Centrifugal pump impeller for shear-thinning non-newtonian fluid delivery and method of designing the same

Abstract

The present application relates to a kind of for shear thinning non-Newtonian fluid delivery centrifugal pump impeller and its design method, solve the existing problems of prior art, non-Newtonian fluid cannot be transported by centrifugal pump and need to be combined with other equipment to transport, the technical scheme used: shear blade is additionally arranged in the inner wall of the water inlet pipe of centrifugal pump impeller, and the distribution position of shear blade, various parameters of shear blade are set.Technical effect: by increasing several layers, several pieces of shear blade in the inner wall of the water inlet pipe of centrifugal pump impeller, shear blade rotates along with impeller when running, gradually shear thinning non-Newtonian fluid medium, and make the inlet pre-whirl speed of centrifugal pump impeller meet the requirements, by shear blade, reduce viscosity, reduce flow loss, to improve the efficiency of centrifugal pump, realize a device to meet the requirements of shear thinning non-Newtonian fluid, also meet the requirement of delivery efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water pump, especially to a centrifugal pump impeller for shear thinning non-Newtonian fluid delivery and a design method thereof BACKGROUND

[0002] Centrifugal pumps are widely used and extremely important for chemical industry, agriculture, food processing and other industries. Most of the conventional centrifugal pumps are used for transporting Newtonian fluid medium. For non-Newtonian fluid, because its flow does not comply with Newton's friction law, the viscosity is larger than that of Newtonian fluid, and before using the centrifugal pump for delivery, it often needs to be thinned to enhance its flowability and facilitate delivery. However, the existing centrifugal pump cannot simultaneously have the function of thinning non-Newtonian fluid, and needs to be used in cooperation with special thinning equipment for thinning first, which causes the delivery of non-Newtonian fluid to involve many devices, increases the cost of equipment, and also increases the time cost and hardware cost of setting, maintenance and replacement. SUMMARY

[0003] The present application aims to solve the above problems in the prior art and provides a centrifugal pump impeller for shear thinning non-Newtonian fluid delivery and a design method thereof. By increasing a plurality of layers of shear blades on the inner wall of the water inlet pipe of the centrifugal pump impeller, the shear blades rotate with the impeller during operation, gradually shear thinning the non-Newtonian fluid medium, and the inlet pre-whirling speed of the centrifugal pump impeller reaches the requirement. The shear blades thin the fluid, reduce the viscosity and reduce the flow loss, so as to improve the efficiency of the centrifugal pump, realize one device that meets the requirements of thinning non-Newtonian fluid and meets the requirements of delivery efficiency.

[0004] The above technical purposes of the present application are mainly solved by the following technical scheme: a centrifugal pump impeller for shear thinning non-Newtonian fluid delivery, comprising impeller blades, front and rear cover plates arranged on both sides of the impeller blades, a water inlet pipe in an integral structure with the front cover plate, wherein the end of the water inlet pipe away from the front cover plate is the impeller inlet, characterized in that the inner wall of the water inlet pipe is sequentially provided with a plurality of layers of shear blades from the impeller inlet, each layer is provided with a plurality of circumferentially uniformly arranged shear blades, the axial direction of the impeller is the vertical direction, and the direction perpendicular to the axial direction of the impeller is the horizontal direction. The shear blades of the first layer are arranged vertically to the horizontal direction, the shear blades of the second layer to the Nth layer are inclined to the rotation direction of the impeller and arranged at an angle to the horizontal direction, and N>2.

[0005] This technical solution adds several layers of shear blades, each with several blades, to the inner wall of the inlet pipe of the centrifugal pump impeller. During operation, the shear blades rotate with the impeller, progressively shearing and thinning the non-Newtonian fluid medium, and ensuring that the inlet pre-rotation speed of the centrifugal pump impeller meets the requirements. By thinning the fluid, reducing viscosity, and minimizing flow losses through the shear blades, the efficiency of the centrifugal pump is improved. This allows a single device to meet both the requirements for thinning non-Newtonian fluids and the requirements for conveying efficiency.

