A method and system for optimizing strength of an axial flow rotor blade

Abstract

The application provides a kind of optimization method of axial rotor blade strength, comprising the following steps: design initial axial rotor blade scheme, and evaluate initial axial rotor blade scheme;The local range of the root of the initial axial rotor blade that meets the requirements after evaluation is thickened, the optimization of the strength of the axial rotor blade is completed, and the optimized axial rotor blade scheme is obtained;Three-dimensional modeling is carried out on the optimized axial rotor blade scheme, and the three-dimensional model of the optimized axial rotor blade is obtained;The three-dimensional model of the optimized axial rotor blade is evaluated, and the final optimization scheme is obtained after meeting the requirements.The blade strength is optimized by a simple method, the processing fine root problem is fundamentally avoided, the blade profile is within a reasonable range, the product processing qualification rate can be improved, and the manufacturing cost can be reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of axial flow impeller design, and particularly relates to a method and system for optimizing the strength of an axial flow rotor blade. BACKGROUND

[0002] For an engine with high rotational speed, the root stress level of the rotor blade is high, and sufficient strength reserve needs to be designed to meet the safe use requirements in the whole life cycle of the engine. In engineering applications, the blade design cannot be too thin or too thick, and only the optimal balance design of performance and strength can obtain an excellent engineering product. The existing design of the axial flow rotor blade usually adopts the equal Z or flow surface modeling design method, which has the following disadvantages when realizing the thickening of the blade root in a local height interval: the equal Z section or flow surface modeling cannot realize the thickness design adjustment in the height range corresponding to the non-equal Z or non-flow surface, which is easy to cause excessive or insufficient adjustment range. In view of the above problems, the application provides a method for quickly optimizing the strength of an axial flow rotor blade. SUMMARY

[0003] In view of the above problems, the application provides a method for optimizing the strength of an axial flow rotor blade, characterized in that the method comprises the following steps:

[0004] designing an initial axial flow rotor blade scheme and evaluating the initial axial flow rotor blade scheme;

[0005] thickening the local range of the blade root of the initial axial flow rotor blade that meets the requirements after evaluation, completing the optimization of the strength of the axial flow rotor blade, and obtaining an optimized axial flow rotor blade scheme;

[0006] performing three-dimensional modeling on the optimized axial flow rotor blade scheme to obtain a three-dimensional model of the optimized axial flow rotor blade;

[0007] evaluating the three-dimensional model of the optimized axial flow rotor blade, and obtaining a final optimization scheme after meeting the requirements.

[0008] Preferably, the evaluation of the initial axial flow rotor blade scheme comprises the following steps:

[0009] aerodynamic performance evaluation, in which a numerical simulation template that is calibrated by test data is used to evaluate the aerodynamic performance of the blade of the initial scheme;

[0010] strength evaluation, in which a numerical simulation template that is calibrated by test data is used to select the material properties to evaluate the strength of the rotor blade disc of the initial scheme, analyze the stress distribution, and analyze the strength reserve coefficient under the corresponding yield strength standard.

[0011] Preferably, the evaluation of the three-dimensional model of the optimized axial flow rotor blade comprises the following steps:

[0012] The aerodynamic performance of the optimized rotor blade is evaluated by using a numerical simulation template verified by test data, and compared with the initial axial flow rotor blade scheme.

[0013] The strength of the optimized rotor blade disc is evaluated by using a numerical simulation template verified by test data, and the stress distribution and strength reserve coefficient under the corresponding yield strength standard are analyzed, and compared with the initial axial flow rotor blade scheme.

[0014] Preferably, the yield strength standard is 0.75σ 0.1 .

[0015] Preferably, the method further comprises the following steps:

[0016] If the aerodynamic performance changes beyond the set range or the strength changes beyond the set range, repeat the following steps:

[0017] Thicken the local range of the blade root of the initial axial flow rotor blade that meets the requirements after evaluation, complete the optimization of the strength of the axial flow rotor blade, and obtain the optimized axial flow rotor blade scheme;

[0018] Three-dimensional modeling is performed on the optimized axial flow rotor blade scheme to obtain a three-dimensional model of the optimized axial flow rotor blade;

[0019] The three-dimensional model of the optimized axial flow rotor blade is evaluated until the aerodynamic performance and strength requirements are met.

