Simulation prediction method for hydraulic noise of shield pump

Abstract

The invention relates to a shield pump hydraulic noise simulation prediction method comprising the following steps: carrying out CFD flow field solution analysis on a shield pump model to obtain a steady state flow field value; obtaining the position coordinates of each monitoring point according to the correlation between each monitoring point and the shape and size parameters of the baffle tongue; the obtained steady-state flow field value serves as an initial value, pressure pulsation transient unsteady calculation is conducted on a shield pump model, the pressure pulsation characteristic number # imgabs0 # of a monitoring point group P is obtained, the monitoring point group is selected near a baffle tongue, the pressure pulsation characteristic number # imgabs1 # of the monitoring point group P is more representative, and the pressure pulsation characteristic number # imgabs0 # of the monitoring point group P is more accurate. And the pressure pulsation characteristic number # imgabs2 # of the monitoring point group P is obtained through pressure pulsation transient unsteady calculation so as to represent the hydraulic noise caused by the pressure pulsation of the baffle tongue, so that a product design scheme with low hydraulic noise can be screened out, the hydraulic noise of the shield pump can be predicted without making a sample machine, the number of times of repeated sample making of the product is reduced, and the production efficiency is improved. The product research and development period is shortened, and the product research and development cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of shielded pump design, and in particular to a simulation prediction method for hydraulic noise of a shielded pump. Background Art

[0002] At present, the market has higher and higher requirements for water pump products, especially the noise performance of water pumps used in indoor scenes, which is directly related to the user experience and sensory comfort. Generally, the designed water pump needs to be tested for noise after the prototype is made to evaluate the noise performance of the water pump prototype. If the noise performance of the water pump prototype does not meet the requirements, the design plan needs to be adjusted repeatedly, and the proofing needs to be repeated, which increases the research and development cost of the water pump and prolongs the research and development cycle of the water pump. Therefore, in the design stage of the water pump, it becomes very necessary to simulate and predict the noise of the shielded pump, so as to evaluate and screen out low-noise and high-performance product design plans.

[0003] In the prior art, the conventional noise simulation method is to calculate the noise of the entire water pump. The noise of the entire water pump includes hydraulic noise, motor noise and structural noise, etc. The steps are cumbersome, the process is complicated, and the simulation time period is long. In addition, the above conventional noise simulation method is not suitable for shielded pumps, because the motor and hydraulic components of the shielded pump are packaged as one body, the amplitude of the motor noise is on the same order of magnitude as the hydraulic noise, and the motor noise is more often dominant. The above conventional noise simulation method cannot separate the separate hydraulic noise. Therefore, the conventional noise simulation method cannot separately evaluate the hydraulic noise of the product design scheme during the design stage of the shielded pump.

[0004] Therefore, there is an urgent need for a simulation prediction method for shielding pump hydraulic noise to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a simulation prediction method for shielding pump hydraulic noise to at least solve one of the above problems.

[0006] To achieve the above object, the present invention provides a simulation prediction method for shielding pump hydraulic noise, comprising the following steps:

[0007] Step S1: CFD steady-state flow field solution: simplify the designed canned pump model, extract the fluid domain, perform meshing, set boundary conditions, and then perform CFD flow field solution analysis on the simplified canned pump model to obtain steady-state flow field values;

[0008] Step S2: Select a monitoring point group P: The monitoring point group P refers to a set of n monitoring points {P1, P2, P3, ..., P i , ... P n}, according to the association between each monitoring point and the shape and size parameters of the tongue, the position coordinates of each monitoring point are obtained;

[0009] Step S3: Pressure pulsation transient unsteady calculation: Take the steady-state flow field value obtained in step S1 as the initial value, perform pressure pulsation transient unsteady calculation on the designed shielded pump model, and obtain the pressure pulsation characteristic number of the monitoring point group P

[0010]

[0011] In the formula, is the monitoring point P i The average sound pressure caused by the pressure pulsation;

[0012] The pressure pulsation characteristic number of the monitoring point group P The size of the hydraulic noise of the designed shielded pump model is used to predict the level of the hydraulic noise.

[0013] Furthermore, the selected monitoring point group P includes the selection of first-category monitoring points, second-category monitoring points and third-category monitoring points, and the first-category monitoring points, second-category monitoring points and third-category monitoring points are selected along the contour of the partition tongue.

