An integrated structure of an impeller machine and a design method thereof

Abstract

The application provides a kind of impeller machine integration structure and its design method, it is related to the technical field of impeller machine in aero-engine, gas turbine.The impeller machine integration structure includes casing (1), hub (2) and multiple blades (3), wherein: each blade (3) is fixedly connected to hub (2), multiple blades (3), hub (2) and the wall surface of casing (3) are surrounded to form multiple airflow channels, each airflow channel has the same geometric characteristics;Each blade (3) is arranged in the surrounding area of two adjacent airflow channels in the circumferential direction.The application directly obtains the airflow channel by stacking the flow surface of different flow direction positions along the flow direction, and then generates the blade geometry by the entity surrounded by two adjacent airflow channels, while the high-order smooth wall surface of flow channel can be realized more conveniently, the aerodynamic correlation of blade, end wall and flow channel can be realized, and then the design and control bottleneck of impeller machine angle area flow is broken through.

Description

Technical Field

[0001] This invention relates to the field of turbine technology in aero engines and gas turbines, and particularly to an integrated turbine structure and its design method. Background Technology

[0002] Rotating machinery such as compressors and turbines in aero-engines are collectively referred to as turbomachinery. Turbomachinery is a key core component for realizing the aerodynamic thermodynamic cycle of aero-engines, and its performance and technological level directly affect the overall engine development. Driven by the demand for higher thrust-to-weight ratios or power-to-weight ratios in aero-engines, high load, high pressure ratio, and high speed have become typical characteristics of advanced turbomachinery. This significantly enhances the three-dimensionality and distortion of flow within the blade passages, resulting in more distorted boundary layers on the blade and endwall surfaces. Flow separation and variation are more likely to occur at locations with abrupt curvature changes, such as corner regions, thus losing the proper flow characteristics of a turbomachinery and significantly reducing its aerodynamic performance. Typically, the direct cause of turbomachinery performance degradation lies in the deterioration of flow in the blade / endwall corner region. Overcoming this problem at its root requires focusing on organizing and controlling the complex three-dimensional flow in the blade / endwall corner region, weakening or avoiding corner separation.

[0003] To address the complex three-dimensional flow problems in the blade / endwall corner region, various flow control methods are typically employed to reduce flow losses. These include: altering the pressure gradient distribution in the corner region through blade sweep design, influencing the original secondary flow distribution and various vortex systems, thereby reducing corner flow losses; and appropriately modifying the local geometry of the turbine blade near the corner region or near the endwall through chamfering, non-axisymmetric endwalls, etc., to suppress complex flow in the corner region and thus reduce flow losses. However, in traditional turbomachinery design, blade sweep design and local flow control in the corner region are essentially post-hoc remedial measures. Traditional turbomachinery styling design methods stack blade profiles at different blade heights along the blade height direction to obtain the blade shape, with the channel between two adjacent blades serving as the airflow channel. Because this method treats the blade, endwall, and flow channel separately from the initial design stage, it cannot proactively consider the organization and control of complex flows in the blade / endwall corner region from the root. It can only add corresponding flow control methods after the design is completed, leading to higher design costs and failing to guarantee the universality and practicality of the flow control methods. Summary of the Invention

[0004] To avoid the inherent flow variation problems caused by separate blade and endwall designs, this invention provides an integrated turbomachinery structure and its design method. The integrated turbomachinery configuration proactively considers the complex flow in the blade / endwall corner region from the design source. By integrating the blade and endwall design, the aerodynamic correlation between the blade, endwall, and flow channel is achieved, thereby breaking through the design and control bottleneck of the turbomachinery corner region flow.

[0005] To achieve the above objectives, the present invention provides an integrated impeller structure, including a casing, a hub, and multiple blades, wherein: each blade is fixedly connected to the hub, and the walls of the multiple blades, the hub, and the casing surround and form multiple airflow channels, each airflow channel having the same geometric features; each blade is disposed in the circumferentially enclosed area of ​​two adjacent airflow channels.

[0006] Optionally, multiple blades are evenly distributed along the circumference.

[0007] Optionally, the geometric features of each airflow channel are obtained by stacking multiple S3 flow surfaces perpendicular to the streamline direction.

[0008] Optionally, the surface of each airflow channel is smooth and continuous.

