Centrifugal pump impeller for pumping dilute non-newtonian fluids and method of designing the same

Abstract

The present application relates to a centrifugal pump impeller for stirring dilution non-Newtonian fluid conveying and a design method thereof, and solves the problem that the centrifugal pump cannot or inefficiently convey non-Newtonian fluid existing in the prior art, and the technical scheme and technical effects are as follows: a vortex generator is arranged in front of the centrifugal pump impeller and a corresponding design method is formed, so that the stirring column arranged in the cone part has the function of stirring dilution non-Newtonian fluid, and the sawtooth groove arranged on the stirring column can further enhance the dilution effect, the fluid entering the flow channel of the centrifugal pump through the centrifugal pump impeller with the front vortex generator has stronger flowability, the conveying effect is greatly improved, the power consumption of the centrifugal pump is reduced, and the conveying efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of centrifugal pump, in particular to a centrifugal pump impeller for stirring dilution of non-Newtonian fluid conveying and a design method thereof. BACKGROUND

[0002] Centrifugal pumps are widely used in various aspects of life, and are indispensable to industrial production, agricultural production, etc. Due to the unique high viscosity physical properties of non-Newtonian fluid, the effect of using conventional centrifugal pumps for conveying is often unsatisfactory. It is often necessary to set a dilution device in front of the centrifugal pump for dilution before conveying through the centrifugal pump. This conveying method requires more equipment, increases equipment cost, and increases installation, maintenance efficiency and cost, which is inconvenient for use. SUMMARY

[0003] The present application aims to solve the above problems existing in the prior art and provide a centrifugal pump impeller for stirring dilution of non-Newtonian fluid conveying and a design method thereof. A vortex generator is arranged in the centrifugal pump impeller, and a stirring column arranged in the conical portion has the function of stirring dilution of non-Newtonian fluid. The sawtooth groove arranged on the stirring column can further enhance the dilution effect. The fluid entering the centrifugal pump flow passage through the centrifugal pump impeller with the front vortex generator has stronger flowability, greatly improves the conveying effect, reduces the power consumption of the centrifugal pump, and improves the conveying efficiency.

[0004] The above technical purposes of the present application are mainly solved by the following technical scheme: a centrifugal pump impeller for stirring dilution of non-Newtonian fluid conveying, comprising a front cover plate, a rear cover plate, and impeller blades arranged in the cooperation area of the front cover plate and the rear cover plate, the front cover plate has an outwardly convex water inlet pipe, and the rear cover plate has a hub, characterized in that a conical vortex generator is arranged in the centrifugal pump impeller, the bottom end of the vortex generator is connected to the hub, the sharp end penetrates the center of symmetry of the impeller blades and passes out of the water inlet pipe, and an extension is formed at the outer end of the water inlet pipe, in the axial direction, a plurality of layers of stirring columns are arranged on the outer wall of the vortex generating part of the vortex generator, in the circumferential direction, a plurality of stirring columns are arranged in each layer, the number of layers is Z, Z=2-8, the number of stirring columns in each layer is consistent with the number of layers in the layer, and the stirring columns are arranged outside the outer edge of the inlet of the impeller blades.

[0005] The centrifugal pump impeller for stirring dilution of non-Newtonian fluid conveying is the first protection subject of the present patent application.

[0006] In the technical solution, the improvement lies in that a vortex generator is arranged in front of the impeller of the centrifugal pump, and the stirring column arranged in the cone part has the function of stirring the dilution of non-Newtonian fluid, the fluid entering the flow channel of the centrifugal pump through the impeller with the front vortex generator has stronger flowability, the conveying effect is greatly improved, the power consumption of the centrifugal pump is reduced, the conveying efficiency is improved, and no other special dilution equipment is needed, so that the requirements of dilution of non-Newtonian fluid and conveying efficiency are met by one device.

[0007] In the technical solution, the arrangement mode of the stirring column is limited, which is beneficial to further improve the effect and efficiency of the dilution of non-Newtonian fluid medium.

