Rapid numerical prediction method and system for flow-induced noise of hydraulic machinery

Abstract

The invention discloses a rapid numerical prediction method and system for flow-induced noise of a hydraulic machine, and relates to the technical field of computer numerical simulation, and the method comprises the following steps: obtaining external characteristic test data of the hydraulic machine; establishing a fluid domain model of the hydraulic machinery, dividing a structural grid, and performing steady numerical simulation under different working conditions; comparing a steady numerical simulation result with a test result; after the result of the unsteady numerical simulation calculation is converged, drawing a time domain curve graph of the sound pressure level of the flow-induced noise; and obtaining flow induced noise sound pressure level frequency domain data through calculation. According to the noise prediction result obtained through the method, the number of tests of low-noise design of the hydraulic machinery can be reduced, the research and development period can be shortened, the research and development cost can be reduced, the design efficiency can be greatly improved, and in addition, the characteristics and mechanisms of flow-induced noise of the hydraulic machinery can be researched and revealed according to the prediction result.

Description

Technical Field

[0001] The invention relates to the technical field of computer numerical simulation, and in particular to a method and system for rapid numerical prediction of flow-induced noise of hydraulic machinery. Background Art

[0002] Hydraulic machinery (such as pumps, turbines, propellers, etc.) plays an important role in the fields of fluid transportation such as water conservancy, aerospace, and shipbuilding, and is a strategic equipment related to the national economy, people's livelihood, and national security. In the actual operation of hydraulic machinery, flow-induced noise will be generated due to turbulent flow, the interaction between fluid and flow-through components, and cavitation. For example, the flow-induced noise generated by the units in pumping stations and hydropower stations will have an impact on people's physical and mental health. In severe cases, the vibration caused by the noise will cause equipment damage or even accidents; the flow-induced noise generated by centrifugal pumps and propellers in military fields such as ships and submarines greatly increases their probability of exposure and being hit, seriously affecting their survivability and combat effectiveness. Therefore, the problem of flow-induced noise in hydraulic machinery should not be underestimated.

[0003] The numerical simulation method of flow-induced noise of hydraulic machinery has gradually matured. The current mainstream method is to first solve the flow field based on commercial CFD software, and then import the flow field information into commercial acoustic software to solve the acoustic field. Although this method has high calculation accuracy, it consumes a lot of computing time and computing resources because it uses two commercial software and is divided into two stages of calculation, especially for hydraulic machinery with complex three-dimensional flow fields. Therefore, it is an urgent practical problem to build a fast and accurate numerical prediction method for flow-induced noise of hydraulic machinery, which has important academic value and engineering significance for studying the characteristics and mechanism of flow-induced noise of hydraulic machinery. Summary of the invention

[0004] In view of the problems existing in the existing rapid numerical prediction and system of flow-induced noise of hydraulic machinery, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is that a large amount of computing time and computing resources will be consumed.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a method for rapid numerical prediction of flow-induced noise of hydraulic machinery, which comprises the following steps:

[0008] Obtain external characteristic test data of hydraulic machinery;

[0009] Establish the fluid domain model of hydraulic machinery and divide the structural grid to perform steady-state numerical simulation under different working conditions;

[0010] Compare the steady-state numerical simulation results with the experimental results;

[0011] After the unsteady numerical simulation results converge, draw the time domain curve of the flow-induced noise sound pressure level;

[0012] The frequency domain data of flow-induced noise sound pressure level are obtained by calculation.

[0013] As a preferred solution of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery described in the present invention, the external characteristic test data includes head, efficiency and shaft power.

[0014] As a preferred embodiment of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery of the present invention, the step of performing steady numerical simulation under different working conditions comprises:

[0015] Set the boundary conditions of numerical simulation according to the external characteristic test;

[0016] Turbulence models are used to predict flow around and rotating flows near walls;

[0017] Through the prediction results, the steady-state values ​​under different working conditions are obtained.

[0018] As a preferred embodiment of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery of the present invention, the step of comparing the steady-state numerical simulation results with the test results comprises:

[0019] When the error between the constant numerical simulation result and the test result is greater than 5%, the fluid domain model of the hydraulic machinery is re-established and the structural grid is divided;

[0020] When the error between the steady numerical simulation results and the test results is no more than 5%, the steady numerical simulation results are used as the initial conditions to carry out unsteady numerical simulations under different working conditions, and the sound pressure level of the flow-induced noise of the hydraulic machinery at different times is solved.

