Noise analysis method and device for inlet and outlet flow of self-flowing cooling system and storage medium

Abstract

The invention discloses a self-flow cooling system inlet and outlet flow noise forecasting method and device and a storage medium, and the method comprises the steps: constructing a one-dimensional model of an inner drainage basin element and a three-dimensional model of an outer drainage basin element of a self-flow cooling system, a node is arranged at the joint of each element in the one-dimensional model to obtain pressure information, the flow source is coupled with a coupling surface at a pipeline inlet, the pressure source is coupled with a coupling surface at a pipeline outlet, the outer watershed element is composed of an underwater vehicle shell, an inlet and an outlet, and in the three-dimensional model, the sea port outlet and the inlet are prolonged by 1 m at the same time. The position where the outlet and the inlet of the seaport are extended by 1 m is used as a coupling surface; setting a flow field boundary condition of one-dimensional-three-dimensional coupling calculation, building a one-dimensional-three-dimensional coupling model of the self-flowing cooling system based on coupling area data exchange, and performing one-dimensional-three-dimensional coupling flow field calculation; and performing sound field calculation based on a fluid pulsation result obtained by flow field calculation. According to the method, the one-dimensional-three-dimensional coupling method is applied to the self-flowing cooling system model, a new method is provided for flow noise forecasting of the self-flowing cooling system, and meanwhile calculation resources and calculation time are saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater navigation bodies, and in particular relates to a method, a device and a storage medium for analyzing inlet and outlet flow noise of a gravity cooling system. Background Art

[0002] Modern underwater vehicles use a gravity cooling circulation system to provide cooling water for the condenser, referred to as a gravity cooling system. During navigation, the flow of fluid inside the gravity cooling system pipe will generate flow noise and radiate outward from the sea outlet, directly affecting the marine ecological environment. The flow noise of the gravity cooling system sea-going pipeline is an important noise source of the underwater vehicle flow noise. Effectively suppressing the radiation noise of the gravity cooling system sea-going pipeline inlet and outlet is an important link in achieving low noise for underwater vehicles.

[0003] As a sea-going pipeline, the gravity cooling system is generally composed of water inlet / outlet, valve / pump components, condenser, grille, and fairing. It is very important to fully understand the generation and propagation process of flow noise in the sea-going pipeline of the gravity cooling system, as well as the radiation characteristics of the inlet and outlet. For simulation research, considering the large scale and complex model of the gravity cooling system, a method is needed to reduce the amount of calculation and the simulation time.

[0004] Moreover, the internal flow noise of the gravity cooling system is transmitted to the inlet and outlet through the fluid and radiated directly outward. It is relatively difficult to reduce this part of the noise, so it has become the focus of current research on noise radiation of gravity cooling systems. Summary of the invention

[0005] In view of the defects in the above-mentioned prior art, the present invention provides a method, device and storage medium for analyzing the inlet and outlet flow noise of a gravity cooling system. The method comprises the following steps:

[0006] Determine the structure of the underwater vehicle gravity cooling system, including the underwater vehicle shell, inlet and outlet eccentric butterfly valves, condenser and pipe connection;

[0007] Construct a one-dimensional model of the inner flow basin element and a three-dimensional model of the outer flow basin element of the gravity cooling system, wherein the inner flow basin element is composed of an eccentric butterfly valve, a condenser and a pipe connection, a node is set at each element connection in the one-dimensional model to obtain pressure information, a coupling surface at the flow source and the pipeline inlet is coupled, and a coupling surface at the pressure source pipeline outlet is coupled, and the outer flow basin element is composed of an underwater vehicle shell, an inlet and an outlet, and in the three-dimensional model, the Tonghaikou outlet and the inlet are extended by 1m at the same time, and the position where the Tonghaikou outlet and the inlet are extended by 1m is used as a coupling surface;

[0008] Set the flow field boundary conditions for the one-dimensional-three-dimensional coupling calculation, build a one-dimensional-three-dimensional coupling model of the self-flow cooling system based on the coupling area data exchange, and perform one-dimensional-three-dimensional coupling flow field calculation;

[0009] Based on the fluid pulsation results obtained by flow field calculation, the acoustic field calculation is performed.

[0010] Among them, the one-dimensional model of the inner flow basin components of the gravity cooling system includes:

[0011] Construct a one-dimensional condenser model: The condenser is abstracted as a tube bundle connecting two water tanks with multiple tube bundles in the middle. Each water tank can be set to have a variable cross-sectional area and can be assigned a different height. The total pressure loss of the one-dimensional condenser model is composed of the sum of the inlet loss, outlet loss and pipeline loss.

