Apparatus for real-time monitoring of evolution of cracks caused by microwaves

Abstract

An apparatus for real-time monitoring of evolution of cracks caused by microwaves, comprising a microwave power supply, a microwave generator, a connecting waveguide, a multi-cavity mold, a bearing component, a cutoff waveguide (4), and an image acquisition assembly. The microwave generator is connected to the multi-cavity mold by means of the connecting waveguide; the bearing component is arranged in the multi-cavity mold; the bearing component is used for placing a sample; the bearing component can transmit microwaves; the cutoff waveguide (4) is mounted on the multi-cavity mold; the image acquisition assembly is arranged at an outlet of the cutoff waveguide (4); and the image acquisition assembly is aligned with the sample to acquire an image of the sample. Microwaves are generated by means of the microwave generator and act on a rock sample, such that the rock sample is heated to generate cracks, and the rock sample is photographed in real time by means of the image acquisition assembly, such that the evolution of the cracks of rock during the action of the microwaves can be monitored and recorded in real time, the development and evolution law of the cracks of the rock can be observed in real time, and the volume expansion of minerals can be quantitatively evaluated.

Description

A device for real-time monitoring of microwave crack evolution Technical Field

[0001] This invention belongs to the field of rock mass crack research experiments, specifically involving a device for real-time monitoring of microwave crack evolution. Background Technology

[0002] As resource depth increases, rock strength increases nonlinearly. Mechanical methods and drilling-and-blasting methods, due to their drawbacks such as severe tool wear and significant disturbance, restrict the development of deep-earth resources. Microwaves, as a novel assisted rock-breaking technology with a wide fracturing range, high heating efficiency, and environmental friendliness, hold promise for solving these problems. However, current research on microwaves largely focuses on the analysis of rock strength and crack parameters after microwave treatment of hard rocks, lacking the capture of the real-time evolution of intermineral cracks during microwave action, resulting in a still unclear understanding of the rock failure mechanism under microwave action. Furthermore, as a highly efficient heating technology, the non-coordinated deformation of minerals during microwave action has not been thoroughly studied. Therefore, the real-time monitoring device for rock crack evolution during microwave action designed in this invention patent can not only observe the development and evolution of rock cracks in real time but also quantitatively assess mineral volume expansion. This is an important means to clarify the correlation between crack development and thermal stress, and a crucial prerequisite for deeply revealing the mechanism of microwave-assisted rock breaking, which is of great significance for promoting the application of microwave engineering. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a device for real-time monitoring of microwave crack evolution, thereby resolving the issues in the prior art. The technical solution adopted by this invention is as follows:

[0004] A device for real-time monitoring of microwave crack evolution includes: a microwave power supply, a microwave generator, a connecting waveguide, a multimode cavity, a load-bearing component, a cutoff waveguide, and an imaging acquisition component;

[0005] The microwave power supply is connected to the microwave generator, and the microwave generator is connected to the multimode cavity through the connecting waveguide to emit microwaves into the multimode cavity. The carrier component is disposed in the multimode cavity, and the sample is placed on the carrier component. The carrier component is microwave-transmissive. The cutoff waveguide is installed on the multimode cavity, and the imaging acquisition component is disposed at the outlet of the cutoff waveguide. The imaging acquisition component is aligned with the sample to acquire an image of the sample.

[0006] Furthermore, the connecting waveguide includes a straight waveguide and a bent waveguide connected end-to-end. The inlet end of the straight waveguide is connected to the microwave generator, and the outlet end of the bent waveguide is connected to the multimode cavity. The straight waveguide is a rectangular waveguide, and its dimensions satisfy the following formula conditions: λ / 2 < a < λ, 0 < b < λ / 2, 0.6λ < a < λ, b = a / 2, a ≥ 0.7λ.

[0007] Integration yields: a = 0.7λ, b = (0.4 ~ 0.5)a

[0008] Where f is the microwave frequency, a is the width of the straight waveguide, b is the height of the straight waveguide, and λ is the microwave wavelength.

[0009] Furthermore, the dimensions of the cutoff waveguide satisfy the following formula condition: f c =17.6×10 9 / D SE=32L / D

[0010] Among them, f c It is the cutoff frequency, D and L are the cutoff waveguide diameter and length, and SE is the shielding efficiency.

