Method and device for optimizing blade placement angle of high-speed and high-efficiency axial flow pump

Abstract

The present invention discloses a method and device for optimizing the blade placement angle of a high-speed, high-efficiency axial flow pump, including: step S1, determining the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and the number of blades of the high-speed axial flow pump; step S2, dividing the blades into sections with equal spacing from the impeller rim to the hub; step S3, designing the inlet placement angles of blades with different sections by the free vortex method, and designing the outlet placement angles of blades by the forced vortex method; step S4, thickening the blades by the 791 airfoil thickening method. The technical solution of the present invention is adopted to improve the head and efficiency of the high-speed axial flow pump, and at the same time, the anti-cavitation performance is also improved, and the pump has the characteristics of high efficiency, energy saving, environmental protection and stable operation.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid machinery, and in particular relates to a method and device for optimizing the design of blade placement angles of a high-speed and high-efficiency axial flow pump. Background Art

[0002] Axial flow pumps have the characteristics of large flow and low head, with a specific speed of 500-1600. They are widely used in fields with large flow water supply needs, such as farmland irrigation, flood drainage, urban water supply, and ship water jet propulsion. At present, combined with the existing excellent hydraulic design models and engineering experience of axial flow pumps, many scholars have proposed blade optimization design methods for blade outlet axial surface velocity, circulation distribution, and thickness distribution, aiming at the shortcomings of low efficiency and narrow high-efficiency zone of axial flow pumps with a speed less than 2000r / min. However, there are few studies on the optimization and improvement of the efficiency and anti-cavitation performance of axial flow pumps with a speed greater than 3000r / min. The increase in speed causes the axial flow pump to have low efficiency and poor anti-cavitation performance. Forced vortex and free vortex are often used to design the blade placement angle. Among them, the blade placement angle designed by the forced vortex method can improve the blade anti-cavitation performance, but there are certain limitations on the improvement of the efficiency of the axial flow pump. The axial flow pump designed by the free vortex method has a higher efficiency, but the anti-cavitation performance deteriorates and increases the dependence on the downstream guide vanes. On this basis, a blade placement angle design method is proposed to optimize the efficiency and anti-cavitation performance of axial flow pumps with a speed greater than 3000r / min. It can not only improve the anti-cavitation performance of the pump, reduce the vibration and noise of the unit, but also improve the hydraulic efficiency of the axial flow pump, achieving the purpose of energy saving and environmental protection. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method and device for optimizing the design of blade placement angles of a high-speed and high-efficiency axial flow pump.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for optimizing the blade placement angle of a high-speed and high-efficiency axial flow pump, comprising:

[0006] Step S1, determining the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of the high-speed axial flow pump blades;

[0007] Step S2, dividing the blade into sections at equal intervals from the impeller rim to the hub;

[0008] Step S3, the inlet placement angles of blades with different cross sections are designed using the free vortex method, and the outlet placement angles of blades are designed using the forced vortex method.

[0009] Preferably, the blade is divided into sections at equal intervals from the impeller rim to the hub, namely rim (Span=1), Span=0.75, Span=0.5, Span=0.25 and hub (Span=0).

[0010] As a preferred embodiment, the variation rule of the blade inlet placement angle along the blade span direction is expressed as follows:

[0011] Span=1(rim) inlet placement angle:

[0012] Span=0.75Inlet placement angle:

[0013] Span=0.5Inlet placement angle:

[0014] Span=0.25Inlet placement angle:

[0015] Span=0(wheel hub) inlet placement angle:

[0016] Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter of the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, and γ is the inlet angle of attack.

[0017] As a preferred embodiment, the variation law of the blade outlet placement angle along the blade span direction is expressed as follows:

[0018] Span=1(rim) outlet placement angle:

[0019] Span=0.75Export placement angle:

[0020] Span=0.5Export placement angle:

[0021] Span=0.25Export placement angle:

[0022] Span=0(hub) outlet placement angle:

[0023] Among them, β2 is the outlet effective diameter placement angle, β2=β′2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

[0024] Preferably, the method further includes: step S4, thickening the blade using the 791 airfoil thickening method.

[0025] The present invention also provides a blade placement angle optimization design device for a high-speed and high-efficiency axial flow pump, comprising:

[0026] A determination module, used to determine the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of a high-speed axial flow pump blade;

[0027] A dividing module is used to divide the blade into sections at equal intervals from the impeller rim to the hub;

[0028] The design module is used to design the inlet placement angle of blades with different sections using the free vortex method, and the outlet placement angle of blades using the forced vortex method.

[0029] Preferably, the dividing module divides the blade into sections at equal intervals from the impeller rim to the hub, namely rim (Span=1), Span=0.75, Span=0.5, Span=0.25 and hub (Span=0).

