High-load diffusion cascade structure with local non-smooth resistance reduction rib surface and design method of high-load diffusion cascade structure

Abstract

The invention provides a high-load diffusion cascade structure with local non-smooth resistance reduction rib surfaces and a design method thereof, the diffusion cascade structure is a planar cascade structure or an annular cascade structure, and the non-smooth resistance reduction rib surfaces are arranged on the planar cascade structure and the annular cascade structure. Various resistances in a cascade channel can be controlled, so that separation and vortex loss caused by resistance increase, mixing loss of main flow and backflow and friction loss of airflow and blade wall surfaces are reduced, and the performance of the gas compressor is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of turbomachinery, and in particular to a high-load diffuser blade structure with a local non-smooth drag-reducing rib surface and a design method thereof. Background Art

[0002] Drag reduction technology has always been the focus, emphasis and hotspot of research in the field of fluid mechanics. Commonly used drag reduction methods mainly include active drag reduction and passive drag reduction. Active drag reduction includes wall vibration drag reduction, bionic jet drag reduction, fluid displacement and air suction, etc. Passive drag reduction mainly includes bionic non-smooth surface drag reduction, hydrophobic surface drag reduction, polymer drag reduction and compliant wall drag reduction. Active drag reduction technology can achieve different degrees of control of flow separation and turbulent vortex through active adjustment, thereby changing the motion state in the flow field. It has good applicability to working conditions, but it requires the addition of additional devices and energy sources, which not only consumes additional energy, but also increases the difficulty of design. Passive drag reduction does not require external application of additional momentum or energy, but only needs to change the surface geometry according to demand. It has the advantages of simple structure, low design cost and easy implementation. Whether it is active or passive drag reduction, rationally organizing flow, reducing resistance, suppressing separation and improving performance are the core of its work. For compressors, which are machines with high design difficulty, highly complex structure and extremely harsh working conditions, passive drag reduction methods with simple structures have great application potential.

[0003] The loss caused by resistance inside the compressor has an important influence on the further improvement of the overall performance. Therefore, the reduction of resistance is of great significance for the improvement of various blades or the performance of the whole machine. The types of resistance in the compressor mainly include friction resistance and pressure difference resistance. Friction resistance includes viscous friction resistance and Reynolds stress. The diffuser cascade, as the basis of the design of the compressor blade or blade, is directly related to the performance of the compressor. The performance requirements of modern advanced gas turbines have further increased the load of the compressor. Under the premise of limited number of stages and trying not to increase the weight, the increase in stage load makes the single-stage pressure ratio of the compressor higher and the blade aspect ratio smaller. This makes it easier for boundary layer separation to occur in the compressor flow channel. The airflow separation will cause a sharp increase in the Reynolds stress and pressure difference resistance of the airflow. At the same time, the various concentrated vortex systems will cause huge mixing losses, leading to a series of adverse effects such as compressor blockage and reduced efficiency. Therefore, taking effective measures to reduce the various resistances inside the compressor and further control or weaken the flow separation and related losses in the compressor are of great significance to further improve the performance of the compressor and even the gas turbine. Summary of the invention

[0004] According to the technical problems raised above, a high-load diffuser blade structure with a local non-smooth drag reduction rib surface and a design method thereof are provided. The present invention mainly obtains a diffuser blade structure with a non-smooth drag reduction rib surface by adjusting the microstructure form and arrangement position of the non-smooth drag reduction rib surface, thereby achieving passive drag reduction, while weakening the separation strength of the corner area in the blade channel, reducing the vortex loss, mixing loss and friction loss between the airflow and the blade surface caused by separation, and thus improving the diffuser capacity of the blade.

[0005] The technical means adopted by the present invention are as follows:

[0006] A high-load diffuser blade structure with a local non-smooth drag-reducing rib surface, wherein the diffuser blade structure is a plane blade structure or an annular blade structure, and the plane blade structure and the annular blade structure are provided with a non-smooth drag-reducing rib surface.

[0007] Further, the plane cascade structure comprises a plane cascade cascade plate and a blade, the blade is fixedly connected to the plane cascade cascade plate through a blade profile groove arranged on the plane cascade cascade plate, and the non-smooth drag reduction rib surface is arranged on the blade alone; or, the non-smooth drag reduction rib surface is arranged on the plane cascade cascade plate alone; or, the non-smooth drag reduction rib surface is arranged on both the blade and the plane cascade cascade plate;

[0008] The non-smooth drag reducing rib surface is locally present on the blade and / or the planar cascade panel.

[0009] Further, the annular blade cascade structure includes a casing, a hub and blades, and the non-smooth drag reduction rib surface is arranged on the blade alone; or, the non-smooth drag reduction rib surface is arranged on the casing or the hub alone; or, the non-smooth drag reduction rib surface is arranged on the blade and the casing at the same time; or, the non-smooth drag reduction rib surface is arranged on the blade and the hub at the same time; or, the non-smooth drag reduction rib surface is arranged on the blade, the casing and the hub at the same time;

[0010] The non-smooth drag reduction rib surface exists locally on the blade, casing or hub; or, the non-smooth drag reduction rib surface exists locally on the blade and casing; the non-smooth drag reduction rib surface exists locally on the blade and hub; or, the non-smooth drag reduction rib surface exists locally on the casing and hub; or, the non-smooth drag reduction rib surface exists locally on the blade, casing and hub.

[0011] Furthermore, the non-smooth drag reduction rib surface on the blade is a structure composed of an array of transverse micro-rib structures arranged at an angle of 90° to the flow direction, and the non-smooth drag reduction rib surface on the planar cascade plate is a structure composed of an array of transverse or flow-direction micro-rib structures.

[0012] Furthermore, the non-smooth drag-reducing rib surface on the blade is a structure composed of an array of transverse micro-rib structures arranged at an angle of 90° to the flow direction, and the non-smooth drag-reducing rib surface on the casing and the hub is a structure composed of an array of transverse or flow-direction micro-rib structures.

