KR102662661B1 - The design method of the blade angle distribution for the low specific speed centrifugal pump impeller that satisfies the design specifications and performance, impeller and pump by the method - Google Patents

Abstract

The present invention relates to a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance, and an impeller and pump designed thereby.
A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance according to an embodiment of the present invention includes the steps of determining design specifications of the impeller; determining a specific speed of the impeller; determining design variables of the impeller; Deriving the optimal shape of the impeller; And it may include comparing the optimal shape of the impeller with a preset reference impeller to function the tendency of the design variable of the impeller according to the specific speed.

Description

The design method of the blade angle distribution for the low specific speed centrifugal pump impeller that satisfies the design specifications and performance, impeller and pump by the method}

The present invention relates to a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance, and an impeller and pump designed thereby.

Pumps can be used for fluid transfer in general homes and industries, and in various plant industries (chemical, nuclear power, power plants, marine plants, etc.). Depending on the operation method, pumps can be classified into positive displacement type, which is reciprocating and rotary, and turbo type, which is centrifugal. Here, the shape of the turbo-type pump can be classified according to the required specifications.

If the pump specifications require low flow and high pressure, it can be designed as a centrifugal pump, and if high flow and low pressure are required, it can be designed as an axial flow pump. In addition, the pump shape has a specific speed defined by the flow rate, head, and rotation speed of the design specifications, and can be classified into centrifugal, four-flow, and centrifugal types depending on the specific speed and pump operation characteristics.

Here, a centrifugal pump is a device that pumps water using centrifugal force transmitted to the water by an impeller rotating at high speed. Water enters the center of the impeller and exits toward the periphery. It is a pump for low-flow, high-pressure water supply and has a lower specific speed than axial-flow or diagonal-flow pumps, and the discharged water flows vertically by the impeller.

Such a conventional centrifugal pump includes Republic of Korea Patent No. 10-0469567, 'Low-noise impeller design method using reverse engineering technique'.

In the past, in order to derive a pump impeller shape that satisfies the performance within the required design specifications, there was a problem in that the optimal design of the pump impeller had to be performed for each required design specification.

Developed based on the above technical background, one embodiment of the present invention is a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance that can optimize the performance of the pump impeller for each design specification. , we aim to provide impellers and pumps designed accordingly.

In order to achieve the above object, the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention is an impeller design method for a low specific speed centrifugal pump, the impeller of the impeller determining design specifications; determining a specific speed of the impeller; determining design variables of the impeller; Deriving the optimal shape of the impeller; And it may include the step of functionalizing the tendency of the design variable of the impeller according to the specific speed.

Additionally, in the step of determining the design specifications of the impeller, the design specifications may be flow rate, head, and rotation speed.

In addition, in the step of determining the specific speed of the impeller, the specific speed is

, where Ns is the specific speed, Q is the flow rate, H is the head, and n is the rotation speed, and the specific speed can be determined by the flow rate, head, and rotation speed.

Additionally, the specific speed may be determined in the range of 50 to 150.

Additionally, the impeller may have five blades.

Additionally, the efficiency of the impeller may have a tendency for each unit section depending on the specific speed value in the range of 50 to 150 specific speeds.

In addition, determining the design variable of the impeller includes determining a design variable of a meridional plane representing the blade shape of the impeller; And it may include determining a design variable of the blade angle representing the blade angle of the impeller.

In addition, in the step of determining the design variable of the meridional plane, the design variable of the meridional plane is the radius of the hub portion at the inlet of the impeller, the radius of the shroud portion at the inlet of the impeller, and the inclination of the blade front end of the impeller. It may include the angle, the radius of the outlet portion of the impeller, the blade width at the rear end of the impeller blade, the inclined angle of the rear end of the blade, and the axial length of the shroud inlet and outlet portions.

In addition, the meridional design variables are the inlet angle and outlet angle formed by the shroud curve of the impeller with the horizontal and vertical lines, the inlet angle and outlet angle formed by the hub curve of the impeller with the horizontal and vertical lines, and the outlet angle of the impeller. The length of the straight portion of the hub and shroud, the shroud inlet adjustment point and outlet adjustment point, and the hub inlet adjustment point to create a Bezier curve from the end of the straight section of the outlet to the inlet of the impeller, and An outlet adjustment point may be included.

