A high-content waste gypsum body pipe resistance simulation prediction method

Abstract

The application provides a high-doped waste gypsum body pipe resistance simulation prediction method and relates to the technical field of mining filling. The method regards the high-doped waste gypsum body as a composite flow which is composed of a tailings cement slurry continuous phase and a waste rock discrete phase, determines rheological parameters of the tailings cement slurry and basic parameters of the waste rock, uses a viscous flow model to simulate the tailings cement slurry, discriminates whether the fluid is laminar flow or turbulent flow through a Reynolds number, further selects a corresponding viscous flow model, combines the rheological parameters of the tailings cement slurry to define the fluid by using a Herschel-Bulkley rheological model, simulates the waste rock, and finally bidirectionally couples simulation to predict the pipe resistance. The method can simulate the high-doped waste gypsum body, solves the problems that the traditional rheological test result is inaccurate, the pipe resistance calculation method using the theory is inaccurate, and the filling ring pipe test method is time-consuming and labor-consuming, can more simply obtain a relatively accurate result, and has the popularization and application value.

Description

Technical Field

[0001] This invention relates to the field of mining backfilling technology, and in particular to a method for simulating and predicting pipe resistance in high-content waste gypsum bodies. Background Technology

[0002] Currently, paste backfilling has become an important approach to green mine construction and has been widely applied in numerous mines both domestically and internationally. The calculation of slurry pipe resistance in backfilling plays a crucial role in hydraulic solid material transport engineering. In modern deep well backfilling, the friction resistance along the slurry pipeline is one of the key factors affecting pipeline design and stope backfilling quality. However, due to high waste rock content (i.e., when the ratio of waste rock to tailings reaches 40-60%), traditional rheological testing results are inaccurate, leading to inaccurate calculations of pipe resistance using theoretical methods. Furthermore, the backfilling loop test method is time-consuming and labor-intensive.

[0003] Therefore, the invention of a simulation and prediction method for pipe resistance of high-dosage waste gypsum can realize the rapid and relatively accurate calculation of pipe resistance of high-dosage waste gypsum, which facilitates the selection of pipe diameter, conveying speed, pressure reduction measures and full-pipe conveying measures, and the selection of wear-resistant pipe type, etc., and has great significance and promotion value. Summary of the Invention

[0004] To address the aforementioned technical problems in the existing technology, this invention provides a method for simulating and predicting the pipe resistance of high-dosage waste gypsum. The technical solution is as follows:

[0005] A method for simulating and predicting the pipe resistance of high-content waste gypsum, the method comprising:

[0006] S1. The high-content waste gypsum body is considered as a composite flow composed of a continuous phase of tailings cement slurry and a discrete phase of waste rock.

[0007] S2. Measure the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock respectively.

[0008] S3. Use a viscous flow model to simulate tailings cement slurry;

[0009] S4, Simulated waste rock;

[0010] S5. Bidirectional coupling simulation calculation of tube resistance.

[0011] The mass ratio of waste rock to tailings in the high-content waste gypsum is not less than 40%.

[0012] In step S2, the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock are determined experimentally.

[0013] The rheological parameters of the tailings cement slurry include: yield stress, viscosity, shear rate, as well as the density, flow rate, and concentration of the tailings cement slurry.

[0014] The basic parameters of the waste rock include: particle size, particle flow rate, non-uniformity coefficient, curvature coefficient, density, incident direction, and incident velocity.

[0015] In step S3, the Reynolds number is first calculated based on the density and flow velocity of the tailings cement slurry to determine whether the tailings cement slurry is laminar. The calculation formula is as follows:

[0016]

[0017] Where Re is the Reynolds number; ρ is the density of the tailings cement slurry, kg / m³. 3 u is the flow velocity of the tailings cement slurry, m / s; D is the inner diameter of the pipe, m; k is the viscosity, Pa·s;

[0018] If Re < 2320, the tailings cement slurry is laminar; otherwise, it is turbulent. The laminar flow is simulated using the laminar model in Viscous, and the turbulent flow is simulated using the k-epsilon model in Viscous. The tailings cement slurry is defined as a fluid material, and the Herschel-Bulkley rheological model is used. The measured rheological parameters of the tailings cement slurry are input to define the fluid.

