A method for predicting a temperature field of a concrete containing a pipe

Abstract

The application discloses a kind of pipe-containing concrete temperature field prediction methods in the field of building construction technology, comprising: obtaining water pipe diameter;Virtual boundary is demarcated based on water pipe diameter and heat insulation condition is applied, and ring-shaped single pipe influence domain independent model is established;Based on the ring-shaped single pipe influence domain independent model, the local radial basis function is used to distribute points on the influence domain and construct a solving equation, and the temperature field near the pipe wall is obtained;Based on the temperature field near the pipe wall, equivalent function and equivalent parameters are introduced for calculation, and the equivalent temperature of the center is obtained;Based on the equivalent temperature of the center, the test area model is solved by self-correcting decoupling model;Based on the solving result, the temperature field of the test area is predicted.The application can save data reconstruction time and calculation cost, solve the problems of complex structure, large size ratio, grid or point optimization difficulty and slow convergence in the calculation process of the existing technology containing multiple water pipe concrete block temperature field.

Description

TECHNICAL FIELD

[0001] The application relates to a pipeline-containing concrete temperature field prediction method and belongs to the technical field of building construction. BACKGROUND

[0002] A large amount of hydration heat is generated in the pouring process of a large concrete structure, heat aggregation is prone to occur, internal high temperature generates tensile stress in the cooling process, thermal cracks are caused, and the safety and reliability of the structure are affected. Due to the large size ratio between the concrete structure and the slender pipeline, in order to accurately solve, a relatively dense grid or point distribution is required to describe the high temperature gradient heat transfer phenomenon near the pipeline wall. When the pipeline diameter, pipeline arrangement position and pipeline arrangement density and other design problems are involved, the grid or point distribution must be re-adjusted and optimized, causing difficulty in solving. Therefore, developing an applicable mathematical model to predict the temperature field of a concrete structure containing multiple water pipes has certain theoretical and engineering value.

[0003] Traditionally, the heat transfer calculation model of the concrete containing multiple water pipes includes an average equivalent mathematical model, a simplified single-water-pipe-containing model and an overall model adopting encrypted and locally optimized grids. The average equivalent mathematical model can be used for the overall structure temperature field analysis except for the temperature field near the pipeline wall and cannot accurately simulate the temperature field near the pipeline wall. The simplified single-water-pipe-containing model is a fine description of the local temperature field and lacks the description of the overall temperature field of the mass concrete and cannot reflect the influence of specific external factors. The overall model adopting encrypted and locally optimized grids can meet the precision requirements of engineering, but the storage and calculation amount occupied are huge, especially in the treatment of structures with small pipeline diameter and large size ratio, the thinner the pipeline, the more points are required and the higher the calculation cost, which seriously affects the calculation speed. SUMMARY

[0004] The application aims to overcome the deficiencies in the prior art and provide a pipeline-containing concrete temperature field prediction method, which can save data reconstruction time and calculation cost, solve the problems of complex structure, large size ratio, grid or point optimization difficulty and slow calculation convergence in the temperature field calculation process of the prior art concrete containing multiple water pipes.

[0005] To achieve the above-mentioned purpose, the application is implemented by using the following technical scheme:

[0006] In a first aspect, the application provides a pipeline-containing concrete temperature field prediction method, which comprises:

[0007] Obtaining the water pipe diameter;

[0008] Based on the water pipe diameter, a virtual boundary is demarcated and an adiabatic condition is applied to establish a ring-shaped single-pipe-influence-domain independent model;

[0009] Based on the ring-based single pipe influence domain independent model, the local radial basis function collocation method is used to collocate points on the influence domain and construct a solving equation to obtain the temperature field near the pipe wall;

[0010] Based on the temperature field near the pipe wall, an equivalent function and equivalent parameter are introduced for calculation to obtain the equivalent temperature of the circle center;

[0011] Based on the equivalent temperature of the circle center, a self-correcting decoupling model is used to solve the test area model;

[0012] Based on the solving result, the temperature field of the test area is predicted.

