A pump core, a multi-stage pump and a design method thereof

Abstract

This application relates to a pump core, a multistage pump, and a design method thereof, specifically to the technical field of multistage pumps. The impeller includes a front cover plate, blades, and a rear cover plate, with the diameter of the rear cover plate being smaller than that of the front cover plate. This application offers the advantage of higher efficiency.

Description

Technical Field

[0001] This application relates to the technical field of multistage pumps, and in particular to a pump core, a multistage pump, and a design method thereof. 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, a multistage pump and its design method, which has the advantage of high efficiency.

[0004] The above-mentioned objective of this application is achieved through the following technical solution:

[0005] A pump core includes an impeller, the impeller comprising a front cover plate, blades, and a rear cover plate, the diameter of the rear cover plate being smaller than the diameter of the front cover plate.

[0006] In a preferred embodiment, this application can be further configured such that the diameter of the rear cover / the diameter of the front cover = 0.8~0.99.

[0007] In a preferred embodiment, this application can be further configured such that the interstage axial length of adjacent impellers is... , , , , ,in, The distance between the inner sides of the impeller's front and rear cover plates, in mm. This is a coefficient for calculating axial length, with a value ranging from 1 to 3. The rated flow rate of the multistage pump is... Unit: m 3 / h, the impeller inlet diameter Unit: mm, front cover diameter is Unit: mm The diameter of the rear cover is in mm.

[0008] This application also discloses a pump core design method, comprising the following steps:

[0009] S1: Calculate the reference velocity at the impeller inlet. ;

[0010] S2: Calculate the axial outflow rate when the diameter of the rear cover plate is smaller than that of the front cover plate. ;

[0011] S3: Based on the axial outflow rate after cutting Calculate its outflow velocity ;

[0012] S4: Determine the axial length using the interstage axial length calculation formula. .

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] This application also discloses a multistage pump, which uses the pump core described above or a pump core design method described above.

[0018] This application has the following advantages:

[0019] 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

[0020] Figure 1 This is a cross-sectional structural diagram of this application.

[0021] Figure 2 This is a schematic diagram of the impeller structure of this application.

[0022] Diagram markings: 1. Front cover; 2. Rear cover. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the accompanying drawings.

[0024] Reference Figure 1 and Figure 2 This application discloses a pump core comprising an impeller, which includes a front cover plate 1, blades, and a rear cover plate 2. The diameter of the rear cover plate 2 is smaller than the diameter of the front cover plate 1, and the ratio of the diameter of the rear cover plate to the diameter of the front cover plate is 0.8 to 0.99. There can be multiple impellers, and the diameter of the rear cover plate 2 of one or more impellers can be smaller than the diameter of its corresponding front cover plate 1. The difference between the diameter of the rear cover plate 2 of each impeller and the diameter of its corresponding front cover plate 1 can be the same or different. For example, the diameter of the rear cover plate 2 of the first impeller is 0.1 unit length smaller than the diameter of its corresponding front cover plate 1, the diameter of the rear cover plate 2 of the second impeller is 0.2 unit length smaller than the diameter of its corresponding front cover plate 1, or the diameter of the rear cover plate 2 of each impeller is the same unit length smaller than the diameter of its corresponding front cover plate 1.

[0025] The interstage axial length of adjacent impellers is , , , , ,in, The distance between the inner sides of the impeller's front and rear cover plates, in mm. This is a coefficient for calculating axial length, with a value ranging from 1 to 3. The rated flow rate of the multistage pump is... Unit: m 3 / h, the impeller inlet diameter Unit: mm, front cover diameter is Unit: mm The diameter of the rear cover is in mm.

[0026] This application also 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:

[0027] S1: Calculate the reference velocity at the impeller inlet. ;

[0028] 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. ;

[0029] S3: Based on the axial outflow rate after cutting Calculate its outflow velocity ;

[0030] 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).

[0031] More specific

[0032] S1: Calculate the reference velocity at the impeller inlet using the fluid dynamics velocity calculation formula. As shown in formula (1):

[0033] (1)

[0034] 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):

[0035] (2)

[0036] (3)

[0037] 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... .

[0038] S3: Based on the axial outflow rate after cutting Its outflow velocity can be calculated. As shown in formula (4):

[0039] (4)

[0040] S4: The axial length can be calculated and determined by combining the interstage axial length calculation formula. As shown in formula (5):

[0041] (5)

[0042] 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... .

[0043] 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 .

[0044] S1: Calculate the reference velocity at the impeller inlet using the fluid dynamics velocity calculation formula. As shown in formula (1):

[0045] (1)

[0046] 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):

[0047] (2)

[0048] (3)

[0049] 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 .

[0050] S3: Based on the axial outflow rate after cutting Its outflow velocity can be calculated. As shown in formula (4):

[0051] (4)

[0052] S4: The axial length can be calculated and determined by combining the interstage axial length calculation formula. As shown in formula (5):

[0053] (5)

[0054] 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. .

[0055] 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.

[0056] 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.

[0057] 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 pump core, characterized in that: The impeller includes a front cover plate, blades, and a rear cover plate, the diameter of which is smaller than that of the front cover plate; the interstage axial length of adjacent impellers is... , , ， ， ， in, The distance between the inner sides of the impeller's front and rear cover plates, in mm. This is a coefficient for calculating axial length, with a value ranging from 1 to 3. The rated flow rate of the multistage pump is... Unit: m 3 / h, the impeller inlet diameter Unit: mm, front cover diameter is Unit: mm The diameter of the rear cover is in mm. The reference velocity at the impeller inlet is expressed in m / s. Axial outflow rate after cutting The outflow velocity, in m / s.

2. A pump core according to claim 1, characterized in that: The ratio of the diameter of the rear cover to the diameter of the front cover is 0.8 to 0.

99.

3. A multi-stage pump, characterized in that: The pump core described in any one of claims 1-2 is used.

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