[0014] Furthermore, the selection of the first type of monitoring points includes the following steps:

[0015] Construct a first auxiliary ray set: the first auxiliary ray set is a set of e first rays, each of which is obtained by rotating the reference ray OA1 around the impeller rotation center O along the first direction, and the reference ray OA1 is a line connecting the impeller rotation center O and the intersection point A1 of the first partition tongue arc and the second partition tongue arc of the partition tongue;

[0016] Select the first type of monitoring points: the number of the first type of monitoring points is e, and the intersection points of each first ray in the first auxiliary ray set and the first tongue arc of the tongue are A1, A2, A3, ..., A i , ... A e , 1≤i≤e, the intersection points of each first ray in the first auxiliary ray set with the impeller contour circle are B1, B2, B3, ..., B i , ... B e , two points A corresponding to the same first ray i and B i Connect to form line segment A i B i , the first type of monitoring point is line segment A i B i The equal division point.

[0017] Preferably, the first type of monitoring point P i For line segment Ai B i The midpoint of .

[0018] Furthermore, the second-category monitoring points include special second-category monitoring points and ordinary second-category monitoring points, and the selection of the second-category monitoring points includes the following steps:

[0019] Select special second-class monitoring points: The number of special second-class monitoring points is one, and the intersection of the second and third arcs of the tongue is A. e+1 , past point A e+1 A special vertical line A is used as the outlet diffusion curve of the pressure chamber e+1 B e+1 , B e+1 A is a special vertical line e+1 B e+1 The foot of the vertical, special second-class monitoring point P e+1 A is a special vertical line e+1 B e+1 The equal points of

[0020] Select ordinary second-class monitoring points: The number of ordinary second-class monitoring points is e-1. The intersection points of each first ray in the first auxiliary ray set and the third tongue arc of the tongue are defined as reference points, that is, the reference points are A e+2 , A e+3 , A e+4 , ..., A i , ... A 2e , e+2≤i≤2e, and make the reference vertical line A of the outlet diffusion curve of the pressurized water chamber through each reference point respectively i B i , B i A is the reference vertical line i B i The foot of the vertical, ordinary second-class monitoring point P i A is the reference vertical line i B i The equal division point.

[0021] Furthermore, the selection of the third type of monitoring points includes the following steps:

[0022] Construct a second auxiliary ray set: the second auxiliary ray set is a set consisting of n-2e second rays, each of which is obtained by rotating the reference ray OA1 around the impeller rotation center O along the second direction, and the first direction is opposite to the second direction;

[0023] Select the third type of monitoring points: The number of the third type of monitoring points is n-2e, and the intersection points of each second ray in the second auxiliary ray set and the base circle are the third type of monitoring points, that is, P 2e+1 , P 2e+2 , P 2e+3 , ..., Pi , ... P n , 2e+1≤i≤n.

[0024] Furthermore, the ray area formed by each first ray in the first auxiliary ray set and each second ray in the second auxiliary ray set is less than or equal to the monitoring limit area, and the monitoring limit area refers to the area formed by the first limit ray OJ1 and the second limit ray OJ2, and the first limit ray OJ1 and the second limit ray OJ2 are both tangents of the limit circle, and the limit circle is formed by the line segment A1A e+1 The midpoint C is the center of the circle, and the radius r = 1.5*CB e+1 circle.

[0025] Furthermore, the angle between two adjacent first rays in the first auxiliary ray set is 3°-10°.

[0026] Furthermore, along the first direction, each angle formed between two adjacent first rays in the first auxiliary ray set gradually increases.

[0027] Further, step S3 includes the following steps:

[0028] Step S31: using the steady-state flow field value obtained in step S1 as the initial value, performing transient unsteady calculation of pressure pulsation on the designed canned motor pump model, and obtaining the pressure pulsation value of each monitoring point in the monitoring point group P at different times;

[0029] Step S32: Perform Fourier transform on the pressure pulsation values ​​at different times of each monitoring point in the monitoring point group P to obtain the pressure pulsation values ​​at different frequencies of each monitoring point in the monitoring point group P;

[0030] Step S33: obtaining the sound pressure value caused by the pressure pulsation at different frequencies at each monitoring point in the monitoring point group P according to the pressure pulsation value at different frequencies at each monitoring point in the monitoring point group P;

[0031] Step S34: calculating the average value of the sound pressure value caused by pressure pulsation at each monitoring point in the monitoring point group P;

[0032] Step S35: Calculate the pressure pulsation characteristic number of the monitoring point group P

[0033] The beneficial effects of the present invention are:

[0034] The simulation prediction method of the canned motor pump hydraulic noise provided by the present invention comprises the following steps:

[0035] Step S1: CFD steady-state flow field solution: simplify the designed canned pump model, extract the fluid domain, perform meshing, set boundary conditions, and then perform CFD flow field solution analysis on the simplified canned pump model to obtain steady-state flow field values;

[0036] Step S2: Select a monitoring point group P: The monitoring point group P refers to a set of n monitoring points {P1, P2, P3, ..., P i , ... P n}, according to the association between each monitoring point and the shape and size parameters of the partition tongue (2), the position coordinates of each monitoring point are obtained;

[0037] Step S3: Pressure pulsation transient unsteady calculation: Take the steady-state flow field value obtained in step S1 as the initial value, perform pressure pulsation transient unsteady calculation on the designed shielded pump model, and obtain the pressure pulsation characteristic number of the monitoring point group P

[0038]

[0039] In the formula, is the monitoring point P i The average sound pressure caused by the pressure pulsation;

[0040] The pressure pulsation characteristic number of the monitoring point group P The size of the hydraulic noise of the designed shielded pump model is used to predict the level of the hydraulic noise.

[0041] A group of monitoring points is selected near the tongue so that the pressure pulsation characteristic number of the monitoring point group P is The pressure pulsation characteristic number of the monitoring point group P is obtained by transient unsteady calculation of pressure pulsation. This can characterize the size of the hydraulic noise caused by the pressure pulsation of the diaphragm, and can screen out product design solutions with low hydraulic noise. The hydraulic noise of the shielded pump can be predicted without making a prototype, reducing the number of repeated product proofing, shortening the product development cycle, and reducing product development costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of a simulation prediction method for hydraulic noise of a canned motor pump provided by an embodiment of the present invention;

[0043] Figure 2 The structure of the canned pump provided by the embodiment of the present invention is shown in FIG. Figure 1 ;

[0044] Figure 3 The structure of the canned pump provided by the embodiment of the present invention is shown in FIG. Figure 2 ;

[0045] Figure 4 yes Figure 3 A partial enlarged view of point D in the middle;

[0046] Figure 5 It is a distribution diagram of the monitoring point group when e=3, n=8, and the angle between two adjacent first rays is 5°.

[0047] In the figure:

[0048] 100, monitoring plane; 200, impeller contour circle; 300, base circle; 400, limit circle;

[0049] 1. Water pressure chamber; 2. Divider tongue;

[0050] 11. First end face; 12. Second end face; 13. Exit diffusion section curve; 21. First partition tongue arc; 22. Second partition tongue arc; 23. Third partition tongue arc. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It is also necessary to explain that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all.

[0052] Some directional words are defined in the present invention. Unless otherwise specified, the directional words used, such as "up", "down", "left", "right", "inside" and "outside", are used to facilitate understanding and therefore do not constitute a limitation on the scope of protection of the present invention.

[0053] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0054] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] like Figure 1 As shown, this embodiment provides a simulation prediction method for the hydraulic noise of a shielded pump, which can be used in the design stage of the shielded pump to perform a qualitative evaluation of the hydraulic noise of different design schemes of the shielded pump, so as to screen out the design scheme with low hydraulic noise. The hydraulic noise of the shielded pump can be predicted without making a prototype, thereby reducing the number of repeated product proofing, shortening the product development cycle, and reducing product development costs.

[0056] The present embodiment provides a method for simulating and predicting hydraulic noise of a shielded pump, comprising the following steps:

[0057] Step S1: CFD (Computational Fluid Dynamics) steady-state flow field solution: simplify the designed canned pump model, extract the fluid domain, perform meshing, set boundary conditions, and then perform CFD flow field solution analysis on the simplified canned pump model to obtain steady-state flow field values;

[0058] Step S2: Select a monitoring point group P: The monitoring point group P refers to a set of n monitoring points {P1, P2, P3, ..., P i , ... P n}, 1≤i≤n, according to the association between each monitoring point and the shape and size parameters of the partition tongue 2, the position coordinates of each monitoring point are obtained;

[0059] Step S3: Pressure pulsation transient unsteady calculation: Take the steady-state flow field value obtained in step S1 as the initial value, perform pressure pulsation transient unsteady calculation on the designed shielded pump model, and obtain the pressure pulsation characteristic number of the monitoring point group P

[0060]

[0061] In the formula, is the monitoring point P i The average sound pressure caused by the pressure pulsation;

[0062] The pressure pulsation characteristic number of the monitoring point group P The size of the hydraulic noise of the designed shielded pump model is used to predict the level of the hydraulic noise.

