Method and device for constructing a multiphase flow water thermal model for pipeline commissioning

Abstract

The embodiment of the present application provides a method and device for constructing a hydrothermal model of multiphase flow in pipeline commissioning. The method includes: determining the non-steady-state multiphase flow model of the pipeline in commissioning through the BN multiphase flow model; determining the pipeline cross-sectional area and pipeline elasticity of the pipeline according to the pressure on the pipeline; determining the pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline; determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow rate of the multiphase flow; determining the multiple flow types included in the multiphase flow of the pipeline, and determining the phase friction of the multiphase flow; determining the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline; constructing a hydrothermal model according to the non-steady-state multiphase flow model, pipeline elasticity, wall friction, phase friction and heat transfer coefficient, so that the constructed hydrothermal model is more accurate, the deviation caused by factors such as friction is reduced, and the hydrothermal risk of pipeline commissioning can be better analyzed, which has higher practicality.

Description

Technical Field

[0001] The present application relates to the technical field of pipeline commissioning, and in particular to a method, a construction device, a storage medium and a processor for constructing a multiphase flow water thermal model for pipeline commissioning. Background Art

[0002] In recent years, as the pace of oil and gas resource development in high-cold areas has gradually accelerated, pipeline construction in permafrost areas has received widespread attention. Oil and gas pipeline projects in permafrost areas are different from those in normal temperature areas in many aspects, such as extremely low temperature transportation environment, higher environmental protection requirements, and special hydrogeological and engineering geological conditions. In addition, due to special terrain, such as plateaus and mountains, the altitude along the pipeline fluctuates greatly, and the oil pipeline faces problems such as dissatisfaction, liquid column separation, and gasification pull-out caused by the large drop. These potential risks are coupled together, posing a huge threat to the commissioning of the pipeline.

[0003] Most of the existing pipeline commissioning designs are based on the engineering experience of pipelines that have been put into production to determine the new pipeline commissioning plan. They are unable to scientifically evaluate the hydrothermal risks of pipeline commissioning, and do not consider factors such as the surrounding environment of the pipeline, phase change, and hydraulics. The final commissioning plan has large deviations and low practicality. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method, a construction device, a storage medium and a processor for constructing a multiphase flow water thermal model for pipeline commissioning.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a method for constructing a multiphase flow water thermal model for pipeline commissioning, the construction method comprising:

[0006] Determine the unsteady multiphase flow model of the pipeline during production through the BN multiphase flow model;

[0007] Obtain the pressure on the pipeline and determine the cross-sectional area of ​​the pipeline according to the pressure;

[0008] Determine the pipe elasticity of the pipe based on the cross-sectional area of ​​the pipe;

[0009] Determine the pressure wave velocity in the pipeline based on the pressure and the fluid density of the multiphase flow in the pipeline;

[0010] Determine the wall friction between the pipe and the multiphase flow according to the pressure wave velocity and the fluid velocity of the multiphase flow;

[0011] Determine multiple flow patterns included in the multiphase flow in the pipeline, and determine the interphase friction of the multiphase flow according to the multiple flow patterns;

[0012] Determine the heat transfer coefficient of the pipeline based on the pipeline parameters of the pipeline;

[0013] The hydrothermal model is constructed based on the unsteady multiphase flow model, pipe elasticity, wall friction, interphase friction and heat transfer coefficient.

[0014] In an embodiment of the present application, the construction method also includes: after constructing a hydrothermal model based on a non-steady-state multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient, obtaining the soil temperature and thermal conductivity of the soil in which the pipeline is located; determining the heat conduction equation of the soil in two-dimensional space based on the soil temperature and thermal conductivity; obtaining the fluid parameters of the multiphase flow, and determining the temperature drop equation of the multiphase flow in one-dimensional space based on the fluid parameters and the pipeline parameters; and constructing a pipe-soil coupled temperature drop model of the pipeline based on the heat conduction equation and the temperature drop equation.

[0015] In the embodiment of the present application, the heat conduction equation is shown in expression (1):

[0016]

[0017] Where T is soil temperature, λ is thermal conductivity, t is time, and x and y are spatial coordinates;

[0018] The temperature drop equation is shown in expression (2):

[0019]

[0020] Among them, α k represents the volume fraction of multiphase flow included in the fluid parameters, ρ k represents the density of multiphase flow including fluid parameters, E k represents the energy of the multiphase flow included in the fluid parameters, A represents the pipe cross-sectional area of ​​the pipe included in the pipe parameters, d represents the diameter of the pipe included in the pipe parameters, T0 represents the initial temperature of the multiphase flow, and π represents the circumference of a circle.

