KR101807418B1 - Optimal design method of impeller and diffuser, impeller and diffuser designed by the method and centrifugal and mixed flow pump having the same - Google Patents

Abstract

Provided is an optimized design method of an impeller and a diffuser. The optimized design method of an impeller and a diffuser optimizes an impeller and a diffuser at the same time, which is connected to the impeller and discharges a fluid introduced through the impeller, at the same time to simultaneously satisfy a head and improve efficiency. The optimized design method of the impeller and the diffuser comprises: a step of determining a design variable and an objective function in consideration of the shape of the impeller and the diffuser; a step of determining a major design variable which affects a value of the objective function; a step of identifying an optimum design variable condition to optimize the value of the objective function; and a step of deriving the optimized shape of the impeller and the diffuser using a response surface method with the optimum design variable condition.

Description

TECHNICAL FIELD The present invention relates to an optimum design method of an impeller and a diffuser for simultaneously optimizing efficiency and heading, an impeller and a diffuser designed thereby, and a centrifugal and differential pump having the impeller and the diffuser. PUMP HAVING THE SAME}

The present invention relates to an optimum design method of an impeller and a diffuser which simultaneously optimize efficiency and heading, a designed impeller and diffuser, and a centrifugal and multistage pump having the same.

Pumps are used in the transportation of fluids in general households and industries, and in various plant industries (such as chemical, nuclear power, power plants and offshore plants). There are various pumps depending on the requirements.

Centrifugal and multistage pumps refer to fluid machines that generate a pump action, that is, a fluid transport action or a pressure, by using a centrifugal force generated by an impeller that is rotated by receiving power from the outside.

Generally, an impeller is a main component such as a turbo-type pump, a blower or a compressor. The impeller is composed of several to several tens of wings arranged at equal intervals on a circumference, and a disk integrally attached to cover one side of the wing.

Fluids such as air, water, and oil flow through the vanes of the impeller rotating at a high speed by a prime mover, and the impeller is divided into centrifugal type, cascade type and axial flow type have.

At this time, the centrifugal impeller causes the fluid to flow in a direction perpendicular to the rotation axis, that is, in the direction from the center to the outer circumference of the circle, and the axial flow impeller flows mainly in the direction of the rotation axis. The type is an intermediate type of centrifugal type and axial flow type, and the fluid flowing in the direction of the axis of rotation of the impeller flows in an oblique direction to the rotating shaft.

In the conventional centrifugal and extruder pumps, the design of the diffuser has been designed after the impeller has been designed, and the design of the diffuser has been limited while the shape of the impeller has been fixed.

An embodiment of the present invention is to provide an optimum design method of an impeller and a diffuser that can improve efficiency and satisfy an accurate heading, an impeller and a diffuser designed thereby, and a centrifugal and hydrodynamic pump having the impeller and the diffuser.

According to an aspect of the present invention, the shape of the impeller and the diffuser may be considered to optimize the diffuser, which is connected to the impeller and the impeller, through which the fluid introduced through the impeller is discharged to the outside, Determining a design variable and an objective function; Determining a main design variable that affects a value of the objective function; An optimal design parameter condition grasping step of optimizing the value of the objective function and an optimizing design method of an impeller and a diffuser including an optimization shape deriving step of the impeller and the diffuser by using a reaction surface technique with the optimal design parameter condition .

At this time, in consideration of the shape of the impeller and the diffuser, the specific speed is determined by a flow quantity (Q), a heading (Ht) and a rotational speed (N) which are design specifications, and the specific speed is 150 To 1200 Ns.

In this case, the objective function may be a head (Ht) and an efficiency (? T) for analyzing the performance of the impeller and the diffuser in the design parameters and the objective function determination in consideration of the shape of the impeller and the diffuser.

The determining of the design variables of the impeller and the diffuser may include: determining an impeller meridional surface design parameter expressing a shape of the impeller blade to generate a three-dimensional shape of the impeller; A diffuser meridional surface design parameter determination step of expressing a shape of a blade of the diffuser to generate a three-dimensional shape of the diffuser; Determining the design variables of the impeller blade angle expressing the blade angle of the impeller and determining the design variables of the diffuser blade angle expressing the blade angle of the diffuser.

At this time, in the impeller meridian design parameter determination step, the meridional surface design parameter of the impeller has a radius R1_h of the hub portion at the inlet portion of the impeller, a radius R1_s of the shroud portion at the inlet portion of the impeller, A diameter R2 of the impeller outlet, a blade width b2 at a trailing edge of the impeller blade, a tilted angle 2 of the rear end of the impeller blade, a shroud inlet port and an outlet port, And a length Ztip in the axial direction.

At this time, the meridional surface design parameters of the impeller include an inlet angle and an outlet angle (? 1_s,? 2_s) formed by the Shroud curve of the impeller with a horizontal line and a vertical line, an inlet angle and an outlet angle with the hub curve of the impeller, (% L_h,% L_s) of the straight portion in the impeller outlet hub and the shroud, a shroud inlet for generating a Bezier curve from the point where the straight section of the outlet ends to the impeller inlet, (CP1_s,% CP2_s) and the hub inlet adjustment point and the outlet adjustment point (% CP1_h,% CP2_h).

(H, m, s), the exit start point TE start point, the sweep angle of the impeller and the averaged radius, r_theta_total_ (h, m, s) (H, m, s), the exit angle beta2_ (h, m, s), the length of the inlet straight line portion% beta_LE_ (H, m, s) of the entrance portion and an adjustment point% CP_TE_ (h, m, s) of the exit portion in the rotation direction at the exit portion .