[0012] Construct a one-dimensional eccentric butterfly valve model: The one-dimensional eccentric butterfly valve model uses a double eccentric butterfly valve as an element, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure the continuous flow of the fluid. The total pressure loss equation of the eccentric butterfly valve in the one-dimensional model is:

[0013]

[0014] Among them, P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, ρ is the fluid density, A is the inner diameter area, and K is the loss coefficient, which is related to the valve type, pipe diameter, valve opening and Reynolds number. is the mass flow rate at the outlet;

[0015] Construct a one-dimensional pipeline model: The one-dimensional pipeline model uses a straight pipe model with a circular cross-section, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure continuous flow of the fluid. The total pressure loss equation of the pipeline in the one-dimensional model is:

[0016]

[0017] Where P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, f is the friction coefficient, L is the pipe length, ρ is the fluid density, A is the inner diameter area, is the mass flow rate at the pipe inlet.

[0018] Among them, the three-dimensional model of the inner flow basin components of the gravity cooling system includes:

[0019] Construct a three-dimensional model of the inlet of the gravity cooling system: the inlet parameters include the outlet diameter of the inlet pipe Φ, the length of the inlet pipe section L1, the horizontal distance L2 from the tangent line at the end of the arc section of the center line of the inlet pipe to the center of the inlet section, the arc radius R of the center line of the inlet pipe, the inlet height H of the inlet pipe, the inlet aspect ratio B1 / H, the total length LT of the inlet pipe guide cover, the distance δ between the inlet end of the inlet pipe and the wall of the main model, the angle ɑ between the center line arc section and the horizontal line, and the bevel angle β of the guide cover;

[0020] Construct a three-dimensional model of the outlet of the gravity cooling system: the outlet parameters include the outlet pipe inlet diameter Φ, the cross-sectional diameter Φ1, the major axis of the ellipse at the end of the gradually expanding part Φ2, the outlet pipe length L3, the gradually expanding part height B2, the distance C between the beveled part of the fairing and the main model, the outlet pipe fairing chamfer γ, and the angle ε between the underwater part of the outlet pipe side wall and the vertical plane.

[0021] Among them, the one-dimensional-three-dimensional coupling model of the self-flow cooling system based on the coupling area data exchange includes:

[0022] The data exchange includes an association process and an interpolation process. In constructing a one-dimensional-three-dimensional coupling model of a gravity cooling system, data is extracted from the one-dimensional model and applied to the grid of the three-dimensional model. A single integral point and a surface grid are paired at the coupling surface, and flux interpolation and / or field interpolation are determined according to the type of data.

[0023] Based on the coupling algorithm, the coupling mode, iteration method, relaxation factor and convergence criterion are pre-set, wherein the coupling mode is weak bidirectional coupling, and the iterative coupling algorithm adopts the Gauss-Seidel algorithm;

[0024] The relaxation factor is used to adjust the relaxation degree of data exchange. The formula is as follows:

[0025]

[0026] Where α is the relaxation factor, is the current iteration mapping value, which is the value mapped from the sender to the receiver grid. is the value received by the receiver in the previous iteration, is the new relaxation value, which is the updated value sent to the receiver, and is calculated by weighting the current iterative mapping value and the last received value with the relaxation factor;

[0027] The difference is quantified based on the convergence criterion, and the formula is as follows:

[0028]

[0029] Among them, q n is the nth coupling value, q n+1is the n+1th coupling value, ||·|| ∞ is an infinite norm.

[0030] Wherein, the flow field boundary conditions include:

[0031] Turbulence model: The standard k-ε turbulence model is used initially, and after stabilization, it is switched to the LES large eddy model to capture more detailed flow characteristics;

[0032] Numerical method: Segregated solver, turbulent kinetic energy, turbulent dissipation term, and momentum equation are all discretized using the second-order upwind format;

[0033] Solution algorithm: SIMPLEC algorithm is used for pressure-velocity coupling calculation;

[0034] Boundary conditions: The fluid inlet boundary condition is set as the velocity inlet, and the outlet boundary condition is set as the pressure outlet. In the one-dimensional-three-dimensional coupling, the pipe inlet coupling surface is set as the pressure outlet, and the pipe outlet coupling surface is set as the mass flow inlet. The mass flow and total pressure data are exchanged with the one-dimensional flow source and pressure source at the coupling surface.

[0035] Wall treatment: The non-slip standard wall function is applied to the underwater vehicle shell and pipeline wall;

[0036] Symmetric boundary: The outer surface of the computational domain is set as the symmetric surface;

[0037] Fluid medium: water;

[0038] Time step: 0.0004s.