[0021] As a preferred solution of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery of the present invention, the steps of solving the sound pressure level of flow-induced noise of hydraulic machinery at different times include:

[0022] Set X rotation cycles, the time is not as long as 1 / n;

[0023] Write the calculation formula for solving the sound pressure level using CEL language;

[0024] The calculation formula is expressed as:

[0025]

[0026] Where, L pIt is expressed as sound pressure level, which is the actual sound pressure P relative to the reference sound pressure P 0 The logarithmic form of the ratio.

[0027] As a preferred embodiment of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery of the present invention, the step of drawing a time domain curve diagram of the sound pressure level of flow-induced noise comprises:

[0028] The flow-induced noise sound pressure level in the last Y stable rotation periods is derived in the solver as a support for flow-induced noise data processing, and different cross sections are made to obtain time domain curves;

[0029] The time domain curve diagram is used to view the sound pressure level cloud diagram of the flow field at different positions and at different times, and to study the characteristics and laws of the sound field.

[0030] As a preferred solution of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery of the present invention, the method for obtaining frequency domain data of sound pressure level of flow-induced noise includes:

[0031] According to the A weighted calculation formula, the formula is expressed as:

[0032]

[0033] In the formula, Laeq represents the equivalent continuous sound pressure level, T represents time, p(t) represents instantaneous sound pressure, and A is the weighted value of the sound pressure level;

[0034] Write the code of A-weighted correction algorithm to correct the obtained sound pressure level frequency domain data to obtain the corrected flow-induced noise sound pressure level frequency domain data;

[0035] The frequency domain data obtained by A-weighted correction is subjected to iFFT transformation to obtain the corrected time domain data of the flow induced noise sound pressure level, thereby drawing the corrected time domain curve of the flow induced noise sound pressure level.

[0036] In a second aspect, an embodiment of the present invention provides a rapid numerical prediction system for flow-induced noise of hydraulic machinery, which includes a data acquisition module, a numerical simulation module, a result comparison module, and a data processing visualization module;

[0037] The data acquisition module is used to acquire the external characteristic test data of the hydraulic machinery, including head, efficiency, and shaft power;

[0038] The numerical simulation module is used to establish a fluid domain model of hydraulic machinery and perform steady and unsteady numerical simulations;

[0039] The result comparison module is used to compare the numerical simulation results with the test results to evaluate the accuracy of the simulation;

[0040] The data processing and visualization module is used to derive the flow-induced noise sound pressure level data within a stable rotation period and draw a time domain curve graph.

[0041] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the processor executes the computer program, it implements any step of the above-mentioned method for rapid numerical prediction of flow-induced noise of hydraulic machinery.

[0042] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of the above-mentioned method for rapid numerical prediction of flow-induced noise of hydraulic machinery is implemented.

[0043] The beneficial effects of the present invention are as follows: based on the LES model, the sound pressure level data of the flow-induced noise is directly solved, and a program is written to process the data, so that the noise prediction results can be obtained quickly and accurately. Compared with the traditional noise numerical simulation method, a large amount of computing time and computing resources are saved, thereby improving the overall accuracy and speed of solving the flow-induced noise of hydraulic machinery. In addition, applying the noise prediction results to the low-noise hydraulic design of hydraulic machinery can reduce the number of tests, shorten the research and development cycle, save research and development costs, and thus improve the design efficiency of hydraulic machinery. On the other hand, the flow field data obtained by solving the LES model can be used to deeply study and reveal the complex internal flow mechanism of hydraulic machinery, providing theoretical support for the design and optimization of hydraulic machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0045] Figure 1 Flow chart of the fast numerical prediction method for flow-induced noise of hydraulic machinery. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0049] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0050] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] Reference Figure 1 , CFD is computational fluid dynamics (CFD); LES is large eddy simulation (LES); CFD-POST is post-processing of computational fluid dynamics, Python has no corresponding Chinese; FFT is Fourier transform; iFFT is inverse Fourier transform.

[0053] Example 1

[0054] Reference Figure 1, which is the first embodiment of the present invention, provides a method for rapid numerical prediction of flow-induced noise of hydraulic machinery, comprising the following steps:

[0055] S1. Obtain the external characteristic test data of hydraulic machinery.

[0056] The external characteristic test data include head, efficiency, shaft power

[0057] S2. Establish the fluid domain model of hydraulic machinery and divide the structural grid to perform steady-state numerical simulation under different working conditions.

[0058] The steps for steady-state numerical simulation under different working conditions include:

[0059] Set the boundary conditions of numerical simulation according to the external characteristic test;

[0060] Such as the inlet pressure (1atm) of the computational domain, the outlet mass flow rate, the rotation speed, the connection method of the dynamic and static interface, etc.;

[0061] Turbulence models are used to predict flow around and rotating flows near walls;

[0062] Through the prediction results, the steady-state values ​​under different working conditions are obtained.