At this time, in the meridional surface design parameter determination step of the diffuser, the meridional surface design parameters of the diffuser are determined such that the radius R3_h of the hub portion at the diffuser inlet portion, the blade width b3 at the front end of the diffuser blade, ), The radius at the diffuser outermost point (R4h), the blade width at the diffuser outermost point (b4), the tilted angle at the outermost diffuser point (4), the radius at the diffuser exit (R5h) The inclination angle? 5 at the diffuser outlet, the hub side diffuser inlet adjustment point CP1h, the first and second diffuser outermost point adjustment points CP2h and CP2h at the hub side, The diffuser inlet portion (% CP3h), the hub-side diffuser outlet adjusting portion (% CP4h), the angle? 1h formed by the hub curve at the diffuser inlet portion with the horizontal line, the angle? 4h formed by the hub curve at the diffuser outlet portion with the horizontal line, Adjustment point (% CP1s), 1st and 2nd diffuser angles on the shroud side (% CP2s,% CP3s), the diffuser outlet adjustment point (% CP4s) at the shroud side, the angle (θ1s) the Shroud curve of the diffuser inlet with the horizontal line, and the shroud curve at the diffuser exit And an angle [theta] 4s formed between them.

At this time, in the blade design parameter determination step of the diffuser, the blade development design parameter includes a TE start point, a product of a sweep angle of the diffuser and a mean radius (r_theta_total), an entrance angle (beta1_ (h, m, s) ), The exit angle (beta2_ (h, m, s)), the length of the entrance rectilinear section (beta_LE_ (h, m, s) (H, m, s) of the exit portion and an inclination angle (d_theta (h, s)) inclined in the rotation direction, an adjustment point (CP_LE_ can do.

At this time, in the main design parameter determining step, which affects the design objective value, the main design parameter includes an exit angle (i_beta2_h) of the impeller hub, an exit angle (i_beta2_s) of the impeller shroud, An inlet angle d_beta1_h of the diffuser hub, and an inlet angle d_beta1_s of the diffuser shroud.

At this time, the remaining design variables other than the main design variables can be fixed to optimal values from the results obtained through the 2 ^k factorial designs and the response surface method.

At this time, in the step of grasping the condition of the optimal design variable capable of optimizing the objective function value, the specific speed is the same, the starting point S1_h of the inlet hub is fixed to the same axis C2 in the radial direction, The inner diameter R1_h of the hub portion at the inlet portion is the same and the inner diameter R1_s of the shroud portion at the inlet portion is equal to the outer diameter of the shroud curve of the impeller The entrance angle? 1_s formed between the horizontal line and the vertical line can be fixed to be the same.

At this time, the exit angle (i_beta2_h) of the impeller hub is in the range of 27 to 35 degrees and the exit angle (i_beta2_s) of the impeller shroud is in the range of 12 to 20 , The entrance angle (d_beta1_h) of the diffuser hub may be between 139 degrees and 147 degrees, and the entrance angle (d_beta1_s) of the diffuser shroud may be between 146 degrees and 154 degrees.

In the derivation of the optimized shape of the impeller and the diffuser using the reaction surface method with the optimum design parameter condition, the impeller hub exit angle i_beta2_h satisfying the heading and the efficiency simultaneously using the reaction surface technique, The impeller shroud exit angle (i_beta2_s), the diffuser hub inlet angle (d_beta1_h), and the diffuser shroud inlet angle (d_beta1_s).

According to another aspect of the present invention, there is provided an impeller and a diffuser designed by the above-described optimum design method of the impeller and the diffuser.

According to another aspect of the present invention, there is provided an impeller and a diffuser as described above; And a casing having the impeller installed therein and having an inlet formed to suck the fluid toward the front of the impeller and an outlet formed to discharge the sucked fluid to the outer periphery of the impeller.

The impeller and diffuser designed method, the impeller and the diffuser, and the centrifugal and extruder pumps having the impeller and the diffuser designed according to the embodiment of the present invention are designed to simultaneously improve the efficiency and satisfy the accurate heading by simultaneously designing the impeller outlet portion and the diffuser inlet portion. have.

In addition, the optimum design method of the impeller and the diffuser according to the embodiment of the present invention can shorten the time for designing the shape of the impeller and the diffuser by using the design of experiment.

FIG. 1 is a flowchart illustrating an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
2 is a cross-sectional view of a centrifugal and hydrostatic pump having an impeller and a diffuser designed according to an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
3 is a plan view of an impeller designed according to an optimal design method of an impeller and a diffuser according to an embodiment of the present invention.
4 is a plan view of a diffuser designed according to an optimal design method for an impeller and a diffuser according to an embodiment of the present invention.
5 is a cross-sectional view illustrating a meridional plane of an impeller designed according to an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
FIG. 6 is a schematic view illustrating design variables of blade angle of an impeller in an optimal design method of an impeller and a diffuser according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view illustrating a meridional plane of a diffuser in an optimum design method for an impeller and a diffuser according to an embodiment of the present invention.
FIG. 8 is a schematic view showing design variables of a blade angle of a diffuser in an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
FIG. 9 is a schematic view showing major design parameters of impeller blades in an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
10 is a schematic view showing main design variables of the blade angle of the diffuser in the method of optimizing the design of the impeller and the diffuser according to the embodiment of the present invention.
11 is a graph according to a reaction optimization technique in an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.
12 is a perspective view illustrating numerical analysis boundary conditions and a lattice system of an impeller and a diffuser designed by an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, where a section such as a layer, a film, an area, a plate, or the like is referred to as being "on" another section, it includes not only the case where it is "directly on" another part but also the case where there is another part in between. On the contrary, where a section such as a layer, a film, an area, a plate, etc. is referred to as being "under" another section, this includes not only the case where the section is "directly underneath"

FIG. 1 is a flowchart illustrating an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.