[0039] The shell surface and pipeline of the underwater vehicle are set as rigid walls, the main sound source domain is intercepted in the fluid domain as the volume sound source, the sound propagation domain is the area between the sound source domain and the infinite element boundary, and its internal source term is zero. The acoustic model is constructed based on the sound source domain, the sound propagation domain and the infinite boundary, including two acoustic models: the sound source domain without pipeline and the sound source domain with pipeline;

[0040] Select the maximum analysis frequency f max =1000Hz, underwater sound speed c = 1500m / s, minimum wavelength λ = c / f max =1.5m;

[0041] Set up far-field and near-field acoustic monitoring points. The far-field acoustic monitoring points consist of measuring points on three orthogonal planes, corresponding to the x, y and z axes respectively. With the center coordinates of the model as the center of the circle, 72 measuring points are arranged on each plane, for a total of 216 measuring points. Main measuring points are set up at five key positions of the far-field measuring points, and near-field acoustic monitoring points are set at the inlet and outlet of the pipeline;

[0042] Based on the working condition of 12kn speed, the flow characteristics and acoustic field characteristics of the gravity cooling system are analyzed to obtain the resistance loss coefficient of each component in the gravity cooling system model. Based on the analysis frequency of 20-1000Hz, The sound pressure level SPL at each measuring point ii Convert it into the corresponding sound energy value, add it up and then calculate the average value to get the average sound energy value. 总 =10×log 10 The average total sound pressure level of multiple measuring points is obtained by calculating the average total sound source level of the gravity cooling system in the far field.

[0043] Among them, the standard k-ε model contains two transport equations: the turbulent kinetic energy k equation and the turbulent dissipation rate ε equation. The transport equation of the standard k-ε model is:

[0044]

[0045] in, G k and G b is the turbulent kinetic energy term, G k Caused by the average velocity gradient, G b Caused by buoyancy; Y M is the effect of compressible turbulent pulsation expansion on the total dissipation rate; C 1ε , C 2ε , C 3ε are empirical values, and the default values ​​are C 1ε =1.44, C 2ε =1.92, C 3ε =0.09;σ k , σ ε are the Prandtl numbers corresponding to the k equation and the ε equation, and their default values ​​are σ k =1.0,σ ε =1.3; S k and S ε For custom items; Pr t is the turbulent Planck number, which is taken as Pr by default t =0.85; g i is the gravitational acceleration component; β is the thermal expansion coefficient; M t is the turbulent Mach number; a is the speed of sound.

[0046] Among them, the continuity equation and kinetic equation in the LES model can be expressed as:

[0047]

[0048] Among them, u i Represents x i There are velocity components associated with is the average velocity component after filtration, ρ is the fluid density, It is the sub-grid stress that describes the effect of small-scale eddies on large-scale eddies;

[0049] According to the Boussinesq eddy viscosity hypothesis, It can also be expressed as:

[0050]

[0051] Among them, μ t is the turbulent viscosity; τ kk represents the isotropic part of the sub-grid stress; δ ij is the Dirac function; S ij The tensor representing the Reynolds-scale strain can be expressed as:

[0052]

[0053] The turbulent viscosity is solved using the sub-grid stress model WALE model, and the calculation formula for the turbulent viscosity μt is as follows:

[0054]

[0055] Among them, the turbulent length dimension L s and is defined as follows:

[0056] L s =min(κd,C w V 1 / 3 )

[0057]

[0058] Where, κ is the non-Karman constant; d is the distance to the adjacent wall; C w is the WALE constant, which takes a value of 0.325; V 1 / 3 is the grid length size.

[0059] The present invention establishes an original model of a gravity cooling system, performs three-dimensional modeling of the inlet, outlet and external flow domain, performs one-dimensional modeling of flow domain components in pipelines such as condensers and butterfly valves, and studies the flow field characteristics and acoustic field characteristics of the gravity cooling system model based on a one-dimensional-three-dimensional coupling calculation method. This not only provides a new method for predicting flow noise in a gravity cooling system, but also saves computing resources and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0061] Figure 1 is a flow chart showing a method for analyzing inlet and outlet flow noise of a gravity cooling system according to an embodiment of the present invention;

[0062] Figure 2 It is the flow diagram of the gravity cooling system;

[0063] Figure 3 It is a schematic diagram of the one-dimensional model of the flow domain in the gravity cooling system;

[0064] Figure 4 It is a schematic diagram of the three-dimensional model of the outer basin;

[0065] Figure 5 It is a schematic diagram of the one-dimensional-three-dimensional coupled flow field model of the gravity cooling system and the boundary condition setting;

[0066] Figure 6 It is a schematic diagram of the 1D-3D coupled grid association;

[0067] Figure 7 It is the acoustic radiation cloud diagram of different frequencies of the gravity cooling system. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0070] It should be understood that although the terms first, second, third, etc. may be used to describe ... in the embodiments of the present invention, these ... should not be limited to these terms. These terms are only used to distinguish .... For example, without departing from the scope of the embodiments of the present invention, the first ... may also be referred to as the second ..., and similarly, the second ... may also be referred to as the first ....