[0013] Further, a virtual boundary is drawn based on the pipe diameter and a heat insulation condition is applied to establish a ring-based single pipe influence domain independent model, wherein:

[0014] The control equation and boundary condition of the ring-based single pipe influence domain independent model are:

[0015]

[0016] Wherein, n is the outer normal direction, Ω e represents the ring independent influence domain, x is the space coordinate, τ is the historical time process, θ represents the adiabatic temperature rise of concrete, K is the thermal conductivity, α represents the temperature conduction coefficient, T e represents the temperature field function of the influence domain, T w represents the water temperature of the water pipe, Δ represents the Laplace operator, Γ v represents the virtual boundary (outer circle boundary), Γ p represents the pipe wall (inner circle boundary), h p is the convective heat transfer coefficient of the pipe wall and water flow, is the partial derivative.

[0017] Further, the collocation number expression is:

[0018]

[0019] Wherein, r is the point position radius, r p is the pipe wall radius, n e is the number of points per meter, ceil represents the upward integer function.

[0020] Further, the local radial basis function collocation method is used to collocate points on the influence domain and construct a solving equation, wherein:

[0021] The equation is:

[0022]

[0023] where: a represents the thermal conductivity coefficient, Δ represents the Laplace operator, τ is the historical time process, T e n is the temperature value at the previous time, T e n+1 is the unknown temperature value at the next time, x is the spatial coordinate, Γ v represents the virtual boundary (outer circular boundary), Γ p represents the circular tube wall (inner circular boundary), K is the thermal conductivity coefficient, h p is the convective heat transfer coefficient of the tube wall and water flow, T w represents the water temperature, n is the outer normal direction, ΔT e n+1 or The weight function can be constructed by the local radial basis function collocation method, and the temperature value on the collocation point is given:

[0024]

[0025] where L i represents the linear transformation operator of the i-th collocation point, T e n+1 is the unknown temperature value at the next time, N represents the total number of points, T j represents the temperature value on the j-th collocation point, w ij is the weight function, j = 1, …, N;

[0026] The radial basis function is:

[0027]

[0028] where Φ(r) represents the radial basis function, c represents the shape parameter, r represents the distance between two test points, and the shape parameter is given by formula (S.6):

[0029]

[0030] where n s is the local collocation number, x i is the center of the sub-region constructed, represents the point in the sub-region, and s is a parameter related to the size of the region, which is given by formula (S.7):

[0031] s = 3d / 4, (S.7)

[0032] where d is the characteristic length of the calculation domain.

[0033] Further, based on the temperature field near the tube wall, an equivalent function and an equivalent parameter are introduced for calculation, to obtain the equivalent temperature of the circle center, where:

[0034] T(r) = f(a,b,r,m), (S.8)

[0035] where T(r) represents the temperature of the corresponding position radius, f is an equivalent function, m is an equivalent parameter, a and b are the correlation coefficients of the equivalent function, r is the point position radius, and m>0 by default, and if the value of m is given, a and b are solved by the following formula:

[0036]

[0037] where r1 is the radius value of the closest set of matching points to the pipe wall, r p is the pipe radius;

[0038] Through numerical tests, the equivalent function is defined as:

[0039] f(a,b,r,m)=a r m +b, (S.10)

[0040] We can get:

[0041] T(0)=b.(S.11)

[0042] where a represents the temperature gradient correlation coefficient, and b is the equivalent temperature.

[0043] Further, based on the equivalent temperature of the center of the circle, the test area model is solved by a self-correcting decoupling model, including:

[0044] The test area model is a square area, which is large enough to cover the influence domain described in step one, and contains a single pipe located at the center of the domain, satisfying the following control equation:

[0045]

[0046] where Ω t represents a square test domain, x is a spatial coordinate, τ is a historical time process, θ represents the adiabatic temperature rise of concrete, K is the thermal conductivity, α represents the temperature conduction coefficient, T w represents the water temperature of the water pipe, Γ p represents the circular pipe wall (inner circular boundary), h p is the convective heat transfer coefficient of the pipe wall and water flow, T t represents the temperature field function of the test domain, Γ b represents the square four surrounding boundaries, h b is the convective heat transfer coefficient of the concrete block and the surrounding environment, T b is the surrounding environment temperature.