[0063] Numerical simulation can provide accurate predictions of fluid flow behavior, including flow velocity, pressure distribution, etc., which are difficult to measure directly in experiments.

[0064] S3. Compare the steady-state numerical simulation results with the experimental results.

[0065] The steps for comparing the steady-state numerical simulation results with the experimental results include:

[0066] When the error between the constant numerical simulation result and the test result is greater than 5%, the fluid domain model of the hydraulic machinery is re-established and the structural grid is divided;

[0067] Used to modify related sections, such as: the accuracy of 3D modeling, the rationality of mesh division, the setting of boundary conditions, the selection of turbulence model, etc.

[0068] When the error between the steady-state numerical simulation result and the test result is no more than 5%, the steady-state numerical simulation result is used as the initial condition to carry out the unsteady numerical simulation under different working conditions, and solve the flow-induced noise sound pressure level of the hydraulic machinery at different times;

[0069] The steps to solve the flow-induced noise sound pressure level of hydraulic machinery at different times include:

[0070] Set X rotation cycles, the time is not as long as 1 / n;

[0071] Write the calculation formula for solving the sound pressure level using CEL language;

[0072] The calculation formula is expressed as:

[0073]

[0074] Where, L p It is expressed as sound pressure level, which is the actual sound pressure P relative to the reference sound pressure P 0 The logarithmic form of the ratio of

[0075] In this embodiment, 25 rotation cycles can be set.

[0076] S4. After the unsteady numerical simulation calculation results converge, draw the time domain curve of the flow-induced noise sound pressure level.

[0077] The steps of plotting a time domain graph of flow induced noise sound pressure level include:

[0078] The flow-induced noise sound pressure level in the last Y stable rotation periods is derived in the solver as a support for flow-induced noise data processing, and different cross sections are made to obtain time domain curves;

[0079] The time domain curve diagram is used to view the sound pressure level cloud diagram of the flow field at different positions and at different times, and to study the characteristics and laws of the sound field.

[0080] In this embodiment, the last 15 stable rotations are derived.

[0081] S5. Obtain the frequency domain data of the flow-induced noise sound pressure level by calculation.

[0082] Based on the flow-induced noise sound pressure level of 15 stable rotation cycles, we first wrote a code about the change of sound pressure level with time to obtain the time domain curve of the sound pressure level; secondly, we wrote an FFT (fast Fourier transform) code to process the time domain data of the sound pressure level, so as to obtain the frequency domain curve of the flow-induced noise sound pressure level.

[0083] The method for obtaining the frequency domain data of flow-induced noise sound pressure level includes:

[0084] According to the A weighted calculation formula, the formula is expressed as:

[0085]

[0086] In the formula, Laeq represents the equivalent continuous sound pressure level, T represents time, p(t) represents instantaneous sound pressure, and A is the weighted value of the sound pressure level;

[0087] Write the code of A-weighted correction algorithm to correct the obtained sound pressure level frequency domain data to obtain the corrected flow-induced noise sound pressure level frequency domain data;

[0088] Write iFFT (Inverse Fast Fourier Transform) code, perform iFFT transformation on the frequency domain data obtained by A-weighted correction, and obtain the corrected flow-induced noise sound pressure level time domain data, so as to draw the corrected flow-induced noise sound pressure level time domain curve.

[0089] In summary, based on the LES model, the sound pressure level data of flow-induced noise is directly solved, and a program is written to process the data, which can quickly and accurately obtain the noise prediction results. Compared with the traditional noise numerical simulation method, it saves a lot of computing time and computing resources, thereby improving the accuracy and speed of solving the flow-induced noise of hydraulic machinery as a whole. In addition, applying the noise prediction results to the low-noise hydraulic design of hydraulic machinery can reduce the number of tests, shorten the R&D cycle, save R&D costs, and thus improve the design efficiency of hydraulic machinery. On the other hand, the flow field data obtained by solving the LES model can deeply study and reveal the complex internal flow mechanism of hydraulic machinery, and provide theoretical support for the design and optimization of hydraulic machinery.

