and interstage temperature. Interstage pressure and temperature further affect turbine blade cooling, rim sealing between rotor and stator blades, and the rotor's axial force. The design of the turbine blade throat area must achieve the desired turbine flow capacity and optimize the distribution of interstage pressure and temperature. Deviations in the turbine blade throat area from the design target will deteriorate the interstage pressure and temperature distribution, causing the turbine's aerodynamic performance to deviate from the design. It will also lead to a reduction in the cooling airflow to the turbine blades or an increased risk of backflow into the rotor-stator rim sealing, reducing the turbine's aerodynamic efficiency and operational reliability. Therefore, determining the tolerance of the throat area of ​​a multi-stage turbine blade is a multi-objective optimization problem that needs to consider aerodynamic performance, blade cooling, rim sealing, and rotor load. Therefore, performance parameters may include turbine flow rate, turbine efficiency, interstage pressure, and axial force within the flow channel. The interstage pressure of a turbine blade is the average static pressure between two stages of turbine blades, for example, the average static pressure between the first-stage guide vane and the first-stage moving blade, or the average static pressure between the first-stage moving blade and the second-stage guide vane. The axial force within the flow channel is the axial component of the resultant force of the airflow acting on the moving blade. The turbine can be a two-stage turbine, comprising a first-stage guide vane, a first-stage moving blade, a second-stage guide vane, and a second-stage moving blade. The target value ranges for each performance parameter of the two-stage turbine are shown in Table 1. The target value range for turbine flow rate is 99% to 101% of its target value; the target value range for turbine efficiency is 99.8% to 100% of its target value; the target value range for interstage pressure of the first-stage guide vane and the first-stage moving vane is 97% to 103% of its target value; the target value range for interstage pressure of the first-stage moving vane and the second-stage guide vane is 97% to 103% of its target value; the target value range for interstage pressure of the second-stage guide vane and the second-stage moving vane is 97% to 103% of its target value; and the target value range for axial force in the flow channel is 95% to 105% of its target value.

[0029] Table 1. Target numerical range of various performance parameters of the two-stage turbine

[0030]

[0031] like Figure 2 As shown, the method for determining the throat area tolerance of multi-stage turbine blades also includes step S2: obtaining the sensitivity results of performance parameters as a function of the throat area of ​​each stage of the turbine blades. The sensitivity results of each performance parameter as a function of the throat area of ​​each stage of the turbine blades can be obtained using a full three-dimensional viscous flow field calculation and analysis method. Figure 3The results show the sensitivity of turbine flow rate of a two-stage turbine to changes in the throat area of ​​the second-stage guide vane. Figure 4 The sensitivity results for the interstage pressure of the first-stage guide vane and the first-stage moving vane of a two-stage turbine are shown as a function of the throat area of ​​the second-stage guide vane. Graphs showing the sensitivity results of other performance parameters as a function of the throat area of ​​each turbine blade are omitted.

[0032] like Figure 2 As shown, the method for determining the throat area tolerance of multi-stage turbine blades also includes step S3. Based on the sensitivity results, a mathematical model is obtained showing how performance parameters change with the deviation of the throat area of ​​each stage of the turbine blade. The mathematical model can be:

[0033] Δw=f1(Δa1)+f2(Δa2)+f3(Δa3)+…+f i (Δa i )

[0034]

[0035] Δp=φ1(Δa1)+φ2(Δa2)+φ3(Δa3)+…+φ i (Δa i )

[0036] Δfa=χ1(Δa1)+χ2(Δa2)+χ3(Δa3)+…+χ i (Δa i )

[0037] Where Δw is the turbine flow rate deviation. Δη is the turbine efficiency deviation. Δp is the inter-stage pressure deviation of a certain turbine blade. Δfa is the axial force deviation within the flow channel. i represents the i-th row of turbine blades. For a two-stage turbine, i = 1, 2, 3, 4, where i = 1 represents the first row of turbine blades (i.e., the first-stage guide vane), i = 2 represents the second row of turbine blades (i.e., the first-stage moving blade), i = 3 represents the third row of turbine blades (i.e., the second-stage guide vane), and i = 4 represents the fourth row of turbine blades (i.e., the second-stage moving blade). Δa i f represents the deviation of the throat area of ​​the i-th row of turbine blades from the design value. i Let be the sensitivity function for the effect of the change in the throat area of ​​the i-th row of turbine blades on the turbine flow rate. The sensitivity function is obtained from the sensitivity results in step S2. φ is the sensitivity function for the effect of the throat area change of the i-th row of turbine blades on turbine efficiency. This sensitivity function is obtained from the sensitivity results in step S2. i χ is the sensitivity function for the effect of the change in the throat area of ​​the i-th row of turbine blades on the interstage pressure of a certain turbine blade. The sensitivity function is obtained from the sensitivity results in step S2. i The sensitivity function of the effect of the change in the throat area of ​​the i-th row of turbine blades on the axial force in the flow channel is obtained from the sensitivity results of step S2.

