Pump core design method and multistage pump

Abstract

The application relates to a pump core design method and a multistage pump, and relates to the technical field of the multistage pump.The pump core design method comprises an impeller, the impeller comprises a front cover plate, blades and a rear cover plate, and the diameter of the rear cover plate is smaller than that of the front cover plate.The application has the advantages of high efficiency.

Description

Technical Field

[0001] This application relates to the technical field of multistage pumps, and in particular to a pump core design method and a multistage pump. Background Technology

[0002] A multistage pump is a centrifugal pump that achieves high head by using multiple impellers connected in series. Multistage pumps are commonly used in energy storage to boost the pressure of circulating cooling systems. Traditional multistage pumps are complex in structure, large in size, and inefficient. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, one of the purposes of this application is to provide a pump core design method and a multi-stage pump, which has the advantage of high efficiency.

[0004] The above-mentioned objective of this application is achieved through the following technical solution: This application discloses a pump core design method, including the following steps: S1: Calculate the reference velocity at the impeller inlet. ; S2: Calculate the axial outflow rate when the diameter of the rear cover plate is smaller than that of the front cover plate. ; S3: Based on the axial outflow rate after cutting Calculate its outflow velocity ; S4: Determine the axial length using the interstage axial length calculation formula. .

[0005] In a preferred embodiment, this application can be further configured such that, in step S1, Among them, the rated flow rate of multistage pumps Unit: m 3 / h, inlet diameter , Unit: mm.

[0006] In a preferred embodiment, this application can be further configured such that, in step S2, The diameter of the front cover is Unit: mm The diameter of the rear cover is in mm. The distance between the inner sides of the front and rear cover plates of the impeller is in mm.

[0007] In a preferred embodiment, this application can be further configured such that, in step S3... The diameter of the front cover is Unit: mm The diameter of the rear cover is in mm.

[0008] In a preferred embodiment, this application can be further configured such that, in step S4... ,in, The distance between the inner sides of the impeller's front and rear cover plates, in mm. This is the coefficient for calculating axial length, with a value range of 1-3.

[0009] This application also discloses a multistage pump, which uses the pump core design method described above to obtain the pump core.

[0010] This application has the following advantages: Efficiency is improved by reducing the diameter of the impeller's rear cover plate and designing the interstage axial length accordingly. In this multistage pump application, to reduce the diameter, forward guide vanes are not used. Previously, fluid exiting the impeller directly impacted the pump casing radially before entering the reverse guide vanes, resulting in significant impact losses. By making the diameter of the impeller's rear cover plate smaller than the front cover plate, a portion of the fluid passes through the reduced section and enters the reverse guide vanes axially, reducing impact losses. Furthermore, by controlling the axial length, the fluid distribution is made more uniform, further reducing losses entering the reverse guide vanes. Attached Figure Description

[0011] Figure 1 This is a cross-sectional structural diagram of this application.

[0012] Figure 2 This is a schematic diagram of the impeller structure of this application.

[0013] Diagram markings: 1. Front cover; 2. Rear cover. Detailed Implementation

[0014] The present application will be further described in detail below with reference to the accompanying drawings.

[0015] Reference Figure 1 and Figure 2 This application discloses a pump core design method, in which the front cover plate 1 and the rear cover plate 2 have the same diameter. For ease of description, the method is exemplified by obtaining the dimensions of the rear cover plate 2 after cutting and trimming. The method includes the following steps: S1: Calculate the reference velocity at the impeller inlet. ; S2: Calculate the axial outflow rate when the diameter of the rear cover plate 2 is smaller than the diameter of the front cover plate 1. ; S3: Based on the axial outflow rate after cutting Calculate its outflow velocity ; S4: Determine the axial length using the interstage axial length calculation formula. (The axial length L is only related to the size of the corresponding impeller's rear cover plate 2).

