Method for manufacturing centrifugal pump impeller structure

Abstract

The present invention discloses a method for manufacturing a centrifugal pump impeller structure, which includes a rear cover plate and at most two blades arranged on the rear cover plate, wherein the blades are arranged on the rear cover plate in a spiral shape, one end of the blades is placed in the middle of the rear cover plate area, and the other end of the blades extends to the edge of the rear cover plate. The present invention arranges at most two blades on the rear cover plate, and cooperates with the design of two key parameters, namely, the ratio of the relative velocity of the blade outlet to the relative velocity of the inlet, and the ratio of the axial velocity of the blade inlet to the velocity of the water suction chamber inlet, to avoid excessive deceleration or acceleration of the fluid inside the impeller structure, thereby significantly improving the operation efficiency and stability of the pump.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal pumps, and in particular to a method for manufacturing a centrifugal pump impeller structure. Background Art

[0002] With the acceleration of urbanization and the vigorous development of industrial production, the demand for sewage treatment is increasing, which puts higher requirements on the performance of sewage pumps.

[0003] like Figure 1 and Figure 2 As shown in Figure 1, traditional centrifugal pump structural design often focuses on the general principles of fluid dynamics, but faces challenges when treating wastewater containing large particles. Specifically, the standard impeller structure has a large number of blades and a limited outlet width, which not only easily leads to clogging problems, affecting the smooth passage of large particles, but also limits the overall efficiency of the pump.

[0004] In view of this situation, a new impeller structure and a manufacturing method thereof are urgently needed to solve the problems raised. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a method for manufacturing a centrifugal pump impeller structure, which can effectively treat sewage containing large particles and significantly improve the operating efficiency and stability of the pump.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for manufacturing a centrifugal pump impeller structure, the centrifugal pump impeller structure comprising a rear cover plate and at most two blades arranged on the rear cover plate, the blades are spirally arranged on the rear cover plate, one end of the blade is placed in the middle of the rear cover plate area, and the other end of the blade extends to the edge of the rear cover plate;

[0007] The manufacturing method of the centrifugal pump impeller structure comprises the following steps:

[0008] S1. Design flow rate according to the centrifugal pump impeller structure Q , Lift H , speed n Determining the specific speed of a centrifugal pump impeller structure n s :

[0009] (1);

[0010] S2, based on the specific speed of the centrifugal pump n s , preset the pump efficiency η and volumetric efficiency of the centrifugal pump η v and mechanical efficiency η m , get the theoretical head of the centrifugal pump:

[0011] (2)

[0012] S3. Get the impeller outlet diameter D 2 and the theoretical specific speed of the centrifugal pump under the condition of limited number of blades n sth :

[0013] (3),

[0014] (4),

[0015] Where g is the acceleration due to gravity, K u2 is the impeller outlet peripheral velocity coefficient, K u2 =-0.711 ln ( n sth )+4.3643;

[0016] S4, based on the slip coefficient s and load coefficient at the impeller blade outlet k Get the relative velocity of the impeller blade outlet w 2 and relative speed of impeller blade inlet w 1:

[0017] (5),

[0018] (6),

[0019] w 1= w 2 / k (7),

[0020] (8),

[0021] (9),

[0022] Among them, β2 is the blade outlet placement angle, u 2 is the circumferential speed at the blade outlet, Z is the number of impeller blades, is the impeller outlet axial velocity, is the circumferential thickness at the blade outlet, b 2 is the blade outlet width;

[0023] S5. Obtain blade inlet axial velocity , water absorption chamber inlet speed , blade inlet placement angle β1 and suction chamber inlet diameter D 0:

[0024] (10),

[0025] (11),

[0026] (12),

[0027] (13),

[0028] in, D 1 is the impeller inlet diameter, is the circumferential thickness at the blade inlet, b1 is the blade inlet width, and K is the suction port flow rate ratio;

[0029] S6, given impeller inlet diameter D 1An initial value D 11 and the blade inlet width b1 has an initial value b 11 , and then substitute into formulas (3) to (12) to obtain the blade inlet axial velocity Initial value of and the initial value of the blade inlet placement angle β1 12 :

[0030] ,

[0031] ;

[0032] S7, based on iterative formula , β 1(p+1) =β 1p , D 1（p+1） =D 1p 、b 1（p+1） =b 1p The initial value , , D 11 、b 11 Substitute into formulas (3) to (12) to obtain the updated blade inlet axial velocity , Blade inlet placement angle β 1(p+1) And blade inlet diameter D 1（p+1） :

[0033] (14),

[0034] (15),

[0035] (16),

[0036] Where p=1, 2, 3, 4, ...;

[0037] S8, based on iterative formula b 1（p+1） =b 1p And formula (15) to obtain the blade inlet width b 1（p+1） :

[0038]

[0039] When b 1（p+1） -b 1p When the difference is within the preset threshold, the iteration stops and the following is obtained:

[0040] Suction chamber inlet diameter D The final value of 0 satisfies:

[0041] , ;

[0042] The final value of the blade inlet placement angle β1 is β1=β 1(p+1) ,

[0043] ;

[0044] The final value of the blade inlet width b1 is b1=b 1（p+1） ,

[0045] ;

[0046] Impeller inlet diameter D The final value of 1 is D1=D 1（p+1） ,

[0047] .