[0008] As a further improvement and supplement to the above technical solution, the present application adopts the following technical measures: the stirring column is a right-angle stirring column, the first right-angle surface on the stirring column is fixed on the vortex generating part, the second right-angle surface on the stirring column is arranged towards the tip direction of the vortex generator, and the inclined surface on the stirring column is arranged towards the impeller blade, the width of the second right-angle surface is h1, h1=(0.01-0.5)R, the width of the first right-angle surface is h2, h2=h1 tan β, R is the bottom radius of the vortex generating part, the angle between the second right-angle surface and the inclined surface is β, and the angle between the second right-angle surface and the inclined surface is equal to the angle formed between the inlet plane of the impeller blade and the inlet plane of the water inlet pipe. The stirring column is further optimized, so that the stirring column cooperates with the conical vortex generating part to form a vortex for stirring and diluting non-Newtonian fluid, and the effect of stirring and diluting non-Newtonian fluid can be further improved.

[0009] As a preferred embodiment, the intersection between the inclined surface and the first right-angle surface is provided with a sawtooth groove, the sawtooth groove is arranged along the length direction of the stirring column, the number of the sawtooth grooves is N, N=2-10, the groove depth of the sawtooth groove is h', the groove width of the sawtooth groove is b, and h is the height of the stirring column. The sawtooth groove is arranged on the stirring column, and the arrangement position, arrangement mode and corresponding parameters of the sawtooth groove are limited, so that the dilution effect can be further improved.

[0010] As a preferred embodiment, each sawtooth unit in the sawtooth groove is triangular, or the sawtooth groove is in a sinusoidal shape, when the sawtooth groove is triangular, the base angle is θ, when the sawtooth groove is in a sinusoidal shape, the intersection line between the inclined surface and the first right-angle surface is taken as the x-axis, the width direction of the first right-angle surface is taken as the y-axis, and the shape of the sinusoidal wave is determined by the function . For the sawtooth groove, the preferred shapes are triangular and sinusoidal, and other shapes are not excluded. The triangular and sinusoidal shapes mentioned herein mainly refer to the shape of the sawtooth groove projected on the first right-angle surface.

[0011] The height of the stirring column is h=(0.1-0.8)R, R is the bottom radius of the vortex generator, and the bottom radius of the stirring column is consistent with the outer diameter of the inner end of the hub. The vortex generator and the stirring column form a reasonable proportion, which is beneficial to increase the stirring area of the stirring column, improve the stirring effect, and increase the vortex effect, thereby improving the conveying effect of the agitated dilution of the non-Newtonian fluid.

[0012] The vortex generator is located at the height H outside the impeller blade, the vortex generator has a threaded connection part, the threaded connection part is threadedly connected with the inner wall of the hub, and the taper angle of the vortex generator is γ, It is beneficial to improve the vortex of the non-Newtonian fluid which is beneficial to the stirring dilution effect.

[0013] In order to further improve the stirring column for stirring and diluting the non-Newtonian fluid, from the outside of the impeller to the inside, the layers where the stirring columns are located are sequentially the first layer, the second layer,..., and the i layer, i is an integer, 2≤i≤Z, the distance from the first layer stirring column to the top of the taper of the vortex generator is l1, The distance between the stirring columns of adjacent layers is Δl, Wherein, l2 is the distance from the last layer stirring column to the upper edge of the inlet of the impeller blade, l2=1mm-10mm, and l3 is the distance between the outer edge of the inlet of the impeller blade and the inner end of the hub.

[0014] The radius r of the cross section of the vortex generator at the position of each layer of the stirring column i ,

[0015] The circumferential angle of each stirring column in each layer is:

[0016]

[0017] The circumferential angle Δα between adjacent stirring columns in the same layer i , That is

[0018] Another subject protected by the application is: a design method of a centrifugal pump impeller for stirring and diluting non-Newtonian fluid conveying, wherein the centrifugal pump impeller involved is the centrifugal pump impeller for stirring and diluting non-Newtonian fluid conveying involved in the above technical solution, and the design steps include:

[0019] S1, designing a vortex generator:

[0020] A conical vortex generator and a threaded connection part below the vortex generator are formed, the bottom radius of the vortex generator is R, the height of the vortex generator outside the impeller blade is H, the height of the threaded connection part is H', the radius r of the threaded connection part is equal to the inner diameter of the hub, and r < R;

[0021] S2, design stirring column:

[0022] A plurality of layers of stirring columns are formed on the outer wall of the vortex generator, each layer has a plurality of stirring columns in the circumferential direction, the number of layers is Z, Z = 2-8, the number of stirring columns in each layer is consistent with the number of layers in the layer, the stirring column adjacent to the impeller blade is arranged outside the inlet outer edge of the impeller blade, the stirring column is a right-angle stirring column, the first right-angle surface thereon is fixed on the vortex generator, the second right-angle surface thereon is arranged towards the tip of the vortex generator, and the inclined surface thereon is arranged towards the bottom of the vortex generator;

[0023] S3, design sawtooth groove on stirring column:

[0024] The sawtooth groove is arranged at the junction of the inclined surface and the first right-angle surface, the sawtooth groove is arranged along the length direction of the stirring column, and the number of sawtooth grooves is N, N = 2-10.

[0025] S4, detect design effect:

[0026] The vortex generator designed through S1-S3 is applied to a centrifugal pump for transporting non-Newtonian fluid, numerical simulation is performed on the centrifugal pump using CFD software, the value ξ is used to detect the stirring and thinning effect, when the value of ξ is in the range of 5%≤ξ≤30%, the stirring and thinning effect meets the requirements, and the vortex generator designed through S1-S3 meets the requirements.

[0027] Further optimize the above technical solutions:

[0028] In the S1 step, the taper angle of the vortex generator is γ,

[0029] In the S2 step,

[0030] ① Design parameters of stirring column

[0031] The height of the stirring column is h, the width of the second right-angle surface is h1, h1 = (0.01-0.5)R, the width of the first right-angle surface is h2, h2 = h1 tanβ, the angle between the second right-angle surface and the inclined surface is β, and the angle is equal to the angle formed between the inlet plane of the impeller blade and the inlet plane of the water inlet pipe;

[0032] ② Determine the position of each layer of stirring columns

[0033] The number of layers of the stirring column is Z, the number of stirring columns placed in each layer is consistent with the number of layers, and each stirring column is welded with a cone to form a whole;

[0034] From the outside of the impeller to the inside, the layers of the stirring column are the first layer, the second layer,..., and the i-th layer in order, i is an integer, 2≤i≤Z, and the distance from the first layer of the stirring column to the top of the cone of the vortex generating part is l1:

[0035]

[0036] The distance between the stirring columns of adjacent layers is Δl:

[0037]

[0038] In the formula: l2 is the distance from the last layer of the stirring column to the upper edge of the inlet of the impeller blade, and l3 is the distance between the outer edge of the inlet of the impeller blade and the inner end of the hub.

[0039] The radius of the cross section of the vortex generating part at the position of each stirring column in each layer:

[0040]

[0041] The circumferential angle occupied by each stirring column in each layer is:

[0042]

[0043] The circumferential angle between adjacent stirring columns in the same layer is Δα i :

[0044]

[0045] Combined with the above formulas (5), (6), and (7), the final expression of Δα i can be obtained:

[0046]

[0047] In the formula: i is an integer, and the value range is [2, Z];

[0048] In the S3 step,

[0049] The sawtooth groove is triangular or sinusoidal, the groove depth h' of the sawtooth groove is The groove width of the sawtooth groove is h is the height of the stirring column;

[0050] When the sawtooth groove is triangular, the bottom angle is θ,

[0051] When the sawtooth groove is a sine wave shape:

[0052] The sine wave shape is determined by a function y = sin (x), wherein the intersection line of the inclined surface and the first right-angled surface is the x-axis, and the width direction of the first right-angled surface is the y-axis. A coordinate system is established with a point on the intersection line of the second right-angled surface and the inclined surface as the coordinate origin, and a sine function with an expression of y = sin (x) is used to determine the sine wave shape of the sawtooth groove.

[0053] In the S4 step,

[0054] The axial flow velocity uniformity V u1 and V u2 of the impeller blade at the inlet outer edge cross section are calculated under the conditions of prepositioning the vortex generator and not setting the vortex generator. u1 If V u2 ≥ξ, it indicates that the stirring and thinning effect meets the requirements, and if the condition is not met, the vortex generator is redesigned by returning to the S1-S3 steps, and the above calculation is continued until the requirements are met.

[0055] The axial flow velocity uniformity calculation formula is as follows:

[0056]

[0057] In the formula, v ai is the axial velocity (m / s) of the selected point on the cross section at the impeller blade inlet; is the axial average velocity (m / s) of the cross section at the impeller blade inlet; and m is the number of selected points on the cross section at the impeller blade inlet.