Referring to FIG. 1, the method for optimizing an impeller according to an embodiment of the present invention includes a design parameter selection and an objective function determination step (S10) in consideration of shapes of an impeller and a diffuser, (S30) for optimizing the objective function value, and deriving an optimized shape of the impeller and the diffuser using the reaction surface technique at the optimum design parameter condition S40).

Accordingly, the optimum design method of the impeller and the diffuser according to the embodiment of the present invention can simultaneously improve the efficiency and satisfy the accurate heading by simultaneously designing the inlet of the impeller 10 and the inlet of the diffuser 5.

2 is a cross-sectional view of a centrifugal and hydrostatic pump having an impeller and a diffuser designed according to an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.

2, the suction port 3 of the centrifugal and extruder pumps is defined forward from the drive shaft 30 of the motor and the suction port 3 of the centrifugal and extruder pumps is connected to the drive shaft 30 side of the motor Rear direction.

2, a centrifugal and hydrostatic pump 1 according to an embodiment of the present invention may include an impeller 10, a casing 2, and a diffuser 5 designed by an impeller and diffuser-optimized design method .

At this time, a centrifugal and extrusion pump impeller 10 for sucking and discharging the fluid while rotating at a high speed between the suction port 3 and the discharge port (not shown) may be incorporated in the centrifugal and extrusion pump 1.

2, in an embodiment of the present invention, the impeller 10 and the diffuser 5 of the centrifugal and multistage pumps may be installed in the casing 2. In addition, a suction port 3 through which the fluid is sucked is formed in the front center portion of the centrifugal and extruder pump impeller 10, and a sucked fluid is discharged to the outer circumferential portion of the centrifugal and extruder pump impellers in a radial direction.

At this time, in one embodiment of the present invention, the diffuser 5 may be formed with a discharge port so that the fluid introduced through the impeller 10 is discharged to the outside.

3 is a plan view of an impeller designed according to an optimal design method of an impeller and a diffuser according to an embodiment of the present invention.

3, the impeller 10 designed according to the method of optimizing the design of the impeller and the diffuser according to an embodiment of the present invention includes the impeller hub 11, the impeller blade 13, and the impeller shroud 15 .

2 and 3, in an embodiment of the present invention, the impeller hub 11 is coupled to the motor drive shaft 30 and receives the rotational force of the motor. The impeller hub 11 has a high rigidity suitable for high- .

At this time, the impeller hub 11 may be formed to have a conical shape in which the cross-sectional area is reduced while moving backward. That is, the hub 11 is formed at the center of the impeller 10, and the driving shaft 30 is coupled to the impeller hub, so that the rotational force of the motor can be transmitted to the impeller 10.

2 and 3, a plurality of impeller blades 13 may be radially formed on the circumferential surface of the impeller hub 11 as a center. At this time, the plurality of impeller blades 13 may be composed of five, but the embodiment of the present invention is not limited thereto.

The impeller shroud 15 may be formed to surround the entire outer end of the impeller blade 13 while connecting the outer ends of the plurality of impeller blades 13 disposed in the impeller hub 11. This impeller shroud 15 can be connected to each of the impeller blades 13.

4 is a plan view of a diffuser designed according to an optimal design method for an impeller and a diffuser according to an embodiment of the present invention.

4, the diffuser 5 designed according to the method of optimizing the design of the impeller and the diffuser according to the embodiment of the present invention includes the diffuser hub 7, the diffuser blade 6 and the diffuser shroud 9 .

2 and 4, in the embodiment of the present invention, the diffuser hub 7 is installed at the rear end of the impeller 10 to diffuse the fluid when discharging the fluid discharged through the impeller to the outside Speed and pressure can be converted.

At this time, the diffuser hub 7 may be formed so as to have an arc shape having a curved sectional area while moving backward. That is, the hub 11 is formed in the circumferential portion of the diffuser 5, and the impeller 10 is coupled to the hub, and the fluid discharged through the impeller can be transferred to the diffuser hub 7.

2 and 4, a plurality of diffuser blades 6 may be radially formed on the circumferential surface of the diffuser hub 7 as a center. At this time, the plurality of diffuser blades 6 may be composed of seven, but the embodiment of the present invention is not limited thereto.

The diffuser shroud 9 may also be formed to enclose the entire outer end while connecting the outer ends of a plurality of diffuser vanes 6 disposed in the diffuser hub 7. [ This diffuser shroud 9 can be connected to each diffuser wing 6.

Referring to FIG. 1, an optimal design method of an impeller and a diffuser according to an embodiment of the present invention may include a design parameter selection and an objective function determination step (S10) in consideration of shapes of an impeller and a diffuser.

In consideration of the shape of the impeller and the diffuser, the flow rate Q, the head Ht and the flow rate Q are required in design parameter selection and objective function determination step S10 in designing the impeller 10 and the diffuser 5, The number of revolutions N can be determined. The flow specifications Q, the head Ht and the number of revolutions N are specifications required for designing the impeller 10 and the diffuser 5.

At this time, the flow rate Q and the head Ht are basically satisfactory specifications while the impeller 10 rotates, and the rotation speed N can be determined according to the diameter of the motor drive shaft 30.

On the other hand, the impeller 10 and the diffuser 5 can be designed to have the highest efficiency at a given flow rate and head. That is, since both the impeller 10 and the diffuser 5 are simultaneously designed to optimize the efficiency and heading simultaneously, the blade shape and the meridional surface shape of the impeller and the diffuser can be mutually changed.

