Quick prediction method of force of single nozzle of impulse water turbine at different opening degree based on momentum performance mapping

Abstract

This application relates to a rapid prediction method for the force of a single nozzle of an impulse turbine at different opening degrees based on momentum-efficiency mapping. The method includes: constructing momentum response functions for each opening degree. 、 Scale viscous response function 、 Bucket Steering Response Function 、 The jet jet response function is matched to determine the combination of response functions for the impulse turbine. Based on the combination of response functions, the momentum efficiency coefficient of the impulse turbine is calculated to determine the single-nozzle force prediction formula. Based on the single-nozzle force prediction formula, the unit geometry parameters of the impulse turbine, and the operating head and flow rate, the single-nozzle predicted force of the impulse turbine at different opening degrees is predicted. This solves the problems in related technologies, such as high computational cost and complex parameter tuning in three-dimensional unsteady computational fluid dynamics simulation, the lack of a unified physical framework for empirical formulas or correction methods, and limited prediction accuracy. Therefore, it provides technical support for nozzle opening optimization, operational stability assessment, and structural design.

Description

Technical Field

[0001] This application relates to the field of water turbine engineering technology, and in particular to a method for rapid prediction of the force of a single nozzle at different opening degrees of an impulse water turbine based on momentum efficiency mapping. Background Technology

[0002] Impulse turbines are widely used in ultra-high head hydropower projects. The interaction between their nozzles and water buckets directly determines the mechanical load characteristics and operational stability of the unit. In engineering practice, the unit often adopts a single-nozzle operation mode under scenarios such as low-load operation and peak-shaving start-up and shutdown. The force characteristics under different nozzle openings become the core parameters affecting vibration response and life prediction.

[0003] In related technologies, two main methods are used to obtain the force of a single nozzle. One method is to conduct three-dimensional unsteady computational fluid dynamics simulation and obtain the force by numerically solving the flow field details. The other method is to use empirical formulas or correction methods to solve the force based on specific working condition data.

[0004] However, in related technologies, the high cost and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulation make it unsuitable for rapid engineering iterations. Empirical formulas or correction methods are only applicable to specific working conditions, lack a unified physical framework, and have limited prediction accuracy, resulting in an inability to balance computational efficiency and accuracy, which urgently needs improvement. Summary of the Invention

[0005] This application provides a method for rapid prediction of the force of a single nozzle at different opening degrees in an impulse turbine based on momentum efficiency mapping. This method addresses the problem in related technologies where the high cost and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulation make it unsuitable for rapid engineering iterations. Empirical formulas or correction methods are only applicable to specific working conditions, lack a unified physical framework, and have limited prediction accuracy, thus failing to balance computational efficiency and accuracy.

[0006] This application provides a method for rapid prediction of the force acting on a single nozzle of an impulse turbine at different opening degrees based on momentum-efficiency mapping, including the following steps: constructing the momentum response function at each opening degree. 、 Scale viscous response function 、 Bucket Steering Response Function 、 A jet matching response function is used to determine the combination of response functions of the impulse turbine based on the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function. The momentum efficiency coefficient of the impulse turbine is calculated based on the combination of response functions, and a single-nozzle force prediction formula is determined based on the momentum efficiency coefficient. Based on the single-nozzle force prediction formula, the unit geometric parameters of the impulse turbine, and the operating head and flow rate, the predicted single-nozzle force of the impulse turbine at different opening degrees is predicted.

[0007] Optionally, in one embodiment of this application, the construction of the opening momentum response function is performed separately. 、 Scale viscous response function 、 Bucket Steering Response Function 、 The jet matching response function includes: constructing the nozzle opening momentum response function based on the influence of the nozzle opening of the impulse turbine on the jet flow transfer efficiency; constructing the scale viscosity response function based on the regulating effect of the jet Reynolds number of the impulse turbine on viscous loss; constructing the bucket face steering response function based on the influence of the bucket splitting angle and circumferential velocity ratio of the impulse turbine on the flow steering efficiency; and constructing the jet matching response function based on the adaptability between the jet width of the impulse turbine and the effective contact width of the bucket.