[0016] More specific S1: Calculate the reference velocity at the impeller inlet using the fluid dynamics velocity calculation formula. As shown in formula (1): (1) S2: The outflow area is used to distribute the flow rate, and the axial outflow rate after the rear cover plate 2 is cut is calculated. As shown in formulas (2) and (3): (2) (3) In the formula: d is the radial length of the cut, in mm, and the diameter of the front cover plate is... Unit: mm The diameter of the cut impeller back cover plate is 2, in units of ; The distance between the inner sides of the impeller's front and rear cover plates, in units of... .

[0017] S3: Based on the axial outflow rate after cutting Its outflow velocity can be calculated. As shown in formula (4): (4) S4: The axial length can be calculated and determined by combining the interstage axial length calculation formula. As shown in formula (5): (5) In the formula: This is a coefficient for calculating axial length. If the pump length requirement is short, take [value missing]. If high pump efficiency is required, choose... If low pump vibration and noise are required, choose... .

[0018] Taking a multistage pump as an example, the rated flow rate of a multistage pump is known. Inlet diameter Impeller rear cover plate 2 diameter Rear cover plate 2 cutting length The distance between the inner sides of the front and rear cover plates 2 of the impeller .

[0019] S1: Calculate the reference velocity at the impeller inlet using the fluid dynamics velocity calculation formula. As shown in formula (1): (1) S2: The outflow area is used to distribute the flow rate, and the axial outflow rate after the rear cover plate 2 is cut is calculated. As shown in formulas (2) and (3): (2) (3) In the formula: d is the radial length of the cut, in mm, and the diameter of the front cover plate is... , The diameter of the cut impeller back cover plate is 2, in units of ; The distance between the inner sides of the front and rear cover plates 2 of the impeller, in units of .

[0020] S3: Based on the axial outflow rate after cutting Its outflow velocity can be calculated. As shown in formula (4): (4) S4: The axial length can be calculated and determined by combining the interstage axial length calculation formula. As shown in formula (5): (5) In the formula: This is a coefficient for calculating axial length. If the pump length requirement is short, take [value missing]. If high pump efficiency is required, choose... If low pump vibration and noise are required, choose... Select Finally, based on the above calculations, the interstage axial length of the multi-stage pump is obtained. .

[0021] This application also discloses a multistage pump, which uses the pump core described above or a pump core design method described above. When the multistage pump uses the pump core described above or a pump core obtained by the design method described above, the diameter of the rear cover plate of one or more impellers in the pump core is smaller than the diameter of the corresponding front cover plate.

[0022] The implementation principle of this embodiment is as follows: by reducing the diameter of the impeller rear cover plate 2 and designing the interstage axial length according to the diameter reduction, the efficiency can be improved.

[0023] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for designing a pump core, characterized in that: Includes the following steps: S1: Calculate the reference velocity at the impeller inlet. ; S2: Calculate the axial outflow rate when the diameter of the rear cover plate is smaller than that of the front cover plate. ; S3: Based on axial outflow rate Calculate the outflow velocity of the impeller. ; S4: Determine the interstage axial length using the interstage axial length calculation formula. .

2. The pump core design method according to claim 1, characterized in that: In step S1, Among them, the rated flow rate of multistage pumps Unit: m 3 / h, the impeller inlet diameter , Unit: mm.

3. The pump core and its design method according to claim 4, characterized in that: In step S2, The diameter of the front cover is Unit: mm The diameter of the rear cover is in mm. The distance between the inner sides of the front and rear cover plates of the impeller is in mm.

4. The pump core design method according to claim 1, characterized in that: In step S3, The diameter of the front cover is Unit: mm The diameter of the rear cover is in mm.

5. The pump core design method according to claim 1, characterized in that: In step S4, ,in, The distance between the inner sides of the impeller's front and rear cover plates, in mm. This is the coefficient for calculating axial length, with a value range of 1-3.

6. A multistage pump, characterized in that: A pump core obtained by using a pump core design method as described in any one of claims 1-5.

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