CN110985442A - Elliptical diaphragm structure for reducing pressure pulsation of centrifugal pump and design method thereof - Google Patents
Elliptical diaphragm structure for reducing pressure pulsation of centrifugal pump and design method thereof Download PDFInfo
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- CN110985442A CN110985442A CN201911279886.7A CN201911279886A CN110985442A CN 110985442 A CN110985442 A CN 110985442A CN 201911279886 A CN201911279886 A CN 201911279886A CN 110985442 A CN110985442 A CN 110985442A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
- F04D29/428—Discharge tongues
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/669—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for liquid pumps
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- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The invention discloses an elliptical diaphragm structure for reducing pressure pulsation of a centrifugal pump and a design method thereof. The centrifugal pump comprises a volute and an impeller, the impeller is eccentrically arranged in an accommodating cavity in the volute, an upper outlet is formed in one side of the volute, a partition tongue is formed in one side, close to the upper outlet, of the upper portion of the accommodating cavity, and inner contour lines of the partition tongue are sequentially arranged into a sine curve and an elliptic line in the direction from a cavity to the bottom of the upper outlet. The invention can effectively reduce the pressure pulsation in the centrifugal pump, and particularly has obvious optimization effect on the most serious pressure pulsation of the partition tongue, so that the dynamic and static interference influence of the impeller and the partition tongue is reduced to a lower level, and the noise and the vibration during the operation of the centrifugal pump are effectively reduced.
Description
Technical Field
The invention relates to an internal structure of a centrifugal pump in the field of fluid machinery and a design method thereof, in particular to a design method of an elliptical diaphragm for reducing pressure pulsation of the centrifugal pump.
Background
The centrifugal pump is used as an important fluid conveying machine and is more and more widely applied to the fields of chemical industry, petroleum, electric power, metallurgy, coal, aerospace, aviation and the like. According to statistics, the power consumption of the pump accounts for about 15% of the total power generation amount of the whole country. The stability of the centrifugal pump operation is of great significance to the whole working system. However, in the working process of the centrifugal pump, the fluid flows in the centrifugal pump in a complex manner, and the pulsation induced vibration and noise of the fluid seriously affect the equipment and the surrounding environment, so that the stable operation of the centrifugal pump is seriously affected.
The noise and vibration inside the centrifugal pump are mainly caused by the dynamic and static interference of the volute and the impeller, and particularly the volute partition tongue is a very important factor influencing the pressure pulsation and radial force of the flow field inside the centrifugal pump. The traditional design only considers changing the outer diameter of the impeller or the base circle diameter of the volute to improve the flow condition of the internal fluid, but the effect is not ideal.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a design method of an elliptical baffle tongue for reducing pressure pulsation of a centrifugal pump, which reduces the pressure pulsation in the centrifugal pump to achieve the effects of vibration reduction and noise reduction.
The present invention achieves the above-described object by the following technical means.
An oval-shaped baffle structure for reducing pressure pulsation of a centrifugal pump comprises:
the centrifugal pump comprises a volute and an impeller, the impeller is eccentrically arranged in an accommodating cavity in the volute, an inner contour line of the accommodating cavity of the volute is a spiral line, an upper outlet is formed in one side of the volute, a partition tongue is formed in one side, close to the upper outlet, of the upper part of the accommodating cavity, and a sine curve and an elliptic line are sequentially arranged along the direction from the cavity to the bottom of the upper outlet on the inner contour line of the partition tongue.
One end of the sine curve is in tangent connection with the inner contour line of the volute cavity, the other end of the sine curve is in tangent connection with one end of the elliptic line, and the other end of the elliptic line is connected to the bottom edge of the upper outlet.
The main body of the inner contour line of the partition tongue is an elliptical line, and the elliptical line and the inner contour line of the volute cavity are in sinusoidal transition.
Secondly, a design method of an oval-shaped baffle structure for reducing pressure pulsation of a centrifugal pump comprises the following steps:
1) a straight line is made at the position of a circle center O of the impeller to serve as a radial line, the radial line and a horizontal line on the upper outlet side form an acute angle theta, the acute angle theta is arranged according to the following formula, and the radial line and a spiral line of an inner contour line of the volute cavity intersect at a point B:
in the formula, t is the maximum curvature of a spiral line of the inner contour line of the volute cavity; r represents the impeller base circle radius, mm;
2) and a straight line perpendicular to the line segment OB is taken as a tangential line after passing the point B, a vertical line is taken as a starting point A of a spiral line of the inner contour line of the volute chamber, a straight line which is close to the point B and forms an included angle of α with the vertical line is taken as a reference line after passing the starting point A of the spiral line of the inner contour line of the volute chamber, the starting point A of the spiral line of the inner contour line of the volute chamber is positioned on a horizontal line at the upper outlet side, the intersection point C of the tangential line and the reference line is taken as the position of the starting point of the volute partition tongue, and an acute angle formed by the line segment OC and the line segment OA is.
