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

Abstract

The invention discloses a multistage turbine blade throat area tolerance determination method, computer equipment and a computer readable storage medium, which are used for determining the multistage turbine blade throat area tolerance. The method for determining the throat area tolerance of the multi-stage turbine blade comprises the steps that S1, performance parameters of a turbine and the target numerical range of the performance parameters are obtained; s2, obtaining a sensitivity result of the performance parameter along with the change of the throat area of each stage of turbine blade; s3, according to the sensitivity result, a mathematical model that the performance parameters change along with the deviation of the throat area of each stage of turbine blade is obtained; s4, the tolerance of the throat area of each stage of turbine blade is obtained; s5, according to the mathematical model, random error analysis is carried out, and the deviation distribution of the performance parameters when the deviation of the throat area of each stage of turbine blade is randomly distributed within the tolerance is counted; and S6, judging whether the deviation distribution is within the target value range or not, if so, outputting the tolerance, and if not, executing the step S4.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine engine design, and in particular to a method for determining a throat area tolerance of a multi-stage turbine blade, a computer device, and a computer-readable storage medium. Background Art

[0002] The adjacent blades and upper and lower edge plates on both sides of the turbine form a relatively independent airflow channel, the minimum cross section of which is the turbine blade throat (such as Figure 1 The turbine blade throat area is a key geometric parameter of the turbine, which greatly affects the working law of the turbine engine and further affects the performance of each component in the working environment of the turbine engine. Under the premise of determining the overall performance parameters, the turbine designer needs to reasonably design the turbine blade throat area at each level to optimize the working performance of the turbine and the turbine engine.

[0003] Due to processing and assembly deviations, the actual turbine blade throat area often deviates from the design target. For turbine engines, the deviation of the turbine blade throat area from the design target will cause the turbine engine components to operate in non-design conditions. For multi-stage turbines, the deviation of the turbine blade throat area from the design target will cause the turbine performance to deviate from the design, reducing the turbine's aerodynamic efficiency and operating reliability.

[0004] Currently, in engineering, the dimensional tolerance requirements of turbine blades are generally proposed from the perspective of the processing and manufacturing capabilities of turbine blades, but the tolerance requirements for the throat area of ​​turbine blades are unclear. Summary of the invention

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

[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 step S1. obtaining performance parameters of the turbine and target numerical ranges of the performance parameters; step S2. obtaining sensitivity results of the performance parameters with changes in throat areas of turbine blades at various stages; step S3. obtaining a mathematical model of the performance parameters with deviations of throat areas of turbine blades at various stages based on the sensitivity results; step S4. obtaining the tolerances of throat areas of turbine blades at various stages; step S5. performing random error analysis based on the mathematical model, and statistically analyzing the deviation distribution of the performance parameters when the deviations of throat areas of turbine blades at various stages are randomly distributed within the tolerance; and step S6. determining whether the deviation distribution is within the target numerical range, and if so, outputting the tolerance; if not, executing step S4.

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

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

[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 stage of turbine blades within the tolerance is a normal distribution, the mean of the deviation of the throat area of ​​each stage of turbine blades is zero, and the standard deviation of the deviation of the throat area of ​​each stage of turbine blades 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 plus or minus three times the standard deviation is within the target numerical range to determine whether the deviation distribution is within the target numerical range.

[0012] In a second aspect, 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. The processor is used to run the computer program in the memory to implement the steps in the above-mentioned method for determining the throat area tolerance of multi-stage turbine blades.

[0013] In a third aspect, the present invention provides a computer-readable storage medium. According to an embodiment of the present invention, the computer-readable storage medium stores a plurality of instructions, and the instructions are suitable for loading by a processor to execute the steps in the above-mentioned 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] According to the sensitivity relationship between the performance parameters and the throat area of ​​each stage of turbine blades, a mathematical model of the performance parameters changing with the deviation of the throat area of ​​each stage of turbine blades is established. The deviation distribution of the performance parameters is obtained by using the random error analysis method. According to the deviation requirements of the performance parameters, the throat area tolerance of each stage of turbine blades is obtained by iterative optimization. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0018] Figure 2 A flow chart of a method for determining the tolerance of throat area of ​​a multi-stage turbine blade;