[0048] Furthermore, the method further comprises the following steps:

[0049] S9. Establish a rectangular coordinate system to obtain the contour of the blade working surface:

[0050] r=D1 ·e λ / 2, x=r·cos(T·360), y=r·sin(T·360);

[0051] The blade working surface is the side surface corresponding to the arc-shaped convex side of the blade, e=2.71828, λ=2πT×(m1 · (360T / θ) M +tanβ1), ,

[0052] , , θ is the blade wrap angle, θ =150°~300°; in the rectangular coordinate system, r, x, and y refer to the polar radius, the coordinate value of the x-axis, and the coordinate value of the y-axis, respectively.

[0053] Furthermore, the following steps are included:

[0054] S10, obtaining the contour of the back side of the blade; wherein the method for obtaining the contour of the back side of the blade is:

[0055] Get the maximum thickness of the leaf ;

[0056] The thickening rule of the blade along the working surface of the blade meets the following requirements:

[0057] ,

[0058]

[0059] in, l i Refers to the first i The length of the arc from a node to the blade inlet position; l Refers to the entire arc length of the blade working surface contour; t i Refers to the first i The thickness is increased vertically at each point.

[0060] Furthermore, the method for obtaining the contour of the back side of the blade further includes:

[0061] When the blade is thickened, the working surface contour can be divided into N 1 node, N 1=10~20, measure the arc length from each node to the blade inlet l i , with the equally divided node as the center, and its corresponding t i Draw a circle with the value as the radius, outlining the back face outline, which remains tangent to all the drawn circles.

[0062] Furthermore, in step S3, the theoretical specific speed of the centrifugal pump under the condition of a limited number of blades is obtained. n sth The method is:

[0063] Theoretical head of centrifugal pump H th Replace the lift of centrifugal pump H , substituting into formula (1), the theoretical specific speed of the centrifugal pump under the condition of limited number of blades is obtained nsth :

[0064] (4).

[0065] Furthermore, the b The value of 2 must satisfy b 2=(1~1.1) d , the initial value b of the blade inlet width b1 11 Satisfy b 11 = (1.1~1.2) d , the blade outlet placement angle β2 = 15°~35°.

[0066] Furthermore, the load factor k =1.1~1.8, the suction port flow rate ratio K=0.3~0.8.

[0067] Furthermore, the number of impeller blades Z = 1 or Z = 2.

[0068] Compared with the prior art, the manufacturing method of the centrifugal pump impeller structure of the present invention has the following beneficial effects:

[0069] 1. Refined step design: The present invention adopts a more refined step design, integrating all aspects of the centrifugal pump impeller structure design, and realizes seamless connection from theoretical prediction to practical application through precise calculation and parameter optimization. The present invention overcomes the uncertainty caused by reliance on experience judgment and trial and error in the traditional centrifugal pump impeller structure design, greatly shortens the product iteration cycle, and improves the design efficiency and success rate.

[0070] 2. Introduction of load factor and suction port velocity ratio: The present invention introduces the ratio of blade outlet relative velocity to inlet relative velocity (load factor k ) and the ratio of the blade inlet axial velocity to the suction chamber inlet velocity (inlet velocity ratio K). The setting of these two key parameters helps to balance the fluid mechanics characteristics inside the impeller structure of the centrifugal pump, avoid excessive deceleration or acceleration of the fluid inside the impeller, and thus significantly improve the operating efficiency and stability of the centrifugal pump.

[0071] 3. Enhanced particle passing capacity: By optimizing the design of the number of impeller blades and the blade inlet width, the present invention successfully solves the common clogging problem of traditional centrifugal pumps when treating sewage containing large particles; specifically, by reducing the number of blades and appropriately widening the flow channel width between blades, it effectively ensures the smooth passage of particulate matter, significantly improving the application range and processing capacity of the pump.

[0072] 4. Improved efficiency and reduced energy consumption: The centrifugal pump impeller structure of the present invention utilizes the relative velocity of the blade outlet w2 is much greater than the relative speed of the blade inlet w 1. Accelerate the flow and greatly reduce energy loss while ensuring sufficient head. Compared with the traditional design, the impeller designed in the present invention generally improves the pump efficiency by more than 20% under the same working conditions, significantly saves energy consumption, and meets the needs of green production and energy conservation and emission reduction.

