End wall grooving method, device and equipment for cascade test

Abstract

The embodiment of the invention provides an end wall grooving method, device and equipment for a cascade test, and the method comprises the steps: obtaining geometric parameters of a cascade according to the size of a test bench and a target two-dimensional blade profile of a plane cascade test; performing three-dimensional flow simulation calculation on the cascade by utilizing computational fluid mechanics based on the geometric parameters of the cascade; post-processing the simulation calculation result to obtain a surface streamline of the blade grid; according to the surface streamline of the blade grid, obtaining separation data of blade grid corner separation; determining slot parameters of the cascade according to at least one of the geometric parameters, the separation data and the slot parameters of the cascade; and based on the geometric parameters and the groove parameters of the blade grid, blade grid machining and end wall grooving are carried out. According to the embodiment of the invention, AVDR in a plane cascade test can be effectively reduced, and a test result can better reflect the performance of a two-dimensional blade profile.

Description

Technical Field

[0001] The embodiments of this specification relate to the field of turbomachinery aerodynamics, and in particular, to an end wall slotting method, device and equipment for blade cascade testing. Background Art

[0002] Plane cascade test is an important method for evaluating compressor blade performance. A large number of plane cascade tests have been applied to the study of various classic two-dimensional blades. Due to the limited span size of the test blade, endwall boundary layer separation will occur at the endwalls at both ends of the blade, blocking the endwall flow and squeezing the middle blade height flow channel. As the cascade axial density ratio (AVDR) increases and the three-dimensional effect is enhanced, the flow at the middle blade height will deviate from the two-dimensional flow, resulting in inaccurate evaluation of the two-dimensional blade performance. Especially under large positive angle of attack conditions, this phenomenon may lead to an underestimation of blade losses, making the estimation of the stable operating range of the blade too optimistic, bringing difficulties and hidden dangers to blade design. In order to make the test results more accurately and reliably reflect the performance of the two-dimensional blade, it is necessary to control the endwall separation and reduce the AVDR.

[0003] In the prior art, the boundary layer suction method requires additional equipment and energy. These suction devices are complex and expensive, which greatly increases the test cost and operation difficulty. On the other hand, for different plane blades and different operating conditions of the same blade, the size and position of the end wall separation are different, and the required suction position and suction volume are also different. At present, there is a lack of corresponding guidance for the selection of suction position and suction volume, and it is difficult to control the appropriate suction flow in actual operation.

[0004] The blade scaling method changes the geometric dimensions of the blade, that is, changes the Reynolds number of the blade. The performance of the scaled blade has changed compared to the prototype. If the Reynolds number after scaling is lower than the critical Reynolds number, changes in flow phenomena such as separation will occur, causing significant changes in the blade flow and performance. The test results are bound to deviate from the true performance of the two-dimensional blade. On the other hand, in order to make the AVDR small enough, the aspect ratio often needs to be 4 or even higher, and the chord length of the blade will be much smaller. The blades will show a "slender" characteristic, resulting in insufficient strength and inability to conduct tests. Moreover, for the existing blade test wind tunnels, their dimensions are fixed and cannot support scaling with an aspect ratio of 4 or even higher.

[0005] The purpose of existing research on slotting is to reduce separation, reduce total pressure loss, and improve blade performance. However, the plane blade test needs to obtain two-dimensional blade performance. The purpose of slotting to control separation is to reduce the influence of end zone separation on the flow at the middle blade height, so that the flow at the middle blade height can be restored to two-dimensionality. The purposes of the two are different, and the corresponding slotting criteria and methods are also different. Therefore, the current slot design method cannot achieve the purpose of the plane blade test.

[0006] For full blade height slotting, it actually changes the two-dimensional blade geometry, and the slotted blade performance obtained in the test is no longer the performance of the original blade geometry. For end zone slotting, although it has the effect of reducing angular separation, there is no attention and control on whether the flow at the middle blade height can restore the two-dimensional flow. The design that can reduce the loss cannot effectively reduce AVDR in the full attack angle range, so that the flow at the middle blade height can restore the two-dimensionality. On the other hand, the slot jet itself will bring mixing losses and increase the total pressure loss of the blade grid. Therefore, the current end zone slot design for the purpose of reducing losses needs to make the following two trade-offs: 1. Reduced losses caused by weakened angular separation; 2. Increased losses caused by jet mixing. Therefore, complex slots such as "S" slots appear. For plane blade grid tests, this increases the difficulty of slot design and processing, and is unnecessary.

[0007] Therefore, there is an urgent need for an end wall slotting method for cascade tests that can effectively reduce the AVDR in plane cascade tests and enable the test results to better reflect the performance of the two-dimensional blade profile. Summary of the invention

[0008] The purpose of the embodiments of this specification is to provide an end wall slotting method, device and equipment for blade cascade testing, so as to effectively reduce the AVDR in the plane blade cascade test, so that the test results can better reflect the performance of the two-dimensional blade.

