A hydraulic design method and system suitable for coupling and matching of guide vanes of an impeller of a high specific speed submersible axial flow pump

Abstract

This invention discloses a hydraulic design method and system for impeller-guide vane coupling matching of high specific speed submersible axial flow pumps, belonging to the field of fluid machinery technology. The method includes the following steps: S1, accurate calculation of impeller diameter; S2, hub ratio graded optimization; S3, blade cascade density collaborative design; S4, blade comprehensive parameter design; S5, guide vane hydraulic quantitative design; S6, dynamic coupling matching of impeller and guide vane. It aims to overcome the inherent defects of existing high specific speed submersible axial flow pump hydraulic design technology, and fundamentally solves the problems of large deviations in actual pump performance and poor adaptability across wide specific speed ranges caused by reliance on model pump similarity conversion in existing technologies. Simultaneously, it addresses the problems of excessive pressure pulsation and insufficient operational stability caused by the lack of impeller-guide vane coupling matching in existing designs, as well as the industry pain points of parameter values ​​lacking systematic theoretical support and the inability to simultaneously achieve high efficiency and cavitation resistance due to empirical design.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery technology, and more specifically, to a hydraulic design method and system for coupling and matching impeller guide vanes of high specific speed submersible axial flow pumps. Background Technology

[0002] Axial flow pumps, as typical high specific speed fluid machinery, have become core power equipment for major livelihood and infrastructure projects such as municipal water supply and drainage, farmland irrigation, watershed flood control and drainage, and cross-regional water resource allocation, thanks to their core advantages such as large flow rate, compact structure, convenient installation, and small footprint. Among them, high specific speed submersible axial flow pumps with a specific speed in the range of 700 to 1600 are the main models for low head and large flow rate operating conditions, and their hydraulic performance directly determines the operating efficiency, energy consumption level, and long-term service stability of the project.

[0003] Currently, the industry generally adopts a similarity conversion method based on standard model pumps for the hydraulic design of this type of axial flow pump. That is, relying on a standard model pump that has completed on-site testing and verification, the parameters of the actual pump are converted using the proportional law and the cutting law in the similarity principle. Although this method simplifies the design process, it has inherent technical defects that are difficult to overcome:

[0004] The conversion has limited applicability. When the conversion coefficients for the speed and size of the actual pump and the model pump exceed the reasonable range, it will cause flow field distortion, intensified boundary layer separation, and premature cavitation initiation, resulting in large fluctuations in the head of the actual pump and a significant decrease in operating efficiency.

[0005] Poor parameter adaptability: Existing standard model pumps are mostly optimized for the low to medium specific speed range of 500 to 800, making it difficult to adapt to the high specific speed conditions of a wide range of 700 to 1600, and thus unable to balance high efficiency and cavitation resistance.

[0006] The lack of coupling matching design and the failure of traditional methods to consider the dynamic coupling relationship between the impeller and the guide vane can easily lead to harmonic resonance and excessive pressure pulsation, resulting in excessive operating noise and vibration, which seriously affects the service life of the equipment.

[0007] Furthermore, existing designs for high specific speed axial flow pumps largely rely on scattered empirical formulas, and the key parameter values ​​lack systematic theoretical support and quantitative optimization, resulting in poor performance consistency under different operating conditions and failing to meet the core requirements of major projects for efficient, stable, and low-noise operation of pump sets. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention aims to provide a hydraulic design method and system suitable for impeller-guide vane coupling matching of high specific speed submersible axial flow pumps. This method aims to overcome the inherent defects of existing hydraulic design technologies for high specific speed submersible axial flow pumps, and to fundamentally solve the problems of large deviations in actual pump performance, low operating efficiency, and poor adaptability across wide specific speed ranges caused by reliance on model pump similarity conversions in existing technologies. Simultaneously, it addresses the problems of excessive pressure pulsation, high vibration and noise, and insufficient operational stability caused by the lack of impeller-guide vane coupling matching in existing designs, as well as the industry pain points of parameter values ​​lacking systematic theoretical support and the inability to simultaneously achieve high efficiency and cavitation resistance due to empirical design.

[0009] To solve the above problems, the present invention adopts the following technical solution.

[0010] A hydraulic design method for coupling and matching impeller guide vanes of high specific speed submersible axial flow pumps, wherein the high specific speed is defined as a specific speed within a preset range, and this range is divided into at least two sub-ranges according to the specific speed, the method is based on the coupling of lift method correction and streamline method to achieve the design, and includes the following steps:

[0011] S1. Accurate calculation of impeller diameter: Obtain the design flow rate, motor speed and corresponding characteristic values, obtain the basic diameter based on the design flow rate and characteristic values, construct a compensation coefficient using the difference between the required and allowable net positive suction head (NPSH) to correct the basic diameter, and fine-tune it in combination with the standard motor speed.

[0012] S2. Hub ratio graded optimization: The ratio of hub diameter to impeller diameter is set to increase as the specific speed decreases within the sub-interval, and its lower limit is a linear function with a constant term that is positively correlated with the specific speed.

[0013] S3, Blade cascade density collaborative design: Set the ratio of the blade chord length to the distance between the arc lengths of adjacent blades in the same impeller within each sub-section to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub;

[0014] S4. Blade integrated parameter design: The number of impeller blades is determined based on sub-intervals, and the blade natural frequency is verified by a preset multiple that is greater than the fluid excitation frequency; the blade thickness is set to increase linearly from the rim to the hub and the gradual slope is determined; the 791 airfoil is adopted and the leading edge is rounded to a fixed ratio based on the chord length.

[0015] S5. Quantitative hydraulic design of guide vanes: Obtain the actual streamline lengths of the three sections at the inlet, middle, and outlet of the guide vane flow channel; the guide vane airfoil chord length is positively correlated with this length and energy recovery efficiency, the guide vane skelet radius is positively correlated with this chord length, and both are negatively correlated with the trigonometric function based on the inlet and outlet angle construction; the guide vane adopts the same 791 airfoil as the impeller with a fixed tail edge thinning ratio;

[0016] S6. Dynamic coupling matching between impeller and guide vane: Determine the overall range of the number of guide vane blades and allocate sub-ranges according to sub-intervals. Constrain the number of guide vane blades to be no multiple of the number of impeller blades and the absolute value of the difference in number to be no equal to 1. Construct a complete impeller-guide vane coupling design method that is suitable for a wide range of high specific speed conditions and can simultaneously improve the pump's operating efficiency, operating stability and anti-cavitation performance.