[0030] As a preferred embodiment, the variation law of the blade inlet placement angle along the blade span direction is expressed as follows:

[0031] Span=1(rim) inlet placement angle:

[0032] Span=0.75Inlet placement angle:

[0033] Span=0.5Inlet placement angle:

[0034] Span=0.25Inlet placement angle:

[0035] Span=0(wheel hub) inlet placement angle:

[0036] Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter of the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, and γ is the inlet angle of attack.

[0037] As a preferred embodiment, the variation law of the blade outlet placement angle along the blade span direction is expressed as follows:

[0038] Span=1(rim) outlet placement angle:

[0039] Span=0.75Export placement angle:

[0040] Span=0.5Export placement angle:

[0041] Span=0.25Export placement angle:

[0042] Span=0(hub) outlet placement angle:

[0043] Among them, β2 is the outlet effective diameter placement angle, β2=β′2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

[0044] As a preference, it also includes: a thickening module for thickening the blade using the 791 airfoil thickening method

[0045] Firstly, the basic parameters of the axial flow pump blade inlet and outlet diameters and speed are determined according to the given design parameters and pipeline dimensions. Secondly, the blade is divided into sections with equal intervals from the impeller rim to the hub, namely rim (Span=1), Span=0.75, Span=0.5, Span=0.25 and hub (Span=0). On this basis, the inlet placement angles of blades with different sections are designed using the free vortex method, and the outlet placement angles of blades are designed using the forced vortex method. Finally, the blades are thickened using the 791 airfoil thickening method.

[0046] The free vortex and forced vortex mixing design of the present invention and the method of optimizing the blade placement angle improve the head and efficiency of the high-speed axial flow pump, while improving the anti-cavitation performance of the high-speed axial flow pump. It has the characteristics of high efficiency, energy saving, environmental protection and stable operation, and has broad application prospects in the design process of high-efficiency and high-cavitation resistance of axial flow pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] 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 only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0048] Figure 1 A flow chart of the optimized design of blade placement angle of a high-speed and high-efficiency axial flow pump according to an embodiment of the present invention;

[0049] Figure 2 This is a structural diagram of the axial flow pump of the present invention;

[0050] Figure 3 It is a schematic diagram of the thickness variation of the 791 airfoil;

[0051] Figure 4Schematic diagram of the inlet and outlet velocity triangles of different sections under the two design methods of the present invention;

[0052] Figure 5 This is a comparison chart of hydraulic performance under different design methods, where original refers to the forced vortex design method for the inlet installation angle, and optimal refers to the free vortex design method for the inlet installation angle. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Embodiment 1:

[0056] like Figure 1 , 2 As shown, an embodiment of the present invention provides a method for optimizing the blade placement angle of a high-speed and high-efficiency axial flow pump, comprising:

[0057] Step S1, determining the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of a high-speed axial flow pump blade; wherein the axial flow pump comprises: blades 1, guide vanes 2 and hub 3;

[0058] Step S2, dividing the blade into sections at equal intervals from the impeller rim to the hub;

[0059] Step S3, the inlet placement angles of blades with different cross sections are designed using the free vortex method, and the outlet placement angles of blades are designed using the forced vortex method;

[0060] Step S4: thicken the blade using the 791 airfoil thickening method.

[0061] As an implementation mode of the present invention, in step S2, the blade is divided into sections with equal intervals from the impeller rim to the hub, namely rim (Span=1), Span=0.75, Span=0.5, Span=0.25 and hub (Span=0).

[0062] As an implementation mode of the present invention, the variation rule of the blade inlet placement angle along the blade span direction is expressed as follows:

[0063] Span=1(rim) inlet placement angle:

[0064] Span=0.75Inlet placement angle:

[0065] Span=0.5Inlet placement angle:

[0066] Span=0.25Inlet placement angle:

[0067] Span=0(wheel hub) inlet placement angle:

[0068] Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter of the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, and γ is the inlet angle of attack.

[0069] As an implementation mode of the present invention, the variation rule of the blade outlet placement angle along the blade span direction is expressed as follows:

[0070] Span=1(rim) outlet placement angle:

[0071] Span=0.75Export placement angle:

[0072] Span=0.5Export placement angle:

[0073] Span=0.25Export placement angle:

[0074] Span=0(hub) outlet placement angle:

[0075] Among them, β2 is the outlet effective diameter placement angle, β2=β′2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2=(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

[0076] As an implementation mode of the present invention, in step S4, the maximum blade thickness δ max =0.02D t2 According to the 791 airfoil thickness variation rule Table 1 and Figure 2 The thickness variation pattern of the 791 airfoil shown is that the airfoil thickens with the profile line as the working surface and increases towards the back.