[0071] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0072] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0073] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0074] The noise of the gravity cooling system is an important noise source of the flow noise of underwater vehicles. The inner and outer flow basins of the gravity cooling system, as a whole, have gravity characteristics, that is, the flow of the outer flow basin drives the flow of the inner flow basin. The interaction between the inner and outer flow basins forms a driving effect, which directly affects the change of the pressure of the flow in the system.

[0075] It is very important to fully understand the generation and propagation process of flow noise in the sea pipeline of the gravity cooling system and the radiation characteristics of the inlet and outlet. For simulation research, considering the large scale and complex model of the gravity cooling system, a method is needed to reduce the amount of calculation and reduce the simulation time.

[0076] like Figure 1 As shown, the present invention discloses a method for analyzing inlet and outlet flow noise of a gravity cooling system, the method comprising:

[0077] Determine the composition structure of the underwater vehicle gravity cooling system, including the underwater vehicle shell, inlet, outlet, eccentric butterfly valve, condenser and connecting pipe.

[0078] As a sea-going pipeline, the gravity cooling system is generally composed of water inlet / outlet, valve / pump components, condenser, grille and fairing. Its working principle is to use the dynamic head generated by the relative movement of the navigation body and the seawater to increase the water pressure at the pipeline inlet and reduce the water pressure at the pipeline outlet, so as to push the cooling water through the system and flow through the main condenser, thus effectively realizing the circulation of cooling water. Figure 2 shown.

[0079] The flow noise of the gravity cooling system mainly comes from the noise generated by the unstable flow of the fluid through components such as pumps and valves, as well as the noise generated by the fluid entering and discharging the gravity cooling system pipeline.

[0080] A one-dimensional model of the inner flow basin element and a three-dimensional model of the outer flow basin element of the gravity cooling system are constructed, wherein the inner flow basin element is composed of an eccentric butterfly valve, a condenser and a pipe connection. A node is set at the connection of each element in the one-dimensional model to obtain pressure information, the flow source is coupled with the coupling surface at the pipeline inlet, and the coupling surface at the pressure source pipeline outlet is coupled. The outer flow basin element is composed of an underwater vehicle shell, an inlet and an outlet. In the three-dimensional model, the Tonghaikou outlet and the inlet are extended by 1m at the same time, and the position where the Tonghaikou outlet and the inlet are extended by 1m is used as the coupling surface.

[0081] The original model of the gravity cooling system includes an inlet (including a guide cover), an outlet, an eccentric butterfly valve, a condenser, an axial flow pump and a connecting pipe. Figure 3 As shown, eccentric butterfly valves 1 and 2 are connected in series, and eccentric butterfly valves 3 and 4 are connected in series.

[0082] In one embodiment, constructing a one-dimensional model of an inner flow basin element of a gravity cooling system includes:

[0083] Construct a one-dimensional condenser model: The condenser is abstracted as a tube bundle connecting two water tanks with multiple tube bundles in the middle. Each water tank can be set to have a variable cross-sectional area and can be assigned a different height. The total pressure loss of the one-dimensional condenser model is composed of the sum of the inlet loss, outlet loss and pipeline loss.

[0084] Construct a one-dimensional eccentric butterfly valve model: The one-dimensional eccentric butterfly valve model uses a double eccentric butterfly valve as an element, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure the continuous flow of the fluid. The total pressure loss equation of the eccentric butterfly valve in the one-dimensional model is:

[0085]

[0086] Among them, P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, ρ is the fluid density, A is the inner diameter area, and K is the loss coefficient, which is related to the valve type, pipe diameter, valve opening and Reynolds number. is the mass flow rate at the outlet;

[0087] Construct a one-dimensional pipeline model: The one-dimensional pipeline model uses a straight pipe model with a circular cross-section, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure continuous flow of the fluid. The total pressure loss equation of the pipeline in the one-dimensional model is:

[0088]

[0089] Where P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, f is the friction coefficient, L is the pipe length, ρ is the fluid density, A is the inner diameter area, is the mass flow rate at the pipe inlet.

[0090] The outer flow domain includes the pipeline inlet (flow guide) and the pipeline outlet. The outer flow domain is 3D modeled. In order to ensure the uniformity and stability of the flow at the coupling surface, the position where the outlet and the inlet are extended by 1m is taken as the coupling surface, such as Figure 4 shown.

[0091] In one embodiment, constructing a three-dimensional model of an inner flow basin element of a gravity cooling system includes:

[0092] Construct a three-dimensional model of the inlet of the gravity cooling system: the inlet parameters include the outlet diameter of the inlet pipe Φ, the length of the inlet pipe section L1, the horizontal distance L2 from the tangent line at the end of the arc section of the center line of the inlet pipe to the center of the inlet section, the arc radius R of the center line of the inlet pipe, the inlet height H of the inlet pipe, the inlet aspect ratio B1 / H, the total length LT of the inlet pipe guide cover, the distance δ between the inlet end of the inlet pipe and the wall of the main model, the angle ɑ between the center line arc section and the horizontal line, and the bevel angle β of the guide cover;

[0093] Construct a three-dimensional model of the outlet of the gravity cooling system: the outlet parameters include the outlet pipe inlet diameter Φ, the cross-sectional diameter Φ1, the major axis of the ellipse at the end of the gradually expanding part Φ2, the outlet pipe length L3, the gradually expanding part height B2, the distance C between the beveled part of the fairing and the main model, the outlet pipe fairing chamfer γ, and the angle ε between the underwater part of the outlet pipe side wall and the vertical plane.