In addition, in the step of determining the design variable of the blade angle, the design variable of the blade angle is the total length of the meridional curve, the product of the sweep angle of the impeller and the average radius, the inlet angle, the outlet angle, the length of the inlet straight portion, and the outlet straight portion. It may include length and angle inclined toward the direction of rotation at the outlet.

Additionally, the outlet angle includes an outlet angle at the hub and an outlet angle at the shroud, the inlet angle includes an inlet angle at the hub and an inlet angle at the shroud, and the inlet angle at the hub is an outlet angle at the hub. The angle of incidence and the flow angle at the hub may be included, and the entrance angle at the shroud may include the angle of incidence at the shroud and the angle of flow at the shroud.

Additionally, the angle of incidence at the hub may have a tendency for each unit section depending on the specific speed value in the range of 50 to 150.

Additionally, the angle of incidence at the hub is

^Y ₁ = _{- A 1}

_, where Y _{1 is the} angle of incidence at the hub, It may be a constant determined in the range of 1.1.

Additionally, the flow angle at the hub is

^Y ₂ = _{- A 2}

_, where Y _{2 is the} flow angle at the hub, It may be a constant determined in the range of ~ 0.8.

Additionally, the angle of incidence at the shroud is

Y _{3 = -} ^A ₃

, where Y _{3 is the angle} of incidence at the shroud, It may be a constant determined in the range of ~ 1.03.

Additionally, the flow angle at the shroud is

^Y ₄ = _{- A 4}

_, where Y _{4 is} the flow angle at the _shroud , It may be a constant determined in the range of 0.9 to 1.

Additionally, the exit angle from the hub is

^Y ₅ = _{- A 5}

_, where Y _{5 is} the exit _angle from the hub, It may be a constant determined in the range of ~ 0.11.

Additionally, the exit angle from the shroud is

Y _{6 = -} ^A ₆

_, where Y _{6 is} the exit _angle from the shroud, It may be a constant determined in the range of 0.1 to 0.11.

In addition, deriving the optimal shape of the impeller includes determining key design variables that affect the design target value, which is the efficiency of the impeller; And it may include the step of identifying the conditions of optimal design variables that can optimize the design objective value by using a response surface technique.

In addition, in the step of determining key design variables, the key design variables include an outlet angle at the hub, an outlet angle at the shroud, an inlet angle at the shroud, an inlet angle at the hub, and an outlet angle at the shroud. It may be the angle of incidence, the angle of flow at the shroud, the angle of incidence at the hub, and the angle of flow at the hub.

In addition, other than the main design variables, the remaining design variables can be fixed to optimized values among the results obtained through the ^2k factorial experiment method and the response surface method.

In order to achieve the above object, the impeller according to an embodiment of the present invention can be designed by a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance.

In order to achieve the above object, a pump according to an embodiment of the present invention includes an impeller according to claim 22; The impeller is installed inside, and may include a casing having an intake port formed to suck fluid into the front of the impeller and an outlet formed to discharge the sucked fluid to the outer periphery of the impeller.

The low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention can design an impeller shape that can optimize the performance of the impeller for each design specification.

The low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention can design a pump impeller that satisfies efficiency for each specific speed using design variable tendencies.

Figure 1 shows a classification diagram of the pump.
Figure 2 is a cross-sectional view of the meridional plane of a centrifugal pump with an impeller designed by a low-specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 3 shows a flowchart of a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 4 shows the process of deriving an impeller through a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 5 shows a front view of an impeller designed by a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 6 is a schematic diagram showing meridional design variables in a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance according to an embodiment of the present invention.
Figure 7 is a schematic diagram showing blade angle design variables in a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance according to an embodiment of the present invention.
Figure 8 is a schematic diagram showing the inlet angle in the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 9 shows an impeller according to specific speed designed through a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 10 is a graph showing the angle of incidence at the hub according to the specific speed of the impeller designed by the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 11 is a graph showing the efficiency according to the specific speed of the impeller designed by the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 12 is a case diagram showing the process of deriving the three-dimensional shape of the impeller using the tendency of the design variables of the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention. am.
Figure 13 shows the impeller design variable determination step of the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 14 shows the step of deriving the optimized shape of the impeller using the design of experiment method of the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention.
Figure 15 shows the numerical analysis boundary conditions and grid system of the impeller to verify the performance of the impeller designed by the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention. It is a perspective view.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and identical or similar components are given the same reference numerals throughout the specification.