[0063] Since the hydraulic noise of the canned motor pump is mainly caused by the static-dynamic interference between the volute and the impeller, especially the baffle 2 located in the pressure chamber 1 is an important factor affecting the pressure pulsation of the internal flow field of the canned motor pump. Therefore, a monitoring point group P is selected near the baffle 2 so that the pressure pulsation characteristic number of the monitoring point group P is More representative.

[0064] The pressure pulsation characteristic number of the monitoring point group P is obtained by transient unsteady calculation of pressure pulsation The hydraulic noise caused by the pressure pulsation formed at n monitoring points near the partition tongue 2 is integrated to characterize the size of the hydraulic noise caused by the pressure pulsation of the partition tongue 2. Product design solutions with low hydraulic noise can be screened out. The hydraulic noise of the shielded pump can be predicted without making a prototype, reducing the number of repeated product proofing, shortening the product development cycle, and reducing product development costs.

[0065] According to the design parameters and design objectives, combined with the design points, the main geometric parameters of the water pressure chamber 1 are obtained, and then several design schemes of the shielded pump are obtained. Then, the simulation prediction method of the hydraulic noise of the shielded pump provided in this embodiment is used to simulate the hydraulic noise of the above-mentioned several design schemes to screen out the design scheme of the shielded pump with low hydraulic noise.

[0066] In step S1, model simplification, fluid domain extraction, mesh division and boundary condition setting are all related to the design scheme of the shielded pump. The specific setting parameters of the above simulation may be slightly different for different design schemes. Therefore, the specific parameters of model simplification, fluid domain extraction, mesh division and boundary condition setting are not described here.

[0067] In step S1, after meshing the canned motor pump model, it is necessary to perform a quality check on the meshed components to ensure that the mesh quality meets the calculation requirements.

[0068] Specifically, for fluid grids, a grid quality greater than 0.3 can meet the computational requirements.

[0069] In step S1 , the boundary conditions include inlet mass, inlet flow, outlet pressure, interface, wall, etc.

[0070] In step S1, a no-slip wall is selected as the wall.

[0071] In step S1, during the CFD flow field solution analysis, it is necessary to monitor the changes in the convergence residual in order to smoothly obtain the solution value. The CFD simulation flow field analysis calculation is performed iteratively. The convergence residual is the difference between the calculation result of the nth step and the calculation result of the n-1th step. When the convergence residual is lower than the preset value, it is determined that the calculation result of the CFD simulation flow field analysis has converged. When the calculation result of the CFD simulation flow field analysis converges, the CFD simulation flow field analysis ends.

[0072] When the calculation results of CFD simulation flow field analysis do not converge, the simulation parameters need to be readjusted before performing simulation calculations.

[0073] In step S1, the steady-state flow field values ​​include velocity distribution, pressure distribution, vortex distribution, etc. in the flow field, which is a prerequisite for implementing the transient unsteady calculation of pressure pulsation in step S3.

[0074] In this embodiment, n monitoring points are numbered, P1, P2, P3, ..., P i , ... P n , 1≤i≤n, is to facilitate the distinction of the n monitoring points in the monitoring point group P. There is no order of precedence or priority among the n monitoring points.

[0075] like Figure 2 As shown, the n monitoring points included in the monitoring point group P are all located in the monitoring plane 100, and the monitoring plane 100 is parallel to the first end face 11 and the second end face 12 of the pressure chamber 1, respectively, and the distance from the monitoring plane 100 to the first end face 11 is equal to the distance from the monitoring plane 100 to the second end face 12. The reason for selecting the above n monitoring points on the monitoring plane 100 is that the pressure chamber 1 is most completely presented on the monitoring plane 100. In addition, the monitoring plane 100 is both a symmetry plane and a mid-axis plane. The monitoring plane 100 is not affected by the cross-sectional shape of the pressure chamber 1, and is least affected by the wall of the pressure chamber 1.

[0076] In order to facilitate the subsequent description of the selection of the monitoring point group P, the partial structure of the canned motor pump is first described.

[0077] like Figure 3-Figure 5 As shown, the tongue 2 includes a first tongue arc 21, a second tongue arc 22 and a third tongue arc 23. The first tongue arc 21 and the second tongue arc 22 intersect at point A1, and the second tongue arc 22 and the third tongue arc 23 intersect at point A2. e+1 , line segment A1A e+1 The midpoint of is point C.