[0058] The present application has the following beneficial effects: 1. A vortex generator is prepositioned in the centrifugal pump impeller, the stirring column provided in the cone portion has the effect of stirring and thinning the non-Newtonian fluid, the sawtooth groove provided on the stirring column can further enhance the thinning effect, the fluid entering the centrifugal pump flow passage through the centrifugal pump impeller has stronger flowability, the conveying effect is greatly improved, the power consumption of the centrifugal pump is reduced, and the conveying efficiency is improved. 2. The specific structure and setting mode of the stirring column are combined with the vortex flow generating portion in the cone shape to form the vortex flow beneficial to stirring and thinning the non-Newtonian fluid, and the effect of stirring and thinning the non-Newtonian fluid can be further enhanced. 3. The sawtooth groove is provided on the stirring column, and the setting position, setting mode and corresponding parameters of the sawtooth groove are limited, and the thinning effect can be further enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 is a structural schematic view of the centrifugal pump impeller with the prepositioned vortex generator.

[0060] Figure 2 ​Figure 1 Cross-sectional structure schematic view of A-A section.

[0061] Figure 3 Figure 1 Cross-sectional structure schematic view of B-B section.

[0062] Figure 4 Figure 1 Cross-sectional structure schematic view of C-C section.

[0063] Figure 5 Structure schematic view involved in the present application.

[0064] Figure 6 Structure schematic view involved in the present application, in which the sawtooth slot is triangular.

[0065] Figure 7 Structure schematic view involved in the present application, in which the sawtooth slot is sinusoidal.

[0066] In the figure: 1, front cover plate; 2, rear cover plate; 3, water inlet pipe; 4, hub; 5, vortex generator; 7, first layer of stirring column; 8, second layer of stirring column; 9, third layer of stirring column; 10, vortex generating part; 11, R, outer diameter of inner end of hub, also the bottom radius of vortex generating part; r, inner diameter of inner end of hub; H, height of vortex generating part located on the outside of impeller blade; γ, taper angle of vortex generating part; l1, distance from first layer of stirring column to the top of vortex generating part; l2, distance from last layer of stirring column to the upper edge of inlet of impeller blade; l3, distance between the outer edge of inlet of impeller blade and inner end of hub; Δl, spacing between adjacent layers of stirring columns; h, height of stirring column; h1, width of first right-angled face; h2, width of second right-angled face; r1, r2, r3, cross-sectional radii of vortex generating part at positions of first layer of stirring column, second layer of stirring column, third layer of stirring column, respectively; α2, α3, circumferential angles occupied by first layer of stirring column, second layer of stirring column (i.e. circumferential angles occupied by short side of second right-angled face of corresponding layer of stirring column); Δα3, circumferential included angle between adjacent stirring columns of a layer; β, included angle between second right-angled face and said inclined face; h', groove depth of sawtooth slot; b, groove width of sawtooth slot; L3, distance between the outer edge of inlet of impeller blade and inner end of said hub. DETAILED DESCRIPTION

[0067] The technical solutions of the present application will be further specifically described below by way of examples in conjunction with the accompanying drawings.

[0068] Example 1: As shown in the figure, the centrifugal pump impeller for stirring dilution non-Newtonian fluid delivery is the first protection subject of the present patent application. Figures 1-7

[0069] ​The centrifugal pump impeller for stirring dilution of non-Newtonian fluid delivery comprises a front cover plate 1, a rear cover plate 2, and impeller blades arranged in the cooperation area of the front cover plate and the rear cover plate, wherein the front cover plate has an outward convex water inlet pipe 3, and the rear cover plate has a hub 4.

[0070] The main improvement of the technical solution is that a conical vortex generator is arranged in the centrifugal pump impeller, the bottom end of the vortex generator is connected to the hub, the tip end penetrates the symmetry center of the impeller blade and extends out of the water inlet pipe, an extension is formed at the outer end of the water inlet pipe, in the axial direction, a plurality of layers of stirring columns are arranged on the outer wall of the vortex generating part of the vortex generator, in the circumferential direction, a plurality of stirring columns are arranged in each layer, the number of layers is Z, Z=2-8, the number of stirring columns in each layer is consistent with the number of layers in the layer, and the stirring columns are arranged outside the outer edge of the impeller blade inlet.

