Geological burying seepage acceleration testing machine based on magnetic suspension centrifugal technology and testing method

Abstract

The invention discloses a geological burying seepage acceleration testing machine based on a magnetic suspension centrifugal technology. The geological burying seepage acceleration testing machine comprises a fixed base; the rotary driving mechanism comprises a shaft rotor rotationally arranged on the fixed base, at least two magnetic bearings used for supporting the shaft rotor and a synchronous motor used for driving the shaft rotor to rotate, and the shaft rotor is perpendicular to the fixed base; the rotating connecting rod is fixedly connected with the upper end of the shaft rotor, and the rotating connecting rod is perpendicular to the shaft rotor; the two centrifugal storage boxes are movably connected with the ends of the rotating connecting rods in a one-to-one correspondence mode, and the centrifugal storage boxes can rotate to the state that the axes are parallel to the rotating connecting rods in the process that the rotating connecting rods rotate along with the shaft rotor; and the two multi-field coupling test boxes are coaxially arranged in the centrifugal storage box in a one-to-one correspondence manner and are used for accommodating test cores and constructing a multi-field coupling test environment. Based on the centrifugal acceleration technology and the magnetic bearing technology, more extreme underground environments can be simulated, the test time is effectively shortened, and the test efficiency is improved.

Description

Technical Field

[0001] The invention relates to the fields of fluid mechanics and geotechnical engineering, and in particular to a geological storage seepage acceleration testing machine and a testing method based on magnetic suspension centrifugal technology. Background Art

[0002] In the research of geological engineering, geotechnical engineering and environmental science, it is very important to accurately evaluate the seepage performance of materials such as soil and rock. The core fluid-solid coupling seepage experiment is an important means to evaluate the deformation and seepage performance of rocks under the action of fluid. However, traditional seepage experiments often rely on ordinary triaxial loading equipment to simulate the underground environment by applying uniform surface stress to the sample. Although this method is simple and effective, it cannot fully simulate the complex body stress state in the actual underground environment. In the process of injecting fluid into deep formations, the fluid-solid coupling phenomenon is significant. The injection and flow of fluid will not only affect the rock surface, but more importantly, it will change the stress distribution and changes in multiple regions inside the formation rock. This rock deformation and stress redistribution caused by fluid is three-dimensional and volumetric, and together with the gravity of the reservoir itself, it forms a complex body stress bearing system. Therefore, the traditional triaxial loading equipment that simulates the underground environment by applying surface stress has limitations in simulating the actual formation stress distribution, and there may be certain errors in the study of seepage behavior of deep soil or rock.

[0003] In addition, since small-scale core sealing loading experiments are highly dependent on the long interaction process of multi-physical field coupling, the dynamic equilibrium process of the entire experiment cannot be controlled by human intervention, especially in the simulation of the thermal-fluid-mechanical-chemical multi-field coupling process, which requires a very long time. For example, when a 50mm×100mm cylindrical coal core subjected to axial pressure and confining pressure of 6MPa is continuously injected with CO2 gas at a gas pressure of 3MPa, the time required for the change of the permeability of the coal sample from the initial state to the final equilibrium stable state is close to 100 days. Since the size and stress environment of deep low-permeability reservoirs are much larger than those of laboratory samples, the deformation or seepage equilibrium time of geological reservoirs will exceed several years or decades, and the re-stabilization of the entire engineering disturbance has become a key factor in measuring the long-term economic reliability of the engineering. Similarly, energy projects such as deep reservoir carbon dioxide geological storage displacement, formation nuclear waste leakage, trace chemical migration, drilling grouting plugging, sand-carrying proppant migration and unconventional gas reservoir production all require physical simulation samples with reduced time and space scales.

[0004] In summary, in the prior art, when traditional triaxial loading equipment is used to test the core by applying surface stress to simulate the underground environment, it takes a long time and has low overall test efficiency. It is only suitable for gas reservoir exploitation tests under conventional geological conditions and cannot be used for closed tests of geological buried fluids (hydrogen storage, carbon dioxide storage and air compression energy storage). Summary of the invention

[0005] In order to address the deficiencies in the prior art, the present invention provides a geological storage seepage acceleration testing machine and a testing method based on magnetic levitation centrifugal technology. Based on centrifugal acceleration technology and magnetic bearing technology, it can simulate more extreme underground environments, and effectively shorten the test time and improve the test efficiency.