[0019] Figure 3 is the sensitivity result of the turbine flow rate with the change of the throat area of ​​the second-stage guide vane;

[0020] Figure 4 is the sensitivity result of the interstage pressure of the first-stage guide vane and the first-stage moving blade with the change of the throat area of ​​the second-stage guide vane;

[0021] Reference numerals:

[0022] 1- Turbine blades;

[0023] 2-Turbine blade throat. DETAILED DESCRIPTION

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

[0025] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0026] The terms "first", "second", etc. may be used interchangeably to distinguish one feature from another.

[0027] like Figure 1 As shown, the turbine blades 1 and the upper and lower edge plates adjacent to each other on both sides of the turbine form a relatively independent airflow channel, whose minimum cross-section is the turbine blade throat 2, which is a complex three-dimensional surface in space. The turbine blade 1 can be a guide vane installed on the stator, and the turbine blade throat 2 between them is the guide vane throat. The turbine blade 1 can also be a moving blade installed on the rotor, and the turbine blade throat 2 between them is the moving blade throat. The turbine blade throat area is the minimum cross-sectional area of ​​the airflow channel. Figure 1 Shown by dotted 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 performance parameters of the turbine and the target numerical range of the performance parameters. The throat area of ​​the turbine blade determines the flow capacity of the turbine, the pressure between the turbine blade stages, and the temperature between the turbine blade stages. The pressure between the turbine blade stages and the temperature between the turbine blade stages further affect the cooling of the turbine blades, the rim seal between the rotor and stator blades, and the axial force of the rotor. The design of the throat area of ​​the turbine blade needs to achieve the flow capacity of the established turbine and achieve the optimal distribution of the pressure and temperature between the turbine blade stages. The deviation of the throat area of ​​the turbine blade from the design target will deteriorate the pressure and temperature distribution between the turbine blade stages, thereby causing the aerodynamic performance of the turbine to deviate from the design, and will also cause the cooling air flow of the turbine blade to decrease or increase the risk of gas backflow in the rotor and stator rim seal, thereby reducing the aerodynamic efficiency and working reliability of the turbine. Therefore, the determination of the tolerance of the throat area of ​​the multi-stage turbine blade is a multi-objective optimization problem that needs to consider aerodynamic performance, blade cooling, rim seal, and rotor load. Therefore, the performance parameters may include turbine flow, turbine efficiency, pressure between turbine blade stages, and axial force in the flow channel. The turbine blade interstage pressure is the average static pressure between the two-stage turbine blades, for example, the average static pressure between the first-stage guide vanes and the first-stage moving blades, and the average static pressure between the first-stage moving blades and the second-stage guide vanes. The axial force in the flow channel is the axial component of the resultant force of the airflow acting on the moving blades. The turbine can be a two-stage turbine, including first-stage guide vanes, first-stage moving blades, second-stage guide vanes and second-stage moving blades. The target numerical ranges of the performance parameters of the two-stage turbine can be selected as shown in Table 1. The target numerical range of the turbine flow rate is 99% to 101% of its target value, the target numerical range of the turbine efficiency is 99.8% to 100% of its target value, the target numerical range of the interstage pressure of the first-stage guide vanes and the first-stage moving blades is 97% to 103% of its target value, the target numerical range of the interstage pressure of the first-stage moving blades and the second-stage guide vanes is 97% to 103% of its target value, the target numerical range of the interstage pressure of the second-stage guide vanes and the second-stage moving blades is 97% to 103% of its target value, and the target numerical range of the axial force in the flow channel is 95% to 105% of its target value.