[0094] The flow field boundary conditions for the one-dimensional-three-dimensional coupling calculation are set, a one-dimensional-three-dimensional coupling model of the gravity cooling system is constructed based on the coupling area data exchange, and the one-dimensional-three-dimensional coupling flow field calculation is performed.

[0095] Before simulating the gravity cooling system, it is necessary to set the boundary conditions and initialize the parameters. Figure 5 The flow field boundary conditions for 1D-3D coupled calculations are demonstrated.

[0096] In one embodiment, the flow field boundary conditions include:

[0097] Turbulence model: The standard k-ε turbulence model is used initially, and after stabilization, it is switched to the LES large eddy model to capture more detailed flow characteristics;

[0098] Numerical method: Segregated solver, turbulent kinetic energy, turbulent dissipation term, and momentum equation are all discretized using the second-order upwind format;

[0099] Solution algorithm: SIMPLEC algorithm is used for pressure-velocity coupling calculation;

[0100] Boundary conditions: The fluid inlet boundary condition is set as the velocity inlet, and the outlet boundary condition is set as the pressure outlet. In the one-dimensional-three-dimensional coupling, the pipe inlet coupling surface is set as the pressure outlet, and the pipe outlet coupling surface is set as the mass flow inlet. The mass flow and total pressure data are exchanged with the one-dimensional flow source and pressure source at the coupling surface.

[0101] Wall treatment: The non-slip standard wall function is applied to the underwater vehicle shell and pipeline wall;

[0102] Symmetric boundary: The outer surface of the computational domain is set as the symmetric surface;

[0103] Fluid medium: water;

[0104] Time step: 0.0004s.

[0105] In one embodiment, the standard k-ε model includes two transport equations: the turbulent kinetic energy k equation and the turbulent dissipation rate ε equation. The transport equation of the standard k-ε model is:

[0106]

[0107] in, G k and G b is the turbulent kinetic energy term, G k Caused by the average velocity gradient, G b Caused by buoyancy; Y M is the effect of compressible turbulent pulsation expansion on the total dissipation rate; C 1ε , C 2ε , C 3ε are empirical values, and the default values ​​are C 1ε =1.44, C 2ε =1.92, C 3ε =0.09;σ k , σ ε are the Prandtl numbers corresponding to the k equation and the ε equation, and their default values ​​are σ k =1.0,σ ε =1.3; S kand S ε For custom items; Pr t is the turbulent Planck number, which is taken as Pr by default t =0.85; g i is the gravitational acceleration component; β is the thermal expansion coefficient; M t is the turbulent Mach number; a is the speed of sound.

[0108] In one embodiment, the continuity equation and the kinetic equation in the LES model can be expressed as:

[0109]

[0110] Among them, u i Represents x i There are velocity components associated with is the average velocity component after filtration, ρ is the fluid density, It is the sub-grid stress that describes the effect of small-scale eddies on large-scale eddies;

[0111] According to the Boussinesq eddy viscosity hypothesis, It can also be expressed as:

[0112]

[0113] Among them, μ t is the turbulent viscosity; τ kk represents the isotropic part of the sub-grid stress; δ ij is the Dirac function; S ij The tensor representing the Reynolds-scale strain can be expressed as:

[0114]

[0115] The turbulent viscosity is solved using the sub-grid stress model WALE model, and the calculation formula for the turbulent viscosity μt is as follows:

[0116]

[0117] Among them, the turbulent length dimension L s and is defined as follows:

[0118] L s =min(κd,C w V 1 / 3 )

[0119]

[0120] Where, κ is the non-Karman constant; d is the distance to the adjacent wall; C w is the WALE constant, which takes a value of 0.325; V1 / 3 is the grid length size.

[0121] 1D-3D coupling is achieved through data exchange in the coupling area. This process can be divided into two issues: how to transfer data and when to transfer data. The data exchange mechanism of 1D-3D coupling is the key technology to achieve coupling between models of different dimensions. This process requires extracting data from the simplified representation of the 1D model and accurately applying it to the detailed mesh of the 3D model, and vice versa.

