阅读说明：本技术 一种双向泵站进水流道喇叭口设计方法 (Method for designing bell mouth of water inlet flow channel of bidirectional pump station ) 是由 袁建平 陆荣 李彦军 付燕霞 于 2021-08-27 设计创作，主要内容包括：本发明公开一种双向泵站进水流道喇叭口设计方法,利用喇叭口进行分段,得到喇叭口各部分的参数,并利用这些参数建立抛物线的方程式,通过求解方程式即可得到抛物线的具体线型,也即可以得到本发明的设计结构。本发明弥补了目前双曲线和椭圆设计法型线过渡不光顺,且不易于参数化设计的缺点。(The invention discloses a method for designing a bell mouth of a water inlet channel of a bidirectional pump station, which comprises the steps of utilizing the bell mouth to carry out segmentation to obtain parameters of each part of the bell mouth, utilizing the parameters to establish an equation of a parabola, and solving the equation to obtain the specific line form of the parabola, namely obtaining the design structure of the invention. The invention overcomes the defects that the line transition is not smooth and the parameterization design is not easy in the prior hyperbolic and elliptic design method.)

1. A method for designing a bell mouth of a water inlet channel of a bidirectional pump station is characterized by comprising the following steps:

modeling: the water inlet channel comprises a bell mouth (1), a water guide cone (2) and a partition pier (3); the top surface of the partition pier (3) is provided with the water guide cone (2); the bell mouth (1) is sleeved outside the water guide cone (2);

segmenting: dividing the section line of the bell mouth (1) into three sections: a first straight line (5), a parabola (6) and a second straight line (7);

establishing a coordinate system: establishing a rectangular coordinate system at the center of the top surface of the bell mouth (1), writing out an equation of the parabola (6), and listing an equation set which the parabola (6) should meet according to a known geometric condition;

establishing a formula: and solving an equation set to obtain the parabola (6) equation, and finally drawing the molded line of the bell mouth (1).

2. The method for designing the bell mouth of the water inlet channel of the bidirectional pump station according to claim 1, wherein the method comprises the following steps: in the modeling step, the bell mouth (1) and the water guide cone (2) are coaxially arranged; the small opening at the top end of the water guide cone (2) is flush with the small opening at the top end of the bell mouth (1); the bottom opening of the water guide cone (2) is flush with the bottom surface of the partition pier (3).

3. The method for designing the bell mouth of the water inlet channel of the bidirectional pump station according to claim 2, is characterized in that: in the segmentation step, the parabola (6) is connected between the first straight line (5) and the second straight line (7), and the parabola (6) is tangent to the first straight line (5) and the second straight line (7) respectively; the tangent points are respectively Q₁And Q₂。

4. The method for designing the bell mouth of the water inlet channel of the bidirectional pump station according to the claim 3, is characterized in that: in the step of establishing a coordinate system, the center point of an outlet at the top of the bell mouth (1) is taken as a circle center O, the horizontal direction is an X axis, and the vertical direction is a Y axis; the parabola (6) is a quadratic parabola whose equation is:

Y＝aX²+bX+c

wherein a, b and c are coefficients to be solved;

and (3) listing an equation set according to the established coordinate system and the geometric relation:

wherein: x is the number of₀,y₀Is a tangent point Q₁Or Q₂The coordinates of (a); alpha is an included angle between the second straight line (7) and the positive direction of the Y axis; d₀The diameter of the top surface of the bell mouth (1); d₁Is the diameter of the lowest point of the bell mouth (1); h is₀And tangent point Q₁Or Q₂Are equal in ordinate, h₁Is from the lowest point of the bell mouth (1) to a tangent point Q₁Or Q₂Height in the Y direction of (a).

5. The method for designing the bell mouth of the water inlet channel of the bidirectional pump station according to claim 4, wherein the method comprises the following steps: solving the system of equations to obtain the coefficients of the equation of the parabola (6) as follows:

wherein: h is₂Is the Y-direction height from the lowest point of the bell mouth to the bottom surface of the partition pier (3),

h is the height H from the top surface of the bell mouth (1) to the bottom surface of the partition pier (3): namely:

h₀+h₁+h₂＝H

drawing the shape of the parabola (6) according to the equation of the parabola (6), and drawing the second straight line (7), the parabola (6) and the first straight line (5) according to the geometric relationship, thereby designing the section profile of the bell mouth (1).

Technical Field

The invention relates to the technical field of hydraulic engineering, in particular to a method for designing a bell mouth of a water inlet flow channel of a bidirectional pump station.