[0006] In order to achieve the above object, the specific scheme adopted by the present invention is:

[0007] A geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology, comprising:

[0008] Fixed base;

[0009] A rotary drive mechanism, comprising a shaft rotor rotatably arranged on the fixed base, at least two magnetic bearings for supporting the shaft rotor, and a synchronous motor for driving the shaft rotor to rotate, wherein the shaft rotor is perpendicular to the fixed base;

[0010] A rotating connecting rod is fixedly connected to the upper end of the shaft rotor, and the rotating connecting rod and the shaft rotor are perpendicular to each other;

[0011] Two centrifugal storage boxes are movably connected to the ends of the rotating connecting rod in a one-to-one correspondence, and the centrifugal storage boxes can be rotated to a state where the axis is parallel to the rotating connecting rod during the rotation of the rotating connecting rod along with the shaft rotor;

[0012] Two multi-field coupling test boxes are coaxially arranged in the centrifugal storage box in a one-to-one correspondence, and are used to accommodate test cores and construct a multi-field coupling test environment.

[0013] Preferably, the rotary drive mechanism further comprises a thrust bearing fixedly arranged on the fixed base, and the thrust bearing and the magnetic bearing jointly support the shaft rotor;

[0014] Two magnetic bearings are provided, and a distance is left between the two magnetic bearings. The synchronous motor is arranged between the two magnetic bearings.

[0015] Preferably, the magnetic bearing includes a coil assembly, which includes two bottom electromagnetic coils and a plurality of side electromagnetic coils, the two bottom electromagnetic coils and all the side electromagnetic coils are evenly distributed along the circumferential direction of the shaft rotor, and the two bottom electromagnetic coils are symmetrically arranged about the axis of the shaft rotor, and the bottom electromagnetic coil and the side electromagnetic coil cooperate to generate a driving magnetic field that can drive the shaft rotor to rotate.

[0016] Preferably, the multi-field coupling test box includes a test box body, in which an axial compressive stress axis and a load-bearing axis are relatively arranged, wherein the axial compressive stress axis is slidably arranged, and the load-bearing axis is fixedly arranged, and an axial compression test space for accommodating the test core is formed between the axial compressive stress axis and the load-bearing axis, and when the centrifugal storage box is rotated to a state where the axis is parallel to the rotating connecting rod, the axial compressive stress axis is close to the rotating connecting rod, and the load-bearing axis is away from the rotating connecting rod.

[0017] Preferably, an axial stress control pin with adjustable position is provided in the test box, and the axial stress control pin is used to limit the sliding range of the axial compressive stress axis.

[0018] Preferably, a confining pressure chamber is provided in the test box, the test core is located in the confining pressure chamber, a fluid inlet pipe valve and a fluid outlet pipe valve are provided in the confining pressure chamber, a plurality of local strain gauges are provided on the surface of the test core, and at least one radial chain strain gauge is sleeved on the test core.

[0019] Preferably, the fluid inlet pipe valve and the fluid outlet pipe valve are commonly connected to a fluid reservoir for storing fluid, and at least one compression impeller is fixedly sleeved on the shaft rotor, and the compression impeller can pump the fluid in the fluid reservoir into the confining pressure chamber through the fluid inlet pipe valve as the shaft rotor rotates.

[0020] Preferably, an axial displacement extensometer is provided in the test box, and the axial displacement extensometer is located on the side of the test core. Both sensing ends of the axial displacement extensometer are fixedly connected to the test core, and the two sensing ends are distributed along the length direction of the test core.

[0021] Preferably, the centrifugal storage box is movably connected to the end of the rotating connecting rod through a pull rope.