[0013] Furthermore, the cross-sectional shape of the micro-rib structure is a regular shape, a partially irregular shape or an asymmetric shape, the regular shape at least includes a rectangle, an isosceles trapezoid, a V shape, and an arc shape, the partially irregular shape at least includes an angled V shape, and the asymmetric shape at least includes a high-order curve shape;

[0014] The micro-rib structure is in the form of a groove structure or a protrusion structure.

[0015] The present invention also provides a design method for a high-load diffuser blade structure with a local non-smooth drag reduction rib surface, comprising the following steps:

[0016] S1. Determine the incoming flow conditions according to the selected compressor or cascade working conditions, and the dimensionless width w of the micro-rib structure + , dimensionless height d + , the actual size of the micro-rib structure is determined in combination with the incoming flow conditions, and the width and depth of the micro-rib structure are obtained;

[0017] S2, determining the cross-sectional shape of the micro-rib structure according to the width and depth of the micro-rib structure obtained in step S1;

[0018] S3. After the cross-sectional shape of the micro-rib structure is determined, numerical calculations are performed to determine the spacing and coverage range, and combined with the corresponding position parameters, the arrangement form of the micro-rib structure on the plane blade structure or the annular blade structure is finally determined, and the array arrangement is combined into the profile of the non-smooth drag reduction rib surface; then, a new blade profile with a non-smooth drag reduction rib surface profile is generated by combining the original blade profile with a drawing software, and a corresponding blade profile with a non-smooth drag reduction rib surface is generated by a three-dimensional drawing software, and the corresponding high-load expansion blade structure is obtained by combining the blade profile installation angle and pitch parameters.

[0019] Further, in step S1, the incoming flow condition at least includes the incoming flow Mach number and Reynolds number;

[0020] Dimensionless width w + , dimensionless height d + Satisfies the following formula:

[0021]

[0022] In the formula, μ τ is the wall shear velocity, w is the actual width, d is the actual height, and v is the kinematic viscosity;

[0023] Wall shear velocity μ τ Satisfies the following formula:

[0024]

[0025] In the formula, is the near-wall shear stress, ρ is the density;

[0026] Near-wall shear stress Satisfies the following formula:

[0027]

[0028] Where V ∞ is the incoming flow velocity, σ is the shear stress near the wall;

[0029] The near-wall shear stress σ satisfies the following formula:

[0030] σ=0.37×(Re b ) 0.2 ;

[0031] In the formula, Re b is the Reynolds number, b is the characteristic length, i.e. the blade chord length;

[0032] Reynolds number b Satisfies the following formula:

[0033]

[0034] The width and depth of the final micro-rib structure satisfy the following formula:

[0035]

[0036] Furthermore, in step S2, the method for determining the cross-sectional shapes of different types of micro-rib structures is as follows:

[0037] The shape of a rectangular cross section can be uniquely determined after the rib width and depth are determined;

[0038] For V-shaped or trapezoidal cross-sectional shapes, it is necessary to determine the side wall angle γ, that is, the angle between the two sides of the top angle of the V-shape and the angle between the side and the bottom of the trapezoid;

[0039] When the rib width and depth of the V-shaped section are known, the side wall angle γ can be uniquely determined. In addition, the length of the hypotenuse l must be determined to satisfy the following formula:

[0040]

[0041] After the rib width and depth of the isosceles trapezoidal section are known, the side wall angle γ is determined, 90<γ<180, and the upper base a and waist length l are determined accordingly, satisfying the following formula:

[0042]

[0043] a=w-2lsin(γ-90);

[0044] When the rib width and depth of the arc section are known, the curvature radius r can be calculated to satisfy the following formula:

[0045]

[0046] The deflection V-shaped section is based on the rectangular section. A two-dimensional rectangular coordinate system is established with a vertex of the rectangle as the origin. Based on w and d determined by the incoming flow conditions, the deflection V-shaped vertex moves on one side of the rectangular section. The side length is w, the coordinates are (x0, d), and x0≠0.5w. When x0=0.5w, it is a symmetrical V shape. The coordinates of the other two vertices are (0, 0) and (w, 0), respectively. Based on this, the slopes k1 and k2 of the two sides and the side wall angle γ are obtained, which satisfy the following formula:

[0047]

[0048] Where x0 is the horizontal coordinate of the vertex of the deflection V-shape, that is, the length of the vertex from the vertical axis.

[0049] On the basis of the circular arc cross section, the cross section shape can also be an irregular curved edge shape composed of multiple adjustable spline curves. The curve modeling methods include natural cubic spline curves, quadratic and cubic Bezier curves. The specific parameter equations are as follows:

[0050] L i (x) = a i (xx i ) 3 +b i (xx i ) 2 +c i (xx i )+d i ;

[0051] G(t)=(1-t) 2 G0+2(1-t)tG1+t 2 G2;

[0052] H(t)=(1-t) 3 G0+3(1-t) 2 tG1+3(1-t)t 2 G2+t 2 G3;

[0053] Where, L i(x) is the governing equation of the natural cubic spline curve, x is the horizontal coordinate (independent variable) of any point on the spline curve, and x i is the horizontal coordinate of the data point, which is the control point of the spline curve. G(t) is the control equation of the quadratic Bezier curve, H(t) is the control equation of the cubic Bezier curve, and a i , b i 、c i ,d i is the coefficient, G0, G1, G2, G3 are the control points, and t is the parameter, and its value range is [0,1].

[0054] Furthermore, in step S3, when the micro-rib structure on the non-smooth drag reduction rib surface is arranged on a plane cascade plate, a casing or a hub, the arrangement is in the same lateral direction as the blade ribs, or in a flow direction close to the airflow direction.

[0055] Compared with the prior art, the present invention has the following advantages:

[0056] 1. The structural design of the high-load compressor flat blade / annular blade for reducing drag and increasing efficiency provided by the present invention can control various resistances in the blade channel by adding a non-smooth drag-reducing rib surface composed of an array of rib structures on the surfaces of the blades, gratings, casings, and hubs, thereby reducing the separation and vortex losses caused by increased resistance, the mixing losses of the mainstream and the return flow, and the friction losses between the airflow and the blade wall, thereby further improving the performance of the compressor.

