Method for acquiring hydraulic data of pipe network single-phase fluid of pipe network system lacking measuring points

Abstract

The invention relates to a method for acquiring hydraulic data of a pipe network single-phase fluid of a pipe network system lacking measuring points, which combines the Kirchhoff's law with a fluid momentum conservation formula, and converts unknown variables such as an unknown resistance coefficient and a manual valve in a fluid network into a relationship between pressure and flow through parameter transformation. And the coupling relational expression of the pressure and the flow is substituted into the fluid network iteration process for common iteration, and finally the pressure distribution condition of the whole fluid network system can be calculated according to the flow of the inlet and the outlet. The method is based on a fluid network theory, a pipe network single-phase fluid hydraulic calculation algorithm is used for solving the problem of hydraulic simulation calculation of a pipeline system according to the situation that the real pipe network system is lack of measuring points, and the precision and the coverage degree of pipeline monitoring are improved.

Description

Technical Field

[0001] The invention relates to a method for acquiring hydraulic data of a single-phase fluid in a pipe network system lacking measuring points, and belongs to the technical field of fluid network hydraulics. Background Art

[0002] In actual production and life, pipeline transportation is the most common, widespread and economical mode of transportation. However, in the process of fluid transportation, due to the complexity of the pipeline network, the lack of effective measurement points, and the lack of effective monitoring methods for the fluid inside the pipeline with rapid hydraulic and thermal changes.

[0003] In the field of theoretical research and in precision pipeline systems, the principle of fluid network calculation can accurately calculate pipeline hydraulic data. However, in the actual production process, the internal resistance coefficient of the pipeline and the valve opening and related data of the manual regulating valve are usually unknown, making it difficult to calculate using conventional fluid network theory.

[0004] In recent years, the application of fluid network theory has been continuously expanded and deepened. However, hydraulic calculations for pipeline systems with scarce or rapidly changing hydraulic data measurement points are often unable to be achieved with the help of theoretical calculations. Therefore, there is an urgent need for a method to obtain hydraulic data of fluid networks without measurement points in internal pipeline systems. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses a method for acquiring hydraulic data of a single-phase fluid in a pipe network system lacking measuring points, and the specific technical solution is as follows: A method for acquiring hydraulic data of a single-phase fluid in a pipe network system lacking measuring points comprises the following steps: Step S1, data input and initialization: input the fluid network topology matrix and the original boundary data of the fluid network, and initialize the input data; Step S2, setting the iteration step and solving the pressure matrix: after setting the iteration step, entering the iteration loop, solving the data obtained in step S1 according to the mass conservation formula and the momentum conservation formula, constructing the pressure matrix equation, and solving the pressure matrix using the LU decomposition method; Step S3, solving a new internal flow matrix: Substituting the solution data of the pressure matrix obtained in step S2 and the data of step S1 into the streamline momentum equation for solving, and obtaining a new internal flow matrix; Step S4, updating the internal node density array: according to the internal flow matrix obtained in step S3, combined with the data in step S1, substitute into the mass conservation formula to solve, and then obtain the updated internal node density array; Step S5, solving the updated internal node specific enthalpy array: Substitute the internal node density array obtained in step S4 and the data obtained in step S1 into the energy conservation formula, construct the specific enthalpy matrix equation, and then use the LU decomposition method to solve the specific enthalpy matrix equation to obtain the updated internal node specific enthalpy array; Step S6, adjusting the internal flow matrix: adding the internal flow matrix obtained after iteration in step S3 to the initial internal flow matrix in step S1 and calculating the average value to obtain a new internal flow matrix; Step S7, updating the node pressure array: updating the pressure item by item according to Kirchhoff's law and Darcy-Weisbach formula; Step S8, updating the density array and the resistance matrix: updating to obtain a new internal resistance matrix and a boundary resistance matrix; Step S9, determine whether the iteration is finished: determine whether the pressure converges, if it converges, it is finished, if not, return to step S2.

