A wind turbine concrete foundation hydration heat cold water pipe temperature control method and system

Abstract

The application relates to the technical field of wind power generation, and discloses a wind turbine concrete foundation hydration heat cold water pipe temperature control method and system. The temperature control method is combined with the distribution law of the hydration heat temperature field of the large-volume concrete foundation of the wind turbine, a temperature field calculation model of the cold water pipe temperature control is constructed based on a numerical heat conduction theory method, and the interval parameter of the cold water pipe is determined. The application solves the problems of large modeling workload and low calculation efficiency in the prior art.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically a method and system for controlling the temperature of the hydration hot and cold water pipes in the concrete foundation of a wind turbine. Background Technology

[0002] Wind farms are typically located in high-altitude, frigid regions. The construction of wind turbine foundations, under low-temperature conditions, is a critical stage in the overall project, involving the construction of large-volume concrete under these conditions. During pouring, the heat of hydration generates a significant amount of heat within the structure. This causes the internal temperature of the concrete to rise, leading to cracks during plastic shrinkage and hardening. Complex temperature and temperature stress variations within the structure result in uneven concrete shrinkage, causing localized cracking, which can severely impact the structure's safety, reliability, and durability. Therefore, controlling the heat of hydration during the construction phase of large-volume concrete wind turbine foundations has significant theoretical and engineering value.

[0003] Extensive research and analysis by scholars both domestically and internationally have been conducted on the heat of hydration in large-volume concrete, leading to the proposal of numerous measures to prevent temperature cracks. These measures include layered / block pouring during construction, real-time monitoring of the internal temperature field, use of low-heat-of-hydration cement, installation of cooling water pipe systems within the structure, and the use of low-temperature fluids for heat dissipation. Among these, cooling water pipes have become the primary cooling measure for reducing the heat of hydration in large-volume concrete due to their high reliability, sustainability, and economic efficiency. Therefore, it is crucial to investigate the impact of relevant parameters of cooling water pipes on the cooling effect of the heat of hydration in wind turbine foundation concrete, considering the distribution pattern of the temperature field.

[0004] Research on temperature control of cooling water pipes for hydration heat in large-volume concrete indicates that a cross-shaped arrangement is optimal due to significant convective heat transfer. However, the spacing between cooling water pipes is a crucial factor affecting their effectiveness. Therefore, determining the optimal spacing is a new and pressing issue concerning the hydration heat of concrete cooling water pipes. Current analytical methods primarily rely on finite element models, often determining the optimal spacing through iterative calculations. However, this modeling process is extremely labor-intensive and unsuitable for simplifying the initial design of pipe spacing, resulting in low computational efficiency. To address these issues, this paper proposes a method for temperature control and spacing parameter design of cooling water pipes for hydration heat in large-volume concrete foundations, based on numerical heat conduction theory and the specific structure of the hydration heat of large-volume concrete cooling water pipes. The paper also analyzes the temperature control effect and constructs an analytical calculation method for cooling water pipe spacing, providing methodological support for research on temperature control of cooling water pipes for hydration heat in large-volume concrete. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a method and system for temperature control of hydration hot and cold water pipes in concrete foundations of wind turbine units, solving problems such as large modeling workload and low computational efficiency in existing technologies.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A method for controlling the temperature of cooling water pipes in the hydration heat of wind turbine concrete foundations is proposed. This method combines the distribution law of the hydration heat temperature field of large-volume concrete foundations of wind turbines with numerical heat conduction theory to construct a temperature field calculation model for cooling water pipe temperature control and determine the spacing parameters of the cooling water pipes.

[0008] As a preferred technical solution, the steps include:

[0009] S1, Construct an equivalent heat conduction model: Construct a heat conduction model of the temperature field of the cold water pipe, and regard the temperature field of the cooling water pipe as a spatially unstable temperature field of the internal cooling source.

[0010] S2: Construct a temperature field calculation model: Treat the distance between cold water pipes as the distance between adjacent nodes in the heat conduction model, establish a temperature field calculation model that includes the distance between cold water pipes, and convert the calculation of the temperature field of the cooling water pipes into solving the temperature field calculation model of the spatially unstable temperature field under given initial and boundary conditions.

[0011] S3, Calculate node temperature: Discretize the calculation region of the temperature field calculation model containing the spacing of cold water pipes established in step S2 into a grid using the finite volume method, and calculate the temperature of the boundary nodes of the grid in the discretized region and the temperature of the intermediate interpolation nodes.