[0021] In an embodiment of the present application, determining the cross-sectional area of ​​the pipeline according to the pressure includes: determining the strain of the pipeline according to the pressure; determining the annular stress of the pipeline according to the strain, and differentiating the annular stress; and determining the cross-sectional area of ​​the pipeline according to the annular stress after the differentiation process.

[0022] In the embodiment of the present application, determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow velocity of the multiphase flow includes calculating the wall friction according to formula (3):

[0023]

[0024] Among them, τ wu represents the wall friction, ρ represents the density of the multiphase flow, d represents the inner diameter of the pipeline, k t represents the dynamic viscosity of the multiphase flow, k xrepresents the thermal conductivity of multiphase flow, u is the fluid flow rate, a is the pressure wave velocity, t represents time, and x represents the spatial coordinate.

[0025] In the embodiment of the present application, determining the interphase friction of the multiphase flow according to multiple flow patterns includes calculating the interphase friction according to formula (4):

[0026]

[0027] Among them, τ i represents the interphase friction, f i represents the friction coefficient of the i-th phase, α i represents the interphase surface integral ratio, ρ i represents the density of phase i fluid, v i is the relative speed.

[0028] In the embodiment of the present application, the pipeline includes an inner wall, an insulation layer, and an outer wall. The pipeline parameters include at least a first heat release coefficient from the pipe flow in the pipeline to the inner wall, a heat transfer coefficient of the insulation layer, a second heat release coefficient from the outer wall of the pipeline to the soil, an inner diameter of the pipeline, an inner diameter of the insulation layer, an outer diameter of the insulation layer, and an outermost diameter of the pipeline. Determining the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline includes calculating the heat transfer coefficient according to formula (5):

[0029]

[0030] Where K represents the heat transfer coefficient, α1 represents the first heat release coefficient, D1 represents the inner diameter of the pipe, and λ i Denotes the thermal conductivity, D u Indicates the inner diameter of the insulation layer, D (i+1) represents the outer diameter of the insulation layer, α2 represents the second heat release coefficient, D w represents the outermost diameter, and D represents the average of the inner diameter of the insulation layer and the outer diameter of the insulation layer.

[0031] A second aspect of the present application provides a processor configured to execute the above-mentioned method for constructing a multiphase flow water thermal model for pipeline commissioning.

[0032] A third aspect of the present application provides a device for constructing a multiphase flow water thermal model for pipeline commissioning, comprising the above-mentioned processor.

[0033] A fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon, which, when executed by a processor, configures the processor to execute the above-mentioned method for constructing a multiphase flow water thermal model for pipeline commissioning.

[0034] Through the above technical solution, a more complete hydrothermal model for pipeline commissioning can be constructed, and the hydrothermal model comprehensively considers the non-steady-state multiphase flow, pipeline elasticity, friction and heat transfer capacity of the pipeline, making the constructed hydrothermal model more accurate and reducing the deviation caused by factors such as friction. It can better analyze the hydrothermal risks of pipeline commissioning and has higher practicality.

[0035] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0037] Figure 1 A schematic diagram of a process flow of a method for constructing a multiphase flow water thermal model for pipeline commissioning according to an embodiment of the present application is schematically shown;

[0038] Figure 2 A schematic diagram schematically shows a flow pattern of a multiphase flow according to an embodiment of the present application;

[0039] Figure 3 A schematic diagram of a pipeline cross section according to an embodiment of the present application is schematically shown;

[0040] Figure 4 The internal structure diagram of a computer device according to an embodiment of the present application is schematically shown. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] Figure 1 The following is a schematic diagram of a method for constructing a multiphase flow water thermal model for pipeline commissioning according to an embodiment of the present application. Figure 1 As shown, in one embodiment of the present application, a method for constructing a multiphase flow water thermal model for pipeline commissioning is provided, comprising the following steps:

[0043] Step 101, determining the unsteady multiphase flow model of the pipeline during production by using the BN multiphase flow model.

[0044] Step 102, obtaining the pressure on the pipeline and determining the cross-sectional area of ​​the pipeline according to the pressure.

[0045] Step 103, determining the pipeline elasticity of the pipeline according to the pipeline cross-sectional area.

[0046] Step 104 : determining the pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline.

[0047] Step 105 : determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid velocity of the multiphase flow.

[0048] Step 106: determine a plurality of flow patterns included in the multiphase flow in the pipeline, and determine the interphase friction of the multiphase flow according to the plurality of flow patterns.

[0049] Step 107, determining the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline.

[0050] Step 108, constructing a hydrothermal model based on the unsteady multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient.