3) Taking a connecting line BC between the point B and the point C as the major axis of the ellipse, taking the shortest distance between the point B and the impeller contour as the length of the minor semi-axis of the ellipse, and making an elliptic curve, wherein the elliptic curve is intersected with a circle taking the circle center O of the impeller and the radius as a connecting line OB at a point D;
4) drawing a vertical line through D to intersect with the connecting line BC at a point E, drawing an elliptic curve by taking the point E as the center of an ellipse, taking the connecting line DE as a short semi-axis and taking the connecting line EC as a long semi-axis, and taking a curve segment CD on the elliptic curve as a main body shape line of the isolating tongue;
5) setting a sine curve between the point B and the point D, determining the sine curve by taking the point B as an origin, taking the direction of the connecting line BD as an x axis and taking the direction vertical to the connecting line BD as a y axis according to the following formula, and taking the 1 st and 2 nd period parts of the sine curve as the rest shape lines of the tongue;
in the formula, n is the rotating speed of the centrifugal pump, r/min;
q-rated flow, m, of the centrifugal pump3/s；
H-rated lift of the centrifugal pump, m;
l is the distance of the connecting line between the point B and the point D, and is mm;
a-sinusoidal amplitude, mm.
The included angle α takes the value as follows, the specific rotating speed of the centrifugal pump is 2 degrees when being 10-80 degrees, the specific rotating speed is 3 degrees when being more than 80-150 degrees, and the specific rotating speed is 5 degrees when being more than 150-300 degrees.
The invention has the beneficial effects that:
the invention has the advantages that according to the centrifugal pumps with different working requirements, the tongue-shaped line is designed by utilizing the parameters obtained by the fluid centrifugal motion rule, and the elliptical line at the head of the tongue can effectively reduce the pressure pulsation at the tongue so as to reduce the vibration and the noise; the sine line between the elliptic curve and the spiral line can effectively reduce the turbulence degree of the fluid and improve the overall efficiency of the centrifugal pump.
The invention can effectively reduce the pressure pulsation in the centrifugal pump, particularly has obvious optimization effect on the most serious pressure pulsation of the partition tongue, reduces the dynamic and static interference influence of the impeller and the partition tongue to a lower level, effectively reduces the noise and vibration during the operation of the centrifugal pump, and has better optimization effect on the centrifugal pump with high specific speed.
Drawings
FIG. 1 is a schematic view of the overall design of a tongue-shaped line;
FIG. 2 is a schematic diagram illustrating the establishment of the sine curve starting point angle;
FIG. 3 is a schematic diagram illustrating the establishment of the end point of the tongue-isolating elliptic curve;
FIG. 4 is a schematic view of an elliptic curve of the tongue;
FIG. 5 is a schematic view of a sinusoid;
FIG. 6 is a graph comparing pressure fluctuations of the centrifugal pump of the present invention with a standard centrifugal pump;
FIG. 7 is a graph of the pressure pulsation frequency spectrum of the centrifugal pump of the present invention and a standard centrifugal pump.
In the figure: the spiral casing (1), the impeller (2), the partition tongue (3), the sine curve (4) and the elliptic line (5).
Detailed Description
The invention is further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.
As shown in fig. 1, the centrifugal pump includes a volute 1 and an impeller 2, the impeller 2 is eccentrically arranged in a cavity inside the volute 1, an inner contour of the cavity of the volute 1 is a spiral line, an upper outlet is arranged at one side of the volute 1, a tongue 3 is formed at one side of the upper part of the cavity close to the upper outlet, and the inner contour of the tongue 3 is connected between the cavity and the bottom of the upper outlet.
The embodiment of the invention and the implementation thereof are as follows:
1) as shown in fig. 2, the centrifugal pump in the closed structure is designed in this example, and the parameters are as follows: rated flow 46.3m3H, rated lift 480.6m, impeller rotating speed 14400r/min, impeller outer diameter 116mm and volute base circle radius 62 mm. The width of the volute outlet is 80 mm. The center of the impeller is O, and the starting point of the spiral line is A.