[0020] Preferably, the method further comprises the following steps:

[0021] The maximum stress on the surface of the blade is located at the n1% blade height position, and the maximum proportion of the blade height in the high stress interval of 85% of the maximum stress value is n2%;

[0022] According to the maximum stress on the surface of the blade located at the n1% blade height position and the maximum proportion of the blade height in the high stress interval of 85% of the maximum stress value, the proportion n3% of the blade height in the thickening interval of the blade root is determined, including:

[0023] n3% = 2 x n2% - n1%;

[0024] According to the proportion n3% of the blade height in the thickening interval of the blade root and the meridian height of the blade leading edge, the blade height h that needs to be thickened is determined, including:

[0025] h = n3% x h B ;

[0026] Wherein, h B Meridian height of the blade leading edge, unit: mm.

[0027] Preferably, the blade height h that needs to be thickened is maximized under the condition of meeting aerodynamic performance.

[0028] Preferably, the optimization of the strength of the axial flow rotor blade is completed by thickening the local range of the blade root of the initial axial flow rotor blade, and further comprising the following steps:

[0029] In the corresponding height adjustment interval, the blade can be thickened by an equal amount along the corresponding height, including:

[0030] The root fillet of the blade connected to the disc is set as r, the intersection of the blade leading edge, trailing edge extension line and hub surface is axially away from the front end and rear end of the disc by t1 and t2, and the minimum value away from the front end and rear end of the disc is t min The calculation formula is:

[0031] t min = min(t1, t2);

[0032] According to the minimum value t min away from the front end and rear end of the disc and the root fillet r of the blade connected to the disc, the maximum thickness increment t is determined, including:

[0033] t = t min -r;

[0034] According to the yield strength standard x and the maximum stress value, the static strength reserve coefficient K of the rotor blade is determined, including:

[0035]

[0036] χ represents the yield strength standard;

[0037] According to the single-sided thickness adjustment of the nth time, the thickness increment d, the final thickness increment Δt is determined, including:

[0038] Δt = n x d.

[0039] Preferably, the optimized axial flow rotor blade is three-dimensionally modeled to obtain a three-dimensional model of the optimized axial flow rotor blade; including the following steps:

[0040] The determined height interval h of the local thickening of the blade root and the thickness increment Δt are used to thicken the local blade root of the initial scheme, and the fillet is rounded and smoothed at the connecting position to obtain a three-dimensional model of the optimized axial flow rotor blade scheme.

[0041] Preferably, the radius r of the rounding is maximized within the set range.

[0042] An axial flow rotor blade strength optimization system comprises:

[0043] A first calculation module is used for designing an initial axial flow rotor blade scheme and evaluating the initial axial flow rotor blade scheme;

[0044] A second calculation module is used for thickening a local range of a blade root of the initial axial flow rotor blade meeting the requirements after evaluation, completing optimization of the axial flow rotor blade strength, and obtaining an optimized axial flow rotor blade scheme;

[0045] A third calculation module is used for modeling the optimized axial flow rotor blade in three dimensions, and obtaining a three-dimensional model of the optimized axial flow rotor blade;

[0046] A fourth calculation module is used for evaluating the three-dimensional model of the optimized axial flow rotor blade, and obtaining a final optimization scheme after meeting the requirements.

[0047] The present application has the following beneficial effects:

[0048] 1. The present application optimizes the blade strength by a simple method, fundamentally avoids the problem of processing a fine root, makes the blade type within a reasonable range, and realizes the improvement of product processing qualification rate and the reduction of manufacturing cost.

[0049] 2. The present application keeps the number of original modeling sections unchanged, not only avoids the fairing design problem caused by local multi-section modeling design, but also quickly completes the strength optimization scheme and shortens the optimization design cycle.

[0050] 3. Generally, when the root Mach number is lower than 1.05, the height ratio of the root thickness adjustment is small, the thickness adjustment amount is limited, and the aerodynamic performance is basically not affected.

