KR102531288B1 - Performance evaluating method of a centrifugal pump and computing device for performing the method - Google Patents

Abstract

Disclosed are a centrifugal pump performance evaluation method and a computing apparatus performing the same. The centrifugal pump performance evaluation method, in order to evaluate the performance of a centrifugal pump, includes the following steps of: determining an experimental plan with various clearances between a volute and an impeller constituting the centrifugal pump; providing a mesh structure for understanding fluid properties in a flow area in regard to a geometric model implemented according to the experimental plan; and evaluating the performance of the centrifugal pump corresponding to the geometric model by performing a numerical simulation to identify flow patterns in the geometric model for which the mesh structure has been provided. Therefore, the present invention is capable of quantitatively evaluating an influence of an axial clearance and a radial clearance on the performance of a centrifugal pump.

Description

Performance evaluation method of centrifugal pump and computing device performing the method

The present invention relates to a method for evaluating the performance of a centrifugal pump, and more particularly, to a method for evaluating the performance of a centrifugal pump according to a clearance between a volute and an impeller constituting the pump. it's about

Fluid flow inside a centrifugal pump can be very turbulent and complicated due to the relative motion between the impeller and the volute. do. Fluid interaction between the outlet of the impeller and the volute can generate pressure fluctuations and create unstable dynamic forces.

The performance of these centrifugal pumps can be greatly influenced by the shape of a complex passage area and the characteristics of the fluid pumped through the passage area. In particular, the axial clearance and the radial clearance between the impeller and the volute are provided in the centrifugal pump so that the impeller can freely rotate inside the volute, and can have a great effect on the performance of the centrifugal pump.

Previously, several studies have been conducted to show the effect of gap thickness on the performance of centrifugal pumps, but there is no study that quantitatively evaluates the effect of gap thickness and the effect of impeller and volute interaction on centrifugal pumps. there was

The present invention is to provide a method and apparatus for quantitatively evaluating the effect of the axial clearance and the radial clearance between the impeller and the volute of the centrifugal pump on the performance of the centrifugal pump.

In addition, the present invention is to provide a method and apparatus for quantitatively evaluating the effect of the characteristics of a fluid pumped through a flow path region of a centrifugal pump on the performance of the centrifugal pump.

However, the technical challenges are not limited to the above-described technical challenges, and other technical challenges may exist.

In order to evaluate the performance of a centrifugal pump according to an embodiment of the present invention, a clearance between a volute and an impeller constituting the centrifugal pump is configured in various ways. determining an experiment plan; providing a mesh structure for understanding fluid characteristics in a flow path region for a geometric model implemented according to the experimental plan; and evaluating performance of a centrifugal pump corresponding to the geometric model by performing a numerical simulation to identify a flow pattern in the geometric model provided with the mesh structure.

The determining of the experimental plan may include determining an experimental plan including at least one of an axial gap and a radial gap between a volute constituting the centrifugal pump and an impeller, and the axial direction and the radial direction may be perpendicular to each other. .

In the step of evaluating the performance of the centrifugal pump, fluids of different viscosities may be applied to the geometric model implemented according to the experimental plan, and flow patterns for each viscosity of the fluid may be identified.

Evaluating the performance of the centrifugal pump may include analyzing mechanical loss, volume loss, and hydraulic power loss of the centrifugal pump to determine mechanical efficiency, volumetric efficiency, and hydraulic power efficiency of the centrifugal pump, respectively; and calculating an overall efficiency of the centrifugal pump using the determined mechanical efficiency, volumetric efficiency, and hydraulic power efficiency.

The mechanical loss of the centrifugal pump is (i) the theoretical input power available from the shaft constituting the centrifugal pump without considering the axial clearance between the impeller and the volute constituting the centrifugal pump, and (ii) the ball It can be determined using the total power dissipated in the pumped fluid taking into account the friction loss in the axial clearance between the lute and the impeller.

The volume loss of the centrifugal pump may be determined using an available theoretical fluid flow rate without considering the axial and radial clearances between the impeller and the volute constituting the centrifugal pump.

The hydraulic power loss of the centrifugal pump uses (i) first head loss due to disc friction and (ii) second head loss due to leakage of the axial gap between the impeller and the volute constituting the centrifugal pump. can be determined by

The overall efficiency of the centrifugal pump may be determined as a product of mechanical efficiency, volumetric efficiency and hydraulic efficiency for the centrifugal pump.