[0009] To achieve the above objectives, on the one hand, an embodiment of the present specification provides an end wall slotting method for a cascade test, comprising:

[0010] According to the size of the test bench and the target two-dimensional blade shape of the plane cascade test, the geometric parameters of the cascade are obtained;

[0011] Based on the geometric parameters of the blade cascade, a three-dimensional flow simulation calculation is performed on the blade cascade using computational fluid dynamics;

[0012] Post-process the simulation results to obtain the surface streamlines of the cascade;

[0013] According to the surface streamlines of the cascade, separation data of the cascade angle zone separation is obtained;

[0014] determining slot parameters of the cascade based on at least one of geometric parameters of the cascade, separation data, and slot parameters;

[0015] Based on the geometric parameters and slot parameters of the blade row, blade row processing and end wall slotting are performed.

[0016] Preferably, the geometric parameters of the blade cascade include: blade height, blade profile line scatter coordinates, chord length, consistency, aspect ratio, inlet geometric angle and installation angle.

[0017] Preferably, the separation data of the blade cascade angle zone separation includes: a separation zone, a separation starting position, a separation center and a separation span range.

[0018] Preferably, the slot parameters of the blade grid include: slot outlet position, slot height, slot width and slot direction angle.

[0019] Preferably, the slot parameters of the blade grid include: slot centerline position, slot width, slot start position, and slot end position.

[0020] Preferably, the slot parameters of the blade grid include: vertical slot parameters and transverse slot parameters, wherein the vertical slot parameters include slot outlet position, slot height, slot width and slot direction angle, and the transverse slot parameters include slot centerline position, slot width, slot start position and slot end position.

[0021] Preferably, determining the slot parameters of the cascade according to at least one of the geometric parameters, separation data and slot parameters of the cascade further comprises:

[0022] According to the separation data of the blade cascade, the slot outlet position is set to be located at the separation center;

[0023] According to the geometric parameters of the blade cascade, the groove height is set to 10% of the blade height;

[0024] According to the geometric parameters of the blade cascade, the slot width is set to 1% chord length to 2% chord length;

[0025] The slot inlet is arranged to be located on the pressure surface of the cascade according to the geometric parameters of the cascade, and the distance from the slot inlet to the leading edge of the cascade is greater than 50% of the chord length;

[0026] According to the separation data of the blade cascade, the slot outlet is set to be located at the suction surface of the blade cascade, and the slot outlet position is located at the separation center;

[0027] According to the positions of the slot inlet and the slot outlet, several alternative direction angles are obtained;

[0028] The smallest of the several candidate direction angles is used as the groove direction angle.

[0029] Preferably, determining the slot parameters of the cascade according to at least one of the geometric parameters, separation data and slot parameters of the cascade further comprises:

[0030] According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall;

[0031] According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height;

[0032] According to the geometric parameters of the blade cascade, the starting position of the groove is set to be at 60% of the chord length from the leading edge;

[0033] According to the geometric parameters of the blade cascade, the end of the slot is set to be located at 90% of the chord length from the leading edge.

[0034] Preferably, determining the slot parameters of the cascade according to at least one of the geometric parameters, separation data and slot parameters of the cascade further comprises:

[0035] According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall;

[0036] According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height;

[0037] Setting the slot outlet position of the blade cascade to the slot start position;

[0038] According to the geometric parameters of the blade cascade, the end of the slot is set to be located at 90% of the chord length from the leading edge.

[0039] On the other hand, an embodiment of the present specification provides an end wall slotting device for a cascade test, the device comprising:

[0040] A parameter determination module, for obtaining geometric parameters of the cascade according to the size of the test bench and the target two-dimensional blade profile of the plane cascade test;

[0041] A simulation calculation module, used for performing three-dimensional flow simulation calculation on the blade cascade by using computational fluid dynamics based on the geometric parameters of the blade cascade;

[0042] A result processing module is used to post-process the simulation calculation results to obtain the surface streamlines of the cascade;

[0043] A separation data determination module, used for obtaining separation data of the cascade angle zone separation according to the surface streamline of the cascade;

[0044] a slot parameter determination module, for determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data and the slot parameters;

[0045] The processing and grooving module is used to perform blade processing and end wall grooving based on the geometric parameters and groove parameters of the blade.

[0046] On the other hand, an embodiment of the present specification further provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein when the computer program is executed by the processor, the instructions of any one of the above methods are executed.

[0047] It can be seen from the technical solutions provided in the above embodiments of this specification that, through the method of the embodiments of this specification, the geometric parameters of the blade are first determined, and then a three-dimensional flow simulation calculation is performed. The surface streamlines of the blade are obtained by post-processing the simulation calculation results, and the separation data of the blade is further obtained. Based on at least one of the geometric parameters, the separation data and the slot parameters, the slot parameters of the blade are obtained, and finally the blade is processed and slotted. After subsequent plane blade tests, it is found that the slotting of the blade end wall reduces the AVDR, and the flow in the blade is restored to a two-dimensional flow, so as to better predict the performance of the two-dimensional blade shape.