[0047] Further, based on the equivalent temperature of the center of the circle, the test area model is solved by a self-correcting decoupling model, including:

[0048] The pipe wall temperature is obtained by using the influence domain;

[0049] Substitute the pipe wall temperature into the test area model in the form of the circle center equivalent temperature, and replace the distribution points on the circular pipe wall with the center point;

[0050] Obtain the virtual boundary (outer circle boundary) temperature of the influence domain by solving the temperature field of the test area;

[0051] Resolving the temperature field in the influence domain based on the pipe wall temperature and the virtual boundary (outer circle boundary) temperature, the calculation formula is:

[0052]

[0053] Wherein Indicates the obtained temperature value, T e Indicates the temperature field function of the influence domain, τ is the history time process, a indicates the thermal conductivity coefficient, Δ indicates the Laplace operator, θ indicates the adiabatic temperature rise of concrete, x is the spatial coordinate, Ω e Indicates the annular independent influence domain, and Γ indicates the physical area boundary.

[0054] Further, based on the solving result, the temperature field of the test area is predicted, including:

[0055] Compare the solving result with the original solution decoupling model solution and obtain the equivalent parameter m by using the dichotomy method;

[0056] Based on the new model containing the equivalent parameter m, the temperature field of the test area is predicted.

[0057] The second aspect is a concrete temperature field prediction device containing a pipeline, including a processor and a storage medium;

[0058] The storage medium is used for storing instructions;

[0059] The processor is used for operating according to the instructions to execute the steps of the method according to any one of the above.

[0060] The third aspect is a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps of the method according to any one of the above.

[0061] Compared with the prior art, the beneficial effects achieved by the present application are:

[0062] I, the present application can achieve the effect of saving data reconstruction time and computing cost, solve the existing technology containing multi water pipe concrete block temperature field calculation process involves the structure complex, there is a large size ratio, grid or point optimization difficulty, slow convergence problem, has the characteristics of simple mathematical model, low difficulty and small number of grid or point construction, high precision, high computing efficiency, is the effective method of different pipe diameter, large number of water pipes, high temperature gradient near the pipe wall and large size ratio structure heat transfer calculation, which meets the efficient and stable characteristics of the numerical simulation of the temperature field of the multi water pipe concrete block. The established pipe wall influence domain independent model realizes the accurate calculation of the pipe wall temperature, and the precision reaches 10 -3 ; the influence domain model and the whole model are combined in order by decoupling the model to reduce the size ratio of the structure and avoid the optimization process of grid division or point distribution; based on the numerical equivalent method, the pipe wall temperature value is equivalent to a point, which reduces the difficulty of point distribution and reduces the number of point distribution required by the large size ratio structure; the grid or point distribution is relatively fixed, and when the size ratio increases, the grid or point distribution does not need to be encrypted; the local radial basis function distribution method can be used to realize the fast and accurate prediction of the cross section temperature field of the concrete block containing multiple water pipes; the proposed model can adapt to the heat transfer simulation of the pipe radius of 5mm to 1dm, covering all pipe diameter ranges used for concrete cooling in engineering.

[0063] II, the decoupling new model based on equivalent temperature is proposed according to the characteristics of high temperature gradient near the pipe wall, which meets the requirements of fast and accurate calculation of the cross section heat transfer process of the multi water pipe; the established pipe wall influence domain independent model is an important tool for accurately solving the pipe wall temperature, which cooperates with the whole model in order to construct a decoupling model, which not only effectively reduces the size ratio between the water pipe structure and the concrete block in the original problem, but also avoids the process of grid redivision or re-optimized point distribution when the pipe diameter is adjusted, the number of pipes is increased or decreased, and the pipe position is changed; only fixed grid or point distribution can be used to conveniently realize the solution of complex pipe structure, which meets the requirements of simple and efficient mathematical model in the design process of three-dimensional complex pipe system; the numerical equivalent method of pipe wall temperature effectively equivalent the pipe wall temperature value to the center of the pipe, reduces the number of point distribution on the pipe wall, reduces the difficulty of point distribution, and only requires the point distribution on the whole model to meet the solution accuracy when there is no water pipe, which reduces the number of point distribution from the whole, and when the pipe diameter is small (or the size ratio is large), the equivalent method has obvious advantages and can significantly reduce the number of grid or point distribution. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 is the flow chart provided by the embodiment one of the present application;