[0009] Another aspect of the present invention provides a design method for an integrated structure of an impeller, the impeller including blades, a hub, and a casing. The method includes: forming multiple airflow channels by surrounding the walls of the blades, hub, and casing; uniformly distributing the multiple airflow channels along the circumferential direction; stacking multiple S3 flow surfaces perpendicular to the streamline direction in each airflow channel so that each airflow channel has the same geometric features; and generating blade geometry based on the surrounding area of ​​two adjacent airflow channels along the circumferential direction.

[0010] Optionally, the line connecting the centroids of multiple S3 flow surfaces constitutes the centerline of each airflow channel, and the centerline is determined by a preset centerline regularity function.

[0011] Optionally, apart from the inlet and outlet sections of the airflow channel, the shape curve of each S3 flow surface is generated by transforming the curvature of the cross-sectional lines.

[0012] Optionally, the shape curve of each S3 flow surface is generated by transforming the curvature of the cross-sectional lines, specifically including: discretizing the lines of the inlet and outlet cross-sections into I points of equal arc length to obtain the inlet cross-section point sequence and the outlet cross-section point sequence, where I ≥ 2 and is an integer; calculating the first and second derivatives corresponding to each cross-section point on the inlet and outlet cross-sections based on the inlet cross-section point sequence and the outlet cross-section point sequence to obtain the curvature of each cross-section point; correcting the curvature of each cross-section point through a preset cross-sectional shape transition law function to obtain the curve curvature distribution of each S3 flow surface; and generating the shape curve of the S3 flow surface based on the curve curvature distribution.

[0013] Optionally, the area of ​​multiple S3 flow surfaces can be controlled by a preset cross-sectional area variation function.

[0014] Optionally, the geometric features of each airflow channel are determined as follows: based on the shape curve of each S3 flow surface and the area of ​​multiple S3 flow surfaces, the shape curve of each S3 flow surface is enlarged proportionally to the area of ​​the corresponding S3 flow surface relative to the centroid of the cross section; based on the centerline law function, the enlarged S3 flow surfaces are arranged according to the axial position and circumferential offset to obtain multiple control sections; the multiple control sections are stacked along the streamline direction to obtain the geometric features of the airflow channel.

[0015] Compared with the prior art, the integrated impeller structure and its design method provided by the present invention have at least the following beneficial effects:

[0016] (1) This method can take into account the aerodynamic relationship between the blade and the endwall from the design source, avoid the deterioration of the blade / endwall corner flow caused by the traditional design method of treating the blade and endwall separately, realize the fine organization and control of the corner flow, and weaken or avoid flow separation.

[0017] (2) This method can make the flow channel walls such as blades and end walls blend smoothly in a high order by controlling the transformation law of the S3 flow surface, avoiding the discontinuity of the curvature of the blade and end wall surfaces caused by traditional design methods, thereby effectively improving the internal flow of the impeller.

[0018] (3) This invention provides an advanced turbomachinery design method that can be used to control complex three-dimensional flow, such as the corner region. It is easy to achieve efficient flow organization and control, and has strong design versatility. It is particularly suitable for various axial and centrifugal turbomachinery. Attached Figure Description

[0019] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic three-dimensional view of an integrated turbine structure according to an embodiment of the present invention is shown.

[0021] Figure 2 A flowchart illustrating the design method of an integrated turbomachinery structure according to an embodiment of the present invention is shown schematically.

[0022] Figure 3 A schematic diagram illustrating the geometric relationship of the centerline of the airflow channel according to an embodiment of the present invention is shown.

[0023] Figure 4 A flowchart illustrating the process of generating the shape curve of each S3 flow surface according to an embodiment of the present invention is shown schematically.

[0024] Figure 5 The diagram schematically illustrates the geometric relationship of the cross-sectional shape transition law function according to an embodiment of the present invention;

[0025] Figure 6 The diagram illustrates the geometric relationship of the function governing the change in cross-sectional area according to an embodiment of the present invention.

[0026] Figure 7 A flowchart illustrating the process of determining the geometric features of each airflow channel according to an embodiment of the present invention is shown schematically;

[0027] Figure 8 The diagram schematically illustrates the geometric relationships of multiple control sections according to an embodiment of the present invention;

[0028] Figure 9 A schematic diagram illustrating the geometric relationship between the airflow passage and the blades according to an embodiment of the present invention is shown.