[0073] In summary, the manufacturing method of a centrifugal pump impeller structure of the present invention sets at most two blades on the rear cover plate, and cooperates with the design of two key parameters: the ratio of the blade outlet relative velocity to the inlet relative velocity and the ratio of the blade inlet axial velocity to the suction chamber inlet velocity, so as to avoid excessive deceleration or acceleration of the fluid inside the impeller structure, thereby significantly improving the operating efficiency and stability of the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a structural cross-sectional view of an existing conventional centrifugal pump impeller structure;

[0075] Figure 2 A schematic diagram of the structure of a rear cover plate of an existing conventional centrifugal pump impeller structure;

[0076] Figure 3 A structural cross-sectional view of a centrifugal pump impeller structure of the present invention;

[0077] Figure 4 It is a structural schematic diagram of a rear cover plate of a centrifugal pump impeller structure of the present invention;

[0078] Figure 5 It is a schematic diagram of the outline of the back side of the blade of the present invention;

[0079] Figure 6 A schematic diagram showing the comparison of the efficiency performance of the centrifugal pump impeller structure of the present invention and that of a conventional impeller;

[0080] Figure 7 A schematic diagram comparing the cavitation performance of the centrifugal pump impeller structure of the present invention and that of a conventional impeller;

[0081] Figure 8 A schematic diagram showing a comparison of the solid particle passing capacity of the centrifugal pump impeller structure of the present invention and a conventional impeller at different solid particle concentrations;

[0082] Fig. 9 The figure is a schematic diagram comparing the solid particle passing capacity of the centrifugal pump impeller structure of the present invention and the traditional impeller at different impeller outlet widths. DETAILED DESCRIPTION

[0083] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0084] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0085] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] See also Figure 3 and Figure 4 The present invention provides a centrifugal pump impeller structure including a rear cover plate 10 and at most two blades 20 arranged on the rear cover plate 10. The blades 20 are arranged on the rear cover plate 10 in a spiral shape, one end of the blade 20 is placed in the middle of the rear cover plate 10 area, and the other end of the blade 20 extends to the edge of the rear cover plate 10; specifically, a hub is provided in the middle of the rear cover plate 10 area, and the innermost position of one end of the blade 20 after being projected on the rear cover plate 10 is placed at the outer edge of the hub; by reducing the number of blades 20 and appropriately widening the flow channel width between the blades 20, the smooth passage of particulate matter is effectively guaranteed, and the application range and processing capacity of the pump are significantly improved.

[0087] In one embodiment, the blade 20 gradually becomes thinner from the middle part toward the two ends to optimize the mechanical properties and fluid dynamic characteristics of the blade 20, which not only significantly improves the overall efficiency of the pump, but also optimizes its anti-cavitation performance, and can provide a more advanced technical solution for the sewage treatment industry.

[0088] In one embodiment, the centrifugal pump impeller structure also includes a front cover plate 30, which is docked with the rear cover plate 10, and the blades 20 are placed in the space between the front cover plate 30 and the rear cover plate 10; the front cover plate 30, the rear cover plate 10 and the blades 20 are all made of wear-resistant and corrosion-resistant materials to adapt to the harsh working conditions in sewage treatment and effectively improve the life of the impeller.

[0089] In one embodiment, the surfaces of the front cover plate 30, the rear cover plate 10 and the blades 20 are provided with a drag-reducing coating to further reduce flow resistance, further enhance the reliability of the centrifugal pump in a harsh sewage treatment environment, and effectively improve the pumping efficiency.

[0090] In one embodiment, the working surface of the blade 20 and the back surface of the blade 20 are both arranged perpendicular to the rear cover plate 10, so that the blade 20 is in a non-twisted state at the impeller inlet, effectively meeting the flow capacity requirements of the centrifugal pump impeller structure.

[0091] Furthermore, in order to meet the flow capacity requirements of the centrifugal pump impeller structure, it is necessary to ensure that the diameter of the impeller can pass through 20 blades. d The blade 20 wrap angle θ needs to be adjusted appropriately until the particle passing capacity requirement is met. In this embodiment, θ =150°~300°.

[0092] In order to balance the fluid mechanics characteristics inside the impeller structure of the centrifugal pump of the present invention, avoid excessive deceleration or acceleration of the fluid inside the impeller structure, and significantly improve the operating efficiency and stability of the pump, the present invention correspondingly provides a method for manufacturing a centrifugal pump impeller structure, the centrifugal pump impeller structure comprising a rear cover plate 10 and at most two blades 20 arranged on the rear cover plate 10, the blades 20 are spirally arranged on the rear cover plate 10, one end of the blades 20 is placed in the middle of the rear cover plate 10 area, and the other end of the blades 20 extends to the edge of the rear cover plate 10.