[0017] As a further technical solution of the present invention, the precise calculation of the S1 impeller diameter specifically includes the following sub-steps:

[0018] S11: Determine the corresponding characteristic value based on the preset high specific speed range of the submersible axial flow pump. The range of values ​​for;

[0019] S12: Obtain Design Flow Combined with the aforementioned feature values The impeller base diameter is calculated.

[0020] S13: Obtain the required net positive suction head (NPSH) and allowable NPSH under the design conditions. Based on the difference between the two, construct a cavitation risk compensation coefficient. Perform a secondary correction on the impeller base diameter and combine it with a reverse fine-tuning of the standard motor speed to obtain the final impeller diameter. The step-by-step execution process for impeller diameter calculation has been refined, which can accurately control the design accuracy of impeller size and lay the foundation for subsequent cavitation compensation and full parameter matching.

[0021] As a further technical solution of the present invention, the complete impeller diameter The calculation formula consists of multiplying the foundation diameter portion by the cavitation risk compensation portion; wherein, the foundation diameter portion is multiplied by the design flow rate. and eigenvalues The ratio is proportional to the specified root of the ratio; the cavitation risk compensation portion is composed of a constant 1 plus a value based on the required net positive suction head (NPSH). With allowable net positive suction head (NPSH) The difference and the allowable net positive suction head (NPSH) constitute the correction term; the cavitation risk compensation coefficient is based on the required NPSH. With allowable net positive suction head (NPSH) The difference is constructed, and the compensation coefficient is used to... A second correction is performed to compensate for cavitation risks. The calculation logic and characteristic value range of the impeller diameter are clarified, which can accurately match different specific speed conditions, effectively compensate for cavitation risks, and ensure design reliability.

[0022] As a further technical solution of the present invention, the hydraulic quantitative design of the S5 guide vane specifically includes the following sub-steps:

[0023] S51: Extract the actual streamline lengths of the inlet, intermediate, and outlet sections within the guide vane channel. ;

[0024] S52: Based on the actual length of the streamline Guide vane energy recovery efficiency and the inlet angle of the guide vane blades Exit Angle The guide vane airfoil chord length was calculated. ;

[0025] S53: Based on the airfoil chord length of the guide vane and imported corner Exit Angle The radius of the guide vane rib is calculated. The step-by-step calculation process of the guide vane hydraulic parameters has been refined, which can accurately control the airfoil and rib line size of the guide vane and maximize the energy recovery efficiency of the guide vane.

[0026] As a further technical solution of the present invention, the guide vane airfoil chord length Based on the actual length of the streamline With guide vane energy recovery efficiency The product of the two, divided by the inlet angle With exit angle The radius of the guide vane rib is calculated by taking the sine of half the sum of the two values. Based on the airfoil chord length Divide by the exit angle With the import angle The calculation is based on a preset multiple of half the sine value of the difference. This claim clarifies the calculation logic and value constraints of the core parameters of the guide vane, which can ensure smooth fluid turning, reduce flow loss, and improve the energy conversion efficiency of the guide vane.

[0027] As a further technical solution of the present invention, the dynamic coupling and matching of the S6 impeller and the guide vane specifically includes the following sub-steps:

[0028] S61: Determine the number of guide vane blades based on the preset high specific speed range. The overall range of values, and the corresponding sub-ranges are assigned according to the specific speed sub-ranges;

[0029] S62: Calculate the number of guide vane blades With the number of impeller blades The modulo operation results are used to verify that the two are not multiples of each other; S63: Calculate and The absolute value of the difference between the two is used to verify that the absolute value of the difference is not equal to 1, thus completing the exclusive coupling matching. This refines the coupling matching verification process between the impeller and the guide vane, which can avoid the risk of harmonic resonance from the root and significantly reduce the pressure pulsation amplitude during pump operation.

[0030] As a further technical solution of the present invention, the and The optimal matching combination is: when the number of impeller blades At that time, the number of guide vane blades Choose 7 or 8; when the number of impeller blades At that time, the number of guide vane blades Choosing 9 clarifies the optimal matching combination of the number of impeller and guide vane blades, which can achieve optimal flow field synergy, further reduce pressure pulsation, and improve the operational stability of the pump unit.

[0031] As a further technical solution of the present invention, the following parameter limitation is also included: defining the hub ratio. Hub diameter With impeller diameter The ratio, the The constraint to be satisfied is: the hub ratio Greater than or equal to based on specific speed A linear function relating the speed to a preset reference speed, wherein the linear function includes a positive proportional coefficient term and a constant compensation term; the blade cascade density is defined as the blade chord length. Spacing between blades The ratio of, where The distance between adjacent blades on the same impeller along the same circumference is the arc length of the blades. The specific value range for this distance is as follows:

[0032] when At that time, the density of the blade cascade at the hub Blade density at the rim ;

[0033] when At that time, the density of the blade cascade at the hub Blade density at the rim The constraint logic of hub ratio and the range of values ​​for blade density are clearly defined, which can balance the flow channel unobstructedness and blade strength, and effectively suppress the flow separation phenomenon in the flow channel.

[0034] As a further technical solution of the present invention, the following blade parameter limitation is also included: the blade thickness has a linearly gradual slope from the rim to the hub. This is the ratio of the difference in blade thickness between the hub and the rim to the difference in blade chord length between the hub and the rim. Leading edge rounding radius of the airfoil With the chord length of the blade They are in a fixed proportional relationship; both the impeller blades and guide vanes adopt the 791 airfoil shape, and the trailing edge of the blades is thinned in a fixed proportion, with a trailing edge thickness of... Length of the leaf chord By multiplying by a preset trailing edge thinning ratio constant, the rules for gradual blade thickness variation and airfoil optimization are clarified, which can effectively reduce flow resistance, suppress cavitation initiation, reduce wake loss, and extend blade service life.

