阅读说明：本技术 一种离心泵叶轮叶片厚度的设计方法 (Design method for thickness of centrifugal pump impeller blade ) 是由 毛会文 王幼民 刘明伟 张天雨 许洪璐 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种离心泵叶轮叶片厚度的设计方法,包括包括前板盖、后板盖、叶片本体、吸水口和连接泵轴,所述前板盖的右侧设置有后板盖,且前板盖的内部安装有叶片本体,并且叶片本体的左侧设置有叶槽,所述吸水口开设于前板盖上,所述连接泵轴贯穿前板盖和后板盖,所述后板盖的外侧设置有轮毂。该离心泵叶轮叶片厚度的设计方法,在前人的研究基础上,设计叶片厚度,导出塑料离心泵叶片厚度的参考公式,有利于研究叶片轴向厚度变化对泵性能的影响,进而有利于指导设计更加合理的塑料离心泵叶轮叶片,利用该公式得到的叶片厚度比均匀设计的叶片在效率上提高1.2％,汽蚀余量减小,泵的整体性能提高。(The invention discloses a design method of the thickness of a centrifugal pump impeller blade, which comprises a front plate cover, a rear plate cover, a blade body, a water suction port and a connecting pump shaft, wherein the rear plate cover is arranged on the right side of the front plate cover, the blade body is arranged in the front plate cover, a blade groove is arranged on the left side of the blade body, the water suction port is formed in the front plate cover, the connecting pump shaft penetrates through the front plate cover and the rear plate cover, and a hub is arranged on the outer side of the rear plate cover. According to the design method for the thickness of the centrifugal pump impeller blade, on the basis of the research of predecessors, the thickness of the blade is designed, a reference formula of the thickness of the plastic centrifugal pump blade is derived, the influence of the axial thickness change of the blade on the performance of a pump is favorably researched, and further the more reasonable design of the plastic centrifugal pump impeller blade is favorably guided, the thickness of the blade obtained by the formula is improved by 1.2% in efficiency compared with the uniformly designed blade, the cavitation allowance is reduced, and the overall performance of the pump is improved.)

1. The utility model provides a centrifugal pump impeller, includes front bezel cover (1), back plate cover (2), blade body (3), water sucking mouth (5) and connection pump shaft (7), its characterized in that: the right side of front bezel lid (1) is provided with back bezel lid (2), and the internally mounted of front bezel lid (1) has blade body (3) to the left side of blade body (3) is provided with leaf groove (4), water sucking mouth (5) are seted up on front bezel lid (1), connection pump shaft (7) run through front bezel lid (1) and back bezel lid (2), the outside of back bezel lid (2) is provided with wheel hub (6).

2. A centrifugal pump impeller according to claim 1, wherein: the pump is characterized in that the front plate cover (1) and the rear plate cover (2) are of an integral structure, the rear plate cover (2) is connected with the pump shaft (7) in a bearing mode, and the water suction port (5) in the front plate cover (1) is of a circular structure.

3. A centrifugal pump impeller according to claim 1, wherein: the blade body (3) and the connection mode of connecting pump shaft (7) are the welding, and blade body (3) is on the equal angular distribution of outer wall of connecting pump shaft (7) to there is the interval between blade body (3) and front bezel cover (1), and blade body (3) are the arc structure simultaneously.

4. A centrifugal pump impeller according to claim 1, wherein: the hub (6) is connected with the rear plate cover (2) through a bearing, and the hub (6) is connected with the connecting pump shaft (7) through welding.