[0022] A geological burial seepage acceleration test method based on magnetic levitation centrifugal technology, based on the above-mentioned geological burial seepage acceleration test machine based on magnetic levitation centrifugal technology, the method comprises the following steps:

[0023] Placing the test core into the multi-field coupling test box, and placing the multi-field coupling test box into the centrifugal storage box;

[0024] Connecting the centrifugal storage box to the rotating connecting rod;

[0025] The rotary drive mechanism is used to drive the rotating connecting rod to rotate, and the rotating connecting rod drives the centrifugal storage box and the multi-field coupling test box to rotate synchronously.

[0026] Beneficial effects:

[0027] 1. The present invention adopts centrifugal acceleration technology, and can more accurately reproduce extreme conditions such as high pressure, high temperature and rapid flow in deep geological bodies through supergravity environment simulation, which is more in line with the actual underground environment and can fully simulate the seepage and deformation behavior of deep rocks. For test scenarios such as geological burial of nuclear waste, carbon dioxide carbon sequestration, and fluid-solid coupling processes of harmful trace elements for decades or even hundreds of years, the present invention can fully simulate the seepage conditions and the evolution of rock structure properties in these processes. Based on the test results and the actual geological data of a specific area, the catastrophic phenomena such as leakage of harmful substances, rock destruction and collapse can be predicted, which can provide guidance for practical projects such as geological exploration and mineral mining;

[0028] 2. The present invention adopts magnetic bearing technology to realize centrifugal acceleration of the multi-field coupling test box. The shaft rotor used to drive the multi-field coupling test box to rotate is in a non-contact suspension state and will not be directly affected by the friction of the supporting bearing. It has a larger speed adjustment range and can simulate more underground environments.

[0029] 3. The present invention has high integration, small footprint and lower testing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of the overall structure of the testing machine of the present invention;

[0032] Figure 2 It is a structural diagram of a multi-field coupling test chamber;

[0033] Figure 3 is a structural schematic diagram of a rotary drive mechanism;

[0034] Figure 4 is a schematic diagram of the structure of a magnetic bearing;

[0035] Figure 5 It is a schematic diagram of the driving principle of the magnetic bearing;

[0036] Figure 6 It is a schematic diagram of the control circuit of each electromagnetic coil in the magnetic bearing;

[0037] Figure 7 It is a schematic diagram of the state of the testing machine of the present invention before the test starts;

[0038] Figure 8 It is a schematic diagram of the state of the testing machine of the present invention during the testing process.

[0039] Figure markings: 1-fixed base, 2-rotation drive mechanism, 3-rotating connecting rod, 4-centrifugal storage box, 5-test box, 6-axial compressive stress axis, 7-local strain gauge, 8-bearing axis, 9-test core, 10-heating assembly, 11-axial stress control pin, 12-radial chain strain gauge, 13-axial displacement extensometer, 14-sealed membrane, 15-gasket, 16-fluid outlet pipe valve, 17-fluid inlet pipe valve, 18-confining pressure chamber, 19-compression impeller, 20-first bearing, 21-position sensor, 22-coil assembly, 23-synchronous motor, 24-second bearing, 25-thrust bearing, 26-axis rotor, 27-rotor limit buckle, 28-side electromagnetic coil, 29-bottom electromagnetic coil, 30-stator yoke, 31-rotor yoke. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figures 1 to 3 As shown, a geological burial seepage acceleration testing machine based on magnetic levitation centrifugal technology includes a fixed base 1, a rotary drive mechanism 2, a rotating connecting rod 3, two centrifugal storage boxes 4 and two multi-field coupling test boxes.

[0042] The fixed base 1 serves as the supporting foundation of the entire testing machine and is directly fixed in the testing site.

[0043] The rotary drive mechanism 2 includes a shaft rotor 26 rotatably disposed on a fixed base 1 , at least two magnetic bearings for supporting the shaft rotor 26 , and a synchronous motor 23 for driving the shaft rotor 26 to rotate, and the shaft rotor 26 is perpendicular to the fixed base 1 .

[0044] The rotating connecting rod 3 is fixedly connected to the upper end of the shaft rotor 26 , and the rotating connecting rod 3 and the shaft rotor 26 are perpendicular to each other.