[0011] Furthermore, the multi-cavity includes an upper concave bottom shell and a lower concave top shell. The top of the upper concave bottom shell is detachably connected to the lower concave top shell. The interiors of the upper concave bottom shell and the lower concave top shell together form a cavity. A support component is provided between the upper concave bottom shell and the lower concave top shell.

[0012] Furthermore, the supporting component is a glass plate, which is horizontally arranged and its upper surface is used to place the sample;

[0013] The top of the concave bottom shell is connected to the vertically arranged cutoff waveguide, and the imaging acquisition component is located above the cutoff waveguide.

[0014] Furthermore, the supporting component includes a glass shell and a hollow cylinder;

[0015] The glass shell is annular, with a hollow cylinder disposed within its hollow portion. A first annular chamber is disposed circumferentially inside the glass shell, surrounding the hollow cylinder. A first water inlet pipe and a first drain pipe are disposed on both sides of the glass shell, communicating with the first annular chamber. The first water inlet pipe and the first drain pipe are connected to an external cooling circulation assembly to form circulating water flowing within the first annular chamber.

[0016] Furthermore, the top of the concave bottom shell is detachably connected to a top plate, the top of the top plate is connected to a cover plate, and a second annular chamber is provided between the cover plate and the top plate. The second annular chamber is connected to an external cooling circulation assembly through a second water inlet pipe and a second water outlet pipe to form flowing circulating water in the second annular chamber.

[0017] Furthermore, the cover plate and the top plate are provided with a through hollow portion, and an energy-absorbing cylinder is slidably arranged in the hollow portion. The second annular chamber is arranged around the energy-absorbing cylinder, and the energy-absorbing cylinder is filled with microwave absorbing filler. The bottom of the energy-absorbing cylinder is provided with an opening, and the opening is provided with threads. The energy-absorbing cylinder and the hollow cylinder are coaxially arranged.

[0018] The bottom of the hollow cylinder is provided with an annular toothed portion, and the bottom of the hollow portion of the glass shell is fixedly connected to a supporting toothed ring. The annular toothed portion cooperates with the supporting toothed ring to form a circumferential constraint. The hollow cylinder is used to move downward and is threadedly connected to the hollow cylinder.

[0019] Furthermore, the side of the concave bottom shell is connected to the horizontally arranged cutoff waveguide.

[0020] Furthermore, a fixing plate and a plane mirror are provided inside the concave bottom shell. The plane mirror is tilted to reflect the sample to the imaging acquisition component.

[0021] The fixed plate is rotatably connected to a horizontally arranged upper connecting rod and a lower connecting rod. The upper connecting rod is located above the lower connecting rod. The upper connecting rod and the lower connecting rod can slide through the upper concave bottom shell. One end of the two rods that protrudes through the upper concave bottom shell is movably connected to an adjusting vertical rod. The middle part of the adjusting vertical rod is rotatably connected to one end of a telescopic rod. The other end of the telescopic rod is fixedly connected to the outer side of the upper concave bottom shell.

[0022] When the upper connecting rod and the lower connecting rod slide in the same direction, the position of the plane mirror is adjusted; when the upper connecting rod and the lower connecting rod slide in opposite directions, the angle of the plane mirror is adjusted.

[0023] The present invention has the following beneficial effects: The present invention generates microwaves through a microwave generator and applies them to a rock sample, causing the rock sample to crack due to heat. The rock sample is then photographed in real time by an imaging acquisition component, which can monitor and record the evolution of cracks in the rock during the microwave action. The development and evolution of rock cracks can be observed in real time, and the mineral volume expansion can be quantitatively assessed. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 is a schematic diagram of a rectangular straight waveguide;

[0026] Figure 3 is a schematic diagram when the supporting component is a glass plate;

[0027] Figure 4 is a schematic diagram when the load-bearing components include a glass shell and a hollow cylinder;

[0028] Figure 5 is a schematic diagram of the hollow cylinder being removed;

[0029] Figure 6 is a top view of the cross-section of the glass casing. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to Figures 1-6 in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0031] As shown in Figure 1, a device for real-time monitoring of microwave crack evolution includes: a microwave power supply, a microwave generator, a connecting waveguide, a multimode cavity, a load-bearing component, a cutoff waveguide 4, and an imaging acquisition component.