In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Referring to Figure 1, there are various pumps depending on the required specifications, but in the case of the present invention, a turbo pump will be described among them. Turbo pumps can be classified into centrifugal (Ns 50 ~ 600), diagonal flow (Ns 400 ~ 1400), and axial flow (Ns 1200 or more) depending on the specific speed.

The present invention relates to a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance, and an impeller and pump designed thereby. The present invention is limited to centrifugal pumps that have a certain tendency between specific speed and impeller design variables, and oblique flow pumps and axial flow pumps will be omitted.

Referring to FIG. 2, the pump 1 according to an embodiment of the present invention may include an impeller 10 and a casing 2 designed by an impeller design method.

At this time, an impeller 10 that rotates at high speed between the suction port 3 and the discharge port 5 and sucks in and discharges fluid is coupled to the inside of the centrifugal pump.

Meanwhile, the impeller 10 of a centrifugal pump is installed adjacent to the casing 2, and an inlet 3 through which fluid is sucked is formed at the front center of the impeller 10, and a suction port 3 is formed on the outer periphery of the impeller 10. The discharge port 5 may be formed so that the liquid is discharged in the radial direction.

Referring to FIG. 5, the impeller 10 according to an embodiment of the present invention may include a hub 11, a shroud 15, and wings 13.

At this time, the hub 11 is a part that is coupled to the drive shaft 30 of the motor and receives the rotational force of the motor rotating around the drive shaft, and may be made of a material with high rigidity suitable for high-speed rotation.

Additionally, the hub 11 may be formed to have a cone shape whose cross-sectional area decreases as it moves in the direction of the drive shaft 30. That is, a hub 11 is formed in the center of the impeller 10, and a drive shaft 30 is coupled to the hub so that the rotational force of the motor can be transmitted to the impeller 10.

A plurality of wings 13 may be formed radially on the circumferential surface centered on the hub 11. At this time, the plurality of wings 13 may be composed of five, but is not limited to this.

Meanwhile, the shroud 15 may be formed to connect the outer ends of the plurality of wings 13 disposed on the hub 11 and surround the entire outer ends. This shroud 15 can connect each of the plurality of wings 13.

In order to analyze the tendency of centrifugal pump impeller shape according to specific speed, the present invention established the design variables of the centrifugal pump impeller and analyzed the tendency of the design variable according to specific speed using the established design variables.

In addition, by analyzing the optimally designed centrifugal pump pump shape and advanced literature through previous research, trends in design variables according to specific speed were identified. In addition, the centrifugal pump impeller shape was designed using the centrifugal pump shape and the trends of design variables established based on advanced literature. In addition, the performance of the centrifugal pump impeller shape designed using the trends of design variables was verified using numerical analysis.

Referring to FIG. 3, the impeller design method according to an embodiment of the present invention includes a design specification determination step of the impeller (S10), an impeller specific speed determination step (S20), an impeller design variable determination step (S30), and an impeller design step (S10). It may include a step of deriving an optimized shape (S40) and a step of functionalizing the tendency of the design variable according to the specific speed (S50).

The low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention changes the meridional shape and blade angle of the impeller depending on the specific speed. At this time, the meridional shape and blade angle change By identifying trends, the impeller efficiency of the pump can be optimized.

Referring to FIG. 3, the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention may include a step (S10) of determining the design specifications of the impeller. Meanwhile, in the impeller design specification determination step (S10), the flow rate (Q), head (H), and rotation speed (n), which are the design specifications required when designing the impeller (10) of the pump (1), are determined, and the pump This may be a required specification when designing the impeller 10 of (1).

At this time, the flow rate (Q) and head (H) are specifications that must be basically satisfied while the impeller 10 of the centrifugal pump 1 rotates, and the rotation speed (n) can be determined according to the specifications of the motor.