A straight line is made at the center O of the impeller 2 to serve as a radial line, the radial line and a horizontal line at the upper outlet side form an acute angle theta, the acute angle theta is set according to the following formula, and the radial line and a spiral line of an inner contour line of the cavity of the volute 1 intersect at a point B:
2) in the concrete implementation, the included angle α is 5 degrees.3) as shown in figure 3, a connecting line BC between the point B and the point C is used as the long axis of an ellipse, the shortest distance between the point B and the outline of the impeller 2 is used as the length of the short half axis of the ellipse, and the ellipse curve intersects a circle which takes the circle center O of the impeller 1 and the radius as the connecting line OB at a point D;
4) as shown in fig. 4, a perpendicular line crossing the connecting line BC is made through D to intersect the connecting line BC at the point E, DE ⊥ BC, an elliptic curve is made with the point E as the center of the ellipse, the connecting line DE as the minor semi-axis and the connecting line EC as the major semi-axis, and the curve segment CD on the elliptic curve is used as the main body shape line of the partition tongue 3;
5) setting a sine curve between a point B and a point D, taking B as an origin, taking the direction of a connecting line BD as an x axis, taking the direction vertical to the connecting line BD as a y axis, determining the sine curve according to the following formula, and taking the 1 st and 2 nd period parts of the sine curve as the rest lines of the separation tongue 3, as shown in FIG. 5;
the centrifugal pump designed by the method and a standard centrifugal pump are subjected to a simulation numerical simulation test, and 12 monitoring points are annularly arranged in volute runners of the standard centrifugal pump and the centrifugal pump and are subjected to unsteady numerical simulation calculation.
Through analysis of test results, as shown in fig. 6, steady numerical simulation calculation is performed on the standard centrifugal pump and the centrifugal pump of the design under four working condition points of 0.6Q, 0.8Q, 1.0Q and 1.2Q of flow measurement. H1And η1For the lift and efficiency of a standard centrifugal pump, H2And η2The centrifugal pump is designed with the lift and the efficiency. The lift of the standard centrifugal pump at 0.6Q is 514.92m, and the efficiency is 43.82%; efficiency of 0.8Q lift 515.329m50.45 percent; the efficiency was 55.77% at 512.538m lift at 1.0Q and 57.23% at 506.193m lift at 1.2Q. The centrifugal pump has the advantages that the efficiency is 43.17% when the pump lift is 533.35m at 0.6Q; the lift at 0.8Q is 534m, and the efficiency is 53.12 percent; the efficiency is 58.04% when the lift is 531m at 1.0Q; the efficiency is 60.81% when the lift at 1.2Q is 510 m. It can be seen that the centrifugal pump of this design has a higher overall head than a standard centrifugal pump. The efficiency of the centrifugal pump is slightly lower than that of a standard centrifugal pump under the condition of small flow, but the efficiency of the centrifugal pump is higher than that of the standard centrifugal pump under most working conditions along with the increase of the flow.
Through analysis of test results, as shown in fig. 7, the numerical value is the difference between the pressure value of each monitoring point and the average pressure of the monitoring point in one period, and it can be seen that the overall pressure fluctuation of the centrifugal pump of the design is smaller than that of a standard centrifugal pump. As shown in fig. 7, pressure data for each step in the unsteady numerical simulation calculation is extracted for each monitoring point, and fast fourier transform is performed. It can be seen that the centrifugal pump of the design has greatly improved low-frequency and high-frequency pulsation compared with the standard centrifugal pump. The amplitude of each monitoring point is reduced. And the amplitude change at the frequency of about 6000 is very obvious, and the consistency is better. The centrifugal pump has obvious improvement on different points of the same frequency band, particularly, the influence of dynamic and static interference is strongest, and the improvement effect on the tongue isolating position with the largest pulsation amplitude is most obvious.
Therefore, compared with the traditional centrifugal pump, the design method provided by the invention has the advantages of better performance of reducing pressure pulsation, improving efficiency and reducing vibration and noise. The optimization effect is better especially for a high-speed centrifugal pump.
The examples are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.
Claims (5)
1. The utility model provides a reduce oval type spacer tongue structure of centrifugal pump pressure pulsation, the centrifugal pump include spiral case (1) and impeller (2), impeller (2) eccentric arrangement is in spiral case (1) inside appearance intracavity, spiral case (1) one side is equipped with the export, holds one side that chamber upper portion is close to the export and forms spacer tongue (3), its characterized in that: the inner contour line of the partition tongue (3) is sequentially arranged into a sine curve (4) and an elliptic line (5) along the direction from the cavity to the bottom of the upper outlet.