[0008] Optionally, in one embodiment of this application, the step of calculating the momentum efficiency coefficient of the impulse turbine based on the response function combination includes: determining the influence of the nozzle opening, the jet Reynolds number, the circumferential velocity ratio, and the adaptability on the momentum transfer efficiency of the impulse turbine according to the response function combination; and multiplying the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function based on the influence to calculate the momentum efficiency coefficient.

[0009] Optionally, in one embodiment of this application, the momentum efficiency coefficient is calculated as follows: , in, η F The momentum efficiency coefficient is mentioned above. F α Let be the opening momentum response function. F β The scale-dependent viscous response function is given. F γ Let be the bucket steering response function. F μ Let be the jet matching response function.

[0010] Optionally, in one embodiment of this application, the force prediction formula is: , in, F pred The predicted result of the single nozzle force. ρ For the density of water, Q For the traffic, V j For jet velocity, ηF The momentum efficiency coefficient is given.

[0011] This application's embodiments can introduce an opening momentum response function, a scale viscosity response function, a bucket face steering response function, and a jet matching response function, and combine these four functions to form a momentum efficiency coefficient. This corrects the theoretical momentum expression, enabling rapid prediction of the force exerted by a single nozzle at different opening degrees. Based on a unified momentum efficiency mapping framework, it explicitly quantifies the effects of opening degree, viscosity, steering, and jet matching, maintaining prediction accuracy across a small to full opening range. This enhances the physical interpretability of the prediction, significantly reduces computational costs, facilitates rapid use in the design phase and operational optimization, and possesses good engineering versatility, providing technical support for nozzle opening optimization, operational stability assessment, and structural design. Therefore, it solves the problems in related technologies, such as the high computational cost and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulation, unsuitability for rapid engineering iteration, the limitation of empirical formulas or correction methods to specific working conditions, the lack of a unified physical framework, and limited prediction accuracy, which result in an inability to balance computational efficiency and accuracy.

[0012] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0013] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a method for rapid prediction of the force of a single nozzle of an impulse turbine at different opening degrees based on momentum efficiency mapping, according to an embodiment of this application. Figure 2 This is a schematic diagram of a single-nozzle impulse turbine according to an embodiment of this application; Figure 3 This is a graph showing the change of nozzle opening momentum response function with nozzle opening according to an embodiment of this application; Figure 4 This is a comparison chart of the prediction results and high-precision numerical simulation results of a single nozzle at different opening degrees according to an embodiment of this application. Detailed Implementation

[0014] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0015] The following describes, with reference to the accompanying drawings, a method for rapid prediction of the force of a single nozzle at different opening degrees of an impulse turbine based on momentum efficiency mapping, according to an embodiment of this application. In response to the aforementioned background technologies, the high computational cost and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulation make it unsuitable for rapid engineering iterations. Empirical formulas or correction methods are only applicable to specific working conditions, lack a unified physical framework, and have limited prediction accuracy, resulting in an inability to balance computational efficiency and accuracy. This application provides a rapid prediction method for the force of a single nozzle at different opening degrees in an impulse turbine based on momentum efficiency mapping. In this method, the opening momentum response function, scale viscosity response function, bucket face steering response function, and jet matching response function can be introduced. These four functions are combined to form a momentum efficiency coefficient, which corrects the theoretical momentum expression, enabling rapid prediction of the force of a single nozzle at different opening degrees. Based on a unified momentum efficiency mapping framework, the effects of opening degree, viscosity, steering, and jet matching are explicitly quantified. This maintains prediction accuracy across the range from small to full opening degrees, enhances the physical interpretability of the prediction, significantly reduces computational costs, facilitates rapid use in the design phase and operational optimization, and has good engineering versatility. It can provide technical support for nozzle opening optimization, operational stability assessment, and structural design. This solves the problems in related technologies, such as the high cost and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulation, which makes it unsuitable for rapid engineering iterations, the fact that empirical formulas or correction methods are only applicable to specific working conditions, the lack of a unified physical framework, and the limited prediction accuracy, which makes it impossible to balance computational efficiency and accuracy.