A computing device for performing a method for evaluating the performance of a centrifugal pump according to an embodiment of the present invention includes a processor; a memory for loading a program executed by the processor; And a storage for storing the program, wherein the program configures a clearance between a volute and an impeller constituting the centrifugal pump in various ways in order to evaluate the performance of the centrifugal pump. An operation of determining an experimental plan, an operation of providing a mesh structure for understanding the fluid characteristics in the flow region for the geometric model implemented according to the experimental plan, and a flow pattern in the geometric model provided with the mesh structure It may include instructions for performing an operation of evaluating the performance of the centrifugal pump corresponding to the geometric model by performing a numerical simulation for identification.

The processor determines an experiment plan including at least one of an axial gap and a radial gap between the impeller and the volute constituting the centrifugal pump, and the axial direction and the radial direction may be perpendicular to each other.

The processor may apply fluids of different viscosities to the geometric model implemented according to the experimental plan and perform numerical simulation to identify a flow pattern for each viscosity of the fluid with respect to the geometric model.

The processor analyzes mechanical loss, volume loss, and hydraulic power loss of the centrifugal pump to determine mechanical efficiency, volume efficiency, and hydraulic power efficiency of the centrifugal pump, respectively, and uses the determined mechanical efficiency, volume efficiency, and hydraulic power efficiency to determine the The overall efficiency of a centrifugal pump can be calculated.

The mechanical loss of the centrifugal pump is (i) the theoretical input power available from the shaft constituting the centrifugal pump without considering the axial clearance between the impeller and the volute constituting the centrifugal pump, and (ii) the ball It can be determined using the total power dissipated in the pumped fluid taking into account the friction loss in the axial clearance between the lute and the impeller.

The volume loss of the centrifugal pump may be determined using an available theoretical fluid flow rate without considering the axial and radial clearances between the impeller and the volute constituting the centrifugal pump.

The hydraulic power loss of the centrifugal pump uses (i) first head loss due to disc friction and (ii) second head loss due to leakage of the axial gap between the impeller and the volute constituting the centrifugal pump. can be determined by

The overall efficiency of the centrifugal pump may be determined as a product of mechanical efficiency, volumetric efficiency and hydraulic efficiency for the centrifugal pump.

According to one embodiment of the present invention, the effect of the axial clearance and the radial clearance between the impeller and the volute of the centrifugal pump on the performance of the centrifugal pump can be quantitatively evaluated.

In addition, according to one embodiment of the present invention, it is possible to quantitatively evaluate the effect of the characteristics of the fluid pumped through the passage area of the centrifugal pump on the performance of the centrifugal pump.

대 유량 곡선을 도시한 도면이다.
도 11은 본 발명의 일실시예에 따른 유체 별 H _f 대 유량 곡선을 도시한 도면이다.
도 12는 본 발명의 일실시예에 따른 유체 별 H _l 대 유량 곡선을 도시한 도면이다.
도 13은 본 발명의 일실시예에 따른 서로 다른 점도를 가진 유체 별 수력 효율, 기계 효율 및 체적 효율을 도시한 도면이다.
도 14는 본 발명의 일실시예에 따른 간극에 따른 원심 펌프의 효율을 도시한 도면이다.1 is a diagram showing the configuration of a computing device according to an embodiment of the present invention.
2 is a flow chart showing a method for evaluating the performance of a centrifugal pump according to an embodiment of the present invention.
3 is a schematic diagram of a centrifugal pump for defining a gap between a volute constituting the centrifugal pump and an impeller according to an embodiment of the present invention.
4 is a diagram illustrating a meshing method of a centrifugal pump according to an embodiment of the present invention.
5 is a diagram showing a performance curve of a centrifugal pump obtained by performing numerical simulation according to an embodiment of the present invention.
6 is a diagram illustrating an example of setting a monitoring point according to an embodiment of the present invention.
7 is a diagram illustrating pressure pulsations measured at monitoring points during numerical simulation according to an embodiment of the present invention.
8 is a diagram showing a pressure pulsation curve at a monitoring point B1 for each case of a radial gap between a volute and an impeller according to an embodiment of the present invention.
9 is a diagram showing the effect of the volume loss Q _loss and the axial gap C _sh between the volute and the shroud side impeller according to an embodiment of the present invention.
10 is for each fluid according to an embodiment of the present invention

It is a diagram showing a large flow rate curve.
11 is a diagram illustrating an H _f vs. flow rate curve for each fluid according to an embodiment of the present invention.
12 is a diagram illustrating a H _l versus flow rate curve for each fluid according to an embodiment of the present invention.
13 is a diagram showing hydraulic efficiency, mechanical efficiency, and volumetric efficiency for each fluid having different viscosities according to an embodiment of the present invention.
14 is a diagram showing the efficiency of a centrifugal pump according to a gap according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only, and may be changed and implemented in various forms. Therefore, the form actually implemented is not limited only to the specific embodiments disclosed, and the scope of the present specification includes changes, equivalents, or substitutes included in the technical idea described in the embodiments.