[0006] This technical solution also limits the configuration of the shear blades, which is beneficial to improving the efficiency of thinning non-Newtonian fluid media.

[0007] As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures: the inclination angle of the shear blades from the second layer to the Nth layer increases sequentially, and the inclination angle of the shear blades in each layer is the same. Further optimizing the arrangement of the shear blades is beneficial to further improving the efficiency and effect of thinning non-Newtonian fluid media.

[0008] Preferably, the number of shear blades in each layer is consistent with the number of impeller blades, and all shear blades are triangular, with the long base corresponding to the apex angle of the shear blade facing the direction of rotation of the impeller blades. This helps to dilute non-Newtonian fluid media while reducing hydraulic losses and ensuring the efficiency of the centrifugal pump.

[0009] Preferably, the apex angle of the shear blade is θ, where θ = 30° to 150°, the minimum base angle is γ, where γ = 10° to 45°, the height is h, where h = (0.01 to 0.1)R1, and the length of the base side is c. Where R1 is the inner diameter of the impeller inlet.

[0010] Preferably, the thickness of the shear blade is B, B = (0.1~1.0)b, the distance between the shear blade of the first layer and the impeller inlet is L1, L1 = (0~0.05)x; the distance between the shear blade of the Nth layer and the impeller inlet is L2, L2 = (0.05~0.15)x, where b is the thickness of the impeller blade; and x is the distance from the impeller inlet to the upper edge of the impeller blade.

[0011] Preferably, the inclination angles of the shear blades in the first to Nth layers are β1, β2, ..., β1, respectively. N , Among them, v z v is the axial velocity of the non-Newtonian fluid at the impeller inlet. u1 The inlet pre-rotation circumferential speed of the impeller blades.

[0012] Preferably, the spacing between adjacent shear blades is l. Among them, β1, β2...β NL1 represents the tilt angle of the shear blades from the first to the Nth layer, L2 represents the distance between the shear blade of the Nth layer and the impeller inlet, L1 represents the distance between the shear blade of the first layer and the impeller inlet, x represents the distance from the impeller inlet to the upper edge of the impeller blade, and c represents the length of the base.

[0013] This invention relates to another technical subject: a design method for a centrifugal pump impeller for shear-thinning non-Newtonian fluid transport, characterized in that the centrifugal pump impeller is the centrifugal pump impeller for shear-thinning non-Newtonian fluid transport described in the above-mentioned technical solutions, and its design steps include:

[0014] S1. Calculate the axial velocity of the non-Newtonian fluid at the impeller inlet:

[0015] S2. Design of shear blades:

[0016] S211, Calculate the tilt angle β of the shear blades in the Nth layer. N ;

[0017] S212, the cross-sectional shape of the shear blade in the Nth layer is triangular. Design the triangle parameters, which include the vertex angle θ, the minimum base angle γ, the height h, the thickness B, and the length of the base side c.

[0018] S213, adjacent shear blades on the same layer are spaced apart, and the length of the base side of the triangle needs to be controlled.

[0019] S221, Design the shear blades from the (N-1)th layer to the first layer;

[0020] S222, determine the tilt angle of each layer of shear blades;

[0021] S231, determine the position of the shear blades in each layer.

[0022] Further optimization, in step S1 according to the formula

[0023] Calculate the axial velocity of the non-Newtonian fluid at the impeller inlet, where Q is the centrifugal pump flow rate; v z R1 is the impeller inlet axial velocity; R2 is the impeller inlet radius.

[0024] In step S211, according to the formula

[0025] Calculate the tilt angle β of the shear blades in the Nth layer. N In the formula, v z v is the axial velocity of the non-Newtonian fluid at the impeller inlet. u1 The pre-rotation circumferential velocity at the blade inlet;

[0026] In step S212, according to the formula

[0027]

[0028] Design the triangle parameters of the shear blade of the Nth layer. The triangle parameters include the vertex angle θ, the minimum base angle γ, the height h, the thickness B, and the base side length c.

[0029] In step S213, according to the formula

[0030] Determine the spacing between adjacent shear blades on the same layer and control the length of the base of the triangle. If the c value calculated by equation (3) does not satisfy equation (4), redesign the triangle parameters until equation (4) is satisfied.