[0019] The Herschel-Bulkley rheological model is as follows:

[0020] τ=τ y +kγ n

[0021] Where τ is the shear stress, Pa; τ y γ is the yield stress, Pa; γ is the shear rate, s. -1 n is the power law exponent. When n = 1, the Herschel-Bulkley rheological model is the Bingham model. Bingham fluid is defined, and the corresponding boundary conditions are input to simulate tailings cement slurry.

[0022] The corresponding boundary conditions are the velocity inlet condition and the pressure outlet condition of the tailings cement slurry; wherein, the velocity inlet condition is the flow velocity of the tailings cement slurry, and the pressure outlet condition is the static pressure of the tailings cement slurry flowing out of the pipe (since the outlet is connected to the atmosphere, the relative atmospheric pressure is 0, that is, the static pressure is 0).

[0023] In step S4, the waste rock is regarded as a discrete phase. Based on the measured basic parameters of the waste rock, one of the discrete models, such as DEM, DPM, DDPM, and MPM, is selected, and the relevant incident parameters and particle parameters are set to simulate the waste rock as discrete phase particles. The incident parameters include the incident direction and incident velocity, and the particle parameters are the particle size.

[0024] In step S5, the continuous phase of tailings cement slurry and the discrete phase of waste rock are bidirectionally coupled to simulate the composite flow. This is achieved by selecting the "Enable Interaction with Continuous Phase" option in the Particle Tracking panel of the MPM model, enabling bidirectional particle-fluid coupling calculation. Monitoring surfaces are then set according to actual needs, and the pressure values ​​at each monitoring surface are determined using the pressure contour map of the composite flow. The pipe resistance is then calculated using the following formula:

[0025]

[0026] Where i is the pipe resistance, Pa / m; p1 is the pressure near the pipe inlet monitoring surface, Pa; p2 is the pressure away from the pipe inlet monitoring surface, Pa; L is the pipe length, m. The positions of p1 and p2 are selected as needed, ensuring that p1 is near the pipe inlet monitoring surface and p2 is away from the pipe inlet monitoring surface.

[0027] The above solutions target pipes with the same inner diameter.

[0028] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0029] In the above scheme, the rheological parameters of tailings cement slurry and the basic parameters of waste rock are measured to simulate high-content waste rock paste, and then the pressure at various points is detected to calculate the pipe resistance, resulting in higher accuracy and greater convenience in pipe resistance calculation. Applying this invention, the simulated and predicted pressure and pipe resistance calculations for pipeline transportation of high-content waste rock paste can be realized, facilitating pipeline transportation design. Simultaneously, it avoids the inaccuracy of traditional rheological testing leading to inaccurate theoretical pipe resistance calculations in high-content waste rock situations, and the time-consuming and labor-intensive filling loop test method, thus reducing pipeline transportation costs. Based on this invention, it provides a theoretical basis for the design of paste-filled pipeline transportation, improves pipeline transportation efficiency, and saves filling costs, which is of significant value. The method of this invention is applicable to mining enterprises in the metal and non-metal sectors. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of a method for simulating and predicting the pipe resistance of high-content waste gypsum provided in an embodiment of the present invention;

[0032] Figure 2 This is a simulated longitudinal section of tailings cement slurry flow in an embodiment of the present invention;

[0033] Figure 3 This is a simulated cross-sectional view of tailings cement slurry flow in an embodiment of the present invention;

[0034] Figure 4 This is a simulation diagram of waste rock in an embodiment of the present invention;

[0035] Figure 5 This is a simulated longitudinal section of high-content waste gypsum in an embodiment of the present invention;

[0036] Figure 6 This is a pressure cloud map of the monitoring surface at 0.05m in an embodiment of the present invention;

[0037] Figure 7 This is a pressure cloud map of the monitoring surface at 0.95m in an embodiment of the present invention. Detailed Implementation

[0038] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0039] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0040] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0041] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0042] This invention provides a method for simulating and predicting the pipe resistance of high-content waste gypsum. For example... Figure 1 The flowchart shown below illustrates a method for simulating and predicting pipe resistance in high-content waste gypsum. This method may include the following steps:

[0043] S1. The high-content waste gypsum body is considered as a composite flow composed of a continuous phase of tailings cement slurry and a discrete phase of waste rock.

[0044] S2. Measure the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock respectively.