[0077] Table 1

[0078] x / l 0 0.05 0.075 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.95 1.0 <![CDATA[δδ max ]]> 0 0.296 0.405 0.489 0.778 0.92 0.978 1.0 0.883 0.756 0.544 0.356 0.2 0

[0079] Embodiment 2:

[0080] The embodiment of the present invention also provides a method for optimizing the blade placement angle of a high-speed and high-efficiency axial flow pump. The design flow rate Q of the axial flow pump in the embodiment of the present invention is 650m 3 / h, head H is 11m, speed n is 3600r / min, specific speed n s It is 924.

[0081] (1) Calculation of basic parameters: impeller rim diameter 200 mm, hub inlet diameter 75 mm, hub outlet diameter 110 mm, inlet axial velocity 7.39 m / s, outlet axial velocity 9.12 m / s, inlet effective diameter circumferential velocity 28.47 m / s, outlet effective diameter circumferential velocity 30.42 m / s, inlet effective diameter absolute velocity circumferential component 0.7 m / s, outlet effective diameter absolute velocity circumferential component 5.51 m / s, number of blades 4;

[0082] (2) Dividing the flow surface: According to the principle of equal spacing from the rim to the hub, the blade is divided into five sections: rim (Span = 1), Span = 0.75, Span = 0.5, Span = 0.25 and hub (Span = 0);

[0083] (3) Calculate the inlet placement angle of blades with different sections:

[0084] Span=1(rim) inlet placement angle:

[0085] Span=0.75Inlet placement angle:

[0086] Span=0.5Inlet placement angle:

[0087] Span=0.25Inlet placement angle:

[0088] Span=0(wheel hub) inlet placement angle:

[0089] Among them, v m1 is the inlet axial speed, m / s; v u1 is the circumferential component of the inlet velocity, m / s; The circumferential velocity of the effective diameter of the inlet at 0.75 Span, m / s; The circumferential velocity of the effective diameter of the inlet at 0.5 Span, m / s; The circumferential velocity of the effective diameter of the inlet at 0.25 Span, m / s; is the effective diameter circumferential velocity at the hub, m / s; γ is the inlet attack angle, which is 2.5°.

[0090] (4) Calculate the outlet angle of blades with different sections:

[0091] Span=1(rim) outlet placement angle:

[0092] Span=0.75Export placement angle:

[0093] Span=0.5Export placement angle:

[0094] Span=0.25Export placement angle:

[0095] Span=0(hub) outlet placement angle:

[0096] Among them, β2 is the outlet effective diameter placement angle. Due to the deviation between the flow angle and the placement angle caused by the flow channel slip, the outlet offset angle is used for empirical correction, where β2 = β′2 + Vβ2, the outlet effective diameter flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, m / s; D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, mm; D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, mm; D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective diameter of the outlet at 0.25Span, mm.

[0097] (5) Thickened blades:

[0098] Maximum blade thickness δ max =0.02D t2 According to the thickness change law of the 791 airfoil, thicken the back side with the profile line as the working surface.

[0099] (6) The blade inlet placement angle adopts two design methods: free swirl and forced swirl. Table 1 shows the comparison of blade placement angles of different design methods. The inlet velocity triangle is shown in Figure 4 shown.

[0100] Table 1

[0101] Import section rim Span = 0.75 Span = 0.5 Span = 0.25 Wheels Free vortex 7.85° 9.98° 11.56° 14.57° 21.19° Forced Vortex 9.11° 10.94° 13.68° 18.18° 26.78° Exit section rim Span = 0.75 Span = 0.5 Span = 0.25 Wheels Forced Vortex 17.91° 20.45° 23.79° 28.32° 34.73°

[0102] (7) Through three-dimensional modeling and simulation calculation, the head and efficiency of the axial flow pump designed by the forced vortex method and the hybrid method are compared. Figure 5 As shown, the efficiency and head of the axial flow pump designed by the design method of the present invention are significantly improved, the torque is reduced, the power is slightly increased, and higher hydraulic performance is shown.

[0103] Embodiment 3:

[0104] The embodiment of the present invention also provides a blade placement angle optimization design device for a high-speed and high-efficiency axial flow pump, comprising:

[0105] A determination module, used to determine the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of a high-speed axial flow pump blade;

[0106] A dividing module is used to divide the blade into sections at equal intervals from the impeller rim to the hub;

[0107] The design module is used to design the inlet placement angle of blades with different sections using the free vortex method, and the outlet placement angle of blades using the forced vortex method.

[0108] As an implementation mode of the present invention, the dividing module divides the blade into sections with equal intervals from the impeller rim to the hub, namely rim (Span=1), Span=0.75, Span=0.5, Span=0.25 and hub (Span=0).

[0109] As an implementation mode of the present invention, the variation rule of the blade inlet placement angle along the blade span direction is expressed as follows:

[0110] Span=1(rim) inlet placement angle:

[0111] Span=0.75Inlet placement angle:

[0112] Span=0.5Inlet placement angle:

[0113] Span=0.25Inlet placement angle:

[0114] Span=0(wheel hub) inlet placement angle:

[0115] Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter of the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, and γ is the inlet angle of attack.

