Gas-liquid jet analysis method

Abstract

The invention belongs to the technical field of jet testing, and particularly relates to a gas-liquid jet analysis method which comprises the following steps: constructing a nozzle, a jet medium and a soil model; performing mesh generation on the nozzle, the jet medium and the soil model to obtain a finite element mesh model of the nozzle, the jet medium and the soil; performing particle filling based on the finite element mesh model of the soil to form a discretized soil particle model; combining the finite element mesh model of the nozzle and the jet medium with the discretized soil particle model to form a coupling model; setting material parameters and a control equation of the coupling model; setting a boundary condition, a time step length and a second convergence condition of the coupling model; and performing coupling simulation calculation solution on the coupling model, judging whether a solution result meets a second convergence condition, and if so, outputting the solution result. According to the gas-liquid jet flow analysis method, a theoretical basis is provided for design and manufacturing of jet flow equipment, and the cycle of parameter design of the jet flow equipment can be shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of jet testing, and in particular relates to a gas-liquid jet analysis method. Background Art

[0002] Jet technology is a new technology that has developed rapidly in recent years. It has a simple system structure and low requirements for the working environment. Jet technology can currently be used in various fields such as cleaning, stripping, descaling, cutting, drilling, crushing, dephosphorization, casting sand cleaning, spraying, water injection, grouting and fire fighting.

[0003] It is extremely important to deeply study the impact mechanics of water jets and the influence of jet parameters on the impact effect. Currently, most existing water jet research uses on-site engineering parameter adjustment. This method not only requires frequent adjustment of various system parameters, but also fails to obtain the jet trajectory and scouring mechanism at the micro level, which limits the theoretical research of jet technology and the development of jet equipment. Summary of the Invention

[0004] The present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, embodiments of the present invention propose a gas-liquid jet analysis method that can determine the jet trajectory and scouring mechanism at the microscopic level, providing a theoretical basis for the design and manufacture of jet equipment and shortening the cycle of jet equipment parameter design.

[0005] An embodiment of the present invention provides a gas-liquid jet analysis method, comprising the following steps: Construct nozzle, jet medium and soil models; Meshing the nozzle, jet medium and soil models to obtain finite element mesh models of the nozzle, jet medium and soil; Perform particle filling based on the finite element mesh model of soil to form a discretized soil particle model; A coupled model is formed by combining the finite element mesh model of the nozzle and jet medium with the discretized soil particle model; Set the material parameters, governing equations, fluid unit velocity, pressure, and pressure gradient of the coupled model; Synchronously set the boundary conditions, time step, first convergence condition and second convergence condition of the coupling model, read the mesh nodes, unit information, velocity, density of the soil particle model and calculate the unit porosity; Update the fluid velocity field of the jet medium in the coupled model, and update the velocity and position of the soil particles; A finite element-discrete element coupling solver is set up to perform finite element solution on the coupling model, and determine whether the finite element solution result meets the first convergence condition. If so, the finite element solution result is imported into the coupling solver, and the resultant force and torque acting on the soil particles are solved to determine whether the discrete element cycle is completed. If so, the discrete element solution result is imported into the coupling solver; a coupled simulation calculation is performed on the coupling model to determine whether the solution result meets the second convergence condition. If so, the solution result is output.

[0006] In some embodiments, performing particle filling based on the finite element mesh model of soil to form a discretized soil particle model includes: Setting a first contact model between soil particles and a second contact model between soil particles and soil particle model boundaries; Set the particle filling parameters.

[0007] In some embodiments, the control equations include a continuity equation and a momentum equation, and the momentum equations include a gas phase momentum equation, a liquid phase momentum equation, a solid phase momentum equation, and a solid phase particle kinematic equation.

[0008] In some embodiments, the control equation further includes a particle drag model, and the particle drag model is a Gidaspow drag model.

[0009] In some embodiments, the material parameter is the density of the liquid medium 998 kg / m 3 , the viscosity of the liquid medium is 0.001003kg·m -1 ·s -2 , the density of the gas medium is 1.225kg / m 3 , the viscosity of the gas medium is 1.8×10 -5 kg·m -1 ·s -2 , soil density 2500kg / m 3 , soil viscosity 10kg·m -1 ·s -2 .

[0010] In some embodiments, setting the boundary conditions, time step and second convergence condition of the coupling model includes: The nozzle inlet boundary is set to pressure inlet with an inlet pressure of 1 MPa to 1.5 MPa, and the nozzle outlet boundary condition is set to pressure outlet with a pressure value of 101325 Pa; Set the wall boundary of the soil model to a no-slip fixed wall, all velocities to 0, and the interface between the jet medium and the soil to a penetrating interface; The time step is set to 1×10 -5 s, the second convergence condition is that the residual is less than or equal to 1×10-4 .

[0011] In some embodiments, performing coupled simulation calculations to solve the coupled model includes: Setting a solution model, wherein the solution model is an Euler multiphase flow turbulence model and a VOF model; Set the solver type, which is a coupled implicit solver; Set a solution algorithm, which is a Coupled algorithm based on pressure-velocity coupling. Set a relaxation coefficient in the Coupled algorithm, and set the discrete format of pressure in the solution algorithm to standard mode, and the discrete format of momentum, turbulent kinetic energy, and turbulent dissipation rate to first-order upwind.

[0012] In some embodiments, the gas-liquid jet analysis method further includes constructing multiple types of nozzle models, wherein the shapes and size parameters of the outlets of the multiple nozzle models are different, and the multiple nozzle models are matched with the parameters and ranges of the nozzles to form multiple nozzle models to be analyzed; Performing coupled simulation calculations on the plurality of nozzle models to be analyzed independently or in combination to obtain a plurality of sets of solution results; Based on multiple sets of solution results, orthogonal analysis is performed on various nozzle models to obtain the optimal parameter combination.

[0013] In some embodiments, the optimal parameter combination is verified on a test device, and the sampling result of the test device is compared with the solution result. If the comparison error is within a first preset condition, the optimal parameter combination is output.

[0014] In some embodiments, the gas-liquid jet analysis method further includes performing voltage regulation on the gas jet module in the test device, wherein the voltage regulation includes: Filter, dry and compress the gas to form compressed gas which is stored in the gas storage tank for use by the gas jet module; Set a target gas pressure value, collect real-time gas pressure values at the outlets of the first electric valve and the second electric valve in real time, compare the real-time gas pressure value with the target gas pressure value, and determine whether the comparison result meets the second preset condition. If not, adjust the opening of the first electric valve and / or the second electric valve.