[0032] The microwave power supply is connected to the microwave generator, and the microwave generator is connected to the multimode cavity through the connecting waveguide to emit microwaves into the multimode cavity. The carrier component is disposed in the multimode cavity, and the sample is placed on the carrier component. The carrier component is microwave-transmissible. The cutoff waveguide 4 is mounted on the multimode cavity, and the imaging acquisition component is disposed at the outlet of the cutoff waveguide 4. The imaging acquisition component is aligned with the sample to acquire an image of the sample.

[0033] The microwave power supply and microwave generator are existing technologies. The microwave power supply and microwave generator are connected by a cable. The microwave power supply is connected to a power source, and a high-frequency power switch controls the supply of power to the microwave generator. The microwave generator contains an excitation cavity, a magnetron, and a filament power supply. First, the microwave power supply preheats the filament power supply. During preheating, the filament power supply heats the cathode of the magnetron through current. When heated to a sufficiently high temperature, the magnetron cathode generates an electron beam. This electron beam is emitted from the accelerating electrode and guided by the magnetic field generated by the magnetic field ring, forming a bent electron beam. The energy change produced by the interaction between this electron beam and the magnetic field generates microwave radiation. At this point, the microwave is in TEM mode. The microwave propagates into the excitation cavity in the form of electromagnetic waves. When the microwave is transmitted into the excitation cavity through a coupler, the coupler, through a specific guiding action, converts the TEM mode microwave into TE mode. 10 Model, (TE) 10 The mold has the characteristics of simple and stable field structure, wide bandwidth and low loss, and transmits to a rectangular straight waveguide.

[0034] Furthermore, the connecting waveguide includes a straight waveguide and a bent waveguide connected end to end, with the inlet end of the straight waveguide connected to the microwave generator and the outlet end 6 of the bent waveguide connected to the multimode cavity.

[0035] The straight waveguide is a rectangular waveguide, taking into account the microwave generator transmitting TE. 10 Therefore, a rectangular straight waveguide needs to satisfy: (1) Only transmit the dominant mode TE. 10(2) Sufficient power capacity (increasing power capacity while avoiding breakdown); (3) Low loss. Specific dimensions satisfy the following calculation formula: λ / 2<a<λ 0<b<λ / 2 0.6λ<a<λ b=a / 2 a≥0.7λ

[0036] Integration yields: a = 0.7λ, b = (0.4 ~ 0.5)a

[0037] Where f is the microwave frequency, a is the width of the straight waveguide, and b is the height of the straight waveguide; λ is the microwave wavelength, calculated using the formula: c = λf, where f is the microwave power supply frequency. For example, for a 2.45 GHz microwave power supply, λ = 12.24 cm is calculated. The derivation of the above formula involves electromagnetic field analysis. The reasons for selecting the parameters are: 1. The waveguide in this design needs to suppress higher-order modes; 2. Low loss; 3. High transmission power. Microwave transmission is performed using different modes. The TE required by this invention... 10 Model, TE 10 The lowest cutoff frequency is found in the first modulus, while the cutoff frequencies of other higher-order moduli are higher. This value ensures that the TE (transmission frequency) is optimal. 10 Mode transmission. Low loss means avoiding energy loss as heat, reflection, or radiation during microwave energy transmission, ensuring that the microwave energy enters the cavity to the maximum extent and acts on the rock. High transmission power means avoiding excessive reflected power, resulting in more power entering the cavity.

[0038] As shown in Figure 2, for example, when the microwave frequency f is 2.45 GHz, the corresponding wavelength λ is 12.24 cm. Calculations show that a is 8.568 cm and b ranges from 3.4272 to 4.284 cm. Considering the dimensions of standard rectangular waveguide components, a BJ26 type rectangular waveguide is selected, with a = 8.636 cm and b = 4.318 cm.