[0051] Multiphase flow generally refers to various forms of two-phase flow, including gas-liquid two-phase flow, gas-solid two-phase flow and liquid-solid two-phase flow. The BN multiphase flow model is a multiphase flow model and is a commonly used two-phase flow model used to describe the dynamic behavior of liquid-gas two-phase fluids. In practical applications, other terms or corrections can be introduced according to research problems and actual conditions to more accurately describe the dynamic behavior of the fluid. The processor can determine the unsteady multiphase flow model of the pipeline in production through the BN multiphase flow model. The processor can also obtain the pressure on the pipeline and determine the pipeline cross-sectional area of ​​the pipeline according to the pressure. After determining the pipeline cross-sectional area of ​​the pipeline, the processor can determine the pipeline elasticity of the pipeline according to the pipeline cross-sectional area. The processor can determine the pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline. After determining the pressure wave velocity, the processor can determine the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow rate of the multiphase flow. In an embodiment of the present application, determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow rate of the multiphase flow includes calculating the wall friction according to formula (3):

[0052]

[0053] Among them, τ wu represents the wall friction, ρ represents the density of the multiphase flow, d represents the inner diameter of the pipeline, k t represents the dynamic viscosity of the multiphase flow, k x represents the thermal conductivity of multiphase flow, u is the fluid flow rate, a is the pressure wave velocity, t represents time, and x represents the spatial coordinate.

[0054] The processor may also determine a plurality of flow patterns included in the multiphase flow of the pipeline, and determine the interphase friction of the multiphase flow according to the plurality of flow patterns. Determining the interphase friction of the multiphase flow according to the plurality of flow patterns includes calculating the interphase friction according to formula (4):

[0055]

[0056] Among them, τ i represents the interphase friction, f i represents the friction coefficient of the i-th phase, α i represents the interphase surface integral ratio, ρ i represents the density of phase i fluid, v i is the relative speed.

[0057] The processor may also determine the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline. In the embodiment of the present application, the pipeline includes an inner wall, an insulation layer, and an outer wall of the pipeline. The pipeline parameters include at least a first heat release coefficient from the pipe flow in the pipeline to the inner wall of the pipe, a thermal conductivity coefficient of the insulation layer, a second heat release coefficient from the outer wall of the pipe to the soil, an inner diameter of the pipeline, an inner diameter of the insulation layer, an outer diameter of the insulation layer, and an outermost diameter of the pipeline. Determining the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline includes calculating the heat transfer coefficient according to formula (5):

[0058]

[0059] Where K represents the heat transfer coefficient, α1 represents the first heat release coefficient, D1 represents the inner diameter of the pipe, and λ i Denotes the thermal conductivity, D i Indicates the inner diameter of the insulation layer, D (i+1) represents the outer diameter of the insulation layer, α2 represents the second heat release coefficient, D w represents the outermost diameter, and D represents the average of the inner diameter of the insulation layer and the outer diameter of the insulation layer.

[0060] The processor can construct a hydrothermal model based on the unsteady-state model, pipe elasticity, wall friction, interphase friction, and heat transfer coefficient.

[0061] Through the above technical solution, a more complete hydrothermal model for pipeline commissioning can be constructed, and the hydrothermal model comprehensively considers the non-steady-state multiphase flow, pipeline elasticity, friction and heat transfer capacity of the pipeline, making the constructed hydrothermal model more accurate and reducing the deviation caused by factors such as friction. It can better analyze the hydrothermal risks of pipeline commissioning and has higher practicality.

[0062] In an embodiment of the present application, the construction method also includes: after constructing a hydrothermal model based on a non-steady-state multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient, obtaining the soil temperature and thermal conductivity of the soil in which the pipeline is located; determining the heat conduction equation of the soil in two-dimensional space based on the soil temperature and thermal conductivity; obtaining the fluid parameters of the multiphase flow, and determining the temperature drop equation of the multiphase flow in one-dimensional space based on the fluid parameters and the pipeline parameters; and constructing a pipe-soil coupled temperature drop model of the pipeline based on the heat conduction equation and the temperature drop equation.

[0063] After constructing a hydrothermal model based on the unsteady multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient, the processor can obtain the soil temperature and thermal conductivity of the soil where the pipeline is located. After obtaining the soil temperature and thermal conductivity, the processor can determine the heat conduction equation of the soil in two-dimensional space based on the soil temperature and thermal conductivity. In the embodiment of the present application, the heat conduction equation is shown in expression (1):

[0064]

[0065] Where T is the soil temperature, λ is the thermal conductivity, t is the time, and x and y are the spatial coordinates.