[0078] like Figure 3 As shown, the impeller contour circle 200 is a circle with the impeller rotation center O as the center and coincident with the contour circle where the impeller outer diameter is located, and the base circle 300 is a circle with the impeller rotation center O as the center and the line segment OC as the radius.

[0079] like Figure 3 and Figure 4 As shown, the selected monitoring point group P includes the selection of the first type of monitoring points, the second type of monitoring points and the third type of monitoring points, and the first type of monitoring points, the second type of monitoring points and the third type of monitoring points are selected along the contour of the partition tongue 2. Since the hydraulic noise of the shielded pump is mainly caused by the dynamic and static interference between the volute and the impeller, especially the partition tongue 2 is an important factor affecting the pressure pulsation of the internal flow field of the shielded pump, therefore, the monitoring point group P is selected near the partition tongue 2, so that the simulation result of the hydraulic noise of the shielded pump obtained by simulation prediction is more accurate.

[0080] Furthermore, the selection of the first type of monitoring points includes the following steps:

[0081] Construct a first auxiliary ray set: the first auxiliary ray set is a set of e first rays, each of which is obtained by rotating the reference ray OA1 around the impeller rotation center O along the first direction, and the reference ray OA1 is a line connecting the impeller rotation center O and the intersection point A1 of the first partition tongue arc 21 and the second partition tongue arc 22 of the partition tongue 2;

[0082] Select the first type of monitoring points: the number of the first type of monitoring points is e, and the intersection points of each first ray in the first auxiliary ray set and the first tongue arc 21 of the tongue 2 are A1, A2, A3, ..., A i , ... A e , 1≤i≤e, the intersection points of each first ray in the first auxiliary ray set with the impeller contour circle 200 are B1, B2, B3, ..., B i , ... B e , two points A corresponding to the same first ray i and B i Connect to form line segment A i B i , the first type of monitoring point is line segment A i B i The equal division point.

[0083] Preferably, the first type of monitoring point P i For line segment A i B i The midpoint of .

[0084] Furthermore, the second-category monitoring points include special second-category monitoring points and ordinary second-category monitoring points, and the selection of the second-category monitoring points includes the following steps:

[0085] Select special second-class monitoring points: The number of special second-class monitoring points is one, and the intersection point of the second partition tongue arc 22 and the third partition tongue arc 23 of the partition tongue 2 is A e+1 , past point A e+1A special vertical line A is formed as the outlet diffusion curve 13 of the pressure chamber 1 e+1 B e+1 , B e+1 A is a special vertical line e+1 B e+1 The foot of the vertical, special second-class monitoring point P e+1 A is a special vertical line e+1 B e+1 The equal points of

[0086] Select ordinary second-class monitoring points: The number of ordinary second-class monitoring points is e-1. The intersection points of each first ray in the first auxiliary ray set and the third tongue arc 23 of the tongue 2 are defined as reference points, that is, the reference points are A e+2 , A e+3 , A e+4 , ..., A i , ... A 2e , e+2≤i≤2e, and make a reference vertical line A of the outlet diffusion curve 13 of the pressure chamber 1 through each reference point. i B i , B i A is the reference vertical line i B i The foot of the vertical, ordinary second-class monitoring point P i A is the reference vertical line i B i The equal division point.

[0087] Preferably, the special second type monitoring point P e+1 A is a special vertical line e+1 B e+1 The midpoint of the ordinary second-class monitoring point P i A is the reference vertical line i B i The midpoint of .

[0088] Furthermore, the selection of the third type of monitoring points includes the following steps:

[0089] Construct a second auxiliary ray set: the second auxiliary ray set is a set consisting of n-2e second rays, each of which is obtained by rotating the reference ray OA1 around the impeller rotation center O along the second direction, and the first direction is opposite to the second direction;

[0090] Select the third type of monitoring points: The number of the third type of monitoring points is n-2e, and the intersection points of each second ray in the second auxiliary ray set and the base circle 300 are the third type of monitoring points, that is, P 2e+1 , P 2e+2 , P 2e+3 , ..., P i , ... P n , 2e+1≤i≤n.

[0091] Furthermore, the first direction refers to a direction of rotation from the second tongue arc 22 to the first tongue arc 21 , and the second direction is opposite to the first direction.

[0092] In this embodiment, Figure 3 As shown, the first direction is counterclockwise and the second direction is clockwise.