[0039] Additionally, the microwave generator can be connected to a straight waveguide via a circulator. The circulator is equipped with a water load, which has an inlet and an outlet. The inlet water pipe of the water load connects to a water pump, which is placed in a water tank. Water circulation is achieved through negative pressure. The outlet water pipe of the water load connects to the inlet of the microwave generator. After cooling the magnetron, the water returns to the water tank through the outlet pipe. The water in the water load is primarily used to absorb reflected microwaves, preventing them from entering the microwave generator through the circulator and damaging the magnetron. Furthermore, a microwave power meter is installed on the straight waveguide to monitor the incident and reflected power in real time.

[0040] Furthermore, the dimensions of the cutoff waveguide 4 satisfy the following formula condition: f c =17.6×10 9 / D SE=32L / D

[0041] Among them, f cIt is the cutoff frequency, D and L are the cutoff waveguide diameter and length, and SE is the shielding efficiency.

[0042] The cutoff waveguide 4 serves two purposes: it prevents microwaves from damaging instruments within the multimode cavity while ensuring that the imaging acquisition components can successfully capture images of the rock inside the cavity. The cutoff waveguide 4 is a hollow cylindrical structure.

[0043] The imaging acquisition component is existing technology and can be a high-speed camera, camera, video recorder, or an optical microscope or electron microscope with a microscope camera. The imaging end 5 of the imaging acquisition component is located at the external opening of the cutoff waveguide 4. In addition, to improve the imaging quality, a supplementary light can be installed above the supporting component, and an infrared thermal imager can also be installed, with the acquisition end of the infrared thermal imager located above the supporting component.

[0044] The test specimens of this invention can be a single rock sample or a pile of granular rocks.

[0045] Furthermore, the multi-mold cavity includes an upper concave bottom shell 1 and a lower concave top shell 2. The top of the upper concave bottom shell 1 is detachably connected to the lower concave top shell 2 by bolts. The interiors of the upper concave bottom shell 1 and the lower concave top shell 2 together form a cavity. A bearing member is provided between the upper concave bottom shell 1 and the lower concave top shell 2. The bearing member is clamped and fixed between the upper concave bottom shell 1 and the lower concave top shell 2, allowing bolts to pass through the bearing member to fix it.

[0046] The bearing component of the present invention includes two embodiments:

[0047] As shown in Figure 3, Embodiment 1 of the bearing component: The bearing component is a glass plate 3, which is horizontally arranged and its upper surface is used to place the sample;

[0048] The top of the concave bottom shell 1 is connected to the vertically arranged cutoff waveguide 4, and the imaging acquisition component is located above the cutoff waveguide 4.

[0049] In Example 1, the glass plate 3 can support more rock samples, allowing granular rock samples to be laid flat on the glass plate 3, or supporting larger rock samples.

[0050] As shown in Figures 4-6, Embodiment 2 of the bearing component: The bearing component includes a glass shell 21 and a hollow cylinder 22;

[0051] The glass shell 21 is annular, and a hollow cylinder 22 is disposed inside its hollow portion. A first annular chamber is disposed circumferentially inside the glass shell 21, and the first annular chamber is disposed around the hollow cylinder 22. A first water inlet pipe 11 and a first drain pipe 10 are disposed on both sides of the glass shell 21, which are connected to the first annular chamber. The first water inlet pipe 11 and the first drain pipe 10 are connected to an external cooling circulation assembly to form circulating water flowing in the first annular chamber.

[0052] Specifically, the outer edges of the top and bottom surfaces of the glass shell 21 abut against the upper end face of the upper concave bottom shell 1 and the lower end face of the lower concave top shell 2, respectively. An opening for a first annular chamber is provided on the outer circumferential surface of the glass shell 21, and this opening is fixedly connected to a metal ring plate 27 to prevent microwave leakage. The metal ring plate 27 and the first annular chamber constitute an annular sealed chamber. The first water inlet pipe 11 and the first drain pipe 10 are located on both sides of the glass shell 21.

[0053] The external cooling circulation assembly is existing technology, including a cooling water tank 7 and a pump body. Both the first inlet pipe 11 and the first outlet pipe 10 are connected to the cooling water tank 7 and driven by the pump body to circulate the internal cooling medium. The cooling medium is pure water. A heat exchange pipe can be installed inside the cooling water tank 7, which can be connected to a storage tank (not shown in the figure). The heat exchange pipe transfers heat from the cooling medium in the cooling water tank 7 to the storage tank, thus recovering waste heat and cooling the cooling medium. The cooling medium forms a circulating water system within the cooling water tank 7, the first inlet pipe 11, the first outlet pipe 10, and the first annular chamber.