[0012] S4, Calculate the cold water pipe spacing parameters: Based on the temperature of the grid boundary nodes and the temperature of the intermediate interpolation nodes calculated in step S3, jointly determine the optimal spacing parameters of the cold water pipes.

[0013] As a preferred technical solution, in step S1, the analytical calculation formula for the cooling of the large-volume concrete cold water pipe is as follows:

[0014]

[0015] In the formula, k is the thermal conductivity, T is the temperature, S is the heat generation rate per unit volume, and dx is the distance between two adjacent temperature calculation nodes.

[0016] Equation (1) can be expressed as:

[0017] S = S C +S P T P (2)

[0018] In the formula, S C S is the constant part of S.P Let P be a function of temperature T, and let T represent a generalized node. P The temperature of node P is calculated.

[0019] As a preferred technical solution, in step S3, the formula for calculating the temperature field including the spacing between the cold water pipes is as follows:

[0020] a P T P =a E T E +a W T W +b (5)

[0021] In the formula, the undetermined coefficient a E a W a P b is:

[0022]

[0023] In this context, node P considers grid nodes E and W as its two adjacent nodes, with node E representing the downstream direction and node W representing the upstream direction. The letter 'e' represents the downstream interface of node P, the letter 'w' represents the upstream interface of node P, Δx represents the distance between the downstream and upstream interfaces, and δx represents the distance between the downstream and upstream nodes. (δx) e Let (δx) represent the distance from node E to node P. w a represents the distance from node W to node P. E a W a P b are undetermined coefficients, and T p Let T be the temperature of node P in the temperature calculation. E Let T be the temperature of node E. W Let T be the temperature at node W, h be the heat transfer coefficient, and T be the temperature at node W. f The ambient temperature.

[0024] As a preferred technical solution, for the starting or ending node of the computation region, the undetermined coefficient 'a' W a P And b is represented as:

[0025]

[0026] As a preferred technical solution, in step S3, the node temperature relationship of node T0 satisfies:

[0027] T0 = ​​t0 (9)

[0028] In the formula, T0 is the node temperature at the location of the cold water pipe, and t0 is the temperature of the cooling water in the cold water pipe;

[0029] The temperature relationship at node T1 is as follows:

[0030]

[0031] In the formula, T1 is the interpolation node temperature and T2 is the boundary node temperature.

[0032] As a preferred technical solution, in step S3, the temperature relationship at node T2 is as follows:

[0033]

[0034] As a preferred technical solution, in step S4:

[0035]

[0036] In the formula, Δx1 and Δx2 are the two roots of equation (13), h is the heat release coefficient, and T is the heat release coefficient. f The ambient temperature.

[0037] As a preferred technical solution, the spacing between the cold water pipes in formula (17) satisfies the following conditions:

[0038]

[0039]

[0040] In the formula, Δl is the spacing between the cooling water pipes.

[0041] A temperature control system for the hydration hot and cold water pipes of a wind turbine concrete foundation, based on the aforementioned method for controlling the temperature of the hydration hot and cold water pipes of a wind turbine concrete foundation, includes the following modules connected in sequence:

[0042] Equivalent heat conduction model construction module: used to construct a heat conduction model of the temperature field of the cold water pipe, treating the temperature field of the cooling water pipe as a spatially unstable temperature field of the internal cooling source.

[0043] Temperature field calculation model construction module: It is used to regard the distance between cold water pipes as the distance between adjacent nodes in the heat conduction model, establish a temperature field calculation model including the distance between cold water pipes, and convert the calculation of the temperature field of the cooling water pipes into solving the temperature field calculation model of the spatially unstable temperature field under given initial and boundary conditions.

[0044] Node temperature calculation module: used to discretize the calculation region of the temperature field calculation model containing the spacing between cold water pipes into a grid using the finite volume method, and calculate the temperature of the boundary nodes of the discretized region grid and the temperature of the intermediate interpolation nodes.

[0045] Cold water pipe spacing parameter calculation module: used to jointly determine the optimal spacing parameters of cold water pipes based on the temperature of the grid boundary nodes and the temperature of the intermediate interpolation nodes.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] This invention combines the distribution law of the hydration heat temperature field of wind turbine foundation concrete, and constructs a theoretical mathematical calculation model of the temperature field of chilled water pipe temperature control based on numerical heat conduction theory, to determine the design method and installation method of its spacing parameters. This invention is simple and easy to implement, and its reliability has been verified by examples and data, showing good application prospects. Attached Figure Description

[0048] Figure 1 This is a cross-sectional view of the large-volume concrete cooling water pipe of the wind turbine foundation in an embodiment of the present invention;

[0049] Figure 2 yes Figure 1 A longitudinal sectional view;

[0050] Figure 3 This is the computational grid for a one-dimensional problem in an embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of the cold water pipe temperature node in an embodiment of the present invention;

[0052] Figure 5 This is a schematic diagram illustrating the steps of a method for controlling the temperature of the hydration hot and cold water pipes in a concrete foundation for a wind turbine, as described in this invention.