Although terms such as first or second may be used to describe various components, such terms should only be construed for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element.

It should be understood that when an element is referred to as being “connected” to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this document, "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "A Each of the phrases such as "at least one of , B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof. In this specification, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, but one or more other features or numbers, It should be understood that the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this specification, it should not be interpreted in an ideal or excessively formal meaning. don't

The term "module" used in this document may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be an integrally constructed component or a minimal unit of components or a portion thereof that performs one or more functions. For example, according to one embodiment, the module may be implemented in the form of an application-specific integrated circuit (ASIC).

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a diagram showing the configuration of a computing device according to an embodiment of the present invention.

As shown in FIG. 1, the computing device 100 includes one or more processors 110, a memory 130 for loading a program 140 executed by the processor 110, and a program 140. It may include a storage 120 for storing. Components included in the computing device 100 of FIG. 1 are only examples, and those skilled in the art to which the present invention pertains may further include other general-purpose components in addition to the components shown in FIG. 1 . Able to know.

The processor 110 controls the overall operation of each component of the computing device 100 . The processor 110 may include at least one of a Central Processing Unit (CPU), a Micro Processor Unit (MPU), a Micro Controller Unit (MCU), a Graphic Processing Unit (GPU), or any type of processor well known in the art. can be configured to include Also, the processor 110 may perform an operation for at least one application or program for executing a method/operation according to various embodiments of the present disclosure. Computing device 100 may include one or more processors.

Memory 130 stores various data, commands and/or information. The memory 130 may load the program 140 stored in the storage 120 to execute methods/operations according to various embodiments of the present invention. An example of the memory 130 may be RAM, but is not limited thereto.

The storage 120 may non-temporarily store one or more programs 140 . The storage 120 may include nonvolatile memory such as read only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, a hard disk drive (HDD), a solid state disk (SSD), and a removable memory. It may be configured to include a disk, or any type of computer-readable recording medium well known in the art to which the present invention pertains.

Program 140 may include one or more actions in which methods/acts according to various embodiments of the present invention are implemented. Here, an operation corresponds to an instruction realized in the program 140 . For example, in order to evaluate the performance of the centrifugal pump, the program 140 determines an experiment plan in which clearances between impellers and volutes constituting the centrifugal pump are variously configured. , Performing an operation of performing a numerical simulation to identify a flow pattern in a geometric model implemented according to the experimental plan, and an operation of evaluating the performance of a centrifugal pump corresponding to the geometric model based on the numerical simulation performed. It may contain instructions to do so.

When the program 140 is loaded into the memory 130, the processor 110 may perform methods/operations according to various embodiments of the present disclosure by executing a plurality of operations for implementing the program.

An execution screen of the program 140 may be displayed through the display 150 . In the case of FIG. 1 , the display 150 is represented as a separate device connected to the computing device 100, but in the case of a computing device 100 such as a user-portable terminal such as a smartphone or a tablet, the display 150 may be a component of the computing device 100. The screen displayed on the display 150 may be before information is input to the program or a result of executing the program.

2 is a flow chart showing a method for evaluating the performance of a centrifugal pump according to an embodiment of the present invention.

The performance evaluation method of the centrifugal pump shown in FIG. 2 may be performed by the processor 110 of the computing device 100 . First, in step S110, the processor 110 may determine an experiment plan in which the gap between the impeller and the volute constituting the centrifugal pump is variously configured in order to evaluate the performance of the centrifugal pump.

As an example, a centrifugal pump may be implemented with a five-bladed impeller and a volute-type diffuser casing. However, the number of blades and the type of volute are only examples and are not limited to the above examples.

0) 할 수 있어야 하며, 원심 펌프의 방사상 방향 누출을 보장하기 위해 슈라우드 측면 임펠러 상단에 정밀 가공된 케이싱 링(casing ring)이 제공될 수 있다. 한편, 축 방향과 방사상 방향은 서로 직각일 수 있다.More specifically, FIG. 3 is a schematic diagram of a centrifugal pump for defining a gap between a volute and an impeller constituting the centrifugal pump of the present invention. Referring to Figure 3, the axial clearance between the volute and the shroud side impeller is C _sh , the axial clearance between the volute and the hub side impeller is C _h , and the axial clearance between the volute and the impeller is The radial direction gap can be represented by C _l . Ideally, there should be no leakage in the radial gap. Therefore, the radial clearance ( C _l ) provided to avoid leakage on the suction side of the centrifugal pump is neglected ( C _l

0), and a precision-machined casing ring may be provided at the top of the shroud side impeller to ensure radial leakage of the centrifugal pump. Meanwhile, the axial direction and the radial direction may be perpendicular to each other.