[0054] In Example 2, since only the microwaves passing through the hollow cylinder 22 have an effect on the sample, the circulating water inside the glass shell 21 can absorb the excess microwave energy and convert it into heat to form a waste heat recovery function. Furthermore, it can concentrate the microwaves more effectively on the test inside the hollow cylinder 22. Compared to Example 1, Example 2 is suitable for rock test cases with smaller dimensions.

[0055] A support glass plate 23 can be fixedly connected inside the hollow cylinder 22. The support glass plate 23 and the top surface of the hollow cylinder 22 form a groove for placing the sample.

[0056] Furthermore, the top of the concave bottom shell 1 is detachably connected to a top plate 26, and the top of the top plate 26 is connected to a cover plate 25. A second annular chamber is provided between the cover plate 25 and the top plate 26. The second annular chamber is connected to an external cooling circulation assembly through a second water inlet pipe 8 and a second drain pipe 9 to form flowing circulating water in the second annular chamber.

[0057] The second annular chamber forms the second energy recovery mechanism of this invention. Microwaves exiting upwards from the hollow cylinder 22 penetrate the top plate 26 and are absorbed by the circulating water within the second annular chamber. The second inlet pipe 8 and the second outlet pipe 9 connect the cooling water tank 7 and the pump body. The cover plate 25 may be provided with a downward-facing annular groove, which cooperates with the top plate 26 to form the second annular chamber.

[0058] Furthermore, the cover plate 25 and the top plate 26 are provided with a through hollow portion, and an energy-absorbing cylinder 12 is slidably arranged in the hollow portion. The second annular chamber is arranged around the energy-absorbing cylinder 12, and the energy-absorbing cylinder 12 is filled with microwave absorbing filler. The bottom of the energy-absorbing cylinder 12 is provided with an opening, and the opening is provided with threads. The energy-absorbing cylinder 12 and the hollow cylinder 22 are coaxially arranged.

[0059] The bottom of the hollow cylinder 22 is provided with an annular toothed portion, and the bottom of the hollow portion of the glass shell 21 is fixedly connected to the support toothed ring 24. The annular toothed portion cooperates with the support toothed ring 24 to form a circumferential constraint. The hollow cylinder 22 is used to move downward and is threadedly connected to the hollow cylinder 22.

[0060] Specifically, both the cover plate 25 and the top plate 26 are annular, and their hollow portions are fitted with the energy-absorbing cylinder 12 with a clearance, forming a certain sliding damping. This sliding damping eliminates the self-weight of the energy-absorbing cylinder 12, and the energy-absorbing cylinder 12 only moves when it is manually slidable. Alternatively, rubber rings can be provided on the inner wall surfaces of the hollow portions of the cover plate 25 and the top plate 26 to form sliding damping.

[0061] Both the annular toothed part and the supporting toothed ring 24 are annular. The supporting toothed ring 24 supports the annular toothed part and the hollow cylinder 22. With the cooperation of the annular toothed part and the supporting toothed ring 24, the circumferential constraint of the hollow cylinder 22 is formed.

[0062] When the hollow cylinder 22 needs to be removed to take out the sample, as shown in Figure 5, the energy-absorbing cylinder 12 moves downwards to fit onto the hollow cylinder 22, and rotates the energy-absorbing cylinder 12 so that the hollow cylinder 22 is threadedly connected to the energy-absorbing cylinder 12. Then, the energy-absorbing cylinder 12 moves upwards so that it passes through the cover plate 25 and the top plate 26, and the energy-absorbing cylinder 12 can be taken out, which facilitates the replacement of the test sample.

[0063] In Embodiment 2, the side of the concave bottom shell 1 is connected to the horizontally arranged cutoff waveguide 4. Compared to Embodiment 1, Embodiment 2 has less impact on the microwaves of the imaging acquisition component.

[0064] Furthermore, a fixing plate 18 and a plane mirror 19 are provided inside the concave bottom shell 1. The plane mirror 19 is tilted and used to reflect the sample to the imaging acquisition component.

