Optimization design method for streamlined counter-guide vanes of multistage centrifugal pump

Abstract

The application discloses a multi-stage centrifugal pump streamline reverse guide vane optimization design method, which optimizes the reverse guide vane structure without changing the original multi-stage centrifugal pump radial guide vane blade number and the overall size of the guide vane structure. The application can ensure weakening of flow separation in the reverse guide vane structure of the multi-stage centrifugal pump, reduce the blade profile loss and secondary flow loss of the reverse guide vane area, and improve the overall efficiency of the multi-stage centrifugal pump.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radial guide vanes of multistage centrifugal pumps, and relates to a streamlined reverse vane optimization design method for a multistage centrifugal pump. BACKGROUND

[0002] The multistage centrifugal pump is widely used in the fields of agriculture, mining, petroleum chemical industry, and power due to high lift and small size, and improving the performance of the multistage centrifugal pump is of great significance in energy saving and emission reduction and technical development. The radial guide vane is an important flow part of the multistage centrifugal pump, which is composed of a forward vane and a reverse vane, is responsible for collecting the high-speed liquid flow out of the upper-stage impeller, reduces the speed, eliminates the liquid rotating part, converts the kinetic energy of the liquid into pressure energy, and makes the liquid enter the next-stage impeller at a certain speed and circulation.

[0003] The performance of the guide vane has an important influence on the performance of the multistage pump, but the internal flow field structure of the guide vane is complex, the hydraulic loss is large, and the influence on the hydraulic efficiency of the pump is obvious. Due to the influence of the centrifugal force and the Coriolis force, the flow at the outlet of the centrifugal pump impeller is very uneven, generally showing a "jet wake" flow structure. This uneven flow is easy to cause local flow separation to form vortex and other secondary flows after entering the diffusion type flow passage of the reverse vane of the radial guide vane, causing great resistance to fluid movement, increasing internal consumption, and thus reducing the efficiency of the multistage pump, especially when deviating from the design condition. Therefore, the key of the optimization of the reverse vane is to reduce the vortex at the guide vane, so that the overall speed and pressure distribution tend to be uniform, thereby improving the overall efficiency of the multistage pump. SUMMARY

[0004] The purpose of the application is to provide a streamlined reverse vane optimization design method for a multistage centrifugal pump, which can ensure that the flow separation in the reverse vane structure of the multistage centrifugal pump is weakened, the profile loss and secondary flow loss in the reverse vane area are reduced, and the overall efficiency of the multistage centrifugal pump is improved.

[0005] The technical scheme adopted by the application is a streamlined reverse vane optimization design method for a multistage centrifugal pump, which specifically includes the following steps:

[0006] Step 1: Numerical simulation is performed on the original reverse vane structure of the multistage centrifugal pump under the rated condition by using the ANSYS platform;

[0007] Step 2: The numerical simulation results obtained in step 1 are post-processed to obtain a flow line diagram in the flow passage of the original reverse vane structure, and a flow line is selected on the flow line diagram;

[0008] Step 3: Preliminary optimization is performed based on the flow line selected in step 2, and a streamlined line reaching the optimal hydraulic efficiency is selected;

[0009] Step 4, load the streamline obtained in step 3 to obtain a non-equal-thickness stream-shaped multi-stage centrifugal pump counter guide vane;

[0010] Step 5, iteratively optimize the counter guide vane structure obtained in step 4, and output the finally optimized stream-shaped counter guide vane structure of the multi-stage centrifugal pump.

[0011] The application also has the characteristics that:

[0012] In step 2, the specific process of selecting the streamline is as follows:

[0013] The streamline in the streamline diagram is sampled by B-spline interpolation, and the sampling point number is M, the radius of the original single circular arc counter guide vane blade streamline is R, and the curvature radius at the n point is r n , and the relative curvature radius at the n point is

[0014] In step 2, the selection principle of the streamline is as follows: 1) the relative curvature radius of any point of the streamline satisfies: 2) the curvatures of two consecutive points satisfy: The selected streamline is numbered, and the streamline selected by the above selection principle is the selected ith streamline, i.e. i=1, 2, 3…

[0015] The specific process of step 3 is as follows:

[0016] Step 3-1, the selected streamline is thickened along the two sides by 0.05R, and the leading and trailing edges of the thickened streamline structure are rounded to obtain a preliminary optimized counter guide vane, at this time, the preliminary optimized counter guide vane is a counter guide vane constructed by the selected first streamline as a streamline;