On the other hand, the axial clearance between the constituting volute and the impeller is the interval between the impeller and the volute that allows the impeller to freely rotate in the cavity of the volute, and the processor 110 is provided with an axial clearance as shown in Table 1 below. An experimental design including these variously configured geometric models can be determined. The experimental plan below is only an example and is not limited to the above example.

As an example, the present invention can generate the passage area of the geometric models included in the experimental plan using the ANSYS Bladegen model and the CATIA V5 module, but the device for generating such a geometric model is only one example and is not limited to the above example. don't

Model C _sh (mm) C _h (mm) C 0 None None C 0.2 0.25 0.5 C 0.5 0.50 0.5 C 0.7 0.75 0.5 C 1.0 1.00 0.5

In step S120, the processor 110 simulates fluid characteristics, that is, fluid flow in the flow path region for the geometric model implemented according to the experimental plan determined in this way, and analyzes the corresponding geometric model to understand the flow pattern. A mesh structure may be provided. More specifically, the passage area of the centrifugal pump may be implemented in different shapes of an impeller, a volute (casing), and a gap. Accordingly, as shown in FIG. 4, the processor 110 meshes the impeller and the volute with unstructured tetrahedral elements and prism elements because they have complex shapes, whereas the cavity area (gap) on the side of the hub and shroud has a simple shape, so it is structured It can be meshed with hexahedral elements. That is, the processor 110 creates a mesh with a fine grid on the front edge, the back edge, and the tongue area of the volute in order to more accurately predict the flow pattern in the passage area. while the rest of the area can be placed with a mesh with a less fine grid. As an example, such a mesh may be generated through an ANSYS CFX meshing module having an automatic mesh generation function, but this mesh generation device is only one example and is not limited to the above example.

In step S130, the processor 110 may evaluate the performance of the centrifugal pump corresponding to the geometric model by performing a numerical simulation to identify a flow pattern in the geometric model provided with the mesh structure. Here, the present invention uses the Navier Stokes equation according to the SST turbulence model (Shear Stress Transport Turbulence Model), and uses an up-wind method (Up -Wind) can be used. Accordingly, the fluid flow is constant and incompressible, and the Unsteady Reynolds Averaged Navier-Stokes Equations (RANS) equations to solve the numerical simulation of the centrifugal pump are as shown in Equations 1 and 2 below. can indicate

<Equation 1>

<Equation 2>

는 상대 속도 벡터이고

는 반경 위치

에서의 임펠러 각속도를 나타낸다. 그리고, 식 2는 x, y 및 z 방향의 운동량 보존 방정식으로 점성 응력(

)은 아래의 식 3과 같이 나타낼 수 있다.Here, Equation 1 is the mass conservation equation of an incompressible fluid,

is the relative velocity vector and

is the radial position

represents the impeller angular velocity at And, Equation 2 is the momentum conservation equation in the x, y, and z directions, and the viscous stress (

) can be expressed as in Equation 3 below.

<Equation 3>

와

는 각각 유체 점도와 평균 변형률 텐서의 곱을 나타낼 수 있고, 유입 경계 조건과 유출 경계 조건은 각각 잔류 목표물 1x10^-4의 수렴을 기준으로 총압력과 질량유량으로 설정할 수 있다.Equation 3 above may represent a tensor quantity that is a combination of viscosity and turbulent viscosity terms. here,

and

can represent the product of the fluid viscosity and the average strain tensor, respectively, and the inflow boundary condition and the outflow boundary condition can be set as the total pressure and mass flow rate, respectively, based on the convergence of the residual target 1x10 ^-4 .

Meanwhile, the numerical simulation provided by the present invention may provide numerical simulation parameters as shown in Table 2 below. The processor 110 may apply fluids of different viscosities to the geometric models implemented according to the experimental plan based on the numerical simulation parameters. And, through this, the processor 110 may identify a flow pattern for each flow path area for each viscosity of the fluid for each geometric model. At this time, the numerical simulation parameters according to Table 2 are only one example and are not limited to the following examples.