[0045] The two centrifugal storage boxes 4 are movably connected to the ends of the rotating connecting rod 3 in a one-to-one correspondence. When the rotating connecting rod 3 rotates with the shaft rotor 26, the centrifugal storage boxes 4 can rotate to a state where the axis is parallel to the rotating connecting rod 3.

[0046] Two multi-field coupling test boxes are coaxially arranged in the centrifugal storage box 4 in a one-to-one correspondence, and are used to accommodate the test cores 9 and construct a multi-field coupling test environment.

[0047] The rotary drive mechanism 2 further includes a thrust bearing 25 fixedly disposed on the fixed base 1 , and the thrust bearing 25 and the magnetic bearing jointly support the shaft rotor 26 .

[0048] like Figure 7 and 8 As shown, when conducting the test, the test core 9 is first placed in the multi-field coupling test box, and a multi-field coupling test environment is constructed in the multi-field coupling test box, and the multi-field coupling test environment can apply axial pressure, confining pressure, heat and seepage gas to the test core 9; then, the two centrifugal storage boxes 4 are correspondingly hung at the two ends of the rotating connecting rod 3, and the two multi-field coupling test boxes are correspondingly placed in the centrifugal storage box 4. At this time, the centrifugal storage box 4 and the internal multi-field coupling test box are in a suspended state under the action of gravity; then, the rotary drive mechanism 2 is started, and the shaft rotor 26 of the rotary drive mechanism 2 rotates And it drives the rotating connecting rod 3 to rotate synchronously. During the rotation of the rotating connecting rod 3, the two centrifugal storage boxes 4 rotate to a state where the axis is parallel to the rotating connecting rod 3 under the centrifugal action. More specifically, at this time, the centrifugal storage box 4 and the rotating connecting rod 3 are coaxial, and the multi-field coupling test environment in the multi-field coupling test box will also change due to the centrifugal action; the multi-field coupling test environment, especially the axial pressure and confining pressure therein, can be changed by controlling the rotation speed of the shaft rotor 26 and the rotating connecting rod 3, thereby accelerating the test, and being able to simulate the stress state of underground environmental bodies at different depths, which can expand the scope of application of the test. In order to ensure that the centrifugal storage box 4 can smoothly rotate to a state where the axis is parallel to the rotating connecting rod 3 under the centrifugal action, the centrifugal storage box 4 is movably connected to the end of the rotating connecting rod 3 through a pull rope.

[0049] When the rotary drive mechanism 2 rotates at a certain angular velocity, the multi-field coupling test box gradually tends to a horizontal state, and the multi-field coupling test box obtains a horizontal outward centrifugal force:

[0050] F=ma=mω 2 R;

[0051] Wherein, F is the centrifugal force exerted on the multi-field coupling test box, m is the mass of the multi-field coupling test box, a is the centrifugal acceleration, ω is the angular velocity of the rotary drive mechanism 2, and R is the distance from the axis of the shaft rotor 26 in the rotary drive mechanism 2 to the center of the multi-field coupling test box.

[0052] On the other hand, during the rotation process, the multi-field coupling test chamber is also subject to self-gravity:

[0053] f = mg;

[0054] Where f is the self-weight stress of the multi-field coupling test box, and g is the gravitational acceleration.

[0055] Furthermore, the resultant force G borne by the multi-field coupling test chamber is:

[0056]

[0057] When the rotation speed of the rotary drive mechanism 2 reaches a certain level, the centrifugal force on the multi-field coupling test box is much greater than the gravity. At this time, the gravity of the multi-field coupling test box itself can be ignored. At this time, the resultant force on the multi-field coupling test box is:

[0058] G'≈ma=mω 2 R.

[0059] On the basis of the above force analysis, considering that the realization process of the multi-field coupling test chamber is to reduce the prototype according to a certain proportion, the multi-field coupling test chamber is placed in a centrifugal field for testing, and the centrifugal force is used to simulate the gravity of the prototype, thereby compensating for the loss of deadweight caused by the reduction of the multi-field coupling test chamber.