[0057] 2. The non-smooth drag reduction rib surface design provided by the present invention can control various resistances in the blade channel without adding auxiliary devices, thereby achieving regulation of boundary layer separation and vortex caused by resistance, and can also adjust the type of friction between the airflow and the blade wall to a certain extent. By changing the structural mode of the bionic ribs on the basis of the existing blade shape, the difficulty of redesigning a new blade is reduced.

[0058] 3. The bionic rib structure design provided by the present invention slightly reduces or substantially maintains the mass of the cascade blades by changing the local structure, and has the advantages of simple structure and good adaptability to working conditions.

[0059] Based on the above reasons, the present invention can be widely promoted in the fields of drag reduction and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0061] Figure 1 Schematic diagram of the high-load diffuser blade structure with non-smooth drag reduction surface blades and gratings in Example 1 of the present invention.

[0062] Figure 2 Schematic diagram of the high-load diffuser blade structure with non-smooth drag reduction surface blades in Example 1 of the present invention.

[0063] Figure 3 Schematic diagram of the high-load diffuser blade structure with a non-smooth drag reduction surface grid plate in Example 1 of the present invention.

[0064] Figure 4 Schematic diagram of the high-load diffuser blade structure with a flow-directed non-smooth drag reduction surface grid plate in Example 1 of the present invention.

[0065] Figure 5 Schematic diagram of the two-dimensional blade profile of a high-load diffuser blade cascade with a non-smooth drag reduction surface in Example 1 of the present invention.

[0066] Figure 6 It is a schematic diagram of the position and parameters of the non-smooth drag reduction surface relative to the blade profile of the present invention.

[0067] Figure 7 It is a schematic diagram of the structure and parameters of the non-smooth drag reduction surface of the present invention.

[0068] Figure 8 Schematic diagram of the annular cascade structure with blades having non-smooth drag reduction surfaces in Example 2 of the present invention.

[0069] Fig. 9 Schematic diagram of the structure of a high-load annular cascade blade with a non-smooth drag reduction surface in Example 2 of the present invention.

[0070] Fig.10 Schematic diagram of the high-load annular blade grid structure with non-smooth drag reduction surface blades and hubs (transverse ribs) in Example 2 of the present invention.

[0071] Fig.11 Schematic diagram of the high-load annular blade grid structure with non-smooth drag reduction surface blades and hubs (flow ribs) in Example 2 of the present invention.

[0072] In the figure: 1. plane blade cascade plate; 2. blade; 3. non-smooth drag reduction rib surface; 4. casing; 5. hub; 6. suction surface; 7. blade non-smooth drag reduction rib surface flow to the starting position; 8. blade non-smooth drag reduction rib surface flow to the end position. DETAILED DESCRIPTION

[0073] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0074] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the 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. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0075] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0076] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0077] Example 1

[0078] The present invention provides a high-load expansion blade structure with a local non-smooth drag reduction rib surface, that is, a compressor plane blade structure with a non-smooth drag reduction rib surface, comprising a plane blade plate 1, a blade 2, and a non-smooth drag reduction rib surface 3. The non-smooth drag reduction rib surface 3 can be arranged on the blade 2 alone (such as Figure 2 As shown), it can also be arranged separately on the plane cascade plate 1 (as shown Figure 3 As shown), it can also be arranged on the blade 2 and the plane cascade plate 1 at the same time (as shown Figure 1 There are three combinations, and the non-smooth drag reduction rib surface 3 is partially present on the blade 2 and / or the plane cascade plate 1. The blade 2 is fixed to the plane cascade plate 1 through the blade grooves provided on the plane cascade plate 1.

[0079] The specific structural form of the non-smooth drag reduction rib surface 3 on the blade 2 is mainly composed of a transverse micro-rib structure array arrangement at an angle of 90° to the flow direction, that is, the micro-rib structure is arranged parallel to the blade height direction. The specific structural form of the non-smooth drag reduction rib surface 3 on the grid plate 1 can be composed of a transverse micro-rib structure array arrangement at an angle of 90° to the flow direction, or it can be composed of a micro-rib structure array arrangement approximate to the flow direction. The cross-sectional shapes of the micro-rib structure mainly include: relatively regular shapes such as rectangles, isosceles trapezoids, V-shaped, arc-shaped, and partially irregular cross-sectional shapes such as angled V-shaped, high-order curves, and other asymmetric shapes. The main parameters involved in the arrangement position of the non-smooth drag reduction rib surface 3 on the surface of the blade 2 include flow parameters and span parameters. The rib structure parameters contained in the non-smooth drag reduction rib surface 3 mainly include rib width, width-to-depth ratio (or width-to-height ratio), spacing (or consistency), etc.

[0080] The design method or steps of the non-smooth drag reduction rib surface 3 are as follows:

[0081] 1. First, determine the incoming flow conditions according to the selected compressor or cascade working conditions, including the incoming flow Mach number and Reynolds number. According to the dimensionless width w of the rib + , dimensionless height d + The actual size of the ribs is determined by combining the definitions (1) and (2) with the incoming flow conditions.

[0082]

[0083] In the formula, μ τ is the wall shear velocity, w is the actual width, d is the actual height, and v is the kinematic viscosity.

[0084] Wall shear velocity μ τ The calculation formula is as follows:

[0085]

[0086] In the formula, is the shear stress near the wall, and ρ is the density.

[0087] Near-wall shear stress It is obtained by the following formula:

[0088]

[0089] Where V ∞ is the incoming flow velocity, and σ is the shear stress near the wall.

[0090] The near-wall shear stress σ is obtained by the following formula:

[0091] σ=0.37×(Re b ) 0.2 (5)

[0092] In the formula, Re b is the Reynolds number, and b is the characteristic length (i.e. the chord length of the blade).