Therefore, in order to analyze the performance of the impeller and the diffuser according to the design parameters considering the shape of the impeller and the diffuser, the objective function for the design purpose should be defined. At this time, the objective function for the design purpose may be the pump efficiency and the head pump showing the performance of the impeller and the diffuser.

Meanwhile, in one embodiment of the present invention, the type of the pump can be determined by determining the specific speed in the design parameter selection and the objective function determination step (S10) in consideration of the shape of the impeller and the diffuser. In the example, the type of the pump may be a centrifugal pump and a centrifugal pump.

At this time, Specific Speed (Ns) is defined by the following equation.

……(식 1)

... ... (Equation 1)

Where Q = flow rate, Ht = heading, and N = number of revolutions.

Given the flow specifications Q, Ht, and the number of revolutions N of the design specifications of the centrifugal and extruder pump impellers 10, the specific velocity can be determined using Equation 1. [

At this time, the non-velocity is used as an index to distinguish the kind of the pump, and it is possible to distinguish the kind of the pump having the velocity. In an embodiment of the present invention, the smaller the specific speed, the more distinction is made between a centrifugal pump and a non-accelerated axial pump.

That is, the specific speed of the centrifugal pump is determined in the range of 150 to 600 Ns, the specific speed of the extruder pump is determined in the range of 400 to 1200 Ns, and the axial flow pump can be determined in the range of 1200 Ns or more.

However, the present invention is limited to a centrifugal pump and a hydrodynamic pump having a constant tendency of the design parameters of the impeller and the diffuser according to the specific speed, and the axial flow pump will be omitted.

At this time, the non-velocity is a dimensionless number, and the kind of the pump can be represented by the relational expression of the flow rate Q, the head Ht, and the number of rotations N. Thus, in one embodiment of the present invention, And may be a non-velocity of 150 to 1200 Ns.

In the embodiment of the present invention, the design parameters and the objective function determination step S10 are performed in order to generate the three-dimensional shape of the centrifugal and extruder pump impeller 10 and the diffuser 5 in consideration of the shape of the impeller and the diffuser. Determining the meridional surface design parameter of the impeller to be expressed, determining the meridional surface design parameter of the diffuser, determining the blade design variables expressing the impeller blade angle, and determining the blade angle design variable expressing the blade angle of the diffuser .

In the embodiment of the present invention, the determination of the meridional surface design parameter of the impeller may include the determination of the basic design parameters of the centrifugal and hydrodynamic pump impeller 10 and the determination of the meridian additional design parameters. At this time, the meridian plane is a part of the cross section of the impeller including the center line of the hub 11.

5 is a cross-sectional view illustrating a meridional plane of an impeller designed according to an optimum design method of an impeller and a diffuser according to an embodiment of the present invention. FIG. 6 is a schematic view illustrating design variables of blade angle of an impeller in an optimal design method of an impeller and a diffuser according to an embodiment of the present invention.

5 and 6, the basic design parameters for determining the basic design parameters of the impeller meridian are for capturing the morphology of the meridional surface. The radius R1_h of the hub at the inlet of the impeller, The inclination angle? 1 of the front end of the impeller blade, the radius R2 of the impeller exit portion, the blade width b2 at the trailing edge of the impeller blade, And an axial length Ztip of the shroud inlet and outlet ports.

At this time, the radius R1_h of the hub portion and the radius R1_s of the shroud portion among the variables indicate the area of the impeller inlet portion and the blade shape.

The tilted angle (1) of the impeller blade shear is related to the area of the inlet section, with respect to the radii (R1_h, R1_s), the area distribution of the blade front shear tilted with respect to the impeller center axis (Z axis).

The radius (R2) of the impeller outlet is a variable representing the overall size of the impeller, and the size of the impeller shape can be determined by the above parameters. The blade width b2 at the rear end of the impeller blade and the inclined angle 2 at the rear end of the blade determine the area of the outlet portion. The area thus determined affects the exit pressure and speed.

The axial length Ztip of the inlet and outlet of the shroud is a parameter for determining the size of the impeller shape in the axial direction by expressing the size in the axial direction of the impeller.

Referring to FIG. 5, additional design variables in the additional design parameter determination step are additional variables for connecting the hub portion and the shroud portion from the inlet portion to the outlet portion.

For this purpose, the additional design parameters of the meridian are: the inlet angle and the outlet angle (θ1_s, θ2_s), which the shroud curves of the impeller form with the horizontal and vertical lines, the inlet angle and the outlet angle (θ1_h, (% L_h,% L_s) of the straight portion of the impeller outlet hub hub and shroud; a shroud inlet adjustment point to create a Bezier curve from the point where the straight section of the outlet ends to the inlet of the impeller; and (% CP1_s,% CP2_s) and a hub entrance portion adjustment point and an exit portion adjustment point (% CP1_h,% CP2_h).

At this time, the length (% Lh,% Ls) of the straight portion in the impeller outlet hub and shroud represents the straight length section existing at the outlet portion.

The curved lines connecting the inlet and outlet of the impeller meridian face have a constant angle with respect to the horizontal line and the vertical line at the inlet and outlet. The curved line forms the inlet angle and the outlet angle (θ1_h, θ2_h, θ1_s, θ2_s) Represents the angle of the inlet and outlet sections on the sides of the hub and shroud, respectively.

In order to connect the outlet of the impeller at the end of the straight line section from the end of the straight section to the inlet section in the form of a smooth curve, a method of combining an arc may be used, or a Bezier curve may be used.