[0006] Furthermore, in step S1, the original boundary data of the fluid network includes node temperature data, boundary node flow or pressure data, internal node pipe length and diameter data, and inlet pressure; The specific steps for initializing the input data are as follows: based on the fluid network topology matrix, the node data to be determined and the overall data are vectorized, and the streamline data is matrixed; with the help of the IAPWS water vapor library, other initial data are calculated and solved through the initial pressure and temperature; finally, 10 sets of vector data are obtained, namely, the internal node temperature array, the boundary node temperature array, the internal node pressure array, the boundary node pressure array, the internal node specific enthalpy array, the boundary node specific enthalpy array, the internal node pipe length array, the internal node pipe diameter array, the internal node density array, and the boundary node density array; 5 sets of matrix data, namely, the internal flow matrix, the boundary flow matrix, the internal resistance matrix, the boundary resistance matrix, and the fluid network topology matrix; and 1 numerical data, namely, the inlet pressure value.

[0007] Furthermore, in step S1, the pipe network to be calculated is modeled according to the fluid network theory to obtain the fluid network topology matrix; the specific process is: a section of the pipe is regarded as an internal node, and the position where the pipe system boundary is connected to the outside of the system is set as the boundary node. The boundary node has temperature and pressure data, but no entity, so there is no pipe length and diameter data. The nodes are connected by streamlines, and the streamlines represent the fluid flow relationship between the pipes, thereby obtaining the fluid network topology matrix. The fluid network matrix includes the internal topology matrix and the boundary topology matrix, which are combined and called the fluid network topology matrix in actual use; the size of the internal topology matrix is ​​n×n, where n is the number of internal nodes; the size of the boundary topology matrix is ​​n×m, where n is the number of internal nodes and m is the number of boundary nodes; the internal node topology relationship matrix There are three values ​​of : 0 means that there is no streamline connection between node i and node j; -1 means that the streamline direction is from i to j; 1 means that the streamline direction is from j to i; the array constructed in step S1, the array size associated with the internal nodes is n, and the array size associated with the boundary nodes is m; the matrix constructed in step S1, the matrix size associated with the internal is n×n, and the matrix size associated with the boundary is n×m.

[0008] Furthermore, in step S2, the five sets of data obtained in step S1, namely, the internal node pressure array, the boundary node pressure array, the fluid network topology matrix, the internal flow matrix and the boundary flow matrix, are solved simultaneously according to the mass conservation formula and the momentum conservation formula to construct a pressure matrix equation, and the pressure matrix is ​​solved by the LU decomposition method to obtain an updated internal node pressure array. The specific process is as follows: The formula for conservation of mass is: , Where V is the node volume, is the node density, t is the time, Internal node topology relationship matrix, is the boundary topological relationship matrix, is the internal traffic matrix, is the boundary traffic matrix, n is the number of internal nodes, m is the number of external nodes, i, j, k are all node numbers, subscript ij represents the relationship between internal node i and internal node j, and subscript ik represents the relationship between internal node i and boundary node k; The formula for conservation of momentum is: , Where I is the structural parameter, is the internal traffic matrix, is the internal topological matrix, P represents the node pressure, H is the power source term, and f is the streamline resistance term. When calculating, the flow process is assumed to be stable, and the flow rate will not fluctuate, that is, the flow process is steady, then I is 0, and the mass conservation formula and momentum conservation formula are jointly expanded to obtain the pressure matrix equation: , Among them, R represents the Darcy drag coefficient of the internal node, RE represents the Darcy drag coefficient of the boundary node, G is the internal flow matrix, GE is the boundary flow matrix, P is the internal node pressure, PE is the boundary node pressure, and t+1 is the next iteration time of t.

[0009] Furthermore, in step S3, the internal node pressure array obtained in step S2, and the four sets of data, namely, the internal resistance matrix, the boundary resistance matrix, and the fluid network topology matrix in step S1, are substituted into the streamline momentum equation for solving, thereby obtaining a new internal flow matrix; In step S4, the internal flow matrix obtained in step S3 is combined with the internal node length array, internal node diameter array, internal node density array and boundary flow matrix obtained in step S1, and is substituted into the mass conservation formula to solve, thereby obtaining an updated internal node density array.

