Design method for double volutes of centrifugal pump

Abstract

The invention discloses a centrifugal pump double-volute design method which comprehensively considers the smoothness of a pump shell fixing surface, the minimum resistance of a runner section close to a circle, the minimum influence on an inlet runner and the uniformity of design and 3D modeling. The design of rectangular sections and fillets is adopted for the pump shell from 0 degree to the end of an inner baffle tongue to approach a circle so as to reduce resistance, the widths of the sections of internal flow channels of a first outer volute and a first inner volute connected with a base circle are fixed and are arrayed in a 180-degree mode, and therefore the fixed face of the pump shell can be flat and the influence on a pump inlet flow channel is minimum due to the fact that the widths are fixed. And the design of the inner flow channel and the outer flow channel and 3D modeling are unified, so that the working efficiency of the centrifugal pump is integrally improved, and the weight of the pump shell is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of double volute design and 3D modeling of centrifugal pumps, and in particular to a double volute design and 3D modeling method for a high-efficiency flow passage with a rectangular chamfered cross section. Background Art

[0002] As a vital piece of equipment for fluid transportation, the performance of a centrifugal pump directly impacts the overall system efficiency. In recent years, the double-volute design has garnered significant attention in the centrifugal pump sector. The double-volute design is an improvement on the traditional single-volute design. By dividing the volute into two sections, it achieves a more uniform flow of fluid within the pump, reduces vortex and backflow, and balances radial forces within the volute. This improves hydraulic efficiency, reduces vibration and noise, and extends the pump's lifespan. With the continuous advancement of industrial technology, centrifugal pumps are increasingly being used in various fields. As an advanced pump structural design concept, the double-volute design will be more widely used and promoted in the future. Centrifugal pumps with double-volute designs will play a particularly important role in fields with high performance requirements, such as petrochemicals, electric power, and water treatment.

[0003] Currently, most double volute designs on the market still follow the 2D design method from textbooks over 100 years ago. They are based on a boundary with multiple intersecting arcs or straight lines. The cross-section is a mixture of a small circle with a gradually changing angle to a large circle or a trapezoidal angle to a large circle. This is an unsmooth and backward single volute design and modeling method. Separation tongues are added to the single volute to achieve the double volute design. This method does not take into account the overall surface smoothness, flow efficiency, 3D modeling and the entire life cycle of the pump.

[0004] For example: 1. The cross-sections of the inner and outer flow channels after being divided into small circles or trapezoidal sections are greatly different from the circular cross-sections. That is, the perimeter of the same cross-sectional area is too large, the flow channel resistance is greater, and the efficiency is lower;

[0005] 2. The outer width of the flow channel near the base circle becomes larger and larger starting from the 0-degree angle of the diaphragm. After a full circle of 360 degrees, the width is much larger than the beginning. The mounting flange near the base circle needs to be made very thick, resulting in serious material waste. In addition, when designing a double-suction pump or pipeline pump, the inlet flow channel will have to bypass the large end of the gradually changing semicircular or trapezoidal volute, wasting material. If it cannot be avoided, it must pass through the large end of the double volute with wide resistance, which increases the inlet flow channel resistance and further reduces the efficiency of the pump.

[0006] 3. The number of cross-sectional lines segmented by angle is often different, which is not conducive to the unified parametric design requirements of the volute. Summary of the Invention

[0007] In response to the problems in the related art, the present application discloses a design method for a double volute of a centrifugal pump, which solves the problems existing in the background art.

[0008] To achieve the above objectives, this application provides the following technical solutions:

[0009] A design method for a double volute of a centrifugal pump includes an outer volute and an inner volute, wherein the outer volute and the inner volute are separated by an inner partition tongue, and a base circle is provided at the center of the double volute of the centrifugal pump.

[0010] The first outer volute is provided on the outside of the base circle from 0 to 180 degrees.

[0011] The base circle is provided with a first inner volute outside from 180 degrees to 360 degrees, a second outer volute is provided outside the first inner volute, and an inner partition tongue is provided between the first inner volute and the second outer volute.

[0012] The first inner volute is connected to the second inner volute from 360 degrees to the end of the inner partition tongue, and the second outer volute is connected to the third outer volute from 360 degrees to the end of the inner partition tongue.

[0013] The second inner volute and the third outer volute are connected at the outlet end to form an outlet volute, and an outlet flow channel is provided inside the outlet volute.

[0014] The first outer volute, the second outer volute and the third outer volute are connected, assembled and rounded to form an outer volute.

[0015] The first inner volute and the second inner volute are connected, combined and rounded to form an inner volute.

[0016] An outer flow channel is provided inside the outer volute, and an inner flow channel is provided inside the inner volute.

[0017] As a further solution of the present application: the cross-sections of the outer flow channel and the inner flow channel are rectangular.