[0093] Furthermore, the ray area formed by each first ray in the first auxiliary ray set and each second ray in the second auxiliary ray set is less than or equal to the monitoring limit area, and the monitoring limit area refers to the area formed by the first limit ray OJ1 and the second limit ray OJ2, and the first limit ray OJ1 and the second limit ray OJ2 are both tangents of the limit circle, and the limit circle is formed by the line segment A1A e+1 The midpoint C is the center of the circle, and the radius r = 1.5*CB e+1 The monitoring boundary area can completely cover the outline of the partition tongue 2. Selecting monitoring points from the above monitoring boundary area can prevent the selection of invalid monitoring points, so as to ensure that the qualitative evaluation of the hydraulic noise of the shielded pump is more accurate.

[0094] Furthermore, the angle between two adjacent first rays in the first auxiliary ray set is 3°-10°.

[0095] Furthermore, the angle between two adjacent second rays in the second auxiliary ray set is 3°-10°.

[0096] Furthermore, the angle between adjacent first rays and second rays is 3°-10°.

[0097] Optionally, along the first direction, each angle formed between two adjacent first rays in the first auxiliary ray set gradually increases, and each angle formed between two adjacent second rays in the second auxiliary ray set gradually decreases. Such a selection mechanism will result in different densities of monitoring points near different positions of the tongue 2, because the hydraulic noise near the second tongue arc 22 is greater, and the more monitoring points are selected near the second tongue arc 22, the closer the hydraulic noise of the shielded pump obtained by simulation prediction is to the real hydraulic noise.

[0098] Furthermore, for a large-sized partition tongue 2, a larger angle may be appropriately selected to prevent the monitoring points from being too dense; for a small-sized partition tongue 2, a smaller angle may be appropriately selected to prevent the monitoring points from being too sparse.

[0099] In order to facilitate understanding of the method for selecting the monitoring point group P, this embodiment is described by taking the selection of eight monitoring points as an example.

[0100] like Figure 5As shown, when eight monitoring points are selected, that is, n=8, according to the size parameters of the partition tongue 2, three first-type monitoring points, three second-type monitoring points, and two third-type monitoring points can be selected, that is, e=3, n-2e=2, and the monitoring point group P={P1, P2, P3, P4, P5, P6, P7, P8}.

[0101] Among them, monitoring points P1, P2 and P3 are first-type monitoring points, and the angles formed between two adjacent first rays in the first auxiliary ray set are the same and are all 5°, that is, the first auxiliary ray set includes three first rays, and the three first rays are OA1, OA2 and OA3, respectively. The first ray OA1 is obtained by rotating the reference ray OA1 by 0° along the first direction around the impeller rotation center O, the first ray OA2 is obtained by rotating the reference ray OA1 by 5° along the first direction around the impeller rotation center O, and the first ray OA3 is obtained by rotating the reference ray OA1 by 10° along the first direction around the impeller rotation center O. The first-type monitoring point P1 is the midpoint of the line segment A1B1, the first-type monitoring point P2 is the midpoint of the line segment A2B2, and the first-type monitoring point P3 is the midpoint of the line segment A3B3.

[0102] Monitoring points P4, P5 and P6 are second-class monitoring points, monitoring point P4 is a special second-class monitoring point, monitoring points P5 and P6 are ordinary second-class monitoring points, the intersection of the second partition tongue arc 22 and the third partition tongue arc 23 of the partition tongue 2 is A4, a special vertical line A4B4 of the outlet diffusion section curve 13 is made through point A4, B4 is the foot of the special vertical line A4B4, the special second-class monitoring point P4 is the midpoint of the special vertical line A4B4, the intersection of the first ray OA2 and the third partition tongue arc 23 of the partition tongue 2 is The point is the reference point A5, and a reference vertical line A5B5 of the outlet diffusion section curve 13 is made through point A5. B5 is the foot of the reference vertical line A5B5. The ordinary second-class monitoring point P5 is the midpoint of the reference vertical line A5B5. The intersection of the first ray OA3 and the third tongue arc 23 of the tongue 2 is the reference point A6. A reference vertical line A6B6 of the outlet diffusion section curve 13 is made through point A6. B6 is the foot of the reference vertical line A6B6. The ordinary second-class monitoring point P6 is the midpoint of the reference vertical line A6B6.

[0103] Monitoring points P7 and P8 are third-category monitoring points. The angles formed between two adjacent second rays in the second auxiliary ray set are the same and are all 5°, that is, the second auxiliary ray set includes two second rays, and the two second rays are obtained by rotating the reference ray OA1 by 5° and 10° along the second direction around the impeller rotation center O, respectively. The intersection of the two second rays and the base circle 300 is the monitoring points P7 and P8, that is, the two first rays are OP7 and OP8, respectively.

