Calculation method of shape and material loss of water pump blade cavitation erosion area under sand-entrained condition

Abstract

The present application relates to the technical field of water pump engineering, and provides a calculation method for the shape of cavitation erosion area and material loss of water pump blades under sand-carrying conditions, which comprises the following specific steps: determining characteristic parameters, carrying out transient numerical simulation on the research object to determine the cavitation area and obtain relevant flow field parameters; introducing flow velocity correction factor and sand-carrying correction factor to respectively reflect the influence of water flow velocity and sand particles on the material loss of cavitation erosion; calculating the cavitation erosion offset distance, and determining the shape of the cavitation erosion area according to the cavitation erosion offset distance and the geometric profile of the cavitation area; and calculating the material loss of the cavitation erosion area by using the flow velocity correction factor and the sand-carrying correction factor. For a given water pump, the present application can quickly and accurately predict the shape of the cavitation erosion area and the material loss of the blades under different sand-carrying working conditions, and solves the problem that the existing method cannot accurately predict the shape of the cavitation erosion area and the material loss of the water pump blades under sand-carrying conditions, thereby providing effective protection for the cavitation erosion protection of water pumps under sand-carrying conditions.

Description

Technical Field

[0001] The invention relates to the technical field of water pump engineering, and in particular to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions. Background Art

[0002] Existing predictions of cavitation in pump blades often rely on cavitation calculations, and engineering practices often equate the cavitation zone with the cavitation zone. However, existing research indicates that the actual cavitation zone is offset relative to the cavitation zone in the flow direction and is particularly affected by water velocity and sediment particles. Existing cavitation assessment methods fail to quantitatively account for these influencing factors and generally only assess cavitation risk, failing to accurately calculate the amount of material loss caused by cavitation. Summary of the Invention

[0003] The present invention provides a method for calculating the shape of the cavitation zone and the amount of material loss of water pump blades under sand-carrying conditions, which is used to solve the problem that the cavitation assessment methods in the related art fail to quantitatively consider these influencing factors and generally can only achieve the assessment of cavitation risk, but it is difficult to accurately calculate the amount of material loss caused by cavitation.

[0004] The present invention provides a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions, comprising:

[0005] Determine the relevant characteristic parameters of the shape of the cavitation zone of the water pump blade and the amount of material loss under the condition of sand entrainment, wherein the relevant characteristic parameters include at least the cavitation time t , sediment concentration α , sand particle size d , material density ρ ;

[0006] In the process of spatial discretization of the object to be used for calculating the shape of the cavitation zone and the amount of material loss, a transient numerical simulation is carried out, the cavitation zone is determined by the results of the numerical simulation, and the relevant flow field parameters are obtained, the relevant flow field parameters at least including the flow velocity V , cavitation zone area A c , the maximum flow length of the cavitation zone l max ;

[0007] Introducing flow rate correction factors C V and sediment correction factor C P , wherein the velocity correction factor C V and sediment correction factor C P Respectively reflect the effects of water flow velocity and sediment particles on the amount of cavitation material loss;

[0008] Calculate the cavitation offset distance Δ l , and determine the shape of the cavitation area, wherein the cavitation offset distance Δ l It is used to reflect the displacement of the cavitation zone relative to the cavitation zone in the flow direction;

[0009] Based on the flow rate correction factor C V and the sediment correction factor C P , calculate the material loss in the cavitation zone E , wherein the material loss in the cavitation zone is E To reflect the cumulative material loss of the pump blades due to continuous cavitation.

[0010] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the method includes: performing spatial discretization on an object for which the shape of the cavitation zone and the amount of material loss are to be calculated, performing transient numerical simulation, determining the cavitation zone through the results of the numerical simulation, and obtaining relevant flow field parameters, including:

[0011] The finite volume method is used to spatially discretize the object for calculating the shape of the cavitation zone and the amount of material loss.

[0012] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the method further includes: determining the cavitation zone and obtaining relevant flow field parameters during the spatial discretization of the object for which the cavitation zone shape and material loss calculation are to be performed.