[0048] In order to make the above and other purposes, features and advantages of the present specification more obvious and easy to understand, the following specifically cites preferred embodiments and describes them in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 A schematic flow chart of an end wall slotting method for a cascade test provided in an embodiment of this specification is shown;

[0051] Figure 2A A schematic diagram of the structure of a first blade cascade provided in an embodiment of this specification is shown;

[0052] Figure 2B A schematic diagram of the structure of a second blade cascade provided in an embodiment of this specification is shown;

[0053] Figure 2C A schematic diagram of the structure of a third type of cascade provided in an embodiment of this specification is shown;

[0054] Figure 3 The surface streamline diagram of the cascade provided by the embodiment of this specification is shown;

[0055] Figure 4A A top view of a cascade provided in a specific embodiment of the present specification is shown;

[0056] Figure 4B A front view of a cascade provided in a specific embodiment of the present specification is shown;

[0057] Figure 5 A comparison diagram of total pressure loss between CFD calculation and test provided in a specific embodiment of this specification is shown;

[0058] Figure 6A comparison diagram of cascade surface streamlines obtained by CFD calculation and testing provided in a specific embodiment of this specification is shown;

[0059] Fig. 7A A comparison diagram of the total pressure loss of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in a specific embodiment of this specification is shown;

[0060] Figure 7B A comparison diagram of the trailing angles of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in a specific embodiment of this specification is shown;

[0061] Figure 7C The AVDR comparison diagram of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in a specific embodiment of the present specification is shown;

[0062] Figure 8 The streamline diagram and Mach number cloud diagram at a typical angle of attack provided by a specific embodiment of this specification are shown;

[0063] Fig. 9A A top view of a cascade provided in another specific embodiment of the present specification is shown;

[0064] Fig. 9B A front view of a cascade provided in another specific embodiment of the present specification is shown;

[0065] Fig. 10A A comparison diagram of the total pressure loss of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in another specific embodiment of the present specification is shown;

[0066] Fig. 10B A comparison diagram of the trailing angles of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in another specific embodiment of the present specification is shown;

[0067] Fig. 10C A comparison diagram of AVDR of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in another specific embodiment of the present specification is shown;

[0068] Fig.11A A top view of a cascade provided in another specific embodiment of the present specification is shown;

[0069] Fig. 11B A front view of a cascade provided in another specific embodiment of the present specification is shown;

[0070] Fig. 12AA comparison diagram of the total pressure loss of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in another specific embodiment of the present specification is shown;

[0071] Fig. 12B A comparison diagram of the trailing angles of a two-dimensional blade profile, a three-dimensional prototype blade cascade with no slots at 50% of the blade height, and a three-dimensional slotted blade cascade at 50% of the blade height provided by another specific embodiment of the present specification is shown;

[0072] Fig. 12C A comparison diagram of AVDR of a two-dimensional blade profile, a 50% blade height section of a three-dimensional prototype blade cascade without slots, and a 50% blade height section of a three-dimensional slotted blade cascade provided in another specific embodiment of the present specification is shown;

[0073] Fig.13 A schematic diagram of the module structure of an end wall slotting device for a cascade test provided in an embodiment of this specification is shown;

[0074] Fig.14 A schematic diagram of the structure of a computer device provided in an embodiment of this specification is shown.

[0075] Description of the accompanying symbols:

[0076] 100. Parameter determination module;

[0077] 200. simulation calculation module;

[0078] 300, result processing module;

[0079] 400, separation data determination module;

[0080] 500, slot parameter determination module;

[0081] 600, processing slotting module;

[0082] 1002. Computer equipment;

[0083] 1004. Processor;

[0084] 1006. Memory;

[0085] 1008. Driving mechanism;

[0086] 1010, input / output module;

[0087] 1012. Input device;

[0088] 1014. Output device;

[0089] 1016. Presentation equipment;

[0090] 1018. Graphical user interface;

[0091] 1020. Network interface;

[0092] 1022. Communication link;

[0093] 1024. Communication bus. DETAILED DESCRIPTION

[0094] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of this specification.

[0095] The purpose of existing research on slotting is to reduce separation, reduce total pressure loss, and improve blade performance. However, the plane blade test needs to obtain two-dimensional blade performance. The purpose of slotting to control separation is to reduce the influence of end zone separation on the flow at the middle blade height, so that the flow at the middle blade height can be restored to two-dimensionality. The purposes of the two are different, and the corresponding slotting criteria and methods are also different. Therefore, the current slot design method cannot achieve the purpose of the plane blade test.

[0096] For full blade height slotting, it actually changes the two-dimensional blade geometry, and the slotted blade performance obtained in the test is no longer the performance of the original blade geometry. For end zone slotting, although it has the effect of reducing angular separation, there is no attention and control on whether the flow at the middle blade height can restore the two-dimensional flow. The design that can reduce the loss cannot effectively reduce AVDR in the full attack angle range, so that the flow at the middle blade height can restore the two-dimensionality. On the other hand, the slot jet itself will bring mixing losses and increase the total pressure loss of the blade grid. Therefore, the current end zone slot design for the purpose of reducing losses needs to make the following two trade-offs: 1. Reduced losses caused by weakened angular separation; 2. Increased losses caused by jet mixing. Therefore, complex slots such as "S" slots appear. For plane blade grid tests, this increases the difficulty of slot design and processing, and is unnecessary.

[0097] In order to solve the above problems, an embodiment of the present specification provides an end wall slotting method for a cascade test. Figure 1 This is a flow chart of a method for grooving an end wall of a blade cascade test provided in an embodiment of this specification. This specification provides method operation steps as described in the embodiment or flow chart, but more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiment is only one way of executing the order of many steps and does not represent the only execution order. When the actual system or device product is executed, it can be executed in the order of the method shown in the embodiment or the figure or in parallel.