[0035] A hydraulic design system for coupling and matching impeller and guide vane of a high specific speed submersible axial flow pump is provided. The high specific speed refers to the specific speed of the submersible axial flow pump falling within a preset high specific speed range. This preset high specific speed range is divided into at least two sub-ranges based on the magnitude of the specific speed. The system achieves the hydraulic design of the impeller and guide vane based on a lift method correction and a streamline method coupling. The system includes:

[0036] Impeller diameter precision calculation module: used to obtain the design flow rate and motor speed, determine the characteristic value of the corresponding high specific speed range; based on the design flow rate and characteristic value, the impeller base diameter is obtained, and the cavitation risk compensation coefficient is constructed by using the difference between the required net positive suction head (NPSH) and the allowable NPSH under the design conditions, and the impeller base diameter is corrected in the second way, and fine-tuned in the reverse direction in combination with the standard motor speed;

[0037] Hub ratio grading optimization module: used to set the ratio of hub diameter to impeller diameter to increase as the specific speed decreases within the sub-interval, and the lower limit of this ratio is a linear function with a constant term that is positively correlated with the specific speed.

[0038] Blade density collaborative design module: used to set the ratio of blade chord length to arc length spacing in each sub-interval to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub;

[0039] Blade integrated parameter design module: used to determine the number of impeller blades based on specific speed sub-range, and to perform resonance verification with the blade natural frequency being greater than a preset multiple of the fluid excitation frequency; to set the blade thickness to increase linearly from the rim to the hub along the chord length direction, and to determine its thickness linear gradient slope; to use the 791 airfoil as the impeller blade cross-sectional shape, and to perform fixed-proportion rounding optimization on the airfoil leading edge based on the blade chord length;

[0040] Guide vane hydraulic quantitative design module: used to obtain the actual streamline lengths of the inlet, middle and outlet sections in the guide vane flow channel; to make the guide vane airfoil chord length positively correlated with the actual streamline lengths of the three sections in the flow channel and the energy recovery efficiency, and the guide vane skelet radius positively correlated with the chord length, and both negatively correlated with the trigonometric function based on the inlet and outlet angle construction; using the same 791 airfoil as the impeller with a fixed tail edge thinning ratio as the guide vane blade;

[0041] The impeller and guide vane dynamic coupling matching module is used to determine the overall range of the number of guide vane blades and allocate corresponding sub-ranges according to different specific speed sub-ranges; it executes exclusive coupling matching constraints, that is, the number of guide vane blades and the number of impeller blades are not multiples of each other, and the absolute value of the difference between the two is not equal to 1. It constructs a functional module system that corresponds one-to-one with the design method, which can realize the standardized execution of the hydraulic design process and greatly improve design efficiency and parameter consistency.

[0042] Compared with the prior art, the advantages of this invention are:

[0043] This invention establishes hierarchical constraints and linear correlation rules for hub ratio and blade cascade density with specific speed by dividing the high specific speed range into sub-intervals. This breaks through the working condition limitations of traditional model-to-analysis algorithms, can adapt to a wide range of high specific speed working conditions, balances blade strength and flow channel unobstructedness, effectively suppresses flow field distortion and boundary layer separation, and improves the operating efficiency under all working conditions.

[0044] By using the impeller diameter precision calculation logic with cavitation risk compensation, a correction mechanism is built based on the difference between the required and allowable cavitation margin. While ensuring hydraulic performance, this effectively delays the initiation of cavitation, significantly improves the pump set's anti-cavitation performance, and extends the service life of the equipment.

[0045] By using the exclusive coupling constraint of the number of impeller and guide vane blades, the risk of harmonic resonance is avoided from the root, significantly reducing the pressure pulsation, vibration and noise of the pump unit, and solving the problem of poor operation stability caused by insufficient coupling in traditional design.

[0046] Through quantitative design of guide vane airfoil and bone line and refined optimization of 791 airfoil, the energy recovery efficiency of guide vane is maximized, flow loss and wake loss are reduced, the hydraulic efficiency of pump set is further improved, and long-term operating energy consumption is reduced.

[0047] This invention forms a complete and standardized hydraulic design system that can fully meet the core requirements of major water conservancy and municipal projects for efficient, stable, and low-noise operation of pump sets. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0049] Figure 2 This is a schematic diagram illustrating the relative thickness variation of the airfoil according to the present invention;

[0050] Figure 3 This is a diagram illustrating the density of the cascade in this invention;

[0051] Figure 4 This is a flow path diagram of the guide vane of the present invention;

[0052] Figure 5 This is a diagram of the airfoil of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] This invention provides an embodiment 1

[0055] Please see Figure 1 A hydraulic design method for coupling and matching impeller guide vanes of high specific speed submersible axial flow pumps is disclosed. The high specific speed is defined as a specific speed within a preset range, which is divided into at least two sub-ranges based on the specific speed. The method is based on a combination of lift method correction and streamline method, and includes the following steps:

[0056] S1. Accurate calculation of impeller diameter: Obtain the design flow rate, motor speed and corresponding characteristic values, obtain the basic diameter based on the design flow rate and characteristic values, construct a compensation coefficient using the difference between the required and allowable net positive suction head (NPSH) to correct the basic diameter, and fine-tune it in combination with the standard motor speed.

[0057] S2. Hub ratio graded optimization: The ratio of hub diameter to impeller diameter is set to increase as the specific speed decreases within the sub-interval, and its lower limit is a linear function with a constant term that is positively correlated with the specific speed.

[0058] S3, Blade cascade density collaborative design: Set the ratio of the blade chord length to the distance between the arc lengths of adjacent blades in the same impeller within each sub-section to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub;

[0059] S4. Blade integrated parameter design: The number of impeller blades is determined based on sub-intervals, and the blade natural frequency is verified by a preset multiple that is greater than the fluid excitation frequency; the blade thickness is set to increase linearly from the rim to the hub and the gradual slope is determined; the 791 airfoil is adopted and the leading edge is rounded to a fixed ratio based on the chord length.