Meanwhile, the impeller 10 of the pump 1 may be designed to have the highest efficiency at a given flow rate and head. The wing shape and meridional shape may change depending on the rain speed.

In the specific speed determining step (S20), the type of pump 1 can be determined by determining the specific speed, and in one embodiment of the present invention, the type of pump may be a centrifugal pump.

At this time, specific speed (Ns) is defined as the following equation.

At this time, Ns is the specific speed, Q is the flow rate (unit: m ³ /min), H is the head (unit: m), and n is the number of rotations (unit: rpm).

Specific speed can be determined by flow rate, head, and rotation speed, and can be provided as a dimensionless number. In other words, given the pump impeller design specifications of flow rate (Q), head (H), and rotation speed (N), the specific speed can be obtained using Equation 1.

In the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention, the specific speed can be determined in the range of 50 to 150. In addition, the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention can design the impeller of the centrifugal pump.

Referring to FIG. 13, in one embodiment of the present invention, the impeller design variable determination step (S30) includes the design variable determination step (S31) of the meridional plane representing the blade shape and the blade angle to generate the three-dimensional shape of the impeller of the pump. It may include a design variable determination step (S32) of the blade angle expressing . At this time, the meridional plane is a part of the cross section of the impeller including the center line of the hub.

In addition, the design variables of the centrifugal pump impeller can be established as the design variables of the meridional plane and the design variables of the blade angle, respectively.

In the design variable determination step of the meridional plane (S31), the design variables of the meridional plane are used to set the basic frame of the meridional plane, including the radius of the hub portion at the inlet of the impeller (R1_h) and the radius of the shroud portion at the inlet of the impeller (R1_s). , the inclined angle of the leading edge of the impeller blade (ϕ1), the radius of the impeller exit portion (R2), the blade width at the trailing edge of the impeller blade (b2), the inclined angle of the trailing edge of the impeller blade (ϕ2), and the shroud inlet portion. and the axial length (Ztip) of the outlet portion.

At this time, among the basic design variables, the radius of the hub portion (R1_h) and the radius of the shroud portion (R1_s) represent the area and blade shape of the impeller inlet portion.

In addition, the inclined angle (ϕ1) of the impeller blade leading edge represents the angle at which the area distribution of the blade leading edge is inclined relative to the impeller central axis (Z axis) in relation to the radius (R1_h, R1_s), and is related to the area of the inlet part. do.

In addition, the radius (R2) of the impeller outlet is a variable that expresses the overall size of the impeller, and the size of the impeller shape can be determined by the above variable. The blade width (b2) at the rear end of the impeller blade and the inclined angle (ϕ2) at the rear end of the blade determine the area of the outlet portion. The area thus determined later influences the outlet pressure and velocity.

In addition, the axial length (Ztip) of the shroud inlet and outlet is a variable used to determine the size of the impeller shape in the axial direction by expressing the axial size of the impeller.

Referring to FIG. 6, in the step of determining additional design variables of the impeller meridional surface, the additional design variables are additional variables for connecting the hub portion and shroud portion from the inlet portion to the outlet portion.

For this purpose, the additional meridional design variables are the inlet and outlet angles (θ1_s, θ2_s) formed by the shroud curve of the impeller with the horizontal and vertical lines, and the inlet and outlet angles (θ1_h, θ2_h), the length of the straight section in the hub and shroud of the impeller outlet (%L_h, %L_s), the shroud inlet adjustment point to create a Bezier curve from the end of the straight section of the outlet to the impeller inlet, and It may further include outlet adjustment points (%CP1_s, %CP2_s), and hub inlet adjustment points and outlet adjustment points (%CP1_h, %CP2_h).

At this time, the lengths (%L_h, %L_s) of the straight portions at the hub and shroud of the impeller outlet represent the straight length section existing at the outlet.

In addition, the curve connected at the inlet and outlet of the impeller meridional plane forms a curve at a certain angle with respect to the horizontal and vertical lines at the inlet and outlet, and the inlet and outlet angles (θ1_h, θ2_h, θ1_s, θ2_s) ) represents the angle of the inlet and outlet portions on each side of the hub and shroud.