[0016] Specifically, Figure 1 This is a flowchart illustrating a method for rapid prediction of the force of a single nozzle at different opening degrees in an impulse turbine based on momentum efficiency mapping, as provided in an embodiment of this application.

[0017] like Figure 1 As shown, the rapid prediction method for the force of a single nozzle at different opening degrees of an impulse turbine based on momentum efficiency mapping includes the following steps: In step S101, the opening momentum response function is constructed respectively. 、 Scale viscous response function 、 Bucket Steering Response Function 、 The jet matching response function is used to determine the combination of response functions of the impulse turbine based on the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function.

[0018] Optionally, in one embodiment of this application, aperture momentum response functions are constructed respectively. 、 Scale viscous response function 、 Bucket Steering Response Function 、The jet matching response function includes: constructing an opening momentum response function based on the influence of the nozzle opening of the impulse turbine on the jet flow transfer efficiency; constructing a scale viscosity response function based on the regulating effect of the jet Reynolds number of the impulse turbine on viscous loss; constructing a bucket face steering response function based on the influence of the bucket splitting angle and circumferential velocity ratio of the impulse turbine on the flow steering efficiency; and constructing a jet matching response function based on the adaptability between the jet width of the impulse turbine and the effective contact width of the bucket.

[0019] Specifically, embodiments of this application can construct an aperture momentum response function. F α Used to characterize the relative opening of the nozzle α The effect on jet momentum transfer efficiency, where the aperture momentum response function is: , in, k 1. k 2. k 3 represents the parameters of the opening momentum response function. The preferred parameter range is: k 1∈[0.95, 1.00], k 2∈[-0.05, 0.02], k 3∈[-0.02, 0.01].

[0020] Constructing the scale-viscous response function F β Used to characterize the Reynolds number of a jet. Re The moderating effect on viscous loss, wherein the scale viscous response function is: , Among them, the scale viscosity response function is related to the jet Reynolds number. D n The jet diameter under rated operating conditions, ν For kinematic viscosity, c 1 and c 2 represents the parameters of the scale-dependent viscous response function. Preferred parameter range: c 1∈[0.01, 0.05], c 2∈[0.10, 0.30].

[0021] Constructing the bucket steering response function F γ Used to characterize the water bucket splitting angle β and circumferential speed ratio u / V j The impact on flow turning efficiency, where the bucket face turning response function is: , Among them, the bucket steering response function is related to the split angle and the circumferential velocity ratio. β For the water bucket diversion angle, u The circumferential velocity at the water bucket joint circle, r 0 is the optimal circumferential speed ratio. m 1. r 0 represents a parameter of the bucket steering response function. The preferred parameter range is: m 1∈[0.1, 0.3], r 0∈[0.45, 0.50].

[0022] Constructing the jet matching response function F μ This is used to characterize the fit between the jet width and the effective contact width of the water bucket, where the jet matching response function is: , The jet matching response function is related to both the jet width and the water bucket contact width. B j The nozzle jet width, B b The effective contact width of the water bucket, p 1 and p 2 represents the parameters of the jet matching response function, and the preferred parameter range is: p 1∈[0.05, 0.15], p 2∈[0.03, 1.0]. The combination of response functions for the impulse turbine is determined based on the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function.

[0023] Among them, parameters k 1. k 2. k 3. c 1. c 2. m 1. r 0、 p 1. p Both values ​​were obtained through numerical simulation calibration or experimental regression, and adjusted according to different operating conditions to ensure prediction accuracy. This application's embodiment only requires one calibration during the R&D phase using existing experimental or limited numerical calculation data, and can be directly applied to predict different opening conditions of similar impulse turbines, eliminating the need for repeated large-scale numerical simulation calculations or system tests in engineering applications. This calibration method ensures both the physical rationality and reproducibility of the parameters, and makes this application's embodiment fast and scalable in engineering practice.

[0024] In step S102, the momentum efficiency coefficient of the impulse turbine is calculated based on the response function combination, so as to determine the single nozzle force prediction formula according to the momentum efficiency coefficient.

[0025] Optionally, in one embodiment of this application, the momentum efficiency coefficient of the impulse turbine is calculated based on the combination of response functions, including: determining the influence of nozzle opening, jet Reynolds number, circumferential velocity ratio, and adaptability on the momentum transfer efficiency of the impulse turbine according to the combination of response functions; and multiplying the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function based on the influence to calculate the momentum efficiency coefficient.

