Pipeline type pump unit, pumping chamber of pipeline type pump unit and flow channel design method of pumping chamber

Abstract

The invention discloses a pipeline type pump unit, a pumping chamber of the pipeline type pump unit and a flow channel design method of the pumping chamber and belongs to the field of pump units. According to the flow channel design, the base circle design and the spiral pumping chamber inlet width are increased on the basis of the traditional design, and the gap between the impeller and the pumping chamber is enlarged, so that the strength of dynamic and static interference between the impeller and the pumping chamber can be effectively reduced in the running process of the pump, and the service life of the pump is prolonged. Pressure pulsation generated on the outlet side of an impeller blade due to dynamic and static interference in the pump operation process is reduced, so that flow-induced noise is reduced, and flow loss is reduced; meanwhile, the gap between the impeller and the pumping chamber is enlarged, the allowable error is increased, and the problem of interference between the impeller and a flow channel of the pumping chamber caused by machining and manufacturing errors and the like can be avoided; and on the premise that the performance is met, impellers with different widths and radiuses corresponding to different flow requirements can be compatible, so that the product is platformized, and the universality of the product is improved.

Description

Technical Field

[0001] This invention relates to the field of pump unit flow channel design technology, and more specifically, to a pipeline pump unit and its pressure chamber and flow channel design method. Background Technology

[0002] In the field of pump units, the spiral condenser is widely used in various types of pumps, such as centrifugal pumps and mixed-flow pumps, due to its ideal flow, strong adaptability, and wide high-efficiency range. As a core hydraulic component, the rationality of its flow channel structure directly determines the pump's efficiency, operational stability, and noise level. The design methodology for spiral condensers has undergone many years of development and has now formed a classic hydraulic theory design system, which is widely adopted in the industry. However, while the traditional design of spiral condensers simplifies the design process, its main focus is on meeting hydraulic performance requirements. It also presents some challenges in terms of process sensitivity, noise issues, and versatility, posing greater challenges for researchers.

[0003] A search revealed new design approaches for the spiral compression chamber of pumps. For example, patent CN103994102A discloses a design method for a spiral compression chamber in a low specific speed centrifugal pump, optimizing the geometric parameters of the spiral compression chamber to achieve higher hydraulic efficiency and stability, expand the operating flow range, and reduce vibration and noise. Patent CN113464495A provides a spiral compression chamber for multi-stage pumps that automatically balances radial forces and its design method. By designing symmetrical spiral compression chambers in a multi-stage pump, symmetrically arranged baffles and diffusers generate counteracting radial forces on the impeller, solving the vibration problem caused by radial forces in existing technologies and improving pump efficiency and lifespan. Patent CN113530887A provides a spiral compression chamber structure for centrifugal pumps. By adjusting the expansion angle and the helix conservation coefficient, it solves the efficiency reduction problem of centrifugal pumps with a large flow adjustment range, achieving higher efficiency and stability. It is evident that, in order to improve the performance of pumps in various aspects, the industry has generally paid attention to the necessity of further optimizing the traditional flow channel design, and the design of the pressure chamber flow channel has always been a hot topic of concern in the industry. Summary of the Invention

[0004] 1. The technical problem that the invention aims to solve The purpose of this invention is to provide a pipeline pump unit and its pressure chamber and flow channel design method. By optimizing the flow channel design, the pump unit performance can be further improved, and the pump unit can be made more noise-efficient, efficient and versatile.

[0005] 2. Technical Solution To achieve the above objectives, the technical solution provided by the present invention is as follows: This invention discloses a design method for the flow channel of a pipeline pump unit's pressure chamber. The pump body has an impeller and forms a spiral pressure chamber. The key dimensions of the pressure chamber include: the base circle D3 of the spiral pressure chamber, the inlet width b3 of the pressure chamber flow channel, and the third... Cross-sectional area ; in: ; The impeller outer diameter is in mm. ; The impeller outlet width is in mm. The flow area of ​​the 8th section in the pressure chamber satisfy:

[0006]

[0007] in, The average velocity of the vortex chamber cross section is , in m / s; For design flow rate, m 3 / s; The flow area of ​​section 8 is in mm. 2 ; H The head of the pump is in meters (m). The velocity coefficient is selected based on the Stepanov curve; g is the acceleration due to gravity, m / s² 2 ; Flow area of ​​other sections in the pressure chamber satisfy:

[0008] in, The section number is a positive integer from 1 to 7; For the first The cross-sectional area coefficient, where The value is between 0.135 and 0.175. The value is 0.3~0.35. The value is between 0.425 and 0.475. The value is 0.55~0.6. The value is between 0.635 and 0.675. It is 0.76~0.8. The value is 0.885~0.925.