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

[0030]

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

[0032] like Figure 2 As shown, the method for determining the tolerance of the throat area of ​​the multi-stage turbine blades also includes step S3. According to the sensitivity results, a mathematical model of the performance parameters changing with the deviation of the throat area of ​​each stage of the turbine blades is obtained. 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] Wherein, Δw is the deviation of turbine flow. Δη is the deviation of turbine efficiency. Δp is the deviation of interstage pressure of a turbine blade. Δfa is the deviation of axial force in the flow channel. i represents the i-th row of turbine blades. For a two-stage turbine, i=1,2,3,4, i=1 represents the first row of turbine blades, i=2 represents the second row of turbine blades, i=3 represents the third row of turbine blades, i=4 represents the fourth row of turbine blades, i=2 represents the second stage moving blades. Δa i is the deviation of the throat area of ​​the i-th row of turbine blades relative to the design value. i is a sensitivity function of the effect of the change in throat area of ​​the i-th row of turbine blades on the turbine flow rate, and the sensitivity function is obtained from the sensitivity result of step S2. is the sensitivity function of the effect of the change in the throat area of ​​the i-th row of turbine blades on the turbine efficiency, and the sensitivity function is obtained from the sensitivity result of step S2. i is the sensitivity function of 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, and the sensitivity function is obtained from the sensitivity result of 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 result of step S2.

[0038] like Figure 2 As shown, the method for determining the tolerance of the throat area of ​​the multi-stage turbine blades also includes step S4. Obtaining the tolerance of the throat area of ​​each stage of the turbine blades. The tolerance of the throat area of ​​each stage of the turbine blades is the allowable deviation range of the throat area of ​​each stage of the turbine blades relative to the design value. The selected tolerance of the throat area of ​​each stage of the turbine blades can be a positive or negative tolerance, 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. According to the mathematical model, a random error analysis is performed to statistically analyze the deviation distribution of the performance parameters when the deviation of the throat area of ​​each stage of the turbine blades is randomly distributed within the tolerance. It can be considered that the random distribution of the deviation of the throat area of ​​each stage of the turbine blades within the tolerance is a normal distribution, the mean μ of the deviation of the throat area of ​​each stage of the turbine blades is zero, and the standard deviation σ of the deviation of the throat area of ​​each stage of the 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 the normal distribution, this makes the deviation of the throat area of ​​each stage of the turbine blades have a probability of 99.73% being within the selected tolerance. The code can be written using MATLAB software or Python software to execute:

[0040] The throat area of ​​each stage of turbine blades is normally distributed, and the deviation Δa of the throat area of ​​each stage of turbine blades is obtained randomly for the nth time. 1n , Δa 2n ,…,Δa in , where Δa i The meaning of is as mentioned above, n represents the random data of the nth time, that is, the number of cycles n, the maximum value of n can be m, n = 1, 2, 3, ... m, the deviation Δa of the throat area of ​​each stage of turbine blades 1n , Δa 2n ,…,Δa in Substitute into the mathematical model of step S3 and calculate the deviation Δw of each performance parameter n , Δη n , Δp n , Δfa n , the relevant meaning is as mentioned above, the cycle is as follows:

[0041] The number of cycles n = 1, the deviation Δa of the throat area of ​​each stage of turbine blades is randomly obtained for the first time 11 , Δa 21 ,…,Δa i1 , substitute into the mathematical model of step S3, and calculate the deviations of each performance parameter Δw1, Δη1, Δp1, Δfa1;

[0042] The number of cycles n = 2, the deviation Δa of the throat area of ​​each stage of turbine blades is randomly obtained for the second time 12 , Δa 22 ,…,Δa i2 , substitute into the mathematical model of step S3, and calculate the deviations of each performance parameter Δw2, Δη2, Δp2, Δfa2;

[0043] …

[0044] The number of cycles η = m, the deviation Δa of the throat area of ​​each stage of turbine blades is obtained randomly for the mth time 1m , Δa 2m ,…,Δa im , substitute into the mathematical model of step S3, and calculate the deviation Δw of each performance parameter m , Δη m , Δp m , Δfa m ;

[0045] At the end, the deviations of the m groups of performance parameters are obtained, and the deviation distribution of the performance parameters is obtained when the deviations of the throat areas of turbine blades at each stage are randomly distributed within the tolerance.