[0031] In step S221, according to the formula Combined with equation (2), the shear blades from the N-1th layer to the first layer are designed. The cross-sectional shape of the shear blades from the N-1th layer to the first layer is triangular, and its parameters are consistent with the parameters of the shear blades in the Nth layer. The tilt angle of each layer changes in a gradient.

[0032] In step S222, according to formula β N-s =β N +sΔβ, determine the tilt angle of each layer of shear blades.

[0033] In the formula, s is an integer, and its value ranges from 1 to 1. <s≤N-1;

[0034] In step S231, according to the formula Determine the position of the shear blades in each layer.

[0035] In the formula, L1 is the distance between the shear blades of the first layer and the impeller inlet, and L2 is the distance between the shear blades of the Nth layer and the impeller inlet. The spacing between each layer is l>0. If the requirements are not met, it is necessary to return to S211 to S213 and redesign until the requirements are met.

[0036] The design method for centrifugal pump impellers used for shear-thinning non-Newtonian fluid transport also includes a step of evaluating the shear-thinning effect of the shear blades on the non-Newtonian fluid, the steps of which include:

[0037] After designing the shear blades, the corresponding UDF (User-Defined Function) for the viscosity change of the non-Newtonian fluid is embedded into the CFD numerical simulation software. Through numerical simulation, the efficiency increase of the centrifugal pump after adding the shear blades is analyzed, and the shear thinning effect of the shear blades is evaluated. The values ​​of the various parameters of the shear blades can be selected within the range. If the requirements are not met, return to step S211 and adjust the inlet pre-rotation circumferential speed v. u1 Repeat steps S211-S231 and continue the simulation until the requirements are met, where the inlet pre-rotation circumferential speed v u1The shear thinning effect value ε is in the range of 0.1% to 30% according to experience, or CFD numerical simulation or test.

[0038] UDF is a self-defined function, CFD is a product of modern fluid mechanics, numerical mathematics and computer science, and is a cross science with strong vitality. It is to approximately express the integral and differential terms in the control equation of fluid mechanics as discrete algebraic forms, so as to make it into an algebraic equation group, and then to solve the discrete algebraic equation group by computer to obtain the numerical solution at discrete time / space points.

[0039] The present application has the beneficial effect that: by increasing several layers of shear blades on the inner wall of the water inlet pipe of the centrifugal pump impeller, the shear blades rotate with the impeller during operation, gradually shear thinning the non-Newtonian fluid medium, and the pre-whirl speed at the inlet of the centrifugal pump impeller meets the requirements, the fluid is thinned by the shear blades, the viscosity is reduced, the flow hydraulic loss is reduced, and the efficiency of the centrifugal pump is improved, so that one device meets the requirements of thinning non-Newtonian fluid and conveying efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a sectional view of the centrifugal pump impeller according to the present application.

[0041] Figure 2 is Figure 1 A-A direction structure diagram in the figure.

[0042] Figure 3 is Figure 1 B-B direction structure diagram in the figure.

[0043] Figure 4 is Figure 1 C-C direction structure diagram in the figure.

[0044] In the figure: 1, first layer of shear blades; 2, second layer of shear blades; 3, third layer of shear blades; 4, front cover plate; 5, rear cover plate; 6, hub; 7, water inlet pipe; 8, impeller inlet; R1, impeller inlet radius; x, distance from impeller inlet to upper edge of blade; h, height of triangle; B, thickness of triangle; θ, top angle of triangle; γ, minimum base angle of triangle; c, length of triangle side; β2, second layer of small blades inclination angle; β3, third layer of small blades inclination angle; L1, distance from first layer of small blades to impeller inlet; L2, distance from third (N) layer of small blades to impeller inlet; l, spacing between layers of small blades. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be further specifically described below by examples in combination with the drawings.