[0122] The data exchange process can be divided into two steps: association and interpolation. (1) Association. For each node or element of a grid, the goal of association is to determine the exact correspondence between each node or element in the sending grid and the corresponding position on the receiving grid. Data can then be exchanged between these associated nodes and / or elements. In 1D-3D coupling, a single integration point is paired with the surface grid at the coupling surface. Figure 6 As shown. (2) Interpolation. According to the type of data, the interpolation process is divided into flux interpolation (such as mass flow) and field interpolation (such as pressure field). The transmitted data must be adapted to the target grid. Flux interpolation adjusts the integral based on the cell size to ensure the physical consistency and accuracy of the data. Field interpolation involves interpolating the field data using shape functions to ensure accurate transmission of the data in spatial distribution.

[0123] In one embodiment, constructing a one-dimensional-three-dimensional coupling model of a gravity cooling system based on coupling region data exchange includes:

[0124] The data exchange includes an association process and an interpolation process. In constructing a one-dimensional-three-dimensional coupling model of a gravity cooling system, data is extracted from the one-dimensional model and applied to the grid of the three-dimensional model. A single integral point and a surface grid are paired at the coupling surface, and flux interpolation and / or field interpolation are determined according to the type of data.

[0125] Based on the coupling algorithm, the coupling mode, iteration method, relaxation factor and convergence criterion are pre-set, wherein the coupling mode includes weak bidirectional coupling, and the iterative coupling algorithm adopts the Gauss-Seidel algorithm;

[0126] The relaxation factor is used to adjust the relaxation degree of data exchange. The formula is as follows:

[0127]

[0128] Where α is the relaxation factor, is the current iteration mapping value, which is the value mapped from the sender to the receiver grid. is the value received by the receiver in the previous iteration, is the new relaxation value, which is the updated value sent to the receiver, and is calculated by weighting the current iterative mapping value and the last received value with the relaxation factor;

[0129] The difference is quantified based on the convergence criterion, and the formula is as follows:

[0130]

[0131] Among them, q n is the nth coupling value, q n+1 is the n+1th coupling value, ||·|| ∞ is an infinite norm.

[0132] Based on the fluid pulsation results obtained by flow field calculation, the acoustic field calculation is performed.

[0133] In one embodiment, the surface of the underwater vehicle shell and the pipeline are set as rigid walls, the main sound source domain is intercepted in the fluid domain as the volume sound source, the sound propagation domain is the area between the sound source domain and the infinite element boundary, and its internal source term is zero, and the acoustic model is constructed based on the sound source domain, the sound propagation domain and the infinite boundary;

[0134] Select the maximum analysis frequency f max =1000Hz, underwater sound speed c = 1500m / s, minimum wavelength λ = c / f max =1.5m;

[0135] Set up far-field and near-field acoustic monitoring points. The far-field acoustic monitoring points consist of measuring points on three orthogonal planes, corresponding to the x, y and z axes respectively. With the center coordinates of the model as the center of the circle, 72 measuring points are arranged on each plane, for a total of 216 measuring points. Main measuring points are set up at five key positions of the far-field measuring points, and near-field acoustic monitoring points are set at the inlet and outlet of the pipeline;

[0136] Based on the working condition of 12kn speed, the flow characteristics and acoustic field characteristics of the gravity cooling system are analyzed to obtain the resistance loss coefficient of each component in the gravity cooling system model. Based on the analysis frequency of 20-1000Hz, The sound pressure level SPL at each measuring point ii Convert it into the corresponding sound energy value, add it up and then calculate the average value to get the average sound energy value. 总 =10×log 10 The average total sound pressure level of multiple measuring points is obtained by calculating the average total sound source level of the gravity cooling system in the far field.

[0137] The acoustic radiation cloud diagram of the self-flow cooling system with different frequencies is shown in Figure 7 shown.

[0138] The present invention establishes an original model of a gravity cooling system, performs three-dimensional modeling of the inlet, outlet and external flow domain, performs one-dimensional modeling of flow domain components in pipelines such as condensers and butterfly valves, and studies the flow field characteristics and acoustic field characteristics of the gravity cooling system model based on a one-dimensional-three-dimensional coupling calculation method. This not only provides a new method for predicting flow noise in a gravity cooling system, but also saves computing resources and time.

[0139] It should be noted that the computer-readable medium disclosed above may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0140] The computer-readable medium may be included in the electronic device, or may exist independently without being installed in the electronic device.

[0141] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0142] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0143] The units involved in the embodiments described in the present disclosure may be implemented by software or hardware, wherein the name of a unit does not, in some cases, limit the unit itself.

[0144] The above introduces the preferred embodiments of the present invention, which is intended to make the spirit of the present invention clearer and easier to understand, but is not intended to limit the present invention. All modifications, substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection outlined by the claims attached to the present invention.