Background

The pump station is an important large-scale water transfer project and plays an important role in solving the problems of insufficient regional water supply, agricultural irrigation and drainage, urban flood control and drainage and the like. As a special low water head pump station system with a bidirectional drainage function, the vertical bidirectional pump station is widely applied to irrigation and drainage in China. However, two outstanding problems exist in the bidirectional pump station which is constructed and completed in China at present: one is the low running efficiency of the pump station, and the other is the strong vibration of the unit in the running process. The two main reasons are that the design of the water inlet flow channel has defects, so that the inflow of the water pump is unstable. The bell mouth is used as an important structure in the bidirectional water inlet flow passage and plays an important role in inflow stability of the water pump. At present, the design of the section profile of the horn mouth of the bidirectional flow channel mainly depends on the experience of designers, and although hyperbola and ellipse are applied to the design of the section profile of the horn mouth, the parameterization design is difficult, and the profile transition is not smooth enough.

Disclosure of Invention

The invention aims to provide a method for designing a bell mouth of a water inlet flow channel of a bidirectional pump station, which aims to solve the problems in the prior art and overcome the defects that the line transition is not smooth and the parametric design is not easy to realize by the conventional hyperbolic and elliptic design method.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a method for designing a bell mouth of a water inlet flow channel of a bidirectional pump station, which comprises the following steps:

modeling: the water inlet flow channel comprises a bell mouth, a water guide cone and a partition pier; the top surface of the partition pier is provided with the water guide cone; the bell mouth is sleeved outside the water guide cone;

segmenting: dividing the section line of the bell mouth into three sections: a first straight line, a parabola and a second straight line;

establishing a coordinate system: establishing a rectangular coordinate system at the center of the top surface of the bell mouth, writing out an equation of the parabola, and listing an equation set which the parabola should meet according to known geometric conditions;

establishing a formula: and solving an equation set to obtain the parabolic equation, and finally drawing the bell mouth molded line.

Preferably, in the modeling step, the bell mouth and the water guide cone are coaxially arranged; the small opening at the top end of the water guide cone is flush with the small opening at the top end of the bell mouth; and the bottom opening of the water guide cone is flush with the bottom surface of the partition pier.

Preferably, in the segmenting step, the parabola is connected between the first straight line and the second straight line, and is tangent to the first straight line and the second straight line respectively; the tangent points are respectively Q₁And Q₂。

Preferably, in the step of establishing a coordinate system, the center point of the outlet at the top of the bell mouth is taken as a circle center O, the horizontal direction is an X axis, and the vertical direction is a Y axis; the parabola is a quadratic parabola whose equation is:

Y＝aX²+bX+c

wherein a, b and c are coefficients to be solved;

and (3) listing an equation set according to the established coordinate system and the geometric relation:

wherein: x is the number of₀，y₀Is a tangent point Q₁Or Q₂The coordinates of (a); alpha is an included angle between the second straight line and the positive direction of the Y axis; d₀The diameter of the top surface of the bell mouth; d₁Is the diameter of the lowest point of the bell mouth; h is₀And tangent point Q₁Or Q₂Are equal in ordinate, h₁Is from the lowest point of the bell mouth to a tangent point Q₁Or Q₂Height in the Y direction of (a);

preferably, the coefficients of the parabolic equation obtained by solving the equation set are:

wherein: h is₂For the distance of bellmouth minimum Y to the height of separation mound bottom surface, H is bellmouth top surface to the height H of separation mound bottom surface: namely: h is₀+h₁+h₂＝H

And drawing the shape of the parabola according to the equation of the parabola, and drawing the second straight line, the parabola and the first straight line according to the geometric relationship, thereby designing the section profile line of the bell mouth.

The invention discloses the following technical effects:

the invention improves the design of hyperbolic and elliptical bell-mouth section molded lines of the water inlet flow passage of the original bidirectional pump station, realizes smooth molded line transition and improves the lift and the efficiency of the water pump.

The invention realizes the parametric design of the section profile line of the bell mouth, gives a specific execution formula of the design and improves the design efficiency of the bidirectional pump station.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a structure diagram of a water inlet channel of a bidirectional pump station.

Fig. 2 is a schematic view of the profile of a bell mouth of a water inlet channel of a bidirectional pump station.

The device comprises a horn mouth 1, a water guide cone 2, a partition pier 3, a first straight line 5, a second straight line 6 and a second straight line 7.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The invention provides a method for designing a bell mouth of a water inlet flow channel of a bidirectional pump station, which comprises the following steps:

modeling: the water inlet channel comprises a bell mouth 1, a water guide cone 2 and a partition pier 3; the top surface of the partition pier 3 is provided with a water guide cone 2; the bell mouth 1 is sleeved outside the water guide cone 2;

segmenting: the section line of the bell mouth 1 is divided into three sections: a first straight line 5, a parabola 6 and a second straight line 7;

establishing a coordinate system: a rectangular coordinate system is established at the center of the top surface of the bell mouth 1, an equation of the parabola 6 is written out, and an equation set which the parabola 6 should meet is listed according to known geometric conditions;

establishing a formula: and solving the equation set to obtain a parabola 6 equation, and finally drawing the molded line of the bell mouth 1.