[0029] [Explanation of Labels in the Attached Image]

[0030] 1-Casing; 2-Hub; 3-Blade. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0033] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0034] Figure 1 A schematic three-dimensional view of an integrated turbine structure according to an embodiment of the present invention is shown.

[0035] like Figure 1 As shown, the integrated impeller structure provided in this embodiment of the invention includes a casing 1, a hub 2, and multiple blades 3. The hub 2 can also be referred to as the lower end wall, and correspondingly, the casing 1 can also be referred to as the upper end wall.

[0036] Each blade 3 is fixedly connected to the hub 2. Multiple blades 3, hub 2 and casing 3 surround and form multiple airflow channels. Each airflow channel has the same geometric features. Each blade 3 is located in the area surrounded by two adjacent airflow channels along the circumferential direction.

[0037] Through the above structure, this embodiment takes into account the aerodynamic relationship between the blades, hub and casing solid wall surfaces in the design to maximize the adaptation to airflow characteristics. By integrating the blades and upper and lower end walls into an integrated design to generate airflow channels, the solid surrounding two adjacent airflow channels generates the blade geometry. This structure takes into account the aerodynamic relationship between the blades, hub and casing solid wall surfaces in the design to maximize the adaptation to airflow characteristics.

[0038] Furthermore, multiple blades 3 are evenly distributed along the circumference to ensure that the airflow is subjected to balanced forces within each blade.

[0039] Furthermore, the geometric features of each airflow channel are obtained by stacking multiple S3 flow surfaces perpendicular to the streamline direction.

[0040] Furthermore, the surface of each airflow channel is smooth and continuous.

[0041] Therefore, this structure can achieve high-order smooth integration of the flow channel walls such as blades and end walls by controlling the transformation law of the S3 flow surface, avoiding the discontinuity of the blade and end wall surface curvature caused by traditional design methods, thereby effectively improving the internal flow of the impeller.

[0042] This integrated impeller structure is simple, easy to design and manufacture, and easy to implement, without introducing new active flow control structures or additional flow losses.

[0043] Based on the above-disclosed structure, the present invention also provides a design method for the integrated structure of the impeller, which will be described below in conjunction with... Figures 2-9 The method is described in detail.

[0044] Figure 2 A flowchart illustrating the design method of an integrated turbomachinery structure according to an embodiment of the present invention is shown.

[0045] Combination Figure 1 and Figure 2 As shown, the impeller includes blades, a hub, and a casing. The design method of the integrated impeller structure according to this embodiment may include operation S210 to operation S230.

[0046] In operation of S210, multiple airflow channels are formed by surrounding the walls of the blades, hub, and casing, and these multiple airflow channels are evenly distributed along the circumferential direction.

[0047] In operation S220, multiple S3 flow surfaces perpendicular to the streamline direction in each airflow channel are stacked to make each airflow channel have the same geometric characteristics.

[0048] Therefore, by stacking S3 flow surfaces at different axial positions, an airflow channel can be directly obtained.

[0049] In operation S230, the blade geometry is generated based on the area enclosed by two adjacent airflow channels along the circumferential direction.

[0050] The blade geometry is generated by the solid enclosed by two adjacent airflow channels. In embodiments of this invention, S3 flow surfaces at different flow directions are stacked to directly obtain airflow channels, and then the blade geometry is generated by the solid enclosed by two adjacent airflow channels. This method considers the aerodynamic relationship between the blade and endwall from the design stage, effectively avoiding the flow deterioration in the blade / endwall corner region caused by the traditional design method of treating the blade and endwall separately, weakening or avoiding flow separation to maximize adaptation to airflow characteristics. Simultaneously, this method can also achieve high-order smooth integration of the flow channel walls such as the blade and endwall by controlling the transformation law of the S3 flow surface, avoiding the surface curvature discontinuities of the blade and endwall caused by traditional design methods, thereby effectively improving the internal flow of the turbomachinery.