[0015] The gas-liquid jet analysis method of the embodiment of the present invention can obtain the jet trajectory and scouring mechanism at the microscopic level, provide a theoretical basis for the design and manufacture of jet equipment, and can also shorten the cycle of jet equipment parameter design. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a gas-liquid jet analysis method according to an embodiment of the present invention; Figure 2 is a flow chart of a gas-liquid jet analysis method according to another embodiment of the present invention; Figure 3 is a logic block diagram of a gas-liquid jet analysis method according to an embodiment of the present invention; Figure 4 is a schematic diagram of a finite element mesh model of a nozzle, jet medium, and soil model according to an embodiment of the present invention; Figure 5 Schematic diagram of a discrete element soil particle model after particle filling according to an embodiment of the present invention; Figure 6 Schematic diagram of six nozzle models according to an embodiment of the present invention; Figure 7 Figure 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the first working condition and an inlet pressure of 1 MPa, where (a) is an A-1 nozzle, (b) is an A-2 nozzle, (c) is a B-1 nozzle, (d) is a B-2 nozzle, (e) is a C-1 nozzle, and (f) is a C-2 nozzle; Figure 8 Figure 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the first working condition and an inlet pressure of 1.5 MPa, where (a) is an A-1 nozzle, (b) is an A-2 nozzle, (c) is a B-1 nozzle, (d) is a B-2 nozzle, (e) is a C-1 nozzle, and (f) is a C-2 nozzle; Figure 9 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the second working condition and the inlet pressure of 1 MPa, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle; Figure 10 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the second working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 11 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the third working condition and an inlet pressure of 1 MPa, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle; Figure 121. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the third working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 13 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the fourth working condition and an inlet pressure of 1 MPa, where (a) is an A-1 type nozzle, (b) is an A-2 type nozzle, (c) is a B-1 type nozzle, (d) is a B-2 type nozzle, (e) is a C-1 type nozzle, and (f) is a C-2 type nozzle; Figure 14 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the fourth working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 15 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the fifth working condition and an inlet pressure of 1 MPa, where (a) is an A-1 type nozzle, (b) is an A-2 type nozzle, (c) is a B-1 type nozzle, (d) is a B-2 type nozzle, (e) is a C-1 type nozzle, and (f) is a C-2 type nozzle; Figure 16 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the fifth working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 17 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the sixth working condition and an inlet pressure of 1 MPa, where (a) is an A-1 type nozzle, (b) is an A-2 type nozzle, (c) is a B-1 type nozzle, (d) is a B-2 type nozzle, (e) is a C-1 type nozzle, and (f) is a C-2 type nozzle; Figure 18 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the sixth working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 191 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the seventh working condition and an inlet pressure of 1 MPa, where (a) is an A-1 type nozzle, (b) is an A-2 type nozzle, (c) is a B-1 type nozzle, (d) is a B-2 type nozzle, (e) is a C-1 type nozzle, and (f) is a C-2 type nozzle; Figure 20 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the seventh working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 21 1 is a cloud diagram of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the eighth working condition and an inlet pressure of 1 MPa, where (a) is an A-1 type nozzle, (b) is an A-2 type nozzle, (c) is a B-1 type nozzle, (d) is a B-2 type nozzle, (e) is a C-1 type nozzle, and (f) is a C-2 type nozzle; Figure 22 1. The nephograms of the sediment volume fraction of the six nozzle models of the embodiment of the present invention under the eighth working condition and an inlet pressure of 1.5 MPa are shown, where (a) is the A-1 nozzle, (b) is the A-2 nozzle, (c) is the B-1 nozzle, (d) is the B-2 nozzle, (e) is the C-1 nozzle, and (f) is the C-2 nozzle. Figure 23 : These are curves showing the influence of jet characteristics on the scouring effect under different working media and different target distances in the embodiment of the present invention, wherein (a) is the working medium of air, the target distance is 20 cm, and the inlet pressure is 1 MPa; (b) is the working medium of liquid, the target distance is 20 cm, and the inlet pressure is 1 MPa; (c) is the working medium of air, the target distance is 35 cm, and the inlet pressure is 1.5 MPa; and (d) is the working medium of air, the target distance is 35 cm, and the inlet pressure is 1.5 MPa. Figure 24 This is a comparison of the jet characteristics and scouring effects of the A-1 type double nozzles according to the embodiment of the present invention when they intersect at 15°, 30°, or 45°, where (a) is 15°, (b) is 30°, and (c) is 45°; Figure 25 This is a comparison chart of the jet characteristics and scouring effects of the C-1 type double nozzle at 15°, 30°, or 45° according to an embodiment of the present invention, where (a) is 15°, (b) is 30°, and (c) is 45°; Figure 26 This is a cloud diagram comparing the jet characteristics and scouring effects of the first experimental element of an embodiment of the present invention, wherein the (a) frame shows the A-1 type double nozzle, the (b) frame shows the B-2 type double nozzle, and the (c) frame shows the C-1 type double nozzle; Figure 27 This is a cloud diagram comparing the jet characteristics and scouring effects of the second experimental element of an embodiment of the present invention, wherein the (a) frame shows the A-1 type double nozzle, the (b) frame shows the B-2 type double nozzle, and the (c) frame shows the C-1 type double nozzle; Figure 28 Comparison cloud maps of jet characteristics and scouring effects under the fourth experimental factor of an embodiment of the present invention and at 1 MPa, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, and (e) is a screenshot of a top view at a depth of 600 mm. Figure 29 Comparison cloud maps of jet characteristics and scouring effects under the fourth experimental factor of an embodiment of the present invention and at 1.5 MPa, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 30 Comparison cloud maps of jet characteristics and scouring effects under the fifth experimental element of an embodiment of the present invention at a target distance of 100 cm, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, and (e) is a screenshot of a top view at a depth of 600 mm. Figure 31 Comparison cloud maps of jet characteristics and scouring effects under the fifth experimental element of an embodiment of the present invention at a target distance of 300 cm, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, and (e) is a screenshot of a top view at a depth of 600 mm. Figure 32 Comparison cloud maps of jet characteristics and scouring effects under the sixth experimental factor of an embodiment of the present invention at an incident angle of 15°, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 33 Comparison cloud maps of jet characteristics and scouring effects under the sixth experimental factor of an embodiment of the present invention at an incident angle of 22.5°, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 34Figure 1 is a comparison of the jet characteristics and scouring effects under the 1 MPa working condition under the seventh experimental element of an embodiment of the present invention, wherein (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of the top view at a depth of 400 mm, (e) is a screenshot of the top view at a depth of 600 mm, and (f) is a screenshot of the top view at a depth of 800 mm. Figure 35 Comparison cloud maps of jet characteristics and scouring effects under 1.5 MPa conditions under the seventh experimental element of an embodiment of the present invention, where (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 36 The figures are cloud maps comparing the jet characteristics and scouring effects under the eighth experimental element of an embodiment of the present invention at a target distance of 100 cm, wherein (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 37 3. Comparison cloud maps of jet characteristics and scouring effects under the eighth experimental element of an embodiment of the present invention at a target distance of 300 cm, wherein (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm. Figure 38 Comparison cloud maps of jet characteristics and scouring effects under the condition of an incident angle of 15° under the ninth experimental element of an embodiment of the present invention, wherein (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm; Figure 39 Comparison cloud maps of jet characteristics and scouring effects under the condition of an incident angle of 22.5° under the ninth experimental element of an embodiment of the present invention, wherein (a) is a velocity cloud map, (b) is a volume cloud map, (c) is a three-dimensional map, (d) is a screenshot of a top view at a depth of 400 mm, (e) is a screenshot of a top view at a depth of 600 mm, and (f) is a screenshot of a top view at a depth of 800 mm; Figure 40 This is a comparison of the jet characteristics and scouring effects of the nozzle spinning jet under the tenth experimental factor of the embodiment of the present invention. (a) is a velocity cloud map, (b) is a three-dimensional map, and (c) is a top view of a pit with a depth of 1.12 meters. Figure 41Comparison cloud maps of jet characteristics and scouring effects under the same time and fixed-point spraying conditions under the tenth experimental element of an embodiment of the present invention, where (a) is a velocity cloud map, (b) is a three-dimensional map, and (c) is a top-down view of a pit with a depth of 0.84 meters. Figure 42 Comparison cloud diagrams of jet characteristics and scouring effects under the tenth experimental element of the embodiment of the present invention under the double-time fixed-point spraying condition, where (a) is a velocity cloud diagram, (b) is a three-dimensional diagram, and (c) is a top-down view of a pit with a depth of 1.12 meters. Figure 43 VOF model schematic diagram of an embodiment of the present invention; Figure 44 1 is a schematic diagram of a nozzle, jet medium, and soil model after fluid filling according to an embodiment of the present invention; Figure 45 Figure 1 is a diagram showing the particle states at different times of the double nozzles of an embodiment of the present invention, where the jet medium is water and the jet velocity is 30 m / s. (a) is a schematic diagram at the time node of 0.01, (b) is a schematic diagram at the time node of 0.02, (c) is a schematic diagram at the time node of 0.03, (d) is a schematic diagram at the time node of 0.04, (e) is a schematic diagram at the time node of 0.05, and (f) is a schematic diagram at the time node of 0.056. Figure 46 1 is a cross-sectional view of the particle state at different times when the dual-nozzle jet medium of the embodiment of the present invention is water and the jet velocity is 30 m / s, wherein (a) is a schematic diagram of the time node 0.01, (b) is a schematic diagram of the time node 0.02, (c) is a schematic diagram of the time node 0.03, (d) is a schematic diagram of the time node 0.04, (e) is a schematic diagram of the time node 0.05, and (f) is a schematic diagram of the time node 0.056; Figure 47 The jet velocity of the embodiment of the present invention is 20 m / s, and the velocity vector cloud diagram of the jet medium, wherein the jet medium in (a) is air and water, and the jet medium in (b) is water; Figure 48 The jet velocity of the embodiment of the present invention is 20m / s, and the jet media are air and water. The (a) is the front view cloud map, and (b) is the top view cloud map. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0018] like Figures 1 to 48 As shown, the gas-liquid jet analysis method according to an embodiment of the present invention includes the following steps: S100. Construct nozzle, jet medium and soil models.