[0065] Figure 2 is the pipe wall influence domain independent model schematic diagram provided by the embodiment one of the present application;

[0066] Figure 3is a flow chart for definition and calculation of equivalent parameters provided by embodiment one of the present application;

[0067] Figure 4 is a curve of equivalent temperature changing with equivalent parameters provided by embodiment one of the present application;

[0068] Figure 5 is a curve of temperature value and error changing with time for different pipe diameters provided by embodiment one of the present application;

[0069] Figure 6 is a temperature field schematic diagram provided by embodiment one of the present application;

[0070] Figure 7 is a relative deviation cloud chart provided by embodiment one of the present application. DETAILED DESCRIPTION

[0071] The present application will be further described below in conjunction with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0072] Embodiment one:

[0073] A concrete temperature field prediction method containing a pipeline, the specific steps are as follows:

[0074] Step one, according to the water pipe diameter, a virtual boundary is drawn and an adiabatic condition is applied, an annular single pipe influence domain independent model is established, and its control equation and boundary condition are given by formula (S.1):

[0075]

[0076] Wherein, n is the outer normal direction, Ω e represents the annular independent influence domain, x is the space coordinate, τ is the historical time process, θ represents the adiabatic temperature rise of concrete, K is the thermal conductivity, α represents the temperature conduction coefficient, T e represents the temperature field function of the influence domain, T w represents the water temperature of the water pipe, Δ represents the Laplace operator, Γ v represents the virtual boundary (outer circular boundary), Γ p represents the circular pipe wall (inner circular boundary), h p is the convective heat transfer coefficient of the pipe wall and water flow, is the partial derivative.

[0077] Step two, according to formula (S.1), using local radial basis function collocation method, collocation points are arranged on the influence domain and the solving equation is constructed, wherein:

[0078] The number of collocation points and the radius have the following relationship:

[0079]

[0080] where r is the point position radius, r p is the tube wall radius, n e is the number of points per meter, ceil denotes the upward rounding function. According to the above formula, only n e is given, the number of points N(r) at any radius position can be obtained to perform uniform point distribution;

[0081] Based on the above point distribution formula (S.1), using the local radial basis function point distribution method and the implicit difference format, the following equation is constructed to solve:

[0082]

[0083] where a represents the temperature coefficient, Δ represents the Laplace operator, τ is the historical time process, T e n is the temperature value at the previous time, T e n+1 is the unknown temperature value at the next time, x is the spatial coordinate, Γ v represents the virtual boundary (outer circular boundary), Γ p represents the circular tube wall (inner circular boundary), K is the thermal conductivity, h p is the convective heat transfer coefficient of the tube wall and water flow, T w represents the water temperature in the pipe, n is the outer normal derivative, ΔT e n+1 or The weight function can be constructed by the local radial basis function point distribution method, and the temperature value on all points is given:

[0084]

[0085] where L i is the linear transformation operator of the i-th point, T e n+1 is the unknown temperature value at the next time, N represents the total number of points, T j represents the temperature value on the j-th point, w ij is the weight function. N equations on N points of T j can be obtained by formula (S.3) and formula (S.4), and then T j , j = 1, …, N can be solved.

[0086] The radial basis function used to solve the heat transfer problem is a multiple quadratic surface radial basis function (MQ-RBF), and the formula is:

[0087]

[0088] where Φ(r) represents the radial basis function, c represents the shape parameter, r represents the distance between two test points, and the shape parameter is given by formula (S.6):

[0089]

[0090] where n s is the number of local points, x i is the center of the sub-region, represents the points in the sub-region, and s is a parameter related to the size of the region, given by equation (S.7):

[0091] s = 3d / 4, (S.7)

[0092] where d is the characteristic length of the calculation domain.