[0098] It should be noted that the terms "first", "second", etc. in the description and claims of the embodiments of this specification and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of this specification described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0099] Reference Figure 1 The embodiment of this specification provides an end wall slotting method for a cascade test, comprising:

[0100] S101: obtaining geometric parameters of the cascade according to the size of the test bench and the target two-dimensional blade profile of the plane cascade test;

[0101] S102: Based on the geometric parameters of the blade cascade, using computational fluid dynamics to perform three-dimensional flow simulation calculation on the blade cascade;

[0102] S103: Post-processing the simulation calculation results to obtain the surface streamlines of the cascade;

[0103] S104: obtaining separation data of cascade angle zone separation according to surface streamlines of the cascade;

[0104] S105: determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data and the slot parameters;

[0105] S106: Based on the geometric parameters and slot parameters of the blade row, blade row processing and end wall slotting are performed.

[0106] Among them, refer to Figure 2A-2C The embodiments of this specification provide three different slotting schemes, and thus the structural schematic diagrams of three different blade grids can be obtained. The size of the test bench can determine the blade height of the blade grid. The target two-dimensional blade profile of the plane blade grid test defines the blade profile line scatter coordinates, chord length, consistency, aspect ratio, inlet geometric angle and installation angle of the blade grid, and the size of the test bench defines the blade height of the blade grid. The geometric parameters of the blade grid obtained include: blade height, blade profile line scatter coordinates, chord length, consistency, aspect ratio, inlet geometric angle and installation angle, wherein the blade profile line scatter coordinates are composed of scatter coordinates, which characterize the geometric appearance of the blade grid.

[0107] Based on the geometric parameters of the blade, computational fluid dynamics (CFD) can be used to simulate the actual fluid flow conditions for calculation. Before CFD simulation calculation, the end wall boundary condition of the blade needs to be set to a no-slip wall. The simulation calculation result of CFD is the flow field parameter of the blade. Post-processing the flow field parameters of the blade can obtain the surface streamlines of the blade, and then obtain the separation data of the blade angle separation.

[0108] Specifically, refer to Figure 3 The separation data of the blade angle zone separation includes: separation zone, separation starting position, separation center and separation span range.

[0109] According to at least one of the geometric parameters, separation data and slot parameters of the blade grid, the slot parameters of the blade grid can be determined. The slot parameters are the parameters of the slot when the end wall of the blade grid is slotted. In the embodiments of this specification, three slotting schemes are specifically: the first scheme is to only open vertical slots, the second scheme is to only open horizontal slots, and the third scheme is to open vertical slots and horizontal slots at the same time.

[0110] In the slotting scheme, the selection of slot parameters (mainly the selection of slot width) has a great influence on the slotting effect. For the first scheme (vertical slot), when the slot width is too small, the slot jet intensity may not be sufficient to suppress separation. When the slot width is too large, the slot jet may bring too strong a lateral momentum component, hindering the mainstream flow downstream. For the second scheme (transverse slot), inappropriate slot width may cause the slot to be blocked, and it is difficult for the fluid to form a jet through the slot. Therefore, the above two schemes are combined to add a transverse slot downstream of the vertical slot to form a third scheme. In the third scheme, the selection of slot parameters has a relatively small effect on the slotting effect, and the slot parameters can be selected within a larger range to achieve the same effect of controlling AVDR.

[0111] The slot parameters of the blade corresponding to the first scheme include: slot outlet position, slot height, slot width and slot direction angle. The blade is processed and the end wall is slotted based on the geometric parameters and slot parameters of the blade.

[0112] The slot parameters of the blade grid corresponding to the second solution include: slot centerline position, slot width, slot start position, and slot end position.

[0113] The slot parameters of the blade grid corresponding to the third scheme include: vertical slot parameters and transverse slot parameters, wherein the vertical slot parameters include slot outlet position, slot height, slot width and slot direction angle, and the transverse slot parameters include slot centerline position, slot width, slot start position and slot end position.

[0114] In the first and third solutions of the embodiments of the present specification, since there are slot outlet positions, slot heights, slot widths and slot direction angles, for the first and third solutions, determining the slot parameters of the cascade according to at least one of the geometric parameters, separation data and slot parameters of the cascade further includes:

[0115] According to the separation data of the blade cascade, the slot outlet position is set to be located at the separation center;

[0116] According to the geometric parameters of the blade cascade, the groove height is set to 10% of the blade height;

[0117] According to the geometric parameters of the blade cascade, the slot width is set to 1% chord length to 2% chord length;

[0118] The slot inlet is arranged to be located on the pressure surface of the cascade according to the geometric parameters of the cascade, and the distance from the slot inlet to the leading edge of the cascade is greater than 50% of the chord length;

[0119] According to the separation data of the blade cascade, the slot outlet is set to be located at the suction surface of the blade cascade, and the slot outlet position is located at the separation center;

[0120] According to the positions of the slot inlet and the slot outlet, several alternative direction angles are obtained;

[0121] The smallest of the several alternative direction angles is used as the slot direction angle. Specifically, after the positions of the slot inlet and the slot outlet have been determined, the slot direction angle can be determined, but because the distance from the slot inlet to the leading edge of the blade is greater than 50% of the chord length, only several approximate positions of the slot inlet can be determined, thereby obtaining several alternative direction angles, and the smallest of the several alternative direction angles is the slot direction angle.