[0010] Furthermore, in step S5, the internal node density array obtained in step S4, the internal node pipe length array, the internal node pipe diameter array, the internal flow matrix, and the boundary flow matrix obtained in step S1 are substituted into the energy conservation formula, and the energy conservation formula is: , Where V is the node volume, is the node density, is the internal topology matrix, is the boundary topology matrix, is the internal traffic matrix, is the boundary flow matrix, h is the internal node specific enthalpy, is the boundary node specific enthalpy, and S is the source term.

[0011] Furthermore, the step S7 is specifically as follows: Determine the flow direction of the node according to the fluid network topology matrix in step S1, use the inlet pressure value in step S1 as the starting point of the pipeline network, use the internal flow matrix obtained in step S6, and the internal resistance matrix and boundary resistance matrix in step S1 to substitute into the Darcy-Weisbach formula, solve the pressure difference between the nodes, and then apply Kirchhoff's law, starting from the starting point of the fluid network, update the pressure value of the node one by one according to the flow direction of the streamline between the nodes, and finally obtain a new internal node pressure array and a boundary node pressure array; The Darcy-Weisbach formula is: , in, is the head loss along the way, f is the friction coefficient, L is the pipe length, D is the pipe diameter, v is the average flow velocity of the fluid, and g is the acceleration due to gravity.

[0012] Furthermore, the step S8 is specifically as follows: According to the internal node pressure array and boundary node pressure array obtained in step S7, the internal node specific enthalpy array obtained in step S5, the internal node tube length array and the internal node tube diameter array obtained in step S1, and the fluid network topology matrix, numerical calculations are performed with the help of the IAPWS water vapor database, and the structure is constructed using the fluid network topology matrix to obtain a new internal node density array. At the same time, the node resistance coefficient is recalculated according to the Darcy-Weisbach formula to obtain a new internal resistance matrix and boundary resistance matrix.

[0013] Furthermore, the step S9 is specifically as follows: By calculating the residual absolute value array between the initial internal node pressure array entering step S2 and the internal node pressure array updated in step S7, if each item of the residual array is less than the set value, the loop is terminated; otherwise, the internal node pressure array and boundary node pressure array in step S7, the internal node specific enthalpy array obtained in step S5, the internal node density array, internal resistance matrix and boundary resistance matrix in step S8, the internal node temperature array, boundary node temperature array, internal node pipe length array, internal node pipe diameter array, boundary node specific enthalpy array, fluid network topology matrix, and inlet pressure value in step S1 are used as initial values, and the calculation is returned to step S2 to continue.

[0014] The beneficial effects of the present invention are: Theoretical basis innovation of the invention: This algorithm is based on fluid network theory, breaks through the calculation limitations of traditional algorithms, and provides a new idea and method for fluid hydraulic data processing in complex pipeline systems.

[0015] The data adaptability of the present invention is enhanced: the algorithm can effectively simulate and predict the fluid hydraulic data of the pipeline system even when there are few measuring points, the internal resistance coefficient of the pipeline is unknown, and the pipeline valve opening data and valve relationship cannot be obtained, thereby greatly expanding the scope of application of the algorithm.

[0016] The present invention has improved predictive capabilities: In the face of the above-mentioned difficulties of missing data and uncertainty, the present invention demonstrates excellent simulation and predictive capabilities, significantly improving the accuracy and reliability of fluid hydraulic data prediction, and providing strong support for related decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the present invention, Figure 2 It is a schematic diagram of an example pipeline of the present invention being divided into four nodes and having two boundary nodes. Figure 3 It is a basic topological structure diagram of a pipeline network according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0019] Combined with Figure 1 It can be seen that the specific process of the present invention is: S1 Data input and initialization: Input the fluid network topology matrix and the original boundary data of the fluid network, which include node temperature data, boundary node flow or pressure data, internal node pipe length and diameter data, and inlet pressure. Initialize the input data: According to the fluid network topology matrix, the node data to be calculated and the overall data are vectorized, and the streamline data is matrixed. With the help of the IAPWS water vapor library, other initial data are calculated and solved by initial pressure and temperature. Finally, 10 sets of vector data are obtained, namely, internal node temperature array, boundary node temperature array, internal node pressure array, boundary node pressure array, internal node specific enthalpy array, boundary node specific enthalpy array, internal node pipe length array, internal node pipe diameter array, internal node density array, boundary node density array; 5 sets of matrix data, namely, internal flow matrix, boundary flow matrix, internal resistance matrix, boundary resistance matrix, fluid network topology matrix; and 1 numerical data, namely, the inlet pressure value.