[0066] The processor can also obtain the fluid parameters of the multiphase flow, and determine the temperature drop equation of the multiphase flow in one-dimensional space according to the fluid parameters and the pipeline parameters. In the embodiment of the present application, the temperature drop equation is shown in expression (2):

[0067]

[0068] Among them, α k represents the volume fraction of multiphase flow included in the fluid parameters, ρ k represents the density of multiphase flow including fluid parameters, E k represents the energy of the multiphase flow included in the fluid parameters, A represents the pipe cross-sectional area of ​​the pipe included in the pipe parameters, d represents the diameter of the pipe included in the pipe parameters, T0 represents the initial temperature of the multiphase flow, and π represents the circumference of a circle.

[0069] After determining the heat conduction equation and the temperature drop equation, the processor can construct a pipe-soil coupled temperature drop model of the pipeline according to the heat conduction equation and the temperature drop equation to realize the hydrothermal analysis of the pipeline in the frozen soil low temperature and large drop environment.

[0070] In an embodiment of the present application, determining the cross-sectional area of ​​the pipeline according to the pressure includes: determining the strain of the pipeline according to the pressure; determining the annular stress of the pipeline according to the strain, and differentiating the annular stress; and determining the cross-sectional area of ​​the pipeline according to the annular stress after the differentiation process.

[0071] The processor may determine the pipeline cross-sectional area of ​​the pipeline according to the pressure. Specifically, the processor may determine the strain of the pipeline according to the pressure. After determining the strain of the pipeline, the processor may determine the annular stress of the pipeline according to the strain, and perform a derivative process on the annular stress. After performing a derivative process on the annular stress, the processor may determine the pipeline cross-sectional area according to the annular stress after the derivative process.

[0072] For example, the processor can determine the strain ∈ of the pipeline according to the pressure on the pipeline. After determining the strain ∈ of the pipeline, the processor can calculate the linear elastic relationship between stress and strain based on the linear elastic relationship between stress and strain. Determine the hoop stress σ2, that is Where μ represents Poisson's ratio, σ1 represents axial stress, E represents Young's modulus, e represents pipe wall thickness, p represents pressure, and D represents pipe diameter. Pressure p is determined based on pressure. After obtaining the hoop stress σ2, the processor can perform derivative processing on the hoop stress to obtain the derived hoop stress Based on the linear elastic relationship between stress and strain, the differentiated hoop stress can be determined as The processor can further process the derived hoop stress based on the strain to determine The processor can be based on the relationship between the time change rate of the pipe cross-sectional area and the time change rate of the pressure. Determine the pipeline cross-sectional area of ​​the pipeline, where A represents the pipeline cross-sectional area.

[0073] After obtaining the pipeline cross-sectional area, the processor can determine the pipeline elasticity based on the pipeline cross-sectional area. After obtaining the pipeline elasticity, the processor can determine the influence of the pipeline elasticity on the wave velocity of the multiphase flow in the pipeline. The influence of the pipeline elasticity on the wave velocity of the multiphase flow can be expressed by the expression It indicates that, δ is the pipe wall thickness, v P is Poisson's coefficient, ρ0 is the multiphase flow density, d is the inner diameter of the pipe, E is Young's modulus, In order to consider the wave velocity of pipeline elasticity, a0 does not consider the wave velocity of pipeline elasticity. When the Young's modulus E is 100GPa, the processor can determine that the wave velocity considering pipeline elasticity is 1280m / s, and the wave velocity not considering pipeline elasticity is 1440m / s. It can be determined that the water thermal model considering pipeline elasticity can more realistically reflect the pipeline operation status and is more suitable for practical applications.

[0074] In an embodiment of the present application, the processor can determine the unsteady multiphase flow model of the pipeline in production through the BN multiphase flow model. Among them, the unsteady multiphase flow model includes a mass balance equation, a momentum balance equation, an energy balance equation, and a volume fraction evolution equation. The expression of the mass balance equation can be: The momentum balance equation can be expressed as:

[0075] The energy balance equation can be expressed as:

[0076]

[0077] The expression of the volume fraction evolution equation can be: Among them, α k is the volume fraction of medium k in the pipeline, ρ k is the density of the medium k in the pipeline, u k is the velocity of the medium k in the multi-pipe, C k is the chemical relaxation of the medium k in the pipeline, p k is the pressure of the medium k in the pipeline, is the phase correlation parameter, which is a constant. is the viscous stress tensor of the medium k in the pipeline, N is a positive integer, is the indirect influence pressure from the kth component of medium l to the Ith component, α l is the volume fraction of the lth medium, is the stress tensor from the kth component to the Ith component of medium l, is the chemical relaxation of the medium k in the pipeline, u I is the velocity of medium I, is the velocity relaxation of the medium k in the pipeline, E k is the energy of the medium k in the pipeline, q k is the heat flow of the medium k in the pipeline, is the velocity propagation coefficient of the lth component, is the density of the first component of medium I, is the energy relaxation of the medium k in the pipeline, Q k is the temperature relaxation of the medium k in the pipeline, is the heat flux from the kth component to the Ith component of medium l, is the pressure relaxation of the medium k in the pipeline, is the density of the th component of medium I, and t is the time.