[0009] The present invention also provides a pressure chamber for a pipeline pump unit, wherein the flow channel adopts the design method described above.

[0010] The present invention also provides a pipeline pump unit having a pressure chamber as described above.

[0011] 3. Beneficial effects Compared with the prior art, the technical solution provided by this invention has the following advantages: (1) The flow channel design of the present invention increases the base circle design and the inlet width of the spiral pressure chamber on the basis of the traditional design, and expands the gap between the impeller and the pressure chamber. Therefore, during the operation of the pump, the intensity of dynamic and static interference between the impeller and the pressure chamber can be effectively reduced, and the pressure pulsation generated on the outlet side of the impeller blade due to dynamic and static interference during the operation of the pump can be reduced, thereby reducing flow-induced noise and reducing flow loss. At the same time, the increased gap between the impeller and the pressure chamber increases the allowable error, which can avoid the interference problem between the impeller and the pressure chamber flow channel caused by manufacturing errors, etc. It can also be compatible with impellers of different widths and radii corresponding to different flow requirements while meeting the performance requirements, making the product platform and improving the versatility of the product.

[0012] (2) The flow channel design of the present invention increases the cross-sectional area of ​​the eight sections of the condenser chamber to different degrees on the basis of the traditional design, changes the flow velocity distribution in the condenser chamber, reduces the high turbulent kinetic energy region of the fluid in the middle section of the condenser chamber, reduces flow separation or eddies caused by excessive flow velocity, and thus reduces hydraulic loss; after the flow velocity in the middle section is reduced, the kinetic energy of the fluid when it reaches the tongue is weakened, reducing the impact force on the tongue and the flow-induced noise caused by local impact, thereby extending the life of the tongue and reducing hydraulic noise; the pressure gradient distribution in the condenser chamber is adjusted to partially offset the asymmetrical pressure at the impeller outlet and reduce the radial force caused by the pressure asymmetry near the tongue of the spiral condenser chamber. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the pump unit in the embodiment; Figure 2 This is a schematic diagram of the cross-sectional distribution of the pressure chamber flow channel in the embodiment; Figure 3 This is a schematic diagram of the impeller structure in the embodiment; Figure 4 This is a schematic diagram showing the angle distribution of each cross-section of the flow channel in the pressure chamber in the embodiment; Figure 5 This is a schematic diagram showing the location distribution for monitoring pressure pulsation values ​​in the pressure chamber in this embodiment. Figure 6 for Figure 5 A schematic diagram of the noise verification results at monitoring point P1 in the middle; Figure 7 for Figure 5 A schematic diagram of the noise verification results at monitoring point P2 in the middle; Figure 8 for Figure 5 A schematic diagram of the noise verification results at monitoring point P3 in the middle; Figure 9 for Figure 5 A schematic diagram of the noise verification results at monitoring point P4.

[0014] Explanation of the labels in the diagram: 100, Pump body; 200, Impeller; 300, Pressure chamber. Detailed Implementation

[0015] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0016] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] The present invention will be further described below with reference to embodiments.

[0018] Example Combination Figures 1-4 As shown, to more fully understand the solution of this embodiment, the traditional design scheme of the spiral pressure chamber in the industry will be described first. The pump unit includes a pump body 100, within which an impeller 200 is located, forming a spiral pressure chamber 300. The key dimension of the pressure chamber 300 includes the base circle of the spiral pressure chamber 300. The inlet width of the 300mm flow channel in the pressure chamber and the cross-sectional area of ​​the flow channel In this invention, the flow area of ​​the 8th cross section is used. The size of the flow channel cross-sectional area is used to characterize the flow channel. The base circle is the circle tangent to the starting point of the spiral line of the spiral pressure chamber 300; the inlet width of the pressure chamber 300 is the width of the flow channel, i.e., the transverse dimension of the flow channel perpendicular to the flow direction. The first one in the plan view of the pressure chamber 300 The cross-sectional area of ​​the flow path; For the first The cross-sectional position angle of a section is defined. These represent the starting and ending points of the cross-sectional position angles, i.e., 0° and 360°. The cross-sectional position angle for the first cross-section is 45°, for the second cross-section it is 90°, and so on. The parameters are as follows: Figure 1 and Figure 2 As shown.