5. A design method for the thickness of a centrifugal pump impeller blade is characterized by comprising the following steps: the method comprises the following steps:

the first step is as follows: firstly, designing a plastic centrifugal pump impeller blade body (3), establishing a coordinate system to design the thickness of the blade body (3) according to the characteristics of the plastic centrifugal pump, obtaining the thickness change of the blade body (3), and pushing out a reference formula of the thickness of the plastic centrifugal pump blade body (3);

the second step is that: through flow field analysis and simulation, the fact that compared with the blade body (3) which changes uniformly, the stress strain of the variable-thickness impeller is smaller, meanwhile, the efficiency of the pump is improved, the cavitation allowance is reduced, and the overall performance of the pump is improved;

the third step: the maximum thickness of the blade body (3) is moved forwards, the entrance angle of the back of the blade body (3) is reduced, the impact loss can be effectively reduced, meanwhile, the thickness of the blade body (3) is designed to be changed in an arc shape, fluid can flow to the trailing edge along the surface without separation as much as possible, the flow loss of the fluid at the trailing edge of the blade body (3) is reduced, and the working efficiency of the plastic centrifugal pump is improved;

the fourth step: the front end of the blade body (3) is designed by utilizing an elliptic arc, the front edge of the blade body (3) has large influence on a pump, the thickness of the front edge of the blade body (3) is slowly changed, which is favorable for improving the performance of the plastic centrifugal pump, the thickness of the front edge of the blade body (3) is slowly changed, and the thickness of the tail blade of the blade body (3) is reduced, so that the serious cavitation caused by the overlarge thickness of the tail part is avoided, the maximum thickness is moved forward to ensure that the pressure distribution on the blade body (3) is more uniform, and an unstable area is mainly in the front half section;

the fifth step: expand evenly changed's blade body (3) along the bone line, obtain original blade body (3) geometric figure, expand original blade body (3) in bone line n direction, blade body (3) front end is the circular arc connection of radius for r, and later thickness evenly increases to the tail end, and vertical direction is thickness t, utilizes the following relational expression of geometric mathematics knowledge can be obtained:

the increment in the thickness t direction from the point N to the point M is

Is simplified to obtain

Designing the curve of the impeller blade body (3) on the basis of the curve of the original blade body (3), solving the undetermined coefficient of the curve of the impeller blade body (3) to obtain the change rule of the blade body (3),

the quartic spline curve of the blade thickness equation is designed as:

in the formula: t is t_m-maximum blade thickness (mm);

k-chord length ratio

Solving the normal equation set to obtain the values of coefficients a, b, c, d and e of a quartic spline curve relational expression of the blade thickness equation, and deriving a reference formula of the blade thickness of the plastic centrifugal pump;

and a sixth step: after a reference formula of the thickness of the blade body (3) is obtained, a fluid model and an impeller solid model are designed, internal flow field simulation is carried out, the fact that the axial vortex phenomenon of the internal flow of the pump basically disappears is found, the internal flow is more stable, the speed of the back of the inlet of the blade body (3) is higher, the speed near a partition tongue area is increased rapidly, and the internal flow field simulation accords with normal conditions.

Technical Field

The invention relates to the technical field of plastic centrifugal pumps, in particular to a design method for the thickness of a centrifugal pump impeller blade.

Background

The plastic centrifugal pump is widely applied to the transportation of corrosive materials such as chemical engineering, petroleum and the like with the advantages of outstanding corrosion resistance, light weight, low price and the like, and along with the continuous increase of the utilization rate of the plastic centrifugal pump, the performance requirement on the pump is higher and higher.

The thickness of the blade is an important structural parameter influencing the performance of the plastic centrifugal pump, the flow channel is narrowed when the thickness of the blade is too large, the relative speed of fluid in the flow channel is increased, and the hydraulic loss is increased; and the thickness of the blade is reduced to widen the flow passage, and the slip coefficient is reduced, thereby improving the efficiency of the plastic centrifugal pump. Due to the material characteristics of the plastic centrifugal pump, the continuous reduction of the thickness can cause the condition that the pump cannot work normally due to the fact that the impeller is deformed too much due to insufficient strength. In the existing research, the thickness value is irregular and can be circulated, inconvenience is brought to designers, in order to research the influence of the thickness of the blades of the plastic centrifugal pump on the performance of the pump, a formula can be found like a design manual, and based on the research results of the blades with the equal thickness and the variable thickness of the blades of the centrifugal pump, a reference formula of the thickness of the blades of the plastic centrifugal pump is pushed out for the designers to refer to.