[0122] In a second solution of the embodiment of the present specification, determining the slot parameters of the cascade according to at least one of the geometric parameters, separation data and slot parameters of the cascade further comprises:

[0123] According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall;

[0124] According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height;

[0125] According to the geometric parameters of the blade cascade, the starting position of the groove is set to be at 60% of the chord length from the leading edge;

[0126] According to the geometric parameters of the blade cascade, the end of the slot is set to be located at 90% of the chord length from the leading edge.

[0127] In the third solution of the embodiment of the present specification, in addition to the aforementioned vertical slot parameters slot outlet position, slot height, slot width and slot direction angle, transverse slot parameters are also included. Therefore, for the third solution, the slot parameters of the cascade are determined based on at least one of the geometric parameters, separation data and slot parameters of the cascade, and further include:

[0128] According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall;

[0129] According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height;

[0130] Setting the slot outlet position of the blade cascade to the slot start position;

[0131] According to the geometric parameters of the blade cascade, the end position of the slot is set to be located at 90% of the chord length from the leading edge. After the blade cascade is processed and the end wall is slotted, a plane blade cascade test can be carried out.

[0132] The following is an explanation through a specific embodiment. Taking a certain axial compressor blade profile as the research object, combined with the test bench size and the target two-dimensional blade profile of the plane blade cascade test, the plane two-dimensional parameters of the blade cascade geometric parameters are formed as shown in Table 1.

[0133] Table 1

[0134]

[0135]

[0136] Table 1 does not reflect the scatter point coordinates of the blade profile line. The reason is that the scatter point coordinates of the blade profile line are scatter point coordinates and cannot be represented by the value of the parameter. Further, based on the geometric parameters of the blade cascade, a single-pass steady-state RANS calculation is performed on the blade cascade. This is a method used to simulate fluid flow in computational fluid dynamics (CFD). Since the geometry and flow of the blade cascade are symmetrical about the 50% blade height section, the flow at 0-50% blade height is symmetrical to the flow at 50-100% blade height. Therefore, this embodiment only performs CFD calculations on half of the blade cascade channel (i.e., 0-50% blade height) in the span direction, and the 50% blade height section is set as the symmetry plane. The 50-100% blade height and the 0-50% blade height are completely symmetrical about the 50% blade height section, and the 50-100% blade height will not be repeated.

[0137] Thus, the separation data are obtained: separation area, separation starting position, separation center and separation span range, where the separation center is at about 80% of the chord length.

[0138] Reference Figure 4A and Figure 4B For the first solution, the slot parameters are selected based on the geometric parameters of the cascade and the separation data:

[0139] a) Slot exit position: At the separation center, selected as the 80% chord length position.

[0140] b) Groove height: The groove starts from the end wall and its height is about 10% of the leaf height.

[0141] c) Slot width: The slot width is selected to be 1.1% of the chord length.

[0142] d) Slot direction angle: selected as 48.8°.

[0143] After machining and slotting the cascade, the plane cascade test was carried out.

[0144] The above process is the specific implementation part of the method in this specification. The effect after the specific implementation of the method is further verified through the following process. The CFD calculation method is used to calculate and compare the flow and performance of the two-dimensional blade shape, the unslotted three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section. The results show that the flow and performance of the three-dimensional slotted blade cascade 50% blade height section are closer to the two-dimensional blade shape.

[0145] The specific verification process is as follows:

[0146] like Figure 5 As shown in the figure, it is a comparison chart of the total pressure loss between CFD calculation and test. Figure 6 As shown, it is a comparison of the streamlines on the blade surface calculated by CFD and tested. Figure 6 The two figures on the left are the streamline diagrams of the experimental blade surface, and the two figures on the right are the streamline diagrams of the blade surface calculated by CFD. The upper left and upper right figures can be compared when i=-3°, and the lower left and lower right figures can be compared when i=10°.

[0147] It should be noted that the purpose of comparing the total pressure loss and blade surface streamlines calculated by CFD and tested in this specification is to verify the reliability of the CFD calculation results, and this process is generally required to be included in CFD-based research. Figure 5 and Figure 6 The experimental results are consistent with the CFD calculation results, indicating that the CFD calculation results are reliable, which proves the effectiveness of the discussion and analysis based on the CFD results below.

[0148] In order to better measure the effect of the slotting of the blade end wall on the AVDR, a certain comparison can be made. Specifically, CFD calculations are performed on a 50% blade height section of a three-dimensional prototype blade without slots, a 50% blade height section of a three-dimensional slotted blade slotted according to the method in the embodiment of this specification, and a two-dimensional blade profile to obtain the total pressure loss, trailing angle characteristics, AVDR and flow characteristics of the two at different attack angles.

[0149] Fig. 7A and Figure 7B The total pressure loss and trailing angle characteristics of a two-dimensional blade profile, a three-dimensional prototype blade cascade with no slots and a three-dimensional slotted blade cascade with a 50% blade height section are shown. The performance of the three-dimensional prototype blade cascade deviates greatly from that of the two-dimensional blade profile under positive and negative angles of attack. When i = -3° (large negative angle of attack), the total pressure loss deviation is about 26.39%, and when i = +9° (large positive angle of attack), the total pressure loss deviation is about 22.27%. At different angles of attack, the trailing angle deviation between the three-dimensional prototype blade cascade and the two-dimensional blade profile is between 1.5° and 2°. This indicates that due to the influence of angular zone separation, the three-dimensional prototype blade cascade cannot well predict the performance of the two-dimensional blade profile.