[0071] The plurality of layers of stirring columns comprise a first layer of stirring columns 7, a second layer of stirring columns 8, a third layer of stirring columns 9, and a Zth layer of stirring columns, as shown in Figure 1 only three layers of stirring columns are shown.

[0072] In the technical solution, the improvement is that a vortex generator is arranged in the centrifugal pump impeller, the stirring columns arranged in the conical part of the vortex generator have the function of stirring dilution of non-Newtonian fluid, the fluid entering the flow channel of the centrifugal pump through the impeller with the front vortex generator has stronger flowability, the delivery effect is greatly improved, the power consumption of the centrifugal pump is reduced, the delivery efficiency is improved, and other special dilution equipment is not needed, so that one device meets the requirements of dilution of non-Newtonian fluid and delivery efficiency.

[0073] In the technical solution, the arrangement mode of the stirring columns is limited, which is beneficial to further improving the effect and efficiency of dilution of non-Newtonian fluid medium.

[0074] The stirring column is optimized: the stirring column is a right-angle stirring column, the first right-angle surface on the stirring column is fixed on the vortex generating part, the second right-angle surface on the stirring column is arranged towards the tip end of the vortex generator, the inclined surface on the stirring column is arranged towards the impeller blade, the width of the second right-angle surface is h1, h1=(0.01-0.5)R, the width of the first right-angle surface is h2, h2=h1tanβ, R is the bottom radius of the vortex generating part, the included angle between the second right-angle surface and the inclined surface is β, and the included angle between the second right-angle surface and the inclined surface is equal to the included angle between the inlet plane of the impeller blade and the inlet plane of the water inlet pipe. The stirring column is further optimized, the stirring column cooperates with the conical vortex generating part to form a vortex for stirring dilution of non-Newtonian fluid, and the effect of stirring dilution of non-Newtonian fluid can be further improved.

[0075] As preferred, the intersection between the inclined surface and the first right-angled surface is provided with a sawtooth groove, the sawtooth groove is arranged along the length direction of the stirring column, the number of the sawtooth grooves is N, N=2-10, the groove depth of the sawtooth groove is h', the groove width of the sawtooth groove is b, h is the height of the stirring column. The sawtooth groove is arranged on the stirring column, and the arrangement position, arrangement mode and corresponding parameters of the sawtooth groove are limited, which can further enhance the thinning effect.

[0076] As preferred, each sawtooth unit in the sawtooth groove is triangular, or the sawtooth groove is in the shape of a sine wave. When it is triangular, the base angle is θ, When it is in the shape of a sine wave, the intersection line between the inclined surface and the first right-angled surface is the x axis, the width direction of the first right-angled surface is the y axis, and the shape of the sine wave is determined by the function . For the sawtooth groove, the preferred shapes are triangular and sine wave shape, and other shapes are not excluded. The triangular and sine wave shape mentioned herein mainly refers to the shape of the sawtooth groove projected on the first right-angled surface.

[0077] The height h of the stirring column is (0.1-0.8)R, R is the bottom radius of the vortex generating part, and the bottom radius of the stirring column is consistent with the outer diameter of the inner end of the hub. The vortex generating part and the stirring column form a reasonable proportion, which is conducive to increasing the stirring area of the stirring column, improving the stirring effect, increasing the vortex effect, and further improving the conveying effect of the stirring thinning non-Newtonian fluid.

[0078] The height of the vortex generating part on the outer side of the impeller blade is H, the vortex generator is provided with a threaded connection part, the threaded connection part is threadedly connected with the inner wall of the hub, and the taper angle of the vortex generating part is γ, which is conducive to improving the vortex of the non-Newtonian fluid to form a stirring thinning effect.