[0051] 4. The present application increases the rigidity of the blade root and the inherent frequency of the blade by thickening the local root, realizes the increase of resonance margin under the same speed, and reduces the risk of fracture caused by resonance.

[0052] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and obtained by the structure indicated in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0054] Figure 1 The optimized design process for improving blade strength in an embodiment of the present invention is shown.

[0055] Figure 2 A schematic diagram illustrating adjustment parameters during design optimization in an embodiment of the present invention is shown.

[0056] Figure 3 A schematic diagram of the meridian projection of a rotor blade before root adjustment in an embodiment of the present invention is shown.

[0057] Figure 4 A schematic diagram showing the maximum stress distribution on the surface of a rotor blade and the blade height ratio in an embodiment of the present invention is shown.

[0058] Figure 5 A schematic diagram of blade root thickness adjustment in an embodiment of the present invention is shown.

[0059] Figure 6 A schematic diagram of the meridian projection of the blade root thickening solution in an embodiment of the present invention is shown.

[0060] Figure 7 A schematic diagram of a three-dimensional model of a blade root thickening solution according to an embodiment of the present invention is shown.

[0061] Figure 8 The corresponding embodiment of the present invention is shown Figure 4 Schematic diagram of surface stress distribution after local thickening of the root of a blade in the example. DETAILED DESCRIPTION

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0063] like Figures 1-8 As shown, Figure 1 The optimized design process for improving blade strength in an embodiment of the present invention is shown. Figure 2 A schematic diagram illustrating adjustment parameters during design optimization in an embodiment of the present invention is shown. Figure 3 A schematic diagram of the meridian projection of a rotor blade before root adjustment in an embodiment of the present invention is shown. Figure 4 A schematic diagram showing the maximum stress distribution on the surface of a rotor blade and the blade height ratio in an embodiment of the present invention is shown. Figure 5 A schematic diagram of blade root thickness adjustment in an embodiment of the present invention is shown. Figure 6 A schematic diagram of the meridian projection of the blade root thickening solution in an embodiment of the present invention is shown.Figure 7 A three-dimensional model diagram of the thickened blade root according to an embodiment of the present application is shown. Figure 8 A three-dimensional model diagram of the thickened blade root according to an embodiment of the present application is shown. Figure 4 A surface stress distribution diagram of a thickened blade root according to an embodiment of the present application is shown. Figures 1-8 A method for optimizing the strength of an axial flow rotor blade, comprising the following steps:

[0064] Designing an initial axial flow rotor blade scheme; specifically, according to the index requirements, the scheme of the axial flow rotor blade disc is designed according to the method that has been mastered (for example, the equal Z-section or the flow surface modeling design method), the initial scheme before the thickness adjustment of the blade root is provided, and the initial axial flow rotor blade scheme is evaluated;

[0065] Thickening the blade root of the initial axial flow rotor blade that meets the requirements after the evaluation, and completing the optimization of the strength of the axial flow rotor blade;

[0066] Three-dimensional modeling of the optimized axial flow rotor blade scheme; obtaining the three-dimensional model of the optimized axial flow rotor blade;

[0067] Evaluating the three-dimensional model of the optimized axial flow rotor blade, and obtaining the final optimized scheme after meeting the requirements,

[0068] In the implementation of the present application, the evaluation of the initial axial flow rotor blade scheme comprises the following steps:

[0069] Aerodynamic performance evaluation, using a numerical simulation template (including grid, turbulence model, and preprocessing settings, etc.) that has been verified by test data, the aerodynamic performance of the blade of the initial scheme is evaluated, which is used as a comparison benchmark for the optimization design.

[0070] Strength evaluation, using a numerical simulation template (including grid, material properties, and preprocessing settings, etc.) that has been verified by test data, the strength of the rotor blade disc of the initial scheme is evaluated according to the corresponding material characteristics, the stress distribution and the strength reserve coefficient under the corresponding yield strength standard are analyzed, which is used as a comparison benchmark for the optimization design. The yield strength standard is 0.75σ 0.1 .