[0093] The manufacturing method of the centrifugal pump impeller structure comprises the following steps:

[0094] S1. Design flow rate according to the centrifugal pump impeller structure Q , Lift H , speed n Determining the specific speed of a centrifugal pump impeller structure n s :

[0095] (1).

[0096] S2, based on the specific speed of the centrifugal pump n s , preset the pump efficiency η and volumetric efficiency of the centrifugal pump η v and mechanical efficiency ηm , get the maximum head or height to which the centrifugal pump can lift the liquid:

[0097] (2),

[0098] in, H th Refers to the theoretical head of the centrifugal pump, that is, under ideal conditions, without considering any energy loss, such as friction loss, leakage loss, etc., the maximum head or height of the liquid that the pump can provide; in this embodiment, the pump efficiency of the centrifugal pump η The preset value range is 65%-85%, and the volumetric efficiency η v The preset value range is 90%-95%, and the mechanical efficiency η m The preset value range is 85%-98%.

[0099] S3. Get the impeller outlet diameter D 2 and the theoretical specific speed of the centrifugal pump under the condition of limited number of blades n sth :

[0100] (3),

[0101] (4),

[0102] Where g is the acceleration due to gravity, K u2 is the impeller outlet peripheral velocity coefficient, K u2 =-0.711 ln ( n sth )+4.3643, K u2 The value varies with the specific speed of the centrifugal pump. n sth In this embodiment, based on formula (4) and K u2 and n sth The relationship K u2 =-0.711 ln ( n sth )+4.3643, we can get K u2 The specific value of K u2 After substituting the specific value of into formula (3), the specific value of the impeller outlet diameter D2 can be known.

[0103] Furthermore, in step S3, the theoretical specific speed of the centrifugal pump under the condition of a limited number of blades is obtained. n sth The method is:

[0104] Centrifugal pump head H It will change with the change of pump efficiency, using the theoretical head of the centrifugal pump H th Replace the lift of centrifugal pump H , substituting into formula (1), we can get the theoretical specific speed of the centrifugal pump under the condition of limited number of blades. n sth :

[0105] (4).

[0106] S4, based on the slip coefficient s and load coefficient at the impeller blade outlet k Get the relative velocity of the impeller blade outlet w 2 and relative speed of impeller blade inlet w 1:

[0107] (5),

[0108] (6),

[0109] w 1= w 2 / k (7),

[0110] (8),

[0111] (9),

[0112] Among them, β2 is the blade outlet placement angle, u 2 is the circumferential speed at the blade outlet, Z is the number of impeller blades, is the impeller outlet axial velocity, is the circumferential thickness at the blade outlet, b 2 is the blade outlet width; in this embodiment, the blade outlet placement angle β2 = 15°~35°.

[0113] In this embodiment, the circumferential thickness at the blade outlet is defined as: a virtual circle with the impeller center as the center and the distance from the outlet end point corresponding to the arc line of the back side of the blade to the impeller center as the radius, and the arc length of the virtual circle sandwiched by the arc line of the back side of the blade and the arc line of the working surface of the blade.

[0114] In order to smoothly pass particles of a given diameter through the flow channel formed between the blades, it is necessary to select as few blades as possible, generally set to single blade or double blade, that is, Z = 1 or Z = 2. Especially when the particle size is large, the single blade structure is a reasonable choice.

[0115] In traditional designs, the flow in the centrifugal pump impeller is usually "deceleration flow", but excessive deceleration will cause the boundary layer to thicken and separate, especially in places where the curvature of the impeller hub side is large, serious flow separation will occur, resulting in reduced impeller efficiency. Since the number of blades in the present invention is relatively small, the slip effect of the impeller blades will be relatively significant, and the relative speed of the blade outlet will be w 2 is much greater than the relative speed of the blade inlet w 1, thereby forming accelerated flow and effectively improving the overall efficiency of the centrifugal pump; in this embodiment, k =1.1~1.8.

[0116] Specifically, the present invention adopts a single blade or double blade design, with a load factor k Presetting has the following effects:

[0117] 1. Effectively reduce friction loss and energy loss: The flow channel is widened and the number of blades is reduced, which reduces the friction area between the fluid and the blades and the centrifugal pump housing, thereby reducing friction loss; in addition, the overall flow velocity of the fluid is more uniform. Although the slip effect will cause local uneven velocity, on the whole, the wider flow channel helps to evenly distribute the fluid between the blades, reducing the formation of turbulence and eddy currents, thereby reducing energy loss.

[0118] 2. Optimize energy transfer: The blade force is more concentrated, and fewer blades make each blade have a greater force on the fluid, which can convert more mechanical energy into kinetic energy in a shorter time, improving the efficiency of energy transfer; the fluid is accelerated, and the relative speed of the blade outlet w 2 is much greater than the relative speed of the blade inlet w 1. A significant accelerated flow is formed, which enables the fluid to have higher kinetic energy when leaving the impeller, thereby increasing the head and flow of the pump.