[0046] Example 1: As Figures 1-4 As shown, a centrifugal pump impeller for shearing and diluting non-Newtonian fluid transport includes impeller blades, a front cover plate 4 and a rear cover plate 5 disposed on both sides of the impeller blades, an inlet pipe 7 integrally formed with the front cover plate 4, the end of the inlet pipe 7 opposite to the front cover plate 4 being the impeller inlet 8, and a hub 6 integrally formed on the rear cover plate 5.

[0047] The main improvement of this technical solution is that: the inner wall of the water inlet pipe is provided with several layers of shearing blades from the impeller inlet inwards. Each layer is provided with several shearing blades evenly arranged in a circle. The vertical direction is the direction of the impeller axis, and the horizontal direction is the direction perpendicular to the impeller axis. The shearing blades of the first layer are arranged perpendicular to the horizontal direction. The shearing blades of the second to Nth layers are all inclined towards the impeller rotation direction and are arranged at an angle to the horizontal direction, where N>2.

[0048] This technical solution adds several layers of shear blades, each with several blades, to the inner wall of the inlet pipe of the centrifugal pump impeller. During operation, the shear blades rotate with the impeller, progressively shearing and thinning the non-Newtonian fluid medium, and ensuring that the inlet pre-rotation speed of the centrifugal pump impeller meets the requirements. By thinning the fluid, reducing viscosity, and minimizing flow losses through the shear blades, the efficiency of the centrifugal pump is improved. This allows a single device to meet both the requirements for thinning non-Newtonian fluids and the requirements for conveying efficiency.

[0049] At the same time, the setting method of the shear blades is also limited, which is beneficial to improving the efficiency of thinning non-Newtonian fluid media.

[0050] To further improve the efficiency and effectiveness of thinning non-Newtonian fluid media, the tilt angles of the shear blades from the second to the Nth layer increase sequentially, with each layer having the same tilt angle. The arrangement of the shear blades is further optimized.

[0051] While diluting the non-Newtonian fluid medium, in order to reduce hydraulic losses and ensure the efficiency of the centrifugal pump, the number of shear blades in each layer is consistent with the number of impeller blades. The shear blades are all triangular, and the long base corresponding to the apex of the shear blade is set towards the direction of rotation of the impeller blade.

[0052] The above technical solution is further specified as follows:

[0053] The apex angle of the shear blade is θ, where θ = 30° to 150°; the minimum base angle is γ, where γ = 10° to 45°; the height is h, where h = (0.01 to 0.1)R1; and the length of the base side is c. ， Where R1 is the inner diameter of the impeller inlet.

[0054] The thickness of the shear blade is B, B = (0.1~1.0)b, the distance between the first layer of shear blades and the impeller inlet is L1, L1 = (0~0.05)x; the distance between the Nth layer of shear blades and the impeller inlet is L2, L2 = (0.05~0.15)x, where b is the thickness of the impeller blades; x is the distance from the impeller inlet to the upper edge of the impeller blades.

[0055] The inclination angles of the shear blades from the first to the Nth layer are β1, β2, ..., β1, respectively. N , Among them, v z v is the axial velocity of the non-Newtonian fluid at the impeller inlet. u1 The inlet pre-rotation circumferential speed of the impeller blades.

[0056] The spacing between adjacent shear blades is l. Among them, β1, β2...β N L1 represents the tilt angle of the shear blades from the first to the Nth layer, L2 represents the distance between the shear blade of the Nth layer and the impeller inlet, L1 represents the distance between the shear blade of the first layer and the impeller inlet, x represents the distance from the impeller inlet to the upper edge of the impeller blade, and c represents the length of the base.

[0057] Example 2: This invention relates to another technical subject, namely, a design method for a centrifugal pump impeller for shear-thinning non-Newtonian fluid transport, based on the centrifugal pump impeller for shear-thinning non-Newtonian fluid transport described in Example 1. The design steps include:

[0058] S1. Calculate the axial velocity of the non-Newtonian fluid at the impeller inlet:

[0059] S2. Design the shear blades:

[0060] S211, Calculate the tilt angle β of the shear blades in the Nth layer. N ;

[0061] S212, the cross-sectional shape of the shear blade in the Nth layer is triangular. Design the triangle parameters, which include the vertex angle θ, the minimum base angle γ, the height h, the thickness B, and the length of the base side c.