[0019] The traditional spiral pressure chamber design in the industry is mainly based on the following design scheme: Base circle size Typically, the impeller outer diameter is 200 mm. 1.03 to 1.08 times, that is: .

[0020] 300mm inlet width of pressure chamber In traditional design, Typically, the impeller outlet width is 200 mm. 1.6 to 2 times, that is: .

[0021] Cross-sectional area distribution: Area of ​​section 8 Calculated using the velocity coefficient method, based on the principle of equal velocity, the cross-sectional areas are distributed proportionally according to the angle, i.e., the flow area of ​​the 8th cross-section in the 300 plan view of the spiral plenum chamber. satisfy:

[0022]

[0023] in, The average velocity of the vortex chamber cross section is expressed in m / s. H represents the pump's single-stage head, in meters (m). This is the velocity coefficient, the value of which can be selected based on the Stepanov curve; g is the acceleration due to gravity, m / s² 2 ;

[0024] in, The serial number is a positive integer from 1 to 7; The first one in the plan view of the pressure chamber 300 The cross-sectional area of ​​the flow path, in mm² 2 ; For the first The cross-sectional position angle of a section is defined. Let 0° and 360° be the starting and ending points of the cross-sectional position angles. Then, the cross-sectional position angle of the first cross-section is 45°, the cross-sectional position angle of the second cross-section is 90°, and so on. Figure 1 and Figure 2 As shown.

[0025] The traditional design approach, which focuses on meeting hydraulic performance requirements, simplifies the design process. However, through long-term practice, the applicant has found that this design still results in significant drawbacks for the pump body in terms of process sensitivity, noise levels, and versatility. These are specifically manifested as follows: First, the base circle With import width The design is sensitive to manufacturing errors. The design is too compact, resulting in a very small gap between the impeller 200 and the pressure chamber 300. If the outer diameter or outlet width of the impeller 200 is too large during casting or machining, it is very easy to cause friction between the impeller 200 and the pump body 100. Considering the amplification effect of dynamic and static interference in high-speed canned pumps, the small base circle diameter exacerbates the intensity of dynamic and static interference, resulting in a higher pressure pulsation amplitude and causing vibration and noise pollution.

[0026] Secondly, the traditional design adopts a "one pump, one pressure chamber" model. The parameter ratios in this traditional design limit the adaptability range, failing to cover the varying outer diameters and outlet widths of the impeller 200. This lack of versatility makes it difficult to adapt to impeller 200s with different flow rate requirements within the same series, resulting in high development costs and long development cycles. Due to the dynamic diffusion characteristics of fluid in a spiral flow channel, the area gradient of the first few cross-sections is large, easily forming flow separation zones and vortices in the first half of the flow channel. Due to structural asymmetry, high-pressure pulsations are easily generated near the impeller 200, leading to significant radial forces, which in turn cause vibration and noise, affecting the stable operation of the pump. Furthermore, the impeller area is prone to vortices due to sudden changes in flow regime, resulting in severe localized wear.

[0027] To address the above issues, this invention proposes a novel design scheme for the flow channel of the pressure chamber in a pipeline pump unit, which involves modifying the base circle... Redundant design and inlet width The extended design increases the gap between the impeller 200 and the pressure chamber 300 while meeting hydraulic performance requirements, increasing the allowable casting and machining tolerances. This gives the invention the characteristics of good manufacturing process and high tolerance to casting or machining errors, greatly reducing the risk of interference friction caused by manufacturing process, manufacturing errors and assembly deviations in the water pump.