[0017] Step 3-2, the counter guide vane constructed by the selected first streamline as a streamline is re-simulated on the ANSYS platform under the rated working condition, when the hydraulic efficiency of the preliminary optimized counter guide vane is greater than that of the original counter guide vane, it indicates that the optimization is successful, the blade streamline determined to be successful is recorded as VANE-j and output to the standby library, j=1, 2, 3…, and the blade streamline determined to be unsuccessful is returned to step 2 to select the streamline again, the specific determination process is as follows:

[0018]

[0019] Wherein, η0 is the efficiency of the original counter guide vane structure, η i is the efficiency of the counter guide vane obtained after the preliminary optimization of the ith streamline as a streamline, ΔP IN is the total pressure at the inlet of the counter guide vane, ΔP OUT is the total pressure at the outlet of the counter guide vane, P W is the shaft power;

[0020] Step 3-3, after the iterative steps 3-1~3-2 are repeated constantly, at least 10 profile lines are screened out and stored in a candidate library, i.e., VANE-j, wherein j>=10, for the profile data VANE-j in the candidate library, the highest hydraulic efficiency is selected, and the profile line with the optimal hydraulic efficiency is recorded as VANE-max, and the mathematical expression of the highest hydraulic efficiency selection process is as follows:

[0021]

[0022] Wherein, η VANE-j / k is the efficiency of the reverse guide vane obtained after the preliminary optimization of VANE-j / k as the profile line, ΔP IN is the total pressure at the inlet of the reverse guide vane, ΔP OUT is the total pressure at the outlet of the reverse guide vane, P W is the shaft power.

[0023] The non-equal thickness model structure in step 4 is: including the main section of the reverse guide vane and the transition section of the reverse guide vane connected with the upper cover plate of the reverse guide vane and the lower cover plate of the reverse guide vane.

[0024] The specific process of step 5 is:

[0025] The streamline reverse guide vane loaded with the initial thickness model in step 4 is numerically simulated under the rated working condition, the load distribution curve of the reverse guide vane blade is obtained by processing the numerical simulation results in the ANSYS platform post-processing software;

[0026] When there are two or more peak inflection points in the load distribution curve of the rear cover plate, and the maximum amplitude difference between the load curve of the rear cover plate and the load curve of the front cover plate is greater than one fifth of the average load value, it is considered that the thickness loading model of the load distribution curve of the reverse guide vane is failed, the loading parameters are changed, and the thickness is reloaded;

[0027] When the cover plate load is greater than the front cover plate load, the two loads decrease along the relative flow direction length, and the maximum amplitude difference between the front and rear cover plate loads is less than one tenth of the average load value, the thickness model without peak inflection point of the load curve is determined as successful optimization, and the finally optimized reverse guide vane structure is output.

[0028] The beneficial effects of the present application are as follows:

[0029] 1. The blade profile of the multi-stage pump reverse guide vane provided by the present application is constructed by the streamline obtained by numerically simulating the initial model. Such design can make the blade geometry consistent with the flow trend of the liquid flow, effectively eliminate the fluid collision and vortex in the flow passage of the reverse guide vane, reduce the circulation, make the fluid flow more smooth, and achieve the purpose of reducing the flow loss such as blade profile loss.

[0030] 2. The multi-stage pump provided by the present application adopts different thicknesses for loading along the blade span of the reverse guide vane, which can form a structure similar to the end wall shaping and bending sweep. The obtained new model is subjected to numerical simulation to determine whether the load of the blade meets the requirements. Such structure can achieve the effect of end wall shaping and bending sweep, and can be combined with the two to provide more design freedom. Loading the blade with different thicknesses can eliminate the sharp change of the pressure gradient in the high turning area, weaken the channel vortex intensity at the end wall, disperse the load distribution of the blade, slow down the secondary flow loss in the vortex concentration area, and thus improve the overall efficiency of the centrifugal pump. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A prototype radial guide vane structure of a multi-stage centrifugal pump used in the flow line type reverse guide vane optimization design method of the present application;

[0032] Figure 2 A prototype reverse guide vane axial section view used in the flow line type reverse guide vane optimization design method of the present application;

[0033] Figure 3 A flow chart of the flow line type reverse guide vane optimization design method of the present application;

[0034] Figure 4 A numerical simulation streamline view of a prototype reverse guide vane used in the flow line type reverse guide vane optimization design method of the present application;

[0035] Figure 5 An axial section view of a flow line type multi-stage centrifugal pump reverse guide vane after preliminary optimization in the flow line type reverse guide vane optimization design method of the present application;