[0046] like Figure 2 As shown, the method for determining the tolerance of the throat area of ​​a multi-stage turbine blade also includes step S6. Determine whether the deviation distribution is within the target numerical range. If so, output the tolerance. If not, execute step S4. The standard deviation of the deviation distribution of the performance parameter can be obtained, and it is determined whether the positive and negative three times the standard deviation are within the target numerical range to determine whether the deviation distribution is within the target numerical range. Taking the deviation of the turbine flow rate as an example, the deviations Δw1, Δw2, ..., Δw of the m groups of turbine flows obtained in step S5 are calculated. m The standard deviation S of ±3S is compared with the target numerical range of the turbine flow in step S1. If ±3S is included in the target numerical range of the turbine flow, the deviation distribution of the turbine flow is within its target numerical range. If ±3S is not included in the target numerical range of the turbine flow, the deviation distribution of the turbine flow is not within its target numerical range. The above method is used to traverse all the performance parameters to determine whether the deviation distribution of each performance parameter is within the target numerical range of the performance parameter. If the deviation distribution of each performance parameter is within the target numerical range of the performance parameter, the tolerance of step S4 can meet the requirements of each performance parameter, and the tolerance of step S4 is output and the end. If part or all of the deviation distribution of each performance parameter is not within the target numerical range of the performance parameter, the tolerance of step S4 does not meet the requirements of each performance parameter, and step S4 is executed again to obtain a new tolerance, and steps S5 and S6 are executed according to the new tolerance. The new tolerance obtained by executing step S4 again can be smaller than the tolerance obtained by executing step S4 the previous time, so that the deviation distribution in step S6 is more likely to be within the target numerical range.

[0047] The method for determining the tolerance of the throat area of ​​a multi-stage turbine blade is used to determine the tolerance of the throat area of ​​each stage of the turbine blade in the multi-stage turbine. The tolerance requirements are implemented in the drawing requirements of turbine blade castings and parts, and the turbine blade throat area is controlled from the source of design and manufacturing, which is convenient for controlling the deviation of the turbine blade throat area from the design value, reducing the adverse effects of the turbine blade throat area deviating from the design value on the performance and reliability of the turbine engine, and reducing the unevenness of the throat area of ​​the entire turbine blade.

[0048] A computer device includes a processor and a memory, wherein 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-mentioned method for determining the throat area tolerance of multi-stage turbine blades.

[0049] A computer-readable storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded by a processor to execute the steps in the above-mentioned method for determining the throat area tolerance of a multi-stage turbine blade.

[0050] The steps of the method or algorithm 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 the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0051] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

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

Claims

1. A method for determining the tolerance of throat area of ​​multi-stage turbine blades, characterized in that include: Step S1. Obtaining the performance parameters of the turbine and the target numerical range of the performance parameters; Step S2. Obtaining the sensitivity results of the performance parameters as the throat areas of turbine blades at various levels change; Step S3. According to the sensitivity results, a mathematical model of the performance parameter changing with the deviation of the throat area of ​​each stage of turbine blades is obtained; Step S4. Obtaining the tolerance of throat area of ​​turbine blades at each level; Step S5. Perform random error analysis according to the mathematical model, and calculate the deviation distribution of the performance parameter when the deviation of the throat area of ​​each level of turbine blades is randomly distributed within the tolerance; and Step S6: Determine whether the deviation distribution is within the target value range. If so, output the tolerance. If not, execute step S4.

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

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

4. The method for determining the throat area tolerance of a multi-stage turbine blade according to claim 1, characterized in that: In step S4, the tolerance is a positive and 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 a multi-stage turbine blade according to claim 4, characterized in that: In step S5, 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 of the deviation of the throat area of ​​each stage of turbine blades is zero, and the standard deviation of the deviation of the throat area of ​​each stage of turbine blades is one third of the upper deviation of the tolerance.

6. The method for determining the throat area tolerance of a multi-stage turbine blade according to claim 1, characterized in that: The step S6 includes obtaining the standard deviation of the deviation distribution of the performance parameter, and determining whether positive and negative three times the standard deviation are within the target numerical range, so as to determine whether the deviation distribution is within the target numerical range.

7. A computer device, characterized in that: 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 method for determining the throat area tolerance of a multi-stage turbine blade as described in 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, and the instructions are suitable for being loaded by a processor to execute 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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