[0051] In the process of realizing this invention, the inventors discovered that the effect of the impeller on airflow can be summarized in two aspects: 1) achieving a deflection of the airflow direction; 2) achieving expansion and acceleration or compression and deceleration of the airflow. Specifically, the deflection of the airflow direction is achieved by bending the centerline of the airflow channel, and the expansion or compression of the airflow is achieved by changing the area of ​​the flow surface of the airflow channel S3.

[0052] In view of this, in this embodiment of the invention, the line connecting the centroids of multiple S3 flow surfaces constitutes the centerline of each airflow channel, and the centerline is determined by a preset centerline regularity function y = f(x).

[0053] Figure 3 A schematic diagram illustrating the geometric relationship of the centerline of the airflow channel according to an embodiment of the present invention is shown.

[0054] like Figure 3 As shown, the central line regularity function y = f(x) can be represented by, for example, the following fifth-degree polynomial:

[0055] y = A + Bx + Cx 2 +Dx 3 +Ex 4 +Fx 5

[0056] Where x is the coordinate of the airflow passage of the impeller along the rotation axis, 0 < x < C ax C axy is the axial length of the blade; y is the offset of the centerline of the airflow channel at position x relative to the axis of y=0, and this offset is along the circumferential direction; A, B, C, D, E, and F are the constant, linear, quadratic, cubic, quartic, and quintic coefficients of the fifth-order polynomial, respectively.

[0057] Therefore, once the coefficients of the fifth-order polynomial are determined, the centerline of the airflow channel can be uniquely determined.

[0058] Since the airflow channels in the turbomachinery are uniformly distributed along the circumference and each channel has the same geometric characteristics, the constant term A of the fifth-degree polynomial of the centerline mentioned above depends only on the circumferential position of the airflow channels and is independent of the shape of the centerline. Therefore, the constant term coefficient A is any circumferential radian value between 0 and 2π. Optionally, A = 0 can be defined.

[0059] The coefficients of the fifth-degree polynomial are determined by the following pre-defined constraints:

[0060]

[0061] Where α1 is the inlet airflow angle of the airflow channel; α2 is the inlet airflow angle of the airflow channel; x m The axial coordinate of the blade at a preset fixed point; y m This is the y-axis coordinate of the preset fixed point.

[0062] The last constraint in the above-mentioned preset constraints is to ensure that there is no inflection point in the centerline of the airflow channel.

[0063] In the embodiments of the present invention, the determination of the preset constraints of the centerline regularity function y=f(x) is mainly based on the inlet airflow angle α1, the outlet airflow angle α2, the passage through the leading edge point (0,0), and a certain fixed point (x). m y m And thus determined.

[0064] It can be seen that at chord length C ax , airflow angles α1, α2, leading edge point (0, 0), and a fixed point (x m y m Given that all factors are known, the equation of the centerline regularity function y = f(x) has 6 unknown coefficients and 5 valid equations. Therefore, this centerline regularity function retains 1 degree of freedom in its parameters to adjust the shape of the centerline. Optionally, the coefficient B of the first-order term can be selected to control the rate of change and shape of the centerline, resulting in a centerline shape as shown below. Figure 3 As shown.

[0065] Optionally, each S3 flow surface constituting the airflow channel is a cross-section perpendicular to the rotation axis, i.e., each S3 flow surface is a parallel cross-section. The inlet cross-section shape of the airflow channel can be selected as a near-elliptical shape. The near-elliptical curve loop has the characteristics of smooth continuity, enabling smooth connection of the blade wall, hub wall, and casing wall in the airflow channel, resulting in better aerodynamic performance when the airflow passes through this cross-section. The outlet cross-section shape of the airflow channel can be selected as a near-quadrilateral shape, which helps control the wake loss at the blade trailing edge. Except for the inlet and outlet cross-sections, each S3 flow surface constituting the airflow channel is a transition cross-section between the inlet and outlet cross-section shapes.

[0066] In this embodiment of the invention, apart from the inlet and outlet sections of the airflow channel, the shape curve of each S3 flow surface is generated by transforming the curvature of the cross-sectional lines.

[0067] Figure 4 A flowchart illustrating the process of generating the shape curve of each S3 flow surface according to an embodiment of the present invention is shown schematically.

[0068] like Figure 4 As shown, the shape curve of each S3 flow surface is generated by transforming the curvature of the cross-sectional lines, which may specifically include the following operations S410 to S440.