[0020] The pipe network that needs to be calculated is modeled according to the fluid network theory. According to the pipe network installation drawings and calculation requirements, a section of pipe is regarded as an internal node, and the location where the pipe system boundary is connected to the outside of the system is set as a boundary node. The boundary node has data such as temperature and pressure, but there is no entity, so there is no pipe length and diameter data. The nodes are connected by streamlines, and the streamlines represent the fluid flow relationship between the pipes, thereby obtaining the fluid network topology matrix. The fluid network matrix contains the internal topology matrix and the boundary topology matrix, which are usually combined and called the fluid network topology matrix in actual use. The size of the internal topology matrix is ​​n×n, where n is the number of internal nodes; the size of the boundary topology matrix is ​​n×m, where n is the number of internal nodes and m is the number of boundary nodes. In the topology matrix, There are three values ​​for : 0 means there is no streamline connection between node i and node j; -1 means the streamline direction is from i to j; 1 means the streamline direction is from j to i. The array size of the array constructed in S1 related to the internal nodes is n, and the array size related to the boundary nodes is m; the matrix constructed in S1 has a matrix size of n×n related to the internal nodes, and a matrix size of n×m related to the boundary nodes.

[0021] like Figure 2 As shown, the pipeline is divided into four nodes and there are two boundary nodes.

[0022] The internal topology matrix is , The boundary topology matrix is .

[0023] S2 sets the iteration step and solves the pressure matrix: After setting the iteration step, enter the iteration loop, and solve the five sets of data obtained in S1, namely the internal node pressure array, boundary node pressure array, fluid network topology matrix, internal flow matrix and boundary flow matrix, according to the mass conservation formula and momentum conservation formula, to construct the pressure matrix equation, and use the LU decomposition method to solve the pressure matrix, so as to obtain the updated internal node pressure array.

[0024] The mass conservation formula is: , Where V is the node volume, is the node density, t is the time, is the internal node topological relationship matrix, is the boundary topological relationship matrix, is the internal traffic matrix, is the boundary flow matrix, n is the number of internal nodes, and m is the number of external nodes; The formula for conservation of momentum is: , Where I is the structural parameter, is the internal traffic matrix, is the internal topological matrix, P represents the node pressure, H is the power source term, and f is the streamline resistance term. When calculating, the flow process is assumed to be stable, and the flow rate will not fluctuate, that is, the flow process is steady, then I is 0, and the mass conservation formula and momentum conservation formula are jointly expanded to obtain the pressure matrix equation: , Among them, R represents the Darcy drag coefficient of the internal node, RE represents the Darcy drag coefficient of the boundary node, G is the internal flow matrix, GE is the boundary flow matrix, P is the internal node pressure, PE is the boundary node pressure, and t+1 is the next iteration time of t.

[0025] S3 solves the new internal flow matrix: Substitute the internal node pressure array obtained in S2 and the four sets of data, namely the internal resistance matrix, boundary resistance matrix and fluid network topology matrix in S1, into the streamline momentum equation for solution to obtain a new internal flow matrix.

[0026] S4 updates the internal node density array: based on the internal flow matrix obtained in S3, combined with the internal node pipe length array, internal node pipe diameter array, internal node density array and boundary flow matrix obtained in S1, substitute into the mass conservation formula to solve, and then obtain the updated internal node density array.

[0027] S5 solves the updated internal node specific enthalpy array: Substitute the internal node density array obtained in S4, the internal node pipe length array, the internal node pipe diameter array, the internal flow matrix, and the boundary flow matrix obtained in S1 into the energy conservation formula to construct the specific enthalpy matrix equation, and then use the LU decomposition method to solve the specific enthalpy matrix equation to obtain the updated internal node specific enthalpy array.