[0019] It should be noted that the nozzle, jet medium and soil models are first modeled separately, and then the three models are combined to form an overall coupled model.

[0020] S200 , meshing the nozzle, jet medium, and soil models to obtain finite element mesh models of the nozzle, jet medium, and soil.

[0021] It should be noted that the physical preference for meshing the fluid region is set to CFD. This means that the region of the jet medium is set to CFD, and the solver is FLUENT. The mesh size, displacement, and smoothness are then set accordingly. The settings for these physical quantities can be determined based on the desired model accuracy. The appropriate mesh type is selected based on the characteristics of the different models. The entire coupled model is meshed to obtain a finite element mesh model with 356,039 grid cells and 573,828 nodes. The resulting mesh file is saved and stored in the created Edem and Fluent folders, respectively, in preparation for multiphase flow coupling.

[0022] S300: performing particle filling based on the finite element mesh model of soil to form a discretized soil particle model.

[0023] It should be noted that the finite element mesh model of the soil was populated with particles using Edem software. The particle generation method was set to a random particle factory, with the actual particle radius set to 0.8 to 1.5 times the base radius. The material of the soil model's boundaries and bottom was set to steel. The saved mesh file was then imported into Edem software to create a soil particle bed. The finite element mesh model of the soil was populated with particles, generating 429,120 particles. The coupling interface was then enabled, ready for integration into the Fluent software.

[0024] In addition, it should be noted that the mesh size of the jet medium is at least 3 times larger than the particle diameter, and the mesh volume is at least 10 times larger than the particle volume.

[0025] like Figure 2 As shown in the figure, the three-phase flow coupling is completed, and the coupling function successfully introduces the particle phase in EDEM into fluent for flow field calculation.

[0026] S400, combines the finite element mesh model of the nozzle and jet medium with the discretized soil particle model to form a coupling model.

[0027] It should be noted that the discretized soil particle model filled with particles, the finite element model of the nozzle and the jet medium are imported into Fluent, and the fluid mechanics analysis software Fluent is used to perform pre-processing, numerical calculation and post-processing of the jet simulation to finally form a coupled model.

[0028] S500: Set the material parameters, control equations, fluid unit velocity, pressure, and pressure gradient of the coupling model.

[0029] It should be noted that the material parameters and control equations of the nozzle model, jet medium model and soil model are set in the fluid mechanics analysis software Fluent, and the unit velocity, pressure and pressure gradient of the fluid are calculated.

[0030] For example, the unit velocity of the fluid can be 30 m / s, the pressure is less than or equal to 5 MPa, and the pressure gradient is less than or equal to 0.5 MPa, 1 MPa, or 1.5 MPa. S600: Synchronously set the boundary conditions, time step, first convergence condition and second convergence condition of the coupling model, read the grid nodes, unit information, velocity, density of the soil particle model and calculate the unit porosity.

[0031] It should be noted that the time step size of the Fluent calculation is several times the size of the Edem calculation time step. Several Edem cycles will be performed in each Fluent time step, and the particle information obtained after the cycle is completed will be called for calculation in the next Fluent time step.

[0032] The discrete element analysis software EDEM is used to read the mesh nodes, unit information, velocity and soil density of the soil particle model and calculate the unit porosity.

[0033] It should be noted that while Fluent sets the boundary conditions, time step, and first convergence conditions of the coupled model, it uses EDEM to synchronously read the mesh nodes, unit information, velocity, density of the soil particle model and calculate the unit porosity.

[0034] S700: Update the fluid velocity field of the jet medium in the coupled model, and update the velocity and position of the soil particles.

[0035] It should be noted that Fluent is used to update the fluid velocity field of the jet medium, and EDEM is used to update the movement velocity and position of the soil particles. For example, the fluid velocity field of the jet medium in the coupled model can be updated simultaneously with the velocity and position of the soil particles in EDEM, thereby improving the analysis effect and the accuracy of the collaboration between the two.

[0036] S800, setting a finite element-discrete element coupling solver, performing finite element solution on the coupling model, determining whether the finite element solution result satisfies the first convergence condition, if so, importing the finite element solution result into the coupling solver, and solving the resultant force and moment acting on the soil particles, determining whether the discrete element cycle is completed, if so, importing the discrete element solution result into the coupling solver.

[0037] It should be noted that if the finite element solution does not meet the first convergence condition, the control equation parameters of the coupling model or the momentum equation parameters are adjusted, or the control equation and momentum equation parameters are adjusted at the same time, and recalculation is performed.

[0038] It should be noted that the first convergence condition can be that the residual is less than or equal to 1×10 -4 .

[0039] If the discrete element cycle is not completed, the soil particle model mesh nodes, unit information, velocity and density are reread and the unit porosity is recalculated.

[0040] It should be noted that when the properties of soil particles are added to the finite element calculation in the form of momentum sinks in the finite element and discrete element coupled solvers, the discrete element solution results serve as the basis for the calculation of the momentum source phase equation and porosity in the coupled solver, as well as the fluid drag acting on the particles.

[0041] S900 , performing coupled simulation calculations on the coupled model to solve the coupled model, and determining whether the solution meets the second convergence condition, and outputting the solution if so.

[0042] It should be noted that the particle phase is simulated and solved by discrete element software Edem, and the fluid phase is simulated and solved by Fluent software, thereby achieving the purpose of coupled calculation.

[0043] After the simulation begins, the particles and the jet medium are initialized, and then the porosity and interphase forces are calculated. In Edem, the particles are first judged for contact, and then the particle parameters are substituted into the equation to solve the particle contact force and contact torque. Combined with the previous interphase force calculation, the resultant force and torque acting on the particles are obtained, and information such as particle velocity, position, and orientation is obtained, and the particle information is updated. After each Edem time step, a judgment is made. If the Fluent time step is completed, the calculation of porosity and interphase forces is returned; if the Fluent time step is not completed, the calculation of the next Edem time step is performed until the Fluent time step is completed. Each Fluent time step contains several iterations. In each iteration, the mass and momentum conservation equations are solved and the pressure is corrected. After the flow field calculation converges, the flow field information is updated and the next Fluent time step calculation begins. It can be summarized as follows: (1) During Edem-Fluent coupling calculations, Edem's coupling module is built into the Fluent software, and the two are seamlessly connected; (2) Edem can automatically read the grid in Fluent; (3) Edem can use the discrete phase model and Euler multinomial flow model in Fluent for multiphase flow coupling; (4) Edem is used to directly simulate particle motion; (5) Fully bidirectional dynamic coupling.

[0044] In addition, if the second convergence condition is not met, the simulation calculation is continued.

[0045] In some embodiments, performing particle filling based on the finite element mesh model of soil to form a discretized soil particle model includes: S301 , setting a first contact model between soil particles and a second contact model between soil particles and the boundary of the soil particle model.

[0046] It should be noted that the first contact model between soil particles is the Hertz-Mindlin with JKR contact model, which is used to set the interaction between soil particles. The second contact model is the Hertz-Mindlin no-slip contact model, which is used to limit the interaction between soil particles and the surrounding boundaries and the bottom boundary.

[0047] S302: Set particle filling parameters.

[0048] It should be noted that the particle generation method is set to a random particle factory, and the actual particle radius is 0.8 to 1.5 times the base radius. The material of the boundaries and bottom of the soil model is set to steel.

[0049] In some embodiments, the control equations include a continuity equation and a momentum equation, and the momentum equations include a gas phase momentum equation, a liquid phase momentum equation, a solid phase momentum equation, and a solid phase particle kinematic equation.

[0050] For example, the continuity equation is as follows:

[0051] Where: q can be replaced by f or s, f represents the water phase, s represents the sediment phase; is the volume fraction of each phase; is the density of each phase; is the velocity of each phase.