Meanwhile, a method of combining arcs can be used to connect the end of the straight section of the outlet part of the impeller to the inlet part in a smooth curved form, or a Bezier curve can be used. At this time, the Bezier curve is expressed by defining a curve using the vertices of a polygon that approximates the curve to be created. At this time, the adjustment points (%CP1_s, %CP2_s, %CP1_h, %CP2_h) are adjustment variables for creating a Bezier curve.

The blade angle design stage is a curve that smoothly connects the inlet/outlet angles of the impeller blades, and can be defined in two ways: Bezier curve control method and classical curve control method.

In one embodiment of the present invention, the Bezier curve control method will be described later. However, the blade angle design step of the present invention is not limited to the Bezier curve control method and may further include a classical curve control method.

Referring to Figures 7 and 8, in the blade angle design variable determination step (S32), the blade angle design variable is the total length of the meridional curve (M_total_(h,m,s)), the product of the sweep angle of the impeller and the averaged radius ( r_theta_total), inlet angle (beta1_(h,m,s)), outlet angle (beta2_(h,m,s)), length of inlet straight part (%beta_LE_(h,m,s)), length of outlet straight part ( %beta_TE_(h,m,s)), includes the angle (d_theta(m,h)) tilted in the direction of rotation at the outlet. At this time, the parameter h is the impeller hub, m is the impeller mid, and s is the impeller shroud.

Meanwhile, the inlet angle beta1_(h,m,s), which is related to the angle of incidence, affects the impeller operating flow rate, and the outlet angle beta2_(h,m,s) has a significant impact on the head and efficiency of the impeller performance.

And, the exit angle (beta2_(h,m,s)) includes the exit angle at the hub (beta2_(h)) and the exit angle at the shroud (beta2_(s)).

Referring to Figure 8, the entrance angle (beta1_(h,m,s)) includes the entrance angle at the hub (beta1_h) and the entrance angle at the shroud (beta1_s), and the entrance angle at the hub (beta1_h) is Contains the angle of incidence at the hub (i_beta_h) and the angle of flow at the hub (i_flow_h), and the angle of entry at the shroud (beta1_s) includes the angle of incidence at the shroud (i_beta_s) and the angle of flow at the shroud (i_flow_s). do.

The entrance angle at the hub (beta1_h) is the sum of the incident angle at the hub (i_beta_h) and the flow angle at the hub (i_flow_h).

The entrance angle at the shroud (beta1_s) is the sum of the incident angle at the shroud (i_beta_s) and the flow angle at the shroud (i_flow_s).

And, the flow angle is the angle at which fluid enters the inlet part of the hub and shroud.

Referring to FIG. 14, in one embodiment of the present invention, the step of deriving the optimized shape of the impeller using the design of experiment method (S40), the step of determining the main design variables affecting the design objective value (S41), and the step of determining the design objective by the response surface technique. It may include a step of identifying the conditions of optimal design factors that can optimize the values (S42) and a step of deriving the optimized shape of the impeller using a response optimization technique with optimal design variable conditions (S43).

At this time, the experimental design method is a method of selecting important causes among many causes of abnormal fluctuations at low cost and measuring the effects quantitatively based on modern statistical analysis methods. And, by targeting two or more types of factors at the same time, their effects can be measured individually.

In one embodiment of the present invention, the response surface method (RSM) of the design of experiment method was used as a numerical optimization technique for optimal design.

In order to analyze the performance of an impeller according to design variables, the design objective value must be defined. At this time, the design objective value may be the efficiency of the impeller, which indicates the performance of the impeller.

Referring to Figure 16, the 3D shape of the impeller was created using the ANSYS CFX-BladeGen program, and a structured grid was created for the generated blade shape using ANSYS CFXTurboGrid, a fluid machine grid generation program.

The number of impeller blades is 5, but since the blade shape of the impeller used in the numerical analysis is the same, the numerical analysis was performed only for the blade area of one impeller using periodic conditions in consideration of analysis time.

The 2 ^k factorial experiment method is a method of determining the significance of each factor by conducting an experiment on the level of each factor for k factors. For example, to find all the effects of three factors, the size of the experiment should be 8 and the main effects and interactions of the factors should be found.