[0119] 3. Reduce backflow and leakage: Reduce backflow. Fewer blades can reduce backflow between blades because wider flow channels reduce the possibility of fluid return; reduce leakage. Wider flow channels also help reduce leakage of fluid from high-pressure areas to low-pressure areas, further improving the overall efficiency of the pump.

[0120] In this embodiment, for a sewage centrifugal pump, when the maximum diameter of the particles passing through is d When the blade outlet width b 2 Needs to be satisfiedb 2> d relationship, in b 2> d At the request of b 2 Set a value. When the centrifugal pump passes through sewage particles with large size, in order to avoid velocity distortion in the width direction of the impeller outlet, in this embodiment, b The value of 2 must satisfy b 2=(1~1.1) d .

[0121] S5. Obtain blade inlet axial velocity , water absorption chamber inlet speed , blade inlet placement angle β1 and suction chamber inlet diameter D 0:

[0122] (10),

[0123] (11),

[0124] (12),

[0125] (13),

[0126] in, D 1 is the impeller inlet diameter, is the circumferential thickness of the blade at the inlet, b1 is the blade inlet width, and K is the suction port flow rate ratio.

[0127] In the design of traditional sewage pumps, it is necessary to consider using as few blades as possible and a larger blade inlet width b1 to ensure the effective passage of sewage particles. Therefore, the flow channel section at the blade inlet becomes much larger than the flow channel section at the suction port of the suction chamber. For this reason, when the fluid entering from the suction port changes direction near the blade inlet, from axial to radial, the flow velocity drops sharply, resulting in uneven flow. This excessive reduction in flow velocity near the blade inlet leads to low efficiency of traditional centrifugal pumps.

[0128] Therefore, in order to improve the working efficiency of the centrifugal pump, the present invention sets the suction port flow rate ratio K when designing the impeller structure; in this embodiment, K=0.3~0.8.

[0129] In this embodiment, for a sewage centrifugal pump, when the maximum diameter of the particles passing through is d When the blade inlet width b 1 Need to be satisfied b 1> d relationship, in b 1> d At the request of b1 sets an initial value. When the centrifugal pump passes through sewage with large particle size, in order to avoid velocity distortion in the width direction of the impeller inlet, in this embodiment, b The initial value of 1 must satisfy b 1=(1.1~1.2) d .

[0130] S6, given impeller inlet diameter D 1An initial value D 11 and the blade inlet width b1 has an initial value b 11 , and then substitute into formulas (3) to (12) to obtain the blade inlet axial velocity Initial value of and the initial value of the blade inlet placement angle β1 12 :

[0131] ,

[0132] ,

[0133] Among them, the initial value of b1 is b 11 Satisfy b 11 = (1.1~1.2) d .

[0134] S7, based on iterative formula , β 1(p+1) =β 1p , D 1（p+1） =D 1p 、b 1（p+1） =b 1p The initial value , , D 11 、b 11 Substitute into formulas (3) to (12) to obtain the updated blade inlet axial velocity , Blade inlet placement angle β 1(p+1) And blade inlet diameter D 1（p+1） :

[0135] (14),

[0136] (15),

[0137] (16),

[0138] Among them, p=1, 2, 3, 4...

[0139] S8, based on iterative formula b 1（p+1） =b1p And formula (15) to obtain the blade inlet width b 1（p+1） :

[0140]

[0141] When b 1（p+1） -b 1p When the difference is within the preset threshold, the iteration stops. At this time, the specific numerical result of p is obtained, and then the following can be obtained:

[0142] Suction chamber inlet diameter D The final value of 0 satisfies:

[0143] , ;

[0144] The final value of the blade inlet placement angle β1 is β1=β 1(p+1) ,

[0145] ;

[0146] The final value of the blade inlet width b1 is b1=b 1（p+1） ,

[0147] ;

[0148] Impeller inlet diameter D The final value of 1 is D1=D 1（p+1） ,

[0149] , thus finally determining the main parameters of the centrifugal pump impeller structure of the present invention, the suction chamber inlet diameter D 0. Impeller inlet diameter D 1. Impeller outlet diameter D 2. Blade inlet width b 1. Blade outlet width b 2. The blade inlet placement angle β1 and the blade outlet placement angle β2. The centrifugal pump impeller structure that meets the above parameter requirements can significantly improve the overall efficiency and anti-cavitation performance of the sewage centrifugal pump. Figure 6 A schematic diagram showing the comparison of the efficiency performance of the centrifugal pump impeller structure of the present invention and the traditional impeller is shown. Figure 7 The schematic diagram shows the comparison of the cavitation performance of the centrifugal pump impeller structure of the present invention and the traditional impeller; in this embodiment, the preset threshold range is [-10 -2 , 10 -2 ].