[0036] Figure 6 A blade spanwise section thickness loading schematic view of a flow line type multi-stage centrifugal pump reverse guide vane designed in the flow line type reverse guide vane optimization design method of the present application;

[0037] Figure 7 A numerical simulation streamline view of a reverse guide vane after flow line type optimization in the flow line type reverse guide vane optimization design method of the present application;

[0038] Figure 8 A non-uniform reverse guide vane load distribution curve view of a model with initial thickness loaded in the flow line type reverse guide vane optimization design method of the present application;

[0039] Figure 9 A reverse guide vane load distribution curve view of a finally optimized successful reverse guide vane in the flow line type reverse guide vane optimization design method of the present application;

[0040] Figure 10The radial guide vane structure diagram of the multistage centrifugal pump optimized by the multistage centrifugal pump streamline reverse guide vane optimization design method.

[0041] In the figure, 1 is a prototype reverse guide vane blade, 2 is an optimized reverse guide vane blade, 3 is a reverse guide vane upper cover plate, 4 is a reverse guide vane lower cover plate, 5 is a positive guide vane, 6 is a flow direction, 7 is a reverse guide vane inlet, 8 is a reverse guide vane outlet, 9 is a selected streamline, 10 is a rear cover plate load curve, 11 is a front cover plate load curve, 12 is a reverse guide vane main body, and 13 is a reverse guide vane transition section. DETAILED DESCRIPTION

[0042] The application will be described in detail below in combination with the drawings and specific embodiments.

[0043] The multistage centrifugal pump streamline reverse guide vane optimization design method of the application, as shown in the figure, Figure 1 The structure diagram of the prototype multistage centrifugal pump radial guide vane is shown, and the prototype reverse guide vane blade 1 is connected between the reverse guide vane upper cover plate 3 and the reverse guide vane lower cover plate 4. As shown in the figure, Figure 2 The middle section view of the prototype reverse guide vane of the multistage centrifugal pump is shown. After being pressurized by the upper stage impeller of the multistage centrifugal pump, the fluid flows into the radial guide vane structure, flows into the reverse guide vane outlet 8 from the reverse guide vane inlet 7 along the flow direction 6 in the reverse guide vane structure, and the liquid flowing out of the reverse guide vane outlet 8 enters the lower stage impeller to continue to be pressurized. Figure 1 The prototype multistage centrifugal pump radial guide vane structure shown is high-efficient, compact, economical, and convenient to install, and is suitable for various scenes, which is its inherent characteristics. Therefore, the application tries to optimize the reverse guide vane structure without changing the overall space volume of the structure. The specific optimization execution process is shown in the figure, Figure 1 The specific steps are as follows: Figure 3

[0044] Step 1, for the prototype multistage centrifugal pump reverse guide vane structure shown in the figure, Figure 2 Step 2, the numerical simulation results in step 1 are imported into the ANSYS platform post-processing software for processing to obtain the streamline diagram in the flow passage of the prototype multistage centrifugal pump radial guide vane structure shown in the figure. The streamline diagram will be selected by the following process:

[0045] Step 2, the numerical simulation results in step 1 are imported into the ANSYS platform post-processing software for processing to obtain the streamline diagram in the flow passage of the prototype multistage centrifugal pump radial guide vane structure shown in the figure. The streamline diagram will be selected by the following process: Figure 4

[0046] The streamline in the figure is sampled by B-spline interpolation, and the sampling point number is M, as shown in the figure, Figure 4 In the figure, the radius of the prototype reverse guide vane blade 1 profile line is R, and the curvature radius at the n point (n ∈ M) is r n , and the relative curvature radius at the n point is Figure 2 ​​​

[0047] To ensure that the optimized streamlined reverse guide vane can make the fluid flow more smoothly, and be more consistent with the flow trend of the fluid flow, the curvature of the selected streamline 9 should be able to ensure smooth change.

[0048] The selection principle of the streamline is as follows: 1) the relative curvature radius at any point of the streamline satisfies: The purpose of this boundary restriction is to prevent the wrap angle of the reverse guide vane blade from being too large, thereby causing greater losses such as flow separation; 2) the curvatures at two consecutive points satisfy: The purpose of this boundary restriction is to ensure that the fluid flows more smoothly along the flow direction 6.