[0093] Step three, based on the temperature field near the pipe wall, an equivalent function and an equivalent parameter m are introduced to approximately obtain the center temperature equivalent to the pipe wall temperature, where:

[0094] The default equivalent temperature is less than the pipe wall temperature, and the introduced equivalent function is a numerical equivalent determined by the temperature values of the pipe wall and the pipe wall, which has the following form:

[0095] T(r) = f(a, b, r, m), (S.8)

[0096] where T(r) represents the temperature corresponding to the position radius, f is the equivalent function, m is the equivalent parameter, a and b are the related coefficients of the equivalent function, and r is the point position radius. By default, m > 0, and if the value of m is given, a and b are solved by the following equation:

[0097]

[0098] where r1 is the radius value of the nearest set of points to the pipe wall, r p is the pipe radius;

[0099] Through numerical tests, the equivalent function is defined as:

[0100] f(a, b, r, m) = a r m + b, (S.10)

[0101] We can get:

[0102] T(0) = b, (S.11)

[0103] where a represents the temperature gradient correlation coefficient, and b is the equivalent temperature.

[0104] When the equivalent temperature is greater than the pipe wall temperature, the temperature values at r1 and r p are swapped, and then b is solved; or m is made negative, and the equivalent temperature T e = b is still obtained.

[0105] Step four, establish a square test area model with a single water pipe, its control equation and boundary conditions are as follows, wherein:

[0106] The test area model is a square area, which is large enough to cover the influence domain described in step one, and the single pipe is located at the center of the domain, which satisfies the following control equation:

[0107]

[0108] Wherein, Ω t represents a square test domain, x is a spatial coordinate, τ is a historical time process, θ represents the adiabatic temperature rise of concrete, K is the thermal conductivity, α represents the temperature conduction coefficient, T w represents the water temperature of the water pipe, Γ p represents the wall of the circular pipe (inner circular boundary), h p is the convective heat transfer coefficient of the pipe wall and water flow, T t represents the temperature field function of the test domain, Γ b represents the square four side boundary, h b is the convective heat transfer coefficient of the concrete block and the surrounding environment, T b is the temperature of the surrounding environment, and n is the outer normal direction.

[0109] Step five, based on the self-correcting decoupling model and using the equivalent temperature of the center, the test area is solved, and the self-correcting decoupling model used has the following solving ideas:

[0110] 1) Use the influence domain model in step one to obtain the pipe wall temperature;

[0111] 2) Substitute the pipe wall temperature in the equivalent form in step three into the test area in step four, replace the points on the circular pipe wall with the center point, and simplify the points and the model;

[0112] 3) By solving the temperature field of the test area, the temperature value on the virtual (outer circular) boundary of the influence domain in step one is obtained;

[0113] 4) Substitute the pipe wall temperature and the virtual (outer circular) boundary temperature obtained in 1) and 3) into the following formula:

[0114]

[0115] Wherein represents the obtained temperature value, T e represents the temperature field function of the influence domain, τ is the historical time process, α represents the temperature conduction coefficient, Δ represents the Laplace operator, θ represents the adiabatic temperature rise of concrete, x is a spatial coordinate, Ω e represents a ring-shaped independent influence domain, Γ is the physical area boundary, and the temperature field in the influence domain is re-solved by the above formula, which is regarded as a first correction process:

[0116] 5) Finally, the accurate prediction of the test area (including the influence of the temperature field inside and outside the domain) is achieved.

[0117] Then, the results are compared with the original model solution and the equivalent parameter m is obtained by bisection method, and the solution process is shown in Figure 3 . Figure 4 is the curve of equivalent temperature with equivalent parameter m, which is piecewise monotonic. First, set the initial range of equivalent parameter m as [m1, m2], and then compare the calculation results of the average temperature of the influence domain boundary with the original model solution. The resulting deviation R needs to satisfy R(m1) x R(m2) < 0, and the bisection method is used to continuously reduce the range of m value until the absolute value of R(m) is less than a certain limit value such as 10 -3 , and finally the approximate value of m is obtained.

[0118] (6) The new model based on equivalent parameter m is applied to the simulation of the cross-section temperature field of concrete blocks containing multiple water pipes. The new model is applied to the simulation of the cross-section temperature field of concrete blocks containing multiple water pipes. The point density is consistent with the test area, and through step three, multiple water pipes can be regarded as multiple points at the corresponding center position, without the need for discrete point distribution on each pipe wall, greatly simplifying the point distribution process. At the same time, through the decoupling model in step five, the accurate simulation of the temperature value of any point in the region is ensured, and the temperature field of the concrete block containing multiple water pipes is efficiently and accurately predicted.