[0069] In operation S410, the lines of the inlet and outlet sections are discretized into I points of equal arc length, respectively, to obtain the inlet section point sequence and the outlet section point sequence, where I ≥ 2 and are integers.

[0070] For example, by discretizing the lines of the elliptical cross-section at the inlet and the quadrilateral cross-section at the outlet into I points with equal arc lengths, the point sequence of the inlet cross-section (x) is obtained. in，i y in.i ) and exit section point sequence (x out，i y out.i ), where I≥2 and are integers, i=1,2,…,I.

[0071] During operation of S420, based on the inlet section point sequence and the outlet section point sequence, the first and second derivatives corresponding to each section point on the inlet and outlet sections are calculated to obtain the curvature of each section point.

[0072] Specifically, the curvature at each cross-section point is calculated using the following formula:

[0073]

[0074]

[0075] Where, k (in，i) and k (out，i)Let f'(in, i) and f'(out, i) be the curvatures of the i-th inlet section and the i-th outlet section, respectively, i = 1, 2, ..., I; f'(in, i) and f'(out, i) are the first derivatives of the i-th inlet section and the i-th outlet section, respectively; f″(in, i) and f″(out, i) are the second derivatives of the i-th inlet section and the i-th outlet section, respectively.

[0076] In operation S430, the curvature of each cross-section point is corrected by a preset cross-sectional shape transition law function to obtain the curve curvature distribution of each S3 flow surface.

[0077] Specifically, by introducing the cross-sectional shape transition law function m=g(x), the curvature distribution of each transition cross-section is calculated according to the following formula:

[0078] k (j，i) =k (in，i) +m (j) ·(k (out，i) -k (in，i) )

[0079] Where, k (j，i) Let m be the curvature distribution of the curve at the j-th transition section; (j) Let be the coefficient of the transition law function of the cross-sectional shape at the j-th transition cross-section.

[0080] In operation S440, the shape curve of the S3 flow surface is generated based on the curve curvature distribution.

[0081] After determining the distribution of the curvature k of each transition section with respect to the discrete points i of equal arc length, the geometry of the transition section of the airflow channel can be determined based on the curve curvature distribution.

[0082] Figure 5 The diagram illustrates the geometric relationship of the cross-sectional shape transition law function according to an embodiment of the present invention.

[0083] like Figure 5 As shown, in this embodiment of the invention, the cross-sectional shape transition law function m=g(x) adopts the following fifth-degree polynomial:

[0084] m = a + bx + cx 2 +dx 3 +ex 4 +fx 5

[0085] Where a, b, c, d, e, and f are the constant term, linear term, quadratic term, cubic term, quartic term, and quintic term coefficients of the quintic polynomial, respectively.

[0086] Since the transition curve of the cross-sectional shape generally has a rate of change of 0 at the inlet and outlet, and the value of m changes monotonically within the range of 0 to 1, a fixed intermediate transition cross-section (x) is selected. jc ,m(x jc Then, the coefficients of the fifth-degree polynomial of the above cross-sectional shape transition law function are determined according to the following preset constraints:

[0087]

[0088] Among them, C ax x is the axial length of the blade. jc Let m(x) be the axial coordinate of the blade at an intermediate transition section. jc (x) represents the intermediate transition section in the blade axial coordinate x. jc The function value of the transition law of the cross-sectional shape.

[0089] It can be seen that the equation of the above cross-sectional shape transition law function has 6 unknown coefficients and 5 valid equations. Therefore, this function leaves 1 parameter degree of freedom to adjust the shape curve of the S3 flow surface. Optionally, the quadratic term coefficient c is selected to control the curvature of the cross-sectional shape transition at the centerline, and the resulting curve shape of the cross-sectional shape transition law function is as follows. Figure 5 As shown.

[0090] Since the expansion or compression of airflow is achieved through the change in the area of ​​the airflow channel S3, in this embodiment of the invention, the area of ​​multiple S3 flow surfaces is controlled by a preset cross-sectional area change law function q = h(x).

[0091] Figure 6 The diagram illustrates the geometric relationship of the cross-sectional area variation function according to an embodiment of the present invention.