[0049] In the streamline selection in Figure 4 , the selected streamlines are numbered. The streamline selected by the above selection principle is denoted as the selected ith streamline (i = 1, 2, 3…), as shown in Figure 4 , the selected streamline 9 is denoted as the selected first streamline.

[0050] Step 3, in this step, a loop is formed, and the optimization is iteratively performed.

[0051] Step 3-1, use the streamline 9 selected in step 2 (the selected first streamline) to construct the blade profile of the multi-stage pump reverse guide vane. Thicken the selected streamline 9 along both sides by 0.05R, and perform round corner processing on the front and rear edges of the thickened streamline structure, to obtain the preliminary optimized reverse guide vane blade 2 as shown in Figure 5 , at this time, the preliminary optimized reverse guide vane blade 2 is denoted as the reverse guide vane constructed by the selected first streamline as the profile;

[0052] Step 3-2, re-perform numerical simulation of the reverse guide vane constructed by the selected first streamline as the profile on the ANSYS platform under the rated operating condition, and calculate the blade profile efficiency according to the numerical simulation result, taking the improvement of the blade profile efficiency as the judgment of the success or failure of the optimization strategy, and requiring the hydraulic efficiency of the preliminary optimized reverse guide vane to be greater than that of the original reverse guide vane. The specific judgment process is as follows:

[0053]

[0054] Wherein, η0 is the efficiency of the original reverse guide vane structure, η i is the efficiency of the reverse guide vane obtained after preliminary optimization of the ith (i = 1, 2, 3…) streamline as the profile, ΔP IN is the total pressure at the inlet of the reverse guide vane, ΔP OUT is the total pressure at the outlet of the reverse guide vane, P W is the shaft power.

[0055] The vane profile determined as successful is recorded as VANE-j (j = 1, 2, 3…) and output to the candidate library, and the one determined as unsuccessful is returned to step 2 to select a stream line for construction again.

[0056] Step 3-3, after repeatedly iterating steps 3-1 and 3-2, at least 10 profile results are screened out and stored in the candidate library, i.e., VANE-j, j≥10, and the highest hydraulic efficiency is selected from the profile data in the candidate library VANE-j, and the mathematical expression of the highest hydraulic efficiency selection process is as follows:

[0057]

[0058] Wherein, η VANE-j / k is the efficiency of the reverse guide vane after preliminary optimization with VANE-j / k as the profile, ΔP IN is the total pressure at the inlet of the reverse guide vane, ΔP OUT is the total pressure at the outlet of the reverse guide vane, P W is the shaft power.

[0059] The profile with the optimal hydraulic efficiency is recorded as VANE-max, and output to the next step for further optimization.

[0060] Such design can make the blade geometry consistent with the flow trend of the liquid flow, effectively eliminate the fluid collision and vortex in the flow passage of the reverse guide vane, reduce the circulation, make the fluid flow more smooth, and achieve the purpose of reducing flow loss such as blade loss.

[0061] Step 4, a non-equal thickness model is loaded on the streamwise stacking line of the preliminary optimized streamline reverse guide vane VANE-max, to obtain a streamline multi-stage centrifugal pump reverse guide vane blade streamwise cross-sectional view as shown in Figure 6 In the figure, the center of gravity of the intersection of the reverse guide vane blade 2 and the reverse guide vane lower cover plate 4 is taken as the origin O, the origin O is directed to the shaft as the Y axis in the radial direction, and the origin O is directed to the upper cover plate 3 as the X axis in the streamwise stacking line, then the thickness loading model H is the distance from the reverse guide vane upper cover plate 3 to the reverse guide vane lower cover plate 4, and the model of the non-equal thickness reverse guide vane is composed of three parts, i.e., the reverse guide vane main section 12 and the transition section 13 connected with the reverse guide vane upper cover plate 3 and the reverse guide vane lower cover plate 4, wherein, D r1 , D r2 , D h1 , D h2 , D l1 , D l2 , D l3 are the reverse guide vane thickness model parameters that can be represented by H, D r1 , D r2 are the radii of the arc of the transition section 13 of the reverse guide vane main section 12 and the reverse guide vane upper cover plate 3 and the reverse guide vane lower cover plate 4, Dh1 D h2 D l2 D l3 D is the positioning parameter for the transition arc. l1 The thickness of the anti-missile blade body.