[0119] Square area calculation of single pipe with different pipe diameters, area side length L = 3m, pipe radius r p 0.01m, 0.02m, 0.04m, 0.08m, time step 0.02 days. The known conditions are as follows: bottom heat insulation, upper boundary air contact heat transfer coefficient h a = 5.62 W / (m 2 ℃), left and right boundary wood contact heat transfer coefficient h b = 7.82 W / (m 2 ℃), convective heat transfer coefficient h p = 40 W / (m 2 ℃), water temperature T w = 10℃, concrete initial temperature T0 = 30℃, air (environment) temperature T a = 15℃, concrete material density ρ = 2400 kg / m 3 , specific heat capacity C = 945 J / (kg℃), thermal conductivity K = 2.625 W / (m℃), adiabatic temperature rise caused by hydration heat

[0120] Figure 5(a)-(d) respectively give the comparison of the average temperature of pipe wall, virtual boundary, the maximum temperature of the region and the standard deviation (d) with the results of the original finite element model, and the change of the relative standard deviation (d) with time. From the comparison of the results of (a)-(c), it can be seen that when the pipe radius is from 0.01-0.08m, the calculation results of the decoupling model SCM and the original model FEM are almost the same; from the figure (d), it can be seen that the relative standard deviation is within 10 -2 The above results show that the SCM can accurately simulate the temperature field of the region containing a single water pipe.

[0121] The calculation of the region containing multiple water pipes considers two schemes of r p =0.04m and 6 pipes and r p =0.03m and 10 pipes, the side length of the square is 3m, and the time step is 0.02 days. The known conditions are the same as those of the single pipe condition.

[0122] Figure 6 and Figure 7 respectively give the simulation results and the relative deviation cloud map (τ=2 days) of the temperature field of the region. Figure 6 The temperature field contour shown is smooth, the calculation result is stable, and can reflect the high temperature gradient near the pipe wall. From Figure 7 It can be seen that by changing the number of pipes and the pipe diameter, the relative deviation of the results can be kept within 10 -2 The maximum deviation in the domain occurs on the virtual boundary, which is mainly caused by the uniform distribution of points in the square region, and can be further reduced by appropriately adjusting the points near the virtual boundary. The above results show that the proposed model can accurately predict the temperature field of the cross section of the concrete block containing multiple water pipes.

[0123] In summary, the decoupling model provided by the application can simplify the grid or point distribution by equivalent the pipe wall temperature to the center point temperature, and can be conveniently used to predict the temperature field of the region containing multiple water pipes. The application follows the cooling law and characteristics of the concrete water pipe, has the characteristics of high precision, fast calculation, simple program and strong expandability; can be applied to the heat transfer calculation of the concrete block cross section containing multiple pipe holes, large size ratio of cross section to pipe diameter and three-dimensional complex pipe system, and meets the characteristics of simple and efficient and stable mathematical model required for predicting the temperature field of the concrete block containing multiple water pipes.

[0124] The experimental comparison shows that the new model provided by the application can effectively analyze the temperature field change of the concrete block with 6 pipes, 10 pipes and other multiple pipes, and accurately describe the temperature field change near the pipe wall. Under the condition of obtaining similar accuracy, the more the number of pipes is, the more obvious the advantage of the model is. The decoupling process is clear and simple, and can realize fast and accurate simulation of the temperature field of the region with multiple pipes, and the precision is maintained at about 10-3; the established model can be used to simplify the curved pipe into a curve, which is convenient for solving and improves the stability of calculation; and can further expand the design of three-dimensional complex pipe system, including pipe diameter selection, pipe length, layout position, water flow control, water flow direction setting and the like.

[0125] The application provides a simple and efficient modeling tool for accurately predicting the temperature field of the concrete block with multiple pipes, and is a new model for designing the pipe cooling system of the concrete block, and can also be used for heat transfer calculation of similar complex pipe systems, such as the influence of geothermal energy and plants on the environment temperature.

[0126] Embodiment two:

[0127] The embodiment of the application further provides a concrete temperature field prediction device with pipes, including a processor and a storage medium.