[0062] S213, adjacent shear blades on the same layer are spaced apart, and the length of the base side of the triangle needs to be controlled.

[0063] S221, Design the shear blades from the (N-1)th layer to the first layer;

[0064] S222, determine the tilt angle of each layer of shear blades;

[0065] S231, determine the position of the shear blades in each layer.

[0066] Further optimize the above steps:

[0067] In the S1 step, according to the formula

[0068] The non-Newtonian fluid axial flow velocity of the impeller inlet is calculated, wherein Q is the flow rate of the centrifugal pump; v z is the axial velocity of the impeller inlet; R1 is the radius of the impeller inlet;

[0069] In the S211 step, according to the formula

[0070] The inclination angle β of the shear blade of the Nth layer is calculated N , wherein v z is the non-Newtonian fluid axial flow velocity of the impeller inlet; v u1 is the pre-whirl peripheral velocity of the blade inlet;

[0071] In the S212 step, according to the formula

[0072]

[0073] The triangular parameters of the shear blade of the Nth layer are designed, including the top angle θ, the minimum base angle γ, the height h, the thickness B, and the base side length c;

[0074] In the S213 step, according to the formula

[0075] The interval arrangement between adjacent shear blades of the same layer is determined, and the base side length of the triangle is controlled. If the value of c calculated by formula (3) does not satisfy formula (4), the triangular parameters are redesigned until formula (4) is satisfied;

[0076] In the S221 step, according to the formula and combined with formula (2), the shear blades of the N-1th layer to the first layer are designed. The cross-sectional shape of the shear blades of the N-1th layer to the first layer is a triangle, and the parameters are consistent with those of the shear blade of the Nth layer. The inclination angles of the layers change in a gradient manner;

[0077] In the S222 step, according to the formula β N-s = β N + sΔβ, the inclination angles of the shear blades of the layers are determined,

[0078] wherein s is an integer, and the value range is 1 < s ≤ N-1;

[0079] In the S231 step, according to the formula the positions of the shear blades of the layers are determined,

[0080] In the formula, L1 is the distance between the first layer of shear blades and the impeller inlet, L2 is the distance between the Nth layer of shear blades and the impeller inlet, and the interval between layers l>0. If the requirement is not met, the process returns to S211 to S213 for redesign until the requirement is met.

[0081] Embodiment 3: includes all the contents of Embodiment 2, and adds steps, mainly embodied in: the design method of the centrifugal pump impeller for shear-thinning non-Newtonian fluid conveying also includes the step of evaluating the shear-thinning effect of the shear blade on the non-Newtonian fluid, and the step includes:

[0082] After the shear blade is designed, the UDF (i.e. user-defined function) of the viscosity change of the corresponding non-Newtonian fluid is implanted into the CFD numerical simulation software, the efficiency increase value of the centrifugal pump after adding the shear blade is analyzed through numerical simulation, the shear-thinning effect of the shear blade is evaluated, and the parameter values of the shear blade can be selected within the value range. If the requirement is not met, the process returns to step S211 to adjust the inlet pre-whirl circumferential velocity v u1 , and repeats steps S211-S231 to continue simulation until the requirement is met. The inlet pre-whirl circumferential velocity v u1 may be assumed according to experience, or obtained through CFD numerical simulation and test.

[0083] UDF is a user-defined function, CFD is a product of modern fluid mechanics, numerical mathematics and computer science, and is a cross science with strong vitality. It is to approximately express the integral and differential terms in the control equation of fluid mechanics as discrete algebraic forms, so as to become algebraic equations, and then solve these discrete algebraic equations through a computer to obtain numerical solutions at discrete time / space points.

[0084] The above embodiments are verified and described as follows:

[0085] A non-Newtonian fluid centrifugal pump is taken as a research object, the number of impeller blades Z=6, the design flow rate Q=100 L / s, the design rotating speed n=5500 r / min, the impeller inlet radius R1=25 mm, the distance from the impeller inlet to the upper edge of the blade x=25 mm, and the requirement is ε>10%.