[0060] S5. Quantitative hydraulic design of guide vanes: Obtain the actual streamline lengths of the three sections at the inlet, middle, and outlet of the guide vane flow channel; the guide vane airfoil chord length is positively correlated with this length and energy recovery efficiency, the guide vane skelet radius is positively correlated with this chord length, and both are negatively correlated with the trigonometric function based on the inlet and outlet angle construction; the guide vane adopts the same 791 airfoil as the impeller with a fixed tail edge thinning ratio;

[0061] S6. Dynamic coupling matching between impeller and guide vane: Determine the overall range of the number of guide vane blades and allocate sub-ranges according to sub-intervals. Constrain the number of guide vane blades to be no multiple of the number of impeller blades and the absolute value of the difference in number to be no equal to 1. Construct a complete impeller-guide vane coupling design method, which is suitable for a wide range of high specific speed conditions and can simultaneously improve the pump body's operating efficiency, operating stability and anti-cavitation performance.

[0062] The precise calculation of the S1 impeller diameter specifically includes the following sub-steps:

[0063] S11: Determine the corresponding characteristic value based on the preset high specific speed range of the submersible axial flow pump. The range of values ​​for;

[0064] S12: Obtain Design Flow Combined with the aforementioned feature values The impeller base diameter is calculated.

[0065] S13: Obtain the required net positive suction head (NPSH) and allowable NPSH under the design conditions. Based on the difference between the two, construct a cavitation risk compensation coefficient. Perform a secondary correction on the impeller base diameter and combine it with a reverse fine-tuning of the standard motor speed to obtain the final impeller diameter. The step-by-step execution process for impeller diameter calculation has been refined, which can accurately control the design accuracy of impeller size and lay the foundation for subsequent cavitation compensation and full parameter matching.

[0066] The complete impeller diameter The calculation formula consists of multiplying the foundation diameter portion by the cavitation risk compensation portion; wherein, the foundation diameter portion is multiplied by the design flow rate. and eigenvalues The ratio is proportional to the specified root of the ratio; the cavitation risk compensation portion is composed of a constant 1 plus a value based on the required net positive suction head (NPSH). With allowable net positive suction head (NPSH) The difference and the allowable net positive suction head (NPSH) constitute the correction term; the cavitation risk compensation coefficient is based on the required NPSH. With allowable net positive suction head (NPSH) The difference is constructed, and the compensation coefficient is used to... A second correction is made to achieve cavitation risk compensation. The calculation logic and characteristic value range of the impeller diameter are clarified, which can accurately match different specific speed conditions, effectively compensate for cavitation risks, and ensure design reliability.

[0067] The S5 guide vane hydraulic quantitative design specifically includes the following sub-steps:

[0068] S51: Extract the actual streamline lengths of the inlet, intermediate, and outlet sections within the guide vane channel. ;

[0069] S52: Based on the actual length of the streamline Guide vane energy recovery efficiency and the inlet angle of the guide vane blades Exit Angle The guide vane airfoil chord length was calculated. ;

[0070] S53: Based on the airfoil chord length of the guide vane and imported corner Exit Angle The radius of the guide vane rib is calculated. The step-by-step calculation process of the guide vane hydraulic parameters has been refined, which can accurately control the airfoil and rib line size of the guide vane and maximize the energy recovery efficiency of the guide vane.

[0071] The guide vane airfoil chord Based on the actual length of the streamline With guide vane energy recovery efficiency The product of the two, divided by the inlet angle With exit angle The radius of the guide vane rib is calculated by taking the sine of half the sum of the two values. Based on the airfoil chord length Divide by the exit angle With the import angle The calculation is based on a preset multiple of half the sine value of the difference. This claim clarifies the calculation logic and value constraints of the core parameters of the guide vane, which can ensure smooth fluid turning, reduce flow loss, and improve the energy conversion efficiency of the guide vane.

[0072] The dynamic coupling and matching of the S6 impeller and guide vane specifically includes the following sub-steps:

[0073] S61: Determine the number of guide vane blades based on the preset high specific speed range. The overall range of values, and the corresponding sub-ranges are assigned according to the specific speed sub-ranges;

[0074] S62: Calculate the number of guide vane blades With the number of impeller blades The modulo operation results are used to verify that the two are not multiples of each other; S63: Calculate and The absolute value of the difference between the two is used to verify that the absolute value of the difference is not equal to 1, thus completing the exclusive coupling matching. This refines the coupling matching verification process between the impeller and the guide vane, which can fundamentally avoid the risk of harmonic resonance and significantly reduce the pressure pulsation amplitude during pump operation.

[0075] The and The optimal matching combination is: when the number of impeller blades At that time, the number of guide vane blades Choose 7 or 8; when the number of impeller blades At that time, the number of guide vane blades Choosing 9 clarifies the optimal matching combination of the number of impeller and guide vane blades, which can achieve optimal flow field synergy, further reduce pressure pulsation, and improve the operational stability of the pump unit;

[0076] It also includes the following parameter limitations: defining the hub ratio. Hub diameter With impeller diameter The ratio, the The constraint to be satisfied is: the hub ratio Greater than or equal to based on specific speed A linear function relating the speed to a preset reference speed, wherein the linear function includes a positive proportional coefficient term and a constant compensation term; the blade cascade density is defined as the blade chord length. Spacing between blades The ratio of, where The distance between adjacent blades on the same impeller along the same circumference is the arc length of the blades. The specific value range for this distance is as follows:

[0077] when At that time, the density of the blade cascade at the hub Blade density at the rim ;

[0078] when At that time, the density of the blade cascade at the hub Blade density at the rim The constraint logic of hub ratio and the range of values ​​for blade density are clearly defined, which can balance the flow channel unobstructedness and blade strength, and effectively suppress the flow separation phenomenon in the flow channel.

[0079] This also includes the following blade parameter constraints: the linear gradient slope of the blade thickness from the rim to the hub. This is the ratio of the difference in blade thickness between the hub and the rim to the difference in blade chord length between the hub and the rim. Leading edge rounding radius of the airfoil With the chord length of the blade They are in a fixed proportional relationship; both the impeller blades and guide vanes adopt the 791 airfoil shape, and the trailing edge of the blades is thinned in a fixed proportion, with a trailing edge thickness of... Length of the leaf chord Multiplying by the preset trailing edge thinning ratio constant clarifies the blade thickness gradient and airfoil optimization rules, which can effectively reduce flow resistance, suppress cavitation initiation, reduce wake loss, and extend blade service life.