[0071] Evaluating the three-dimensional model of the optimized axial flow rotor blade, comprising the following steps:

[0072] Aerodynamic performance evaluation, using a numerical simulation template (including grid, turbulence model, and preprocessing settings, etc.) that has been verified by test data, the aerodynamic performance of the blade of the optimized scheme is evaluated, and the results are compared with those of the initial axial flow rotor blade scheme.

[0073] Strength evaluation, using the numerical simulation template (including grid, turbulence model and pre-processing settings, etc.) verified by test data, selecting the corresponding material properties to evaluate the strength of the initial scheme of a certain rotor blade disc, analyzing the stress distribution and strength reserve coefficient under the corresponding yield strength standard, and comparing with the initial axial flow rotor blade scheme results. Yield strength standard, take 0.75σ 0.1 .

[0074] If the aerodynamic performance changes exceed the allowed range or the strength changes exceed the allowed range, the steps of:

[0075] Thicken the local range of the initial axial flow rotor blade root that meets the requirements after evaluation, complete the optimization of the strength of the axial flow rotor blade, and obtain the optimized axial flow rotor blade scheme;

[0076] Three-dimensional modeling of the optimized axial flow rotor blade scheme; obtain the three-dimensional model of the optimized axial flow rotor blade;

[0077] Evaluate the three-dimensional modeling of the optimized axial flow rotor blade until the aerodynamic performance and strength requirements are met.

[0078] Specifically, if the aerodynamic performance changes exceed the allowed range, the steps of thickening the local range of the initial axial flow rotor blade root design scheme to complete the optimization of the strength of the axial flow rotor blade and three-dimensional modeling of the optimized axial flow rotor blade scheme need to be repeated, and re-evaluation until the aerodynamic performance requirements are met.

[0079] Specifically, if the strength changes exceed the allowed range, the steps of thickening the local range of the initial axial flow rotor blade root design scheme to complete the optimization of the strength of the axial flow rotor blade and three-dimensional modeling of the optimized axial flow rotor blade scheme need to be repeated, and re-evaluation until the dual requirements of strength reserve are met.

[0080] Only when the dual requirements of strength reserve and aerodynamic performance are met, can the design meet the requirements.

[0081] In the above embodiment, optionally another embodiment is that the optimization of the initial axial flow rotor blade scheme height includes the following steps:

[0082] The maximum stress of the blade surface is located at the n1% blade height position; the maximum proportion of the blade height of the high stress interval with a maximum stress value of 85% is n2%. Then the height adjustment range of the blade root thickness should cover the high stress interval;

[0083] The proportion of the blade height of the blade root thickening interval is usually determined according to the following formula:

[0084] n3% = 2 x n2% - n1%;

[0085] The blade height to be thickened is determined according to the following formula:

[0086] h = n3% x h B ;

[0087] Wherein, h B is the meridian height of the blade leading edge, unit mm.

[0088] In the case of meeting the aerodynamic performance, the height of the thickening interval can be appropriately increased according to the needs, and the blade height h to be thickened takes the maximum value.

[0089] In the above embodiment, another optional implementation is that,

[0090] The optimization of the strength of the axial flow rotor blade is completed by thickening the local range of the blade root of the initial axial flow rotor blade, and further comprises the following steps:

[0091] In the corresponding height adjustment interval, the blade can be thickened by an equal amount along the corresponding height, and the specific adjustment steps are as follows:

[0092] The root fillet of the blade connected with the disc is set as r, the intersection point of the blade leading edge and trailing edge extension line and the hub surface, the axial distance from the front end and the rear end of the disc is t1 and t2 respectively, and the minimum value from the front end and the rear end of the disc is t nin The calculation formula is:

[0093] t min = min(t1, t2);

[0094] The calculation formula of the maximum thickness increment t allowed is:

[0095] t = t min -r;

[0096] The formula for determining the static strength reserve coefficient of the rotor blade:

[0097] χ represents the yield strength standard, and χ takes the value of 0.75σ 0.1 .

[0098] The calculation formula of the final thickness increment Δt in the range allowed by the maximum value and under the condition allowed by the aerodynamic performance is:

[0099] Δt = n x d;

[0100] Wherein, n is the single-sided thickness adjustment of the nth time, and the thickness increment d is related to the relative Mach number of the gas flow at the blade root.