[0093] Reynolds number b It is obtained by the following formula:

[0094]

[0095] Finally, the calculation formulas for rib width and depth are derived as follows:

[0096]

[0097] The actual size of the specific rib, width w and height (or depth) d, obtained according to the above formula, can be combined with the selection of an appropriate cross-sectional shape to determine the structural form of the rib. For the V-shaped or trapezoidal cross-sectional shape, it is also necessary to determine the side wall angle γ, that is, the angle between the two sides of the V-shaped top angle and the angle between the side and bottom of the trapezoid. Different cross-sectional shapes can be selected according to the actual flow control effect, and then the side wall angle γ and the rib width and height and other dimensions can be adjusted to obtain the optimal bionic rib structural parameters for flow control.

[0098] 2. Secondly, determine the specific cross-sectional shape of the ribs based on the basic dimensions of the rib width and depth obtained in the previous step. The methods for determining the cross-sectional shapes of different types of ribs are as follows:

[0099] 1. The shape of a rectangular section can be uniquely determined after the rib width and depth are determined.

[0100] 2. The side wall angle γ of the V-shaped section can be uniquely determined after the rib width and depth are known. In addition, the length of the hypotenuse l must also be determined. The specific formula is as follows:

[0101]

[0102] 3. After the rib width and depth of the isosceles trapezoidal cross section are known, the side wall angle γ (90<γ<180) must be determined, and then the upper base a and waist length l are determined based on this. The specific formula is as follows:

[0103]

[0104] a=w-2lsin(γ-90) (11)

[0105] For isosceles trapezoidal cross-sections, the side wall angle γ needs to be determined based on specific numerical calculation results.

[0106] 4. The radius of curvature r of the arc section can be further calculated based on the known rib width and depth. The specific formula is as follows:

[0107]

[0108] 5. On the basis of the rectangular cross-section, a two-dimensional rectangular coordinate system is established with a vertex of the rectangle as the origin. Based on w and d determined by the incoming flow conditions, the vertex of the angled V-shaped section moves on one side of the rectangular cross-section (side length is w), and its coordinates are (x0, d), and x0≠0.5w (when x0=0.5w, it is a symmetrical V-shape), and the coordinates of the other two vertices are (0, 0) and (w, 0), respectively. Based on this, the slopes k1 and k2 on both sides can be calculated using the following formula, and the side wall angle γ can be further calculated.

[0109]

[0110] Where x0 is the horizontal coordinate of the vertex of the deflection V-shape, that is, the length of the vertex from the vertical axis.

[0111] 6. On the basis of the arc-shaped cross section, the cross-sectional shape can also be an irregular curved edge shape composed of multiple adjustable spline curves. The curve modeling method can include natural cubic spline curves, quadratic and cubic Bezier curves. The specific parameter equations are as follows:

[0112] L i (x) = a i (xx i ) 3 +b i (xx i ) 2 +c i (xx i )+d i (16)

[0113] G(t)=(1-t) 2 G0+2(1-t)tG1+t 2 G2 (17)

[0114] H(t)=(1-t) 3 G0+3(1-t) 2 tG1+3(1-t)t 2 G2+t 2 G3 (18)

[0115] Where, L i (x) is the governing equation of the natural cubic spline curve, x is the horizontal coordinate (independent variable) of any point on the spline curve, and x i is the horizontal coordinate of the data point, which is the control point of the spline curve. G(t) is the control equation of the quadratic Bezier curve, H(t) is the control equation of the cubic Bezier curve, and a i , b i 、c i ,d i is the coefficient, G0, G1, G2, G3 are the control points, and t is the parameter, and its value range is [0,1].

[0116] For the natural cubic spline curve, the coefficient a of each segment is i , b i , c i and d i It is determined by solving a system of linear equations, satisfying the continuity conditions and boundary conditions of the curve.

[0117] 3. After the cross-sectional shape of the ribs is determined, numerical calculations are required to determine the spacing (or consistency) and coverage range and combine with the corresponding position parameters, and then finally determine the arrangement of the ribs on the blades, which are combined into the profile of the non-smooth drag reduction rib surface through array arrangement. Then, the mapping software is used to combine the original blade profile to generate a new blade profile with a non-smooth drag reduction rib surface profile, and further the corresponding blade with a non-smooth drag reduction rib surface is generated through 3D mapping software, and the corresponding grid plate structure can be obtained by combining parameters such as blade profile installation angle and pitch.

[0118] Similarly, the rib structure of the non-smooth drag reduction rib surface can be arranged on the grid plate (i.e., the end wall) in a certain form, and the arrangement can be the same horizontal direction as the blade ribs, or the flow direction close to the airflow direction. The transverse ribs on the non-smooth drag reduction rib surface on the end wall are stretched or swept along the pitch direction by a corresponding length using the above-mentioned rib parameters, and the specific length needs to be determined according to the corresponding numerical calculation results; and the flow direction ribs on the non-smooth drag reduction rib surface are stretched or swept along the suction surface blade profile line from different flow direction positions using the above-mentioned rib parameters. Different flow direction ranges (i.e., the flow direction coverage range of the ribs) are determined according to the numerical calculation results. The design method or determination method of the parameters, cross-sectional shape and structure of the grid plate ribs is consistent with the above method.

[0119] The designed non-smooth drag reduction rib surface structure can be based on the groove form of the blade and end wall surface, or it can be based on the convex form of the blade and end wall surface. Based on the above description, the plane blade with non-smooth drag reduction rib surface can have the following structural forms: ① The non-smooth drag reduction rib surface is arranged on the blade surface alone; ② The non-smooth drag reduction rib surface is arranged on the end wall alone; ③ The non-smooth drag reduction rib surface is arranged on the blade surface and the end wall at the same time. That is, it corresponds to several different blade and grid plate combination schemes: ① The blade with non-smooth drag reduction rib surface is combined with the prototype (smooth) grid plate; ② The prototype (smooth) blade is combined with the grid plate with non-smooth drag reduction rib surface; ③ The blade with non-smooth drag reduction rib surface is combined with the grid plate. Among them, all non-smooth drag reduction rib surface structures include groove type and convex type, and the arrangement of the grid plate (or end wall) ribs has two forms: flow direction and transverse direction.