[0078] In order to determine the influence of pipeline elasticity on the wave velocity of multiphase flow fluid in the pipeline, the processor can obtain the pressure on the pipeline and determine the cross-sectional area of ​​the pipeline according to the pressure. The processor can determine the pipeline elasticity of the pipeline according to the cross-sectional area of ​​the pipeline.

[0079] Specifically, the processor can determine the strain ∈ of the pipeline according to the pressure on the pipeline. After determining the strain ∈ of the pipeline, the processor can calculate the linear elastic relationship between stress and strain based on the linear elastic relationship between stress and strain. Determine the hoop stress σ2, that is Where μ represents Poisson's ratio, σ1 represents axial stress, E represents Young's modulus, e represents pipe wall thickness, p represents pressure, and D represents pipe diameter. Pressure p is determined based on pressure. After obtaining the hoop stress σ2, the processor can perform derivative processing on the hoop stress to obtain the derived hoop stress Based on the linear elastic relationship between stress and strain, the differentiated hoop stress can be determined as The processor can further process the derived hoop stress based on the strain to determine The processor can be based on the relationship between the time change rate of the pipe cross-sectional area and the time change rate of the pressure. Determine the pipeline cross-sectional area of ​​the pipeline, where A represents the pipeline cross-sectional area.

[0080] After obtaining the pipeline cross-sectional area, the processor can determine the pipeline elasticity based on the pipeline cross-sectional area. After obtaining the pipeline elasticity, the processor can determine the influence of the pipeline elasticity on the wave velocity of the multiphase flow in the pipeline. The influence of the pipeline elasticity on the wave velocity of the multiphase flow can be expressed by the expression It indicates that, δ is the pipe wall thickness, v P is Poisson's coefficient, ρ0 is the multiphase flow density, d is the inner diameter of the pipe, E is Young's modulus, In order to consider the wave velocity of pipeline elasticity, a0 does not consider the wave velocity of pipeline elasticity. When the Young's modulus E is 100 GPa, the processor can determine that the wave velocity considering pipeline elasticity is 1280 m / s, and the wave velocity not considering pipeline elasticity is 1440 m / s.

[0081] The processor can also determine the pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline. And determine the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow rate of the multiphase flow, so as to take into account the influence of non-steady-state friction resistance, reduce the deviation caused by the pressure wave and the velocity, and improve reliability. Specifically, the wall friction can be calculated according to formula (3):

[0082]

[0083] Among them, τ wu represents the wall friction, ρ represents the density of the multiphase flow, d represents the inner diameter of the pipeline, k t represents the dynamic viscosity of the multiphase flow, k x represents the thermal conductivity of multiphase flow, u is the fluid flow rate, a is the pressure wave velocity, t represents time, and x represents the spatial coordinate.

[0084] The processor may also determine that the multiphase flow in the pipeline includes multiple flow patterns. Figure 2 As shown, the multiphase flow may include a gas phase fluid and a liquid phase fluid. The processor may determine the flow types including stratified flow, wavy flow, annular flow, slug flow, bubble flow, dispersed flow and plug flow according to the flow rates of the gas phase fluid and the liquid phase fluid.

[0085] After determining the flow pattern, the processor can determine the interphase friction of the multiphase flow according to the flow pattern. Specifically, the interphase friction can be calculated according to formula (4):

[0086]

[0087] Among them, τ i represents the interphase friction, f i represents the friction coefficient of the i-th phase, α i represents the interphase surface integral ratio, ρ i represents the density of phase i fluid, v i is the relative speed.

[0088] In the case of all liquid phase fluids, the processor can Determine the fluid friction force τ wL Among them, α L is the liquid surface integral rate, f wL is the liquid phase friction coefficient, ρ L is the liquid density, v L is the liquid phase flow rate.

[0089] In the case of gas phase fluids, the processor can Determine the gas phase friction τ wg Among them, α g is the gas phase surface integral rate, f wg is the gas phase friction coefficient, ρ g is the gas phase density, v g is the gas phase flow rate.