[0150] In one embodiment, based on the main parameters of the centrifugal pump impeller structure determined above, the inlet diameter of the suction chamber D 0. Impeller inlet diameterD 1. Impeller outlet diameter D 2. Blade inlet width b 1. Blade outlet width b 2. The blade inlet placement angle β1 and the blade outlet placement angle β2. The manufacturing method of the centrifugal pump impeller structure of the present invention further includes the following steps:

[0151] S9. Establish a rectangular coordinate system to obtain the contour of the blade working surface:

[0152] r=D1 ·e λ / 2, x=r·cos(T·360), y=r·sin(T·360);

[0153] The blade working surface is the side surface corresponding to the arc-shaped convex side of the blade, e=2.71828, λ=2πT×(m1 · (360T / θ) M +tanβ1), , , , θ is the blade wrap angle. In this embodiment, θ =150°~300°; in the rectangular coordinate system, r, x, and y refer to the polar radius, the coordinate value of the x-axis, and the coordinate value of the y-axis respectively.

[0154] The present invention provides a method for manufacturing a centrifugal pump impeller structure, further comprising the following steps:

[0155] S10. Obtain the contour of the back of the blade; the blade adopts a thickening method with a thick middle and thin inlet and outlet to optimize the mechanical properties and fluid dynamics characteristics of the blade, and improve the strength and durability of the blade through a specific thickening rule. Figure 8 A schematic diagram showing the comparison of the solid particle passing capacity of the centrifugal pump impeller structure of the present invention and the conventional impeller at different solid particle concentrations is shown. Fig. 9 A schematic diagram showing the comparison of the solid particle passing capacity of the centrifugal pump impeller structure of the present invention and the traditional impeller at different impeller outlet widths is shown.

[0156] In one embodiment, the method of obtaining the contour of the back side of the blade in step S10 comprises the following specific steps:

[0157] Get the maximum thickness of the leaf ;

[0158] The thickening rule of the blade along the working surface of the blade meets the following requirements:

[0159] ,

[0160]

[0161] in, l i Refers to the first i The length of the arc from a node to the blade inlet position; l Refers to the entire arc length of the blade working surface contour; t i Refers to the first i Vertical thickening thickness at each point;

[0162] When the blade is thickened, the working surface contour can be divided into N 1 node, N 1=10~20, measure the arc length from each node to the blade inlet l i Next, take these equally divided nodes as the center of the circle and t i Draw a circle with the value as the radius, and then outline the back contour line, making sure that this contour line remains tangent to all the drawn circles, thus completing the plane geometry construction of the blade thickening design, such as Figure 5 shown.

[0163] In order to make the technical solution of the present invention clearer, a centrifugal pump impeller structure suitable for sewage treatment is designed, which is required to be able to pass solid particles with a maximum diameter d of 10 mm.

[0164] The present invention provides a method for manufacturing a centrifugal pump impeller structure, comprising the following steps:

[0165] S1. Design flow rate according to the centrifugal pump impeller structure Q = 50 m 3 / h , lift H = 20 m , speed n = 1450 rpm , calculate the specific speed of the centrifugal pump impeller structure n s ≈ 66;

[0166] S2. Determine the specific speed of the centrifugal pump impeller structure n s Finally, the pump efficiency of the centrifugal pump is preset η = 80%, volumetric efficiency η v =95%, Mechanical efficiency η m = 98%, and the theoretical head that the centrifugal pump can provide is obtained H th =23.275 m ;

[0167] S3, based on formula (3), formula (4) and K u2 =-0.711 ln ( n sth )+4.3643 to determine the impeller outlet diameter D 2;

[0168] S4. In the single-blade centrifugal pump impeller structure, the blade outlet width is preset b 2, because it needs to pass particles with a diameter of 10 mm, b 2= ​​11 mm , and then preset the blade outlet placement angle β2, based on the load factor k = 1.15 and formulas (5) to (9) to determine the relative velocity of the impeller blade outlet w 2 and relative speed of impeller blade inlet w 1;

[0169] S5. Determine the blade inlet axial speed , water absorption chamber inlet speed , blade inlet placement angle β1 and suction chamber inlet diameter D The calculation formula for obtaining 0 is (10)~(13);

[0170] S6, based on the suction port flow rate ratio K = 0.6, preset the blade inlet width b The initial value of b is 1 11 , Impeller inlet diameter D Initial value of 1 D 11 , and then substitute into formulas (3) to (12) to obtain the blade inlet axial velocity Initial value of and the initial value of the blade inlet placement angle β1 12 :

[0171] S7. Obtain the updated iterative blade inlet axial velocity , Blade inlet placement angle β 1(p+1) And blade inlet diameter D 1（p+1） ;