[0120] For example, the rib structure can be selected to have a trapezoidal cross section. As shown in the figure, w is the rib width and d is the rib depth. The rib shape can be controlled by changing the rib width, rib depth and side wall angle.

[0121] The structural design of the high-load annular cascade blade for reducing drag and increasing efficiency provided by the present invention can control various resistances in the stator channel by adding a non-smooth drag-reducing rib surface composed of a rib array arrangement on the blade surface, thereby reducing the separation and vortex losses, mainstream and backflow mixing losses, and friction losses between the airflow and the blade wall caused by the increase in resistance, thereby further improving the performance of the compressor.

[0122] The non-smooth drag reduction rib surface design provided by the present invention can control various resistances in the blade channel without adding auxiliary devices, thereby realizing the regulation of boundary layer separation and vortex caused by resistance, and can also adjust the type of friction between the airflow and the blade wall to a certain extent. By changing the structural mode of the bionic ribs on the basis of the existing blade shape, the difficulty of redesigning a new blade is reduced.

[0123] The bionic rib structure design provided by the present invention can slightly reduce or substantially keep the mass of the annular cascade blades unchanged by changing the local structure, and has the advantages of simple structure and good adaptability to working conditions.

[0124] Example 2

[0125] Today, as energy crisis and environmental protection issues become increasingly prominent, drag reduction and efficiency improvement have always been the goals pursued in the field of fluid machinery and fluid mechanics. The resistance inside the compressor mainly comes from the friction resistance generated by the contact between the airflow and the wall and the pressure difference resistance induced by the expansion effect and airflow separation. Due to the high complexity and strong unsteadiness of the flow conditions inside the compressor, its friction resistance includes viscous friction resistance and Reynolds stress. The existing flow drag reduction methods are mainly divided into two types: active and passive. There are mainly active drag reduction measures such as wall vibration drag reduction method, bionic jet drag reduction method, fluid displacement method and suction method, as well as passive drag reduction methods such as bionic non-smooth surface drag reduction method, hydrophobic surface drag reduction method, polymer drag reduction method and compliant wall drag reduction method. For high-precision, high-difficulty design and harsh working conditions of mechanical equipment such as compressors, active control methods often add additional adjustment mechanisms and power sources, which not only increase operating consumption and structural complexity, but also increase the difficulty and cost of compressor design. Therefore, as one of the passive control means, the non-smooth surface drag reduction method has shown great application potential in the compressor field. This method has the advantages of simple structure, low design cost and easy implementation. It can achieve drag reduction and efficiency improvement inside the compressor by only changing the wall microstructure of the compressor blades and grooves. On the one hand, it can effectively control or weaken the channel vortex loss near the corner separation area and the mixing loss caused by it, and at the same time, it also reduces the various resistances and related losses generated in the blade channel accordingly, while keeping the blade mass slightly changed.

[0126] The reduction of resistance in the field of fluid machinery is crucial to reducing energy consumption and improving performance. The performance requirements of the next generation of advanced gas turbines will further increase the load of the multi-stage axial flow compressor inside. Under the premise of limited number of stages and minimizing weight increase, the increase in stage load makes the single-stage pressure ratio of the compressor higher and the blade aspect ratio smaller. The increase in stage pressure ratio further increases the flow reverse pressure gradient and lateral pressure gradient in the blade channel, while the reduction in blade aspect ratio makes the end wall boundary layer thicker. The thickened boundary layer is more likely to undergo boundary layer separation under higher pressure gradients. The separation causes the Reynolds stress and pressure difference resistance of the airflow to increase sharply, and at the same time, various concentrated vortex systems will be generated to cause a strong airflow mixing effect, resulting in a large mixing loss. At the same time, the low-energy fluid blocking the flow channel caused by separation further causes compressor blockage, reduced efficiency, etc. In severe cases, it may even cause the compressor to stall and surge, posing a serious threat to the safe and stable operation of the compressor. Therefore, taking effective measures to reduce the various resistances caused by turbulence or separation inside the compressor and weakening the flow separation in the compressor and the related losses it produces are of great significance to further improve the performance of the compressor and even the gas turbine.

[0127] The present invention provides an annular blade grid structure with a locally non-smooth drag reduction rib surface. The annular blade grid structure (stator structure) with bionic ribs is obtained by adjusting the structural form and arrangement position of the bionic ribs, thereby weakening the angular separation strength in the annular blade grid channel (stator channel), reducing the vortex loss, mixing loss and friction loss between the airflow and the blade surface caused by separation, thereby improving the pressure diffusion capacity of the annular blade grid (stator), and ultimately improving the performance of the compressor.

[0128] The structure of the present invention is as follows Figure 8 The schematic diagram of the annular blade grid structure with a non-smooth drag reduction rib surface is shown, which includes blades 2 (high-load annular blade grid blades, stator blades), non-smooth drag reduction rib surfaces 3, casing 4, hub 5, and suction surface 6. Among them, the non-smooth drag reduction rib surface 3 can be arranged alone on the blade 2, or on the casing 4 or the hub 5, or on the blade 2 and the casing 4 at the same time, or on the blade 2 and the hub 5 at the same time, or on the casing 4 and the hub 5 at the same time, or on the blade 2, the casing 4, and the hub 5 at the same time, that is, there are seven combinations, and the arrangement position of the non-smooth drag reduction rib surface 3 is determined according to the specific flow conditions in the annular blade grid. And this kind of non-smooth drag reduction rib surface 3 is locally present on the blade 2, the casing 4, and the hub 5. As Fig. 9 As shown, the two side edges of the non-smooth drag reduction rib surface 3 are respectively the flow starting position 7 of the blade non-smooth drag reduction rib surface and the flow ending position 8 of the blade non-smooth drag reduction rib surface.