[0116] As an implementation mode of the present invention, the variation rule of the blade outlet placement angle along the blade span direction is expressed as follows:

[0117] Span=1(rim) outlet placement angle:

[0118] Span=0.75Export placement angle:

[0119] Span=0.5Export placement angle:

[0120] Span=0.25Export placement angle:

[0121] Span=0(hub) outlet placement angle:

[0122] Among them, β2 is the outlet effective diameter placement angle, β2=β′2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

[0123] As an implementation mode of the present invention, it also includes: a thickening module, which is used to thicken the blade using the 791 airfoil thickening method.

[0124] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for optimizing the blade placement angle of a high-speed and high-efficiency axial flow pump, characterized in that: include: Step S1, determining the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of the high-speed axial flow pump blades; Step S2, dividing the blade into sections at equal intervals from the impeller rim to the hub; Step S3, the inlet placement angles of blades with different cross sections are designed by the free vortex method, and the outlet placement angles of blades are designed by the forced vortex method; The blade is divided into sections with equal spacing from the impeller rim to the hub, namely rim, Span = 0.75, Span = 0.5, Span = 0.25 and hub, where rim: Span = 1, hub: Span = 0; The variation law of the blade inlet placement angle along the blade span direction is expressed as follows: Span=1Inlet placement angle: Span=0.75Inlet placement angle: Span=0.5Inlet placement angle: Span=0.25Inlet placement angle: Span=0Inlet placement angle: Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter at the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, γ is the inlet attack angle; The variation law of blade outlet placement angle along the blade span direction is expressed as follows: Span=1Export placement angle: Span=0.75Export placement angle: Span=0.5Export placement angle: Span=0.25Export placement angle: Span=0 Exit placement angle: Among them, β2 is the outlet effective diameter placement angle, β2=β'2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72°. is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

2. The blade placement angle optimization design method for a high-speed and high-efficiency axial flow pump according to claim 1 is characterized in that: The method also includes: step S4, thickening the blade using the 791 airfoil thickening method.

3. A blade placement angle optimization design device for a high-speed and high-efficiency axial flow pump, characterized in that: include: A determination module, used to determine the inlet and outlet diameters, inlet and outlet axial surface speeds, inlet and outlet effective diameter circumferential speeds, inlet and outlet speed circumferential components and number of blades of a high-speed axial flow pump blade; A dividing module is used to divide the blade into sections at equal intervals from the impeller rim to the hub; Design module, used to design the inlet placement angle of blades with different sections using the free vortex method, and the outlet placement angle of blades using the forced vortex method; The division module divides the blade from the impeller rim to the hub into sections with equal spacing, namely rim, Span = 0.75, Span = 0.5, Span = 0.25 and hub. Among them, rim: Span = 1, hub: Span = 0. The variation law of the blade inlet placement angle along the blade span direction is expressed as follows: Span=1Inlet placement angle: Span=0.75Inlet placement angle: Span=0.5Inlet placement angle: Span=0.25Inlet placement angle: Span=0Inlet placement angle: Among them, v m1 is the inlet shaft speed, v u1 is the circular component of the inlet velocity, u1=πnD t1 / 60 is the circumferential velocity of the effective diameter at the inlet of the wheel rim, The circumferential velocity of the effective diameter of the inlet at 0.75Span; is the circumferential velocity of the effective diameter at the inlet at 0.5Span, The circumferential velocity of the effective diameter of the inlet at 0.25Span, is the effective diameter circumferential velocity at the hub, γ is the inlet attack angle; The variation law of blade outlet placement angle along the blade span direction is expressed as follows: Span=1Export placement angle: Span=0.75Export placement angle: Span=0.5Export placement angle: Span=0.25Export placement angle: Span=0 Exit placement angle: Among them, β2 is the outlet effective diameter placement angle, β2=β′2+Vβ2, outlet effective diameter liquid flow angle The outlet deviation angle Vβ2 is 0.72 o , is the circumferential component of the outlet velocity, m / s; u2=πnD t2 / 60 is the circumferential velocity of the effective diameter at the wheel rim, D 0.75-2 =(D t0.75-2 2 +D h0.75-2 2 ) / 2 is the effective diameter of the outlet at 0.75Span, D 0.5-2 =(D t0.5-2 2 +D h0.5-2 2 ) / 2 is the effective diameter of the outlet at 0.5Span, D 0.25-2 =(D t0.25-2 2 +D h0.25-2 2 ) / 2 is the effective outlet diameter at 0.25Span.

4. The blade placement angle optimization design device for a high-speed and high-efficiency axial flow pump according to claim 3 is characterized in that: Also includes: Thickening module, used to thicken the blades using the 791 airfoil thickening method.

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