[0062] Since the prototype multistage centrifugal pump's guide vane structure has already undergone streamline optimization as described in steps 1-3 above, the streamline diagram obtained from numerical simulation of the streamlined guide vane is as follows. Figure 7 The streamline diagram shown is obtained from numerical simulation of the prototype anti-missile blade. Figure 4 In comparison, the hydraulic losses caused by secondary flows such as eddies resulting from the collision between the fluid along the flow direction 6 and the optimized anti-flying vane blade 2 have been significantly reduced. However, the large adverse pressure gradient between the optimized anti-flying vane blade 2 and the upper and lower cover plates 3 and 4 of the anti-flying vane results in hydraulic losses that cannot be ignored. Balancing the hydraulic efficiency and installation difficulty of the prototype multi-stage centrifugal pump anti-flying vane structure, this invention provides a thickness loading model. A non-uniform thickness model is used to load the preliminarily optimized streamlined anti-flying vane VANE-max along the spanwise stacking line (e.g., ...). Figure 6 Afterwards, a structure similar to endwall forming and blade sweep can be formed, which can significantly improve the flow pattern at the leading and trailing edges of the anti-missile blade, reduce secondary flow, and improve hydraulic efficiency. In the initial thickness loading model, H is the distance from the upper cover plate 3 to the lower cover plate 4 of the anti-missile blade. This is a fixed value in the optimization, then D... r1 =0.08H, D r2 =0.2H, D h1 =0.2H, D h2 =0.92H, D l1 =0.1H, D l2 =0.18H, D l3 =0.3H.

[0063] Step 5 forms a loop, continuously iterating and optimizing.

[0064] Step 5-1: Perform numerical simulation on the streamlined anti-missile blade after loading the initial thickness model in Step 4 under rated operating conditions. Import the numerical simulation results into the ANSYS platform post-processing software for processing to obtain the load distribution curve of the anti-missile blade. (See figure) Figure 8The figure shows the load distribution curves of the upper cover plate 3 and lower cover plate 4 of the guide vane after loading the initial thickness model of the prototype multistage centrifugal pump guide vane structure. The horizontal axis represents the relative flow length, i.e., the ratio of the length from the streamline node to the streamline origin to the total streamline length, denoted by `strreawise`. The vertical axis represents the load, denoted by `dimensionless pressure`. The load distribution curves of the guide vane blades are used to determine the load distribution in step 5-2.

[0065] Step 5-2: Determine the load distribution curves of the upper cover plate 3 and the lower cover plate 4 of the anti-missile blade after loading the initial thickness model. If similar... Figure 8 The anti-missile blade load distribution curves shown indicate that the rear cover plate load curve 10 has more than two peak inflection points, and the difference in the maximum amplitude between the rear cover plate load curve 10 and the front cover plate load curve 11 is greater than one-fifth of the average load value. Such a load distribution in the anti-missile blade structure leads to secondary flow and consequently a decrease in hydraulic efficiency. For similar... Figure 8 The anti-guide vane thickness loading model with this load distribution curve is judged as a failure, and D is changed. r1 D r2 D h1 D h2 D l1 D l2 D l3 The value is then used to reload the thickness. Numerical simulations are then performed on the reloaded anti-missile blade under rated operating conditions, and the load curve of the anti-missile blade after changing the thickness model is continuously evaluated through iterative assessments.

[0066] If similar issues occur during the iteration process Figure 9 The final optimized anti-missile blade load distribution curve shown in the figure maintains the load distribution given by the original scheme, such as... Figure 8 The load distribution trend shown is that the load 10 on the rear cover plate is greater than the load 11 on the front cover plate. The loads of the two plates decrease continuously along the relative flow direction. The maximum difference between the loads on the front and rear cover plates is less than one-tenth of the average load. The thickness model with no peak inflection point in the load curve is judged to be successfully optimized, and the output is the anti-guide vane structure obtained by the final successful optimization.

[0067] Step 6: After completing all the above steps, you will get the following result. Figure 10 Finally, the optimized multi-stage centrifugal pump anti-guide vane structure was completed, and the streamlined anti-guide vane optimization design method for multi-stage centrifugal pumps was finalized, resulting in the output anti-guide vane structure.

[0068] The basic reason that the span non-equal thickness streamline blade of the application can control the secondary flow inside the flow channel is that the radial component of the force of the blade on the liquid flow is not zero, the structure can eliminate the sharp change of the pressure gradient in the high turning area, balance the load distribution of the whole blade, weaken the channel vortex intensity at the end wall, slow down the secondary flow loss of the vortex concentration area near the end wall, weaken the pressure pulsation of the centrifugal pump, thereby improving the overall efficiency of the centrifugal pump. The span non-equal thickness blade can integrate the advantages of the end wall shaping and bending sweep, improve the reduction of the stress intensity of the blade caused by the bending sweep optimization, and provide more degrees of freedom for the optimization design of the blade profile. The application is based on the ANSYS platform, combines the numerical simulation of the full three-dimensional inverse problem optimization design of the flow part by using the design of experiment and the optimization algorithm, can complete the optimization design method of the reverse guide blade of the streamline of the multistage centrifugal pump in a short period, and obtain the best matching of the flow part parameters and the optimal effect of the pump efficiency.