[0086] The design method according to the application increases shear blades on the inner wall of the water inlet pipe, the cross-sectional shape of the shear blades is triangular, there are three layers, the top angle is θ=110°, the minimum base angle is γ=25°, the height is h=0.1R1=2.5mm, and the thickness is B=1mm. The distance between the third layer of shear blades and the blade inlet is L2=0.1x=2.5mm; the distance between the first layer of shear blades and the impeller inlet is L1=0.04x=1mm; the number of shear blades is consistent with the number of blades of the centrifugal pump, which is 6 pieces per layer. According to experience, it is assumed that the pre-whirl circumferential velocity v u1 of the impeller inlet is 17m / s. Other design parameters are calculated as follows.

[0087] The inclination angle of the third layer of shear blades is calculated as follows:

[0088]

[0089]

[0090] The inclination angles of the second layer and the first layer of shear blades are calculated as follows:

[0091]

[0092] β2=β 3-1 =β3+1×Δβ=64.3°

[0093] β1=β 3-2 =β3+2×Δβ=90°

[0094] The length of the base side of the triangle is calculated as follows:

[0095]

[0096] Therefore, the design meets the requirements.

[0097] The distance between layers is calculated as follows:

[0098]

[0099] The shear blades designed above are applied to a centrifugal pump, and CFD numerical simulation is performed. Comparative analysis shows that ε=14.5%, which meets the requirements.

[0100] In conclusion, it is proved that the design method of the inlet shear blades is scientific and reasonable, and has important practical application value.

[0101] The above only describes the preferred embodiments of the application and is not used to limit the application. In the above embodiments, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.​

Claims

1. A centrifugal pump impeller for shear-thinning non-Newtonian fluid delivery, comprising impeller blades, a front shroud and a rear shroud arranged on both sides of the impeller blades, a water inlet pipe integrated with the front shroud, and an end of the water inlet pipe away from the front shroud being an impeller inlet, characterized in that The inner wall of the water inlet pipe is provided with a plurality of layers of shearing blades from the impeller inlet, each layer is provided with a plurality of shearing blades arranged uniformly in a circle, the axial direction of the impeller is taken as the vertical direction, and the horizontal direction is perpendicular to the axial direction of the impeller, the shearing blades of the first layer are arranged perpendicularly to the horizontal direction, the shearing blades of the second layer to the Nth layer are inclined to the rotating direction of the impeller and arranged at an angle with the horizontal direction, and N>2; The top angle of the shearing blade is θ, θ = 30°-150°, the minimum bottom angle is γ, γ = 10°-45°, the height is h, h = (0.01-0.1)R1, the bottom side length is c, Wherein, R1 is the inner diameter of the impeller inlet; The inclination angles of the shearing blades of the second layer to the Nth layer are increased successively, and the inclination angles of the shearing blades of each layer are the same; The number of the shearing blades of each layer is consistent with the number of the impeller blades, the shearing blades are triangular, and the long bottom edge corresponding to the top angle of the shearing blades is arranged towards the rotating direction of the impeller blades; The thickness of the shearing blades is B, B=(0.1-1.0)b, the distance between the shearing blades of the first layer and the impeller inlet is L1, L1=(0-0.05)x, the distance between the shearing blades of the Nth layer and the impeller inlet is L2, L2=(0.05-0.15)x, wherein b is the thickness of the impeller blades, and x is the distance from the impeller inlet to the upper edge of the impeller blades.

2. A centrifugal pump impeller for shear-thinning non-Newtonian fluid delivery according to claim 1, characterized in that The inclination angles of the shearing blades of the first layer to the Nth layer are β1, β2, …, βN respectively. N , Wherein, v z is the axial flow velocity of the non-Newtonian fluid at the impeller inlet; v u1 is the inlet pre-whirl peripheral speed of the impeller blade.

3. The centrifugal pump impeller for shear-thinning non-Newtonian fluid delivery of claim 1, wherein The distance between adjacent layers of shear blades is l, wherein β1, β2, … βN N respectively are the inclination angles of the shear blades of the first layer to the Nth layer, L2 is the distance between the shear blade of the Nth layer and the impeller inlet, L1 is the distance between the shear blade of the first layer and the impeller inlet, x is the distance from the impeller inlet to the upper edge of the impeller blade, and c is the base length.