[0013] Select a computational model to carry out transient numerical simulation and obtain numerical simulation results;

[0014] Based on the numerical simulation results, the cavitation region is determined, and the relevant flow field parameters are obtained therefrom.

[0015] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the selected calculation models include the ZGB cavitation model and the SSTk-ω turbulence model.

[0016] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, in the process of spatially discretizing the object to be used for calculating the shape of the cavitation zone and the amount of material loss, the cavitation zone is determined and the relevant flow field parameters are obtained. The relevant flow field parameters include at least the flow velocity V , cavitation zone area A c , the maximum flow length of the cavitation zone l max Also included:

[0017] The stream velocity V The magnitude is equal to the average axial velocity of the blade inlet edge, and its direction is perpendicular to the axial plane of the blade inlet edge.

[0018] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the velocity correction factor is determined by expression 1: C V , which is calculated as follows:

[0019] Expression 1:

[0020] ;

[0021] Among them, the expression in V is the stream velocity, 1 is the velocity increment base, 1.78×10 -4 , 2.2 is the flow rate increment coefficient.

[0022] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand entrainment conditions provided by the present invention, the sand entrainment correction factor is determined by expression 2: C P , which is calculated as follows:

[0023] Expression 2:

[0024] ;

[0025] Among them, in expression 2 α is the sediment concentration, d is the particle size of the entrained sand, 1 is the sediment-affected base, -0.005, 0.52, -4.2×10 -5 , -1.62, and 0.044 are all sediment influence coefficients.

[0026] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the cavitation offset distance Δ l , and determining the shape of the cavitation zone, including:

[0027] According to the cavitation offset distance Δ l and the geometric outline of the cavitation zone to determine the shape of the cavitation zone.

[0028] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the cavitation offset distance Δ is determined by expression 3: l , which is calculated as follows:

[0029] Expression three:

[0030] ;

[0031] Among them, in expression three V is the flow velocity, l max is the maximum flow length of the cavitation zone, and 0.022, 1, and 2 are cavitation offset coefficients.

[0032] According to a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions provided by the present invention, the amount of material loss in the cavitation zone is expressed as follows: E , the calculation method is:

[0033] Expression 4:

[0034] ;

[0035] Among them, in expression 4, is the average cavitation material loss rate, ρ is the material density, A e is the area of ​​cavitation zone, and is the area of ​​cavitation zone A c equal, t 1 is the start time of the stage, t 2 is the end time of the stage, t is the cavitation time, 1.454×10 -6 , 0.34, 150, 8.8 are the material loss influence coefficients in the cavitation acceleration stage, 7.74×10 -7 , -1110, 231 is the material loss influence coefficient in the cavitation weakening stage, 3.47×10 -7 is the average material loss rate in the stable stage of cavitation.

[0036] The present invention provides a method for calculating the shape of the cavitation zone and the amount of material loss of water pump blades under sand-carrying conditions, which comprehensively considers the influence of water flow velocity and sediment particles on cavitation. For a given water pump, the shape of the cavitation zone and the amount of material loss of its blades under different water flow velocities, sediment concentrations, and sediment particle sizes can be quickly and accurately predicted. This solves the problem that existing methods are difficult to accurately predict the shape of the cavitation zone and the amount of material loss of water pump blades under sand-carrying conditions, and provides effective protection for cavitation protection and safe and stable operation of water pumps under sand-carrying conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to make the technical solutions in the present application or the related art clearer, the accompanying drawings needed in the embodiments or the related description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative work based on the accompanying drawings also belong to the protection scope of the present application.

[0038] Figure 1 is the implementation flowchart of the calculation method of the shape of the cavitation erosion area of the water pump blade under the sand-carrying condition and the material loss amount provided by the present application.

[0039] Figure 2 is the calculation distribution diagram of the cavitation area and the cavitation erosion area of the water pump blade provided by the present application.

[0040] Figure 3 is the experimental distribution diagram of the cavitation erosion area of the water pump blade provided by the present application.

[0041] Figure 4 is the change relationship diagram of the material loss amount of the cavitation erosion area of the water pump blade with time provided by the present application.