Parameters Descriptions Flow domains Impeller, Volute casing, Hub and Shroud cavities Interface Frozen rotor Mesh types Unstructured at impeller and casing; Structured at Shroud and hub cavities Total elements used 2.5 million decided by grid independency test Residual convergence value ^1x10-4 Mass imbalance 0.0001kg/s

Meanwhile, the processor 110 may evaluate the performance of the centrifugal pump by performing numerical simulation by applying different conditions to the radial gap C _l between the volute and the impeller. More specifically, the processor 110 includes (i) no radial gap C _l (no_cl), (ii) a radial gap C _l but no leakage (cl_nl), and (iii) a radial gap C _l . It is possible to obtain the performance curve of the centrifugal pump as shown in FIG. 5 by performing numerical simulation for the case where there is leakage (cl_l) while there exists. As an example, in FIG. Crude oil C1, crude oil C2 with a viscosity of 26 Cp. Referring to FIG. 5 , it can be seen that the performance curve of the centrifugal pump obtained through numerical simulation deviates more from C2, which has a higher viscosity than water, due to high disk friction loss.

At this time, the processor 110 may perform numerical simulation by setting three monitoring points as shown in FIG. 6 to capture unstable flow patterns and pressure pulsations occurring at the interface between the impeller and the volute for various fluid cases. More specifically, the monitoring point may be disposed inside the volute casing at a predetermined distance from the impeller tip as shown in FIG. 6 . Here, point B1 is used to monitor the outlet pressure of the impeller case, and points B2 and B3 can be used to measure the pressure entering the gap on the side of the shroud and the gap on the side of the hub, respectively.

7 is a diagram illustrating pressure pulsations measured at monitoring points B1, B2, and B3 during numerical simulation for water and fluid C2 according to an embodiment of the present invention. Referring to (a) and (b) of FIG. 7 , it can be seen that the pressure intensities of monitoring points B1 and B2 are higher compared to monitoring point B3 on the hub side, which is normally closed so that fluid cannot pass through the gap.

Also, the shroud side may be provided with a small radial clearance to allow the impeller to rotate in the inner cavity of the volute casing. At this time, since the viscosity of the fluid C2 is higher than that of water, it can be seen that the pressure pulsation in the case of the fluid C2 is relatively stable compared to the case of water due to the viscosity of the fluid.

8 is a diagram showing a pressure pulsation curve at a monitoring point B1 for each case of a radial gap between a volute and an impeller according to an embodiment of the present invention. More specifically, (a), (b), and (c) of FIG. 8 show (i) a case where there is no radial gap C _l (no_cl), (ii) a radial gap for each of water, C1, and C2, which are fluids. The pressure pulsation curves at the monitoring point B1 obtained by performing numerical simulations considering (iii) the case where C _l exists but no leakage (cl_nl) and (iii) the radial gap C _l exists and there is leakage (cl_l) are indicate

Referring to FIG. 8 , (i) when there is no radial gap C _l (no_cl), it can be seen that the fluctuation of pressure pulsation is serious for all fluid cases. This is because the back pressure generated on the opposite side of the wall of the volute casing creates a huge turbulence at the junction of the impeller and the volute casing. However, (ii) when there is a radial gap C _l but no leakage (cl_nl) and (iii) when there is a radial gap C _l and there is leakage (cl_l), the back pressure is stabilized when the fluid flows into the radial gap The back pressure may not be critical because it becomes stable and brings stability to the junction of the impeller and the volute casing.

As an example, FIG. 15 is a diagram illustrating an interaction area between back pressure, an impeller, and a volute casing according to an embodiment of the present invention. 15 shows a vector plot in the z-plane of the centrifugal pump region showing the meridional velocity vector. In this case, the length of the arrow of the vector may represent the size.

More specifically, FIG. 15 (a) is a diagram comparing z-plane vectors for the no_cl case, and FIG. 15 (b) is a diagram comparing z-plane vectors for the cl_nl case. Referring to (a) of FIG. 15 , it can be seen that the impeller outlet speed rotates in the casing passage due to the relative motion of the impeller and the volute casing. Here, in the case of viscous fluid C2, a vortex structure appears on the volute cross section, which is larger in the case of no_cl and smaller in the case of cl_nl.

Referring to (b) of FIG. 15 , it can be seen that the pressure generated in the volute casing part due to the gap flow region is distributed to the gap region and the back pressure causing the interaction between the impeller and the volute casing is reduced.

In addition, referring to FIG. 8 , it can be confirmed that the increase in the viscosity of the fluid reduces the pressure pulsation at the monitoring point B1 but affects the average pressure rise of the centrifugal pump at the impeller outlet.