Disclosure of Invention

The invention aims to provide a design method of the thickness of a centrifugal pump impeller blade, which aims to solve the problems that the influence of different thicknesses of the existing plastic centrifugal pump blades on the flow speed is different, and the inconvenience is brought to designers due to the irregular value of the blade thickness in the existing research.

In order to achieve the purpose, the invention provides the following technical scheme: the design method of the thickness of the centrifugal pump impeller blade comprises a front plate cover, a rear plate cover, a blade body, a water suction port and a connecting pump shaft, wherein the rear plate cover is arranged on the right side of the front plate cover, the blade body is arranged inside the front plate cover, a blade groove is formed in the left side of the blade body, the water suction port is formed in the front plate cover, the connecting pump shaft penetrates through the front plate cover and the rear plate cover, and a hub is arranged on the outer side of the rear plate cover.

Preferably, the front plate cover and the rear plate cover are of an integrated structure, the rear plate cover is connected with the pump shaft through a bearing, and the water suction port in the front plate cover is of a circular structure.

Preferably, the connection mode of blade body and connection pump shaft is the welding, and the blade body is equidistance on the outer wall of connection pump shaft to there is the interval between blade body and the front bezel cover, and the blade body is arc structure simultaneously.

Preferably, the hub and the rear plate cover are connected through a bearing, and the hub and the connecting pump shaft are connected through welding.

Preferably, the voltage acquisition port, the current acquisition port and the acousto-optic alarm are electrically connected with the single chip microcomputer.

A design method for the thickness of a centrifugal pump impeller blade comprises the following steps:

the first step is as follows: firstly, designing a blade body of a plastic centrifugal pump impeller, establishing a coordinate system to design the thickness of the blade body according to the characteristics of the plastic centrifugal pump, obtaining the thickness change of the blade body, and pushing out a reference formula of the thickness of the blade body of the plastic centrifugal pump;

the second step is that: through flow field analysis and simulation, the fact that compared with a blade body which changes uniformly, the stress strain of the variable-thickness impeller is smaller, meanwhile, the efficiency of the pump is improved, the cavitation allowance is reduced, and the overall performance of the pump is improved;

the third step: the maximum thickness of the blade body is moved forward, the entrance angle of the back of the blade body is reduced, the impact loss can be effectively reduced, meanwhile, the thickness of the blade body is designed to be changed in an arc shape, fluid can flow to the trailing edge along the surface without separation as much as possible, the flow loss of the fluid at the trailing edge of the blade body is reduced, and the working efficiency of the plastic centrifugal pump is improved;

the fourth step: the front end of the blade body is designed by utilizing an elliptical arc, the front edge of the blade body has large influence on the pump, the thickness change of the front edge of the blade body is slow, which is favorable for improving the performance of the plastic centrifugal pump, the thickness change of the front edge of the blade body is slow, the thickness of the blade at the tail part of the blade body is reduced, so that the serious cavitation caused by the overlarge thickness of the tail part is avoided, the maximum thickness is moved forward to ensure that the pressure distribution on the blade body is more uniform, and the unstable area is mainly in the front half section;

the fifth step: unfolding the uniformly-changed blade body along the bone line to obtain the geometric figure of the original blade body, unfolding the original blade body in the direction of the bone line n, connecting the front end of the blade body by an arc with the radius of r, uniformly increasing the thickness of the blade body to the tail end, and vertically increasing the thickness of the blade body by the thickness t,

the following relation can be obtained by using geometrical mathematical knowledge:

the increment in the thickness t direction from the point N to the point M is

Is simplified to obtain

Designing the curve of the impeller blade body 3 based on the curve of the original blade body 3, solving the undetermined coefficient of the curve of the impeller blade body 3 to obtain the change rule of the blade body 3,

the quartic spline curve of the blade thickness equation is designed as:

in the formula: t is t_m-maximum blade thickness (mm);

k-chord length ratio

Designing a curve of an impeller blade body on the basis of a curve of an original blade body, solving undetermined coefficients of the curve of the impeller blade body to obtain a change rule of the blade body, solving the normal equation set to obtain values of coefficients a, b, c, d and e of a quartic spline curve relational expression of a blade thickness equation, and deriving a reference formula of the blade thickness of the plastic centrifugal pump;

and a sixth step: after a reference formula of the thickness of the blade body is obtained, a fluid model and an impeller solid model are designed, internal flow field simulation is carried out, the fact that the axial vortex phenomenon of the internal flow of the pump basically disappears is found, the internal flow is more stable, the speed of the back of the inlet of the blade body is higher, the speed near a partition tongue area is increased rapidly, and the blade body conforms to the normal condition.

Compared with the prior art, the invention has the beneficial effects that: the design method of the thickness of the impeller blade of the centrifugal pump;

(1) based on the research results of the equal thickness and the variable thickness of the impeller blade of the plastic centrifugal pump, on the basis of the research of the predecessors, the thickness of the blade is designed, a reference formula of the thickness of the blade of the plastic centrifugal pump is derived, the research on the influence of the axial thickness change of the blade on the performance of the pump is facilitated, and the guidance on designing the more reasonable impeller blade of the plastic centrifugal pump is facilitated;

(2) the blade body sets up to the arc form, and is welded connection between blade body and the connection pump shaft to there is the interval between blade body and the front bezel lid, like this in the use, can accelerate the velocity of flow of liquid, and then has improved centrifugal pump's work efficiency, has also improved the performance of this centrifugal pump.

Drawings

FIG. 1 is a schematic view of an overall main sectional structure of the present invention;

FIG. 2 is a schematic diagram of the side view of the interior of the front cover of the present invention;

FIG. 3 is a schematic view of the original two-dimensional blade profile expanded configuration of the present invention;

fig. 4 is a graph of the thickness variation of the present invention.

In the figure: 1. a front plate cover; 2. a rear plate cover; 3. a blade body; 4. a leaf groove; 5. a water suction port; 6. a hub; 7. and a pump shaft is connected.

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.

Referring to fig. 1-4, the present invention provides a technical solution: the design method of the thickness of the centrifugal pump impeller blade comprises a front plate cover 1, a rear plate cover 2, a blade body 3, a blade groove 4, a water suction port 5, a hub 6 and a connecting pump shaft 7, wherein the rear plate cover 2 is arranged on the right side of the front plate cover 1, the blade body 3 is arranged inside the front plate cover 1, the blade groove 4 is arranged on the left side of the blade body 3, the water suction port 5 is formed in the front plate cover 1, the connecting pump shaft 7 penetrates through the front plate cover 1 and the rear plate cover 2, and the hub 6 is arranged on the outer side of the rear plate cover 2.

Front bezel cover 1 and 2 formula structures as an organic whole of back bezel cover, and back bezel cover 2 is connected for the bearing with the connected mode of connecting pump shaft 7, and water sucking mouth 5 on the front bezel cover 1 is circular structure, can make the more firm of being connected between front bezel cover 1 and the back bezel cover 2, effectively prevent the phenomenon that the not hard up droing from appearing in the use, and the setting of water sucking mouth 5 can make this impeller normally inhale liquid, increases the suction area of liquid, ensures the normal clear of whole operation.