[0042] Figure 5 is the schematic diagram of expression one provided by the present application.

[0043] Figure 6 is the schematic diagram of expression two provided by the present application.

[0044] Figure 7 is the schematic diagram of expression three provided by the present application.

[0045] Figure 8 is the schematic diagram of expression four provided by the present application. DETAILED DESCRIPTION

[0046] In order to make the technical solutions in the present application or the related art clearer, the accompanying drawings needed in the embodiments or the related description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative work based on the accompanying drawings also belong to the protection scope of the present application.

[0047] The present application will be described below in combination with Figures 1-8 a calculation method of the shape of the cavitation erosion area of the water pump blade under the sand-carrying condition and the material loss amount.

[0048] As Figure 1The figure shows a flow chart of the method for calculating the shape of the cavitation zone and the amount of material loss of the water pump blades under the condition of sand entrainment provided by the present invention. A centrifugal pump model is used as an embodiment of this patent. The impeller diameter of the centrifugal pump is 0.427m and the number of blades is 6. In terms of operating conditions, the flow rate is 800m 3 / h, the speed is 1480rpm, and the effective cavitation margin is 8.8m.

[0049] An embodiment of the present invention provides a method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand entrainment conditions, comprising:

[0050] Step 1: Determine the relevant characteristic parameters of the shape of the cavitation zone and material loss of the pump blade under sand-carrying conditions. The relevant characteristic parameters include at least the cavitation time. t , sediment concentration α , sand particle size d , material density ρ ;

[0051] Specifically, in the embodiment of the present invention, the relevant characteristic parameters of the shape of the cavitation zone and the amount of material loss of the water pump blade under the condition of sand entrainment are clearly calculated. The relevant characteristic parameters can be obtained by sampling and measuring the specific engineering environment, among which the cavitation time t =0~2500min, sediment concentration α =10kg / m 3 , sand particle size d =2.5×10 -5 m, material density ρ =7930kg / m 3 ;

[0052] Step 2: During the spatial discretization of the object for which the cavitation zone shape and material loss calculation is to be carried out, transient numerical simulation is carried out, the cavitation zone is determined by the results of numerical simulation, and relevant flow field parameters are obtained. The relevant flow field parameters include at least the flow velocity. V , cavitation zone area A c , the maximum flow length of the cavitation zone l max ;

[0053] Step 3: Introducing a velocity correction factor C V and sediment correction factor C P , where the velocity correction factor is C V and sediment correction factor C P Respectively reflect the effects of water flow velocity and sediment particles on the amount of cavitation material loss;

[0054] Step 4: Calculate the cavitation offset distance Δ l , and determine the shape of the cavitation area, where the cavitation offset distance Δ l It is used to reflect the displacement of the cavitation zone relative to the cavitation zone in the flow direction;

[0055] Step 5: Flow rate correction factor C V and sediment correction factor C P , calculate the material loss in the cavitation zone E , where the material loss in the cavitation zone is E To reflect the cumulative material loss of the pump blades due to continuous cavitation.

[0056] The present invention provides a method for calculating the shape of the cavitation zone and the amount of material loss of water pump blades under sand-carrying conditions, which comprehensively considers the influence of water flow velocity and sediment particles on cavitation. For a given water pump, the shape of the cavitation zone and the amount of material loss of its blades under different water flow velocities, sediment concentrations, and sediment particle sizes can be quickly and accurately predicted. This solves the problem that existing methods are difficult to accurately predict the shape of the cavitation zone and the amount of material loss of water pump blades under sand-carrying conditions, and provides effective protection for cavitation protection and safe and stable operation of water pumps under sand-carrying conditions.

[0057] In this embodiment, the cavitation time is clearly calculated by measuring t , sediment concentration α , sand particle size d and material density ρ and other data, and further determine the velocity correction factor C V and sediment correction factor C P , and based on the flow rate correction factor C V and sediment correction factor C P , further calculations are performed to obtain the material loss E in the cavitation zone; based on the flow velocity V and the maximum flow length of the cavitation zone l max , calculate the cavitation offset distance Δ l , further calculations determine the shape of the cavitation zone.