[0060] Suppose that the prototype with volume V is reduced to And placed in the centrifugal field, at this time, the centrifugal force on the multi-field coupling test box is:

[0061] F=ρVω 2 ;

[0062] In the formula, ρ represents the density of the prototype, and the self-weight stress of the prototype is:

[0063] σ=ρgV.

[0064] To make the stress state of the multi-field coupling test chamber the same as that of the prototype, F = σV, and thus the centrifugal acceleration a = ng. If the prototype is only subjected to gravity, when the size is reduced to The multi-field coupling test chamber is operated at a centrifugal acceleration of n

[0065] When the acceleration is 1.5 times the gravity, the stress distribution of the multi-field coupling test chamber is similar to that of the prototype, so it can show the deformation and failure process similar to that of the prototype.

[0066] In order to ensure the stability of the multi-field coupling test box in the centrifugal storage box 4, a caliper for fixing the multi-field coupling test box is provided in the centrifugal storage box 4. When the multi-field coupling test box is placed in the centrifugal storage box 4, the axis of the multi-field coupling test box coincides with the axis of the centrifugal storage box 4, that is, the multi-field coupling test box and the centrifugal storage box 4 are coaxially arranged, and the caliper is arranged in the gap between the multi-field coupling test box and the centrifugal storage box 4. The caliper belongs to a mature prior art and is not described here. In other embodiments of the present invention, other fixing methods may also be adopted. For example, a plurality of screw holes are provided at the end or side of the multi-field coupling test box. After the multi-field coupling test box is placed in the centrifugal storage box 4, a plurality of bolts are used to fix the multi-field coupling test box and the centrifugal storage box 4.

[0067] In order to ensure the stability of the shaft rotor 26, in the present invention, two magnetic bearings are provided, namely the first bearing 20 and the second bearing 24, and a distance is left between the two magnetic bearings, and the synchronous motor 23 is arranged between the two magnetic bearings. The two magnetic bearings can jointly support the shaft rotor 26, and the synchronous motor 23 that drives the shaft rotor 26 to rotate is arranged between the two magnetic bearings, which can avoid the end of the shaft rotor 26 from shaking, and achieve the effect of ensuring the stability of the shaft rotor 26, thereby ensuring that the rotating connecting rod 3 can rotate stably, and avoiding the centrifugal storage box 4 and the multi-field coupling test box from shaking during the rotation process. In the present invention, the synchronous motor 23 can adopt a DC synchronous motor, which belongs to conventional technology and will not be repeated here.

[0068] like Figures 4 to 6As shown, the specific structure of the magnetic bearing is as follows: the magnetic bearing includes a coil assembly 22, the coil assembly 22 includes two bottom electromagnetic coils 29 and a plurality of side electromagnetic coils 28, the two bottom electromagnetic coils 29 and all the side electromagnetic coils 28 are evenly distributed along the circumferential direction of the shaft rotor 26, and the two bottom electromagnetic coils 29 are symmetrically arranged about the axis of the shaft rotor 26, and the bottom electromagnetic coils 29 and the side electromagnetic coils 28 cooperate to generate a driving magnetic field that can drive the shaft rotor 26 to rotate. A permanent magnet that cooperates with the driving magnetic field is arranged on the shaft rotor 26. When the bottom electromagnetic coil 29 and the side electromagnetic coil 28 are energized and generate a driving magnetic field, the magnetic lines of force of the driving magnetic field in the space inside the magnetic bearing are parallel to the magnetic lines of force of the permanent magnets on the shaft rotor 26, and a repulsive effect is generated on the permanent magnets on the shaft rotor 26. Relying on the perpendicular relationship between the magnetic induction lines and the magnetic levitation lines and the parallel relationship between the magnetic induction lines and the magnetic levitation lines, the repulsive effect can be used to make the shaft rotor 26 in a suspended state without contacting the coil assembly 22. Furthermore, by controlling the bottom electromagnetic coil 29 and the side electromagnetic coil 28, the driving magnetic field can be used to drive the shaft rotor 26 to rotate, and the shaft rotor 26 is in a non-contact state, which can greatly reduce the friction on the shaft rotor 26 and expand the adjustable speed range of the shaft rotor 26, ultimately enabling the test machine of the present invention to simulate more underground environments. The thrust bearing 25 is used to prevent the shaft rotor 26 from axial displacement, ensure that the shaft rotor 26 is in a stable position, and avoid shaking the centrifugal storage box 4 and the multi-field coupling test box. A rotor limit buckle 27 can also be set at the other end of the shaft rotor 26 to further limit the shaft rotor 26 and prevent the shaft rotor 26 from moving axially.