In the main design variable determination step (S41), the main design variables are the outlet angle from the hub (beta2_(h)), the outlet angle from the shroud (beta2_(s)), the inlet angle from the shroud (beta1_s), and the hub. It may be the entrance angle (beta1_h), the incidence angle at the shroud (i_beta_s), the flow angle at the shroud (i_flow_s), the incidence angle at the hub (i_beta_h), and the flow angle at the hub (i_flow_h).

Here, the entrance angle at the shroud (beta1_s) can be derived as the sum of the incident angle at the shroud (i_beta_s) and the flow angle at the shroud (i_flow_s), and the entrance angle at the hub (beta1_h) is the angle at the hub. Since it can be derived from the sum of the incident angle (i_beta_h) and the flow angle at the hub (i_flow_h), it can be excluded.

In addition, the remaining design variables, excluding the main design variables, can be fixed to optimized values among the results obtained through the ^2k factorial experiment method and response surface technique.

Additionally, the length of the inlet straight part (%beta_LE_(h,m,s)) and the length of the outlet straight part (%beta_TE_(h,m,s)) are the total length of the meridional curve (M_total_(h,m,s)). It can be fixed at 10% to 30% of .

In the step (S42) of identifying the conditions of optimal design factors that can optimize the design objective value using the response surface technique, the response surface technique is a method of statistically analyzing problems in which responses appear complex due to the action of multiple variables, It is a statistical analysis method for the response surface formed by changes in response when several design variables influence an objective function through complex actions.

In addition, the response surface technique can estimate not only what factors have influence, but also what combination of factors can have the greatest effect.

In a general experiment plan, if you estimate the presence or absence of an effect through a combination of factors, the response surface technique can estimate which factors have an effect and the equation when those factors show the greatest effect.

In one embodiment of the present invention, in the step (S43) of deriving the optimized shape of the impeller using a reaction optimization technique with optimized design variable conditions, the impeller of the centrifugal pump with optimal impeller efficiency is set to the target of design. was set, and a response optimization technique was used to determine a shape that satisfies the target value.

Through this, the main design variables: exit angle at the hub (beta2_(h)), exit angle at the shroud (beta2_(s)), incident angle at the shroud (i_beta_s), flow angle at the shroud (i_flow_s), The shape of the impeller of a centrifugal pump with optimized incident angle at the hub (i_beta_h) and flow angle at the hub (i_flow_h) can be derived.

In addition, the design variables in the shape of the impeller of the centrifugal pump optimized for each specific speed are the outlet angle at the hub (beta2_(h)), the outlet angle at the shroud (beta2_(s)), and the angle of incidence at the shroud ( By extracting the values of i_beta_s), flow angle at the shroud (i_flow_s), angle of incidence at the hub (i_beta_h), and flow angle at the hub (i_flow_h), the tendency of the impeller design variables according to specific speed can be functionalized. .

Referring to Figures 9 to 11, in the present invention, the shape of the impeller of the optimized centrifugal pump at specific speeds of 50, 100, and 150 was derived, and the design variables at this time were extracted.

In the step of functionalizing the tendency of the design variables of the impeller according to specific speed, the tendency of the design variable can be functionalized using the numerical values of the design variables extracted for each specific speed. The design variable was non-dimensionalized as the design variable of the Ns50 class centrifugal pump impeller shape.

Through this, the angle of incidence (i_beta_h) at the hub can be derived from Equation 2 as follows.

Here _, Y _{1 is the} angle of incidence at the hub, It is a constant that is determined.

Preferably, when A ₁ is set to 0.000006, B ₁ to 0.0003, and C ₁ to 1, the incident angle (i_beta_h) at the hub optimized for each specific speed can be derived.

Referring to FIG. 10, the angle of incidence (i_beta_h) at the hub may tend to decrease as the specific speed increases.

Additionally, the flow angle (i_flow_h) at the hub can be derived from Equation 3 as follows.

Here _, Y _{2 is the} flow angle at the hub, It is a constant determined from .

Preferably, when A ₂ is set to 0.000024, B ₂ to 0.0061, and C ₂ to 0.75, the flow angle (i_flow_h) at the hub optimized for each specific speed can be derived.

Additionally, the angle of incidence (i_beta_s) at the shroud can be derived from Equation 4 as follows.

Here _, Y _{3 is the} angle of incidence at the shroud, It is a constant determined from .