[0129] The specific structural form of the non-smooth drag reduction rib surface 3 on the blade 2 is mainly composed of a transverse micro-rib structure array arrangement at an angle of 90° to the flow direction, that is, the micro-rib structure is arranged parallel to the height direction of the blade 2. The specific structural form of the non-smooth drag reduction rib surface 3 on the casing 4 and the hub 5 can be composed of a transverse micro-rib structure array arrangement at an angle of 90° to the flow direction, or it can be composed of a micro-rib structure array arrangement approximate to the flow direction. The cross-sectional shapes of the micro-rib structure mainly include: relatively regular shapes such as rectangles, isosceles trapezoids, V-shaped, arc-shaped, and partially irregular cross-sectional shapes such as angled V-shaped, high-order curves, and other asymmetric shapes. The main parameters involved in the arrangement position of the non-smooth drag reduction rib surface 3 on the surface of the blade 2 include flow parameters and span parameters. The rib structure parameters contained in the non-smooth drag reduction rib surface 3 mainly include rib width, width-to-depth ratio (or width-to-height ratio), spacing (or consistency), etc.

[0130] The design method or steps of the non-smooth drag reduction rib surface 3 are as follows:

[0131] 1. First, determine the incoming flow conditions according to the selected compressor or cascade working conditions, including the incoming flow Mach number and Reynolds number. According to the dimensionless width w of the rib + , dimensionless height d+ The actual size of the ribs is determined by combining the definitions (1) and (2) with the incoming flow conditions.

[0132]

[0133] In the formula, μ τ is the wall shear velocity, w is the actual width, d is the actual height, and v is the kinematic viscosity.

[0134] Wall shear velocity μ τ The calculation formula is as follows:

[0135]

[0136] In the formula, is the shear stress near the wall, and ρ is the density.

[0137] Near-wall shear stress It is obtained by the following formula:

[0138]

[0139] Where V ∞ is the incoming flow velocity, and σ is the shear stress near the wall.

[0140] The near-wall shear stress σ is obtained by the following formula:

[0141] σ=0.37×(Re b ) 0.2 (5)

[0142] In the formula, Re b is the Reynolds number, and b is the characteristic length (i.e. the chord length of the blade).

[0143] Reynolds number b It is obtained by the following formula:

[0144]

[0145] Finally, the calculation formulas for rib width and depth are derived as follows:

[0146]

[0147] The actual size of the specific rib, width w and height (or depth) d, obtained according to the above formula, can be combined with the selection of an appropriate cross-sectional shape to determine the structural form of the rib. For the V-shaped or trapezoidal cross-sectional shape, it is also necessary to determine the side wall angle γ, that is, the angle between the two sides of the V-shaped top angle and the angle between the side and bottom of the trapezoid. Different cross-sectional shapes can be selected according to the actual flow control effect, and then the side wall angle γ and the rib width and height and other dimensions can be adjusted to obtain the optimal bionic rib structural parameters for flow control.

[0148] 2. Secondly, determine the specific cross-sectional shape of the ribs based on the basic dimensions of the rib width and depth obtained in the previous step. The methods for determining the cross-sectional shapes of different types of ribs are as follows:

[0149] 1. The shape of a rectangular section can be uniquely determined after the rib width and depth are determined.

[0150] 2. The side wall angle γ of the V-shaped section can be uniquely determined after the rib width and depth are known. In addition, the length of the hypotenuse l must also be determined. The specific formula is as follows:

[0151]

[0152] 3. After the rib width and depth of the isosceles trapezoidal cross section are known, the side wall angle γ (90<γ<180) must be determined, and then the upper base a and waist length l are determined based on this. The specific formula is as follows:

[0153]

[0154] a=w-2lsin(γ-90) (11)

[0155] For isosceles trapezoidal cross-sections, the side wall angle γ needs to be determined based on specific numerical calculation results.

[0156] 4. The radius of curvature r of the arc section can be further calculated based on the known rib width and depth. The specific formula is as follows:

[0157]

[0158] 5. On the basis of the rectangular cross-section, a two-dimensional rectangular coordinate system is established with a vertex of the rectangle as the origin. Based on w and d determined by the incoming flow conditions, the vertex of the angled V-shaped section moves on one side of the rectangular cross-section (side length is w), and its coordinates are (x0, d), and x0≠0.5w (when x0=0.5w, it is a symmetrical V-shape), and the coordinates of the other two vertices are (0, 0) and (w, 0), respectively. Based on this, the slopes k1 and k2 on both sides can be calculated using the following formula, and the side wall angle γ can be further calculated.

[0159]

[0160] Where x0 is the horizontal coordinate of the vertex of the deflection V-shape, that is, the length of the vertex from the vertical axis.

[0161] 6. On the basis of the arc-shaped cross section, the cross-sectional shape can also be an irregular curved edge shape composed of multiple adjustable spline curves. The curve modeling method can include natural cubic spline curves, quadratic and cubic Bezier curves. The specific parameter equations are as follows:

[0162] L i (x) = ai (xx i ) 3 +b i (xx i ) 2 +c i (xx i )+d i (16)

[0163] G(t)=(1-t) 2 G0+2(1-t)tG1+t 2 G2 (17)

[0164] H(t)=(1-t) 3 G0+3(1-t) 2 tG1+3(1-t)t 2 G2+t 2 G3 (18)

[0165] Where, L i (x) is the governing equation of the natural cubic spline curve, x is the horizontal coordinate (independent variable) of any point on the spline curve, and x i is the horizontal coordinate of the data point, which is the control point of the spline curve. G(t) is the control equation of the quadratic Bezier curve, H(t) is the control equation of the cubic Bezier curve, and a i , b i 、c i ,d i is the coefficient, G0, G1, G2, G3 are the control points, and t is the parameter, and its value range is [0,1].

[0166] For the natural cubic spline curve, the coefficient a of each segment is i , b i , c i and d i It is determined by solving a system of linear equations, satisfying the continuity conditions and boundary conditions of the curve.