[0128] The storage medium is used for storing instructions.

[0129] The processor is used for operating according to the instructions to execute the steps of the following method:

[0130] The pipe diameter of the water pipe is obtained.

[0131] Based on the pipe diameter of the water pipe, a virtual boundary is drawn and an adiabatic condition is applied, and an annular single-pipe influence domain independent model is established.

[0132] Based on the annular single-pipe influence domain independent model, a local radial basis function collocation method is used to collocate points on the influence domain and construct a solving equation to obtain the temperature field near the pipe wall.

[0133] Based on the temperature field near the pipe wall, an equivalent function and an equivalent parameter are introduced for calculation to obtain the equivalent temperature of the center.

[0134] Based on the equivalent temperature of the center, a self-correcting decoupling model is used to solve the test area model.

[0135] Based on the solving result, the temperature field of the test area is predicted.

[0136] Embodiment three:

[0137] The embodiment of the application further provides a computer readable storage medium, which stores a computer program, and the program is executed by the processor to realize the steps of the following method:

[0138] acquiring a pipe diameter of the water pipe;

[0139] drawing a virtual boundary based on the pipe diameter of the water pipe and applying an adiabatic condition to establish a ring-shaped single-pipe influence domain independent model;

[0140] based on the ring-shaped single-pipe influence domain independent model, using a local radial basis function collocation method to collocate points on the influence domain and constructing a solving equation to acquire a temperature field near the pipe wall;

[0141] based on the temperature field near the pipe wall, introducing an equivalent function and an equivalent parameter for calculation to obtain a center equivalent temperature;

[0142] based on the center equivalent temperature, solving a test area model by using a self-corrected decoupling model;

[0143] based on a solving result, predicting a temperature field of the test area.

[0144] Those skilled in the art will understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer usable program code.

[0145] 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 flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams 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 apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0146] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0147] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer-implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the flowchart Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks to perform the functions specified in the flowchart

[0148] The above description is only the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can also be made, these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method for predicting a temperature field of a pipe-embedded concrete, characterized by, The method comprises the following steps: acquiring the pipe diameter of the water pipe; drawing a virtual boundary based on the pipe diameter of the water pipe and applying an adiabatic condition to establish a ring-shaped single-pipe influence domain independent model; based on the ring-shaped single-pipe influence domain independent model, using a local radial basis function collocation method to collocate points on the influence domain and constructing a solving equation to acquire a temperature field near the pipe wall; based on the temperature field near the pipe wall, introducing an equivalent function and an equivalent parameter to perform calculation to obtain a circle center equivalent temperature; based on the circle center equivalent temperature, solving a test area model by using a self-corrected decoupling model; based on the solving result, predicting a temperature field of the test area; wherein the acquisition of the equivalent function comprises: T(r)=f(a,b,r,m),(S.8) wherein T(r) represents a temperature of a corresponding position radius, f is an equivalent function, m is an equivalent parameter, a and b are relevant coefficients of the equivalent function, r is a point position radius, and m>0, if a given m value is given, a and b are solved by the following formula: where r1 is the radius value of the set of points closest to the pipe wall, r p is the pipe radius; through numerical tests, the equivalent function is defined as: f(a, b, r, m) = a r m + b, (S.10) the acquisition of the equivalent parameter comprises: comparing the solving result of the test area model with an original decoupling model solution and using a dichotomy method to acquire the equivalent parameter m; the test area model is a square area, the size of which is sufficient to cover the influence domain, and a single pipe is located at the center of the domain, satisfying the following control equation: where Ω t represents a square test domain, x is a spatial coordinate, τ is a history time progression, θ represents the adiabatic temperature rise of concrete, K is a thermal conductivity, a represents a temperature conduction coefficient, T w represents a water pipe water temperature, Γ p represents a circular pipe wall, h p is a pipe wall and water flow convection heat transfer coefficient, T t represents a test domain temperature field function, Γ b represents a square four perimeter boundary, h b is a concrete block and surrounding environment convection heat transfer coefficient, T b is a surrounding environment temperature, n is an external normal direction, Δ represents a Laplace operator, is a partial derivative.

