A pump water pressure chamber and design method

Abstract

This application discloses a pump pressure water chamber and a design method, which relates to the technical field of water pumps and includes a volute. A cavity is provided on the inner wall surface of the volute. There are N cavities, and the interval angle between adjacent cavities is. This application has the advantage of being able to reduce the vibration and noise generated by the water pump during operation.

Description

Technical Field

[0001] This application relates to the technical field of water pumps, and in particular to a pump pressure water chamber and a design method thereof. Background Art

[0002] When the existing pump body operates, during the rotation of the impeller, the pressure pulsation caused by the dynamic and static interference between the rotating impeller and the stationary volute wall surface will cause the phenomenon of vibration and noise during the operation of the water pump. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, one of the purposes of this application is to provide a pump pressure water chamber and a design method thereof, which have the advantage of being able to reduce the vibration and noise generated during the operation of the water pump.

[0004] The above object of this application is achieved through the following technical solutions:

[0005] This application discloses a pump pressure water chamber, including a volute. A cavity is provided on the inner wall surface of the volute. There are N cavities, and the interval angle between adjacent cavities is .

[0006] In a preferred example of this application, it can be further configured that: a partition is provided in the cavity, and the material strength of the partition is not less than that of the volute.

[0007] In a preferred example of this application, it can be further configured that: the structure of the cavity is a polyhedron, a sphere or a hemisphere.

[0008] This application also discloses a design method for a pump pressure water chamber for designing the above pump pressure water chamber: including the following steps, the step of obtaining the pressure on the inner wall surface of the volute, obtaining the pressure value p per unit area acting on the wall surface of the centrifugal pump volute, the step of calculating the inlet area of the cavity, and the inlet area of the cavity satisfies the formula, , where p is the pressure value per unit area acting on the wall surface of the centrifugal pump volute, with the unit of N / m 2 ; A is the inlet area of the cavity, with the unit of m 2 ; is the liquid surface tension, with the unit of N / m; L is the perimeter length of the cavity opening, with the unit of m, the step of calculating the volume of the cavity, and the volume of the cavity satisfies the formula, , where V is the volume of the cavity structure, with the unit of m 3 ; A is the inlet area of the cavity structure, with the unit of m 2 ; b is the depth of the cavity structure in the direction of the volute wall thickness, with the unit of m.

[0009] In a preferred example of this application, it can be further configured that: , where H is the designed head of the centrifugal pump, with the unit of m; ρ is the liquid density, with the unit of kg / m 3 ; g is the acceleration due to gravity, with the unit of m / s 2 . C is the pulsation coefficient, taking values from 1.5 to 5.

[0010] In a preferred example of the present application, it can be further configured as follows: it further includes a quantity confirmation step to determine the number N of cavities opened on the volute wall surface. At this time, the angular interval between each cavity is , with the unit: rad.

[0011] In a preferred example of the present application, it can be further configured as follows: it further includes a separation step to determine the number of layers n of the partitions in the cavity, and they are evenly arranged in the cavity body.

[0012] The present application has the following advantages:

[0013] By opening a cavity structure on the wall surface of the pump's pressure water chamber and utilizing the compressibility of the air stored in the cavity, the pressure pulsation caused by the dynamic and static interference is buffered, thereby achieving the purpose of reducing vibration and noise of the water pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the cavity and partition structure of the present application.

[0015] Figure 2 is a schematic diagram of the cavity and partition structure of another embodiment of the present application.

[0016] Reference signs: 1, cavity; 2, partition. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following further describes the present application in detail with reference to the drawings.

[0018] Referring to Figure 1 and Figure 2 , a pump pressure water chamber disclosed in the present application includes a volute. Cavities 1 are provided on the inner wall surface of the volute. There are N cavities 1, and the angular interval between adjacent cavities 1 is . There are n layers of partitions 2 in the cavity 1. n takes values from 2 to 5, and the material strength of the partition 2 is not less than that of the volute. The structure of the cavity 1 is a polyhedron, a sphere or a hemisphere.

[0019] The present application also discloses a design method for a pump pressure water chamber for designing the above-mentioned pump pressure water chamber: including the following steps, a step of obtaining the inner wall surface pressure of the volute, obtaining the pressure value p acting on each unit area of the centrifugal pump volute wall surface, , where H is the designed head of the centrifugal pump, with the unit of m; ρ is the liquid density, with the unit of kg / m 3 ; g is the acceleration due to gravity, with the unit of m / s 2。C is the pulsation coefficient, taking values from 1.5 to 5;

[0020] Calculation steps for the inlet area of cavity 1. The inlet area of cavity 1 satisfies the formula , where p is the pressure value per unit area acting on the volute wall of the centrifugal pump, with the unit of N / m 2 ; A is the inlet area of cavity 1, with the unit of m 2 ; is the liquid surface tension, with the unit of N / m; L is the perimeter length of the opening of cavity 1, with the unit of m;