Claims

1. A method for optimal design of stream-lined counter-guide vanes of a multi-stage centrifugal pump, characterized in that: Specifically comprising the following steps: Step 1, numerical simulation is carried out on the original multi-stage centrifugal pump counter-guide vane structure under the rated operating condition by using ANSYS platform; Step 2, the numerical simulation results obtained in step 1 are post-processed to obtain the streamlines in the flow passage of the original counter-guide vane structure, and the streamlines are selected on the streamline diagram; In step 2, the specific process of selecting the streamlines is as follows: B-spline interpolation sampling is performed on the streamlines in the streamline diagram, the number of sampling points is M, the radius of the prototype single circular-arc reverse guide vane blade profile is denoted as R, and the curvature radius at the n point is denoted as r n , and the relative curvature radius at the n point is denoted as =r n / R. The selection principle of the streamlines in step 2 is as follows: 1) the relative curvature radius of any point of the streamline satisfies: 0.02< <1.25; 2) the curvatures of two continuous points satisfy: 0.8< / <1.2; the selected streamlines are numbered, and the streamline selected by the above selection principle is denoted as the selected ith streamline, i = 1, 2, 3, … Step 3, based on the streamlines selected in step 2, preliminary optimization is carried out, and the streamline profile achieving the optimal hydraulic efficiency is selected; The specific process of step 3 is as follows: Step 3-1, the streamlines selected in step 2 are thickened along the two sides by 0.05R, and the leading and trailing edges of the thickened streamline structure are rounded to obtain the preliminary optimized counter-guide vane, at this time, the preliminary optimized counter-guide vane is denoted as the counter-guide vane constructed by the selected i-th streamline as the profile; Step 3-2, the counter-guide vane constructed by the selected i-th streamline as the profile is re-simulated under the rated operating condition on the ANSYS platform, when the hydraulic efficiency of the preliminary optimized counter-guide vane is greater than that of the original counter-guide vane, it indicates that the optimization is successful, the vane profile determined to be successful is denoted as VANE-j and output to the candidate library, j=1, 2, 3…, and the vane profile determined to be unsuccessful is returned to step 2 to select the streamline again for construction; Step 3-3, after repeatedly iterating steps 3-1~3-2, at least 10 streamline results are screened out and stored in the candidate library, i.e. VANE-j, j≥10, and the highest hydraulic efficiency is selected from the streamline data in the candidate library VANE-j, and the optimal hydraulic efficiency profile is denoted as VANE-max; Step 4, the profile obtained in step 3 is loaded to obtain a non-equal-thickness streamline profile multi-stage centrifugal pump counter-guide vane; Step 5, the counter-guide vane structure obtained in step 4 is iteratively optimized, and the finally optimized multi-stage centrifugal pump streamline profile counter-guide vane structure is output.

2. The method of claim 1, wherein: The non-equal-thickness model structure in step 4 includes a counter-guide vane main section (12) and a counter-guide vane transition section (13) connected with a counter-guide vane front cover plate (3) and a counter-guide vane rear cover plate (4).

3. The method of claim 2, wherein: The specific process of step 5 is as follows: The streamline profile counter-guide vane after loading the initial thickness model in step 4 is simulated under the rated operating condition, the simulation results are imported into the ANSYS platform post-processing software for processing, and the load distribution curve of the counter-guide vane blade is obtained; When there are two or more peak inflection points in the load distribution curve, the maximum amplitude difference between the rear cover plate load curve and the front cover plate load curve is greater than one fifth of the average load, the counter-guide vane thickness loading model of the load distribution curve is determined to be unsuccessful, the loading parameters are changed, and the thickness loading is re-performed; When the rear cover plate load is greater than the front cover plate load, both of them decrease along the relative flow direction, and the maximum amplitude difference between the front and rear cover plate loads is less than one tenth of the average load, and there is no peak inflection point in the load curve, it is determined that the thickness model is successfully optimized, and the finally optimized counter-guide vane structure is output.

Images