[0053] The attached diagram shows the markings and corresponding component names: 1. Concrete, 2. Cold water pipe. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0055] Example 1

[0056] like Figures 1 to 5As shown, this invention, combining the layout of intersecting cooling water pipes and based on numerical heat conduction theory, constructs a mathematical model of the temperature control field for the hydration heat and cold water pipes of large-volume concrete in wind turbine foundations. Based on the finite volume numerical calculation method, a design method for the temperature control spacing parameters of the hydration heat and cold water pipes in large-volume concrete of wind turbine foundations is proposed. This includes the following steps: Step 1): Equivalently representing the temperature control field of the hydration heat and cold water pipes of large-volume concrete in wind turbine foundations as a heat conduction mathematical model; Step 2): Establishing a mathematical model of the temperature field of the cold water pipe spacing; Step 3): Calculating the temperature of each discrete and interpolation node; Step 4): Calculating the cold water pipe spacing parameters. This invention, by determining the optimal spacing of the cold water pipes, has significant theoretical and engineering value for promoting environmentally friendly and energy-saving green construction and for the temperature control of the hydration heat and cold water pipes in large-volume concrete.

[0057] Includes the following steps:

[0058] Step 1: Equivalently model the temperature control field of the hydration heat and cold water pipes of the large-volume concrete foundation of the wind turbine unit as a heat conduction mathematical model.

[0059] Given the temperature distribution of large-volume concrete from the inside out, which gradually decreases, the cross-arrangement of cooling water pipes has become increasingly popular in the engineering industry due to its significant convective heat transfer effect, ease of implementation, and superior economic performance. It is now the most widely used method in the industry, and its planar layout is as follows: Figure 1 .

[0060] The cross-section of the cold water pipe 2 in the large-volume concrete 1 is as follows: Figure 2 The spacing between the water pipes is denoted as Δl. Cold water pipe 2 is considered as a cooling source, and the optimal cooling effect is achieved when the cooling effect between the two rows of cold water pipes 2 reaches half the temperature of the concrete center. The temperature field of the cooling water pipes can be regarded as the spatially unstable temperature field of the internal cooling source, and its temperature field calculation is the solution of the heat conduction equation of the spatially unstable temperature field under given initial and boundary conditions.

[0061] according to Figure 2 Based on a simplified mathematical model and the one-dimensional steady-state heat conduction theory, the analysis and calculation of cooling of the cold water pipe in a large-volume concrete structure can be expressed as follows:

[0062]

[0063] In the formula, k is the thermal conductivity, T is the temperature, and S is the heat generation rate per unit volume, which can be expressed as:

[0064] S = S C +S P T P (2)

[0065] In the formula, S C S is the constant part of S. P It is a function that varies with temperature T.

[0066] Step 2: Establish a mathematical model of the temperature field between the cold water pipes.

[0067] Will Figure 2 The distance between the two cold water pipes 2 is half of the discretization. Figure 3 The grid node group in the middle, Figure 3 In the diagram, P represents a generalized node, which considers grid nodes E and W as its two neighbors (E is downstream, i.e., in the positive direction of the coordinate axis; and W is upstream, i.e., in the negative direction of the coordinate axis). The control volume corresponding to each node is also represented by the same character. The upstream and downstream interfaces of node P are represented by the letters e and w, respectively, and the dashed lines represent the control volume surfaces. The distance between the two interfaces is represented by Δx, and the distance from point E to node P is represented by (δx). e Let (δx) represent the distance from point W to node P. w express.

[0068] Combination Figure 3 From formula (1), the integral of the control volume yields...

[0069]

[0070] By using a piecewise linear distribution to calculate dT / dx in formula (3), we can obtain

[0071]

[0072] In the formula, the subscripts W and w represent the upstream node of the control volume, E and e represent the downstream node of the control volume, Δx represents the distance between the two interfaces, and δx represents the distance between the two nodes.

[0073] For convenience, the discretization equation (4) is rewritten as follows:

[0074] a P T P =a E T E +a W T W +b (5)

[0075] In the formula, the undetermined coefficient a E a W a P b can be represented as

[0076]

[0077] For the boundary nodes, the discretized equation (4) can be rewritten as follows:

[0078] a P T P =a W TW +b (7)

[0079] In the formula, the undetermined coefficient a W a P And b can be represented as

[0080]

[0081] In the formula, h is the heat release coefficient, and T f The ambient temperature.