In this case, the Bezier curve is defined by defining the curve using the vertex of the polygon including the curve to be generated. The adjustment points (% CP1s,% CP2s,% CP1h,% CP2h) are adjustment variables for generating Bezier curves.

FIG. 6 is a schematic view showing blade design parameters in an optimum design method for a centrifugal and hydrostatic pump impeller according to an embodiment of the present invention.

Referring to FIG. 6, in the embodiment of the present invention, the blade angle design parameter determination step S12 is a curve for smoothly connecting the inlet / outlet angle of the impeller blade length to the bezier curve control method and the classical curve control method Can be defined.

In one embodiment of the present invention, it may be a Bezier curve control scheme. However, the blade angle design parameter determination step of the present invention is not limited to the Bezier curve control method, but may further include a classical curve control method.

In the embodiment of the present invention, the wing angle design variables for determining the wing angle design variables are for calculating the wing angle according to the Bezier curve method. The total length M_total_ (h, m, s) of the meridional curve, (h, m, s), the exit angle beta2_ (h, m, s), the length of the inlet straight line portion% beta_LE_ (h, m, s), the outlet angle beta_ (H, m, s) of the straight portion, an angle d_theta (m, h) inclined in the rotational direction at the exit portion, an adjustment point% CP_LE_ CP_TE_ (h, m, s). Here, the parameter h is the impeller hub, m is the impeller mid, and s is the impeller shroud.

On the other hand, the inlet angle beta1_ (h, m, s) related to the incident angle affects the flow rate and efficiency of the impeller and the outlet angle beta2_ (h, m, s)

FIG. 7 is a cross-sectional view illustrating a meridional plane of a diffuser in an optimum design method for an impeller and a diffuser according to an embodiment of the present invention. FIG. 8 is a schematic view showing design variables of a blade angle of a diffuser in an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.

Referring to FIG. 7, in the embodiment of the present invention, since the diffuser is connected to the rear end of the impeller, the design of the meridional surface of the diffuser may be correlated with the impeller meridian.

Also, to connect the diffuser inlet and outlet, a bezier curve can be used that can express a smooth curve in the same manner as the impeller meridian surface. At this time, the diffuser meridian is designed as an inflectional type, so diffuser meridian is connected using two Bezier curves in hub and shroud, unlike impeller meridian.

Referring to FIG. 7, the meridional surface design parameters of the diffuser in the meridional surface design parameter determination step of the diffuser include the radius (R3_h) of the hub portion at the diffuser inlet, the blade width (b3) at the front end of the diffuser wing, The radius R5_h of the hub portion at the diffuser outlet, the blade width b5 at the rear end of the diffuser wing, and the inclined angle 5 at the rear end of the diffuser wing, the radius R4h at the outermost point of the diffuser, The blade width b4 at the outermost point, and the tilted angle? 4 at the outermost point of the diffuser.

Also, referring to FIG. 7, when the adjustment point is determined on the Bezier curve of the diffuser meridian plane, the curve can be smoothly connected according to the entrance / exit angle. At this time, an angle (? 1_h) formed by the hub curve of the diffuser inlet with the horizontal line, an angle? 4_h formed by the hub curve of the diffuser outlet with the horizontal line, an diffuser inlet adjustment point (% CP1_s) on the shroud side, (% CP4_s), an angle (? 1_s) formed by the Shroud curve of the diffuser inlet with the horizontal line, and an angle (? 4_s) formed by the Shroud curve of the diffuser exit with the horizontal line

The hub side diffuser inlet adjustment point CP1_h, the hub side diffuser outlet adjustment point CP4_h, and the hub side first and second diffuser outermost point adjustment points CP2_h and CP3_h, (% CP2_s,% CP3_s) at the first and second diffuser side.

At this time, the axial length Z4 between the points at which the diffuser is bent at the inlet of the diffuser, and the axial length Z5 between the exit of the diffuser and the point at which it becomes inflexible.

The hub-side diffuser inlet adjustment point CP1_h may be the hub-side impeller outlet adjustment point CP1_h, and the angle? 1_h formed by the hub curve at the diffuser inlet with the horizontal line may be the same as the hub- Lt; RTI ID = 0.0 > (h1-h) < / RTI >

The diffuser inlet adjustment point CP1_s on the shroud side may be the impeller outlet adjustment point CP1_s on the shroud side and the angle θ1_s formed by the shroud curve on the impeller outlet with the horizontal line is the And an angle (? 1_s) between the wood curve and the horizontal line.

8, in the blade angle design variable determining step for expressing the blade angle of the diffuser, the blade development design parameter of the diffuser is determined by the exit start point TE start point, the sweep angle of the diffuser and the averaged radius r_theta_total (h, m, (h, m, s), the exit angle beta2_ (h, m, s), the entrance straight line length% beta_LE_ (h, m, s) of the entrance portion, CP_LE_ (h, m, s) of the entrance portion and the adjustment point% CP_TE_ (H, m, s), the exit angle beta2_ (h, m, s), the length of the inlet straight line portion% beta_LE_ (h, m, s), the length of the exit straight line portion% beta_TE_ m, s) and an angle d_theta (h, s) inclined in the rotation direction at the exit portion.

In the present invention, the diffuser blade development design variables are defined in accordance with the curve control method, namely, the Bezier curve control method and the classical curve control method. Here, the Bezier curve control method has an advantage that the blade length can be controlled because the sweep angle of the blade is included as a variable.

Here, referring to FIG. 7, the parameter h is a diffuser hub, m is a diffuser mid, and s is a diffuser shroud.