[0052] Treating the gas phase as an ideal gas and considering the action and reaction forces between the gas flow and the solid particles, the gas flow is solved using the Navier-Stokes equations in an Eulerian framework that takes porosity into account. Particle motion is solved using Newton's second law in a Lagrangian framework. Applying the ideal state gas equation for air, the mass and momentum conservation equations in the gas phase momentum equation are: =0 =- + + - S Where, 、 ,t, 、 、 、 , respectively: porosity, average fluid velocity, time, fluid density, pressure, viscosity, and gravitational acceleration, S Represents the airflow phase source term, which is the sum of the fluid resistance acting on the grid cells.

[0053] S =

[0054] Where, For the The resistance of each particle to the airflow, is the grid cell volume.

[0055] The liquid phase momentum equation is shown below:

[0056] in, is the volume fraction of the water phase, is the water phase density, is the water phase velocity, For pressure, is the water flow tangential stress tensor, is the interphase momentum exchange coefficient, is the solid phase velocity.

[0057] The solid phase momentum equation is shown below:

[0058] in: is the volume fraction of the sediment phase, is the density of the sediment phase, is the sediment phase velocity, is the water pressure, = is the interphase momentum exchange coefficient, is the source term of the sediment phase, is the pressure of the sediment phase, reflecting the mutual collision between particles. is the sediment tangential stress tensor, expressed as

[0059] in: is the shear viscosity of each phase, is the bulk viscosity of each phase.

[0060] It should be noted that Water flow tangential stress tensor The calculation formula is to replace q with f in the calculation formula of sediment tangential stress tensor.

[0061] For liquid-solid mixed flows, the interphase momentum exchange coefficient can be written in the following general form:

[0062] in: Represents different exchange coefficient models, is the particle relaxation time, is the volume fraction of the sediment phase, is the density of sediment phase, which is expressed as

[0063] is the shear viscosity of the aqueous phase.

[0064] Improved k- The model increases the interaction between phases and their turbulent kinetic energy and dissipation rate The equations are:

[0065]

[0066] Where, is the dissipation rate, is the turbulent kinetic energy caused by the mean velocity gradient, is the dissipation rate The turbulent Prandtl number, is a constant, Respectively reflect the influence of sediment phase on water phase, is the shear viscosity of the water phase at a certain node.

[0067] In some embodiments, the control equation further includes a particle drag model, and the particle drag model is a Gidaspow drag model.

[0068] It should be noted that the calculation formula of the drag model is as follows: =

[0069] Where: is the drag force of the Gidaspow mode; are the velocities of the fluid and particles, respectively, is the particle volume; is the porosity; is the momentum phase transfer coefficient, which is calculated as follows: 0.8

[0070] Where: is the particle diameter; is the drag coefficient related to the particle Reynolds number and is calculated as:

[0071] =

[0072] Where: is the particle Reynolds number.

[0073] Mesh porosity Refers to the ratio of the pore volume in the calculation grid to the grid volume. If the grid size is set to n times the particle diameter and the particles are assumed to be spherical, the porosity The relationship with the grid size is: =1-

[0074] When the mesh size is 1-3 times the particle size, the porosity increases significantly. When the mesh size is more than 3 times the particle size, the change in porosity slows down and tends to be stable. Therefore, the fluid domain mesh size should be at least 3 times larger than the particle diameter.

[0075] In some embodiments, the material parameter is the density of the liquid medium 998 kg / m 3 , the density and viscosity of the liquid medium are 0.001003kg·m -1 ·s -2 , the density of the gas medium is 1.225kg / m 3 , the viscosity of the gas medium is 1.8×10 -5 kg·m -1 ·s -2 , soil density 2500kg / m 3 , the viscosity of soil is 10 kg·m -1 ·s -2 .

[0076] In some embodiments, setting the boundary conditions, time step, first convergence condition, and second convergence condition of the coupling model includes: S601. Set the nozzle inlet boundary to a pressure inlet with an inlet pressure of 1 MPa to 1.5 MPa. Set the nozzle outlet boundary condition to a pressure outlet with a pressure value of 101325 Pa.

[0077] It should be noted that the inlet pressure of the nozzle inlet boundary can be set to 1 MPa, 1.2 MPa or 1.5 MPa. For example, when the jet medium is water, the water jet inlet pressure is 1 MPa or 1.5 MPa, and the air jet inlet pressure is 1 MPa or 1.5 MPa.

[0078] S602: Set the wall boundary of the soil model to a non-slip fixed wall, set all velocities to 0, and set the interface between the jet medium and the soil to a penetration interface.

[0079] It should be noted that the interface between the jet medium and the soil is set as a penetrable interface so that node information can be transmitted.

[0080] S603, the time step is set to 1×10 -5 s, the first and second convergence conditions can be that the residual is less than or equal to 1×10 -4 .

[0081] In some embodiments, performing coupled simulation calculations to solve the coupled model includes: S901. Setting a solution model, wherein the solution model is an Euler multiphase flow turbulence model and a VOF model.

[0082] The VOF model simulates two or more immiscible fluids by solving a single momentum equation and tracking the volume fraction of each fluid in the region. Typical applications include the prediction of jet breakup, the motion of large bubbles in liquids, the motion of liquids after dam break, and the steady-state or transient tracking of any gas-liquid interface. The VOF model relies on the fact that two or more fluids (or phases) do not penetrate each other. For each additional phase added to the model, a variable is introduced: the volume fraction of that phase in the calculation cell. In the gas-liquid-solid three-phase coupling, the fluid properties such as density and dynamic viscosity coefficient are related to the volume fraction of gas and liquid in each grid. For each additional phase to be added to the model, a variable is introduced, namely the volume fraction of the phase in the calculation cell. In each control volume, the sum of the volume fractions of all phases is 1. The domain of all variables and their properties is shared by all phases and represents the volume average, as long as the volume fraction in each direction is known at each location. The variables and their properties in any given cell either represent a pure phase or a mixture of phases, depending on the volume fraction value. If the first The volume fraction of the phase fluid is recorded as , satisfying the following three conditions, =0: No. The phase fluid is empty in the cell.

[0083] =1: No. The phase fluid is filled in the cell.

[0084] 1: The unit contains The interface between a phase fluid and one phase or other multiphase fluids.

[0085] =(1- ) • + •

[0086] =(1- ) • + •

[0087] =

[0088] In the formula, subscript f, , g represent solid, liquid and gas respectively, is the liquid volume fraction, is the density, μ is the dynamic viscosity coefficient. The motion of the phase interface can be obtained by solving the continuity equation with respect to the volume fraction of the liquid phase. Figure 43 As shown in the figure, schematic diagram of the VOF model: blue represents fluid 1, white represents fluid 2, and the red line represents the phase interface.

[0089] The time step is a key factor affecting numerical calculations. If it is too small, the computation will be very large. If it is too large, the calculation will diverge. Determine the time step according to the empirical formula =

[0090] in, +0.8766, is Poisson's ratio, G is the shear modulus, is the particle density, For the minimum diameter of the particles, a dynamic model of fluid and particles is established. By solving the momentum equation, the two-way coupling of fluid and particles is realized, and the mixing of gas-liquid-solid three-phase flow is studied to reveal the role of three-phase coupling in the complex mixing process.

[0091] S902: Set the solver type, which is a coupled implicit solver.

[0092] S903. Set a solution algorithm, which is a Coupled algorithm based on pressure-velocity coupling. Set the relaxation coefficient in the Coupled algorithm. The discrete format of the pressure in the solution algorithm is the standard mode, and the discrete format of the momentum, turbulent kinetic energy, and turbulent dissipation rate is the first-order upwind mode.

[0093] It should be noted that after setting the solution algorithm, the coupling model needs to be initialized. The initialization is set to mixed initialization. When the initialization is successful, the monitoring curve is set and the initialization calculation is performed from the jet inlet end, thereby improving the simulation calculation accuracy of the entire coupling model.

[0094] In some embodiments, the gas-liquid jet analysis method further comprises: S1000 , constructing multiple types of nozzle models, wherein the shapes and size parameters of the outlets of the multiple nozzle models are different, and matching the multiple nozzle models with the parameters and ranges of the nozzles to form multiple nozzle models to be analyzed.