[0150] The three-dimensional slotted blade cascade better predicts the performance of the two-dimensional blade profile. When i = -3° (large negative angle of attack), the total pressure loss deviation is about 7.28%, and when i = +9° (large positive angle of attack), the total pressure loss deviation is about 1.54%. At different angles of attack, the deviation of the trailing angle between the three-dimensional slotted blade cascade and the two-dimensional blade profile is less than 0.5°.

[0151] Reference Figure 7C , showing the change of axial velocity density ratio AVDR (Axial Velocity Density Ratio) at different angles of attack. The larger the AVDR, the stronger the three-dimensional effect of the flow, and the greater the deviation of the performance of the 50% blade height section from the two-dimensional blade shape. The AVDR of the two-dimensional blade shape is 1. It can be seen that the AVDR of the three-dimensional prototype blade is higher than 1.1, and increases with the increase of the angle of attack. The AVDR of the three-dimensional slotted blade is reduced. Except for large negative angles of attack, the AVDR drops to about 1.05.

[0152] Figure 8 According to the flow characteristics of the two-dimensional blade profile, the three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section at typical attack angles, the corresponding streamline diagrams and Mach number cloud diagrams at typical attack angles are obtained. Figure 8 (a)-(c) are the streamline diagrams and Mach number cloud diagrams of the two-dimensional blade profile, the three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section at +9° attack angle, respectively. Figure 8(d)-(f) are the streamline diagrams and Mach number cloud diagrams of the two-dimensional blade profile, the three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section at +1° attack angle, respectively. Figure 8 (g)-(i) are the streamline diagrams and Mach number cloud diagrams of the two-dimensional blade profile, the three-dimensional prototype blade section at 50% blade height, and the three-dimensional slotted blade section at 50% blade height at an attack angle of -3°.

[0153] The results show that the flow of fluid in the 50% blade height section of the three-dimensional slotted cascade is closer to the flow of the two-dimensional blade. When i = +9°, due to the larger normal incidence angle, the two-dimensional blade flow produces a larger trailing edge separation on the suction surface. In the three-dimensional prototype cascade, the trailing edge separation is significantly reduced. This is because the AVDR of the three-dimensional prototype cascade is very large, which compresses the flow channel of 50% blade height, accelerates the flow, and suppresses the trailing edge separation on the suction surface. After the cascade is slotted, the AVDR decreases, the flow acceleration in the cascade is weakened, and the suction surface trailing edge separation returns to the two-dimensional blade flow state. The increase in separation leads to an increase in total pressure loss and backward angle, which returns to the level of the two-dimensional blade. When i = +1°, the changes caused by slotting are similar to those when i = +9°. However, since the trailing edge separation of the suction surface of the two-dimensional blade flow is smaller when i = +1°, the changes between the three are very small, and the overall performance remains basically unchanged. When i = -3°, compression waves appear in the two-dimensional blade channel, and the flow acceleration caused by AVDR leads to increased compression waves and increased losses. After grooving, AVDR decreases, compression wave intensity decreases, and losses decrease.

[0154] Reference Fig. 9A and Fig. 9B For the second solution, the slot parameters are selected in combination with the geometric parameters of the cascade:

[0155] a) Groove centerline position: Select a position 5% of the blade height from the end wall.

[0156] b) Groove width: about 2% of leaf height.

[0157] c) Groove start position: Select a point that is 60% of the chord length from the leading edge.

[0158] d) Slot end position: Select the point where the distance from the leading edge is 90% of the chord length.

[0159] After machining and slotting the cascade, the plane cascade test was carried out.

[0160] Fig. 10A and Fig. 10B The total pressure loss and trailing angle characteristics of the two-dimensional blade profile, the unslotted three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section are shown. When i = +9° (large positive angle of attack), the total pressure loss deviation is about 0.99%. At different angles of attack, the trailing angle deviation between the three-dimensional slotted blade cascade and the two-dimensional blade profile is less than 0.3°.

[0161] Reference Fig. 10C , showing the change of axial velocity density ratio AVDR (Axial Velocity Density Ratio) at different angles of attack. The larger the AVDR, the stronger the three-dimensional effect of the flow, and the greater the deviation between the performance of the 50% blade height section and the two-dimensional blade profile. The AVDR has decreased to about 1.05.

[0162] Reference Fig.11A and Fig. 11B For the third solution, the slot parameters are selected by combining the geometric parameters of the cascade and the slot parameters:

[0163] a) Slot exit position: At the separation center, selected as the 80% chord length position.

[0164] b) Groove height: The groove starts from the end wall and its height is about 10% of the leaf height.

[0165] c) Slot width: The slot width is selected to be 1.1% of the chord length.

[0166] d) Slot direction angle: selected as 48.8°.

[0167] e) Groove centerline position: Select a position 5% of the leaf height from the end wall.

[0168] f) Groove width: about 2% of leaf height.

[0169] g) Groove start position: Select the groove exit position as the groove start position.

[0170] h) Slot end position: Select the position where the distance from the leading edge is 90% of the chord length.

[0171] After machining and slotting the cascade, the plane cascade test was carried out.