Preferably, when A ₃ is set to 0.0000082, B ₃ to 0.0000000018, and C ₃ to 1.02, the angle of incidence (i_beta_s) at the shroud optimized for each specific speed can be derived.

Additionally, the flow angle (i_flow_s) at the shroud can be derived from Equation 5 as follows.

Here _, Y _{4 is} the flow _angle at the shroud, It is a constant determined from a range.

Preferably, when A ₄ is set to 0.0000065, B ₄ to 0.0021, and C ₄ to 0.91, the flow angle (i_flow_s) in the optimized shroud according to each specific speed can be derived.

Additionally, the exit angle (beta2_(h)) from the hub can be derived from Equation 6 as follows.

Here, Y _{5 is the} exit _angle from the hub, It is a constant determined from .

Preferably, when A ₅ is set to 0.00013, B ₅ to 0.024, and C ₅ to 0.101, the exit angle (beta2_(h)) from the hub optimized for each specific speed can be derived.

And, the exit angle (beta2_(s)) from the shroud can be derived from Equation 7 as follows.

Here _, Y _{6 is} the exit _angle from the shroud, It is a constant determined from a range.

Preferably, when A ₆ is set to 0.00013, B ₆ to 0.024, and C ₆ to 0.101, the exit angle (beta2_(s)) from the optimized shroud according to each specific speed can be derived.

As shown in Equation 2 to Equation 7, if the tendency of the design variable is functionalized and converted into a database (D/B), the optimized design variable for each specific speed can be output.

Figure 11 compares the efficiency of Ns50, Ns10, and Ns150 class centrifugal pump impellers. Efficiency was non-dimensionalized based on the efficiency of the Ns50 class centrifugal pump impeller shape, and the efficiency of the design flow rate of each shape was compared.

Referring to FIG. 11, the efficiency of the impeller may tend to increase as the specific speed increases.

By securing a database of various specific speeds and identifying the trends of design variables according to specific speed, it is possible to easily design an impeller shape for a centrifugal pump that satisfies the required design specifications and performance.

Figure 12 shows a procedure for designing a centrifugal pump impeller using design variable trends according to specific speed.

Referring to FIG. 12, since the tendency of the design variable of the centrifugal pump impeller according to the specific speed has been derived, when the specific speed is input, the centrifugal pump impeller shape can be designed using the design variable tendency according to the specific speed.

As a result, the low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention can design an impeller shape that can optimize the performance of the impeller for each design specification.

The low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance according to an embodiment of the present invention can design a pump impeller that satisfies efficiency for each specific speed using design variable tendencies.

Although the present invention has been described through preferred embodiments as described above, the present invention is not limited thereto and various modifications and variations are possible without departing from the concept and scope of the claims described below. Those working in the relevant technical field will easily understand.

S10: Design specification decision stage
S20: Specific speed determination step
S30: Design variable determination step
S40: 3D shape derivation step
1: Pump 2: Casing
3: Inlet 5: Discharge port
10: impeller 11: hub
13: Wing 15: Shroud
30: drive shaft

Claims (23)

In the impeller design method of a low specific speed centrifugal pump,
determining design specifications of the impeller;
determining a specific speed of the impeller;
determining design variables of the impeller;
Deriving the optimal shape of the impeller; and
It includes the step of functionalizing the tendency of the design variables of the impeller according to the specific speed,
The step of determining the design variables of the impeller is,
Determining design variables of a meridional plane representing the blade shape of the impeller; and
It includes the step of determining a design variable of the blade angle representing the blade angle of the impeller,
In the step of determining the design variable of the blade angle, the design variable of the blade angle is the total length of the meridional curve, the product of the sweep angle of the impeller and the average radius, the inlet angle, the outlet angle, the length of the inlet straight portion, the length of the outlet straight portion, Includes an angle inclined in the direction of rotation at the outlet,
The exit angle includes an exit angle at the hub and an exit angle at the shroud,
The entrance angle includes an entrance angle at the hub and an entrance angle at the shroud,
The entrance angle at the hub includes an incidence angle at the hub and a flow angle at the hub,
The entrance angle at the shroud satisfies the design specifications and performance including the angle of incidence at the shroud and the flow angle at the shroud,
The flow angle at the hub is,
^Y ₂ = _{- A 2
,} where Y _{2 is the} flow angle at the hub, A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which is a constant determined in the range of ∼0.8. According to claim 1,
In the step of determining the design specifications of the impeller, the design specifications are a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance of flow rate, head, and rotation speed. According to clause 2,
In determining the specific speed of the impeller, the specific speed is