[0021] Calculation steps for the volume of cavity 1. The volume of cavity 1 satisfies the formula , where V is the volume of the structure of cavity 1, with the unit of m 3 ; A is the inlet area of the structure of cavity 1, with the unit of m 2 ; b is the depth of cavity 1 in the direction of the volute wall thickness , k = 0.1 - 0.3, with the unit of m;

[0022] Quantity confirmation step. Determine the number N of cavities 1 opened on the volute wall. At this time, the interval angle between each cavity 1 is , unit: rad;

[0023] Separation step. Determine the number of layers n of the partition 2 in cavity 1, and it is evenly arranged in the cavity body. See Figure 1 . The partitions in the same layer can be arranged in the same vertical plane. At this time, the partitions in the same layer form a cross-channel. In a preferred embodiment, the width of the cross-channel in the width direction of the cavity accounts for 1 / 5 - 1 / 6 of the width of the cavity, and the width of the cross-channel in the length direction of the cavity accounts for 1 / 5 - 1 / 6 of the length of the cavity. See Figure 2 . The partitions 2 can also be arranged staggeredly.

[0024] In a specific embodiment, the designed head H of the centrifugal pump is 15m, the volute wall thickness t is 0.012m, the volute outlet diameter is 0.12m, the axial width of the volute is 0.028m, the liquid transported in the centrifugal pump is water at 20°C, and its surface tension is 0.0728N / m. The cavity structure is selected as a cuboid.

[0025] The detailed design steps are as follows:

[0026] S1: Derive and calculate the pressure per unit area acting on the volute wall of the centrifugal pump in combination with the Bernoulli equation

[0027] (1)

[0028] In the formula, take C = 1.5.

[0029] S2: Considering the relationship between the pressure of the liquid acting on the volute wall and the liquid surface tension, assume that the surface side lengths of the cuboid cavity on the volute wall are \(a\) and \(c\). Then, according to formula (2)

[0030] (2)

[0031] In the formula , , .

[0032] The relational expression is calculated as , where . Take .

[0033] S3: According to the calculation in step S2, the inlet area of the cavity structure .

[0034] Furthermore, the volume of the cavity structure can be calculated according to formula (3):

[0035] (3)

[0036] In the formula, take .

[0037] S4: According to steps S1 to S3, the size of the cavity structure is 0.5 mm×0.0006 mm×1.2 mm. 36 cavities are opened on the volute wall by laser etching technology, and the interval angle between each cavity is 10°. Five layers of partitions are arranged in each cavity body, the thickness of the partition is 0.05 mm, and the partitions are spaced 0.18 mm in the thickness direction of the volute wall and fixed by micro-welding technology.

[0038] The implementation principle of this embodiment is as follows: By opening a cavity structure on the wall of the pump pressure chamber and utilizing the compressibility of the air stored in the cavity, the pressure pulsation caused by the dynamic-static interference is buffered, thereby achieving the purpose of reducing the vibration and noise of the water pump.

[0039] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A design method for a pump water chamber, used for designing a pump water chamber, characterized in that: It includes a volute. At least one circle of cavities is provided on the inner wall surface of the volute. There are N cavities in one circle, and the interval angle between adjacent cavities is It further includes the following steps: the step of obtaining the pressure on the inner wall surface of the volute, obtaining the pressure value p per unit area acting on the wall surface of the centrifugal pump volute; the step of calculating the cavity inlet area, and the cavity inlet area satisfies the formula In the formula, p is the pressure value per unit area acting on the wall surface of the centrifugal pump volute, and the unit is N / m 2 ; A is the cavity inlet area, and the unit is m 2 ; σ is the liquid surface tension, and the unit is N / m; L is the perimeter length of the cavity opening, and the unit is m. The step of calculating the cavity volume, and the cavity volume satisfies the formula V = Ab. In the formula, V is the volume of the cavity structure, and the unit is m 3 ; A is the inlet area of the cavity structure, and the unit is m 2 ; b is the depth of the cavity structure in the direction of the volute wall thickness, and the unit is m.

2. The design method of a pump water chamber according to claim 1, characterized in that: p = C·ρgH, where H is the designed head of the centrifugal pump in m; ρ is the liquid density in kg / m 3 ; g is the acceleration due to gravity in m / s 2 ; C is the pulsation coefficient, taking values from 1.5 to 5.

3. The design method of a pump water chamber according to claim 1, characterized in that: It also includes a quantity confirmation step to determine the number N of cavities opened on the volute wall surface. At this time, the interval angle of each cavity is Unit: rad.

4. The design method of a pump water chamber according to claim 1 or 3, characterized in that: It further includes a separating step of determining the number of layers n of the spacer in the cavity, and the spacers are evenly arranged in the cavity body.

5. A design method of a pump water chamber according to claim 4, characterized in that: The material strength of the spacer in the cavity is not less than that of the volute.

6. A design method of a pump water chamber according to claim 1, characterized in that: The structure of the cavity is a polyhedron, a sphere or a hemisphere.

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