[0172] Fig. 12A and Fig. 12B The total pressure loss and trailing angle characteristics of the two-dimensional blade profile, the unslotted three-dimensional prototype blade cascade 50% blade height section, and the three-dimensional slotted blade cascade 50% blade height section are shown. When i = +9° (large positive angle of attack), the total pressure loss deviation is about 4.54%. At different angles of attack, the trailing angle deviation between the three-dimensional slotted blade cascade and the two-dimensional blade profile is less than 0.5°.

[0173] Reference Fig. 12C , showing the change of axial velocity density ratio AVDR (Axial Velocity Density Ratio) at different angles of attack. The larger the AVDR, the stronger the three-dimensional effect of the flow, and the greater the deviation between the performance of the 50% blade height section and the two-dimensional blade profile. The AVDR has decreased to about 1.05.

[0174] In summary, through the method of the embodiment of this specification, the geometric parameters of the blade are first determined, and then a three-dimensional flow simulation calculation is performed. The surface streamlines of the blade are obtained by post-processing the simulation calculation results, and the separation data of the blade is further obtained. Based on at least one of the geometric parameters, separation data and slot parameters, the slot parameters of the blade are obtained, and finally the blade is processed and slotted. After subsequent plane blade tests, it is found that the slotting of the blade end wall reduces the AVDR, and the flow in the blade is restored to a two-dimensional flow, which better predicts the performance of the two-dimensional blade shape.

[0175] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with the relevant laws, regulations and standards of the relevant countries and regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0176] This application provides users with corresponding big data analysis (such as personal biometrics, identity data, consumption data, asset data, electronic terminal operation data, etc.) operation entrances for users to choose to agree or reject automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered.

[0177] Based on the above-mentioned end wall slotting method for blade grid test, the embodiment of this specification also provides an end wall slotting device for blade grid test. The device may include a system (including a distributed system), software (application), module, component, server, client, etc. using the method described in the embodiment of this specification and a device combined with necessary implementation hardware. Based on the same innovative concept, the device in one or more embodiments provided in the embodiment of this specification is as described in the following embodiments. Since the implementation scheme and method of the device to solve the problem are similar, the implementation of the specific device in the embodiment of this specification can refer to the implementation of the aforementioned method, and the repetitions will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements predetermined functions. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0178] Specifically, Fig.13 This is a schematic diagram of the module structure of an embodiment of an end wall slotting device for a cascade test provided in an embodiment of this specification, referring to Fig.13As shown, an end wall slotting device for a cascade test provided in an embodiment of the present specification includes: a parameter determination module 100, a simulation calculation module 200, a result processing module 300, a separation data determination module 400, a slot parameter determination module 500, and a slotting processing module 600.

[0179] The parameter determination module 100 is used to obtain the geometric parameters of the cascade according to the size of the test bench and the target two-dimensional blade profile of the plane cascade test;

[0180] A simulation calculation module 200 is used to perform three-dimensional flow simulation calculation on the blade cascade using computational fluid dynamics based on the geometric parameters of the blade cascade;

[0181] The result processing module 300 is used to post-process the simulation calculation results to obtain the surface streamlines of the cascade;

[0182] A separation data determination module 400 is used to obtain separation data of the cascade angle zone separation according to the surface streamlines of the cascade;

[0183] A slot parameter determination module 500, for determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data and the slot parameters;

[0184] The machining and grooving module 600 is used to perform blade machining and end wall grooving based on the geometric parameters and groove parameters of the blade.

[0185] Reference Fig.14 As shown, based on the end wall slotting method of the blade cascade test described above, a computer device 1002 is also provided in one embodiment of the specification, wherein the above method is run on the computer device 1002. The computer device 1002 may include one or more processors 1004, such as one or more central processing units (CPUs) or graphics processing units (GPUs), and each processing unit may implement one or more hardware threads. The computer device 1002 may also include any memory 1006, which is used to store any kind of information such as code, settings, data, etc. In a specific implementation, a computer program on the memory 1006 and executable on the processor 1004, when the computer program is executed by the processor 1004, can execute instructions according to the above method.

[0186] Without limitation, for example, the memory 1006 may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, etc. More generally, any memory may use any technology to store information. Further, any memory may provide volatile or non-volatile retention of information. Further, any memory may represent a fixed or removable component of the computer device 1002. In one case, when the processor 1004 executes an associated instruction stored in any memory or a combination of memories, the computer device 1002 may perform any operation of the associated instruction. The computer device 1002 also includes one or more drive mechanisms 1008 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0187] The computer device 1002 may also include an input / output module 1010 (I / O) for receiving various inputs (via input device 1012) and for providing various outputs (via output device 1014). A specific output mechanism may include a presentation device 1016 and an associated graphical user interface 1018 (GUI). In other embodiments, the input / output module 1010 (I / O), input device 1012, and output device 1014 may not be included, and the computer device 1002 may be used as a computer device in a network. The computer device 1002 may also include one or more network interfaces 1020 for exchanging data with other devices via one or more communication links 1022. One or more communication buses 1024 couple the components described above together.

[0188] The communication link 1022 may be implemented in any manner, for example, through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 1022 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc. governed by any protocol or combination of protocols.

[0189] Corresponds to Figure 1 The method in the embodiment of the present specification also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are executed.