[0095] like Figure 6 As shown, the embodiment of the present invention models 6 nozzles of different shapes and sizes, and numbers them respectively to form A-1, A-2, B-1, B-2, C-1, and C-2.

[0096] It should be noted that the structural dimensions of the nozzle will significantly affect the flushing jet characteristics. The present invention is an embodiment that obtains the optimal nozzle shape and size parameters by comparing nozzles with different diameter ratios, different expansion angles, and different outlet diameters.

[0097] Assume that the inlet diameter of the nozzle is D1, the outlet diameter of the nozzle is D, the length of the nozzle is L, and D1=60mm, where A-1's L / D=1, A2's L / D=2 is A2, the cone expansion angle B-1 of the B-type nozzle is 45°, B-2 is 30°, the nozzle outlet diameter D=20mm, and the funnel expansion angle C-1 of the C-type nozzle is 45°, C-2 is 30°. The six types of nozzles can basically be summarized as right-angle, conical, and funnel-type. The main factors affecting fixed-point sand flushing are jet velocity Uo, jet diameter d, flushing target distance, and sediment particle size Ds. According to the large-scale moving jet flushing test, the dimensionless gully depth has a hyperbolic relationship with the jet / moving velocity. According to jet theory knowledge, among them: is the theoretical jet flow rate, L / min; d is the nozzle orifice diameter (equivalent diameter), mm; P is the jet pressure, MPa V is the jet velocity, m / s; P is the jet pressure, MPa; is the density of the jet medium, g / cm3 Where q is the flow rate through the nozzle, m 3 / s; VFlow velocity at nozzle outlet, m / s; Nozzle correction coefficient. In actual jet operation conditions, the actual flow rate through the nozzle is less than the theoretical value, and there is an empirical coefficient ,For example, =0.95.

[0098] First, six nozzle configurations were designed. Combinations of these six nozzle configurations were tested at different inlet pressures at target distances (submerged depths) of 20 cm and 35 cm, respectively. Water jet inlet pressures were 1 MPa and 1.5 MPa, while air jet inlet pressures were 1 MPa and 1.5 MPa. Combinations of these tests were conducted with the nozzle at angles of 30° and 45° to the water surface, and at a target distance (submerged depth) of 20 cm, with water and air jet forces of 1 MPa and 1.5 MPa, respectively. The following assumptions and simplifications were made in the flow field analysis of the embodiments of the present invention: 1. The flow field is stable, with parameters remaining constant over time. 2. The fluid is incompressible, with density and viscosity remaining constant over time. 3. No heat transfer issues are involved.

[0099] S1100 , performing coupled simulation calculations on multiple nozzle models to be analyzed independently or in combination to obtain multiple groups of solution results.

[0100] like Figures 7 to 22 As shown in the figure, when independent simulation calculations are performed on multiple nozzle models, simulation calculations of multiple nozzles under eight different working conditions can be used. By comparing the volume fractions of different nozzle models under different working conditions, the influence of different parameters on the injection efficiency can be obtained.

[0101] For example, the eight different working conditions are: The first working condition is: the submerged water depth is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 90°, and the jet medium is water jet.

[0102] The second working condition is: the submerged water depth is 35 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 90°, and the jet medium is water jet.

[0103] The third working condition is: the jet target distance is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 45°, and the jet medium is water jet.

[0104] The fourth working condition is: the jet target distance is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 30°, and the jet medium is water jet.

[0105] The fifth working condition is: the submerged water depth is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 90°, and the jet medium is air jet.

[0106] The sixth working condition is: the submerged water depth is 35 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 90°, and the jet medium is air jet.

[0107] The seventh working condition is: the jet target distance is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 45°, and the jet medium is air jet.

[0108] The eighth working condition is: the jet target distance is 20 cm, the nozzle model inlet pressure is 1 MPa and 1.5 MPa, the angle between the nozzle and the water surface is 30°, and the jet medium is air jet.

[0109] It should be noted that the injection and loosening of the soil model. First, the vertical invasion model is used to estimate the invasion depth; it is assumed that the depth of the jet medium into the soil is such that the thrust pressure is approximately equal to 6 times the soil cohesion.

[0110] The jet medium has an initial flow rate After being ejected from the orifice, a discontinuous velocity surface is formed between the jet and the surrounding static fluid. The velocity discontinuity surface is unstable and will inevitably produce fluctuations and develop into vortices, thereby causing turbulence. This will draw the fluid that was originally in a static state around it into the jet, forming the entrainment phenomenon of the jet. As the turbulence develops, the amount of fluid that is entrained and moves with the jet continues to increase, the jet boundary gradually expands to both sides, and the flow rate increases along the way. Due to the mixing of the surrounding static fluid and the jet, a corresponding resistance to the jet is generated, which reduces the flow velocity at the edge of the jet and makes it difficult to maintain the original initial flow velocity. The mixing of the jet and the surrounding fluid gradually develops from the edge to the center, and after a certain distance, it develops to the center of the jet. From then on, turbulence develops on the entire cross-section of the jet. The mixing zone that expands inward and outward from the orifice boundary is called the shear layer or mixing layer. The central part is not affected by the mixing and still maintains the original outlet flow velocity. The area between the orifice and the end of the potential core is called the potential core of the jet. The section from the orifice to the end of the potential core is called the initial section of the jet (zone of flow establishment). The jet after the turbulence is fully developed is called the main section of the jet (zone of established flow).

[0111] The velocity distribution of each section shows similar properties, with the velocity being the largest on the axis and decreasing as the distance from the axis increases. and the transverse coordinates on the cross section Dimensionless coordinates and If it is represented by , the dimensionless velocity distribution on all sections falls on the same curve. represents the flow velocity at any section at a distance y from the axis, is the axial flow velocity of the section, is the half-value width, that is =0.5, at value.

[0112] When a jet ejected from a nozzle enters an infinite space composed of a fluid with the same properties as itself, it is called a submerged free jet. The time-dependent changes in scour depth and width under each operating condition are essentially the same: the scour crater first rapidly deepens and widens, then develops slowly in both depth and width, and finally stabilizes.

[0113] That is, there are three stages: rapid growth stage, slow growth stage and stable stage.

[0114] like Figures 7 to 22As shown in the figure, the simulation results of six nozzle structures using hydraulic jets and air jets show that: 1. The effect of hydraulic jet is better than that of air jet. The same nozzle, different jet media will produce different spray effects. The effect of hydraulic jet is better than that of air jet. The reason may be that the air has a greater divergence in the water, which loses a lot of energy, resulting in less force actually acting on the sediment surface.

[0115] 2. The effect of hydraulic jet is better than that of air jet. Comparing the nozzle structure, it is found that the larger the target distance, the greater the divergence and the worse the jet effect.

[0116] 3. The higher the pressure, the better the jetting effect. Under the same conditions, A-1 > A-2, B-2 > B-1, and C-1 > C-2. The optimal nozzle structure is A-1, B-2, and C-1. Comparing the three nozzles, B-2 > C-1 > A-1, so the optimal nozzle is B-2, i.e., a nozzle with a 45° cone angle and a diameter of 20m is optimal.

[0117] 4. For inclined jets, at a target distance (submerged water depth) of 20 cm, the jetting effect when the nozzle is at a 45° angle to the horizontal plane is better than when the nozzle is at a 30° angle to the horizontal plane. The jet effect when the working medium is water is better than the jet effect when the working medium is air.

[0118] 5. The cross-sectional profiles of the craters reveal geometric similarities in their morphology. The depth of the craters can be divided into a rapid increase phase, a slow increase phase, and a stable phase over the course of the jet flow. Under the two medium operating conditions, the jet target distance significantly impacts air jets more than water jets, further demonstrating the greater divergence of air jets. During the air jet process, some craters exhibit a W-shaped profile. This may be due to the insufficient impact of the air force on the sediment surface, resulting in disturbances in the water. This is a manifestation of sediment movement under the influence of the water and air two-phase flow.