[0082] Step 3: Calculate the temperature of each discrete and interpolated node.

[0083] Since cold water pipe 2 is considered an equivalent cooling source, and the optimal cooling effect between the two rows of cold water pipes 2 is half the temperature of the concrete center, therefore, [the following is taken as the optimal value]. Figure 2 The locations of the intermediate cooling water pipes (denoted as T0) and the center of the two cooling water pipes (denoted as T2) are the calculation temperature nodes, and T1 is the interpolation node temperature, which is discretized into... Figure 4 The three temperature nodes are shown.

[0084] for Figure 4 The nodal temperature relationship of node T0 in the equation satisfies

[0085] T0 = ​​t0 (9)

[0086] In the formula, t0 is the temperature of the cooling water in the cold water pipe 2.

[0087] for Figure 4 For node T1 in the equation (6), the undetermined coefficient a E a W a P And b can be represented as

[0088]

[0089] Substituting into formula (5), we can obtain the temperature relationship at node T1.

[0090]

[0091] for Figure 4 The node T2 in the equation is a boundary node (i.e., the node at the center of the two cold water pipes). The node temperature is determined by formula (8), with an undetermined coefficient a. W a P And b can be represented as

[0092]

[0093] Substituting into formula (7), we can obtain the temperature relationship at node T2.

[0094]

[0095] Step 4: Calculate the cold water pipe spacing parameters.

[0096] according to Figure 2 and Figure 3 The geometric relationship, the relationship between the cold water pipe spacing and the interface distance Δx is as follows:

[0097]

[0098] Cold water pipe 2 is considered an equivalent cooling source, and the optimal cooling effect between the two rows of cold water pipes 2 is achieved when the temperature reaches half the core temperature of the concrete.

[0099]

[0100] Combining formulas (9), (11), and (13) to (15), we can obtain

[0101] SΔl 2 +(4hT f -2hT0)Δl+4kt0=0 (16)

[0102] By solving formula (16), the spacing between the cold water pipes can be obtained as follows:

[0103]

[0104] Finally, considering both the effectiveness and economic principles of the solution in formula (17), the spacing between cold water pipes must meet the following conditions.

[0105]

[0106] This invention provides a practical and feasible specific structure for the hydration heat of large-volume concrete cooling water pipes. Based on numerical heat conduction theory, it equates the temperature control field of the hydration heat of large-volume concrete cooling water pipes in wind turbine foundations to a heat conduction mathematical model, and establishes a mathematical model of the temperature field between the cooling water pipes. The temperature of each discrete and interpolated node is calculated, and an analytical calculation method for the spacing of the cooling water pipes is constructed. This has significant theoretical and engineering value for promoting environmentally friendly and energy-saving green construction and for the temperature control of hydration heat in large-volume concrete cooling water pipes.

[0107] Given the temperature distribution of large-volume concrete from the inside out to the bottom, the cross-arrangement of cooling water pipes has become increasingly popular in the engineering industry due to its significant convective heat transfer effect, ease of implementation, and superior economic performance. It is now the most widely used method in the industry, and its planar layout is as follows: Figure 1 .

[0108] like Figure 5As shown, this invention describes the specific process of equating the temperature control field of the hydration heat and cold water pipes of the large-volume concrete foundation of the wind turbine with a heat conduction mathematical model.

[0109] like Figure 3 As shown, this invention provides a computational grid for a one-dimensional problem.

[0110] like Figure 4 The figure shows a schematic diagram of the cold water pipe temperature node of the present invention.

[0111] The design method for temperature control and spacing parameters of the hydration hot and cold water pipes of large-volume concrete for wind turbine foundations proposed in this invention has been verified for its correctness and rationality by finite element numerical simulation software.

[0112] In summary, this invention has significant theoretical and engineering value for promoting environmentally friendly and energy-saving green construction and for temperature control of hot and cold water pipes in the hydration of large-volume concrete.

[0113] As described above, the present invention can be implemented well.