On the other hand, the inlet angle beta1_ (h, m, s) related to the incident angle affects the diffuser operating flow rate and the outlet angle beta2_ (h, m, s) affects the head and efficiency which are indicative of the diffuser performance.

In addition, the parameters of% beta_LE_ (h, m, s) and% beta_TE_ (h, m, s) of the exit straight line section of the inlet straight line section are the same Is not present because the angles of the inlet and outlet portions may have to be the same depending on the design of the diffuser.

The shape of the diffuser varies depending on the design of the non-velocity, and in particular, in the case of coupling with the diffuser in the centrifugal and extruder pumps, the shape of the diffuser (the outlet variable ), It is necessary to control the velocity distribution, since the velocity distribution varies and affects pump performance.

The variables of the adjustment point% CP_LE_ (h, m, s) of the inlet portion and the adjustment point% CP_TE_ (h, m, s) of the outlet portion are obtained by smoothly connecting the inlet / outlet angles of the diffuser Since the sweep angle of the diffuser is determined by the input / output angles, not by the fixed variables, when the diffuser sweep angles are given as design variables as described above, the input / output angles may not be smoothly connected, If an angle is specified, it indicates to adjust the Bezier curves to smoothly connect the inlet / outlet angles.

The classic curve control method defines the diffuser wing length as a curve that smoothly connects the inlet / outlet angle, so the diffuser inlet / outlet angle determines the blade length and sweep angle. Therefore, the blade development design parameter in the classic curved control system is defined by the product of the sweep angle of the diffuser and the averaged radius r_theta_total, the exit start point TE start point, the entry point% CP_LE_ (h, m, s) (H, m, s) variable CP_TE_ (h, m, s) is not required.

FIG. 9 is a schematic view showing major design parameters of impeller blades in an optimum design method of an impeller and a diffuser according to an embodiment of the present invention. 10 is a schematic view showing main design variables of the blade angle of the diffuser in the method of optimizing the design of the impeller and the diffuser according to the embodiment of the present invention.

9 and 10, in the main design parameter determination step (S20) of influencing the design objective value in one embodiment of the present invention, the main design parameters for improving the efficiency and satisfying the accurate heading are the variables , The impeller exit angle (beta2_ (h, s)) and the diffuser inlet angle (beta1_ (h, s)) are determined as the main design parameters of the impeller and diffuser.

That is, the exit angle of the impeller hub (i_beta2_h), the exit angle of the impeller shroud ((_beta2_s), the entrance angle of the diffuser hub (d_beta1_h), and the entrance angle of the diffuser shroud (d_beta1_s) .

Meanwhile, in the step S30 of grasping the condition of the optimum design factor for optimizing the value of the objective function in the embodiment of the present invention, the optimal design range of the main factors can be obtained by using the 2 ^k factor test method.

In this case, the 2 ^k factor method is a method of determining the significance of each factor by performing experiment on the level of each factor for ^k factors. At this time, to obtain all the effects of the three factors, the size of the experiment should be 2 ³ = 8, and the interaction between the main effects of the factors should be sought.

However, in the case of interactions, there are many cases that can be ignored, and in some cases this is the case. Some implementations can reduce the number of experiments compared to the factorial method with the same number of factors by testing and eliminating negligible effects.

In one embodiment of the present invention, fractional factorial designs (hereinafter, referred to as " fractional factorial designs ") are used in which the number of experiments is reduced by interfering with meaningful high-order interactions taking into account the number of factors of interest, ) Were used for the 2 ^k factor test.

At this time, the experimental design method is based on the modern statistical analysis method, and it is a method to quantitatively determine the important cause among the many causes causing the abnormal fluctuation at a low cost. At the same time, you can measure their effects separately for two or more factors.

In the embodiment of the present invention, the optimum design parameters for the optimum design using the experimental design method are that the exit angle (i_beta2_h) of the impeller hub is 27 to 35 degrees and the exit angle (i_beta2_s) of the impeller shroud is 12 The inlet angle (d_beta1_h) of the diffuser hub may be between 139 degrees and 147 degrees, and the inlet angle (d_beta1_s) of the diffuser shroud may be between 146 degrees and 154 degrees.

In this case, the variables other than the four major factors are selected as the reference model with good performance out of the result values obtained through the 2 ^k factorial designs and the response surface method, The 2 ^k factor method was used for the inlet angle (d_beta1_h) of the diffuser hub and the inlet angle (d_beta1_s) of the diffuser shroud at the exit angle (i_beta2_h) of the impeller hub and the exit angle (i_beta2_s) of the impeller shroud.

Meanwhile, in the step S40 of deriving the optimized shape of the impeller and the diffuser by using the reaction surface technique under the optimum design parameter condition in the embodiment of the present invention, the centrifugal and multiphase pump impellers and the diffuser, The response surface method was used to determine the shape that satisfies both target values and the target of design.

In this case, the Response Surface Method (RSM) is a method of statistically analyzing the problem that multiple reactions occur due to multiple variable actions. This is a statistical method of analyzing the response surface of changes in these responses when giving.

In addition, the response surface technique can estimate not only which factors are affected, but also which combinations are most effective.

If we estimate the presence or absence of an effect through a combination of factors in a general experimental design, the response surface method can estimate the equation when the factors affect and the factors show the greatest effect.

The reaction surface technique applied in the present invention performs optimization by the experiment of 4 factor 5 level. (D_beta1_h) of the diffuser hub and the inlet angle (d_beta1_s) of the diffuser shroud are selected as the design variables and the objective function (i_beta2_h) of the impeller hub and the impeller shroud And the reaction surface method is performed.