[0058] In an embodiment of the present invention, in step 2, in the process of spatially discretizing the object for which the cavitation zone shape and material loss amount are to be calculated, the cavitation zone is determined and relevant flow field parameters are obtained, including: using the finite volume method to spatially discretize the object for which the cavitation zone shape and material loss amount are to be calculated.

[0059] It can be understood that the finite volume method recognized in the field of water pumps can be used to spatially discretize the object to be used for the calculation of the cavitation zone shape and material loss, and then directly used for the numerical calculation of the cavitation zone shape and material loss to obtain the flow velocity. V , cavitation zone area A c It should be noted that in the actual calculation process, the order of each step can be adjusted according to actual needs and is not limited here.

[0060] In this embodiment, step 2, during the spatial discretization of the object for which the cavitation zone shape and material loss calculation are to be performed, determines the cavitation zone and obtains relevant flow field parameters. The method also includes: selecting a computational model to conduct transient numerical simulations and obtain numerical simulation results; and based on the numerical simulation results, determines the cavitation zone and obtains relevant flow field parameters. Specifically, the computational models selected include the ZGB cavitation model and the SSTk-ω turbulence model. Furthermore, by making the numerical simulation results more consistent with experimental values, flow information in turbulent flows can be more accurately obtained, making it more suitable for flow calculations within hydraulic machinery.

[0061] In the embodiment of the present invention, further, in step 2, in the process of spatial discretization of the object to be used for calculating the cavitation zone shape and material loss, the cavitation zone is determined and the relevant flow field parameters are obtained. The relevant flow field parameters include at least the flow velocity V , cavitation zone area A c , the maximum flow length of the cavitation zone l max Also includes: flow velocity V The magnitude is equal to the average axial velocity of the blade inlet edge, and its direction is perpendicular to the axial plane of the blade inlet edge.

[0062] In the embodiment of the present invention, further, in step three, as Figure 5 As shown, the velocity correction factor is determined by expression 1. C V , which is calculated as follows:

[0063] Expression 1:

[0064] ;

[0065] Among them, the expression in V is the stream velocity, 1 is the velocity increment base, 1.78×10 -4, 2.2 is the velocity increment coefficient. It can be understood that the derivation steps of Expression 1 are as follows: (1) Based on the study of the influence of velocity on cavitation damage in classic experiments, the relationship between the degree of cavitation damage and flow velocity is obtained through fitting analysis; (2) Based on this relationship, it is deduced that the cavitation damage increment ratio caused by unit velocity change is 1.78×10 -4 · V 2.2 , and the velocity correction factor is obtained based on the increment ratio C V .

[0066] In the embodiment of the present invention, further, in step three, as Figure 6 As shown in the following expression, the sediment correction factor is determined by C P , which is calculated as follows:

[0067] Expression 2:

[0068] ;

[0069] Among them, in expression 2 α is the sediment concentration, d is the particle size of the entrained sand, 1 is the sediment-affected base, -0.005, 0.52, -4.2×10 -5 , -1.62, and 0.044 are all sediment influence coefficients. It can be understood that the derivation steps of Expression 2 are as follows: (1) According to the results of the classic cavitation erosion test with sediment-carrying water, the relationship between the cavitation material loss and the sediment concentration and particle size is obtained by fitting; (2) The cavitation material loss under the sediment-carrying water condition is calculated by the ratio of the cavitation material loss under the sediment-free condition to obtain the sediment correction factor. C P .

[0070] Based on stream velocity V and the maximum flow length of the cavitation zone l max , calculate the cavitation offset distance Δ l , and determine the shape of the cavitation area, including:

[0071] In the embodiment of the present invention, further, the cavitation offset distance Δ is calculated. l , and determine the shape of the cavitation area, including: according to the cavitation offset distance Δ l and the geometric outline of the cavitation zone to determine the shape of the cavitation zone.