[0026] The embodiments of this application can characterize the effects of nozzle opening, Reynolds number, bucket geometry and circumferential velocity ratio, and jet matching on momentum transfer efficiency based on the opening momentum response function, scale viscosity response function, bucket face turning response function, and jet matching response function, respectively, and combine the four functions to form a momentum efficiency coefficient.

[0027] Optionally, in one embodiment of this application, the momentum efficiency coefficient is calculated as follows: , in, η F The momentum efficiency coefficient, F α Let be the opening momentum response function. F β For scale-dependent viscous response function, F γ For the bucket steering response function, F μ This is the jet matching response function.

[0028] Furthermore, embodiments of this application can... η F A formula for predicting the force of a single nozzle is introduced.

[0029] Optionally, in one embodiment of this application, the force prediction formula is: , in, F pred This is the predicted result of the force applied by a single nozzle. ρ For the density of water, Q For traffic, V j For jet velocity, η F This is the momentum efficiency coefficient.

[0030] In step S103, based on the single-nozzle force prediction formula, the unit geometric parameters of the impulse turbine, and the operating head and flow rate, the single-nozzle predicted force of the impulse turbine at different opening degrees is predicted.

[0031] The embodiments of this application can combine unit geometric parameters and operating head. H With traffic Q It outputs the predicted force of a single nozzle at different opening degrees, which can be used for engineering design, operation optimization and stability assessment.

[0032] This application proposes a unified momentum-efficiency mapping framework that explicitly quantifies the effects of nozzle opening, viscosity, steering, and jet matching, enhancing the physical interpretability of predictions. The prediction formula adaptively adjusts with the nozzle opening, making it applicable to single-nozzle operating conditions from small to full opening. It maintains high accuracy in most operating conditions (typical error is generally less than 5%, and deviation is less than 1% under rated operating conditions), meeting engineering accuracy requirements. Compared to unsteady numerical simulation calculations, it significantly reduces computational costs and facilitates rapid use in the design phase and operational optimization. Unlike empirical formulas, the "momentum-efficiency mapping" method proposed in this application does not modify a single operating condition or local factor. Instead, it establishes a unified momentum correction framework through the organic combination of four types of response functions: opening, viscosity, steering, and jet matching. This framework not only maintains prediction accuracy within the range of small to full opening, but each response function also has a clear physical interpretation, systematically reflecting different mechanisms in nozzle-water bucket interactions, thus avoiding the "black box fitting" problem. It also has good engineering versatility and can provide technical support for nozzle opening optimization, operational stability assessment, and structural design.

[0033] Specifically, it can be combined with Figures 2 to 4 As shown, a specific embodiment is used to elaborate in detail the working principle of the method for rapid prediction of the force of a single nozzle of an impulse turbine at different opening degrees based on momentum efficiency mapping in the embodiments of this application.

[0034] like Figure 2 As shown, in a typical large high-head impulse turbine, the rated speed is 375 r / min, the rated head is 595 m, and the nozzle diameter is... D n =0.175m, number of water buckets is Z =21, water viscosity ν =1.0×10 -6 m² / s, nozzle opening under rated operating conditions α =0.75, Pitch circle diameter of the runner D =2.63m, water bucket splitting angle β The angle is 73°, and the ratio of the nozzle jet width to the effective contact width of the water bucket is... B j / B b ≈0.92. For example... Figure 3 As shown, the opening momentum response function F α Curve showing the change in nozzle opening, with the horizontal axis representing the nozzle opening. α The vertical axis represents the opening momentum response function. F α .

[0035] Based on the calibration results, the parameter values ​​can be: k 1 = 0.981, k 2 = 0.012, k 3 = -0.008; c 1 = 0.246, c 2 = 0.15; m 1 = 0.15, r 0 = 0.47; p 1 = 0.12, p 2 = 0.038.

[0036] Under the above calculation conditions, we get: F α ≈0.985, F β ≈0.981, F γ ≈0.955, F μ ≈0.989, η F ≈0.914.