[0172] S8, based on iterative formula b 1（p+1） =b 1p And formula (15) for the blade inlet and outlet width b 1 is iterated to adjust the blade inlet and outlet width b 1 until the preset condition is met, and the inlet diameter of the suction chamber is obtained. D0, the final value of the blade inlet angle β1, the final value of the blade inlet width b1 and the impeller inlet diameter D 1, thereby finally determining the main parameter of the centrifugal pump impeller structure of the present invention, the inlet diameter of the suction chamber D 0. Impeller inlet diameter D 1. Impeller outlet diameter D 2. Blade inlet width b 1. Blade outlet width b 2. Blade inlet placement angle β1 and blade outlet placement angle β2; where the preset condition is b 1（p+1） -b 1p The difference is within the preset threshold range;

[0173] S9, establish a rectangular coordinate system, obtain the contour of the blade working surface, and start drawing the impeller axial projection diagram;

[0174] S10. Obtain the contour of the back side of the blade; the blade adopts a thickening method with a thick middle and thin inlet and outlet to optimize the mechanical properties and fluid dynamics characteristics of the blade, and improve the strength and durability of the blade through a specific thickening rule.

[0175] Furthermore, in order to improve the reliability of the centrifugal pump in harsh sewage treatment environments and enhance pumping efficiency, wear-resistant and corrosion-resistant materials such as stainless steel or high-chromium cast iron are selected when selecting materials for the manufacture of the centrifugal pump impeller structure; after the manufacture of the centrifugal pump impeller structure is completed, a drag-reducing coating may be applied to the front cover plate, rear cover plate and blade surface of the centrifugal pump impeller structure.

[0176] Compared with the prior art, the manufacturing method of the centrifugal pump impeller structure of the present invention has the following beneficial effects:

[0177] 1. Refined step design: The present invention adopts a more refined step design, integrating all aspects of the centrifugal pump impeller structure design, and realizes seamless connection from theoretical prediction to practical application through precise calculation and parameter optimization. The present invention overcomes the uncertainty caused by reliance on experience judgment and trial and error in the traditional centrifugal pump impeller structure design, greatly shortens the product iteration cycle, and improves the design efficiency and success rate.

[0178] 2. Introduction of load factor and suction port velocity ratio: The present invention introduces the ratio of blade outlet relative velocity to inlet relative velocity (load factor k ) and the ratio of the blade inlet axial velocity to the suction chamber inlet velocity (inlet velocity ratio K). The setting of these two key parameters helps to balance the fluid mechanics characteristics inside the impeller structure of the centrifugal pump, avoid excessive deceleration or acceleration of the fluid inside the impeller, and thus significantly improve the operating efficiency and stability of the centrifugal pump.

[0179] 3. Enhanced particle passing capacity: By optimizing the design of the number of impeller blades and the blade inlet width, the present invention successfully solves the common clogging problem of traditional centrifugal pumps when treating sewage containing large particles; specifically, by reducing the number of blades and appropriately widening the flow channel width between blades, it effectively ensures the smooth passage of particulate matter, significantly improving the application range and processing capacity of the pump.

[0180] 4. Improved efficiency and reduced energy consumption: The centrifugal pump impeller structure of the present invention utilizes the relative velocity of the blade outlet w 2 is much greater than the relative speed of the blade inlet w 1. Accelerate the flow and greatly reduce energy loss while ensuring sufficient head. Compared with the traditional design, the impeller designed in the present invention generally improves the pump efficiency by more than 20% under the same working conditions, significantly saves energy consumption, and meets the needs of green production and energy conservation and emission reduction.

[0181] In summary, the manufacturing method of a centrifugal pump impeller structure of the present invention sets at most two blades on the rear cover plate, and cooperates with the design of two key parameters: the ratio of the blade outlet relative velocity to the inlet relative velocity and the ratio of the blade inlet axial velocity to the suction chamber inlet velocity, so as to avoid excessive deceleration or acceleration of the fluid inside the impeller structure, thereby significantly improving the operating efficiency and stability of the pump.