Referring to the above numerical simulation results, it can be seen that the hydraulic power loss and volume loss of the centrifugal pump are related to the shape and fluid characteristics of the passage area through which the pumped fluid moves, and these losses may be referred to as internal losses. In addition, mechanical loss representing a decrease in mechanical power due to friction between the rotating parts of the centrifugal pump, i.e., the volute and the impeller, may be referred to as external loss. Below we can provide a method for quantitatively calculating the internal and external losses of such a centrifugal pump.

First, the volume loss Q _loss can be caused by design flaws or leakage through gaps. The fluid that has passed through the gap returns to the inlet of the impeller and causes a secondary flow, which can reduce the volumetric efficiency and overall performance of the centrifugal pump.

At this time, in order to calculate the volume efficiency, the processor 110 calculates the available theoretical fluid flow rate Q _th without considering the axial clearance and the radial clearance between the impeller and the volute constituting the centrifugal pump as shown in Equation 4 below. You have to find it.

<Equation 4>

는 누출이 없다고 가정한 원심 펌프의 이상적인 유량인 반면 실제 유량(

)은 누출로 인해

보다 작을 수 있다. 따라서,

혹은

를 계산하려면

가 추가되어야 한다.here,

is the ideal flow rate of a centrifugal pump, assuming no leaks, whereas the actual flow rate (

) due to leakage

may be smaller than thus,

or

To calculate

should be added.

The effect of the calculated volume loss Q _loss and the axial clearance C _sh between the volute and shroud side impellers can be seen in FIG. 9 . Referring to FIG. 9, it can be seen that the effect of C _sh on Q _loss follows a similar trend for all fluids having different viscosities. Here, it is confirmed that Q _loss is no longer affected by C sh as C _sh approaches _0.5 mm. This is due to _the pressure normalization of the volute casing in the region _of Csh , so that further increase in Csh may not affect the Q _loss .

Also, referring to FIG. 9 , the Q _loss of fluids C1 and C2 having higher viscosities than that of water may be reduced compared to that of water. This may be due to the formation of fluid rotation caused by viscous forces that create a natural seal in the C _sh region.

)은 한 구성 요소에서 다른 구성 요소로 기계적 에너지를 전달할 때 발생하는 전력 손실을 포함할 수 있다. 여기서

는 유체와 임펠러의 허브 측면 및 슈라우드 측면 사이의 디스크 마찰, 베어링 및 샤프트 씰의 손실로 인해 발생될 수 있다.mechanical loss (

) can include power losses that occur when transferring mechanical energy from one component to another. here

can be caused by disc friction between the fluid and the hub and shroud sides of the impeller, loss of bearings and shaft seals.

The processor 110 may estimate power loss due to disk friction through torque calculation through a numerically simulated model as shown in Equation 5 below.

<Equation 5>

는 원심 펌프를 구성하는 볼류트와 임펠러 사이의 축 방향 간극을 고려하지 않고 원심 펌프를 구성하는 샤프트에서 사용할 수 있는 이론적인 전력 소비이고,

는 볼류트와 임펠러 사이의 축 방향 간극의 마찰 손실을 고려하여 원심 펌프를 작동하는 동안 소비되는 실제적인 전력 소비를 나타낼 수 있다.here,

is the theoretical power consumption available in the shaft constituting the centrifugal pump without considering the axial clearance between the impeller and the volute constituting the centrifugal pump,

can represent the actual power consumption consumed while operating the centrifugal pump, taking into account the frictional loss of the axial clearance between the volute and the impeller.

대 유량 곡선을 도시한 도면이다. 도 10을 참고하면,

는 설계 지점까지 선형적으로 증가하고 그 이후에는 기하급수적으로 증가하는 것을 알 수 있다.10 is for each fluid according to an embodiment of the present invention

It is a diagram showing a large flow rate curve. Referring to Figure 10,

It can be seen that increases linearly up to the design point and then increases exponentially.

Hydraulic loss ( H _loss ) is the pressure drop caused by shock loss, secondary loss, separation and recirculation loss, and disc friction loss that are affected by the fluid viscosity and the structural design of the flow area.

The theoretical hydraulic power ( H _th ) consumed by the centrifugal pump is the power estimated through numerical analysis of the flow region without gaps, and the total hydraulic power loss can be estimated as shown in Equation 6 below.

<Equation 6>

At this time, H _f means a first head loss due to disc friction, and H _l means a second head loss due to leakage of an axial gap between the impeller and a volute constituting the centrifugal pump. At this time, H _f and H _l can be calculated through numerical simulations for a flow region with a gap in which leakage is not allowed and a gap in which leakage is allowed, respectively.