4. A method of designing a centrifugal pump impeller for shear-thinning non-Newtonian fluid delivery, characterized in that The centrifugal pump impeller for shearing and transporting a shear-thinning non-Newtonian fluid is the centrifugal pump impeller for shearing and transporting a shear-thinning non-Newtonian fluid according to any one of claims 1-3, and the design steps include: S1, calculating the axial flow velocity of the non-Newtonian fluid at the impeller inlet; S2, designing shearing blades; S211, calculate the inclination angle β of the shearing blade of the Nth layer N ; S212, the cross-sectional shape of the shearing blades of the Nth layer is triangular, and the triangular parameters are designed, the triangular parameters including a top angle θ, a minimum bottom angle γ, a height h, a thickness B and a bottom edge length c; S213, the adjacent shearing blades of the same layer are arranged at intervals, and the bottom edge length of the triangle needs to be controlled; S221, designing the shearing blades of the N-1th layer to the first layer; S222, determining the inclination angles of the shearing blades of each layer; S231, determining the positions of the shearing blades of each layer.

5. The design method of the centrifugal pump impeller for shearing and transporting a shear-thinning non-Newtonian fluid according to claim 4, characterized in that: In the S1 step according to the formula The non-Newtonian fluid axial flow velocity at the impeller eye is calculated, where Q is the centrifugal pump flow rate; v z is the impeller eye axial velocity; R1 is the impeller eye radius; In step S211 the formula calculating the angle of inclination β of the shearing vanes of the Nth stage N where v z is the axial flow velocity of the non-Newtonian fluid at the impeller inlet; and v u1 is the pre-whirl peripheral velocity at the blade inlet in the step S212, the triangular parameters of the shearing blades of the Nth layer are designed according to the formula the triangular parameters including a top angle θ, a minimum bottom angle γ, a height h, a thickness B and a bottom edge length c; In step S213, the formula the adjacent shearing blades of the same layer are arranged at intervals, and the bottom edge length of the triangle needs to be controlled, if the value of c calculated by the formula (3) does not satisfy the formula (4), the triangular parameters are redesigned until the formula (4) is satisfied; In step S221, according to the formula And combined with formula (2), the shear vane of the N-1th layer to the first layer is designed, the cross-sectional shape of the shear vane of the N-1th layer to the first layer is a triangle, the parameters of which are consistent with each parameter of the shear vane of the Nth layer, and the inclination angles of each layer change in a gradient. In step S222 the tilt angle of the shear blade of each layer is determined according to the formula N-s = β N + sΔβ, in the formula, s is an integer, and the value range is 1<s≤N-1; In step S231 the position of the shear blade of each layer is determined according to the formula determining the position of the shear blade of each layer, in the formula, L1 is the distance between the shearing blades of the first layer and the impeller inlet, L2 is the distance between the shearing blades of the Nth layer and the impeller inlet, and the interval l of each layer is greater than 0, if the requirement is not met, the steps S211 to S213 need to be returned to be redesigned until the requirement is met.

6. The method of designing a centrifugal pump impeller for shear-thinning non- Newtonian fluid delivery according to claim 5, wherein: The method further includes a step of judging the shearing and thinning effect of the shearing blades on the non-Newtonian fluid, and the steps include: After the shear blade is designed well, the UDF of viscosity change of the corresponding non-Newtonian fluid is implanted into the CFD numerical simulation software, the efficiency increase value of the centrifugal pump after the shear blade is added is analyzed through numerical simulation, the shear thinning effect of the shear blade is judged, and the parameter values of the shear blade can be selected in the value range, if the requirement is not met, the inlet pre-rotation circumferential velocity v u1 is adjusted, the steps S211-S231 are repeated, and the simulation is continued until the requirement is reached, wherein the inlet pre-rotation circumferential velocity v u1 may be assumed according to experience, or obtained through CFD numerical simulation and test, and the value range of the shear thinning effect value ε is 0.1% to 30%.

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