[0101] The above optimized axial flow rotor scheme is modeled in three dimensions, including the following steps:

[0102] Determine the height interval h and thickness increment Δt of the local thickening of the blade root, select appropriate modeling software, and thicken the initial blade root locally in the initial scheme. Then, round off the transition position and fair the transition to obtain a three-dimensional model of the optimized axial rotor blade scheme.

[0103] To reduce stress concentration on the blade surface, the rounding radius value should be the maximum within the specified range.

[0104] This design method is based on the initial scheme of the axial rotor blade that has been completed. The numerical simulation method that has been tested and verified is used to evaluate the aerodynamic performance and the strength of the blade disc. The relationship between the maximum stress value of the blade root and the material yield strength σ 0.1 is analyzed and evaluated to determine the thickness increment and height adjustment scheme of the blade root. After modeling, the same simulation settings are used to evaluate the aerodynamic performance and the strength of the blade. Multiple rounds of adjustment scheme iteration may be required during the process until the aerodynamic performance and strength reserve factor meet the evaluation criteria or the target results are improved. This design method can quickly determine the local thickening scheme of the blade root and significantly improve the strength reserve factor without changing the blade performance. The technology can be applied to the design of fan, blower, air compressor, pump, and gas turbine engine compressor rotor blades.

[0105] Step 1: Complete the initial design of the axial rotor blade disc;

[0106] According to the index requirements, the method (such as equal Z-section or flow surface modeling design method) that has been mastered is used to complete the design of the axial rotor blade disc to provide the initial scheme before the thickness of the blade root is adjusted.

[0107] Step 2: Initial scheme evaluation;

[0108] Aerodynamic performance evaluation: The numerical simulation template (including mesh, turbulence model, and preprocessing settings) that has been tested and verified is used to evaluate the aerodynamic performance of the initial scheme of the rotor blade, which serves as the baseline for optimization design.

[0109] Strength evaluation: The numerical simulation template (including mesh, material properties, and preprocessing settings) that has been tested and verified is used to evaluate the strength of the initial scheme of the rotor blade disc. The stress distribution and strength reserve factor under the corresponding yield strength standard are analyzed to serve as the baseline for optimization design.

[0110] Yield strength standard: 0.75σ 0.1 .

[0111] Step 3: Method for optimizing the initial scheme;

[0112] The adjustment scheme for blade strength optimization design includes the adjustment height and thickness increment of the local thickness of the blade root, and the adjustment parameter description is shown. Figure 2 Due to the constraints of the compressor's aerodynamic performance, the blade thickness adjustment height and thickness increment cannot be too large, and are specifically selected according to the following formula.

[0113] Adjust the height,

[0114] According to the blade strength assessment results of the initial scheme, the blade height ratio of the maximum stress value of the blade and the maximum blade height ratio of the high stress range of 85% of the maximum stress value are determined.

[0115] Assuming the maximum stress on a blade surface is located at n1% of the blade height, and the maximum percentage of the blade height within the high-stress range of 85% of the maximum stress value is n2%, the blade root thickness adjustment range should cover this high-stress range. Analysis suggests that the percentage of blade height required for increased blade root thickness is typically determined using formula (1), and the adjusted blade height can then be determined using formula (2).

[0116] n3%=2×n2%-n1%(1);

[0117] The adjusted blade height is determined by the following formula:

[0118] h=n3%×h B (2);

[0119] Among them, h B is the meridian height of the leading edge of the blade, in mm.

[0120] by Figure 3 For example, consider a rotor blade shown in the figure. The maximum stress on the blade surface is 722 MPa (based on a material standard stress of 760 MPa, the strength reserve coefficient is 1.05). This stress is located at 5% (n1%) of the blade height. The high stress interval corresponding to 85% of the maximum stress value does not exceed 7% (n2%). Therefore, the root thickness should be increased within 9% (n3%) of the blade height. If the leading edge height is 50 mm, the blade thickness adjustment range is 4.5 mm.

[0121] It should be noted that, according to the results of numerical simulation evaluation, if aerodynamic performance permits, the height adjustment amount can be appropriately increased as needed.