[0104] In step S2, after the monitoring point group P is selected, the position coordinates of each monitoring point can be obtained through the measurement function of the simulation software.

[0105] Since the position coordinates of each monitoring point in the monitoring point group P are parameter-associated with the shape and size parameters of the partition tongue 2, the shape and size parameters of the partition tongue 2 in the water pressure chamber 1 of different shielded pumps are different. Therefore, the position coordinates of each monitoring point in the monitoring point group P in different shielded pumps are also different.

[0106] Further, step S3 includes the following steps:

[0107] Step S31: using the steady-state flow field value obtained in step S1 as the initial value, performing transient unsteady calculation of pressure pulsation on the designed canned motor pump model, and obtaining the pressure pulsation value of each monitoring point in the monitoring point group P at different times;

[0108] Step S32: Perform Fourier transform on the pressure pulsation values ​​at different times of each monitoring point in the monitoring point group P to obtain the pressure pulsation values ​​at different frequencies of each monitoring point in the monitoring point group P;

[0109] Step S33: obtaining the sound pressure value caused by the pressure pulsation at different frequencies at each monitoring point in the monitoring point group P according to the pressure pulsation value at different frequencies at each monitoring point in the monitoring point group P;

[0110] Step S34: calculating the average value of the sound pressure value caused by pressure pulsation at each monitoring point in the monitoring point group P;

[0111] Step S35: Calculate the pressure pulsation characteristic number of the monitoring point group P

[0112] In step S31, when performing pressure pulsation transient unsteady calculation on the designed canned pump model, it is necessary to determine the calculation parameters of the pressure pulsation transient calculation, and the calculation parameters are determined according to the design parameters of the canned pump and the Nyquist sampling theorem.

[0113] Furthermore, the calculation parameters include boundary conditions, sampling steps and sampling time, the boundary conditions are determined according to the design parameters of the canned motor pump, and the sampling steps and sampling time are determined according to the Nyquist sampling theorem.

[0114] In step S31, the pressure pulsation values ​​of the last four or eight cycles of each monitoring point are selected as effective values ​​for pressure pulsation characteristic number calculation. Because the flow field stabilizes in the last four or eight cycles, the pressure pulsation value obtained can be sampled and processed as an effective value.

[0115] In step S32, Fourier transform converts different time domain values ​​of pressure pulsation of each monitoring point in the monitoring point group P into different frequency domain values, so as to obtain

[0116] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A simulation prediction method for hydraulic noise of a canned motor pump, characterized in that: The steps include: Step S1: CFD steady-state flow field solution: simplify the designed canned pump model, extract the fluid domain, perform meshing, set boundary conditions, and then perform CFD flow field solution analysis on the simplified canned pump model to obtain steady-state flow field values; Step S2: Select a monitoring point group P: The monitoring point group P refers to a set of n monitoring points {P1, P2, P3, ..., P i , ... P n }, according to the association between each monitoring point and the shape and size parameters of the partition tongue (2), the position coordinates of each monitoring point are obtained; Step S3: Pressure pulsation transient unsteady calculation: Take the steady-state flow field value obtained in step S1 as the initial value, perform pressure pulsation transient unsteady calculation on the designed shielded pump model, and obtain the pressure pulsation characteristic number of the monitoring point group P In the formula, is the monitoring point P i The average sound pressure caused by the pressure pulsation; The pressure pulsation characteristic number of the monitoring point group P The size of the hydraulic noise of the designed shielded pump model is used to predict the level of hydraulic noise.

2. The simulation prediction method of canned motor pump hydraulic noise according to claim 1 is characterized in that: The monitoring point group P includes the selection of first-category monitoring points, second-category monitoring points and third-category monitoring points, and the first-category monitoring points, second-category monitoring points and third-category monitoring points are selected along the contour of the partition tongue.

3. The simulation prediction method of canned motor pump hydraulic noise according to claim 2 is characterized in that: The selection of the first type of monitoring points includes the following steps: Constructing a first auxiliary ray set: the first auxiliary ray set is a set consisting of e first rays, each of which is obtained by rotating a reference ray OA1 around the impeller rotation center O along a first direction, and the reference ray OA1 is a line connecting the impeller rotation center O and the intersection point A1 of the first partition tongue arc (21) and the second partition tongue arc (22) of the partition tongue (2); Select the first type of monitoring points: the number of the first type of monitoring points is e, and the intersection points of each first ray in the first auxiliary ray set and the first tongue arc (21) of the tongue (2) are A1, A2, A3, ..., A i , ... A e , 1≤i≤e, the intersection points of each first ray in the first auxiliary ray set with the impeller contour circle (200) are B1, B2, B3, ..., B i , ... B e , two points A corresponding to the same first ray i and B i Connect to form line segment A i B i , the first type of monitoring point is line segment A i B i The equal division point.