[0079] In order to further improve the stirring thinning of the non-Newtonian fluid by the stirring column, from the outer side of the impeller to the inside, the layers where the stirring columns are located are the first layer, the second layer, …, the i-th layer, i is an integer, 2≤i≤Z, the distance from the first layer stirring column to the top of the taper of the vortex generating part is l1, the distance between the stirring columns of adjacent layers is Δl, wherein l2 is the distance from the last layer stirring column to the upper edge of the inlet of the impeller blade, l2=1mm-10mm, and l3 is the distance between the outer edge of the inlet of the impeller blade and the inner end of the hub;

[0080] The radius r of the cross section of the vortex generating part at the position of each layer of the stirring column is i ,

[0081] The circumferential angle size of each of the stirring columns of each layer is:

[0082]

[0083] The circumferential angle between adjacent stirring columns of the same layer is Δα i , That is

[0084] Embodiment 2: A specific embodiment of another subject matter protected by the present application: a design method of a centrifugal pump impeller for stirring and transporting a dilute non-Newtonian fluid, wherein the centrifugal pump impeller involved is the centrifugal pump impeller for stirring and transporting a dilute non-Newtonian fluid involved in Embodiment 1, as shown in Figures 1-7 .

[0085] The design steps of the design method of the centrifugal pump impeller for stirring and transporting a dilute non-Newtonian fluid include:

[0086] S1, design a vortex generator:

[0087] A conical vortex generator and a threaded connection part located below the vortex generator are formed, the bottom radius of the vortex generator is R, the height of the vortex generator on the outer side of the impeller blade is H; the height of the threaded connection part is H', the radius r of the threaded connection part is equal to the inner diameter of the hub, r < R;

[0088] S2, design a stirring column:

[0089] A plurality of layers of stirring columns are formed on the outer wall of the vortex generator, each layer has a plurality of stirring columns in the circumferential direction, the number of layers is Z, Z = 2-8, the number of stirring columns of each layer is consistent with the number of layers of the layer, the stirring column adjacent to the impeller blade is arranged outside the inlet outer edge of the impeller blade, the stirring column is a right-angle stirring column, the first right-angle surface thereon is fixed on the vortex generator, the second right-angle surface thereon is arranged towards the tip of the vortex generator, and the inclined surface thereon is arranged towards the bottom of the vortex generator;

[0090] S3, design a sawtooth groove on the stirring column:

[0091] The sawtooth groove is arranged at the junction between the inclined surface and the first right-angle surface, the sawtooth groove is arranged along the length direction of the stirring column, and the number of sawtooth grooves is N, N = 2-10.

[0092] S4, detect the design effect:

[0093] The vortex generator designed by S1-S3 is applied to a centrifugal pump transporting non-Newtonian fluid, numerical simulation is performed on the centrifugal pump by using CFD software, the stirring dilution effect is detected by using value ξ, when the value of ξ is in the range of 5%≤ξ≤30%, the stirring dilution effect meets the requirements, and the vortex generator designed by S1-S3 meets the requirements.

[0094] Further optimize the above technical solutions:

[0095] In the S1 step, the taper angle of the vortex generating part is γ,

[0096] In the S2 step,

[0097] ③ Design parameters of the stirring column

[0098] The height of the stirring column is h, the width of the second right-angled surface is h1, h1=(0.01-0.5)R, the width of the first right-angled surface is h2, h2=h1 tan β, the included angle between the second right-angled surface and the inclined surface is β, and is equal to the included angle formed between the inlet plane of the impeller blade and the inlet plane of the water inlet pipe;

[0099] ④ Determine the position of each layer of stirring column

[0100] The number of layers of the stirring column is Z, the number of stirring columns placed in each layer is consistent with the number of layers, and each stirring column is welded with a cone to form a whole;

[0101] From the outside of the impeller to the inside, the layers of the stirring column are the first layer, the second layer,..., and the i-th layer in turn, i is an integer, 2≤i≤Z, and the distance from the first layer of stirring column to the cone top of the vortex generating part is l1:

[0102]

[0103] The spacing between the stirring columns of adjacent layers is Δl:

[0104]

[0105] In the formula, l2 is the distance from the last layer of stirring column to the upper edge of the inlet of the impeller blade, and l3 is the distance between the outer edge of the inlet of the impeller blade and the inner end of the hub.