[0190] The embodiment of the present specification also provides a computer-readable instruction, wherein when the processor executes the instruction, the program therein causes the processor to execute the following Figure 1 The method shown.

[0191] The present specification also provides a computer program product. When the computer program product is executed by a processor of a computer device, the computer program product performs the following steps: Figure 1 The method shown.

[0192] The computer program product described in this specification is a software product that mainly implements the method described in this specification through a computer program.

[0193] It should be understood that in the various embodiments of this specification, the size of the serial numbers of the above-mentioned processes does not mean 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 this specification.

[0194] It should also be understood that in the embodiments of this specification, the term "and / or" is only a description of the association relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the embodiments of this specification generally indicates that the associated objects before and after are in an "or" relationship.

[0195] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the embodiments of this specification can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the embodiments of this specification.

[0196] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0197] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0198] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of this specification.

[0199] In addition, each functional unit in each embodiment of this specification may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0200] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of this specification is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of this specification. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0201] Specific embodiments are used in this specification to illustrate the principles and implementation methods of the embodiments of this specification. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of this specification. At the same time, for those skilled in the art, according to the ideas of the embodiments of this specification, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the embodiments of this specification.

Claims

1. A method for grooving an end wall of a cascade test, characterized in that: include: According to the size of the test bench and the target two-dimensional blade shape of the plane cascade test, the geometric parameters of the cascade are obtained; Based on the geometric parameters of the blade cascade, a three-dimensional flow simulation calculation is performed on the blade cascade using computational fluid dynamics; Post-process the simulation results to obtain the surface streamlines of the cascade; According to the surface streamlines of the cascade, separation data of the cascade angle zone separation is obtained; determining slot parameters of the cascade based on at least one of geometric parameters of the cascade, separation data, and slot parameters; Based on the geometric parameters and slot parameters of the blade row, blade row processing and end wall slotting are performed.

2. The method according to claim 1, characterized in that The geometric parameters of the blade cascade include: blade height, blade profile line scatter coordinates, chord length, consistency, aspect ratio, inlet geometric angle and installation angle.

3. The method according to claim 2, characterized in that The separation data of the cascade angle separation includes: a separation zone, a separation starting position, a separation center and a separation span range.

4. The method according to claim 3, characterized in that The slot parameters of the blade cascade include: slot outlet position, slot height, slot width and slot direction angle.

5. The method according to claim 3, characterized in that: The slot parameters of the blade cascade include: slot centerline position, slot width, slot start position, and slot end position.

6. The method according to claim 3, characterized in that The slot parameters of the blade grid include: vertical slot parameters and transverse slot parameters, wherein the vertical slot parameters include slot outlet position, slot height, slot width and slot direction angle, and the transverse slot parameters include slot centerline position, slot width, slot start position and slot end position.

7. The method according to claim 4 or 6, characterized in that: Determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data, and the slot parameters further comprises: According to the separation data of the blade cascade, the slot outlet position is set to be located at the separation center; According to the geometric parameters of the blade cascade, the groove height is set to 10% of the blade height; According to the geometric parameters of the blade cascade, the slot width is set to 1% chord length to 2% chord length; The slot inlet is arranged to be located on the pressure surface of the cascade according to the geometric parameters of the cascade, and the distance from the slot inlet to the leading edge of the cascade is greater than 50% of the chord length; According to the separation data of the blade cascade, the slot outlet is set to be located at the suction surface of the blade cascade, and the slot outlet position is located at the separation center; According to the positions of the slot inlet and the slot outlet, several alternative direction angles are obtained; The smallest of the several candidate direction angles is used as the groove direction angle.

8. The method according to claim 5, characterized in that Determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data, and the slot parameters further comprises: According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall; According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height; According to the geometric parameters of the blade cascade, the starting position of the groove is set to be at 60% of the chord length from the leading edge; According to the geometric parameters of the blade cascade, the end of the slot is set to be located at 90% of the chord length from the leading edge.

9. The method according to claim 6, characterized in that Determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data, and the slot parameters further comprises: According to the geometric parameters of the blade cascade, the center line of the groove is set at a distance of 5% of the blade height from the end wall; According to the geometric parameters of the blade cascade, the groove width is set to 2% of the blade height; Setting the slot outlet position of the blade cascade to the slot start position; According to the geometric parameters of the blade cascade, the end of the slot is set to be located at 90% of the chord length from the leading edge.

10. An end wall slotting device for cascade testing, characterized in that: The device comprises: A parameter determination module, for obtaining geometric parameters of the cascade according to the size of the test bench and the target two-dimensional blade profile of the plane cascade test; A simulation calculation module, used for performing three-dimensional flow simulation calculation on the blade cascade by using computational fluid dynamics based on the geometric parameters of the blade cascade; A result processing module is used to post-process the simulation calculation results to obtain the surface streamlines of the cascade; A separation data determination module, used for obtaining separation data of the cascade angle zone separation according to the surface streamline of the cascade; a slot parameter determination module, for determining the slot parameters of the cascade according to at least one of the geometric parameters of the cascade, the separation data and the slot parameters; The processing and grooving module is used to perform blade processing and end wall grooving based on the geometric parameters and groove parameters of the blade.

11. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that: When the computer program is executed by the processor, the computer program executes the instructions of the method according to any one of claims 1 to 9.

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