[0072] In an embodiment of the present invention, further, Figure 7 As shown in the figure, the cavitation offset distance Δ is determined by expression 3. l , which is calculated as follows:

[0073] Expression three:

[0074] ;

[0075] Among them, in expression three V is the flow velocity, l max is the maximum flow length of the cavitation zone, and 0.022, 1, and 2 are all cavitation offset coefficients. It can be understood that the derivation steps of Expression 3 are as follows: (1) Based on the study of the influence of flow velocity on the position of the cavitation zone in the classic experiment, the relationship between the ratio of the cavitation offset distance and the maximum flow length of the cavitation zone and the flow velocity is obtained through fitting analysis; (2) Based on the assumption that different cavitation phenomena all conform to this generalized ratio relationship, the cavitation offset distance Δ can be determined by multiplying this ratio by the maximum flow length of the cavitation zone. l .

[0076] In an embodiment of the present invention, further, Figure 8 As shown, using the flow rate correction factor C V and sediment correction factor C P , the material loss in the cavitation zone is calculated by expression 4 E , to reflect the cumulative loss of material mass of the pump blades due to continuous cavitation, the amount of material loss in the cavitation area E , the calculation method is:

[0077] Expression 4:

[0078] ;

[0079] Specifically, Expression 4 can also be understood as follows:

[0080] ;

[0081] Among them, in expression 4, is the average cavitation material loss rate, ρ is the material density, A e is the area of ​​cavitation zone, and is the area of ​​cavitation zone A c equal, t 1 is the start time of the stage, t 2 is the end time of the stage, t is the cavitation time, 1.454×10 -6 , 0.34, 150, 8.8 are the material loss influence coefficients in the cavitation acceleration stage, 7.74×10 -7 , -1110, 231 is the material loss influence coefficient in the cavitation weakening stage, 3.47×10-7 is the average material loss rate in the stable stage of cavitation. It can be understood that the derivation steps of expression 4 are as follows: (1) According to the results of the standard vibration cavitation test, the expression of cavitation material loss under the condition of static water flow and no sediment is obtained by segment fitting; (2) the flow rate correction factor is C V , sediment correction factor C P Introduced into the expression in the form of a correction coefficient, the material loss in the cavitation zone under sand-carrying conditions is obtained E .

[0082] In order to better demonstrate the advantages of the method of the present invention, the calculated cavitation zone distribution characteristics are compared with the experimental cavitation zone distribution characteristics, as shown in Figure 2. Figure 2 As shown in FIG, the calculated distribution diagram of the cavitation area and erosion area of ​​the water pump blade provided by the present invention is as follows: Figure 3 As shown in the figure, it is the experimental distribution diagram of the cavitation zone of the water pump blade provided by the present invention. Analysis shows that the shape of the cavitation zone calculated by the method of the present invention is basically consistent with the experimental results and can meet the accuracy requirements of engineering calculations. Figure 4 As shown in the figure, the relationship between the amount of cavitation material loss of the water pump blade provided by the present invention and time is shown. Analysis shows that the change of the amount of cavitation material loss over time has gone through four stages: latent, acceleration, weakening and stability. t =2500min, cavitation material loss E It is about 1.02 g, which is consistent with engineering experience, indicating that the present invention can efficiently and accurately predict the amount of cavitation material loss at different cavitation development stages.

[0083] In summary, the present invention comprehensively considers the influence of water flow velocity and sediment particles on cavitation. For a given water pump, it can quickly and accurately predict the shape of the cavitation zone and the amount of material loss of its blades under different water flow velocities, sediment concentrations, and sediment particle sizes. This solves the problem that existing methods are difficult to accurately predict the shape of the cavitation zone and the amount of material loss of water pump blades under sediment conditions, and provides effective protection for cavitation protection and safe and stable operation of water pumps under sediment conditions.