[0028] The energy conservation formula is: , Where V is the node volume, is the node density, is the internal node topological relationship matrix, is the boundary topological relationship matrix, is the internal traffic matrix, is the boundary flow matrix, h is the internal node specific enthalpy, is the boundary node specific enthalpy, and S is the source term.

[0029] S6 adjusts the internal flow matrix: add the internal flow matrix obtained after iteration in S3 and the initial internal flow matrix in S1 and calculate the average value to obtain a new internal flow matrix. This step is intended to slow down the convergence speed and prevent data distortion caused by too fast convergence.

[0030] S7 updates the node pressure array: determine the flow direction of the node according to the fluid network topology matrix in S1, use the inlet pressure value in S1 as the starting point of the pipeline network, use the internal flow matrix obtained in S6, and the internal resistance matrix and boundary resistance matrix in S1 to substitute into the Darcy-Weisbach formula to solve the pressure difference between the nodes. Then apply Kirchhoff's law, starting from the starting point of the fluid network, update the pressure value of the node one by one according to the flow direction of the streamline between the nodes, and finally obtain a new internal node pressure array and boundary node pressure array. Kirchhoff's law means that at the node of the fluid network, it is understood that the sum of the fluid flow into the node is equal to the sum of the fluid flow out of the node.

[0031] The Darcy-Weisbach formula is: , in, is the head loss along the way, f is the friction coefficient, L is the pipe length, D is the pipe diameter, v is the average flow velocity of the fluid, and g is the acceleration due to gravity.

[0032] S8 updates the density array and resistance matrix: Based on the internal node pressure array and boundary node pressure array obtained in S7, the internal node specific enthalpy array obtained in S5, the internal node pipe length array and internal node pipe diameter array obtained in S1, and the fluid network topology matrix, numerical calculations are performed with the help of the IAPWS water vapor database, and the fluid network topology matrix is ​​used for structural construction to obtain a new internal node density array. At the same time, the node resistance coefficient is recalculated according to the Darcy-Weisbach formula to obtain a new internal resistance matrix and boundary resistance matrix.

[0033] S9 determines whether the iteration is finished: by calculating the residual absolute value array between the initial internal node pressure array entering S2 and the updated internal node pressure array in S7, if each item of the residual array is less than the set value, the loop ends; otherwise, the internal node pressure array and boundary node pressure array in S7, the internal node specific enthalpy array obtained in S5, the internal node density array, internal resistance matrix and boundary resistance matrix in S8, the internal node temperature array, boundary node temperature array, internal node pipe length array, internal node pipe diameter array, boundary node specific enthalpy array, fluid network topology matrix, and inlet pressure value in S1 are used as initial values, and the calculation is returned to S2 to continue.

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is fully and clearly described below in conjunction with the logic diagram of the present invention: Model the pipe network system to be calculated, obtain the fluid network relationship topology matrix, input this matrix and other physical quantities (temperature, flow matrix and inlet pressure) into the algorithm program for initialization, and return the pressure distribution matrix after iterative calculation.

[0035] This algorithm has higher accuracy and stability when dealing with problems such as few measuring points and missing data, and can provide more effective support for the design, operation and maintenance of pipeline systems.

[0036] Figure 3 It is the basic topological structure diagram of the pipeline network. Figure 3 The numbers in are the point numbers, i.e. the measuring points. There are no measuring points in the middle of the pipeline network. The following table compares the simulated values ​​and measured values ​​of each measuring point at three groups of time: Table 1

[0037] It can be seen from the deviation data in the above table that, when the present invention is applied specifically, the deviation is within the allowable range and has industrial application value.