[0122] Thickness increment,

[0123] Within the corresponding height adjustment range, the blade thickness can be increased by an equal amount along the corresponding height, or the thickness can be adjusted in different increments along the corresponding blade height. The thickness increment value is subject to the dual constraints of aerodynamic performance and structural dimensions. Usually, the equal amount of thickening is selected for adjustment, so taking the equal amount of thickening adjustment as an example, the specific adjustment steps are described as follows:

[0124] Assuming that the root fillet angle of the blade connecting to the disk is r, the intersection of the leading edge and trailing edge extension lines of the blade and the hub surface is t1 and t2 from the front and rear ends of the disk respectively. The minimum value is t according to formula (3). min , then the maximum allowable thickness increment t can be determined according to formula (4). The static strength reserve coefficient of the rotor blade is determined according to formula (5). Within the maximum allowable range and under the conditions of aerodynamic performance, the final thickness increase Δt can be determined according to formula (6). Where n is the nth unilateral thickness adjustment, and the thickness increment d is related to the relative Mach number of the gas flow at the blade root. The reference values ​​are shown in Table 1.

[0125] t min =min(t1, t2)(3);

[0126] The calculation formula for the maximum allowable thickness increment t is:

[0127] t=t min -r(4);

[0128] The formula for determining the static strength reserve coefficient of the rotor blade is:

[0129]

[0130] Within the maximum allowable range and under the conditions of aerodynamic performance, the calculation formula for the final thickness increment Δt is:

[0131] Δt=n×d(6);

[0132] Table 1 Thickness increment value reference

[0133]

[0134]

[0135] by Figure 3 Taking a rotor blade shown as an example, the strength reserve coefficient evaluated according to the corresponding material is 1.05, the blade root thickness increment d is 0.03mm, and the thickening amount determined by two adjustments is 0.06mm.

[0136] Step 4: 3D modeling of the optimized solution;

[0137] According to step 3: the method of optimizing the initial scheme; determine the height h and thickness increment Δt of the root thickening adjustment, select appropriate modeling software, thicken the root area of the initial scheme, and then round and smooth the transition position.

[0138] Wherein, the selection of the rounding radius is affected by the complexity of the initial scheme blade shape and the thickness increment size, but it should be as large as possible to reduce the stress concentration on the blade surface. The meridian projection view and three-dimensional model of the final local thickening scheme of the blade root are respectively Figure 5 、 Figure 6 .

[0139] Step 5: optimization scheme evaluation and iteration

[0140] For the blade profile after local thickening of the blade root, the numerical simulation method consistent with step 2: initial scheme evaluation is used to evaluate the aerodynamic performance and blade strength, and the results are compared with the previous optimization scheme results.

[0141] If the aerodynamic performance changes exceed the allowed range, it is necessary to return to step 3: the method of optimizing the initial scheme; according to the adjustment scheme evaluation results, reduce the thickness increment or height adjustment interval, re-evaluate until the dual requirements of aerodynamic performance and strength reserve are met.

[0142] For example, as shown in Figure 7 , after the local thickening of the blade root, the maximum stress is 706 MPa, which is reduced by 2.22%; the corresponding material strength reserve coefficient is 1.076, which is increased by 2.27%, which meets the requirements according to the use condition requirements, and does not need to be adjusted.

[0143] According to the experience of multiple scheme numerical simulation comparison, when the blade root Mach number is within 1.05, the single-sided thickness increment of the blade root is usually within 0.10 mm, and the aerodynamic performance change caused by the thickening scheme within 10 mm above the blade root is very small, which can be directly applied.

[0144] The above optimization scheme is also applicable to small and medium-sized aviation gas turbine engines,

[0145] The small and medium-sized aero gas turbine engine has a small structure size, a high design working speed, and is usually above 30000r / min. The rotating blade has a high root stress under the influence of bending stress and tensile stress. In order to reduce the root stress of the blade, measures can be taken from reducing the torsional complexity of the blade design, reducing the number of blades, or reducing the thickness of the blade to reduce the weight. With the improvement of the performance demand index of the compressor, the compressor gradually develops towards the high pressure ratio and high flow capacity technology, and it is urgent to use a more complex blade profile with higher performance, and a relatively thin blade is needed to obtain higher aerodynamic performance. The number of blades directly affects the load level and the ability to resist the pressure gradient of the blade, and then affects the stable working margin of the compressor. At the same time, although the thinning of the blade reduces the tensile stress caused by the centrifugal force by reducing the weight of the blade, the stress of the root of the thin blade still increases inevitably. Therefore, a single technical measure cannot achieve the best balance between aerodynamic performance and strength reserve, and multiple technical measures must be taken from design and working conditions to obtain the best product that can be well applied in engineering.