[0018] As a further solution of the present application: the internal flow channel of the first outer volute from 0 degrees to 180 degrees is a rectangular equal-width cross-section.

[0019] As a further solution of the present application: the width of the rectangular cross-section of the internal flow channel of the second outer volute and the third outer volute gradually and smoothly increases from 180 degrees to the end of the inner partition tongue, and the height of the rectangular cross-section of the internal flow channel of the second outer volute and the third outer volute gradually and smoothly increases.

[0020] As a further solution of the present application: the internal flow channel of the first inner volute from 180 degrees to 360 degrees is a rectangular equal-width cross-section, which is the same as the internal flow channel of the first outer volute and is distributed in a 180-degree array.

[0021] As a further solution of the present application: the width of the rectangular cross-section of the internal flow channel of the second inner volute increases gradually and smoothly from 360 degrees to the end of the inner partition tongue, and the height of the rectangular cross-section of the internal flow channel of the second inner volute increases gradually and smoothly.

[0022] As a further solution of the present application: the cross-sectional widths of the outer flow channel and the inner flow channel are equal at the end of the inner partition tongue.

[0023] As a further solution of the present application: the 3D modeling of the outer volute and the inner volute uses the arc of the base circle as a scanning curve and controls the outer contour with a control line.

[0024] In summary, the beneficial effects of this application are:

[0025] This design method comprehensively considers the flatness of the pump casing fixing surface, the minimum resistance of the flow channel cross-section close to a circle, the minimum impact on the inlet flow channel, and the unity of design and 3D modeling. The pump casing adopts a rectangular cross-section with chamfered corners from 0 degrees to the end of the inner diaphragm to approach a circle and reduce resistance.

[0026] The cross-sectional width of the flow passages inside the first outer volute and the first inner volute connecting the base circle is fixed and arranged in a 180-degree array. This fixed width ensures a smooth mounting surface for the pump casing and minimizes the impact on the pump inlet flow passage. Furthermore, the design and 3D modeling of the inner and outer flow passages are unified, improving the overall efficiency of the centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application.

[0028] In the attached figure:

[0029] Figure 1 This is the design view of the first step of the double volute flow passage.

[0030] Figure 2 This is the design view of the second step of the double volute flow passage.

[0031] Figure 3 This is the design view of the double volute flow passage in step 3.

[0032] Figure 4 This is the design view of the double volute flow passage in step 4.

[0033] Figure 5 This is the design view of the double volute flow passage in step 5.

[0034] Figure 6 This is the design view of the double volute flow passage in step 6.

[0035] Figure 7 This is the design view of the double volute flow passage in step 7.

[0036] Figure 8 It is the changing curve of the width and angle of the inner and outer flow channels of the double volute.

[0037] Figure 9 This is the side view of the design of the double volute flow passage in step 5.

[0038] Figure 10 This is the side view of the design of the double volute flow passage in step 6.

[0039] Notes on reference numerals:

[0040] O, base circle center; JY, base circle; J, base circle radius; Ang, change angle; HA, (corresponding to the change angle) volute section height; DK: minimum width of rectangular section; MK: middle width of rectangular section; EK: maximum width of rectangular section; TK: thickness of inner tongue;

[0041] A0, 0 degree starting angle; A180, 180 degree angle; A360, 360 degree angle; AGE, end angle of inner septum tongue; AM, angle from A360 to AGE; AOut, angle of outlet section; Q, center of focus of A360 and AGE section line; AW, arc line with Q as center between A360 and AGE sections; W, radius of AW arc;

[0042] W1, first outer volute; N1, first inner volute; W2, second outer volute; W3, third outer volute; N2, second inner volute; OV, outlet volute;

[0043] LS, outer curve of volute W1; LW, outer curve of the entire volute from A0 to AOut; LN, inner curve of the volute from A360 to AOut; LSZ, outer curve of volute N1; LGW, inner curve of volute W3; LGN, outer curve of volute N2; LSD, inner curve of volute W2; LRN, guide curve for inner chamfer of volute from A360 to AGE; LRW, guide curve for outer chamfer of volute from A0 to AGE; LRG, guide curve for chamfer at the tongue of double volute;

[0044] SGE, outer cross-section line of volute at AGE; SOut, cross-section line of volute outlet;

[0045] SRW, outer flow channel width change curve; SRN, inner flow channel width change curve. DETAILED DESCRIPTION

[0046] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0047] It should be noted that all directional indications in the embodiments (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "first" and "second" in the embodiments are only for descriptive purposes and do not specifically refer to the order or ranking, nor are they used to limit the present application. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0049] In order to further understand the content, features and effects of the present application, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0050] like Figure 1-10 As shown:

[0051] A double volute design method for a centrifugal pump comprises an outer volute and an inner volute, wherein the outer volute and the inner volute are separated by an inner partition tongue, and a base circle is provided at the center of the double volute of the centrifugal pump.