11 is a diagram illustrating a H _f versus flow rate curve for each fluid according to an embodiment of the present invention, and FIG. 12 is a diagram illustrating a H _l versus flow rate curve for each fluid according to an embodiment of the present invention. More specifically, FIG. 11 shows the effect of each loss on the flow rate, where it can be observed that H _f first decreases and then the design flow rate increases rapidly, and FIG. 12 shows H _l indicates that is kept almost constant until the design flow rate is increased. At this time, the design flow rate represents the pump flow rate at the best efficiency point (BEP).

It is also seen that the H _f of the viscous fluid C2 is much higher than that of the other fluids, but the opposite is true for H _l . As discussed above, H _f is more dominant in high-viscosity fluids compared to low-viscosity fluids due to an increase in disc friction losses, but for H _l , the effect of head losses can be reversed.

) 및 체적 효율(η _v )을 아래의 식 7 내지 식 9를 통해 각각 결정할 수 있으며, 식 10을 통해 원심 펌프의 전체 효율(

을 계산할 수 있다.Finally, the processor 110 includes the hydraulic efficiency of the centrifugal pump ( η _h ), mechanical efficiency (

) and volume efficiency ( η _v ) can be determined through Equations 7 to 9 below, respectively, and the overall efficiency of the centrifugal pump through Equation 10 (

can be calculated.

<Equation 7>

<Equation 8>

<Equation 9>

<Equation 10>

13 is a diagram showing hydraulic efficiency, mechanical efficiency, and volumetric efficiency for each fluid having different viscosities according to an embodiment of the present invention. Referring to FIG. 13 , it can be seen that the volumetric efficiency increases slightly up to the design point, which means the optimal efficiency point (BEP) of the centrifugal pump, but the repair efficiency greatly increases. Here, it can be seen that the volumetric efficiency of the viscous fluid is slightly affected by the viscosity, but the hydraulic power loss due to disk friction and the pressure drop due to leakage have a large effect on the efficiency of the centrifugal pump.

은 간극(C _l)의 변화로 인해 수리 효율(

)보다 덜 민감한 것을 알 수 있다.14 is a diagram showing the efficiency of a centrifugal pump according to a gap according to an embodiment of the present invention. Referring to (a) and (b) of FIG. 14, the volumetric efficiency (

The repair _efficiency (

) is less sensitive than

Here, it can be seen that the decrease in volumetric efficiency occurs more in water than in the other fluids (C1 and C2), while the decrease in hydraulic efficiency of fluid C2 is the highest compared to water and fluid C1. This shows a significant influence of clearance on the performance of a centrifugal pump in relation to the viscosity of the fluid.

The embodiments described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. For example, the devices, methods and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate (FPGA). array), programmable logic units (PLUs), microprocessors, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and software applications running on the operating system. A processing device may also access, store, manipulate, process, and generate data in response to execution of software. For convenience of understanding, there are cases in which one processing device is used, but those skilled in the art will understand that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it can include. For example, a processing device may include a plurality of processors or a processor and a controller. Other processing configurations are also possible, such as parallel processors.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. You can command the device. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on computer readable media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. A computer readable medium may store program instructions, data files, data structures, etc. alone or in combination, and program instructions recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in the art of computer software. there is. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler.

The hardware device described above may be configured to operate as one or a plurality of software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on this. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

100: computing device
110: processor
120: storage
130: memory
140: program
150: display

Claims (16)

In order to evaluate the performance of the centrifugal pump, determining an experiment plan consisting of various configurations of clearances between a volute and an impeller constituting the centrifugal pump;
providing a mesh structure for understanding fluid characteristics in a flow path region for a geometric model implemented according to the experimental plan; and
Evaluating the performance of a centrifugal pump corresponding to the geometric model by performing a numerical simulation to identify a flow pattern in the geometric model provided with the mesh structure.
including,
Providing the mesh structure,
The volute and the impeller constituting the centrifugal pump are meshed with unstructured tetrahedral elements and prism elements, and the axial gap between the volute and the shroud side impeller and the volute and the hub side side The axial gap between the impellers is meshed with structured hexahedral elements,
Evaluating the performance of the centrifugal pump,
<Equation 2>

Based on (i) the relative velocity vector (

), (ii) impeller angular velocity at a specific radial position (

) and (iii) fluid viscosity (

) and the average strain tensor (

), which can be expressed as a product of viscous stress (

) Evaluate the performance of the centrifugal pump corresponding to the geometric model through numerical simulation using,
The viscous stress is
<Equation 3>