[0038] like Figure 2 As shown, the method for determining the throat area tolerance of multi-stage turbine blades also includes step S4: obtaining the tolerance of the throat area of ​​each stage of turbine blades. The tolerance of the throat area of ​​each stage of turbine blades is the allowable deviation range of the throat area of ​​each stage of turbine blades relative to the design value. The selected tolerance of the throat area of ​​each stage of turbine blades can be positive or negative, and the absolute values ​​of the upper and lower deviations of the tolerance are equal.

[0039] like Figure 2 As shown, the method for determining the tolerance of the throat area of ​​multi-stage turbine blades also includes step S5. Based on the mathematical model, random error analysis is performed to statistically analyze the deviation distribution of performance parameters when the deviation of the throat area of ​​each stage of turbine blades is randomly distributed within the tolerance. It can be assumed that the random distribution of the deviation of the throat area of ​​each stage of turbine blades within the tolerance is a normal distribution, the mean μ of the deviation of the throat area of ​​each stage of turbine blades is zero, and the standard deviation σ of the deviation of the throat area of ​​each stage of turbine blades is one-third of the upper deviation of the tolerance selected in step S4, that is, the tolerance selected in step S4 is ±3σ. According to the 3σ principle of normal distribution, this ensures that the deviation of the throat area of ​​each stage of turbine blades has a 99.73% probability of falling within the selected tolerance. The code can be written using MATLAB or Python software to execute this method.

[0040] The throat areas of turbine blades at each stage follow a normal distribution. The deviation Δa of the throat area of ​​each stage of turbine blades is randomly obtained for the nth time. 1n , Δa 2n 、…、Δa in , where Δa i As mentioned before, n represents the nth random data, that is, the number of cycles n. The maximum value of n can be m, and n = 1, 2, 3, ... m. The deviation Δa of the throat area of ​​each turbine blade is... 1n , Δa 2n 、…、Δa in Substituting the mathematical model from step S3, the deviation Δw of each performance parameter is calculated. n , Δη n Δp n Δfa n The relevant meanings are as described above, and the cycle is as follows:

[0041] The number of iterations is n=1. In the first iteration, the deviation Δa of the throat area of ​​each turbine blade is randomly obtained. 11 , Δa 21 、…、Δa i1 Substitute these values ​​into the mathematical model of step S3 to calculate the deviations of each performance parameter: Δw1, Δη1, Δp1, and Δfa1.

[0042] The number of iterations is n=2. In the second iteration, the deviation Δa of the throat area of ​​each turbine blade stage is randomly obtained. 12 , Δa 22 、…、Δa i2 Substitute these values ​​into the mathematical model of step S3 to calculate the deviations of each performance parameter: Δw2, Δη2, Δp2, and Δfa2.

[0043] ...

[0044] The number of iterations η = m, and the deviation Δa of the throat area of ​​each turbine blade is randomly obtained in the m-th iteration. 1m , Δa 2m 、…、Δa im Substituting the values ​​into the mathematical model from step S3, the deviation Δw of each performance parameter is calculated. m , Δη m Δp m Δfa m ;

[0045] The process concludes by obtaining the deviations of each performance parameter in group m, and then obtaining the deviation distribution of the performance parameters when the deviation of the throat area of ​​each turbine blade is randomly distributed within the tolerance.