[0106] The radius of the cross section of the vortex generating part at the position of each stirring column in each layer is:

[0107]

[0108] The circumferential angle occupied by each stirring column in each layer is:

[0109]

[0110] The circumferential included angle Δα between adjacent said stirring columns in the same layer i :

[0111]

[0112] In combination with the above formula (5), (6), (7), Δα i The final expression of Δα

[0113]

[0114] In the formula, i is an integer, and the value range is [2, Z];

[0115] In the S3 step,

[0116] The sawtooth groove is triangular or sinusoidal, the groove depth h' of the sawtooth groove, The groove width of the sawtooth groove h is the height of the stirring column;

[0117] When the sawtooth groove is triangular, the bottom angle is θ,

[0118] When the sawtooth groove is sinusoidal:

[0119] The intersection line of the inclined surface and the first right-angled surface is the x-axis, the width direction of the first right-angled surface is the y-axis, and the shape of the sine wave is determined by the function The coordinate system is established with the point on the intersection line of the second right-angled surface and the inclined surface as the coordinate origin, and the sine function with the expression is used to determine the sinusoidal sawtooth groove;

[0120] In the S4 step,

[0121] The axial flow velocity uniformity V u1 and V u2 at the inlet outer edge cross section of the impeller blade are calculated under the conditions of prepositioning the vortex generator and not setting the vortex generator, if V u1 -V u2 ≥ξ, it indicates that the stirring dilution effect meets the requirements, if the condition is not met, the vortex generator is redesigned in S1-S3 step, and the above calculation is continued until the requirements are met;

[0122] Wherein, the axial flow velocity uniformity calculation formula is:

[0123]

[0124] In the formula: v aiThe axial velocity (m / s) of the selected point on the cross section at the impeller blade inlet; The axial average velocity (m / s) of the cross section at the impeller blade inlet; m is the number of selected points on the cross section at the impeller blade inlet.

[0125] Embodiment 3: One specific embodiment of the centrifugal pump impeller for stirring and thinning non-Newtonian fluid delivery and the design method thereof: Taking a centrifugal pump for delivering non-Newtonian fluid as the research object, the number of impeller blades is 6, the design flow rate Q is 100 L / s, the design rotating speed n is 5500 r / min, the impeller inlet radius is 60 mm, the hub head outer diameter R is 40 mm, the inner diameter r is 35 mm, the distance l3 from the blade inlet upper edge to the hub head of the impeller is 30 mm, and the requirement is that ξ>15%.

[0126] The front vortex generator of the centrifugal pump is designed according to the design method of the application, the conical bottom radius R is taken as H=3R=120 mm, the screw rod is taken as H'=4R=16 mm; three layers of three-prism stirring columns are designed, the height h is 0.4R=16 mm, the distance l2 from the last layer of three-prism to the blade inlet upper edge is taken as 5 mm, and the cross-sectional right-angled triangle height h1 is 0.25R=10 mm. Five sawtooth grooves are designed, and a sine wave shape is adopted. Through CFD numerical calculation, the angle between the fluid velocity of the blade inlet without the front vortex generator and the inlet plane is 35°, so β=35°. Therefore, the three-prism right-angled side h2=h1 tan β=7 mm. Other parameters are calculated as follows:

[0127] The conical cone angle γ:

[0128]

[0129] The distance l1 of the first layer of three-prism from the cone top:

[0130]

[0131] l1=18 mm is taken.

[0132] The spacing Δl of each three-prism in the impeller axial direction:

[0133]

[0134] The circumferential angle Δα3 between each three-prism of the third layer:

[0135]

[0136] The sawtooth groove depth h' is in the range of That is, 1.4 mm≤h'≤3.5 mm, h'=3.5 mm is taken; the groove width Therefore, the sine wave function expression of the sawtooth groove is

[0137] The designed stirring column is applied to the centrifugal pump, and CFD numerical simulation is carried out. It is found that ξ=18.9%, which meets the requirements.

[0138] In summary, it is proved that the design method of the centrifugal pump pre-whirl generator is scientific and reasonable, and has important practical application value.