[0167] 3. After the cross-sectional shape of the ribs is determined, numerical calculations are required to determine the spacing (or consistency) and coverage range and combine with the corresponding position parameters, and then finally determine the arrangement of the ribs on the blades, which are combined into the profile of the non-smooth drag-reducing rib surface through array arrangement. Then, the new blade profile with non-smooth drag-reducing rib surface profile is generated by combining the original blade profile with the mapping software, and the corresponding blade with non-smooth drag-reducing rib surface is further generated by the three-dimensional mapping software. The corresponding hub structure can be obtained by combining the parameters such as the blade installation angle and pitch.

[0168] Similarly, the rib structure of the non-smooth drag reduction rib surface can be arranged on the hub (i.e., end wall) or casing in a certain form, and the arrangement can be the same horizontal direction as the blade ribs, or the flow direction close to the airflow direction. The transverse ribs on the non-smooth drag reduction rib surface on the hub or casing are stretched or swept along the pitch direction by a corresponding length using the above-mentioned rib parameters, and the specific length needs to be determined according to the corresponding numerical calculation results; and the flow direction ribs on the non-smooth drag reduction rib surface are stretched or swept along the suction surface blade line by the above-mentioned rib parameters from different flow direction positions (i.e., the flow direction coverage range of the ribs), and the specific data are determined according to the numerical calculation results. The design method or determination method of the parameters, cross-sectional shape and structure of the grid plate ribs is consistent with the above method.

[0169] The designed non-smooth drag reduction rib surface structure can be a groove form based on the surface of the blade and the hub (or casing), or a convex form based on the surface of the blade and the hub (or casing). The annular blade cascade with non-smooth drag reduction rib surface obtained based on the above description can have the following structural forms: ① The non-smooth drag reduction rib surface is arranged alone on the blade surface; ② The non-smooth drag reduction rib surface is arranged alone on the hub or casing; ③ The non-smooth drag reduction rib surface is arranged on the blade surface and the hub (or casing) at the same time; ④ The non-smooth drag reduction rib surface is arranged on the casing and the hub at the same time; ⑤ The non-smooth drag reduction rib surface is arranged on the blade surface, the hub and the casing at the same time. That is, it corresponds to several different blade and hub (or casing) combination schemes: ① non-smooth drag reduction rib surface blade combined with prototype (smooth) hub and casing, ② prototype (smooth) blade combined with non-smooth drag reduction rib surface hub (or casing), ③ non-smooth drag reduction rib surface blade combined with hub (or casing), ④ non-smooth drag reduction rib surface casing and hub combination, ⑤ non-smooth drag reduction rib surface blade, hub and casing combination. Among them, all non-smooth drag reduction rib surface structures include groove type and protrusion type, and the hub (or casing) ribs are arranged in two forms: flow direction and transverse direction.

[0170] For example, the rib structure can be selected to have a trapezoidal cross section. As shown in the figure, w is the rib width and d is the rib depth. The rib shape can be controlled by changing the rib width, rib depth and side wall angle.

[0171] The structural design of the high-load annular cascade blade for reducing drag and increasing efficiency provided by the present invention can control various resistances in the stator channel by adding a non-smooth drag-reducing rib surface composed of a rib array arrangement on the blade surface, thereby reducing the separation and vortex losses, mainstream and backflow mixing losses, and friction losses between the airflow and the blade wall caused by the increase in resistance, thereby further improving the performance of the compressor.

[0172] The non-smooth drag reduction rib surface design provided by the present invention can control various resistances in the blade channel without adding auxiliary devices, thereby realizing the regulation of boundary layer separation and vortex caused by resistance, and can also adjust the type of friction between the airflow and the blade wall to a certain extent. By changing the structural mode of the bionic ribs on the basis of the existing blade shape, the difficulty of redesigning a new blade is reduced.

[0173] The bionic rib structure design provided by the present invention can slightly reduce or substantially keep the mass of the annular cascade blades unchanged by changing the local structure, and has the advantages of simple structure and good adaptability to working conditions.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-load diffuser blade structure with a local non-smooth drag reduction rib surface, characterized in that: The diffuser blade cascade structure is a planar blade cascade structure or an annular blade cascade structure, and a non-smooth drag reduction rib surface (3) is provided on the planar blade cascade structure and the annular blade cascade structure.

2. The high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 1, characterized in that: The planar cascade structure comprises a planar cascade plate (1) and a blade (2), wherein the blade (2) is fixedly connected to the planar cascade plate (1) via a blade profile groove arranged on the planar cascade plate (1), and the non-smooth drag reduction rib surface (3) is arranged alone on the blade (2); or, the non-smooth drag reduction rib surface (3) is arranged alone on the planar cascade plate (1); or, the non-smooth drag reduction rib surface (3) is arranged on both the blade (2) and the planar cascade plate (1); The non-smooth drag reduction rib surface (3) exists locally on the blade (2) and / or the plane cascade plate (1).

3. The high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 1, characterized in that: The annular blade cascade structure comprises a casing (4), a hub (5) and a blade (2); the non-smooth drag reduction rib surface (3) is arranged alone on the blade (2); or the non-smooth drag reduction rib surface (3) is arranged alone on the casing (4) or the hub (5); or the non-smooth drag reduction rib surface (3) is arranged on both the blade (2) and the casing (4); or the non-smooth drag reduction rib surface (3) is arranged on both the blade (2) and the hub (5); or the non-smooth drag reduction rib surface (3) is arranged on both the casing (4) and the hub (5); or the non-smooth drag reduction rib surface (3) is arranged on both the casing (4) and the hub (5); or the non-smooth drag reduction rib surface (3) is arranged on the blade (2), the casing (4) and the hub (5); The non-smooth drag reduction rib surface (3) exists locally on the blade (2), the casing (4) or the hub (5); or, the non-smooth drag reduction rib surface (3) exists locally on the blade (2) and the casing (4); the non-smooth drag reduction rib surface (3) exists locally on the blade (2) and the hub (5); or, the non-smooth drag reduction rib surface (3) exists locally on the casing (4) and the hub (5); or, the non-smooth drag reduction rib surface (3) exists locally on the blade (2), the casing (4) and the hub (5).

