A three-dimensional model method for calculating groundwater fissure flow, device and storage medium thereof

Abstract

The present invention relates to the technical field of water resource accounting, and in particular to a three-dimensional model method for calculating groundwater fissure flow, a device thereof, and a storage medium thereof. The method comprises: step one: constructing a three-dimensional fissure network and inputting variables of the network; step two: setting node water head values ​​and fissure flow values ​​of the network, and inputting the node water head values ​​and fissure flow values ​​into a program to obtain a Reynolds number value; step three: substituting the Reynolds number value into an equation to calculate a new node water head and fissure flow; step four: performing iterative calculation using the Newton-Raphson iteration method to respectively obtain the difference between the node water head and the fissure flow; step five: if the difference between the node water head and the fissure flow is less than 10 ‑5 , then output the final node head and fracture flow value; Step 6: If the difference between the node head and fracture flow is greater than or equal to 10 ‑5 , then proceed to step 2. Through the above method, the present invention improves the accuracy and speed of water resource accounting.

Description

Technical Field

[0001] The present invention relates to the technical field of water resource accounting, and in particular to a three-dimensional model method for calculating groundwater fissure flow, a device thereof, and a storage medium. Background Art

[0002] At present, the temporal and spatial distribution of water resources in my country is uneven, the per capita water resource share is still at a relatively low level internationally, and the situation of groundwater protection is relatively severe. Due to the immaturity of existing technologies, a series of groundwater environmental problems caused by oil extraction and excessive pollution of urban surface water are relatively prominent. Therefore, it is particularly important to protect my country's groundwater resources and scientifically and rationally develop and utilize existing groundwater resources. Dynamic analysis of groundwater flow in fractured rock masses and exploration of the temporal and spatial variation trends of groundwater are of great significance to my country's groundwater pollution prevention and control, groundwater resource management, etc.

[0003] Most existing methods for calculating groundwater fissure flow are limited to two-dimensional fracture networks, and often all groundwater flows in fracture networks are assumed to be laminar or turbulent flows for simulation, which will lead to huge errors and have a certain impact on subsequent groundwater pollution prevention and control and groundwater resource protection. Since real fractured groundwater often contains both laminar and turbulent states, it is urgent to develop a program that can automatically identify the real flow state of fractured groundwater and calculate fracture flow according to different calculation methods, which has an important impact on future groundwater resource protection. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a three-dimensional model method for calculating groundwater fissure flow and its equipment and storage medium, which can effectively solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a three-dimensional model method for calculating groundwater fissure flow, characterized in that it includes the following steps:

[0006] Step 1: Construct a three-dimensional fracture network and input the variables of the network;

[0007] Step 2: Set the node water head value and the fracture flow value of the network, and input the node water head value and the fracture flow value into the Reynolds number calculation formula to obtain the Reynolds number value;

[0008] Step 3: Substitute the Reynolds number into the equation to calculate the new node head value and fracture flow value;

[0009] Step 4: Use the Newton-Raphson iteration method to perform iterative calculations to obtain the differences between the node head and the fracture flow;

[0010] Step 5: If the difference between the node head and the fracture flow is less than 10 -5 , then the final node head and fracture flow value are output

[0011] Step 6: If the difference between the node head and the fracture flow is greater than or equal to 10 -5 , then proceed to step 2.

[0012] Preferably, the variables of the three-dimensional fracture network in step 1 include left-end water head, right-end water head, hydrodynamic viscosity, water density, fracture width and gravitational acceleration.

[0013] Preferably, the node head value and the fracture flow value are assumed arbitrary values.

[0014] Preferably, if the Reynolds number value in step 2 is less than or equal to 2300, it is substituted into the laminar flow equation; if the Reynolds number value is greater than 2300, it is substituted into the turbulent flow equation.

[0015] Preferably, the laminar flow equation is:

[0016]

[0017] Where ρ is the water density, g is the gravitational acceleration, and D i-j is the hydraulic radius of nodes i and j in the crack, μ is the dynamic viscosity of water, h i is the water head of node i, h j is the water head at node j, ΔL i-j is the crack length between nodes i and j.

[0018] Preferably, the turbulence equation is:

[0019]

[0020] Among them, g is the acceleration of gravity, D is the hydraulic radius, △h is the node head difference, △L is the crack length difference, ε is the roughness, μ is the dynamic viscosity of water, and ρ is the water density.

[0021] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the three-dimensional model method for calculating groundwater fracture flow as described above when executing the computer program.

[0022] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the three-dimensional model method for calculating groundwater fracture flow as described above.