[0052] Among them, a first outer volute W1 is provided on the outside of the base circle JY from 0 degrees to 180 degrees, a first inner volute N1 is provided on the outside of the base circle JY from 180 degrees to 360 degrees, a second outer volute W2 is provided on the outside of the first inner volute N1, an inner partition tongue is provided between the first inner volute N1 and the second outer volute W2, the first inner volute N1 is connected to the second inner volute N2 from 360 degrees to the end of the inner partition tongue, the second outer volute W2 is provided with a third outer volute W3 from 360 degrees to the end of the inner partition tongue, the second inner volute N2 and the third outer volute W3 are connected at the outlet end to form an outlet volute OV, and an outlet flow channel is provided inside the outlet volute OV.

[0053] The first outer volute W1, the second outer volute W2, and the third outer volute W3 are connected, assembled, and chamfered to form an outer volute. The first inner volute N1 and the second inner volute N2 are connected, assembled, and chamfered to form an inner volute. An outer flow channel is provided inside the outer volute, and an inner flow channel is provided inside the inner volute. The cross-sections of the outer and inner flow channels are rectangular.

[0054] The internal flow channel of the first outer volute W1 from 0 degrees to 180 degrees is a rectangular equal-width cross-section, and the width of the rectangular cross-section of the internal flow channels of the second outer volute W2 and the third outer volute W3 gradually and smoothly increases from 180 degrees to the end of the inner partition tongue, and the height of the rectangular cross-section of the internal flow channels of the second outer volute W2 and the third outer volute W3 gradually and smoothly increases.

[0055] The internal flow passage of the first inner volute N1, from 180 degrees to 360 degrees, is a rectangular cross-section of equal width, identical to the internal flow passage of the first outer volute W1 and distributed in a 180-degree array. From 360 degrees to the end of the inner septum, the width of the internal flow passage of the second inner volute N2 gradually and smoothly increases, and the height of the internal flow passage of the second inner volute N2 gradually and smoothly increases.

[0056] The cross-sectional width of the outer and inner flow channels is equal at the end of the inner diaphragm. The 3D modeling of the outer and inner volutes uses the arc of the base circle as the scanning curve and the control line to control the outer contour.

[0057] like Figure 1 As shown:

[0058] The outer edge curve LS of the first outer volute W1 is a section of the entire volute outer edge curve A0 to A180. W1 is a scanning curve based on the base circle JY with a radius of J between A0 and A180. The control curve is LS. The cross-section is a rectangle. The inner edge of the rectangle coincides with the base circle JY, and the outer edge of the rectangle coincides with the control curve LS. The width is the surface obtained by scanning with DK.

[0059] The width DK of the rectangular cross-section of the internal flow passage of the first outer volute W1 is a constant value, and the height of the rectangular cross-section of the internal flow passage of the first outer volute W1 increases gradually and smoothly.

[0060] like Figure 2 As shown:

[0061] The first inner volute N1 is obtained by arranging the first outer volute W1 at 180 degrees along the center of the base circle, that is, the outer edge curve LSZ of the first inner volute N1 is also obtained by the outer edge curve LS array of the first outer volute W1.

[0062] In this way, the width of the volute close to the base circle JY within a week from A0 to A360 is a constant value DK, that is, the upper and lower width planes are flat, without width difference, and no additional material is needed to fill the height difference to make the volute installation positioning flange, thereby saving materials.

[0063] like Figure 3 As shown:

[0064] LSD is obtained by the thickness TK of the inner diaphragm of LSZ offset. The second outer volute W2 is a scanning curve with the base circle JY of the A180 to A360 segment as the control curve, and the LSD and LW of the A180 to A360 segment as the control curve. The cross-section is still rectangular, the inner side of the rectangle coincides with the LSD, and the outer side coincides with the control curve LW. The width gradually increases from DK of A180 to MK of A360, and the surface is obtained by scanning.

[0065] like Figure 4 As shown:

[0066] The second inner volute N2 is a surface obtained by scanning with WJ as the center at Q and radius W, and the control curves are LGN and LN. The cross section is still rectangular, the inner edge of the rectangle coincides with LN, and the outer edge of the rectangle coincides with the control curve LGN. The width gradually increases from DK of A360 to EK of AGE.

[0067] Similarly, LGW is obtained by LGN offset from the inner diaphragm thickness TK. The third outer volute W3 is a scanning curve of the arc WJ with its center at Q and radius W. The control curves are LGW and LW. The cross-section is still rectangular. The inner edge of the rectangle coincides with LGW, and the outer edge of the rectangle coincides with the control curve LW. The width is a surface obtained by scanning from MK of A360 to EK of AGE.