[0119] 6. From Figure 7 It can be seen that when the inlet pressure is 1MPa, the maximum outlet velocity of the A-1 nozzle is 43.1m / s, the maximum outlet velocity of the A-2 nozzle is 42.5m / s, the maximum outlet velocity of the B-1 nozzle is 42.8m / s, the maximum outlet velocity of the B-2 nozzle is 43.3m / s, the maximum outlet velocity of the C-1 nozzle is 43.1m / s, and the maximum outlet velocity of the C-2 nozzle is 42.9m / s.

[0120] When the inlet pressure is 1.5 MPa, the maximum outlet velocity of the A-1 nozzle is 43.1 m / s, the maximum outlet velocity of the A-2 nozzle is 42.5 m / s, the maximum outlet velocity of the B-1 nozzle is 42.8 m / s, the maximum outlet velocity of the B-2 nozzle is 43.3 m / s, the maximum outlet velocity of the C-1 nozzle is 43.1 m / s, and the maximum outlet velocity of the C-2 nozzle is 42.9 m / s.

[0121] It should also be noted that Figures 7 to 22 The English word "Vmax" shown below the accompanying figure refers to the maximum velocity out of the nozzle outlet.

[0122] like Figure 24 and Figure 25 As shown in Figure 1, soil failure models in jetting can be divided into two main categories: one is failure due to jet flow pressure, which is determined based on bearing capacity theory in soil mechanics; the other is failure due to boundary layer shear stress, which is determined based on clay erosion theory. After the jet is ejected from the nozzle, the pressure energy is converted into kinetic energy, and static pressure is no longer present.

[0123] When the working medium was air and the nozzle inlet pressure was 1 MPa, a W-shaped pit appeared in the right-angle nozzle A-2. This may be due to the severe attenuation of the air pressure in the water, resulting in a significantly reduced jet-breaking force on the sand bed compared to the outlet pressure. The right-angle nozzle exhibited greater instability compared to the conical and funnel types. This may be due to the resistance to the air jet created by its right-angle structure, which reduced the velocity at the jet's edges. This phenomenon increased with increasing diameter ratio, making it difficult to maintain the original initial velocity.

[0124] Water jets and air jets exhibit highly similar crater morphologies. Water jets are significantly more stable than air jets, and their axial energy decay is significantly lower. This is reflected in the fact that, at the same outlet pressure, the scouring depth of water jets is significantly greater than that of air jets, and this difference increases with increasing pressure. The crater morphology of water jets exhibits a similar smooth curve. However, nozzles with different structures exhibit significant differences in the crater morphology of air jets, particularly right-angle nozzles, which exhibit a central ridge. This may be due to the vortex formed by the jet scouring reaching the free surface, causing significant fluctuations in the water surface and entraining some air, increasing the jet's energy consumption and resulting in a unique morphology. Comparing nozzle structures under the two operating conditions, it was found that as the target distance increases, the greater the divergence of the jet axis, the worse the scouring effect. Higher nozzle outlet pressure leads to better scouring effect.

[0125] It should be noted that other working conditions can also be set, such as Figures 45 to 48 As shown, like Figure 45 The working conditions shown are: double nozzles and the jet medium is water, the jet velocity is 30m / s, when time t=0.01s, the particles begin to move under the action of the jet, and the particles are lifted up by the impact force. As time goes by, the depth of the disturbed particle bed gradually increases, forming a pit. The particle velocities at different depths are different, indicating that the axial velocity attenuation of the jet is affected by wall shear, turbulent characteristics and geometric conditions. Its law can be approximately described by the power law model.

[0126] like Figure 46 As shown in the figure, through the cross-sectional views of the particle states at different moments, the cross-sectional and longitudinal cross-sectional cratering effects are compared. From the comparison of the cross-sectional and longitudinal cross-sectional cratering effects, it can be seen that the impact width of the horizontally arranged nozzles is greater than the longitudinal width. This is because the two nozzles impact side by side, and the jets collide with each other to form an upward jet. In addition to the basic flow area of the single impact jet, the double impact jet also has an upper formation area and an upper jet area, and induces a vortex area between the jets and the upper jet area, resulting in a greater turbulence intensity state.

[0127] Compared with water, the attenuation rate of air is more intense, that is, under the same boundary conditions, air exhibits greater dissipation energy and water can exhibit better aggregation force.

[0128] like Figure 47 As shown in the figure, the volume fraction distribution of the water phase and the overall velocity along the central axis can be clearly divided into three stages. The first section is the potential flow core, where the maximum velocity remains constant; the second section is the characteristic attenuation zone; and the third section is the radial attenuation zone, where the velocity decay is axisymmetric. The velocity vector advances along the axis and, upon impacting the wall, vortices form on both sides, with the two sides exhibiting opposite flow directions before finally flowing out of the outlet.

[0129] like Figure 48As shown in the figure, the velocity streamlines reveal that the turbulent motion of the water is significantly higher than that of the air, with distinct vortex rings and spiral vortices. The development and dissolution of these vortex rings are closely related to the entrainment and expansion of the jet. As the vortices move downward with the flow, they merge, entraining the surrounding fluid into the jet. After the vortices merge, the jet cross-section expands. The top view of the streamlines reveals that the vortex density of the water jet is significantly greater than that of the air jet. This phenomenon may be due to the higher density of water, which imparts greater momentum and resists attenuation to some extent. On the other hand, the air jet, due to its lower density, has lower momentum even at the same initial velocity, making it more susceptible to being hindered and decelerated by the surrounding water. Air jets in water may form bubble plumes, whose behavior differs from that of continuous jets. The presence of bubbles alters the flow structure, increasing the interfacial area and thereby enhancing momentum exchange with the surrounding water. Furthermore, the upward motion of the bubbles, due to buoyancy, may cause the jet to change direction, further affecting the attenuation of the axial velocity. The rise and collapse of bubbles intensify turbulence intensity and promote energy dissipation. At the same time, the density difference between bubbles and water causes local pressure gradients, accelerating momentum loss and decay.

[0130] S1200. Based on multiple sets of solution results, orthogonal analysis is performed on multiple nozzle models to obtain an optimal parameter combination.

[0131] Alternatively, simulation calculations can be performed on combinations of multiple nozzle models, with each combination forming an experimental element. For example, the same type of nozzle models can be combined in quantity, the same type of nozzle models can be combined in angle, different types of nozzle models can be combined in quantity, different types of nozzle models can be combined in angle, etc., and different combinations can be simulated and analyzed by setting different operating parameters.

[0132] For example, the first experimental element: under the conditions of a jet target distance of 10 cm and a nozzle inlet pressure of 1 MPa, the A-1 type double nozzles are combined with intersection angles of 15°, 30° or 45°, the B-2 type double nozzles are combined with intersection angles of 15°, 30° or 45°, or the C-1 type double nozzles are combined with intersection angles of 15°, 30° or 45°.

[0133] like Figure 26As shown, the distribution of the jet impingement under an inclined jet differs from that under a vertical jet. The stagnation point of the inclined jet is offset to a certain extent, located to the side of the flow zone behind the central axis of the jet. As the impact angle decreases, the stagnation point shifts more. At this point, the jet velocity, wall static pressure, and jet thickness exhibit a non-axisymmetric distribution throughout the flow field. The jet velocity in the interaction zone increases with increasing jet pressure, while the wall static pressure varies linearly with the jet pressure. The width of the pit produced by the dual nozzles increases with increasing intersection. However, when the intersection reaches 45 degrees, a central ridge appears. When the nozzle outlet is 10 cm from the sand bed surface and the inlet pressure is 1 MPa, the right-angled dual nozzles can create a pit with a depth of 1.1 m and a width of 2 m, with a maximum nozzle velocity of 108 m / s. At an inlet pressure of 1.5 MPa, the pit can reach a depth of 1.6 m, a width of 2.5 m, and a maximum nozzle velocity of 133 m / s. When the nozzle outlet is 10 cm away from the sand bed surface and the inlet pressure is 1 MPa, the funnel-shaped double nozzle can scour the pit up to 1.5 m deep, the scouring width is 2.5 m, and the maximum nozzle speed can reach 115 m / s. When the inlet pressure is 1.5 MPa, the scouring depth can reach 1.9 m, the scouring width is greater than 2.5 m, and the maximum nozzle speed can reach 140 m / s.