[0090] The pipeline includes an inner wall, an insulation layer, and an outer wall. The pipeline parameters include at least a first heat transfer coefficient from the pipe flow in the pipeline to the inner wall, a heat transfer coefficient of the insulation layer, a second heat transfer coefficient from the outer wall of the pipeline to the soil, an inner diameter of the pipeline, an inner diameter of the insulation layer, an outer diameter of the insulation layer, and an outermost diameter of the pipeline. Determining the heat transfer coefficient of the pipeline according to the pipeline parameters includes calculating the heat transfer coefficient according to formula (5):

[0091]

[0092] Where K represents the heat transfer coefficient, α1 represents the first heat release coefficient, D1 represents the inner diameter of the pipe, and λ i Denotes the thermal conductivity, D i Indicates the inner diameter of the insulation layer, D (i+1) represents the outer diameter of the insulation layer, α2 represents the second heat release coefficient, D w represents the outermost diameter, and D represents the average of the inner diameter of the insulation layer and the outer diameter of the insulation layer.

[0093] After determining the unsteady multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient, the processor can construct a hydrothermal model based on the unsteady multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient to perform hydrothermal risk assessment of the pipeline.

[0094] like Figure 3 As shown in the figure, during the process of pipeline stopping, the heat dissipation of the pipeline causes the soil temperature near the outer wall of the pipe to rise, which is higher than the far-field soil temperature. At this time, the pipeline is radially (L x , L y ) cross section, and obtain the diameter d of the soil. In addition, the atmospheric temperature in the frozen soil area is low, which will also affect the soil temperature field and the temperature of the fluid in the pipeline. In order to determine the impact of the environment on the water and heat of the pipeline, the processor can also obtain the soil temperature and thermal conductivity of the soil where the pipeline is located, and determine the heat conduction equation of the soil heat conduction process in two-dimensional space. Among them, the heat conduction equation is shown in expression (1):

[0095]

[0096] Where T is the soil temperature, λ is the thermal conductivity, t is the time, and x and y are the spatial coordinates.

[0097] The processor can also obtain the fluid parameters of the multiphase flow, and determine the temperature drop equation of the multiphase flow in one-dimensional space according to the fluid parameters and the pipeline parameters. The temperature drop equation is shown in expression (2):

[0098]

[0099] Among them, α k represents the volume fraction of multiphase flow included in the fluid parameters, ρ k represents the density of multiphase flow including fluid parameters, E k represents the energy of the multiphase flow included in the fluid parameters, A represents the pipe cross-sectional area of ​​the pipe included in the pipe parameters, d represents the diameter of the pipe included in the pipe parameters, T0 represents the initial temperature of the multiphase flow, and π represents the circumference of a circle.

[0100] The processor can construct a pipe-soil coupled temperature drop model of the pipeline based on the heat conduction equation and the temperature drop equation to realize the hydrothermal analysis of the pipeline in the frozen soil low temperature and large drop environment.

[0101] Through the above technical solution, a more complete hydrothermal model for pipeline commissioning can be constructed, and the hydrothermal model comprehensively considers the non-steady-state multiphase flow, pipeline elasticity, friction and heat transfer capacity of the pipeline, making the constructed hydrothermal model more accurate and reducing the deviation caused by factors such as friction. It can better analyze the hydrothermal risks of pipeline commissioning and has higher practicality.

[0102] Figure 1 FIG. 1 is a flow chart of a method for constructing a multiphase flow water thermal model for pipeline commissioning in one embodiment. It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0103] An embodiment of the present application provides a processor, which is used to run a program, wherein the program executes the method for constructing the multiphase flow water thermal model of the pipeline commissioning when running.

[0104] An embodiment of the present application provides a device for constructing a multiphase flow water thermal model for pipeline commissioning, including the above-mentioned processor.

[0105] An embodiment of the present application provides a storage medium on which a program is stored. When the program is executed by a processor, the method for constructing the multiphase flow water thermal model of the pipeline commissioning is implemented.

[0106] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 4As shown. The computer device includes a processor A01, a network interface A02, a memory (not shown in the figure) and a database (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02 and a database (not shown in the figure). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database of the computer device is used to store data on pressure, pipeline cross-sectional area, fluid density, pressure wave velocity, wall friction, phase friction and heat transfer coefficient. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program B02 is executed by the processor A01, a method for constructing a multiphase flow water thermal model for pipeline commissioning is implemented.

[0107] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0108] An embodiment of the present application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: determining a non-steady-state multiphase flow model of a pipeline during production through a BN multiphase flow model; obtaining the pressure on the pipeline, and determining the pipeline cross-sectional area of ​​the pipeline according to the pressure; determining the pipeline elasticity of the pipeline according to the pipeline cross-sectional area; determining the pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline; determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow rate of the multiphase flow; determining multiple flow types included in the multiphase flow of the pipeline, and determining the phase friction of the multiphase flow according to the multiple flow types; determining the heat transfer coefficient of the pipeline according to the pipeline parameters of the pipeline; and constructing a hydrothermal model according to the non-steady-state multiphase flow model, pipeline elasticity, wall friction, phase friction, and heat transfer coefficient.