[0068] like Figure 5 、 9 As shown:

[0069] The first outer volute W1, the first inner volute N1, the second outer volute W2, the second inner volute N2 and the third outer volute W3 are combined to form a complete rectangular cross-section volute. The combined rectangular volute is rounded according to the rounding guide curves LRN and LRW, and the complete rectangular cross-section angular volute is turned into a rounded volute, and the rectangular rounded outer cross-section line SGE is obtained in AGE.

[0070] like Figure 6 、 10 As shown:

[0071] The outlet volute OV is formed by mixing the section lines SGE and SOut as the first direction and the LN and LW curves from AGE to Aout as the second direction boundaries.

[0072] like Figure 7 As shown:

[0073] Bundle Figure 5 The combined chamfered volute is combined with the outlet volute OV, and then chamfered according to the guide curve LRG of a circle at the inner partition tongue, so that a complete volute is obtained which is not only rounded on the outside but also rounded on the inside of the partition tongue.

[0074] like Figure 8 As shown:

[0075] The variation curve of the rectangular cross-section of the entire volute is summarized. For the outer volute controlled by LW, the width variation curve SRW is in the segment from A0 to A180, and the cross-section width is a constant value DK. From A180 to A360 and then to AGE, the cross-section width gradually increases from DK to MK and then to EK. The width variation curve SRN of the inner volute is in the segment from A180 to A360, and the cross-section width is a constant value DK. From A360 to AGE, the cross-section width gradually increases from DK to EK.

[0076] The smoothness of curves SRW and SRN determines the smoothness of both sides of the volute width. This 3D design usually uses a 2nd-order continuous design curve. Similarly, LW, LN, LSZ, and LGN also usually use at least 2nd-order continuous design curves to control the smoothness of both sides of the volute height. That is, the smoothness of the curve controls the smoothness of the surface.

[0077] Finally, it should be noted that the above disclosure is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. The scope of the present application is limited only by the appended claims.

Claims

1. A method for designing a double volute of a centrifugal pump, characterized by: It includes an outer volute and an inner volute, which are separated by an inner partition tongue. A base circle is provided in the center of the double volute of the centrifugal pump. The first outer volute is provided on the outside of the base circle from 0 to 180 degrees. The base circle is provided with a first inner volute outside from 180 degrees to 360 degrees, a second outer volute is provided outside the first inner volute, and an inner partition tongue is provided between the first inner volute and the second outer volute. The first inner volute is connected to the second inner volute from 360 degrees to the end of the inner partition tongue, and the second outer volute is connected to the third outer volute from 360 degrees to the end of the inner partition tongue. The second inner volute and the third outer volute are connected at the outlet end to form an outlet volute, and an outlet flow channel is provided inside the outlet volute. The first outer volute, the second outer volute and the third outer volute are connected, assembled and rounded to form an outer volute. The first inner volute and the second inner volute are connected, combined and rounded to form an inner volute. An outer flow channel is provided inside the outer volute, and an inner flow channel is provided inside the inner volute.

2. A method for designing a double volute of a centrifugal pump according to claim 1, characterized in that: The cross sections of the outer flow channel and the inner flow channel are rectangular.

3. A method for designing a double volute of a centrifugal pump according to claim 2, characterized in that: The internal flow passage of the first outer volute from 0 degrees to 180 degrees is a rectangular equal-width cross-section.

4. A method for designing a double volute of a centrifugal pump according to claim 3, characterized in that: The width of the rectangular cross-section of the inner flow passage of the second outer volute and the third outer volute increases gradually and smoothly from 180 degrees to the end of the inner partition tongue, and the height of the rectangular cross-section of the inner flow passage of the second outer volute and the third outer volute increases gradually and smoothly.

5. The method for designing a double volute of a centrifugal pump according to claim 3, characterized in that: The internal flow passage of the first inner volute from 180 degrees to 360 degrees is a rectangular equal-width cross-section, which is the same as the internal flow passage of the first outer volute and is distributed in a 180-degree array.

6. A method for designing a double volute of a centrifugal pump according to claim 5, characterized in that: The width of the rectangular cross-section of the inner flow passage of the second inner volute increases gradually and smoothly from 360 degrees to the end of the inner partition tongue, and the height of the rectangular cross-section of the inner flow passage of the second inner volute increases gradually and smoothly.

7. A method for designing a double volute of a centrifugal pump according to claim 2, characterized in that: The cross-sectional widths of the outer flow channel and the inner flow channel are equal at the end of the inner partition tongue.

8. The method for designing a double volute of a centrifugal pump according to claim 1, characterized in that: The outer volute and the inner volute are 3D modeled by using the arc of the base circle as a scanning curve and controlling the outer contour with a control line.

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