[0069] In one embodiment of the test machine of the present invention, the coil assembly 22 includes six side electromagnetic coils 28 and two bottom electromagnetic coils 29, and is provided with four stator yokes 30. The specific arrangement of each electromagnetic coil and the stator yoke 30 is as follows: Figure 5As shown. All electromagnetic coils 28 are connected to a controller through a driver, and the controller controls the current of the electromagnetic coil through the driver to generate a driving magnetic field of different strengths. Four rotor yokes 31 are arranged on the shaft rotor 26. Four stator yokes 30 and four stator yokes 29 form four groups of closed magnetic motive forces correspondingly, which jointly excite the shaft rotor 26 to rotate. In order to further protect the rotary drive mechanism 2, a distance sensor for monitoring the distance between the shaft rotor 26 and the coil assembly 22 can also be set, or a position sensor for monitoring the position of the shaft rotor 26 can be set to measure the position of the shaft rotor 26 and transmit the measurement data to the controller. The controller compares the preset reference displacement and the measurement data of the position sensor, and then controls the operation of the driver to adjust the current of each electromagnetic coil, and finally changes the force condition of the shaft rotor 26 to ensure the force balance of the shaft rotor 26. On the other hand, when the measurement data of the position sensor or the distance sensor reflects that the shaft rotor 26 is unstable and falls, it can be stopped in time to protect the rotary drive mechanism 2 to avoid damage to the shaft rotor 26 and the coil assembly 22 due to severe collision and friction.

[0070] The specific structure of the multi-field coupling test box is as follows: the multi-field coupling test box includes a test box body 5, in which an axial compressive stress axis 6 and a bearing axis 8 are relatively arranged, wherein the axial compressive stress axis 6 is slidably arranged, and the bearing axis 8 is fixedly arranged, and an axial compressive test space for accommodating the test core 9 is formed between the axial compressive stress axis 6 and the bearing axis 8. When the centrifugal storage box 4 rotates to a state where the axis is parallel to the rotating connecting rod 3, the axial compressive stress axis 6 is close to the rotating connecting rod 3, and the bearing axis 8 is away from the rotating connecting rod 3. In the multi-field coupling test box, the axial compressive stress axis 6 is used to move toward the test core 9 and squeeze the test core 9 under the action of centrifugation during the rotation of the multi-field coupling test box, and the bearing axis 8 is used to support the test core 9, and cooperate with the axial compressive stress axis 6 to achieve the effect of applying axial pressure to the test core 9, thereby simulating the overburden stress that the test core 9 is subjected to in the underground environment. In order to limit the axial pressure that the axial compressive stress shaft 6 can apply to the test core 9, an axial stress control pin 11 with an adjustable position is provided in the test box 5. The axial stress control pin 11 is used to limit the sliding range of the axial compressive stress shaft 6. When the axial compressive stress shaft 6 contacts the axial stress control pin 11 during the sliding process, it will be restricted by the axial stress control pin 11 and cannot continue to move, thereby avoiding applying excessive axial pressure to the test core 9.

[0071] Furthermore, a confining pressure chamber 18 is provided in the test box 5, and the test core 9 is located in the confining pressure chamber 18. A fluid inlet pipe valve 17 and a fluid outlet pipe valve 16 are provided in the confining pressure chamber 18. Several local strain gauges 7 are provided on the surface of the test core 9. The local strain gauges 7 are used to monitor the deformation of the local surface of the test core 9 under the action of axial pressure and confining pressure, so as to determine the internal volume strain of the core 9. At least one radial chain strain gauge 12 is sleeved on the test core 9, and the radial chain strain gauge 12 is used to monitor the radial displacement of the test core 9. An axial displacement extensometer 13 is provided in the test box 5, and the axial displacement extensometer 13 is located on the side of the test core 9. The two sensing ends of the axial displacement extensometer 13 are fixedly connected to the test core 9, and the two sensing ends are distributed along the length direction of the test core 9. The axial displacement extensometer 13 is used to monitor the axial displacement deformation of the test core 9.