[0092] like Figure 6 As shown, in this embodiment of the invention, the function q = h(x) representing the change in cross-sectional area adopts a fifth-degree polynomial:

[0093] q = r + sx + tx 2 +ux 3 +vx 4 +wx 5

[0094] Where r, s, t, u, v, and w are the coefficients of the constant term, linear term, quadratic term, cubic term, quartic term, and quintic term of the quintic polynomial, respectively.

[0095] The coefficients of the fifth-degree polynomial are determined according to the following preset constraints:

[0096]

[0097] Among them, Cax A is the axial length of the blade. in and A out x represents the area of ​​the inlet and outlet cross sections, respectively; t and q t These are the blade axial coordinates and the corresponding cross-sectional area at the preset minimum cross-sectional area point.

[0098] The constraint conditions for the function q=h(x) which describes the change in cross-sectional area can be determined based on the inlet cross-sectional area A of the airflow channel. in Export cross-sectional area A out Passing through a certain extreme point of minimum cross-sectional area (x) t q t And thus determined.

[0099] It can be seen that the function q = h(x) representing the change in cross-sectional area has 6 unknown coefficients and 4 valid equations. Therefore, this function has 2 degrees of freedom to adjust the shape of the curve representing the change in cross-sectional area. Optionally, the coefficients s (first term) and t (second term) can be selected to control the rate of change and shape of the curve representing the change in cross-sectional area. The resulting curve represents the shape of the function representing the change in cross-sectional area. Figure 6 As shown.

[0100] Figure 7 A flowchart illustrating the process of determining the geometric features of each airflow channel according to an embodiment of the present invention is shown. Figure 8 The diagram schematically illustrates the geometric relationships of multiple control sections according to an embodiment of the present invention. Figure 9 A schematic diagram illustrating the geometric relationship between the airflow passage and the blades according to an embodiment of the present invention is shown.

[0101] Please see Figure 8 and Figure 9 ,right Figure 7 The process shown will be explained in detail.

[0102] like Figure 7 As shown, in this embodiment of the invention, the geometric features of each airflow channel can be determined according to the following operations S710 to S730.

[0103] In operation S710, based on the shape curve of the S3 flow surface and the area of ​​multiple S3 flow surfaces, the shape curve of each S3 flow surface is proportionally enlarged relative to the centroid of the cross section to the area of ​​the corresponding S3 flow surface.

[0104] Based on the shape curve of each S3 flow surface obtained by the cross-sectional shape transition law function m=g(x) and the cross-sectional area of ​​each S3 flow surface obtained by the cross-sectional area change law function q=h(x), the cross-sectional profile is enlarged proportionally to the corresponding cross-sectional area relative to the centroid of the cross-section.

[0105] When operating S720, according to the centerline law function, the enlarged S3 flow surfaces are arranged according to their axial position and circumferential offset to obtain multiple control sections.

[0106] Based on the aforementioned centerline regularity function y=f(x), the S3 flow surfaces after the above operation S710 are arranged according to their axial position and circumferential offset, resulting in multiple control sections with the following shapes: Figure 8 As shown.

[0107] In operation of S730, multiple control sections are stacked along the streamline direction to obtain the geometric features of the airflow channel.

[0108] like Figure 9 As shown, after obtaining the geometric features of the airflow channel, the airflow channel can be arrayed along the circumferential direction to obtain the blade shape, where the solid enclosed by two adjacent airflow channels is the blade geometry.

[0109] The above is merely an illustrative example, and the embodiments of the present invention are not limited thereto. For example, the embodiments of the present invention are implemented by combining the centerline regularity function, the cross-sectional shape transition regularity function, and the cross-sectional area change regularity function. These three regularity functions are all continuous functions. In some embodiments, the continuous function includes, but is not limited to, polynomial functions, B-spline curve functions, sine functions, cosine functions, etc.

[0110] For example, in some embodiments, the inlet cross-sectional shape of the airflow channel includes, but is not limited to, high-order continuous closed curves such as circles and ellipses, thereby achieving a smooth and continuous airflow channel.

[0111] For example, in some embodiments, the impeller blades formed by the above-described integrated impeller structure design method can complement existing impeller aerodynamic design technology or be used independently.