[0146] The patent presented in the basic does not change the original aerodynamic design, through the local thickening of the blade root, not only avoids the fairing design problem brought by the conventional small range thickening design, but also has the characteristics of short cycle and quick effect. The result not only has no influence on the aerodynamic performance of the compressor, but also can realize the obvious reduction of the blade root stress, so as to significantly improve the strength reserve of the blade, and fundamentally avoid the problem of processing thin root and improve the processing qualification rate of the part.

[0147] Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0148] An optimization system for the strength of an axial flow rotor blade, characterized in that it comprises:

[0149] A first calculation module for designing an initial axial flow rotor blade scheme and evaluating the initial axial flow rotor blade scheme;

[0150] A second calculation module for thickening in a local range of the blade root of the initial axial flow rotor blade that meets the requirements after evaluation to complete the optimization of the strength of the axial flow rotor blade and obtain an optimized axial flow rotor blade scheme;

[0151] A third calculation module for three-dimensional modeling of the optimized axial flow rotor blade scheme to obtain a three-dimensional model of the optimized axial flow rotor blade;

[0152] Fourth calculation module: evaluate the optimized axial flow rotor blade three-dimensional modeling, and get the final optimization scheme after meeting the requirements.

Claims

1. A method for optimizing the strength of an axial flow rotor blade, characterized in that: The following steps are involved: Design and evaluate initial axial flow rotor blade solutions; The root area of ​​the initial axial flow rotor blade that meets the requirements after evaluation is locally thickened to complete the optimization of the axial flow rotor blade strength and obtain the optimized axial flow rotor blade scheme; Perform three-dimensional modeling on the optimized axial flow rotor blade scheme to obtain the optimized three-dimensional model of the axial flow rotor blade; Evaluate the optimized 3D model of the axial flow rotor blades and obtain the final optimization solution if it meets the requirements; The root of the initial axial flow rotor blade that meets the requirements after evaluation is locally thickened to complete the optimization of the axial flow rotor blade strength and obtain an optimized axial flow rotor blade scheme; the steps include: Assume that the maximum stress on the blade surface is located at the %Leaf height position; The maximum proportion of leaf height in the high stress interval of 85% of the maximum stress value is %; According to the maximum stress on the blade surface, the %The maximum proportion of leaf height at leaf height position and high stress interval of 85% of maximum stress value %, determine the proportion of leaf height in the leaf root thickening range %,include: %=2× %- %； According to the leaf height ratio of the leaf root thickening range % and the meridian height of the leading edge of the blade to determine the blade height h that needs to be thickened, including: h= %× ； in, is the meridian height of the leading edge of the blade, in mm.

2. The method for optimizing the strength of an axial flow rotor blade according to claim 1, characterized in that: The evaluation of initial axial flow rotor blade concepts involves the following steps: Aerodynamic performance evaluation: using numerical simulation templates verified with test data to evaluate the aerodynamic performance of the initial blade design; Strength assessment: Using a numerical simulation template verified by test data, the corresponding material properties are selected to conduct strength assessment of the rotor blade disk of the initial scheme, and its stress distribution and strength reserve coefficient under the corresponding yield strength standard are analyzed.

3. The method for optimizing the strength of an axial flow rotor blade according to claim 1, characterized in that: The evaluation of the optimized 3D model of the axial-flow rotor blade includes the following steps: Aerodynamic performance evaluation: Using numerical simulation templates verified with test data, the aerodynamic performance of the optimized rotor blades is evaluated and compared with the initial axial flow rotor blade solution; Strength assessment: Using a numerical simulation template verified by test data, the corresponding material properties are selected to conduct strength assessment of the rotor blade disk of the optimized solution, analyze its stress distribution and strength reserve coefficient under the corresponding yield strength standard, and compare it with the initial axial flow rotor blade solution.