[0072] After the test core 9 is placed in the confining pressure chamber 18, a pressurized liquid is injected into the confining pressure chamber 18, and confining pressure can be applied to the test core 9 from the circumference of the test core 9 in the confining pressure chamber 18 to simulate the circumferential stress received by the test core 9 in the underground environment. The fluid inlet pipe valve 17 and the fluid outlet pipe valve 16 cooperate to control the fluid injected into the test core 9 to simulate the seepage of the test core 9.

[0073] Furthermore, the fluid inlet pipe valve 17 and the fluid outlet pipe valve 16 are connected together to a fluid storage device for storing fluid, and at least one compression impeller 19 is fixedly sleeved on the shaft rotor 26. The compression impeller 19 can pump the fluid in the fluid storage device into the confining pressure chamber 18 through the fluid inlet pipe valve 17 during the rotation of the shaft rotor 26. During the rotation of the shaft rotor 26, the compression impeller 19 rotates synchronously, which can provide power for the fluid, thereby eliminating the need for additional fluid supply power devices. On this basis, a pressure gas storage tank can also be set in the centrifugal storage box 4 to indirectly serve as a gas pressurizing device. Through this arrangement, the gas delivery pipeline can be integrated into the centrifugal storage box 4 and the multi-field coupling test box, and then rotate synchronously with the centrifugal storage box 4 and the multi-field coupling test box to ensure that the gas can be delivered stably.

[0074] A sealed film 14 can also be set on the surface of the test core 9, and gaskets 15 in contact with the sealed film 14 are set at both ends of the test core 9, and the two gaskets 15 are also in contact with the axial compressive stress axis 6 and the load-bearing axis 8 respectively. The gasket 15 can ensure that the axial pressure can be evenly loaded on the test core 9.

[0075] In order to further simulate the temperature condition of the test core 9 in the underground environment, a heating component 10 may be provided on the multi-field coupling test box, and the heating component 10 is used to heat the test core 9 .

[0076] A geological burial seepage acceleration test method based on magnetic levitation centrifugal technology, based on the above-mentioned geological burial seepage acceleration test machine based on magnetic levitation centrifugal technology, the method includes the following steps.

[0077] S1. Place the test core 9 into a multi-field coupling test box and clamp it using a conventional triaxial core holder, and place the multi-field coupling test box into a centrifugal storage box 4. In this embodiment, the test core 9 is cylindrical, with a diameter of 50 mm and a length of 100 mm.

[0078] S2, connecting the centrifugal storage box 4 to the rotating connecting rod 3. Specifically, the centrifugal storage box 4 can be suspended on the rotating connecting rod 3 by a steel rope.

[0079] S3. The rotary drive mechanism 2 is used to drive the rotating connecting rod 3 to rotate, and the rotating connecting rod 3 drives the centrifugal storage box 4 and the multi-field coupling test box to rotate synchronously.

[0080] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0081] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology, characterized in that: include: A fixed base (1); A rotary drive mechanism (2), comprising a shaft rotor (26) rotatably arranged on the fixed base (1), at least two magnetic bearings for supporting the shaft rotor (26), and a synchronous motor (23) for driving the shaft rotor (26) to rotate, wherein the shaft rotor (26) is perpendicular to the fixed base (1); A rotating connecting rod (3) is fixedly connected to the upper end of the shaft rotor (26), and the rotating connecting rod (3) and the shaft rotor (26) are perpendicular to each other; Two centrifugal storage boxes (4) are movably connected to the ends of the rotating connecting rod (3) in a one-to-one correspondence, and when the rotating connecting rod (3) rotates with the shaft rotor (26), the centrifugal storage box (4) can rotate to a state where the axis is parallel to the rotating connecting rod (3); Two multi-field coupling test boxes are coaxially arranged in the centrifugal storage box (4) in a one-to-one correspondence, and are used to accommodate test cores (9) and construct a multi-field coupling test environment.