[0080] This invention provides an embodiment 2

[0081] A hydraulic design system for coupling and matching impeller and guide vane of a high specific speed submersible axial flow pump is provided. The high specific speed refers to the specific speed of the submersible axial flow pump falling within a preset high specific speed range. This preset high specific speed range is divided into at least two sub-ranges based on the magnitude of the specific speed. The system achieves the hydraulic design of the impeller and guide vane based on a lift method correction and a streamline method coupling. The system includes:

[0082] Impeller diameter precision calculation module: used to obtain the design flow rate and motor speed, determine the characteristic value of the corresponding high specific speed range; based on the design flow rate and characteristic value, the impeller base diameter is obtained, and the cavitation risk compensation coefficient is constructed by using the difference between the required net positive suction head (NPSH) and the allowable NPSH under the design conditions, and the impeller base diameter is corrected in the second way, and fine-tuned in the reverse direction in combination with the standard motor speed;

[0083] Hub ratio grading optimization module: used to set the ratio of hub diameter to impeller diameter to increase as the specific speed decreases within the sub-interval, and the lower limit of this ratio is a linear function with a constant term that is positively correlated with the specific speed.

[0084] Blade density collaborative design module: used to set the ratio of blade chord length to arc length spacing in each sub-interval to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub;

[0085] Blade integrated parameter design module: used to determine the number of impeller blades based on specific speed sub-range, and to perform resonance verification with the blade natural frequency being greater than a preset multiple of the fluid excitation frequency; to set the blade thickness to increase linearly from the rim to the hub along the chord length direction, and to determine its thickness linear gradient slope; to use the 791 airfoil as the impeller blade cross-sectional shape, and to perform fixed-proportion rounding optimization on the airfoil leading edge based on the blade chord length;

[0086] Guide vane hydraulic quantitative design module: used to obtain the actual streamline lengths of the inlet, middle and outlet sections in the guide vane flow channel; to make the guide vane airfoil chord length positively correlated with the actual streamline lengths of the three sections in the flow channel and the energy recovery efficiency, and the guide vane skelet radius positively correlated with the chord length, and both negatively correlated with the trigonometric function based on the inlet and outlet angle construction; using the same 791 airfoil as the impeller with a fixed tail edge thinning ratio as the guide vane blade;

[0087] The impeller and guide vane dynamic coupling matching module is used to determine the overall range of the number of guide vane blades and allocate corresponding sub-ranges according to different specific speed sub-ranges; it executes exclusive coupling matching constraints, that is, the number of guide vane blades and the number of impeller blades are not multiples of each other, and the absolute value of the difference between the two is not equal to 1. It constructs a functional module system that corresponds one-to-one with the design method, which can realize the standardized execution of the hydraulic design process and greatly improve design efficiency and parameter consistency.

[0088] This invention provides an application example

[0089] S1. Accurate calculation of impeller diameter: Obtain the design flow rate, motor speed, and corresponding characteristic values. Based on the design flow rate and characteristic values, obtain the basic diameter. Use the difference between the required and allowable net positive suction head (NPSH) to construct a compensation coefficient to correct the basic diameter, and then fine-tune it in conjunction with the standard motor speed. Specifically:

[0090] Impeller design is carried out in the following steps, with each parameter forming a strong coupling relationship with the specific speed, while incorporating cavitation suppression design concepts:

[0091] The impeller diameter D is accurately calculated using the formula to determine the base diameter:

[0092]

[0093] In the formula, For design flow rate, the unit is ; for Eigenvalues; Motor speed, unit: ; This is the required net positive suction head (NPSH) under the design operating conditions. To allow for net positive suction head (NPSH);

[0094] The The specific range of values ​​is: when hour, Pick ;when hour, Pick ;

[0095] After calculation and considering the available motor speeds, the standard motor speeds are preferentially selected: 750 r / min, 980 r / min, 1480 r / min, and 2950 r / min. The impeller diameter is then finely adjusted in the reverse direction to ensure the matching of speed and diameter and to achieve economic efficiency.

[0096] S2. Hub Ratio Graded Optimization: The ratio of hub diameter to impeller diameter is set to increase as the specific speed decreases within the sub-interval, and its lower limit is a linear function with a constant term that is positively correlated with the specific speed. Specifically:

[0097] The hub ratio is the ratio of the hub diameter to the impeller diameter, and it is selected in stages according to the specific speed range, while taking into account both strength and flow channel unobstructedness.

[0098] When 700 < When the speed is ≤1000, d=0.4~0.5, and the smaller the specific speed, the larger the hub ratio value. For example: When the value is 750, d = 0.48. =950, d=0.42, to ensure the strength of the blade root and the uniformity of the flow field;

[0099] When 1000 < When the speed is ≤1500, d=0.3~0.42, and the smaller the specific speed, the larger the hub ratio value, to balance the flow capacity and thrust bearing requirements;

[0100] Value constraint: The hub ratio d must satisfy d ≥ 0.3 × ( / 1000)+0.25, to avoid overloading the thrust bearing due to an undersized wheel hub;

[0101] S3. Blade cascade density collaborative design: The ratio of the blade chord length to the arc length spacing between adjacent blades in each sub-section is set to increase as the specific speed decreases, and this ratio at the rim is not less than a preset percentage at the hub, specifically:

[0102] Collaborative design of blade cascade density (l / t):

[0103] The blade density is the ratio of the blade chord length (l) to the blade spacing (t), and is graded for the hub (h) and rim (0) respectively, while considering flow separation suppression:

[0104] When 700 < When ≤1000: at the hub (l / t) h = 0.95~1.0, at the rim (l / t) 0 = 0.7~0.85; when 1000 < For values ​​≤1500: h at the hub (l / t) = 0.7~0.85, 0 at the rim (l / t) = 0.62~0.65; Core design principle:

[0105] Within the same specific speed range, the smaller the specific speed, the larger the value of the blade cascade density, which suppresses flow separation by increasing the force-bearing area of ​​the blades;

[0106] The blade density at the rim must not be less than 65% of that at the hub to ensure a gradual transition of the flow channel in the radial direction;

[0107] t is the arc length distance between adjacent blades on the same circumference;