[0112] Based on the above disclosure, the embodiments of the present invention directly obtain the airflow channel by stacking the flow surfaces at different flow directions along the flow direction, and then generate the blade geometry through the solid enclosed by two adjacent airflow channels. At the same time, it can more easily achieve high-order smoothness of the flow channel wall. The present invention can proactively consider the integrated configuration of the impeller in the complex flow of the blade / endwall corner region from the design source. By integrating the design of the blade and endwall, the aerodynamic correlation of the blade, endwall and flow channel is realized, thereby breaking through the design and control bottleneck of the impeller corner region flow.

[0113] In summary, the integrated impeller structure and its design method provided by the embodiments of the present invention can achieve at least the following technical effects:

[0114] (1) Unlike the traditional turbomachine design method based on shaping the blade geometry, the method of this embodiment is based on the shaping design of the airflow channel;

[0115] (2) The design of the airflow channel is achieved through the centerline regularity function, the cross-sectional shape transition regularity function, and the cross-sectional area change regularity function. Based on these regularity functions, the shape and distribution of the regularity curve can be adjusted more flexibly.

[0116] (3) This method achieves aerodynamic correlation between blades, end walls and flow channels through integrated design of blades and end walls, and realizes smooth and continuous airflow channels, thereby better organizing and controlling complex flows such as blade / end wall corner areas from the root, and improving the performance level of the impeller.

[0117] (4) This method can make the flow channel walls such as blades and end walls blend smoothly in a high order by controlling the transformation law of the S3 flow surface, avoiding the discontinuity of the curvature of the blade and end wall surfaces caused by traditional design methods, thereby effectively improving the internal flow of the impeller.

[0118] (5) The integrated structure of the impeller is simple, easy to design and manufacture, and easy to implement, without introducing new active flow control structures or additional flow losses.

[0119] The accompanying drawings show some block diagrams and / or flowcharts. It should be understood that some blocks or combinations thereof in the block diagrams and / or flowcharts can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when executed by the processor, these instructions can create means for implementing the functions / operations described in these block diagrams and / or flowcharts.

[0120] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding the invention. Furthermore, the shape, size, and positional relationship of the components in the drawings do not reflect their actual size, scale, or actual positional relationship.

[0121] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0122] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for an integrated structure of an impeller, the impeller comprising blades, a hub, and a casing, characterized in that, The method includes: The walls of the blades, hub, and casing are surrounded to form multiple airflow channels, which are evenly distributed along the circumferential direction. Multiple S3 flow surfaces perpendicular to the streamline direction in each airflow channel are stacked to make each airflow channel have the same geometric features; Based on the circumferential enclosing area of ​​two adjacent airflow channels, the blade geometry is generated. The method achieves high-order smooth integration of the blade and endwall by controlling the transformation law of the multiple S3 flow surfaces. The line connecting the centroids of the plurality of S3 flow surfaces constitutes the centerline of each airflow channel, and the centerline is determined by a preset centerline regularity function; The inlet cross-sectional shape of the airflow channel is a high-order continuous closed curve, and the outlet cross-sectional shape of the airflow channel is a quadrilateral-like shape. Apart from the inlet and outlet cross-sections of the airflow channel, the shape curve of each S3 flow surface is generated by transforming the curvature of the cross-sectional lines, specifically including: Discretize the lines of the inlet and outlet sections into I points of equal arc length to obtain the inlet section point sequence and the outlet section point sequence, where I ≥ 2 and is an integer; Based on the inlet section point sequence and the outlet section point sequence, calculate the first and second derivatives corresponding to each section point on the inlet and outlet sections to obtain the curvature of each section point; By using a preset cross-sectional shape transition law function, the curvature of each cross-sectional point is corrected to obtain the curve curvature distribution of each S3 flow surface; Based on the curve curvature distribution, the shape curve of the S3 flow surface is generated; The area of ​​the multiple S3 flow surfaces is controlled by a preset cross-sectional area variation function; The geometric features of each of the airflow channels are determined according to the following method: Based on the shape curve of each S3 flow surface and the area of ​​the plurality of S3 flow surfaces, the shape curve of each S3 flow surface is enlarged proportionally to the area of ​​the corresponding S3 flow surface relative to the centroid of the cross section; Based on the centerline regularity function, the magnified S3 flow surfaces are arranged according to their axial positions and circumferential offsets to obtain multiple control sections; The geometric features of the airflow channel are obtained by stacking the multiple control sections along the streamline direction.

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