[0045] S3. Use a viscous flow model to simulate tailings cement slurry;

[0046] S4, Simulated waste rock;

[0047] S5. Bidirectional coupling simulation calculation of tube resistance.

[0048] The mass ratio of waste rock to tailings in the high-content waste gypsum is not less than 40%.

[0049] In step S2, the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock are determined experimentally.

[0050] The rheological parameters of the tailings cement slurry include: yield stress, viscosity, shear rate, as well as the density, flow rate, and concentration of the tailings cement slurry.

[0051] The basic parameters of the waste rock include: particle size, particle flow rate, non-uniformity coefficient, curvature coefficient, density, incident direction, and incident velocity.

[0052] In step S3, the Reynolds number is first calculated based on the density and flow velocity of the tailings cement slurry to determine whether the tailings cement slurry is laminar. The calculation formula is as follows:

[0053]

[0054] Where Re is the Reynolds number; ρ is the density of the tailings cement slurry, kg / m³. 3 u is the flow velocity of the tailings cement slurry, m / s; D is the inner diameter of the pipe, m; k is the viscosity, Pa·s;

[0055] If Re < 2320, the tailings cement slurry is laminar; otherwise, it is turbulent. The laminar flow is simulated using the laminar model in Viscous, and the turbulent flow is simulated using the k-epsilon model in Viscous. The tailings cement slurry is defined as a fluid material, and the Herschel-Bulkley rheological model is used. The measured rheological parameters of the tailings cement slurry are input to define the fluid.

[0056] The Herschel-Bulkley rheological model is as follows:

[0057] τ=τ y +kγ n

[0058] Where τ is the shear stress, Pa; τ y γ is the yield stress, Pa; γ is the shear rate, s. -1 n is the power law exponent. When n = 1, the Herschel-Bulkley rheological model is the Bingham model. Bingham fluid is defined, and the corresponding boundary conditions are input to simulate tailings cement slurry.

[0059] The corresponding boundary conditions are the velocity inlet condition and the pressure outlet condition of the tailings cement slurry.

[0060] In step S4, the waste rock is regarded as a discrete phase. Based on the measured basic parameters of the waste rock, one of the discrete models, such as DEM, DPM, DDPM, and MPM, is selected, and the relevant incident parameters and particle parameters are set to simulate the waste rock as discrete phase particles.

[0061] In step S5, the continuous phase of tailings cement slurry and the discrete phase of waste rock are bidirectionally coupled to simulate a composite flow, and monitoring surfaces are set up. The pressure values ​​of each monitoring surface are monitored by the pressure cloud map of the composite flow, and then the pipe resistance is calculated. The calculation formula is as follows:

[0062]

[0063] Where i is the pipe resistance, Pa / m; p1 is the monitoring surface pressure near the pipe inlet, Pa; p2 is the monitoring surface pressure away from the pipe inlet, Pa; and L is the pipe length, m.

[0064] The following description, in conjunction with specific embodiments, illustrates this point.

[0065] For a horizontal conduit filled with paste in a copper mine, the yield stress τ of the tailings cement slurry is... y The pressure is 79.798 Pa, the viscosity k is 1.489 Pa·s, and the density of the tailings cement slurry is 1796 kg / m³. 3 The horizontal pipe has a length L of 1m and an inner diameter D of 100mm. The flow velocity of the tailings cement slurry is calculated to be approximately 1m / s. According to the Bingham fluid Reynolds number calculation formula:

[0066]

[0067] Substituting the data, we get Re = 120.618, which is much smaller than 2320, indicating a laminar flow state.

[0068] Therefore, the laminar flow model in viscous flow was selected, and Bingham fluid was defined in the material options based on the measured rheological parameters of the tailings cement slurry. Boundary conditions were set with corresponding parameters for velocity inlet and pressure outlet. In this example, the velocity inlet parameter was 1 m / s, and since it was connected to the atmosphere, relative pressure was used. The pressure outlet parameter was set to 0. The simulation results are as follows: Figure 2 , Figure 3 As shown.

[0069] The average particle size of the waste rock is about 10 mm, and its density is 2692 kg / m³. 3The particles are randomly distributed within the pipe, so the MPM model was chosen to simulate the waste rock. The particle incidence model was set to volumetric incidence, with the incidence position (0, 0, 0) and the incidence direction set to the positive Y-axis. The incidence velocity was 1 m / s, and the particles were cylindrical with a pipe inner diameter of 100 mm. The inlet was set to velocity inlet, and the discrete simulation was set to Escape conditions. The results are as follows: Figure 4 As shown.