4. The method for optimizing the strength of an axial flow rotor blade according to claim 2 or 3, characterized in that: The yield strength standard is .

5. The method for optimizing the strength of an axial flow rotor blade according to claim 4, characterized in that: It also includes the following steps: If the aerodynamic performance changes outside the set range or the strength changes outside the set range, repeat the following steps: The root area of ​​the initial axial flow rotor blade that meets the requirements after evaluation is locally thickened to complete the optimization of the axial flow rotor blade strength and obtain the optimized axial flow rotor blade scheme; Perform three-dimensional modeling on the optimized axial flow rotor blade scheme to obtain the optimized three-dimensional model of the axial flow rotor blade; The optimized axial flow rotor blades are evaluated in 3D modeling until they meet the aerodynamic performance and strength requirements.

6. The method for optimizing the strength of an axial flow rotor blade according to claim 1, characterized in that: The optimization of the strength of the axial flow rotor blade is achieved by thickening a local area of ​​the blade root of the initial axial flow rotor blade, and further includes the following steps: Within the corresponding height adjustment range, the blade can be thickened by equal amounts along the corresponding height, including: The root fillet angle where the blade meets the disk is set to r, and the axial distances from the intersection of the leading and trailing edge extension lines of the blade and the hub surface to the front and rear ends of the disk are respectively , the minimum distance from the front and back ends of the wheel is The calculation formula is: =min( ); The minimum distance from the front and back ends of the wheel is The maximum thickness increment t is determined by the fillet r of the root where the blade meets the disk, including: t= -r； Determine the static strength reserve factor K of the rotor blade based on the yield strength standard x and the maximum stress value, including: K= ； χ represents the yield strength standard; According to the nth unilateral thickness adjustment, thickness increment d, the final thickness increment Δt is determined, including: Δt=n×d.

7. The method for optimizing the strength of an axial flow rotor blade according to claim 1, characterized in that: The optimized axial flow rotor blade is three-dimensionally modeled to obtain the optimized axial flow rotor blade three-dimensional model; the steps include: The height interval h and thickness increment Δt of the local thickening of the blade root are determined, the blade root of the initial scheme is locally thickened, and then the connecting position is rounded and smoothly transferred to obtain the three-dimensional model of the optimized axial flow rotor blade scheme.

8. The method for optimizing the strength of an axial flow rotor blade according to claim 7, characterized in that: The fillet radius r takes the maximum value within the set range.

9. An axial flow rotor blade strength optimization system, characterized in that: include: The first calculation module is used to design an initial axial flow rotor blade scheme and evaluate the initial axial flow rotor blade scheme; The second calculation module: thickens the local area of ​​the blade root of the initial axial flow rotor blade that meets the requirements after evaluation, completes the optimization of the axial flow rotor blade strength, and obtains the optimized axial flow rotor blade scheme; The third calculation module is used to perform three-dimensional modeling on the optimized axial flow rotor blades to obtain a three-dimensional model of the optimized axial flow rotor blades; The fourth calculation module evaluates the optimized axial flow rotor blade three-dimensional model and obtains the final optimization solution if it meets the requirements. The root of the initial axial flow rotor blade that meets the requirements after evaluation is locally thickened to complete the optimization of the axial flow rotor blade strength and obtain an optimized axial flow rotor blade scheme; the steps include: Assume that the maximum stress on the blade surface is located at the %Leaf height position; The maximum proportion of leaf height in the high stress interval of 85% of the maximum stress value is %; According to the maximum stress on the blade surface, the %The maximum proportion of leaf height at leaf height position and high stress interval of 85% of maximum stress value %, determine the proportion of leaf height in the leaf root thickening range %,include: %=2× %- %； According to the leaf height ratio of the leaf root thickening range % and the meridian height of the leading edge of the blade to determine the blade height h that needs to be thickened, including: h= %× ； in, is the meridian height of the leading edge of the blade, in mm.

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