[0084] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units. That is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0085] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods of each embodiment or certain portions of the embodiments.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions, characterized in that: include: Determine the relevant characteristic parameters of the shape of the cavitation zone of the water pump blade and the amount of material loss under the condition of sand entrainment, wherein the relevant characteristic parameters include at least the cavitation time t , sediment concentration α , sand particle size d , material density ρ ; In the process of spatial discretization of the object to be used for calculating the shape of the cavitation zone and the amount of material loss, a transient numerical simulation is carried out, the cavitation zone is determined by the results of the numerical simulation, and the relevant flow field parameters are obtained, the relevant flow field parameters at least including the flow velocity V , cavitation zone area A c , the maximum flow length of the cavitation zone l max ; Introducing flow rate correction factors C V and sediment correction factor C P , wherein the velocity correction factor C V and sediment correction factor C P Respectively reflect the effects of water flow velocity and sediment particles on the amount of cavitation material loss; Calculate the cavitation offset distance Δ l , and determine the shape of the cavitation area, wherein the cavitation offset distance Δ l It is used to reflect the displacement of the cavitation zone relative to the cavitation zone in the flow direction; Based on the flow rate correction factor C V and the sediment correction factor C P , calculate the material loss in the cavitation zone E , wherein the material loss in the cavitation zone is E To reflect the cumulative loss of material mass of the pump blades due to continuous cavitation; The velocity correction factor is determined by expression 1: C V , which is calculated as follows: Expression 1: ； Among them, the expression in V is the stream velocity, 1 is the velocity increment base, 1.78×10 -4 , 2.2 is the velocity increment coefficient; The sediment correction factor is determined by expression 2: C P , which is calculated as follows: Expression 2: ； Among them, in expression 2 α is the sediment concentration, d is the sediment particle size, 1 is the sediment impact base, -0.005, 0.52, -4.2×10-5, -1.62, and 0.044 are all sediment impact coefficients; The cavitation offset distance Δ is determined by expression 3: l , which is calculated as follows: Expression three: ； Among them, in expression three V is the flow velocity, l max is the maximum flow length of the cavitation zone, and 0.022, 1, and 2 are cavitation offset coefficients.

2. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 1 is characterized in that: The process of spatially discretizing the object for which the cavitation zone shape and material loss amount are to be calculated is described as follows: determining the cavitation zone and obtaining relevant flow field parameters, including: using the finite volume method to spatially discretize the object for which the cavitation zone shape and material loss amount are to be calculated.

3. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 2 is characterized in that: In the process of spatially discretizing the object for which the cavitation zone shape and material loss calculation is to be carried out, a transient numerical simulation is carried out, the cavitation zone is determined through the results of the numerical simulation, and relevant flow field parameters are obtained, which also includes: Select a computational model to carry out transient numerical simulation and obtain numerical simulation results; Based on the numerical simulation results, the cavitation region is determined, and the relevant flow field parameters are obtained therefrom.

4. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 3 is characterized in that: The selected calculation models include the ZGB cavitation model and the SSTk-ω turbulence model.

5. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 1 is characterized in that: In the process of spatially discretizing the object to be used for calculating the shape of the cavitation zone and the amount of material loss, the cavitation zone is determined and the relevant flow field parameters are obtained. The relevant flow field parameters include at least the flow velocity. V , cavitation zone area A c , the maximum flow length of the cavitation zone l max Also included: The stream velocity V The magnitude is equal to the average axial velocity of the blade inlet edge, and its direction is perpendicular to the axial plane of the blade inlet edge.

6. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 1 is characterized in that: The calculated cavitation offset distance Δ l , and determining the shape of the cavitation zone, including: According to the cavitation offset distance Δ l and the geometric outline of the cavitation zone to determine the shape of the cavitation zone.

7. The method for calculating the shape of the cavitation zone and the amount of material loss of a water pump blade under sand-carrying conditions according to claim 1 is characterized in that: According to Expression 4, the material loss E in the cavitation zone is calculated as follows: Expression 4: ； Among them, in expression 4, is the average cavitation material loss rate, ρ is the material density, A e is the area of ​​cavitation zone, and is the area of ​​cavitation zone A c equal, t 1 is the start time of the stage, t 2 is the end time of the stage, t is the cavitation time, 1.454×10 -6 , 0.34, 150, 8.8 are the material loss influence coefficients in the cavitation acceleration stage, 7.74×10 -7 , -1110, 231 is the material loss influence coefficient in the cavitation weakening stage, 3.47×10 -7 is the average material loss rate in the stable stage of cavitation.

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