[0070] Finally, a two-way coupled simulation of the composite flow of high-dosage waste gypsum was performed, such as... Figure 5 The pressure values ​​at each monitoring point are determined based on the pressure cloud maps at two different locations: 0.05m and 0.95m. Figure 6 , Figure 7 As shown, P1 is 12646.488 Pa, P2 is 5688.6558 Pa, and the distance L between the two monitoring surfaces is 0.9 m. Substituting these values ​​into the calculation formula:

[0071]

[0072] The tube resistance can be calculated to be 7730.9247 Pa / m.

[0073] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for simulating and predicting the pipe resistance of high-content waste gypsum, characterized in that, The method includes: S1. The high-content waste gypsum body is considered as a composite flow composed of a continuous phase of tailings cement slurry and a discrete phase of waste rock. S2. Measure the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock respectively. S3. Use a viscous flow model to simulate tailings cement slurry; S4, Simulated waste rock; S5. Bidirectional coupling simulation calculation of tube resistance; The mass ratio of waste rock to tailings in the high-content waste gypsum is not less than 40%. In step S2, the rheological parameters of the tailings cement slurry and the basic parameters of the waste rock are determined experimentally. The rheological parameters of the tailings cement slurry include: yield stress, viscosity, shear rate, as well as the density, flow rate, and concentration of the tailings cement slurry. The basic parameters of the waste rock include: particle size, particle flow rate, non-uniformity coefficient, curvature coefficient, density, incident direction, and incident velocity. In step S4, the waste rock is regarded as a discrete phase. Based on the measured basic parameters of the waste rock, one of the discrete models, such as DEM, DPM, DDPM, and MPM, is selected, and the relevant incident parameters and particle parameters are set to simulate the waste rock as discrete phase particles. The incident parameters include the incident direction and incident velocity, and the particle parameters are the particle size. In step S5, the continuous phase of tailings cement slurry and the discrete phase of waste rock are bidirectionally coupled to simulate a composite flow. Monitoring surfaces are set according to actual needs, and the pressure values ​​of each monitoring surface are determined by the pressure cloud map of the composite flow. Then, the pipe resistance is calculated using the following formula: ； in, i Pipe resistance, Pa / m; p 1 represents the pressure near the monitoring surface at the pipe inlet, in Pa; p 2 represents the surface pressure at the location furthest from the pipeline inlet, measured in Pa. L The length of the pipe is in meters (m).

2. The method for simulating and predicting the pipe resistance of high-dosage waste gypsum as described in claim 1, characterized in that, In step S3, the Reynolds number is first calculated based on the density and flow velocity of the tailings cement slurry to determine whether the tailings cement slurry is laminar. The calculation formula is as follows: ； Where Re is the Reynolds number; ρ It is the density of the tailings cement slurry, kg / m³ 3 ; u It is the flow velocity of the tailings cement slurry, in m / s; D It is the inner diameter of the pipe, in meters (m). k It is viscosity, Pa·s; If Re < 2320, the tailings cement slurry is laminar; otherwise, it is turbulent. The laminar flow is simulated using the laminar model in Viscous, and the turbulent flow is simulated using the k-epsilon model in Viscous. The tailings cement slurry is defined as a fluid material, and the Herschel-Bulkley rheological model is used. The measured rheological parameters of the tailings cement slurry are input to define the fluid.

3. The method for simulating and predicting pipe resistance of high-dosage waste gypsum as described in claim 2, characterized in that, The Herschel-Bulkley rheological model is as follows: ； in, τ The shear stress is in Pa. τ y γ is the yield stress, Pa; γ is the shear rate, s. -1 n is the power law exponent. When n=1, the Herschel-Bulkley rheological model is the Bingham model. Bingham fluid is defined, and the corresponding boundary conditions are input to simulate tailings cement slurry.

4. The method for simulating and predicting the pipe resistance of high-dosage waste gypsum as described in claim 3, characterized in that, The corresponding boundary conditions are the velocity inlet condition of the tailings cement slurry, i.e., the flow velocity of the tailings cement slurry, and the pressure outlet condition, i.e., the static pressure of the tailings cement slurry flowing out of the pipe.

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