[0046] like Figure 2 As shown, the method for determining the throat area tolerance of multi-stage turbine blades also includes step S6: determining whether the deviation distribution is within the target value range. If yes, the tolerance is output; otherwise, step S4 is executed. The standard deviation of the deviation distribution of performance parameters can be obtained, and it is determined whether plus or minus three times the standard deviation is within the target value range to determine whether the deviation distribution is within the target value range. Taking the turbine flow deviation as an example, the deviations Δw1, Δw2, ..., Δw of the m sets of turbine flow obtained in step S5 are calculated. m The standard deviation S is compared with ±3S to the target value range of turbine flow rate in step S1. If ±3S is included in the target value range of turbine flow rate, the deviation distribution of turbine flow rate is within its target value range. If ±3S is not included in the target value range of turbine flow rate, the deviation distribution of turbine flow rate is not within its target value range. This method is used to iterate through all performance parameters, determining whether the deviation distribution of each performance parameter is within its target value range. If the deviation distribution of each performance parameter is within its target value range, the tolerance in step S4 meets the requirements of each performance parameter, and the tolerance in step S4 is output and the process ends. If some or all of the deviation distribution of each performance parameter is not within its target value range, the tolerance in step S4 does not meet the requirements of each performance parameter. Step S4 is executed again to obtain a new tolerance, and steps S5 and S6 are executed based on the new tolerance. The new tolerance obtained by executing step S4 again can be smaller than the tolerance obtained in the previous execution of step S4, so that the deviation distribution in step S6 is more likely to be within the target value range.

[0047] The method for determining the throat area tolerance of multi-stage turbine blades is used to determine the throat area tolerance of each stage of turbine blades in a multi-stage turbine. The tolerance requirements are implemented in the drawings of turbine blade castings and parts, controlling the throat area of ​​turbine blades from the source of design and manufacturing. This facilitates the control of the deviation of the throat area of ​​turbine blades from the design value, reduces the adverse effects of the deviation of the throat area of ​​turbine blades from the design value on the performance and reliability of turbine engines, and reduces the non-uniformity of the throat area of ​​the entire ring turbine blades.

[0048] A computer device includes a processor and a memory, the memory storing a computer program, and the processor running the computer program in the memory to implement the steps in the above-described method for determining the throat area tolerance of multi-stage turbine blades.

[0049] A computer-readable storage medium storing a plurality of instructions adapted for loading by a processor to perform the steps in the above-described method for determining the throat area tolerance of a multi-stage turbine blade.

[0050] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0051] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or through a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0052] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention.

Claims

1. A method for determining the throat area tolerance of a multi-stage turbine blade, characterized in that... include: Step S1. Obtain the turbine's performance parameters and the target range of these parameters; Step S2. Obtain the sensitivity results of the performance parameters as the throat area of ​​each turbine blade changes; Step S3. Based on the sensitivity results, obtain a mathematical model of how the performance parameters change with the deviation of the throat area of ​​each turbine blade stage; Step S4. Obtain the tolerance of the throat area of ​​each stage of turbine blades; Step S5. Based on the mathematical model, perform random error analysis to statistically analyze the deviation distribution of the performance parameters when the deviation of the throat area of ​​each stage of turbine blades is randomly distributed within the tolerance; and Step S6. Determine whether the deviation distribution is within the target value range. If yes, output the tolerance; otherwise, execute step S4.

2. The method for determining the throat area tolerance of multi-stage turbine blades according to claim 1, characterized in that: In step S1, the performance parameters include turbine flow rate, turbine efficiency, turbine blade interstage pressure, and axial force within the flow channel.

3. The method for determining the throat area tolerance of multi-stage turbine blades according to claim 1, characterized in that: Step S2 includes using a full three-dimensional viscous flow field calculation and analysis method to obtain the sensitivity results.

4. The method for determining the throat area tolerance of multi-stage turbine blades according to claim 1, characterized in that: In step S4, the tolerance is a positive or negative tolerance, and the absolute values ​​of the upper and lower deviations of the tolerance are equal.

5. The method for determining the throat area tolerance of multi-stage turbine blades according to claim 4, characterized in that: In step S5, the random distribution of the deviation of the throat area of ​​each turbine blade is normal within the tolerance, the mean of the deviation of the throat area of ​​each turbine blade is zero, and the standard deviation of the deviation of the throat area of ​​each turbine blade is one-third of the upper deviation of the tolerance.

6. The method for determining the throat area tolerance of multi-stage turbine blades according to claim 1, characterized in that: Step S6 includes obtaining the standard deviation of the deviation distribution of the performance parameter, and determining whether the standard deviation plus or minus three times is within the target value range, so as to determine whether the deviation distribution is within the target value range.

7. A computer device, characterized in that: The computer device includes a processor and a memory, the memory storing a computer program, and the processor running the computer program in the memory to implement the steps in the method for determining the throat area tolerance of a multi-stage turbine blade according to any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a plurality of instructions adapted for loading by a processor to perform the steps in the method for determining the throat area tolerance of a multi-stage turbine blade according to any one of claims 1 to 6.

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