[0065] The fixed plate 18 is rotatably connected to the horizontally arranged upper connecting rod 16 and lower connecting rod 17. The upper connecting rod 16 is located above the lower connecting rod 17. The upper connecting rod 16 and the lower connecting rod 17 can slide through the upper concave bottom shell 1. One end of the two protruding from the upper concave bottom shell 1 is movably connected to the adjusting vertical rod 15. The middle part of the adjusting vertical rod 15 is rotatably connected to one end of the telescopic rod 20. The other end of the telescopic rod 20 is fixedly connected to the outer side of the upper concave bottom shell 1.

[0066] When the upper connecting rod 16 and the lower connecting rod 17 slide in the same direction, the position of the plane mirror 19 is adjusted; when the upper connecting rod 16 and the lower connecting rod 17 slide in opposite directions, the angle of the plane mirror 19 is adjusted.

[0067] Specifically, the plane mirror 19 facilitates the acquisition of sample images by the imaging acquisition component. One end of the upper connecting rod 16 and the lower connecting rod 17 is hinged to the fixed plate 18, and the other end can be connected to a hinge seat. The hinge seat is slidably mounted on a slide rail, which is installed on the adjusting vertical rod 15. When the adjusting vertical rod 15 rotates, the upper connecting rod 16 and the lower connecting rod 17 slide in opposite directions to adjust the angle of the plane mirror 19. When the horizontally mounted telescopic rod 20 extends or retracts, the plane mirror 19 moves horizontally to adjust its position. By adjusting the position and angle of the plane mirror 19, the imaging acquisition component can acquire images, and images from different positions within the experiment can be captured.

[0068] In this invention, the glass plate 3, the glass shell 21, the supporting glass plate 23, the top plate 26, and the hollow cylinder 22 are preferably made of quartz glass. Quartz glass is a microwave-transparent and high-temperature resistant material that will not affect the transmission and distribution of microwaves.

[0069] After connecting all the instruments, the microwave power and time are set to begin the experiment. The computer records infrared images and optical microscope images during the microwave experiment. During this process, special attention must be paid to synchronizing the infrared imaging recording time with the microscope imaging time to facilitate analysis of the time and temperature at which cracks formed.

[0070] This invention generates microwaves through a microwave generator and applies them to a rock sample, causing the rock sample to crack upon heating. The rock sample is then photographed in real time by an imaging acquisition component, enabling real-time monitoring and recording of the crack evolution during the microwave application process. This allows for real-time observation of the development and evolution of rock cracks and quantitative assessment of mineral volume expansion.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, substitutions, or variations made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for real-time monitoring of microwave crack evolution, characterized in that, include: Microwave power supply, microwave generator, connecting waveguide, multimode cavity, carrier component, cutoff waveguide (4) and imaging acquisition component; The microwave power supply is connected to the microwave generator, and the microwave generator is connected to the multimode cavity through the connecting waveguide to emit microwaves into the multimode cavity. The carrier component is arranged inside the multimode cavity, and the sample is placed on the carrier component. The carrier component is microwave-transmissible. The cutoff waveguide (4) is installed on the multimode cavity, and the imaging acquisition component is arranged at the outlet of the cutoff waveguide (4). The imaging acquisition component is aligned with the sample to acquire the image of the sample.

2. The device for real-time monitoring of microwave crack evolution according to claim 1, characterized in that, The connecting waveguide includes a straight waveguide and a bent waveguide connected end to end. The entrance end of the straight waveguide is connected to the microwave generator, and the exit end (6) of the bent waveguide is connected to the multimode cavity. The straight waveguide is a rectangular waveguide, and its dimensions satisfy the following formula conditions: λ / 2<a<λ 0<b<λ / 2 0.6λ<a<λ b=a / 2 a≥0.7λ Integration yields: a = 0.7λ b = (0.4 ~ 0.5)a Where f is the microwave frequency, a is the width of the straight waveguide, b is the height of the straight waveguide, and λ is the microwave wavelength.

3. The device for real-time monitoring of microwave crack evolution according to claim 1, characterized in that, The dimensions of the cutoff waveguide (4) satisfy the following formula condition: f c =17.6×10 9 / D SE=32L / D Among them, f c It is the cutoff frequency, D and L are the cutoff waveguide diameter and length, and SE is the shielding efficiency.