[0114] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0115] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for temperature control of hydration heat and cold water pipes in the concrete foundation of a wind turbine, characterized in that, Based on the distribution law of the hydration heat temperature field of the large-volume concrete foundation of wind turbine, and using the numerical heat conduction theory method, a temperature field calculation model for the temperature control of the cold water pipe is constructed to determine the spacing parameters of the cold water pipe. Includes the following steps: S1, Construct an equivalent heat conduction model: Construct a heat conduction model of the temperature field of the cold water pipe, and regard the temperature field of the cooling water pipe as a spatially unstable temperature field of the internal cooling source. S2: Construct a temperature field calculation model: Treat the distance between cold water pipes as the distance between adjacent nodes in the heat conduction model, establish a temperature field calculation model that includes the distance between cold water pipes, and convert the calculation of the temperature field of the cooling water pipes into solving the temperature field calculation model of the spatially unstable temperature field under given initial and boundary conditions. S3, Calculate node temperature: Discretize the calculation region of the temperature field calculation model containing the spacing of cold water pipes established in step S2 into a grid using the finite volume method, and calculate the temperature of the boundary nodes of the grid in the discretized region and the temperature of the intermediate interpolation nodes. S4, Calculate the cold water pipe spacing parameters: Based on the temperature of the grid boundary nodes and the temperature of the intermediate interpolation nodes calculated in step S3, jointly determine the optimal spacing parameters of the cold water pipes; In step S3, the formula for calculating the temperature field, including the spacing between the cold water pipes, is as follows: （5） In the formula, the undetermined coefficients , , , for: （6） In this context, node P considers grid nodes E and W as its two adjacent nodes, with node E representing the downstream direction and node W representing the upstream direction. The letter 'e' represents the downstream interface of node P, and the letter 'w' represents the upstream interface of node P. This indicates the distance between the downstream interface and the upstream interface. This represents the distance between downstream and upstream nodes. This represents the distance from node E to node P. This represents the distance from node W to node P. , , , For undetermined coefficients, The temperature of node P is calculated. Let E be the temperature of node E. Let W be the temperature of node W. h The heat transfer coefficient, The ambient temperature.

2. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 1, characterized in that, In step S1, the analytical calculation formula for the cooling of the large-volume concrete cold water pipe is as follows: （1） In the formula, Thermal conductivity, For temperature, The heat generation rate per unit volume. This is the distance between two adjacent temperature calculation nodes; Equation (1) can be expressed as: （2） In the formula, for The constant part, As temperature A changing function, Represents a node in a generalized sense. Temperature calculation node The temperature.

3. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 2, characterized in that, For the starting or ending nodes of the computational domain, the coefficients to be determined , as well as It is represented as: （8）。 4. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 3, characterized in that, In step S3, The nodes, whose nodal temperature relationships satisfy: （9） In the formula, This refers to the node temperature at the location of the cold water pipe. The temperature of the cooling water in the cold water pipe; The temperature relationship of the nodes is as follows: （11） In the formula, For intermediate interpolation node temperatures, Temperature at the boundary node; The location of the cold water pipe is marked as The location at the center of the two cold water pipes is denoted as The locations of the cold water pipes and the center of the two cold water pipes are taken as the calculation temperature nodes. The interpolation node temperature.

5. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 4, characterized in that, In step S3, The temperature relationship of the nodes is as follows: （13）。 6. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 5, characterized in that, In step S4: （17） In the formula, and These are the two roots of equation (13). The heat transfer coefficient, The ambient temperature.

7. The method for temperature control of hydration hot and cold water pipes in the concrete foundation of a wind turbine according to claim 6, characterized in that, In formula (17), the spacing between cold water pipes must meet the following conditions: （14） （18） In the formula, This refers to the spacing between the cooling water pipes.

8. A temperature control system for the hydration hot and cold water pipes of a wind turbine concrete foundation, characterized in that, A method for temperature control of hydration hot and cold water pipes in concrete foundations of wind turbine units according to any one of claims 1 to 7, comprising the following modules connected in sequence: Equivalent heat conduction model construction module: used to construct a heat conduction model of the temperature field of the cold water pipe, treating the temperature field of the cooling water pipe as a spatially unstable temperature field of the internal cooling source. Temperature field calculation model construction module: It is used to regard the distance between cold water pipes as the distance between adjacent nodes in the heat conduction model, establish a temperature field calculation model including the distance between cold water pipes, and convert the calculation of the temperature field of the cooling water pipes into solving the temperature field calculation model of the spatially unstable temperature field under given initial and boundary conditions. Node temperature calculation module: used to discretize the calculation region of the temperature field calculation model containing the spacing between cold water pipes into a grid using the finite volume method, and calculate the temperature of the boundary nodes of the discretized region grid and the temperature of the intermediate interpolation nodes. Cold water pipe spacing parameter calculation module: used to jointly determine the optimal spacing parameters of cold water pipes based on the temperature of the grid boundary nodes and the temperature of the intermediate interpolation nodes.

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