[0182] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for manufacturing a centrifugal pump impeller structure, characterized in that: The centrifugal pump impeller structure includes a rear cover plate and at most two blades arranged on the rear cover plate, the blades are arranged on the rear cover plate in a spiral shape, one end of the blade is placed in the middle of the rear cover plate area, and the other end of the blade extends to the edge of the rear cover plate; The manufacturing method of the centrifugal pump impeller structure comprises the following steps: S1. Design flow rate according to the centrifugal pump impeller structure Q , Lift H , speed n Determining the specific speed of a centrifugal pump impeller structure n s : （1）； S2, based on the specific speed of the centrifugal pump n s , preset the pump efficiency η and volumetric efficiency of the centrifugal pump η v and mechanical efficiency η m , get the theoretical head of the centrifugal pump: （2） S3. Get the impeller outlet diameter D 2 and the theoretical specific speed of the centrifugal pump under the condition of limited number of blades n sth : （3）， （4）， Where g is the acceleration due to gravity, K u2 is the impeller outlet peripheral velocity coefficient, K u2 =-0.711 ln ( n sth )+4.3643; S4, based on the slip coefficient s and load coefficient at the impeller blade outlet k Get the relative velocity of the impeller blade outlet w 2 and relative speed of impeller blade inlet w 1: （5）， （6）， w 1= w 2 / k （7）， （8）， （9）， Among them, β2 is the blade outlet placement angle, u 2 is the circumferential speed at the blade outlet, Z is the number of impeller blades, is the impeller outlet axial velocity, is the circumferential thickness at the blade outlet, b 2 is the blade outlet width; S5. Obtain blade inlet axial velocity , water absorption chamber inlet speed , blade inlet placement angle β1 and suction chamber inlet diameter D 0: （10）， （11）， （12）， （13）， in, D 1 is the impeller inlet diameter, is the circumferential thickness at the blade inlet, b1 is the blade inlet width, and K is the suction port flow rate ratio; S6, given impeller inlet diameter D 1An initial value D 11 and the blade inlet width b1 has an initial value b 11 , and then substitute into formulas (3) to (12) to obtain the blade inlet axial velocity Initial value of and the initial value of the blade inlet placement angle β1 12 : ， ； S7, based on iterative formula , β 1(p+1) =β 1p , D 1（p+1） =D 1p 、b 1（p+1） =b 1p The initial value , , D 11 、b 11 Substitute into formulas (3) to (12) to obtain the updated blade inlet axial velocity , Blade inlet placement angle β 1(p+1) And blade inlet diameter D 1（p+1） : （14）， （15）， （16）， Where p=1, 2, 3, 4, ...; S8, based on iterative formula b 1（p+1） =b 1p And formula (15) to obtain the blade inlet width b 1（p+1） : When b 1（p+1） -b 1p When the difference is within the preset threshold, the iteration stops and the following is obtained: Suction chamber inlet diameter D The final value of 0 satisfies: ， ； The final value of the blade inlet placement angle β1 is β1=β 1(p+1) , ； The final value of the blade inlet width b1 is b1=b 1（p+1） , ； Impeller inlet diameter D The final value of 1 is D1=D 1（p+1） , 。 2. The method for manufacturing a centrifugal pump impeller structure according to claim 1, characterized in that: It also includes the following steps, S9. Establish a rectangular coordinate system to obtain the contour of the blade working surface: r=D1 ·e λ / 2,x=r·cos(T·360),y=r·sin(T·360); The blade working surface is the side surface corresponding to the arc-shaped convex side of the blade, e=2.71828, λ=2πT×(m1 · (360T / θ) M +tanβ1), , , , θ is the blade wrap angle, θ =150°~300°; in the rectangular coordinate system, r, x, and y refer to the polar radius, the coordinate value of the x-axis, and the coordinate value of the y-axis, respectively.

3. The method for manufacturing a centrifugal pump impeller structure according to claim 2, characterized in that: It also includes the following steps, S10, obtaining the contour of the back side of the blade; wherein the method for obtaining the contour of the back side of the blade is: Get the maximum thickness of the leaf ; The thickening rule of the blade along the working surface of the blade meets the following requirements: ， in, l i Refers to the first i The length of the arc from a node to the blade inlet position; l Refers to the entire arc length of the blade working surface contour; t i Refers to the first i The thickness is increased vertically at each point.

4. The method for manufacturing a centrifugal pump impeller structure according to claim 3, characterized in that: The method for obtaining the contour of the back side of the blade further includes: When the blade is thickened, the working surface contour can be divided into N 1 node, N 1=10~20, measure the arc length from each node to the blade inlet l i , with the equally divided node as the center, and its corresponding t i Draw a circle with the value as the radius, outlining the back face outline, which remains tangent to all the drawn circles.

5. The method for manufacturing a centrifugal pump impeller structure according to claim 1, characterized in that: In step S3, the theoretical specific speed of the centrifugal pump under the condition of a limited number of blades is obtained. n sth The method is: Theoretical head of centrifugal pump H th Replace the lift of centrifugal pump H , substituting into formula (1), the theoretical specific speed of the centrifugal pump under the condition of limited number of blades is obtained n sth : （4）。 6. The method for manufacturing a centrifugal pump impeller structure according to claim 1, characterized in that: Said b The value of 2 must satisfy b 2=(1~1.1) d , the initial value b of the blade inlet width b1 11 Satisfy b 11 = (1.1~1.2) d , the blade outlet placement angle β2 = 15°~35°.

7. The method for manufacturing a centrifugal pump impeller structure according to claim 1, characterized in that: The load factor k =1.1~1.8, the suction port flow rate ratio K=0.3~0.

8.

8. The method for manufacturing a centrifugal pump impeller structure according to claim 1, characterized in that: The number of impeller blades is Z = 1 or Z = 2.

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