(I_beta2_h) of the impeller hub and the inlet angle (d_beta1_h) of the diffuser hub (i_beta2_s) of the impeller shroud in the embodiment of the present invention have four main factors that greatly affect the head and the efficiency of the impeller and the diffuser. And the entrance angle (d_beta1_s) of the diffuser shroud, and the numerical simulation conditions were generated using the central composite of the response surface method with these four parameters.

11 is a graph illustrating a reaction optimization method in an optimum design method of a centrifugal impeller and a hydrodynamic pump impeller according to an embodiment of the present invention.

11, the impeller hub exit angle (i_beta2_h) is 28 degrees, the impeller shroud exit angle (i_beta2_s) is 20.0 degrees, the diffuser hub inlet angle (d_beta1_h) is 139.0 degrees, When the wood inlet angle (d_beta1_s) is 146.0 degrees, the efficiency can be 90.6669 and the head can be 13.8192. At this time, the target value of the head is 13.80. It can be seen that the reliability (d) of the efficiency of this optimized value is 0.66673 and the reliability (d) of the lift is 0.98078.

At this time, the design variables and the objective function values of the impeller and the diffuser are dimensionless based on the reference model.

That is, the impeller hub outlet angle (i_beta2_h) The main design parameters, the impeller shroud outlet angle (i_beta2_s), except for the diffuser hub entrance angle (d_beta1_h) and the diffuser shroud inlet angle (d_beta1_s) remaining design variables are 2 ^k factors Experimental Method ( factorial designs, and response surface method, the value of the performance can be selected and fixed as a reference model.

At this time, the reference model impeller and diffuser of the desired performance can be selected as optimal values from the results obtained through the 2 ^k factorial designs and the response surface method.

12 is a perspective view illustrating numerical analysis boundary conditions and a lattice system of an impeller and a diffuser designed by an optimum design method of an impeller and a diffuser according to an embodiment of the present invention.

In the numerical analysis, the design target values of the centrifugal and multistage pump impellers are obtained by the shear stress transport (SST) turbulence model analysis based on K-ω using the commercial code ANSYS CFX-16.0 of the finite volume corporation ANSYS Can be.

At this time, ANSYS Blade-Gen and Turbo-Grid can be used for blade shape definition and grid generation, respectively.

Referring to FIG. 10, a 3D geometry of the impeller was generated using the ANSYS CFX-BladeGen program, and a structured grid was created using the ANSYS CFX TurboGrid, a fluid mechanical grid generation program, for the generated blade shape.

The number of blades of the impeller is 5 and the number of blades of the diffuser is 7. However, since the impeller and diffuser used for the numerical analysis have the same blade shape, the period of the impeller and the diffuser Numerical analysis was performed only for the wing area.

Referring to FIG. 12, the number of generated grid systems is 930,000. Numerical analysis was performed using ANSYS CFX-16.0, a commercial three-dimensional viscous fluid analysis program. A 3-D Reynolds mean Navier-Stokes equation was used to analyze the incompressible turbulent flow inside the impeller and diffuser.

The governing equations used in the numerical analysis are discretized by the finite volume method and the high resolution scheme with the second order or higher accuracy is used as the discretization method.

The shear stress transport k-ω model, which is suitable for predicting the flow separation, was used as the turbulence model used for the analysis of the turbulent flow.

At the boundary condition, the atmospheric pressure was uniformly applied to the inlet of the impeller and the outlet of the diffuser, and the mass flow rate was applied to the outlet, and the impeller rotation speed was 2400 rpm. At this time, water was used as the working fluid.

The impeller and the diffuser designed according to the embodiment of the present invention, the impeller and the diffuser and the centrifugal and extruder pumps having the impeller and the diffuser designed by this method can design the impeller outlet portion and the diffuser inlet portion at the same time, .

The optimal design method of the impeller and the diffuser according to the embodiment of the present invention can shorten the time for designing the shape of the impeller and the diffuser by using the design of the experiment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: Centrifugal and extruder pump 2: Casing
3: inlet 5: diffuser
6: diffuser wing 7: diffuser hub
9: diffuser shroud 10: impeller
11: impeller hub 13: impeller blade
15: impeller shroud 30: drive shaft of the motor

Claims (17)