The connected mode of blade body 3 and connection pump shaft 7 is the welding, and blade body 3 equidistance on the outer wall of connecting pump shaft 7, and there is the interval between blade body 3 and front bezel cover 1, blade body 3 is the arc structure simultaneously, can make blade body 3 and connect the fastening more of being connected between the pump shaft 7, when connecting pump shaft 7 rotatory like this, can drive blade body 3 and rotate together, inhale liquid through blade body 3, the processing operation in the later stage of being convenient for, and the design of the blade body 3 of arc form, can make the liquid velocity of flow obtain improving, thereby improve the work efficiency of this plastics centrifugal pump.

The connected mode of wheel hub 6 and back plate cover 2 is the bearing connection, and wheel hub 6 and the connected pump shaft 7's connected mode be the welding, has guaranteed the stability of being connected between wheel hub 6 and the back plate cover 2, also makes wheel hub 6 and connect more firm of being connected between the pump shaft 7, does not influence the normal rotation of connecting pump shaft 7 simultaneously, and then makes whole operation go on in order, has further guaranteed the overall stability when this centrifugal pump uses.

A design method for the thickness of a centrifugal pump impeller blade is characterized by comprising the following steps: the method comprises the following steps:

the first step is as follows: firstly, designing a plastic centrifugal pump impeller blade body 3, establishing a coordinate system to design the thickness of the blade body 3 according to the characteristics of the plastic centrifugal pump, obtaining the thickness change of the blade body 3, and pushing out a reference formula of the thickness of the plastic centrifugal pump blade body 3;

the second step is that: through flow field analysis and simulation, the fact that compared with the blade body 3 which changes uniformly, the stress strain of the variable-thickness impeller is smaller, meanwhile, the efficiency of the pump is improved, the cavitation allowance is reduced, and the overall performance of the pump is improved;

the third step: the maximum thickness of the blade body 3 is moved forward, the entrance angle of the back of the blade body 3 is reduced, the impact loss can be effectively reduced, meanwhile, the thickness of the blade body 3 is designed to be changed in an arc shape, fluid can flow to the trailing edge along the surface without separation as much as possible, the flow loss of the fluid at the trailing edge of the blade body 3 is reduced, and the working efficiency of the plastic centrifugal pump is improved;

the fourth step: the front end of the blade body 3 is designed by utilizing an elliptic arc, the influence of the front edge of the blade body 3 on the pump is large, the slow thickness change of the front edge of the blade body 3 is favorable for improving the performance of the plastic centrifugal pump, the slow thickness change of the front edge of the blade body 3 is designed, the thickness of the blade at the tail part of the blade body 3 is reduced, so that the serious cavitation caused by the overlarge thickness of the tail part is avoided, the maximum thickness is moved forwards, and the unstable area is mainly in the front half section in order to ensure that the pressure distribution on the blade body 3 is more;

the fifth step: expand uniform variation's blade body 3 along the bone line, obtain 3 geometric figure of original blade body, expand original blade body 3 in bone line n direction, and 3 front ends of blade body are connected for the circular arc of radius r, and later thickness evenly increases to the tail end, and vertical direction is thickness t, utilizes geometry mathematical knowledge can obtain following relational expression:

the processes used in the first step are as follows:

the increment in the thickness t direction from the point N to the point M is

Is simplified to obtain

Designing the curve of the impeller blade body 3 based on the curve of the original blade body 3, solving the undetermined coefficient of the curve of the impeller blade body 3 to obtain the change rule of the blade body 3,

the quartic spline curve of the blade thickness equation is designed as:

in the formula: t is t_mMaximum blade thickness mm

k-chord length ratio

Solving the normal equation set to obtain the values of coefficients a, b, c, d and e of a quartic spline curve relational expression of the blade thickness equation, and deriving a reference formula of the blade thickness of the plastic centrifugal pump;

and a sixth step: after a reference formula of the thickness of the blade body 3 is obtained, a fluid model and an impeller solid model are designed, internal flow field simulation is carried out, the fact that the axial vortex phenomenon of the internal flow of the pump basically disappears is found, the internal flow is more stable, the speed of the back of the inlet of the blade body 3 is higher, the speed near a partition tongue area is increased rapidly, and the normal situation is met.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Examples of the design