, where Ns is the specific speed, Q is the flow rate, H is the head, n is the rotation speed,
The specific speed is a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance determined by the flow rate, head, and rotation speed. According to clause 3,
The specific speed is a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance determined in the range of 50 to 150. According to clause 4,
A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance of the impeller with five blades. According to clause 4,
The efficiency of the impeller is a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance with a tendency for each unit section according to the specific speed value in the range of 50 to 150. delete According to claim 1,
In the step of determining the design variable of the meridional plane, the design variable of the meridional plane is the radius of the hub portion at the inlet of the impeller, the radius of the shroud portion at the inlet of the impeller, the inclined angle of the blade front end of the impeller, A low specific speed centrifugal pump impeller that satisfies the design specifications and performance including the radius of the outlet of the impeller, the blade width at the rear end of the impeller, the inclined angle of the rear end of the blade, and the axial length of the shroud inlet and outlet. Wing angle distribution design method. According to clause 8,
The design variables of the meridional plane are the inlet angle and outlet angle formed by the shroud curve of the impeller with the horizontal and vertical lines, the inlet angle and outlet angle formed by the hub curve of the impeller with the horizontal and vertical lines, the outlet hub of the impeller, and The length of the straight part of the shroud, the shroud inlet adjustment point and outlet adjustment point, and the hub inlet adjustment point and outlet to create a Bezier curve from the end of the straight section of the outlet to the inlet of the impeller. Low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance including adjustment points. delete delete According to claim 1,
The angle of incidence at the hub is a low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance with a tendency for each unit section according to the specific speed value in the range of 50 to 150. According to claim 12,
The angle of incidence at the hub is
^Y ₁ = _{- A 1
,} where Y _{1 is the} angle of incidence at the hub, A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which are constants determined in the range of 1.1. delete According to claim 1,
The angle of incidence at the shroud is
Y _{3 = -} ^A ₃
, where Y _{3 is the angle} of incidence at the shroud, A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which are constants determined in the range of ~ 1.03. According to claim 1,
The flow angle at the shroud is
^Y ₄ = _{- A 4
,} where Y _{4 is} the flow angle at the _shroud , A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which are constants determined in the range of 0.9 to 1. According to claim 1,
The exit angle from the hub is
^Y ₅ = _{- A 5
,} where Y _{5 is} the exit _angle from the hub, A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which are constants determined in the range of ~ 0.11. According to claim 1,
The exit angle from the shroud is
Y _{6 = -} ^A _6
, where Y _{6 is} the exit _angle from the shroud, A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance, which are constants determined in the range of 0.1 to 0.11. According to claim 1,
The step of deriving the optimal shape of the impeller is,
Determining key design variables that affect the design objective value, which is the efficiency of the impeller; and
A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies design specifications and performance, including the step of identifying the conditions of optimal design variables that can optimize the design objective value by response surface technique. According to clause 19,
In the step of determining key design variables, the key design variables include outlet angle at the hub, outlet angle at the shroud, inlet angle at the shroud, inlet angle at the hub, and angle of incidence at the shroud. , A low specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance of the flow angle at the shroud, the incident angle at the hub, and the flow angle at the hub. According to claim 20,
Except for the main design variables, the remaining design variables are fixed to optimized values among the results obtained through the ^2k factorial experiment method and the response surface technique. A low-specific speed centrifugal pump impeller blade angle distribution design method that satisfies the design specifications and performance. A low specific speed centrifugal pump impeller that satisfies the design specifications and performance according to any one of claims 1 to 6, 8, 9, 12, 13, and 15 to 21. Impeller designed using the blade angle distribution design method. Impeller according to claim 22;
A pump including a casing in which the impeller is installed, a suction port formed to suck fluid into the front of the impeller, and an outlet formed to discharge the sucked fluid to the outer periphery of the impeller.