2. The concrete temperature field prediction method with pipes according to claim 1, characterized in that, a virtual boundary is drawn based on the pipe diameter of the water pipe and an adiabatic condition is applied to establish a ring-shaped single-pipe influence domain independent model, wherein: the control equation and the boundary condition of the ring-shaped single-pipe influence domain independent model are: where n is the outward normal direction, Ω e denotes the circular independent influence domain, x is the spatial coordinate, τ is the history time process, θ represents the adiabatic temperature rise of concrete, K is the thermal conductivity, α represents the temperature conduction coefficient, T e denotes the temperature field function of the influence domain, T w denotes the water pipe water temperature, Δ denotes the Laplace operator, Γ v denotes the virtual boundary, Γ p denotes the circular pipe wall, h p is the convective heat transfer coefficient of the pipe wall and water flow, is the partial derivative.

3. The duct-inclusion concrete temperature field prediction method according to claim 2, characterized by, the collocation number expression is: where r is the point position radius, r p is the tube wall radius, n e is the number of points per meter, and ceil denotes the ceiling function.

4. The concrete temperature field prediction method with pipes according to claim 1, characterized in that, a local radial basis function collocation method is used to collocate points on the influence domain and construct a solving equation, wherein: the equation is: where: α represents the temperature coefficient, Δ represents the Laplace operator, τ is the historical time process, θ represents the adiabatic temperature rise of concrete, T e n is the temperature value at the previous time, T e n+1 is the unknown temperature value at the next time, x is the spatial coordinate, Ω e represents the annular independent influence domain, is the partial derivative, Γ v represents the virtual boundary, Γ p represents the circular pipe wall, K is the thermal conductivity, h p is the convective heat transfer coefficient of the pipe wall and water flow, T w represents the water temperature, n is the outer normal direction, ΔT e n+1 or The weight function can be constructed by the local radial basis function collocation method, and the temperature value on the collocation point is given: where L i represents the linear transformation operator of the i-th collocation point, T e n+1 is the unknown temperature value at the next time, N represents the total number of points, T j represents the temperature value at the j-th collocation point, w ij is the weight function, j = 1,..., N; the radial basis function is: wherein Φ(r) represents a radial basis function, c represents a shape parameter, and r represents a distance between two test points, and the shape parameter is given by formula (S.6): where n s is the number of local points, x i is the center of the sub-region, denotes a point within the sub-region, and s is a parameter related to the size of the region, given by equation (S.7): s=3d / 4, (S.7) wherein d is a characteristic length of the calculation domain.

5. The concrete temperature field prediction method with pipes according to claim 1, characterized in that, based on the temperature field near the pipe wall, an equivalent function and an equivalent parameter are introduced to perform calculation to obtain a circle center equivalent temperature T(0)=b.

6. The concrete temperature field prediction method with pipes according to claim 1, characterized in that, based on the circle center equivalent temperature, a test area model is solved by using a self-corrected decoupling model, comprising: the pipe wall temperature is solved by using the influence domain; the pipe wall temperature is substituted into the test area model in the form of the circle center equivalent temperature, and the center point is used to replace the collocation points on the circular pipe wall; by solving the temperature field of the test area, a virtual boundary temperature of the influence domain is obtained; based on the pipe wall temperature and the virtual boundary temperature, the temperature field in the influence domain is re-solved, and the calculation formula is: wherein denotes the obtained temperature value, T e denotes the temperature field function of the influence domain, τ is the history time progress, a denotes the thermal diffusivity, Δ denotes the Laplace operator, θ denotes the adiabatic temperature rise of the concrete, x is the spatial coordinate, Ω e denotes the annular independent influence domain, Γ denotes the physical region boundary, is the partial derivative.

7. The concrete temperature field prediction method with pipes according to claim 1, characterized in that, based on the solving result, a temperature field of the test area is predicted, comprising: based on a new model containing the equivalent parameter m, a temperature field of the test area is predicted.

8. A device for predicting a temperature field of a concrete containing a pipe, characterized by comprising a processor and a storage medium; the storage medium is for storing instructions; the processor is configured to operate in accordance with the instructions to perform the steps of the method of any one of claims 1-7.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, the program, when executed by the processor, implements the steps of the method of any one of claims 1-7.

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