[0139] The above only describes the preferred embodiments of the present application and is not used to limit the present application. In the above embodiments, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A centrifugal pump impeller for pumping dilute non-Newtonian fluids comprising a front shroud, a rear shroud, impeller vanes disposed in the interface region of said front shroud and rear shroud, said front shroud having an outwardly convex inlet tube, said rear shroud having a hub, characterized in that The centrifugal pump impeller is provided with a conical vortex generator at the front end of the impeller, the bottom end of the vortex generator is connected to the hub, the tip end penetrates the symmetry center of the impeller blade and extends out of the water inlet pipe, and an extension is formed at the outer end of the water inlet pipe; in the axial direction, a plurality of layers of stirring columns are arranged on the outer wall of the vortex generating part of the vortex generator, and in the circumferential direction, each layer has a plurality of stirring columns, the number of layers is Z, Z=2-8, the number of stirring columns in each layer is consistent with the number of layers in the layer, and the stirring columns adjacent to the impeller blade are arranged outside the inlet edge of the impeller blade. The stirring column is a right-angle stirring column, a first right-angle surface thereof is fixed on the vortex generating part, a second right-angle surface thereof is arranged towards the tip end of the vortex generator, and an inclined surface thereof is arranged towards the bottom of the vortex generating part; the width of the second right-angle surface is h1, h1=(0.01-0.5)R; the width of the first right-angle surface is h2, h2=h1 tan β, R is the bottom radius of the vortex generating part, the included angle between the second right-angle surface and the inclined surface is β, and the included angle between the second right-angle surface and the inclined surface is equal to the included angle between the inlet plane of the impeller blade and the inlet plane of the water inlet pipe. The junction part of the inclined surface and the first right-angle surface is provided with a sawtooth groove, the sawtooth groove is arranged along the length direction of the stirring column, the number of the sawtooth grooves is N, N=2-10, the groove depth of the sawtooth groove is h', The groove width of the sawtooth groove is b, h is the height of the stirring column.

2. The centrifugal pump impeller for agitating dilute non-Newtonian fluid delivery of claim 1, wherein Each of the sawtooth units in the sawtooth groove is a triangle, or the sawtooth groove is a sine wave shape, and when it is a triangle, the base angle is θ, When it is a sine wave shape, the intersection line of the inclined surface and the first right-angled surface is the x-axis, the width direction of the first right-angled surface is the y-axis, and the shape of the sine wave is a function is determined.

3. A centrifugal pump impeller for agitating dilute non-Newtonian fluid delivery according to claim 1 or 2, characterized in that The height of the stirring column is h=(0.1-0.8)R, R is the bottom radius of the vortex generating part, and the bottom radius of the stirring column is consistent with the outer diameter of the inner end of the hub.

4. A centrifugal pump impeller for agitating dilute non-Newtonian fluid delivery according to claim 1 or 2, characterized in that The vortex generator is located at the height H outside the impeller blade, the vortex generator has a threaded connection part, the threaded connection part is in threaded connection with the inner wall of the hub, the taper angle of the vortex generator is γ, 5. A method for designing a centrifugal pump impeller for pumping dilute non-Newtonian fluids with agitation, characterized by: The centrifugal pump impeller for stirring and diluting non-Newtonian fluid transportation according to any one of claims 1-4 comprises the following design steps: S1, designing a vortex generating part: forming a conical vortex generating part and a threaded connecting part below the vortex generating part, the bottom radius of the vortex generating part is R, the height of the vortex generating part outside the impeller blade is H; the height of the threaded connecting part is H', the radius r of the threaded connecting part is equal to the inner diameter of the hub, and r S2, designing a stirring column: forming a plurality of layers of stirring columns on the outer wall of the vortex generating part, each layer has a plurality of stirring columns in the circumferential direction, the number of layers is Z, Z=2-8, the number of stirring columns in each layer is consistent with the number of layers in the layer, the stirring columns adjacent to the impeller blade are arranged outside the inlet edge of the impeller blade, the stirring column is a right-angle stirring column, a first right-angle surface thereof is fixed on the vortex generating part, a second right-angle surface thereof is arranged towards the tip end of the vortex generator, and an inclined surface thereof is arranged towards the bottom of the vortex generating part; S3, designing a sawtooth groove on the stirring column: the sawtooth groove is arranged at the junction of the inclined surface and the first right-angle surface, the sawtooth groove is arranged along the length direction of the stirring column, and the number of sawtooth grooves is N, N=2-10; S4, detecting the design effect: applying the vortex generator designed through S1-S3 to a centrifugal pump for transporting non-Newtonian fluid, performing numerical simulation on the centrifugal pump by using CFD software, using the value ξ to detect the stirring and diluting effect, when the value of ξ is in the range of 5%≤ξ≤30%, the stirring and diluting effect meets the requirements, and the vortex generator designed through S1-S3 meets the requirements.

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