[0108] S4. Blade Integrated Parameter Design: The number of impeller blades is determined based on sub-intervals, and the blade natural frequency is verified by a preset multiple greater than the fluid excitation frequency; the blade thickness is set to increase linearly from the rim to the hub, and a gradual slope is determined. A 791 airfoil is adopted, and the leading edge is rounded to a fixed ratio based on the chord length. Specifically:

[0109] Number of leaves Optimized selection:

[0110] The and The optimal matching combination is: when the number of impeller blades At that time, the number of guide vane blades Choose 7 or 8; when the number of impeller blades At that time, the number of guide vane blades Choosing 9 clarifies the optimal matching combination of the number of impeller and guide vane blades, which can achieve optimal flow field synergy, further reduce pressure pulsation, and improve the operational stability of the pump unit;

[0111] The formula for calculating the linearly gradual slope of blade thickness from the rim to the hub is:

[0112]

[0113] and ,in The thickness of the blades at the hub. The thickness of the blade at the rim is [missing information]. The blade chord length at the hub. The chord length of the blade at the rim;

[0114] The formula for calculating the rounded radius of the airfoil's leading edge is:

[0115]

[0116] In the formula, The blade chord length; both the impeller blades and guide vanes adopt the 791 airfoil design, and the trailing edge of the blades is thinned at a fixed ratio, with a trailing edge thickness of... ;;

[0117] Blade airfoil and profile optimization

[0118] The impeller blades adopt the 791 airfoil and the leading edge is rounded and optimized to suppress cavitation initiation and ensure a balance between blade aerodynamic performance and cavitation performance.

[0119] S5. Quantitative hydraulic design of the guide vane: Obtain the actual streamline lengths of the inlet, middle, and outlet sections within the guide vane flow channel; the guide vane airfoil chord length is positively correlated with this length and energy recovery efficiency, the guide vane rib radius is positively correlated with this chord length, and both are negatively correlated with the trigonometric function based on the inlet and outlet angle construction; the guide vane adopts the same 791 airfoil as the impeller with a fixed-proportion thinning of the trailing edge, specifically:

[0120] The guide vane design is based on the flow channel streamline and incorporates the concept of energy recovery to ensure that the kinetic energy of the fluid at the impeller outlet is efficiently converted into pressure energy.

[0121] Core parameter definitions and value criteria:

[0122] Streamline length: The actual length of the streamline at a certain cross section within the guide vane channel, extracted using flow field simulation software such as ANSYS CFX or NUMECA. The extracted cross section includes the inlet cross section, the intermediate cross section, and the outlet cross section to ensure the integrity of the streamline.

[0123] Airfoil chord length (L): The chord length of the guide vane blade, which is optimized in conjunction with the streamline length and the blade inlet and outlet angles;

[0124] Bone line radius (R): The radius of curvature of the guide vane blade bone line, which affects the smoothness of fluid diversion and energy loss;

[0125] Blade inlet angle ( ): The angle between the guide vane blade inlet rib line and the incoming flow direction is determined by the inlet axial surface velocity of the corresponding cross section;

[0126] Blade exit angle ( The angle between the guide vane blade outlet rib and the outflow direction directly affects the energy recovery efficiency.

[0127] Precise calculation of key parameters

[0128] Guide vane airfoil chord Calculation formula and radius of guide vane skelet in S53 The calculation formula is as follows:

[0129]

[0130]

[0131] In the formula, This is the actual length of the streamline at the corresponding cross section within the guide vane channel; For guide vane energy recovery efficiency, target value ; The angle between the guide vane blade inlet rib line and the incoming flow direction, with a value range of [value missing]. ; The guide vane blade exit angle, and the guide vane inlet, middle, and outlet cross sections. All values ;

[0132] Blade airfoil and structural optimization

[0133] The guide vane blades and impeller blades adopt the same 791 airfoil to ensure the consistency of fluid flow characteristics in the flow channel; at the same time, the trailing edge of the guide vane blades is thinned to reduce wake loss and pressure pulsation.

[0134] S6. Dynamic coupling matching between impeller and guide vane: Determine the overall range of the number of guide vane blades and allocate sub-ranges according to sub-intervals, constraining that the number of guide vane blades and the number of impeller blades are not multiples of each other and that the absolute value of the difference in number is not equal to 1. Specifically:

[0135] Dynamic matching design of impeller and guide vanes:

[0136] To achieve flow field coordination, reduce pressure pulsation, and avoid resonance, the number of guide vane blades... With the number of impeller blades Dynamic matching rules are used:

[0137] The number of guide vane blades should be between 5 and 10, for low specific speeds (700 < 1000 rpm). For speeds ≤900, take 8~10; for high specific speeds (1200 < When the speed is ≤1500, take 5~7; for medium specific speed (900 < When ≤1200), take values ​​of 6~8; Core constraint conditions:

[0138] The number of guide vane blades must not be a multiple of the number of impeller blades to avoid harmonic resonance;

[0139] satisfy ≠ ±1, to reduce mutual interference between blades;

[0140] When the number of impeller blades =3 (1000 < When ≤1500), the number of guide vane blades =7~8, the pressure pulsation amplitude is the smallest;

[0141] When the number of impeller blades =4 (700 < When ≤1000), the number of guide vane blades =9, the highest energy recovery efficiency;

[0142] Matching verification: The flow field coupling characteristics between the impeller and the guide vane are calculated through CFD simulation to ensure that the matching degree between the flow field at the impeller outlet and the flow field at the guide vane inlet is ≥90%.

[0143] Design verification method

[0144] To ensure the reliability of the design scheme, the following three levels of verification are required:

[0145] 1. Performance verification: The head, efficiency, and power under the design conditions are calculated through CFD simulation to ensure that the efficiency is ≥82% and there is no overload area (rated power ≤ motor rated power × 0.95).

[0146] 2. Cavitation resistance verification: Simulation calculations were performed using cavitation models (such as the Zwart-Gerber-Belamri model). ,make sure ≤Design allowable value × 0.85;

[0147] 3. Stability verification: The pressure pulsation amplitude (≤0.05MPa) was calculated by transient CFD simulation, and the vibration acceleration (≤2.5mm / s²) was verified by modal analysis.