Method for evaluating the performance of centrifugal pumps calculated by According to claim 1,
The step of determining the experimental plan,
Determine an experimental plan including at least one of an axial gap and a radial gap between a volute constituting the centrifugal pump and an impeller,
A method for evaluating the performance of centrifugal pumps in which the axial and radial directions are orthogonal to each other. According to claim 1,
Evaluating the performance of the centrifugal pump,
A method for evaluating the performance of a centrifugal pump in which fluids of different viscosities are applied to the geometric model implemented according to the experimental plan to identify a flow pattern for each viscosity of the fluid for the geometric model. According to claim 1,
Evaluating the performance of the centrifugal pump,
analyzing mechanical loss, volume loss and hydraulic power loss of the centrifugal pump to determine mechanical efficiency, volumetric efficiency and hydraulic power efficiency of the centrifugal pump, respectively; and
Calculating the overall efficiency of the centrifugal pump using the determined mechanical efficiency, volumetric efficiency and hydraulic power efficiency
Performance evaluation method of a centrifugal pump comprising a. According to claim 1,
Evaluating the performance of the centrifugal pump,
(i) there is no radial gap between the volute and the impeller, (ii) there is a radial gap between the volute and the impeller but no leakage, and (iii) a radial gap between the volute and the impeller. A centrifugal pump performance evaluation method for obtaining a performance curve of the centrifugal pump by performing numerical simulations for each case where there is a gap and leakage. delete According to claim 4,
The hydraulic power loss of the centrifugal pump is,
Performance of the centrifugal pump determined using (i) first head loss due to disk friction and (ii) second head loss due to leakage of the axial clearance between the impeller and the volute constituting the centrifugal pump Assessment Methods. According to claim 4,
The overall efficiency of the centrifugal pump is,
A method for evaluating the performance of a centrifugal pump determined by the product of mechanical efficiency, volumetric efficiency and hydraulic power efficiency for the centrifugal pump. In a computing device,
processor;
a memory for loading a program executed by the processor; and
Including a storage for storing the program, wherein the program,
In order to evaluate the performance of the centrifugal pump, the operation of determining an experimental plan that variously configures the clearance between the impeller and the volute constituting the centrifugal pump, the geometrical implementation according to the experimental plan The geometric model by performing an operation of providing a mesh structure for understanding the fluid characteristics in the flow area to the model and a numerical simulation to identify a flow pattern in the geometric model provided with the mesh structure. Includes instructions for performing an operation of evaluating the performance of the centrifugal pump corresponding to
the processor,
The volute and the impeller constituting the centrifugal pump are meshed with unstructured tetrahedral elements and prism elements, and the axial gap between the volute and the shroud side impeller and the volute and the hub side side The axial gap between the impellers is meshed with structured hexahedral elements,
<Equation 2>

Based on (i) the relative velocity vector (

), (ii) impeller angular velocity at a specific radial position (

) and (iii) fluid viscosity (

) and the average strain tensor (

), which can be expressed as a product of viscous stress (

) Evaluate the performance of the centrifugal pump corresponding to the geometric model through numerical simulation using,
The viscous stress is
<Equation 3>

Computing device computed by. According to claim 9,
the processor,
Determine an experimental plan including at least one of an axial gap and a radial gap between a volute constituting the centrifugal pump and an impeller, wherein an axial direction and a radial direction are perpendicular to each other. According to claim 9,
the processor,
A computing device for performing numerical simulation to identify a flow pattern for each viscosity of the fluid for the geometric model by applying fluids of different viscosities to the geometric model implemented according to the experimental plan. According to claim 9,
the processor,
Mechanical efficiency, volumetric efficiency, and hydraulic power efficiency of the centrifugal pump are determined by analyzing mechanical loss, volume loss, and hydraulic power loss of the centrifugal pump, and A computing device that calculates overall efficiency. According to claim 12,
the processor,
(i) there is no radial gap between the volute and the impeller, (ii) there is a radial gap between the volute and the impeller but no leakage, and (iii) a radial gap between the volute and the impeller. A computing device for obtaining a performance curve of the centrifugal pump by performing numerical simulations for each case where there is a gap and leakage. delete According to claim 12,
The hydraulic power loss of the centrifugal pump is,
(i) a first head loss due to disc friction and (ii) a second head loss due to leakage of an axial gap between the impeller and the volute constituting the centrifugal pump. According to claim 12,
The overall efficiency of the centrifugal pump is,
A computing device determined as the product of mechanical efficiency, volumetric efficiency and hydraulic power efficiency for the centrifugal pump.

Images