[0023] Compared with the prior art, the present invention provides a three-dimensional model method for calculating groundwater fissure flow, a device and a storage medium thereof, which have the following beneficial effects:

[0024] 1. The present invention substitutes different node head values ​​and fracture flow values ​​for multiple times, and performs simulation calculations in three-dimensional discrete network models of different specifications, and substitutes them into appropriate equations for calculation. Compared with the traditional two-dimensional discrete fracture network and the single use of laminar flow equations or turbulent flow equations to simulate groundwater flow, the results calculated by this method are more accurate and efficient;

[0025] 2. The present invention can also be applied to two-dimensional fracture network flow. By adjusting specific program parameters, calculation results can be quickly obtained. Therefore, this method also has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a three-dimensional model method for calculating groundwater fissure flow rate according to the present invention;

[0027] Figure 2 A schematic diagram of groundwater laminar flow simulated by a regular three-dimensional fracture network of the present invention;

[0028] Figure 3 Schematic diagram of groundwater turbulent flow simulated by the regular three-dimensional fracture network of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] The present invention provides a three-dimensional model method for calculating groundwater fissure flow, which is characterized by comprising the following steps:

[0031] Step 1: Construct a three-dimensional fracture network and input the variables of the network;

[0032] Step 2: Set the node water head value and the fracture flow value of the network, and input the node water head value and the fracture flow value into the Reynolds number calculation formula to obtain the Reynolds number value;

[0033] Step 3: Substitute the Reynolds number into the equation to calculate the new node head value and fracture flow value;

[0034] Step 4: Use the Newton-Raphson iteration method to perform iterative calculations to obtain the differences between the node head and the fracture flow;

[0035] Step 5: If the difference between the node head and the fracture flow is less than 10 -5, then the final node head and fracture flow value are output

[0036] Step 6: If the difference between the node head and the fracture flow is greater than or equal to 10 -5 , then proceed to step 2.

[0037] Preferably, the variables of the three-dimensional fracture network in step 1 include the left end water head (h u )、Right end water head (h d ), water dynamic viscosity (μ), water density (ρ), crack width (b) and gravity acceleration (g). The variable values ​​are obtained by searching relevant data based on the characteristics of different fractured rocks. i is the node head value, Q i is the fracture flow value.

[0038] Preferably, the node head value and the fracture flow value may be any assumed values.

[0039] Preferably, if the Reynolds number value in step 2 is less than or equal to 2300, it is substituted into the laminar flow equation; if the Reynolds number value is greater than 2300, it is substituted into the turbulent flow equation.

[0040] Preferably, the laminar flow equation is:

[0041]

[0042] Where ρ is the water density, g is the gravitational acceleration, and D i-j is the hydraulic radius of nodes i and j in the crack, μ is the dynamic viscosity of water, h i is the water head of node i, h j is the water head at node j, ΔL i-j is the crack length between nodes i and j.

[0043] Preferably, the turbulence equation is:

[0044]

[0045] Among them, g is the acceleration of gravity, D is the hydraulic radius, △h is the node head difference, △L is the crack length difference, ε is the roughness, μ is the dynamic viscosity of water, and ρ is the water density.

[0046] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the three-dimensional model method for calculating groundwater fracture flow as described above when executing the computer program.

[0047] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the three-dimensional model method for calculating groundwater fracture flow as described above.

[0048] As a specific embodiment of the present invention:

[0049] Embodiment 1

[0050] First, a three-dimensional fracture network of arbitrary specifications is constructed, and the variables of the left end hydraulic head, right end hydraulic head, hydrodynamic viscosity, water density, fracture width and gravity acceleration of the network are defined. These variables are input into the program, and the hydraulic head values ​​and fracture flow values ​​of all nodes in the network are assumed. Among them, the assumed node hydraulic head and fracture flow are arbitrary values.

[0051] Secondly, the Reynolds number (Re) of each fracture flow is obtained by inputting the values ​​of the node head and fracture flow. According to the existing Reynolds number calculation formula Re = ρvd / μ, where ρ is the water density, v is the flow velocity of the fluid, d is a characteristic length, and μ is the dynamic viscosity of water. The flow velocity is calculated by the node head difference, which is related to the fracture flow. According to the value of the Reynolds number, it is substituted into the corresponding laminar flow equation or turbulent flow equation to calculate the new node head and fracture flow values.

[0052] Finally, the Newton-Raphson iteration method is used to iterate the calculation until the difference between the node head and the fracture flow obtained from the two calculations is less than 10. -5 When the last node head and fracture flow rate are output, the flow state of groundwater in each simulated fracture of the entire three-dimensional fracture network is evaluated according to the last node head and fracture flow rate.

[0053] Embodiment 2

[0054] See also Figure 2-3, the numbers 1-27 shown in the figure are all nodes. If a three-dimensional fracture network consisting of 27 nodes and 54 fractures is established (the network can be composed of any number of nodes and fractures). A higher water head is applied to the left side of the three-dimensional fracture network to make the groundwater flow from the left to the right. The flow state of each fracture is described by the groundwater flow equation. With the hydraulic heads at the inlet (nodes 1, 4, 7, 10, 13, 16, 19, 22, 25) and outlet (nodes 3, 6, 9, 12, 15, 18, 21, 24, 27) as boundary conditions, the hydraulic heads of internal nodes (h2, h5, h8, h11, h14, h17, h20, h23, h26) and inlet flow rates (Q1, Q4, Q7, Q10, Q13, Q16, Q19, Q22, Q25) and outlet flow rates (Q3, Q6, Q9, Q12, Q15, Q18, Q21, Q24, Q27), a total of 27 unknowns need to be solved iteratively. For this three-dimensional fracture network, 27 groundwater flow equations are established for the 27 unknown variables according to the mass conservation law of the 27 internal nodes, and the Newton-Raphson iteration method is used to solve the unknown hydraulic heads and flow rates. Taking node 14 as an example, the groundwater flow equation is:

[0055] Q 5-14 +Q 13-14 +Q 11-14 -Q 14-15 -Q 14-17 -Q 14-23 =0,

[0056] After inputting the initial assumed node head and flow, the corresponding Reynolds number is solved. If the program determines that Re≤2300, it is substituted into the laminar flow equation, which is:

[0057]

[0058] Where ρ is the water density, g is the gravitational acceleration, and D i-j is the hydraulic radius of nodes i and j in the crack, μ is the dynamic viscosity of water, h i is the water head of node i, h j is the water head at node j, ΔL i-j is the crack length between nodes i and j.

[0059] If the program determines that Re>2300, it substitutes into the turbulence equation, which is:

[0060]

[0061] Among them, g is the acceleration of gravity, D is the hydraulic radius, △h is the node head difference, △L is the crack length difference, ε is the roughness, μ is the dynamic viscosity of water, and ρ is the water density.

[0062] The water head and flow rate in the second iteration can be calculated by the obtained Reynolds number. Each fracture flow rate can be iteratively solved through the steps described in the present invention, and finally an accurate fracture flow rate can be obtained.

[0063] Embodiment 3

[0064] The three-dimensional model method for calculating groundwater fissure flow in the present invention is also applicable to the simulation of groundwater flow in a two-dimensional fracture network, where the threshold for distinguishing between laminar flow and turbulent flow is 100;

[0065] When Re≤100 (Re is the Reynolds number), substitute into the laminar flow equation, the laminar flow equation is:

[0066]

[0067] Among them, ρ is the water density, g is the gravitational acceleration, H is the crack width, μ is the dynamic viscosity of water, and h i is the water head of node i, h j is the water head at node j, ΔL i-j is the crack length of nodes i and j, and b is the crack aperture;

[0068] When Re>100 (Re is the Reynolds number), substitute it into the turbulence equation, which is:

[0069]

[0070] Among them, μ is the dynamic viscosity of water, k is the permeability coefficient, β is the inertial resistance coefficient, ρ is the water density, g is the gravitational acceleration, b is the crack aperture, H is the crack width, and for an ordinary crack, k = b2 / 12.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-dimensional model method for calculating groundwater fissure flow, characterized in that: The following steps are involved: Step 1: Construct a three-dimensional fracture network and input the variables of the network; Step 2: Set the node water head value and the fracture flow value of the network, and input the node water head value and the fracture flow value into the Reynolds number calculation formula to obtain the Reynolds number value; Step 3: Substitute the Reynolds number into the equation to calculate the new node head value and fracture flow value; Step 4: Use the Newton-Raphson iteration method to perform iterative calculations to obtain the differences between the node head and the fracture flow; Step 5: If the difference between the node head and the fracture flow is less than 10 -5 , then the final node head and fracture flow value are output Step 6: If the difference between the node head and the fracture flow is greater than or equal to 10 -5 , then proceed to step 2; The variables of the three-dimensional fracture network in step 1 include left end water head, right end water head, hydrodynamic viscosity, water density, fracture width and gravitational acceleration; The second step is to substitute the Reynolds number into the laminar flow equation or the turbulent flow equation according to the numerical value.

2. A three-dimensional model method for calculating groundwater fissure flow according to claim 1, characterized in that: The node head values ​​and fracture flow values ​​are assumed arbitrary values.

3. A three-dimensional model method for calculating groundwater fissure flow according to claim 1, characterized in that: In the step 2, if the Reynolds number value is less than or equal to 2300, it is substituted into the laminar flow equation; if the Reynolds number value is greater than 2300, it is substituted into the turbulent flow equation.

4. A three-dimensional model method for calculating groundwater fissure flow according to claim 3, characterized in that: The laminar flow equation is: , Where ρ is the water density, g is the gravitational acceleration, is the hydraulic radius of nodes i and j in the crack, μ is the dynamic viscosity of water, is the water head of node i, is the water head at node j, is the crack length between nodes i and j.

5. A three-dimensional model method for calculating groundwater fissure flow according to claim 3, characterized in that: The turbulence equation is: , Among them, g is the acceleration of gravity, D is the hydraulic radius, △h is the node head difference, △L is the crack length difference, ε is the roughness, μ is the dynamic viscosity of water, and ρ is the water density.

6. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the three-dimensional model method for calculating groundwater fracture flow as described in any one of claims 1 to 5 are implemented.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the three-dimensional model method for calculating groundwater fracture flow as claimed in any one of claims 1 to 5 are implemented.

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