[0109] In one embodiment, the construction method also includes: after constructing a hydrothermal model based on a non-steady-state multiphase flow model, pipeline elasticity, wall friction, interphase friction, and heat transfer coefficient, obtaining the soil temperature and thermal conductivity of the soil in which the pipeline is located; determining the heat conduction equation of the soil in two-dimensional space based on the soil temperature and thermal conductivity; obtaining the fluid parameters of the multiphase flow, and determining the temperature drop equation of the multiphase flow in one-dimensional space based on the fluid parameters and the pipeline parameters; and constructing a pipe-soil coupled temperature drop model of the pipeline based on the heat conduction equation and the temperature drop equation.

[0110] In one embodiment, the heat conduction equation is as shown in expression (1):

[0111]

[0112] Where T is soil temperature, λ is thermal conductivity, t is time, and x and y are spatial coordinates;

[0113] The temperature drop equation is shown in expression (2):

[0114]

[0115] Among them, α k represents the volume fraction of multiphase flow included in the fluid parameters, ρ k represents the density of multiphase flow including fluid parameters, E k represents the energy of the multiphase flow included in the fluid parameters, A represents the pipe cross-sectional area of ​​the pipe included in the pipe parameters, d represents the diameter of the pipe included in the pipe parameters, T0 represents the initial temperature of the multiphase flow, and π represents the circumference of a circle.

[0116] In one embodiment, determining the cross-sectional area of ​​the pipeline according to the pressure includes: determining the strain of the pipeline according to the pressure; determining the annular stress of the pipeline according to the strain, and performing a derivative processing on the annular stress; and determining the cross-sectional area of ​​the pipeline according to the annular stress after the derivative processing.

[0117] In one embodiment, determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow velocity of the multiphase flow includes calculating the wall friction according to formula (3):

[0118]

[0119] Among them, τ wu represents the wall friction, ρ represents the density of the multiphase flow, d represents the inner diameter of the pipeline, k t represents the dynamic viscosity of the multiphase flow, k x represents the thermal conductivity of multiphase flow, u is the fluid flow rate, a is the pressure wave velocity, t represents time, and x represents the spatial coordinate.

[0120] In one embodiment, determining the interphase friction of the multiphase flow according to the plurality of flow patterns includes calculating the interphase friction according to formula (4):

[0121]

[0122] Among them, τ i represents the interphase friction, f i represents the friction coefficient of the i-th phase, α i represents the interphase surface integral ratio, ρi represents the density of phase i fluid, v i is the relative speed.

[0123] In one embodiment, the pipeline includes an inner wall, an insulation layer, and an outer wall. The pipeline parameters include at least a first heat release coefficient from the pipe flow in the pipeline to the inner wall, a heat transfer coefficient of the insulation layer, a second heat release coefficient from the outer wall of the pipeline to the soil, an inner diameter of the pipeline, an inner diameter of the insulation layer, an outer diameter of the insulation layer, and an outermost diameter of the pipeline. Determining the heat transfer coefficient of the pipeline according to the pipeline parameters includes calculating the heat transfer coefficient according to formula (5):

[0124]

[0125] Where K represents the heat transfer coefficient, α1 represents the first heat release coefficient, D1 represents the inner diameter of the pipe, and λ i Denotes the thermal conductivity, D i Indicates the inner diameter of the insulation layer, D (i+1) represents the outer diameter of the insulation layer, α2 represents the second heat release coefficient, D w represents the outermost diameter, and D represents the average of the inner diameter of the insulation layer and the outer diameter of the insulation layer.

[0126] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing the program steps of the method for initializing the construction of a multiphase flow water thermal model for pipeline commissioning.