2. A geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 1, characterized in that: The rotary drive mechanism (2) further comprises a thrust bearing (25) fixedly arranged on the fixed base (1), wherein the thrust bearing (25) and the magnetic bearing jointly support the shaft rotor (26); Two magnetic bearings are provided, and a distance is left between the two magnetic bearings; the synchronous motor (23) is arranged between the two magnetic bearings.

3. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 1, characterized in that: The magnetic bearing comprises a coil assembly (22), wherein the coil assembly (22) comprises two bottom electromagnetic coils (29) and a plurality of side electromagnetic coils (28), wherein the two bottom electromagnetic coils (29) and all the side electromagnetic coils (28) are evenly distributed along the circumferential direction of the shaft rotor (26), and the two bottom electromagnetic coils (29) are symmetrically arranged about the axis of the shaft rotor (26), and the bottom electromagnetic coils (29) and the side electromagnetic coils (28) cooperate to generate a driving magnetic field capable of driving the shaft rotor (26) to rotate.

4. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 1, characterized in that: The multi-field coupling test box comprises a test box body (5), wherein an axial compressive stress axis (6) and a bearing axis (8) are arranged relatively to each other in the test box body (5), wherein the axial compressive stress axis (6) is arranged in a sliding manner, and the bearing axis (8) is arranged in a fixed manner, and an axial compressive test space for accommodating the test core (9) is formed between the axial compressive stress axis (6) and the bearing axis (8), and when the centrifugal storage box (4) is rotated to a state where the axis is parallel to the rotating connecting rod (3), the axial compressive stress axis (6) is close to the rotating connecting rod (3), and the bearing axis (8) is far away from the rotating connecting rod (3).

5. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 4, characterized in that: An axial stress control pin (11) with adjustable position is arranged in the test box (5), and the axial stress control pin (11) is used to limit the sliding range of the axial compressive stress shaft (6).

6. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 4, characterized in that: A confining pressure chamber (18) is arranged in the test box (5), the test core (9) is located in the confining pressure chamber (18), a fluid inlet pipe valve (17) and a fluid outlet pipe valve (16) are arranged in the confining pressure chamber (18), a plurality of local strain gauges (7) are arranged on the surface of the test core (9), and at least one radial chain strain gauge (12) is sleeved on the test core (9).

7. A geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 6, characterized in that: The fluid inlet pipe valve (17) and the fluid outlet pipe valve (16) are connected together to a fluid storage device for storing fluid. At least one compression impeller (19) is fixedly mounted on the shaft rotor (26). The compression impeller (19) can pump the fluid in the fluid storage device into the confining pressure chamber (18) through the fluid inlet pipe valve (17) as the shaft rotor (26) rotates.

8. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 4, characterized in that: An axial displacement extensometer (13) is arranged in the test box (5), and the axial displacement extensometer (13) is located on the side of the test core (9). Both sensing ends of the axial displacement extensometer (13) are fixedly connected to the test core (9), and the two sensing ends are distributed along the length direction of the test core (9).

9. The geological storage seepage acceleration testing machine based on magnetic levitation centrifugal technology as claimed in claim 1, characterized in that: The centrifugal storage box (4) is movably connected to the end of the rotating connecting rod (3) via a pull rope.

10. A geological burial seepage acceleration test method based on magnetic levitation centrifugal technology, based on a geological burial seepage acceleration test machine based on magnetic levitation centrifugal technology as claimed in any one of claims 1 to 9, characterized in that: The method comprises the following steps: Placing the test core (9) into the multi-field coupling test box, and placing the multi-field coupling test box into the centrifugal storage box (4); Connecting the centrifugal storage box (4) to the rotating connecting rod (3); The rotary drive mechanism (2) is used to drive the rotating connecting rod (3) to rotate, and the rotating connecting rod (3) drives the centrifugal storage box (4) and the multi-field coupling test box to rotate synchronously.

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