[0148] The calculation formula for the impeller base diameter in S12 and the secondary correction formula in S13 are as follows, which together constitute the complete impeller diameter calculation. Calculation formula:

[0149]

[0150] In the formula, For design flow rate, the unit is ; for Eigenvalues; Motor speed, unit: ; This is the required net positive suction head (NPSH) under the design operating conditions. To allow for net positive suction head (NPSH);

[0151] The The specific range of values ​​is: when hour, Pick ;when hour, Pick ;

[0152] The guide vane airfoil chord length in S52 Calculation formula and radius of guide vane skelet in S53 The calculation formula is as follows:

[0153]

[0154]

[0155] In the formula, This is the actual length of the streamline at the corresponding cross section within the guide vane channel; For guide vane energy recovery efficiency, target value ; The angle between the guide vane blade inlet rib line and the incoming flow direction, with a value range of [value missing]. ; The guide vane blade exit angle, and the guide vane inlet, middle, and outlet cross sections. All values ;

[0156] It also includes the following parameter limitations:

[0157] Define hub ratio ,in The diameter of the wheel hub. The impeller diameter, the The following constraint formula must be satisfied:

[0158]

[0159] Define the density of the lattice as the chord length of the blade. Spacing between blades The ratio; The specific speed of the submersible axial flow pump is given by: The distance between adjacent blades on the same impeller along the same circumference is the arc length of the blades. The specific value range for this distance is as follows:

[0160] when At that time, the density of the blade cascade at the hub Blade density at the rim ;

[0161] when At that time, the density of the blade cascade at the hub Blade density at the rim ;

[0162] This also includes the following blade parameter limitations:

[0163] The formula for calculating the linearly gradual slope of blade thickness from the rim to the hub is:

[0164]

[0165] and ,in The thickness of the blades at the hub. The thickness of the blade at the rim is [missing information]. The blade chord length at the hub. The chord length of the blade at the rim;

[0166] The formula for calculating the rounded radius of the airfoil's leading edge is:

[0167]

[0168] In the formula, The blade chord length; both the impeller blades and guide vanes adopt the 791 airfoil design, and the trailing edge of the blades is thinned at a fixed ratio, with a trailing edge thickness of... ;

[0169] In summary, this invention establishes hierarchical constraints and linear correlation rules for hub ratio and blade density with specific speed by dividing the high specific speed range into sub-intervals. This breaks through the limitations of traditional model-to-analysis algorithms, can adapt to a wide range of high specific speed conditions, balances blade strength and flow channel unobstructedness, effectively suppresses flow field distortion and boundary layer separation, and improves operating efficiency under all conditions.

[0170] By using the impeller diameter precision calculation logic with cavitation risk compensation, a correction mechanism is built based on the difference between the required and allowable cavitation margin. While ensuring hydraulic performance, this effectively delays the initiation of cavitation, significantly improves the pump set's anti-cavitation performance, and extends the service life of the equipment.

[0171] By using the exclusive coupling constraint of the number of impeller and guide vane blades, the risk of harmonic resonance is avoided from the root, significantly reducing the pressure pulsation, vibration and noise of the pump unit, and solving the problem of poor operation stability caused by insufficient coupling in traditional design.

[0172] Through quantitative design of guide vane airfoil and bone line and refined optimization of 791 airfoil, the energy recovery efficiency of guide vane is maximized, flow loss and wake loss are reduced, the hydraulic efficiency of pump set is further improved, and long-term operating energy consumption is reduced.

[0173] This invention forms a complete and standardized hydraulic design system that can fully meet the core requirements of major water conservancy and municipal projects for efficient, stable, and low-noise operation of pump sets.

[0174] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump, wherein the high specific speed is defined as a specific speed within a preset range, and this range is divided into at least two sub-ranges according to the specific speed; the method is based on the coupling of lift method correction and streamline method to achieve the design, characterized in that: Includes the following steps: S1. Accurate calculation of impeller diameter: Obtain the design flow rate, motor speed and corresponding characteristic values, obtain the basic diameter based on the design flow rate and characteristic values, construct a compensation coefficient using the difference between the required and allowable net positive suction head (NPSH) to correct the basic diameter, and fine-tune it in combination with the standard motor speed. S2. Hub ratio graded optimization: The ratio of hub diameter to impeller diameter is set to increase as the specific speed decreases within the sub-interval, and its lower limit is a linear function with a constant term that is positively correlated with the specific speed. S3, Blade cascade density collaborative design: Set the ratio of the blade chord length to the distance between the arc lengths of adjacent blades in the same impeller within each sub-section to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub; S4. Blade integrated parameter design: The number of impeller blades is determined based on sub-intervals, and the blade natural frequency is verified by a preset multiple that is greater than the fluid excitation frequency. The blade thickness is set to increase linearly from the rim to the hub and the gradual slope is determined. The 791 airfoil is adopted and the leading edge is rounded off at a fixed ratio based on the chord length. S5. Quantitative hydraulic design of guide vanes: Obtain the actual streamline lengths of the three sections at the inlet, middle, and outlet of the guide vane flow channel; the guide vane airfoil chord length is positively correlated with this length and energy recovery efficiency, the guide vane skelet radius is positively correlated with this chord length, and both are negatively correlated with the trigonometric function based on the inlet and outlet angle construction; the guide vane adopts the same 791 airfoil as the impeller with a fixed tail edge thinning ratio; S6. Dynamic coupling matching between impeller and guide vane: Determine the overall range of the number of guide vane blades and allocate sub-ranges according to sub-intervals, constraining that the number of guide vane blades and impeller blades are not multiples of each other and that the absolute value of the difference in number is not equal to 1.

2. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 1, characterized in that: The precise calculation of the S1 impeller diameter specifically includes the following sub-steps: S11: Determine the corresponding characteristic value based on the preset high specific speed range of the submersible axial flow pump. The range of values ​​for; S12: Obtain Design Flow Combined with the aforementioned feature values The impeller base diameter is calculated. S13: Obtain the required net positive suction head (NPSH) and allowable NPSH under the design conditions. Based on the difference between the two, construct a cavitation risk compensation coefficient. Perform a secondary correction on the impeller base diameter and combine it with a reverse fine-tuning of the standard motor speed to obtain the final impeller diameter. .

3. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 2, characterized in that: The complete impeller diameter The calculation formula consists of multiplying the foundation diameter portion by the cavitation risk compensation portion; wherein, the foundation diameter portion is multiplied by the design flow rate. and eigenvalues The ratio is proportional to the specified root of the ratio; the cavitation risk compensation portion is composed of a constant 1 plus a value based on the required net positive suction head (NPSH). With allowable net positive suction head (NPSH) The difference and the allowable net positive suction head (NPSH) constitute the correction term; the cavitation risk compensation coefficient is based on the required NPSH. With allowable net positive suction head (NPSH) The difference is constructed, and the compensation coefficient is used to... A second correction is made to compensate for cavitation risks.

4. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 1, characterized in that: The S5 guide vane hydraulic quantitative design specifically includes the following sub-steps: S51: Extract the actual streamline lengths of the inlet, intermediate, and outlet sections within the guide vane channel. ; S52: Based on the actual length of the streamline Guide vane energy recovery efficiency and the inlet angle of the guide vane blades Exit Angle The guide vane airfoil chord length was calculated. ; S53: Based on the airfoil chord length of the guide vane and imported corner Exit Angle The radius of the guide vane rib is calculated. .

5. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 4, characterized in that: The guide vane airfoil chord Based on the actual length of the streamline With guide vane energy recovery efficiency The product of the two, divided by the inlet angle With exit angle The radius of the guide vane rib is calculated by taking the sine of half the sum of the two values. Based on the airfoil chord length Divide by the exit angle With the import angle The difference is calculated by a preset multiple of half the sine value.

6. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 1, characterized in that: The dynamic coupling and matching of the S6 impeller and guide vane specifically includes the following sub-steps: S61: Determine the number of guide vane blades based on the preset high specific speed range. The overall range of values, and the corresponding sub-ranges are assigned according to the specific speed sub-ranges; S62: Calculate the number of guide vane blades With the number of impeller blades The modulo operation results are used to verify that the two are not multiples of each other; S63: Calculate and The absolute value of the difference between the two is used to verify that the absolute value of the difference is not equal to 1, thus completing the exclusive coupling matching.

7. A hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 6, characterized in that: The and The optimal matching combination is: when the number of impeller blades At that time, the number of guide vane blades Choose 7 or 8; when the number of impeller blades At that time, the number of guide vane blades Take 9.

8. The hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 1, characterized in that: It also includes the following parameter limitations: defining the hub ratio. Hub diameter With impeller diameter The ratio, the The constraint to be satisfied is: the hub ratio Greater than or equal to based on specific speed A linear function relating the speed to a preset reference speed, wherein the linear function includes a positive proportional coefficient term and a constant compensation term; the blade cascade density is defined as the blade chord length. Spacing between blades The ratio of, where The distance between adjacent blades on the same impeller along the same circumference is the arc length of the blades. The specific value range for this distance is as follows: when At that time, the density of the blade cascade at the hub Blade density at the rim ; when At that time, the density of the blade cascade at the hub Blade density at the rim .

9. A hydraulic design method for coupling and matching impeller guide vanes of a high specific speed submersible axial flow pump according to claim 1, characterized in that: This also includes the following blade parameter constraints: the linear gradient slope of the blade thickness from the rim to the hub. This is the ratio of the difference in blade thickness between the hub and the rim to the difference in blade chord length between the hub and the rim. Leading edge rounding radius of the airfoil With the chord length of the blade They are in a fixed proportional relationship; both the impeller blades and guide vanes adopt the 791 airfoil shape, and the trailing edge of the blades is thinned in a fixed proportion, with a trailing edge thickness of... Length of the leaf chord Multiply by the preset trailing edge thinning ratio constant.

10. A hydraulic design system for impeller-guide vane coupling matching of a high specific speed submersible axial flow pump according to claim 1, wherein the high specific speed is defined as the specific speed of the submersible axial flow pump being within a preset high specific speed range, the preset high specific speed range being divided into at least two sub-ranges according to the magnitude of the specific speed, and the system realizing the hydraulic design of the impeller and guide vane based on lift method correction and streamline method coupling, characterized in that: The system includes: Impeller diameter precision calculation module: used to obtain the design flow rate and motor speed, determine the characteristic value of the corresponding high specific speed range; based on the design flow rate and characteristic value, the impeller base diameter is obtained, and the cavitation risk compensation coefficient is constructed by using the difference between the required net positive suction head (NPSH) and the allowable NPSH under the design conditions, and the impeller base diameter is corrected in the second way, and fine-tuned in the reverse direction in combination with the standard motor speed; Hub ratio grading optimization module: used to set the ratio of hub diameter to impeller diameter to increase as the specific speed decreases within the sub-interval, and the lower limit of this ratio is a linear function with a constant term that is positively correlated with the specific speed. Blade density collaborative design module: used to set the ratio of blade chord length to arc length spacing in each sub-interval to increase as the specific speed decreases, and the ratio at the rim is not less than the preset percentage at the hub; Blade integrated parameter design module: used to determine the number of impeller blades based on specific speed sub-range, and to perform resonance verification with the blade natural frequency being greater than a preset multiple of the fluid excitation frequency; to set the blade thickness to increase linearly from the rim to the hub along the chord length direction, and to determine its thickness linear gradient slope; to use the 791 airfoil as the impeller blade cross-sectional shape, and to perform fixed-proportion rounding optimization on the airfoil leading edge based on the blade chord length; Guide vane hydraulic quantitative design module: used to obtain the actual streamline lengths of the inlet, middle and outlet sections in the guide vane flow channel; to make the guide vane airfoil chord length positively correlated with the actual streamline lengths of the three sections in the flow channel and the energy recovery efficiency, and the guide vane skelet radius positively correlated with the chord length, and both negatively correlated with the trigonometric function based on the inlet and outlet angle construction; using the same 791 airfoil as the impeller with a fixed tail edge thinning ratio as the guide vane blade; Impeller and guide vane dynamic coupling matching module: used to determine the overall range of the number of guide vane blades and allocate corresponding sub-ranges according to different specific speed sub-ranges; execute exclusive coupling matching constraints, that is, the number of guide vane blades and the number of impeller blades are not multiples of each other, and the absolute value of the difference between the two is not equal to 1.

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