1. A method for optimizing an impeller and a diffuser for optimizing a diffuser and a diffuser connected to the impeller and for discharging a fluid introduced through the impeller to the outside,
Determining a design parameter and an objective function in consideration of shapes of the impeller and the diffuser;
Determining a main design variable that affects a value of the objective function;
An optimal design parameter condition grasp step of optimizing the value of the objective function and
And deriving an optimized shape of the impeller and the diffuser by using a reaction surface technique at the optimal design parameter condition,
The specific speed is determined by the flow quantity Q, the head Ht and the number of rotations N, which are design specifications, in the design parameters and the objective function determining step in consideration of the shape of the impeller and the diffuser, Ns,
In the design parameter and objective function determining step, considering the shape of the impeller and the diffuser, the objective function is a head Ht and efficiency (t) for analyzing the performance of the impeller and the diffuser,
The step of determining the design parameters of the impeller and the diffuser
An impeller meridian surface design parameter determination step of expressing a shape of a blade of the impeller to generate a three-dimensional shape of the impeller;
A diffuser meridional surface design parameter determination step of expressing a shape of a blade of the diffuser to generate a three-dimensional shape of the diffuser;
Determining an impeller blade angle design variable expressing a blade angle of the impeller;
And determining the diffuser wing angle design variable representing the wing angle of the diffuser,
In the determination of the meridional surface design parameters of the diffuser, the meridional surface design parameters of the diffuser include a radius (R3_h) of the hub portion at the diffuser inlet, a blade width (b3) at the front end of the diffuser blade, a tilted angle The radius at the outermost point of the diffuser (R4h), the blade width (b4) at the diffuser outermost point, the tilted angle (? 4) at the diffuser outermost point, the radius at the diffuser exit (R5h) The inclination angle? 5 at the diffuser outlet, the hub side diffuser inlet adjustment point CP1h and the first and second diffuser outermost point adjustment points CP2h and CP3h at the hub side, ), The hub side diffuser outlet adjustment point (% CP4h), the angle (? 1h) formed by the hub curve of the diffuser inlet with the horizontal line, the angle? 4h formed by the hub curve of the diffuser outlet with the horizontal line, (% CP1s), the first and second diffuser outline on the shroud side (% CP2s,% CP3s), the diffuser outlet adjustment point (% CP4s) at the shroud side, the angle (? 1s) at which the Shroud curve at the diffuser inlet intersects the horizontal line, and the Shroud curve at the diffuser exit Optimum design method of impeller and diffuser including angle? 4s. delete delete delete The method according to claim 1,
In the designing of the impeller meridian surface design parameter, the meridional surface design parameter of the impeller is determined by a radius R1_h of the hub portion at the inlet portion of the impeller, a radius R1_s of the shroud portion at the inlet portion of the impeller, A diameter of the outlet of the impeller R2, a width of a blade at a trailing edge of the impeller blade, an angle of inclination of a forward end of the blade and an angle of a shroud inlet and an outlet, Optimized design method of impeller and diffuser including direction length (Ztip). 6. The method of claim 5,
The meridional surface design parameters of the impeller include an inlet angle and an outlet angle (? 1_s,? 2_s) formed by the shroud curves of the impeller with a horizontal line and a vertical line, an inlet angle and an outlet angle , θ2_h) Length (% L_h,% L_s) of the straight portion in the impeller outlet hub and shroud, shroud inlet portion adjustment to create a Bezier curve from the end of the straight section of the outlet to the impeller inlet (CP1_s,% CP2_s), and a hub inlet adjustment point and an outlet adjustment point (% CP1_h,% CP2_h) for optimizing design of an impeller and a diffuser. The method according to claim 6,
The blade angle design parameter determination step of the impeller
(H, m, s), exit point TE start point, the product of the sweep angle of the impeller and the averaged radius r_theta_total_ (h, m, s), the entrance angle beta1_ (H, m, s), the length of the inlet straight section% beta_LE_ (h, m, s), the length of the exit straight section% beta_TE_ (h, m, s), and the angle d_theta (h, m, s) of the inlet portion and an adjustment point% CP_TE_ (h, m, s) of the outlet portion. delete 8. The method of claim 7,
In the wing angle design variable determining step of the diffuser, the vane development design parameter includes an exit start point (TE start point), a product of the sweep angle of the diffuser and the averaged radius (r_theta_total), the entrance angle (beta1_ (h, m, s) (H, m, s)), the length of the exit rectilinear section (% beta_TE_ (h, m, s) (H, m, s) including an adjustment point (CP_LE_ (h, m, s)) of the inlet portion, an inclination angle (d_theta And optimizing design method of diffuser. 10. The method of claim 9,
In the main design parameter determination step, which affects the design parameter value, the main design parameter includes an exit angle (i_beta2_h) of the impeller hub, an exit angle (i_beta2_s) of the impeller shroud, Wherein the inlet angle (d_beta1_h) of the hub and the inlet angle (d_beta1_s) of the diffuser shroud are optimized. 11. The method of claim 10,
The remaining design variables, except for the main design variables, are optimized to optimal values from 2 ^k factorial designs and results from the response surface method. 11. The method of claim 10,
In the step of grasping the condition of the optimal design variable capable of optimizing the objective function value, the specific speed is the same, the starting point S1_h of the inlet hub is fixed to the same axis C2 in the radial direction, The inner diameter R1_h of the hub portion at the inlet portion is the same and the inner diameter R1_s of the shroud portion at the inlet portion is equal to the inner diameter R1_s of the impeller blade portion at the inlet portion, And an inlet angle (? 1_s) to the vertical line are fixed equally. 13. The method of claim 12,
The exit angle (i_beta2_h) of the impeller hub is in a range of 27 to 35 degrees and the exit angle (i_beta2_s) of the impeller shroud is in a range of 12 to 20 degrees in an optimum design parameter condition grasping step in which the objective function value can be optimized , The inlet angle (d_beta1_h) of the diffuser hub is between 139 degrees and 147 degrees, and the inlet angle (d_beta1_s) of the diffuser shroud is between 146 degrees and 154 degrees. 14. The method of claim 13,
(I_beta2_h), the impeller hub exit angle (i_beta2_h) at which the head and the efficiency simultaneously satisfy the optimized shape of the impeller and the diffuser at the derivation step using the reaction surface method, (D_beta1_h) and the inlet angle of the diffuser shroud (d_beta1_s) are derived. An impeller and diffuser designed by an optimized design method of an impeller and a diffuser according to any one of claims 1, 5 to 7, 9 to 14. An impeller and a diffuser according to claim 15;
And a casing having the impeller installed therein and having an inlet formed to suck the fluid in front of the impeller and a discharge port configured to discharge the sucked fluid to the outer periphery of the impeller. An impeller and a diffuser according to claim 15;
And a casing having the impeller installed therein and having an inlet formed to suck the fluid in front of the impeller and a discharge port configured to discharge the sucked fluid to the outer periphery of the impeller.

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