In the further optimization scheme, in the modeling step, the bell mouth 1 and the water guide cone 2 are coaxially arranged; the small opening at the top end of the water guide cone 2 is flush with the small opening at the top end of the bell mouth 1; the bottom opening of the water guide cone 2 is flush with the bottom surface of the partition pier 3.

In the step of segmentation, a parabola 6 is connected between the first straight line 5 and the second straight line 7, and the parabola 6 is tangent to the first straight line 5 and the second straight line 7 respectively; the tangent points are respectively Q₁And Q₂。

In the step of establishing a coordinate system, the center point of an outlet at the top of the bell mouth 1 is taken as a circle center O, the horizontal direction is an X axis, and the vertical direction is a Y axis; then parabola 6 is a quadratic parabola whose equation is:

Y＝aX²+bX+c

wherein a, b and c are coefficients to be solved;

and (3) listing an equation set according to the established coordinate system and the geometric relation:

wherein: x is the number of₀，y₀Is a tangent point Q₁Or Q₂The coordinates of (a); alpha is an included angle between the second straight line 7 and the positive direction of the Y axis; d₀Is the diameter of the top surface of the bell mouth 1; d₁Is the diameter of the lowest point of the bell mouth 1; h is₀And tangent point Q₁Or Q₂Are equal in ordinate, h₁From the lowest point of the bell mouth 1 to the tangent point Q₁Or Q₂Height in the Y direction of (a);

further, in the above-mentioned case,

formula of system of equationsCan obtain

Formula of system of equationsCan obtain b ═ aD₁；

Formula of system of equationsAnd the formula b ═ aD₁Can obtain

X is to be₀And b into the first equation of the systemCan obtain

Further, the values of a are substituted into the relation b ═ aD₁Andthe coefficients a, b and c in the parabola 6 equation can be respectively obtained.

In a further optimization scheme, after an equation set is solved, coefficients of a parabola 6 equation are obtained as follows:

wherein: h is₂For the Y of horn mouth minimum distance bulkhead 3 bottom surfaces to the height, H is the height H of 1 top surface of horn mouth to 3 bottom surfaces of bulkhead: namely: h is₀+h₁+h₂＝H

The shape of the parabola 6 can be drawn by solving the equation of the parabola 6, and the second straight line 7, the parabola 6 and the first straight line 5 are drawn according to the geometric relationship, so that the section profile of the bell mouth 1 is designed.

Example 1:

fig. 1 shows a schematic structural diagram of a water inlet channel of a bidirectional pump station according to an embodiment, and the main parameters are as follows:

α＝10°、D₀＝292mm、D₁＝466mm

h₀＝156mm、h₂＝198mm、H＝460mm

determining a profile combination:

as shown in fig. 2, the profile of the bell mouth (1) is composed of a parabola (6) and two first straight lines (5) and (7), the parabola (6) is located in the middle of the first straight lines (5) and (7), and is tangent to the first straight line (5) and the second straight line (7) respectively;

establishing a coordinate system, and the following equation:

as shown in fig. 2, a rectangular coordinate system is established with the center point of the flow channel outlet as the center of the circle, the horizontal direction as the X axis, and the vertical direction as the Y axis.

Parabola (6) is a quadratic parabola, whose general form is listed:

Y＝aX²+bX+c

wherein a, b and c are coefficients to be solved.

And (3) listing an equation set according to the established coordinate system and the geometric relation:

solving an equation, and drawing a molded line:

substituting the structural parameters of the flow channel, solving an equation set to obtain the coefficients of a parabolic equation as follows:

the shape of the parabola can be drawn according to the equation of the parabola, and the second straight line (7), the parabola (6) and the first straight line (5) are drawn once according to the geometric relation, so that the section profile line of the bell mouth 1 is designed.

The molded line of the bell mouth of the original scheme adopts an elliptical design, and the design parameters are as follows:

Δ＝10°、D₀＝292mm、D₁＝466mm

h₀＝152mm、h₂198mm, 460mm, 209mm for the major and minor axes of the ellipse and 64mm for the minor axis of the ellipse.

As shown in table 1, the pump head and efficiency were increased by 7.34% and 3.26% at the design point, respectively, by comparison with the experimental data of the original scheme (elliptical design).

TABLE 1 comparison of test results

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.