[0134] For example, the second experimental element: under the conditions of a jet target distance of 10 cm and a nozzle inlet pressure of 1 MPa, the A-1 type double nozzles are combined with intersection angles of 15°, 30° or 45°, the B-2 type double nozzles are combined with intersection angles of 15°, 30° or 45°, or the C-1 type double nozzles are combined with intersection angles of 15°, 30° or 45°.

[0135] like Figure 27 As shown in the figure, compared with the parameters under the first experimental element, the parameter mutation of the second experimental element has a significantly enhanced effect, which is nearly 3 times stronger; the effect is good at an angle of 30°, and the effect is more divergent at 45°.

[0136] The third experimental element: Under the conditions of jet target distance of 10cm and nozzle inlet pressure of 1.5Mpa, the A-1 type double nozzles are combined with intersections of 15°, 30° or 45°, the B-2 type double nozzles are combined with intersections of 15°, 30° or 45°, or the C-1 type double nozzles are combined with intersections of 15°, 30° or 45°.

[0137] Compared with the parameters under the second experimental element, the parameters of the third experimental element suddenly changed, and the effect was significantly enhanced. The 30° angle had a good effect, while the 45° angle was more divergent.

[0138] The fourth experimental element: the nozzle inlet pressure is 1Mpa to 1.5Mpa, the incident angle is 15°, a double nozzle combination is used, and there are four pairs of double nozzle combinations arranged in a circular ring, and the target distance is 100cm.

[0139] like Figure 28 and Figure 29 As shown in the figure, the overall sudden enhancement is obvious. The jetting depth increases significantly from 1000mm to 1200mm, which is still insufficient to cover the entire annular cylinder section. After changing from 600mm to 800mm, the jetting effect is obviously attenuated.

[0140] The fifth experimental element: the nozzle inlet pressure is 1Mpa, the target distance is 100cm to 300cm, the incident angle is 15°, and a double nozzle combination is used with four pairs of double nozzle combinations arranged in a circular ring. Figure 30 and Figure 31 As shown in the figure, the change of target distance has little effect on the overall jet characteristics and scouring effect.

[0141] The sixth experimental element: the nozzle inlet pressure is 1.5Mpa, the target distance is 100cm, the incident angle is 15° to 22.5°, and a double nozzle combination is used with four pairs of double nozzle combinations arranged in a circular ring. Figure 32 and Figure 33 As shown in the figure, under this experimental factor, the coverage of the jet is significantly increased.

[0142] The seventh experimental element: the nozzle inlet pressure is 1Mpa to 1.5Mpa, the incident angle is 15°, the target distance is 100cm, three nozzles are arranged crosswise, and there are four pairs of three nozzles arranged in a circular ring. Figure 34 and Figure 35 As shown in the figure, the depth of the jet increases to 1600 mm. When the depth of the jet decreases from 600 mm to 800 mm, the scouring effect of the jet attenuates, and the scouring effect of the jet covers a wider range.

[0143] The eighth experimental element: the nozzle inlet pressure is 1Mpa, the incident angle is 15°, the target distance is 100cm to 300cm, three nozzles are arranged in a cross pattern, and there are four pairs of three nozzles arranged in a circular ring. Figure 36 and Figure 37 As shown in the figure, the change of target distance has little effect on the overall jet characteristics and scouring effect.

[0144] Ninth experimental element: The nozzle inlet pressure is 1Mpa, the target distance is 300cm, the incident angle is 15° to 22.5°, three nozzles are arranged in a cross pattern, and there are four pairs of three nozzles arranged in a circular ring. Figure 38 and Figure 39 As shown in the figure, under this experimental factor, the angle has a significant impact, and 22.5° has an obvious advantage, with a wider jet coverage range and a depth increase of 1200-1800mm.

[0145] The tenth experimental element: The nozzle inlet pressure is 1Mpa, the target distance is 100cm, and three nozzles are used with a 5° deflection relative to each other based on the axis. The combination of the three nozzles can rotate to form a rotating jet. By comparing the effects of rotating jet and fixed-point jet, the flushing effects of different jet characteristics are observed. Figures 40 to 42 As shown, compared to fixed-point jets, rotating jets take half the time to reach the same pit depth, have smoother pit shapes, and exhibit less backflow, whereas fixed-point jets exhibit some backflow. The velocity distribution of rotating jets exhibits significant three-dimensional characteristics: The axial velocity decays faster than that of ordinary jets, dominated by the swirl number. At low curl, the cross-sectional shape is Gaussian. As curl increases, the maximum velocity begins to deviate from the jet axis, resulting in backflow and a saddle-shaped velocity distribution. The circumferential velocity distribution pattern is determined by the swirl intensity (free vortex or rigid body rotation). With weak rotation, the circumferential velocity component is small, and the jet may resemble an ordinary jet. With strong rotation, the vortex core may break, and the velocity distribution becomes more complex. The radial velocity is driven by centrifugal force, affecting jet diffusion.

[0146] Comprehensive analysis of the ten experimental factors shows that: 1. Nozzle structure, spray angle and pressure have significant effects, while target distance has no significant effect, but the pressure drop is significant (significant below 0.5MPa); 2. The effect of the spraying angle of 45° is better than that of the spraying angle of 30°; during the spraying process, the sprayed mud and sand overflow backward and accumulate behind the nozzle, which is not conducive to mud discharge, and the 30° angle is more significant.

[0147] 3. The multi-nozzle spraying effect suddenly changes and is significantly enhanced, mainly due to the substantial increase in flow rate; 4. The jet pressure and angle are significant; the target distance and angle are not obvious, and the jet angle has a significant impact on the jet coverage; 5. Compared with fixed-point jetting, the time it takes for rotary jetting to reach the same pit depth is half that of fixed-point jetting.

[0148] In some embodiments, the optimal parameter combination is used for verification on a test device, and the sampling result of the test device is compared with the solution result. If the comparison error is within a first preset condition, the optimal parameter combination is output.

[0149] For example, the first preset condition may be that the comparison error between the sampling results of the experimental equipment and the solution results is less than or equal to 5%. It should be noted that when the comparison error between the sampling results of the experimental equipment and the solution results is greater than 5%, it proves that the error of the solution result is large and the simulation parameters need to be adjusted.

[0150] In some embodiments, the gas-liquid jet analysis method further includes regulating the pressure of the gas jet module in the test equipment, wherein the regulating pressure includes: S1300, filtering, drying and compressing the gas to form compressed gas, which is stored in a gas storage tank for use by the gas jet module.

[0151] For example, a pre-filter is used to filter the gas to remove oil and dust from the gas, a dryer is used to dry the gas to remove moisture from the gas, and a post-filter is used to further filter the oil and dust from the gas to obtain gas of qualified quality, which is then stored in a gas tank for standby use.

[0152] S1400, set the target gas pressure value, collect the real-time gas pressure value at the outlet of the first electric valve and the second electric valve in real time, compare the real-time gas pressure value with the target gas pressure value, and determine whether the comparison result meets the second preset condition. If not, adjust the opening of the first electric valve and / or the second electric valve.

[0153] It should be noted that after the gas jet is turned on, the compressed gas is discharged through the gas tank, and the real-time gas pressure values at the outlets of the first electric valve and the second electric valve are collected in real time, and the real-time gas pressure values are compared with the set target gas pressure values. When the second preset condition is not met, the opening of the first electric valve and / or the second electric valve is controlled to gradually meet the second preset condition.

[0154] The compressed air is then regulated for the first time through the first electric valve to obtain the approximate value of the required gas pressure, and then precisely regulated through the second electric valve to obtain the gas pressure value required for the test with higher accuracy. The idea is to approximate iteratively, first taking a rough approximation, and then repeatedly correcting this initial value until the predetermined accuracy requirement is reached.