[0038] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for acquiring hydraulic data of a single-phase fluid in a pipe network system lacking measuring points, characterized in that: The following steps are involved: Step S1, data input and initialization: input the fluid network topology matrix and the original boundary data of the fluid network, and initialize the input data; Step S2, setting the iteration step and solving the pressure matrix: after setting the iteration step, entering the iteration loop, solving the data obtained in step S1 according to the mass conservation formula and the momentum conservation formula, constructing the pressure matrix equation, and solving the pressure matrix using the LU decomposition method; Step S3, solving a new internal flow matrix: Substituting the solution data of the pressure matrix obtained in step S2 and the data in step S1 into the streamline momentum equation for solving, and obtaining a new internal flow matrix; Step S4, updating the internal node density array: according to the internal flow matrix obtained in step S3, combined with the data in step S1, substitute into the mass conservation formula to solve, and then obtain the updated internal node density array; Step S5, solving the updated internal node specific enthalpy array: Substitute the internal node density array obtained in step S4 and the data obtained in step S1 into the energy conservation formula, construct the specific enthalpy matrix equation, and then use the LU decomposition method to solve the specific enthalpy matrix equation to obtain the updated internal node specific enthalpy array; Step S6, adjusting the internal flow matrix: adding the internal flow matrix obtained after iteration in step S3 to the initial internal flow matrix in step S1 and calculating the average value to obtain a new internal flow matrix; Step S7, updating the node pressure array: updating the pressure item by item according to Kirchhoff's law and Darcy-Weisbach formula; Step S8, updating the density array and the resistance matrix: updating to obtain a new internal resistance matrix and a boundary resistance matrix; Step S9, determine whether the iteration is finished: determine whether the pressure converges, if it converges, it is finished, if not, return to step S2.

2. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 1, characterized in that: In step S1, the original boundary data of the fluid network includes node temperature data, boundary node flow or pressure data, internal node pipe length and diameter data, and inlet pressure; The specific steps for initializing the input data are as follows: based on the fluid network topology matrix, the node data to be determined and the overall data are vectorized, and the streamline data is matrixed; with the help of the IAPWS water vapor library, other initial data are calculated and solved through the initial pressure and temperature; finally, 10 sets of vector data are obtained, namely, the internal node temperature array, the boundary node temperature array, the internal node pressure array, the boundary node pressure array, the internal node specific enthalpy array, the boundary node specific enthalpy array, the internal node pipe length array, the internal node pipe diameter array, the internal node density array, and the boundary node density array; 5 sets of matrix data, namely, the internal flow matrix, the boundary flow matrix, the internal resistance matrix, the boundary resistance matrix, and the fluid network topology matrix; and 1 numerical data, namely, the inlet pressure value.

3. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 2, characterized in that: In the step S1, the pipe network to be calculated is modeled according to the fluid network theory to obtain the fluid network topology matrix; the specific process is: a section of the pipe is regarded as an internal node, and the position where the pipe system boundary is connected to the outside of the system is set as a boundary node. The boundary node has temperature and pressure data, but no entity, so there is no pipe length and diameter data. The nodes are connected by streamlines, and the streamlines represent the fluid flow relationship between the pipes, thereby obtaining the fluid network topology matrix. The fluid network matrix includes the internal topology matrix and the boundary topology matrix, which are combined and called the fluid network topology matrix in actual use; the size of the internal topology matrix is ​​n×n, where n is the number of internal nodes; the size of the boundary topology matrix is ​​n×m, where m is the number of boundary nodes; in the fluid network topology matrix, the internal node topology relationship matrix There are three values ​​of : 0 means that there is no streamline connection between node i and node j; -1 means that the streamline direction is from i to j; 1 means that the streamline direction is from j to i; the array constructed in step S1, the array size associated with the internal nodes is n, and the array size associated with the boundary nodes is m; the matrix constructed in step S1, the matrix size associated with the internal is n×n, and the matrix size associated with the boundary is n×m.

4. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 1, characterized in that: In step S2, the five data sets of internal node pressure array, boundary node pressure array, fluid network topology matrix, internal flow matrix and boundary flow matrix obtained in step S1 are solved simultaneously according to the mass conservation formula and the momentum conservation formula to construct a pressure matrix equation, and the pressure matrix is ​​solved by LU decomposition method to obtain an updated internal node pressure array. The specific process is as follows: The mass conservation formula is: , Where V is the node volume, is the node density, t is the time, Internal node topology relationship matrix, is the boundary topological relationship matrix, is the internal traffic matrix, is the boundary traffic matrix, n is the number of internal nodes, m is the number of external nodes, i, j, k are all node numbers, subscript ij represents the relationship between internal node i and internal node j, and subscript ik represents the relationship between internal node i and boundary node k; The formula for conservation of momentum is: ， Where I is the structural parameter, is the internal traffic matrix, is the internal topological matrix, P represents the node pressure, H is the power source term, and f is the streamline resistance term. When calculating, the flow process is assumed to be stable and the flow rate will not fluctuate, that is, the flow process is steady, then I is 0, and the mass conservation formula and momentum conservation formula are jointly expanded to obtain the pressure matrix equation: ， Among them, R represents the Darcy drag coefficient of the internal node, RE represents the Darcy drag coefficient of the boundary node, G is the internal flow matrix, GE is the boundary flow matrix, P is the internal node pressure, PE is the boundary node pressure, and t+1 is the next iteration time of t.

5. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 3, characterized in that: In step S3, the internal node pressure array obtained in step S2 and the four sets of data, namely, the internal resistance matrix, the boundary resistance matrix and the fluid network topology matrix in step S1, are substituted into the streamline momentum equation for solving to obtain a new internal flow matrix; In step S4, the internal flow matrix obtained in step S3 is combined with the internal node length array, internal node diameter array, internal node density array and boundary flow matrix obtained in step S1, and is substituted into the mass conservation formula to solve, thereby obtaining an updated internal node density array.

6. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 3, characterized in that: In step S5, the internal node density array obtained in step S4, the internal node pipe length array, the internal node pipe diameter array, the internal flow matrix, and the boundary flow matrix obtained in step S1 are substituted into the energy conservation formula. The energy conservation formula is: ， Where V is the node volume, is the node density, is the internal topology matrix, is the boundary topology matrix, is the internal traffic matrix, is the boundary flow matrix, h is the internal node specific enthalpy, is the boundary node specific enthalpy, and S is the source term.

7. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 3, characterized in that: The step S7 is specifically as follows: Determine the flow direction of the node according to the fluid network topology matrix in step S1, use the inlet pressure value in step S1 as the starting point of the pipeline network, use the internal flow matrix obtained in step S6, and the internal resistance matrix and boundary resistance matrix in step S1 to substitute into the Darcy-Weisbach formula, solve the pressure difference between the nodes, and then apply Kirchhoff's law, starting from the starting point of the fluid network, update the pressure value of the node one by one according to the flow direction of the streamline between the nodes, and finally obtain a new internal node pressure array and a boundary node pressure array; The Darcy-Weisbach formula is: ， in, is the head loss along the way, f is the friction coefficient, L is the pipe length, D is the pipe diameter, v is the average flow velocity of the fluid, and g is the acceleration due to gravity.

8. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 3, characterized in that: The step S8 is specifically as follows: According to the internal node pressure array and boundary node pressure array obtained in step S7, the internal node specific enthalpy array obtained in step S5, the internal node tube length array and the internal node tube diameter array obtained in step S1, and the fluid network topology matrix, numerical calculations are performed with the help of the IAPWS water vapor database, and the structure is constructed using the fluid network topology matrix to obtain a new internal node density array. At the same time, the node resistance coefficient is recalculated according to the Darcy-Weisbach formula to obtain a new internal resistance matrix and boundary resistance matrix.

9. The method for acquiring hydraulic data of single-phase fluid in a pipe network system lacking measuring points according to claim 1, characterized in that: The step S9 is specifically as follows: By calculating the residual absolute value array between the initial internal node pressure array entering step S2 and the internal node pressure array updated in step S7, if each item of the residual array is less than the set value, the loop is terminated; otherwise, the internal node pressure array and boundary node pressure array in step S7, the internal node specific enthalpy array obtained in step S5, the internal node density array, internal resistance matrix and boundary resistance matrix in step S8, the internal node temperature array, boundary node temperature array, internal node pipe length array, internal node pipe diameter array, boundary node specific enthalpy array, fluid network topology matrix, and inlet pressure value in step S1 are used as initial values, and the calculation is returned to step S2 to continue.

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