2. The elliptical diaphragm structure for reducing pressure pulsation in a centrifugal pump according to claim 1, wherein: one end of the sine curve (4) is in tangent connection with an inner contour line of a cavity of the volute (1), the other end of the sine curve (4) is in tangent connection with one end of the elliptic line (5), and the other end of the elliptic line (5) is connected to the bottom edge of the upper outlet.
3. A design method of an elliptical baffle structure for reducing pressure pulsation of a centrifugal pump is characterized in that:
1) a straight line is made at the position of a circle center O of the impeller (2) and serves as a radial line, the radial line and a horizontal line on the upper outlet side form an acute angle theta, the acute angle theta is arranged according to the following formula, and the radial line and a spiral line of an inner contour line of the cavity of the volute (1) intersect at a point B:
in the formula, t is the maximum curvature of a spiral line of an inner contour line of the cavity of the volute (1); r represents the base circle radius of the impeller (2), mm;
2) and a straight line perpendicular to the line segment OB is taken as a tangential line through the point B, a vertical line is taken as a starting point A of a spiral line of the inner contour line of the cavity of the volute (1), a straight line which is close to the point B and forms an included angle of α with the vertical line is taken as a reference line through the starting point A of the spiral line of the inner contour line of the cavity of the volute (1), and an intersection point C of the tangential line and the reference line is taken as the position of the starting point of the volute partition tongue.
3) Taking a connecting line BC between the point B and the point C as the major axis of the ellipse, taking the shortest distance between the point B and the outline of the impeller (2) as the length of the minor semi-axis of the ellipse, and making an elliptic curve, wherein the elliptic curve is intersected with a circle taking the circle center O and the radius of the impeller (1) as a connecting line OB at a point D;
4) drawing a vertical line through D to intersect with the connecting line BC at a point E, drawing an elliptic curve by taking the point E as the center of an ellipse, taking the connecting line DE as a minor semi-axis and taking the connecting line EC as a major semi-axis, and taking a curve segment CD on the elliptic curve as a main body shape line of the separation tongue (3);
5) setting a sine curve between the point B and the point D, determining the sine curve by taking the point B as an origin and taking the direction of a connecting line BD as an x axis according to the following formula, and taking the 1 st and 2 nd period parts of the sine curve as the rest shape lines of the separation tongue (3);
in the formula, n is the rotating speed of the centrifugal pump (1), r/min;
q-rated flow, m, of the centrifugal pump (1)3/s；
H-rated lift of the centrifugal pump (1), m;
l is the distance of the connecting line between the point B and the point D, and is mm;
a-sinusoidal amplitude, mm.
4. The design method of the elliptical diaphragm structure for reducing the pressure pulsation of the centrifugal pump according to claim 3, wherein the included angle α is defined as 2 degrees when the specific rotating speed of the centrifugal pump is 10-80 degrees, 3 degrees when the specific rotating speed is greater than 80-150 degrees and 5 degrees when the specific rotating speed is greater than 150-300 degrees.
5. The utility model provides a reduce oval type spacer tongue structure of centrifugal pump pressure pulsation which characterized in that: manufactured by the design method of claim 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911279886.7A CN110985442A (en) | 2019-12-13 | 2019-12-13 | Elliptical diaphragm structure for reducing pressure pulsation of centrifugal pump and design method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911279886.7A CN110985442A (en) | 2019-12-13 | 2019-12-13 | Elliptical diaphragm structure for reducing pressure pulsation of centrifugal pump and design method thereof |
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| CN110985442A true CN110985442A (en) | 2020-04-10 |
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| CN201911279886.7A Pending CN110985442A (en) | 2019-12-13 | 2019-12-13 | Elliptical diaphragm structure for reducing pressure pulsation of centrifugal pump and design method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114427545A (en) * | 2021-12-28 | 2022-05-03 | 威乐(中国)水泵***有限公司 | Bionic water pump shell, isolation tongue of shell and design method of isolation tongue |
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2019
- 2019-12-13 CN CN201911279886.7A patent/CN110985442A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114427545A (en) * | 2021-12-28 | 2022-05-03 | 威乐(中国)水泵***有限公司 | Bionic water pump shell, isolation tongue of shell and design method of isolation tongue |
| CN114427545B (en) * | 2021-12-28 | 2024-02-06 | 威乐(中国)水泵***有限公司 | Bionic water pump shell, partition tongue of shell and design method of partition tongue |
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