[0155] The control system of the embodiment of the present invention uses an explosion-proof pressure transmitter, which is composed of an integrated intelligent sensor and peripheral circuits. The sensor part consists of a pressure sensor, a signal modulation circuit, a dedicated digital processing chip, a temperature sensor, and a data storage device, while the peripheral electronic circuit part consists of a display screen, function keys, and a circuit system. The gas pressure signal is converted into an electrical signal by the pressure sensor. After modulation, the electrical signal is sent to a dedicated digital processing chip for data processing, and then converted into a 4-20mA current output corresponding to the pressure signal. A digital signal is superimposed on the current signal for communication and transmitted to the PLC. Gas pressure transmitter parameters: Measuring range: -0.1-20Mpa: Housing protection grade: IP65; Accuracy grade: 0.2; Output signal: 4-20mA (two-wire system). 0-10VDC, 0.5VDC. 1-5VDC (three-wire system); Explosion-proof pressure transmitter power supply voltage: 24VDC; Medium contact material: 316 stainless steel: Housing material: 304 or 316 stainless steel; Installation method: Threaded installation; Pressure interface: M20x1.5, M12x1. G1 / 4, 1 / 2 male thread, etc.; Wiring method: four-core shielded cable.

[0156] By comparing the measured downstream pressure with the target value and applying PI regulation, the control system issues a command to the valve controller, which then transmits it to the actuator. The target value is set. The compressed air is initially regulated by the first electric valve, obtaining an approximate value for the required gas pressure. This is then fine-tuned by the second electric valve. The specific operation is as follows: when the upstream pressure decreases, the second electric valve automatically opens wider. If the second electric valve reaches 100% and still does not meet the pressure requirement, the first electric valve opens again, and this process continues until the required pressure is met. This allows for a more precise gas pressure value to be obtained. The concept is to achieve a successive approximation through iterative calculations, first obtaining a rough approximation and then repeatedly correcting this initial value until the desired accuracy is achieved. After the control program runs, a comparison of the upstream and downstream pressures of the pressure regulating valve reveals relatively stable downstream pressure. These parameters are then adjusted using self-tuning methods to achieve system stability, rapid response, and oscillation suppression.

[0157] The air jet experiment module is based on pressure control for pneumatic injection and detection, utilizing variable frequency measurement and control for data acquisition and related data processing. The primary goal is to address the lack of process parameters for coupled medium- and low-pressure gas, liquid, and solid multiphase flows. By leveraging the medium- and low-pressure air jet experimental platform, appropriate evaluation indicators for recovery processes under air jet conditions will be developed. A comprehensive medium- and low-pressure air jet experimental device will be constructed to conduct air jet flushing tests. This requires the ability to test various parameters, such as speed, flow rate, and pressure, and to collect, process, and analyze key experimental data.

[0158] The main content covers three parts: cavitating water jet flushing system design, numerical simulation of the cavitating water jet flow field, and experimental verification of the cavitating flushing effect. In the cavitating water jet system, the various components of the cavitating water jet system are designed and selected based on relevant parameters. The model, pump pressure, flow rate, and power of the high-pressure device in the cavitating water jet system are determined. The matching high-pressure water / air supply pipeline is designed. The type, material, and size of the water / air valve and pressure regulating valve in the high-pressure pipeline are selected. The type, range, and accuracy of the flow meter and pressure gauge are selected, and a test bench suitable for submerged jet is designed. The foundation for achieving all these test requirements is an air jet pressure stabilization and detection controller based on automated control.

[0159] The entire system consists of a control system, a pressure-stabilizing valve group, and pressure detection elements. The auxiliary module structure mainly consists of equipment cabinets, support mechanisms, safety protection, and signage. The equipment cabinets are all made of aluminum alloy profiles. The process flow is drawn on the panel and the control valves are installed, making the overall operation clear and reliable.

[0160] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A gas-liquid jet analysis method, characterized in that: The steps include: Construct nozzle, jet medium and soil models; Meshing the nozzle, jet medium and soil models to obtain finite element mesh models of the nozzle, jet medium and soil; Perform particle filling based on the finite element mesh model of soil to form a discretized soil particle model; A coupled model is formed by combining the finite element mesh model of the nozzle and jet medium with the discretized soil particle model; Set the material parameters, governing equations, fluid unit velocity, pressure, and pressure gradient of the coupled model; Synchronously set the boundary conditions, time step, first convergence condition and second convergence condition of the coupling model, read the mesh nodes, unit information, velocity, density of the soil particle model and calculate the unit porosity; Update the fluid velocity field of the jet medium in the coupled model, and update the velocity and position of the soil particles; Setting a finite element-discrete element coupling solver, performing a finite element solution on the coupling model, determining whether the finite element solution result satisfies a first convergence condition, and if so, importing the finite element solution result into the coupling solver, solving for the resultant force and moment acting on the soil particles, and determining whether a discrete element cycle is completed. If so, importing the discrete element solution result into the coupling solver; The coupled model is solved by coupled simulation calculation to determine whether the solution meets the second convergence condition. If so, the solution is output.

2. The gas-liquid jet analysis method according to claim 1, characterized in that: The particle filling based on the soil finite element grid model to form a discretized soil particle model includes: Setting a first contact model between soil particles and a second contact model between soil particles and soil particle model boundaries; Set the particle filling parameters.

3. The gas-liquid jet analysis method according to claim 2, characterized in that: The control equations include a continuity equation and a momentum equation, and the momentum equations include a gas phase momentum equation, a liquid phase momentum equation, a solid phase momentum equation, and a solid phase particle kinematic equation.

4. The gas-liquid jet analysis method according to claim 3, characterized in that: The control equation further includes a particle drag model, which is a Gidaspow drag model.

5. The gas-liquid jet analysis method according to any one of claims 1 to 4, characterized in that: The material parameters are the density of the liquid medium 998kg / m 3 , the viscosity of the liquid medium is 0.001003kg·m -1 ·s -2 , the density of the gas medium is 1.225kg / m 3 , the viscosity of the gas medium is 1.8×10 -5 kg·m -1 ·s -2 , soil density 2500kg / m 3 , soil viscosity 10kg·m -1 ·s -2 .

6. The gas-liquid jet analysis method according to any one of claims 1 to 4, characterized in that: The boundary conditions, time step and second convergence condition of the coupling model are set as follows: The nozzle inlet boundary is set to pressure inlet with an inlet pressure of 1 MPa to 1.5 MPa, and the nozzle outlet boundary condition is set to pressure outlet with a pressure value of 101325 Pa; Set the wall boundary of the soil model to a no-slip fixed wall, all velocities to 0, and the interface between the jet medium and the soil to a penetrating interface; The time step is set to 1×10 -5 s, the first and second convergence conditions are that the residual is less than or equal to 1×10 -4 .

7. The gas-liquid jet analysis method according to claim 6, characterized in that: The coupling simulation calculation and solution of the coupling model includes: Setting a solution model, wherein the solution model is an Euler multiphase flow turbulence model and a VOF model; Set the solver type, which is a coupled implicit solver; Set a solution algorithm, which is a Coupled algorithm based on pressure-velocity coupling. Set a relaxation coefficient in the Coupled algorithm, and set the discrete format of pressure in the solution algorithm to standard mode, and the discrete format of momentum, turbulent kinetic energy, and turbulent dissipation rate to first-order upwind.

8. The gas-liquid jet analysis method according to claim 1, characterized in that: The following steps are also included: Constructing multiple types of nozzle models, wherein the shapes and size parameters of the outlets of the multiple nozzle models are different, and corresponding the multiple nozzle models with the parameters and ranges of the nozzles to form multiple nozzle models to be analyzed; Performing coupled simulation calculations on the plurality of nozzle models to be analyzed independently or in combination to obtain a plurality of sets of solution results; Based on multiple sets of solution results, orthogonal analysis is performed on various nozzle models to obtain the optimal parameter combination.

9. The gas-liquid jet analysis method according to claim 8, characterized in that: The optimal parameter combination is used for verification on a test device, and a sampling result of the test device is compared with the solution result. If the comparison error is within a first preset condition, the optimal parameter combination is output.

10. The gas-liquid jet analysis method according to claim 9, characterized in that: The test device further includes performing voltage stabilization and regulation on the air jet module in the test device, wherein the voltage stabilization and regulation includes: Filter, dry and compress the gas to form compressed gas which is stored in the gas storage tank for use by the gas jet module; Set a target gas pressure value, collect real-time gas pressure values at the outlets of the first electric valve and the second electric valve in real time, compare the real-time gas pressure value with the target gas pressure value, and determine whether the comparison result meets the second preset condition. If not, adjust the opening of the first electric valve and / or the second electric valve.

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