Claims

1. A method for analyzing inlet and outlet flow noise of a gravity cooling system, comprising: Determine the structure of the underwater vehicle gravity cooling system, including the underwater vehicle shell, inlet, outlet, eccentric butterfly valve, condenser and pipe; Construct a one-dimensional model of the inner flow basin element and a three-dimensional model of the outer flow basin element of the gravity cooling system, wherein the inner flow basin element is composed of an eccentric butterfly valve, a condenser and a pipe connection, a node is set at each element connection in the one-dimensional model to obtain pressure information, a coupling surface at the flow source and the pipeline inlet is coupled, and a coupling surface at the pressure source pipeline outlet is coupled, and the outer flow basin element is composed of an underwater vehicle shell, an inlet and an outlet, and in the three-dimensional model, the Tonghaikou outlet and the inlet are extended by 1m at the same time, and the position where the Tonghaikou outlet and the inlet are extended by 1m is used as a coupling surface; Set the flow field boundary conditions for the one-dimensional-three-dimensional coupling calculation, build a one-dimensional-three-dimensional coupling model of the self-flow cooling system based on the coupling area data exchange, and perform one-dimensional-three-dimensional coupling flow field calculation; Based on the fluid pulsation results obtained by flow field calculation, the acoustic field calculation is performed.

2. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 1, characterized in that: The one-dimensional model of the inner flow components of the gravity cooling system includes: Construct a one-dimensional condenser model: The condenser is abstracted as a tube bundle connecting two water tanks with multiple tube bundles in the middle. Each water tank can be set to have a variable cross-sectional area and can be assigned a different height. The total pressure loss of the one-dimensional condenser model is composed of the sum of the inlet loss, outlet loss and pipeline loss. Construct a one-dimensional eccentric butterfly valve model: The one-dimensional eccentric butterfly valve model uses a double eccentric butterfly valve as an element, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure the continuous flow of the fluid. The total pressure loss equation of the eccentric butterfly valve in the one-dimensional model is: Among them, P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, ρ is the fluid density, A is the inner diameter area, and K is the loss coefficient, which is related to the valve type, pipe diameter, valve opening and Reynolds number. is the mass flow rate at the outlet; Construct a one-dimensional pipeline model: The one-dimensional pipeline model uses a straight pipe model with a circular cross-section, in which the inlet is connected to a flow source and the outlet is connected to a pressure source to ensure continuous flow of the fluid. The total pressure loss equation of the pipeline in the one-dimensional model is: Where P1 is the pressure at the pipe inlet, P2 is the pressure at the pipe outlet, f is the friction coefficient, L is the pipe length, ρ is the fluid density, A is the inner diameter area, is the mass flow rate at the pipe inlet.

3. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 1, characterized in that: The three-dimensional model of the inner flow basin components of the gravity cooling system includes: Construct a three-dimensional model of the inlet of the gravity cooling system: the inlet parameters include the outlet diameter of the inlet pipe Φ, the length of the inlet pipe section L1, the horizontal distance L2 from the tangent line at the end of the arc section of the center line of the inlet pipe to the center of the inlet section, the arc radius R of the center line of the inlet pipe, the inlet height H of the inlet pipe, the inlet aspect ratio B1 / H, the total length LT of the inlet pipe guide cover, the distance δ between the inlet end of the inlet pipe and the wall of the main model, the angle ɑ between the center line arc section and the horizontal line, and the bevel angle β of the guide cover; Construct a three-dimensional model of the outlet of the gravity cooling system: the outlet parameters include the outlet pipe inlet diameter Φ, the cross-sectional diameter Φ1, the major axis of the ellipse at the end of the gradually expanding part Φ2, the outlet pipe length L3, the gradually expanding part height B2, the distance C between the beveled part of the fairing and the main model, the outlet pipe fairing chamfer γ, and the angle ε between the underwater part of the outlet pipe side wall and the vertical plane.

4. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 1, characterized in that: The one-dimensional-three-dimensional coupling model of the gravity cooling system based on the coupled area data exchange includes: The data exchange includes an association process and an interpolation process. In constructing a one-dimensional-three-dimensional coupling model of a gravity cooling system, data is extracted from the one-dimensional model and applied to the grid of the three-dimensional model. A single integral point and a surface grid are paired at the coupling surface, and flux interpolation and / or field interpolation are determined according to the type of data. Based on the coupling algorithm, the coupling mode, iteration method, relaxation factor and convergence criterion are pre-set, wherein the coupling mode is weak bidirectional coupling, and the iterative coupling algorithm adopts the Gauss-Seidel algorithm; The relaxation factor is used to adjust the relaxation degree of data exchange. The formula is as follows: Where α is the relaxation factor, is the current iteration mapping value, which is the value mapped from the sender to the receiver grid. is the value received by the receiver in the previous iteration, is the new relaxation value, which is the updated value sent to the receiver, and is calculated by weighting the current iterative mapping value and the last received value with the relaxation factor; The difference is quantified based on the convergence criterion, and the formula is as follows: Among them, q n is the nth coupling value, q n+1 is the n+1th coupling value, ||·|| ∞ is an infinite norm.

5. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 1, characterized in that: The flow field boundary conditions include: Turbulence model: The standard k-ε turbulence model is used initially, and after stabilization, it is switched to the LES large eddy model to capture more detailed flow characteristics; Numerical method: Separated solver, turbulent kinetic energy, turbulent dissipation term, and momentum equation are all discretized using the second-order upwind format; Solution algorithm: SIMPLEC algorithm is used for pressure-velocity coupling calculation; Boundary conditions: The fluid inlet boundary condition is set as the velocity inlet, and the outlet boundary condition is set as the pressure outlet. In the one-dimensional-three-dimensional coupling, the pipe inlet coupling surface is set as the pressure outlet, and the pipe outlet coupling surface is set as the mass flow inlet. The mass flow and total pressure data are exchanged with the one-dimensional flow source and pressure source at the coupling surface. Wall treatment: The non-slip standard wall function is applied to the underwater vehicle shell and pipeline wall; Symmetric boundary: The outer surface of the computational domain is set as the symmetric surface; Fluid medium: water; Time step: 0.0004s.

6. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 1, characterized in that: The shell surface and pipeline of the underwater vehicle are set as rigid walls, the main sound source domain is intercepted in the fluid domain as the volume sound source, the sound propagation domain is the area between the sound source domain and the infinite element boundary, and its internal source term is zero. The acoustic model is constructed based on the sound source domain, the sound propagation domain and the infinite boundary; Select the maximum analysis frequency f max =1000Hz, underwater sound speed c = 1500m / s, minimum wavelength λ = c / f max =1.5m; Set up far-field and near-field acoustic monitoring points. The far-field acoustic monitoring points consist of measuring points on three orthogonal planes, corresponding to the x, y and z axes respectively. With the center coordinates of the model as the center of the circle, 72 measuring points are arranged on each plane, for a total of 216 measuring points. Main measuring points are set up at five key positions of the far-field measuring points, and near-field acoustic monitoring points are set at the inlet and outlet of the pipeline; Based on the working condition of 12kn speed, the flow characteristics and acoustic field characteristics of the gravity cooling system are analyzed to obtain the resistance loss coefficient of each component in the gravity cooling system model. The sound pressure level SPLi of each measuring point is converted into the corresponding sound energy value, and the average sound energy value is obtained by accumulating and averaging. 总 =10×log 10 The average total sound pressure level of multiple measuring points is obtained by calculating the average total sound source level of the gravity cooling system in the far field.

7. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 5, characterized in that: The standard k-ε model contains two transport equations: the turbulent kinetic energy k equation and the turbulent dissipation rate ε equation. The transport equation of the standard k-ε model is: in, G k and G b is the turbulent kinetic energy term, G k Caused by the average velocity gradient, G b Caused by buoyancy; Y M is the effect of compressible turbulent pulsation expansion on the total dissipation rate; C 1ε , C 2ε , C 3ε are empirical values, and the default values ​​are C 1ε =1.44, C 2ε =1.92, C 3ε =0.09;σ k , σ ε are the Prandtl numbers corresponding to the k equation and the ε equation, and their default values ​​are σ k =1.0,σ ε =1.3; S k and S ε For custom items; Pr t is the turbulent Planck number, which is taken as Pr by default t =0.85; g i is the gravitational acceleration component; β is the thermal expansion coefficient; M t is the turbulent Mach number; a is the speed of sound.

8. A method for analyzing inlet and outlet flow noise of a gravity cooling system according to claim 5, characterized in that: The continuity equation and kinetic equation in the LES model can be expressed as: Among them, u i Represents x i There are velocity components associated with is the average velocity component after filtration, ρ is the fluid density, It is the sub-grid stress that describes the effect of small-scale eddies on large-scale eddies; According to the Boussinesq eddy viscosity hypothesis, τ ij It can also be expressed as: Among them, μ t is the turbulent viscosity; τ kk represents the isotropic part of the sub-grid stress; δ ij is the Dirac function; S ij The tensor representing the Reynolds-scale strain can be expressed as: The turbulent viscosity is solved using the sub-grid stress model WALE model, and its turbulent viscosity μ t The calculation formula is as follows: Among them, the turbulent length dimension L s and is defined as follows: L s =min(κd,C w V 1 / 3 ) Where, κ is the non-Karman constant; d is the distance to the adjacent wall; C w is the WALE constant, which takes a value of 0.325; V 1 / 3 is the grid length size.

9. A device for analyzing inlet and outlet flow noise of a gravity cooling system, comprising: at least one processor; as well as at least one memory including computer program code, The at least one memory and the computer program code are configured to, together with the at least one processor, enable the apparatus to perform the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores one or more programs, and the one or more programs are executed by a processor to implement the method according to any one of claims 1 to 8.

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