[0037] Substituting into the formula yields the predicted force for a single nozzle at different opening degrees, such as... Figure 4 As shown, the horizontal axis represents the nozzle opening. α The vertical axis represents the force applied by a single nozzle, maintaining high accuracy under operating conditions from 0.3 opening to full opening (typical error is generally less than 5%, and deviation is less than 1% under rated operating conditions), meeting engineering accuracy requirements.

[0038] The method for rapid prediction of the force of a single nozzle at different opening degrees in an impulse turbine based on momentum efficiency mapping proposed in this application introduces an opening momentum response function, a scale viscosity response function, a bucket face steering response function, and a jet matching response function. These four functions are combined to form a momentum efficiency coefficient, which modifies the theoretical momentum expression, enabling rapid prediction of the force of a single nozzle at different opening degrees. Based on a unified momentum efficiency mapping framework, the effects of opening degree, viscosity, steering, and jet matching are explicitly quantified. This maintains prediction accuracy across a range from small to full opening degrees, enhances the physical interpretability of the prediction, significantly reduces computational costs, facilitates rapid use in the design phase and operational optimization, and possesses good engineering versatility, providing technical support for nozzle opening optimization, operational stability assessment, and structural design. This solves the problem in related technologies where high computational costs and complex parameter tuning of three-dimensional unsteady computational fluid dynamics simulations make them unsuitable for rapid engineering iterations; empirical formulas or correction methods are only applicable to specific operating conditions; a unified physical framework is lacking; and prediction accuracy is limited, resulting in an inability to balance computational efficiency and accuracy.

[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0042] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0043] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0044] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0045] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0046] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for rapid prediction of the force acting on a single nozzle at different opening degrees in an impulse turbine based on momentum-efficiency mapping, characterized in that, Includes the following steps: Construct the opening momentum response function respectively 、 Scale viscous response function 、 Bucket Steering Response Function 、 The jet matching response function is used to determine the combination of response functions of the impulse turbine based on the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function. The momentum efficiency coefficient of the impulse turbine is calculated based on the combination of the response functions, and the single nozzle force prediction formula is determined based on the momentum efficiency coefficient. Based on the single-nozzle force prediction formula, the unit geometric parameters of the impulse turbine, and the operating head and flow rate, the single-nozzle predicted force of the impulse turbine at different opening degrees is predicted.

2. The method according to claim 1, characterized in that, The respective construction of the opening momentum response function 、 Scale viscous response function 、 Bucket Steering Response Function 、 The jet matching response function includes: Based on the influence of the nozzle opening of the impulse turbine on the jet momentum transfer efficiency, the opening momentum response function is constructed. Based on the effect of the jet Reynolds number of the aforementioned impulse turbine on the regulation of viscous loss, the scale viscous response function is constructed. Based on the influence of the bucket splitting angle and circumferential velocity ratio of the aforementioned impulse turbine on the flow steering efficiency, the bucket surface steering response function is constructed. Based on the compatibility between the jet width of the impingement turbine and the effective contact width of the water bucket, the jet matching response function is constructed.

3. The method according to claim 2, characterized in that, The calculation of the momentum efficiency coefficient of the impulse turbine based on the combination of the response functions includes: The effects of the nozzle opening, the jet Reynolds number, the circumferential velocity ratio, and the adaptability on the momentum transfer efficiency of the impulse turbine are determined based on the combination of the response functions. Based on the aforementioned influence, the opening momentum response function, the scale viscosity response function, the bucket face steering response function, and the jet matching response function are multiplied together to calculate the momentum efficiency coefficient.

4. The method according to claim 1, characterized in that, The formula for calculating the momentum efficiency coefficient is: ， in, η F The momentum efficiency coefficient is mentioned above. F α Let be the opening momentum response function. F β The scale-dependent viscous response function is given. F γ Let be the bucket steering response function. F μ Let be the jet matching response function.

5. The method according to claim 1, characterized in that, The force prediction formula is as follows: ， in, F pred The predicted result of the single nozzle force. ρ For the density of water, Q For the traffic, V j For jet velocity, η F The momentum efficiency coefficient is given.

Images