4. The high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 2, characterized in that: The non-smooth drag reduction rib surface (3) on the blade (2) is a structure composed of a transverse micro-rib structure array arranged at an angle of 90 degrees to the flow direction, and the non-smooth drag reduction rib surface (3) on the plane cascade plate (1) is a structure composed of a transverse or flow direction micro-rib structure array arranged.

5. The high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 3, characterized in that: The non-smooth drag reduction rib surface (3) on the blade (2) is a structure composed of a transverse micro-rib structure array arranged at an angle of 90 degrees to the flow direction, and the non-smooth drag reduction rib surface (3) on the casing (4) and the hub (5) is a structure composed of a transverse or flow direction micro-rib structure array arranged.

6. The high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 1, 4 or 5, characterized in that: The cross-sectional shape of the micro-rib structure is a regular shape, a partially irregular shape or an asymmetric shape, the regular shape at least includes a rectangle, an isosceles trapezoid, a V shape, and an arc shape, the partially irregular shape at least includes an angled V shape, and the asymmetric shape at least includes a high-order curve shape; The micro-rib structure is in the form of a groove structure or a protrusion structure.

7. A design method for a high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to any one of claims 1 to 6, characterized in that: The steps include: S1. Determine the incoming flow conditions according to the selected compressor or cascade working conditions, and the dimensionless width w of the micro-rib structure + , dimensionless height d + , the actual size of the micro-rib structure is determined in combination with the incoming flow conditions, and the width and depth of the micro-rib structure are obtained; S2, determining the cross-sectional shape of the micro-rib structure according to the width and depth of the micro-rib structure obtained in step S1; S3. After the cross-sectional shape of the micro-rib structure is determined, numerical calculation is performed to determine the spacing and coverage range, and combined with the corresponding position parameters, the arrangement form of the micro-rib structure on the plane blade grid structure or the annular blade grid structure is finally determined, and the array arrangement is combined into the profile of the non-smooth drag reduction rib surface (3); then, a new blade profile with a non-smooth drag reduction rib surface (3) profile is generated by combining the original blade profile with a drawing software, and a corresponding blade profile with a non-smooth drag reduction rib surface (3) is generated by a three-dimensional drawing software, and the corresponding high-load expansion blade structure is obtained by combining the blade profile installation angle and pitch parameters.

8. The design method of a high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 7, characterized in that: In step S1, the incoming flow conditions at least include the incoming flow Mach number and Reynolds number; Dimensionless width w + , dimensionless height d + Satisfies the following formula: In the formula, μ τ is the wall shear velocity, w is the actual width, d is the actual height, and v is the kinematic viscosity; Wall shear velocity μ τ Satisfies the following formula: In the formula, is the near-wall shear stress, ρ is the density; Near-wall shear stress Satisfies the following formula: Where V ∞ is the incoming flow velocity, σ is the shear stress near the wall; The near-wall shear stress σ satisfies the following formula: σ=0.37×(Re b ) 0.2 ; In the formula, Re b is the Reynolds number, b is the characteristic length, i.e. the blade chord length; Reynolds number b Satisfies the following formula: The width and depth of the final micro-rib structure satisfy the following formula:

9. The design method of a high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 7, characterized in that: In step S2, the method for determining the cross-sectional shapes of different types of micro-rib structures is as follows: The shape of a rectangular cross section can be uniquely determined after the rib width and depth are determined; For V-shaped or trapezoidal cross-sectional shapes, it is necessary to determine the side wall angle γ, that is, the angle between the two sides of the top angle of the V-shape and the angle between the side and the bottom of the trapezoid; When the rib width and depth of the V-shaped section are known, the side wall angle γ can be uniquely determined. In addition, the length of the hypotenuse l must be determined to satisfy the following formula: After the rib width and depth of the isosceles trapezoidal section are known, the side wall angle γ is determined, 90<γ<180, and the upper base a and waist length l are determined accordingly, satisfying the following formula: a=w-2lsin(γ-90); When the rib width and depth of the arc section are known, the curvature radius r can be calculated to satisfy the following formula: The deflection V-shaped section is based on the rectangular section. A two-dimensional rectangular coordinate system is established with a vertex of the rectangle as the origin. Based on w and d determined by the incoming flow conditions, the deflection V-shaped vertex moves on one side of the rectangular section. The side length is w, the coordinates are (x0, d), and x0≠0.5w. When x0=0.5w, it is a symmetrical V shape. The coordinates of the other two vertices are (0, 0) and (w, 0), respectively. Based on this, the slopes k1 and k2 of the two sides and the side wall angle γ are obtained, which satisfy the following formula: Where x0 is the horizontal coordinate of the vertex of the deflection V-shape, that is, the length of the vertex from the vertical axis. On the basis of the circular arc cross section, the cross section shape can also be an irregular curved edge shape composed of multiple adjustable spline curves. The curve modeling methods include natural cubic spline curves, quadratic and cubic Bezier curves. The specific parameter equations are as follows: L i (x)=a i (x-x i ) 3 +b i (x-x i ) 2 +c i (x-x i )+d i ; G(t)=(1-t) 2 G0+2(1-t)tG1+t 2 G2; H(t)=(1-t) 3 G0+3(1-t) 2 tG1+3(1-t)t 2 G2+t 2 G3; Where, L i (x) is the governing equation of the natural cubic spline curve, x is the horizontal coordinate (independent variable) of any point on the spline curve, and x i is the horizontal coordinate of the data point, which is the control point of the spline curve. G(t) is the control equation of the quadratic Bezier curve, H(t) is the control equation of the cubic Bezier curve, and a i 、b i 、c i d i is the coefficient, G0, G1, G2, G3 are the control points, and t is the parameter, and its value range is [0,1].

10. The design method of a high-load diffuser blade structure with a local non-smooth drag reduction rib surface according to claim 7, characterized in that: In the step S3, when the micro-rib structure of the non-smooth drag reduction rib surface (3) is arranged on the plane cascade plate (1), the casing (4) or the hub (5), the arrangement is in the same lateral direction as the ribs of the blade (2), or in a flow direction close to the airflow direction.

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