[0028] Secondly, the spiral pressure chamber pump body designed by the method proposed in this invention has a larger base circle and inlet width compared to the pump body designed by the traditional spiral pressure chamber. Therefore, it has good compatibility with impellers 200 with different outer diameters and widths, high versatility, and greatly reduces the types of pump bodies for serialized product development, thereby reducing development costs.

[0029] Finally, traditional spiral compression chambers calculate the cross-sectional area of ​​each section based on the principle of equal velocity using the velocity coefficient method. While this method simplifies the design process, it does not consider the dynamic diffusion characteristics of the fluid in the spiral channel. For example, the large area gradient in the first few sections leads to a sudden drop in flow velocity, easily forming a flow separation zone in the first half of the channel. In contrast, the spiral compression chamber 300 in this invention adopts a large flow area design, adjusting the area of ​​each section to different degrees. By optimizing the area gradient of each section, flow separation and impact losses are reduced, resulting in characteristics such as low outlet velocity, low pressure pulsation, and small radial force.

[0030] As can be seen, the flow channel design scheme of the present invention can systematically solve multi-objective conflicts. By coordinating the adjustment of the base circle, inlet width, and cross-sectional area, it can simultaneously achieve low noise, high efficiency, and high versatility, and effectively balance the impact of base circle diameter expansion on efficiency, excessive gap leading to leakage loss, the impact of inlet width expansion on velocity distribution, and the effect of cross-sectional area gradient on turbulence suppression.

[0031] Taking an energy-saving canned motor pump as an example, the design scheme of this invention is described in detail below: The basic parameters of the canned motor pump in this case are: Design flow =2m 3 The design head is H=5.3m, and the design speed is 5300rpm. The existing impeller dimensions are: outer diameter 200. The outlet width of the impeller is 38.5mm, and the diameter is 200mm. The diameter is 3.2mm, and the pressure chamber 300 is designed based on this.

[0032] The design formulas for the key dimensions of the spiral pressure chamber 300 are as follows: S1. Based on the traditional pressure chamber design method, a redundant base circle design is implemented, increasing the gap between the impeller 200 and the pressure chamber 300. Location and comments Figure 1 and Figure 2 It satisfies:

[0033] in, The impeller outer diameter is in mm.

[0034] In this embodiment, specifically take In practice, it can also be adopted. , , , , wait.

[0035] S2. Based on the traditional pressure chamber design method, increase the inlet width of the pressure chamber by 300mm. Location and comments Figure 1 It satisfies:

[0036] in, This refers to the impeller outlet width, in mm.

[0037] In this embodiment, the coefficient is taken as 3.75, and the calculation is as follows: In practice, it can also be adopted. , , , .

[0038] S3. The flow area of ​​section 8 in the plan view of the spiral plenum chamber is calculated using the traditional method. satisfy:

[0039]

[0040] in, The average velocity of the vortex chamber cross section is expressed in m / s. The design flow rate is expressed in cubic meters (m³). 3 / s; This is the flow area of ​​section 8; H represents the pump's single-stage head, in meters (m). g is the acceleration due to gravity, m / s² 2 ; This is the velocity coefficient, the value of which can be selected based on the Stepanov curve.

[0041] In this embodiment, the spiral-shaped pressure chamber adopts a rounded rectangular cross-section, see... Figure 1 Selected based on Stepanov curve Calculated .

[0042] S4. The area of ​​other cross-sections shall be calculated according to the following formula:

[0043] in, The serial number is a positive integer from 1 to 7; The first one in the plan of the pressure chamber The cross-sectional area of ​​the flow path, in mm² 2 ; The first one in the plan of the pressure chamber Cross-sectional flow area coefficient.