[0090] Example 2

[0091] On the basis of the first embodiment, this embodiment further provides a rapid numerical prediction system for flow-induced noise of hydraulic machinery, including a data acquisition module, a numerical simulation module, a result comparison module, and a data processing visualization module;

[0092] The data acquisition module is used to acquire the external characteristic test data of the hydraulic machinery, including head, efficiency, and shaft power;

[0093] The numerical simulation module is used to establish a fluid domain model of hydraulic machinery and perform steady and unsteady numerical simulations;

[0094] The result comparison module is used to compare the numerical simulation results with the test results to evaluate the accuracy of the simulation;

[0095] The data processing and visualization module is used to derive the flow-induced noise sound pressure level data within a stable rotation period and draw a time domain curve graph.

[0096] This embodiment also provides a computer device, which is suitable for the case of a rapid numerical prediction method for flow-induced noise of hydraulic machinery, and includes a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement the rapid numerical prediction method for flow-induced noise of hydraulic machinery as proposed in the above embodiment.

[0097] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0098] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for rapid numerical prediction of flow-induced noise of hydraulic machinery as proposed in the above embodiment is implemented.

[0099] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0100] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for rapid numerical prediction of flow-induced noise in hydraulic machinery, characterized by: The following steps are included: Obtain external characteristic test data of hydraulic machinery; Establish the fluid domain model of hydraulic machinery and divide the structural grid to perform steady-state numerical simulation under different working conditions; Compare the constant numerical simulation results with the experimental results; After the unsteady numerical simulation results converge, draw the time domain curve of the flow-induced noise sound pressure level; The frequency domain data of flow-induced noise sound pressure level are obtained by calculation.

2. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 1, characterized in that: The external characteristic test data include head, efficiency and shaft power.

3. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 2, characterized in that: The steps for steady-state numerical simulation under different working conditions include: Set the boundary conditions of numerical simulation according to the external characteristic test; Turbulence models are used to predict flow around and rotating flows near walls; Through the prediction results, the steady-state values ​​under different working conditions are obtained.

4. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 3, characterized in that: The steps for comparing the steady-state numerical simulation results with the experimental results include: When the error between the constant numerical simulation result and the test result is greater than 5%, the fluid domain model of the hydraulic machinery is re-established and the structural grid is divided; When the error between the steady numerical simulation results and the test results is no more than 5%, the steady numerical simulation results are used as the initial conditions to carry out unsteady numerical simulations under different working conditions, and the sound pressure level of the flow-induced noise of the hydraulic machinery at different times is solved.

5. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 4, characterized in that: The steps to solve the flow-induced noise sound pressure level of hydraulic machinery at different times include: Set X rotation cycles, the time is not as long as 1 / n; Write the calculation formula for solving the sound pressure level using CEL language; The calculation formula is expressed as: Where, L p It is expressed as sound pressure level, expressed as the logarithmic form of the ratio of the actual sound pressure P to the reference sound pressure P0.

6. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 5, characterized in that: The steps of plotting a time domain graph of flow induced noise sound pressure level include: The flow-induced noise sound pressure level in the last Y stable rotation periods is derived in the solver as a support for flow-induced noise data processing, and different cross sections are made to obtain time domain curves; The time domain curve diagram is used to view the sound pressure level cloud diagram of the flow field at different positions and at different times, and to study the characteristics and laws of the sound field.

7. The method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to claim 6, characterized in that: The method for obtaining the frequency domain data of flow-induced noise sound pressure level includes: According to the A weighted calculation formula, the formula is expressed as: In the formula, Laeq represents the equivalent continuous sound pressure level, T represents time, p(t) represents instantaneous sound pressure, and A is the weighted value of the sound pressure level; Write the code of A-weighted correction algorithm to correct the obtained sound pressure level frequency domain data to obtain the corrected flow-induced noise sound pressure level frequency domain data; The frequency domain data obtained by A-weighted correction is subjected to iFFT transformation to obtain the corrected time domain data of the flow induced noise sound pressure level, thereby drawing the corrected time domain curve of the flow induced noise sound pressure level.

8. A rapid numerical prediction system for flow-induced noise of hydraulic machinery, based on the rapid numerical prediction method for flow-induced noise of hydraulic machinery according to any one of claims 1 to 7, characterized in that: It includes data acquisition module, numerical simulation module, result comparison module, and data processing visualization module; The data acquisition module is used to acquire the external characteristic test data of the hydraulic machinery, including head, efficiency, and shaft power; The numerical simulation module is used to establish a fluid domain model of hydraulic machinery and perform steady and unsteady numerical simulations; The result comparison module is used to compare the numerical simulation results with the test results to evaluate the accuracy of the simulation; The data processing and visualization module is used to derive the flow-induced noise sound pressure level data within a stable rotation period and draw a time domain curve graph.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for rapid numerical prediction of flow-induced noise of hydraulic machinery according to any one of claims 1 to 7 are implemented.

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