4. The device for real-time monitoring of microwave crack evolution according to claim 1, characterized in that, The multi-mold cavity includes an upper concave bottom shell (1) and a lower concave top shell (2). The top of the upper concave bottom shell (1) is detachably connected to the lower concave top shell (2). The upper concave bottom shell (1) and the lower concave top shell (2) together form a chamber. A support component is provided between the upper concave bottom shell (1) and the lower concave top shell (2).

5. The device for real-time monitoring of microwave crack evolution according to claim 4, characterized in that, The supporting component is a glass plate (3), which is horizontally arranged and its upper surface is used to place the sample; The top of the concave bottom shell (1) is connected to the vertically arranged cutoff waveguide (4), and the imaging acquisition component is located above the cutoff waveguide (4).

6. The device for real-time monitoring of microwave crack evolution according to claim 4, characterized in that, The supporting component includes a glass shell (21) and a hollow cylinder (22); The glass shell (21) is annular, and a hollow cylinder (22) is disposed inside its hollow portion. A first annular chamber is disposed circumferentially inside the glass shell (21), and the first annular chamber is disposed around the hollow cylinder (22). A first water inlet pipe (11) and a first drain pipe (10) are disposed on both sides of the glass shell (21) to connect the first annular chamber. The first water inlet pipe (11) and the first drain pipe (10) are connected to an external cooling circulation assembly to form a circulating water flow in the first annular chamber.

7. The device for real-time monitoring of microwave crack evolution according to claim 6, characterized in that, The top of the concave bottom shell (1) is detachably connected to a top plate (26), and the top of the top plate (26) is connected to a cover plate (25). A second annular chamber is provided between the cover plate (25) and the top plate (26). The second annular chamber is connected to an external cooling circulation assembly through a second water inlet pipe (8) and a second drain pipe (9) to form flowing circulating water in the second annular chamber.

8. The device for real-time monitoring of microwave crack evolution according to claim 7, characterized in that, The cover plate (25) and the top plate (26) are provided with a through hollow part, and an energy-absorbing cylinder (12) is slidably arranged in the hollow part. The second annular chamber is arranged around the energy-absorbing cylinder (12), and the energy-absorbing cylinder (12) is filled with microwave absorbing filler. The bottom of the energy-absorbing cylinder (12) is provided with an opening, and the opening is provided with threads. The energy-absorbing cylinder (12) and the hollow cylinder (22) are arranged coaxially. The bottom of the hollow cylinder (22) is provided with an annular toothed part, and the bottom of the hollow part of the glass shell (21) is fixedly connected to the support toothed ring (24). The annular toothed part cooperates with the support toothed ring (24) to form a circumferential constraint. The hollow cylinder (22) is used to move downward and is threadedly connected to the hollow cylinder (22).

9. A device for real-time monitoring of microwave crack evolution according to any one of claims 6-8, characterized in that, The side of the concave bottom shell (1) is connected to the horizontally arranged cutoff waveguide (4).

10. The device for real-time monitoring of microwave crack evolution according to claim 9, characterized in that, The concave bottom shell (1) is provided with a fixing plate (18) and a plane mirror (19) inside. The plane mirror (19) is tilted and used to reflect the sample to the imaging acquisition component. The fixed plate (18) is rotatably connected to the horizontally arranged upper connecting rod (16) and lower connecting rod (17). The upper connecting rod (16) is located above the lower connecting rod (17). The upper connecting rod (16) and the lower connecting rod (17) can slide through the upper concave bottom shell (1). One end of the two protruding from the upper concave bottom shell (1) can be movably connected to the adjusting vertical rod (15). The middle part of the adjusting vertical rod (15) can be rotatably connected to one end of the telescopic rod (20). The other end of the telescopic rod (20) is fixedly connected to the outer side of the upper concave bottom shell (1). When the upper connecting rod (16) and the lower connecting rod (17) slide in the same direction, the position of the plane mirror (19) is adjusted; when the upper connecting rod (16) and the lower connecting rod (17) slide in opposite directions, the angle of the plane mirror (19) is adjusted.

Images