4. The simulation prediction method of canned motor pump hydraulic noise according to claim 3 is characterized in that: The first type of monitoring point P i For line segment A i B i The midpoint of .

5. The simulation prediction method of canned motor pump hydraulic noise according to claim 3 is characterized in that: The second-class monitoring points include special second-class monitoring points and ordinary second-class monitoring points. The selection of second-class monitoring points includes the following steps: Select a special second-class monitoring point: the number of special second-class monitoring points is one, and the intersection point of the second partition tongue arc (22) and the third partition tongue arc (23) of the partition tongue (2) is A. e+1 , past point A e+1 A special vertical line A is formed as the outlet diffusion curve (13) of the pressure chamber (1). e+1 B e+1 , B e+1 A is a special vertical line e+1 B e+1 The foot of the vertical, special second-class monitoring point P e+1 A is a special vertical line e+1 B e+1 The equal points of Select ordinary second-class monitoring points: The number of ordinary second-class monitoring points is e-1. The intersection points of each first ray in the first auxiliary ray set and the third tongue arc (23) of the tongue (2) are defined as reference points, that is, the reference points are A e+2 , A e+3 , A e+4 , ..., A i , ... A 2e , e+2≤i≤2e, and a reference vertical line A of the outlet diffusion curve (13) of the pressure chamber (1) is drawn through each reference point. i B i , B i A is the reference vertical line i B i The foot of the vertical, ordinary second-class monitoring point P i A is the reference vertical line i B i The equal division point.

6. The simulation prediction method of canned motor pump hydraulic noise according to claim 5 is characterized in that: The selection of the third type of monitoring points includes the following steps: Construct a second auxiliary ray set: the second auxiliary ray set is a set consisting of n-2e second rays, each of which is obtained by rotating the reference ray OA1 around the impeller rotation center O along the second direction, and the first direction is opposite to the second direction; Select the third type of monitoring points: The number of the third type of monitoring points is n-2e, and the intersection of each second ray in the second auxiliary ray set and the base circle (300) is the third type of monitoring point, that is, P 2e+1 , P 2e+2 , P 2e+3 , ..., P i , ... P n , 2e+1≤i≤n.

7. The simulation prediction method of canned motor pump hydraulic noise according to claim 6 is characterized in that: The ray area formed by each first ray in the first auxiliary ray set and each second ray in the second auxiliary ray set is less than or equal to the monitoring boundary area. The monitoring boundary area refers to the area formed by the first boundary ray OJ1 and the second boundary ray OJ2. The first boundary ray OJ1 and the second boundary ray OJ2 are both tangents of the boundary circle. The boundary circle is the line segment A1A e+1 The midpoint C is the center of the circle, and the radius r = 1.5*CB e+1 circle.

8. The simulation prediction method for canned motor pump hydraulic noise according to claim 3 is characterized in that: The angle between two adjacent first rays in the first auxiliary ray set is 3°-10°.

9. The simulation prediction method of canned motor pump hydraulic noise according to claim 8 is characterized in that: Along the first direction, each angle formed between two adjacent first rays in the first auxiliary ray set gradually increases.

10. The simulation prediction method for hydraulic noise of a canned motor pump according to any one of claims 1 to 9, characterized in that: Step S3 includes the following steps: Step S31: using the steady-state flow field value obtained in step S1 as the initial value, performing transient unsteady calculation of pressure pulsation on the designed canned motor pump model, and obtaining the pressure pulsation value of each monitoring point in the monitoring point group P at different times; Step S32: Perform Fourier transform on the pressure pulsation values ​​at different times of each monitoring point in the monitoring point group P to obtain the pressure pulsation values ​​at different frequencies of each monitoring point in the monitoring point group P; Step S33: obtaining the sound pressure value caused by the pressure pulsation at different frequencies at each monitoring point in the monitoring point group P according to the pressure pulsation value at different frequencies at each monitoring point in the monitoring point group P; Step S34: calculating the average value of the sound pressure value caused by pressure pulsation at each monitoring point in the monitoring point group P; Step S35: Calculate the pressure pulsation characteristic number of the monitoring point group P

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