[0127] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0128] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0129] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0130] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0131] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0132] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0133] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0134] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, 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 process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0135] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for constructing a multiphase flow water thermal model for pipeline commissioning, characterized in that: The construction method comprises: Determine the unsteady multiphase flow model of the pipeline during production by using the BN multiphase flow model; Obtaining the pressure on the pipeline, and determining the pipeline cross-sectional area of ​​the pipeline according to the pressure; determining the pipeline elasticity of the pipeline according to the cross-sectional area of ​​the pipeline; determining a pressure wave velocity in the pipeline according to the pressure and the fluid density of the multiphase flow in the pipeline; determining a wall friction force between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow velocity of the multiphase flow; Determine a plurality of flow patterns included in the multiphase flow of the pipeline, and determine the interphase friction of the multiphase flow according to the plurality of flow patterns; determining a heat transfer coefficient of the pipeline according to pipeline parameters of the pipeline; Constructing the water thermal model according to the unsteady multiphase flow model, the pipeline elasticity, the wall friction, the interphase friction and the heat transfer coefficient; The construction method further comprises: After constructing the water thermal model according to the unsteady multiphase flow model, the pipeline elasticity, the wall friction, the interphase friction and the heat transfer coefficient, obtaining the soil temperature and thermal conductivity of the soil where the pipeline is located; Determine the heat conduction equation of the soil in two-dimensional space according to the soil temperature and the thermal conductivity; Acquiring fluid parameters of the multiphase flow, and determining a temperature drop equation of the multiphase flow in one-dimensional space according to the fluid parameters and the pipeline parameters; A pipe-soil coupled temperature drop model of the pipeline is constructed according to the heat conduction equation and the temperature drop equation.

2. The method for constructing a multiphase flow water thermal model for pipeline commissioning according to claim 1, characterized in that: The heat conduction equation is shown in expression (1): Wherein, T is the soil temperature, λ represents the thermal conductivity, t represents time, and x and y represent spatial coordinates; The temperature drop equation is shown in expression (2): Among them, α k represents the volume fraction of the multiphase flow included in the fluid parameters, ρ k represents the density of the multiphase flow including the fluid parameters, E k represents the energy of the multiphase flow included in the fluid parameters, A represents the pipe cross-sectional area of ​​the pipe included in the pipe parameters, d represents the diameter of the pipe included in the pipe parameters, T0 represents the initial temperature of the multiphase flow, and π represents pi.

3. The method for constructing a multiphase flow water thermal model for pipeline commissioning according to claim 1, characterized in that: Determining the pipeline cross-sectional area of ​​the pipeline according to the pressure includes: determining a strain of the pipeline based on the pressure; Determining the hoop stress of the pipeline according to the strain, and performing a derivative process on the hoop stress; The cross-sectional area of ​​the pipeline is determined according to the annular stress after derivation.

4. The method for constructing a multiphase flow water thermal model for pipeline commissioning according to claim 1, characterized in that: Determining the wall friction between the pipeline and the multiphase flow according to the pressure wave velocity and the fluid flow velocity of the multiphase flow includes calculating the wall friction according to formula (3): Among them, τ wu represents the wall friction, ρ represents the density of the multiphase flow, d represents the inner diameter of the pipeline, k t represents the dynamic viscosity of the multiphase flow, k x represents the thermal conductivity of the multiphase flow, u is the fluid flow rate, a is the pressure wave velocity, t represents time, and x represents the spatial coordinate.

5. The method for constructing a multiphase flow water thermal model for pipeline commissioning according to claim 1, characterized in that: Determining the interphase friction of the multiphase flow according to the multiple flow patterns includes calculating the interphase friction according to formula (4): Among them, the τ i represents the interphase friction force, f i represents the friction coefficient of the i-th phase, α i represents the interphase surface integral ratio, ρ i represents the density of phase i fluid, v i is the relative speed.

6. The method for constructing a multiphase flow water thermal model for pipeline commissioning according to claim 1, characterized in that: The pipeline includes an inner wall, an insulation layer, and an outer wall. The pipeline parameters include at least a first heat transfer coefficient from the pipe flow in the pipeline to the inner wall, a heat transfer coefficient of the insulation layer, a second heat transfer coefficient from the outer wall of the pipeline to the soil, an inner diameter of the pipeline, an inner diameter of the insulation layer, an outer diameter of the insulation layer, and an outermost diameter of the pipeline. Determining the heat transfer coefficient of the pipeline according to the pipeline parameters includes calculating the heat transfer coefficient according to formula (5): Wherein, K represents the heat transfer coefficient, α1 represents the first heat release coefficient, D1 represents the inner diameter of the pipe, λ i Denotes the thermal conductivity, D i Indicates the inner diameter of the insulation layer, D (i+1) represents the outer diameter of the thermal insulation layer, α2 represents the second heat release coefficient, D w represents the outermost diameter, and D represents the average of the inner diameter of the thermal insulation layer and the outer diameter of the thermal insulation layer.

7. A processor, characterized in that: The method is configured to execute the method for constructing a multiphase flow water thermal model for pipeline commissioning according to any one of claims 1 to 6.

8. A device for constructing a multiphase flow water thermal model for pipeline commissioning, characterized in that: The constructing means comprises a processor according to claim 7.

9. A machine-readable storage medium having instructions stored thereon, characterized in that: When the instruction is executed by a processor, the processor is configured to execute the method for constructing a multiphase flow water thermal model for pipeline commissioning according to any one of claims 1 to 6.

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