[0044] Traditional pressure chamber design methods in the industry follow the principle of equal velocity, distributing the cross-sectional area according to angle proportions, i.e., the coefficient is: 0.125, 0.25 0.375 0.5 0.625 0.75 It is 0.875; Compared to the cross-sectional area obtained by traditional methods, this invention adjusts... The numerical values ​​are optimized for the flow area of ​​other cross-sections, increasing the flow area of ​​each cross-section to varying degrees. Specifically, in this embodiment, the flow area coefficient of the pressure chamber cross-section is... The values ​​differ from those of traditional design methods as follows: The value is between 0.135 and 0.175, and in practice, specific values ​​such as 0.135, 0.145, 0.15, 0.155, 0.16, 0.165, 0.17, and 0.175 can be used. The value is 0.3~0.35, and in practice, specific values ​​such as 0.3, 0.32, 0.33, and 0.35 can be used. The value is between 0.425 and 0.475, and in practice, specific values ​​such as 0.425, 0.435, 0.445, 0.455, 0.465, and 0.475 can be used. The value is 0.55~0.6, and in practice, specific values ​​such as 0.55, 0.56, 0.58, and 0.6 can be used. The value is 0.635~0.675, and in practice, specific values ​​such as 0.635, 0.645, 0.65, 0.655, 0.66, 0.67, and 0.675 can be used. The value is 0.76~0.8, and in practice, specific values ​​such as 0.76, 0.78, and 0.8 can be used. The value is 0.885~0.925, and in practice, specific values ​​such as 0.885, 0.895, 0.9, 0.915, 0.92, and 0.925 can be used.

[0045] For comparative verification, the design of pressure chamber A was based on the traditional pressure chamber design scheme in the industry, and the following was adopted. , The cross-sectional area is distributed according to the principle of equal velocity, and the area of ​​each cross-section is proportional to the angle, i.e., the coefficient. 0.125, 0.25 0.375 0.5 0.625 0.75 It is 0.875.

[0046] The pressure chambers B, C, and D are designed based on the design scheme of this invention. Pressure chamber B is selected according to the lower limit of the coefficient. , Cross-sectional area according to coefficient 0.135 0.3 0.425 0.55 0.635 0.76 The value is allocated to 0.885; the pressure chamber C is taken according to the upper limit of the coefficient. , Cross-sectional area according to coefficient 0.175 0.35 0.475 0.6 It is 0.675. 0.8 The allocation is 0.925; the pressure chamber D is taken as... , Cross-sectional area according to coefficient 0.145 0.32 0.43 0.57 0.65 0.78 It is allocated to 0.9.

[0047] Simulation comparison and verification were performed, and the noise verification results are as follows: Figure 4 As shown. Among them Figure 3 Table 1 shows the locations of pressure pulsation monitoring points P1, P2, P3, and P4. The maximum turbulent kinetic energy of the pressure chamber at the design point for schemes A, B, C, and D is shown in Table 1.

[0048] Table 1 Comparison of Maximum Turbulent Kinetic Energy for Each Scheme

[0049] It is evident that the flow channel design scheme of the present invention has lower pressure pulsation value, smaller turbulent kinetic energy and higher process tolerance, which has outstanding practical significance.

[0050] The present invention and its embodiments have been described above illustratively. This description is not restrictive and is merely one embodiment of the present invention, and is not actually limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for designing the flow channel of the pressure chamber of a pipeline pump unit, characterized in that, The pump body (100) has an impeller (200) and forms a spiral pressure chamber (300). The key dimensions of the pressure chamber (300) include: the base circle D3 of the spiral pressure chamber (300), the inlet width b3 of the flow channel of the pressure chamber (300), and the third... Cross-sectional area ; in: ; The outer diameter of the impeller (200) is in mm; ; The impeller outlet width is in mm. The flow area of ​​the 8th section in the pressure chamber (300) satisfy: in, is the average velocity of the vortex chamber cross section, in m / s; For design flow rate, m 3 / s; The flow area of ​​section 8 is in mm. 2 ; H The head of the pump is measured in meters (m). The velocity coefficient is selected based on the Stepanov curve; g is the acceleration due to gravity, m / s² 2 ; Flow area of ​​other sections in the pressure chamber (300) satisfy: in, The section number is a positive integer from 1 to 7; For the first Cross-sectional area coefficient; where The value is between 0.135 and 0.

175. The value is 0.3~0.

35. The value is between 0.425 and 0.

475. The value is 0.55~0.

6. The value is between 0.635 and 0.

675. It is 0.76~0.

8. The value is 0.885~0.

925.

2. A pressure chamber for a pipeline pump unit, characterized in that: The flow channel of the pressure chamber (300) adopts the design method described in claim 1.

3. A pipeline pump unit, characterized in that: It has a pressure chamber (300) as described in claim 2.

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