And step one, solving the normal equation set to obtain the values of coefficients a, b, c, d and e of the quartic spline curve of the blade thickness equation, and deriving a reference formula of the blade thickness of the plastic centrifugal pump. The method comprises the following specific steps:

as shown in fig. 3, the optimization process is performed on the shape of the original blade, and the front end of the blade is designed to be a parabola, and then is changed by a curve, and the curve is increased to the maximum thickness and then reduced. According to the geometric shape of the original blade, the geometric operation is carried out to obtainThen n_MN0.209mm, slope at tangent pointThe chord length c of the designed blade profile is 144.4mm, the front end of the blade occupies about 0.04c, and the reason that the difference is not large when cavitation analysis is carried out is that the inlet thickness of the impeller is 4mm, so that the geometric models of the front end of the blade are almost the same, circular arc fitting is utilized, the diameter fluctuates around 4mm, and the inlet thickness of the blade is designed to be 4mm according to the minimum blade thickness in the design of equal thickness.

The thickness change can not be too fast when the front edge of the blade is designed, the front edge of the blade is positioned at 0.04 c-0.2 c of the molded line of the blade, and in order to ensure the requirements, the change slope of the blade at 0.04c is takenThe thickness of the blade is uniformly increased, the speed tends to be stable, the pressure is also distributed circumferentially,

and (3) designing a curve of the impeller blade, establishing a coordinate system by taking the point A as a coordinate origin according to the characteristics of the plastic centrifugal pump, and designing a blade thickness rule.

The quartic spline curve of the blade thickness equation is designed as:

in the formula: t is t_mMaximum blade thickness (mm)

k-chord length ratio

The first derivative of the thickness t with respect to the chord length ratio k is:

at the coordinate origin, according to the analysis result of the equal thickness variation, the thickness at the inlet is 4mm, i.e. the coordinate at the coordinate origin is (0, ± 2), then f is 2; the ratio of the front edge of the blade is 0.04c, the thickness of the front edge is about 4mm, basically no change occurs, and the slope at 0.04c isNamely:

design blade leading edge thickness variation slowly, blade afterbody blade thickness reduces to avoid afterbody thickness too big and cause the cavitation serious, for guaranteeing that the pressure distribution on the blade is more even, with maximum thickness antedisplacement, unstable area is mainly at first half section, therefore we fix a position k with maximum thickness for the position of 0.6c, maximum thickness t_mTaking 8mm here, the coordinate at maximum thickness is (0.6, ± 4), the slope at that point is 0, i.e.The equation is obtained as follows:

the thickness of the blade tail is designed according to the minimum thickness,the thickness gradually decreases from 0.6c to c, and the thickness of the blade is 4mm at the tail part of the blade. Calculating the values of a, b, c, d, e according to the above conditions, the following equations can be listed:

will have a maximum thickness t_mSubstituting 8mm into the above formula and simplifying to obtain the following equation

The coefficient matrix A is then

Solving an equation set by using Matlab software to obtain solutions of a, b, c, d and e:

the solution equation is:

the value of k can be 0-1, the equation image is shown in figure 4, the thickness change of the front edge of the blade is relatively slow, and meanwhile, in order to improve the cavitation resistance of the plastic centrifugal pump, the original circular arc fitting is replaced by a parabola shape on the front edge of the blade. In summary, the variation of the blade thickness from the inlet end to the outlet end is as follows:

software analysis shows that the blade thickness obtained by the formula is improved by 1.2 percent in efficiency compared with the blade with uniform design, the cavitation allowance is reduced, the overall performance of the pump is improved, and the axial vortex phenomenon in internal flow is basically eliminated.

In summary, the formula of the blade thickness variation rule derived from the above formula is consistent with the expected result, and can be referred to as a design formula when designing the plastic centrifugal pump.