Underground hydrogen storage structure model test system based on optical fiber and working method

Abstract

The invention relates to an underground hydrogen storage structure model test system based on optical fibers and a working method thereof, and the system comprises a plurality of groups of lining samples which form a lining structure and are arranged at the inner side of an energy storage chamber; distributed optical fibers are embedded into the inner surface and the outer surface of the lining structure through notch grooves, and the distributed optical fibers are connected with a demodulator through leads. The counter-force unit is provided with a plurality of groups of counter-force plates, and the counter-force plates are uniformly arranged on the outer side of the lining structure and used for simulating displacement and pressure of surrounding rock in the energy storage chamber on the lining structure; the device further comprises a center counter-force cylinder arranged on the inner side of the lining structure, the center counter-force cylinder is filled with water to simulate filled high-pressure gas, and the space between the center counter-force cylinder and the lining structure is filled with water for pressure balance. Water in the center counter-force cylinder is used for simulating high-pressure gas in the underground hydrogen storage facility, the multiple groups of counter-force plates on the outermost layer are used for simulating displacement and pressure of surrounding rock on a lining structure, and the rigidity coefficient is changed by changing the displacement-stress function relation.

Description

Technical Field

[0001] The present invention relates to the technical field of underground hydrogen storage, and in particular to an optical fiber-based underground hydrogen storage structure model test system and a working method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Large-scale underground hydrogen storage systems can store excess renewable energy electricity in underground chambers during electricity consumption troughs by electrolyzing water and producing high-pressure hydrogen through compressors. During electricity consumption peaks, the high-pressure hydrogen is released and burned to discharge, playing the role of peak-shaving and valley-flattening. The structural design of the underground hydrogen storage system determines the stability and sealing of the underground chamber. If the strength of the supporting structure is insufficient, it will cause hydrogen leakage and instability of the underground structure, posing a threat to the lives and property of people at the hydrogen storage site.

[0004] In underground hydrogen storage chambers, due to the presence of high internal pressure gas and the coverage of external pressure plates, traditional underground engineering monitoring instruments cannot be used on the open surface, resulting in the inability to monitor underground hydrogen storage structures using existing technologies. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides an optical fiber-based underground hydrogen storage structure model test system and a working method, which use a simulation experiment to determine the stress-strain curve of the optical fiber monitoring system during operation.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides an optical fiber-based underground hydrogen storage structure model test system, comprising:

[0008] The lining samples have multiple groups, and the multiple groups of lining samples form a lining structure arranged inside the energy storage chamber; the inner surface and the outer surface of the lining structure are embedded with distributed optical fibers through grooves, and the distributed optical fibers are connected to the demodulator through leads;

[0009] The reaction unit has multiple groups of reaction plates, which are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock in the energy storage chamber on the lining structure; it also has a central reaction cylinder arranged on the inside of the lining structure, the inside of the central reaction cylinder is filled with water to simulate the high-pressure gas, and the space between the central reaction cylinder and the lining structure is filled with water for pressure balance.

[0010] Furthermore, it also has a water pressure loading system, which controls the water pressure by controlling the operation of the water pump and changing the water flow rate, thereby simulating the change process of high-pressure gas at different pressures in the energy storage chamber.

[0011] Furthermore, the water pressure loading system changes the amount of water filled between the central reaction cylinder and the lining structure by controlling the operation of the water pump for pressure balance.

[0012] Furthermore, each set of reaction plates is provided with a corresponding servo-controlled actuator. According to the test requirements, the servo-controlled actuator is used to drive the reaction plates to move, simulating the load sharing of underground engineering support structures with different levels of uniform surrounding rock / non-uniform surrounding rock.

[0013] Furthermore, the reaction plate is an arc surface, the shape of the arc fits the outer surface of the lining structure, and multiple groups of reaction plates are enclosed to form a simulated energy storage chamber.

[0014] Furthermore, the servo-controlled actuator is loaded using stress loading, displacement loading or stiffness loading mode to simulate different working conditions in underground engineering.

[0015] Furthermore, during the simulation of the initial geostress field in the underground engineering, the servo-controlled actuator preferentially adopts the stress loading mode; during the process of water pressure growth, the stiffness loading mode is adopted to simulate the elastic-plastic constraint support effect of the surrounding rock on the lining.

[0016] Furthermore, the stress-displacement relationship in the stiffness loading mode is determined by presetting, and the specific parameters of the corresponding stiffness loading mode are obtained by converting the deformation modulus according to the surrounding rock classification at the project site.

[0017] Furthermore, in the stiffness loading mode, the stiffness coefficient is changed by changing the functional relationship between displacement and stress.

[0018] The second aspect of the present invention provides a working method of an optical fiber-based underground hydrogen storage structure model test system, comprising the following steps:

[0019] The center reaction cylinder is filled with water at a set pressure to simulate the high-pressure gas stored in the underground hydrogen storage structure;

[0020] Multiple groups of lining samples form a lining structure and are arranged inside the energy storage chamber. The space between the central reaction cylinder and the lining structure is filled with water at a set pressure for pressure balance.

[0021] Multiple groups of reaction plates are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock on the lining structure to form an energy storage chamber. During the simulation, the inner and outer surfaces of the lining structure are used to obtain the corresponding displacement and pressure through the distributed optical fiber embedded in the grooves and output them through the demodulator.

[0022] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0023] 1. The stress-strain curve of the optical fiber monitoring system during operation is determined by means of simulation experiments. The water in the central reaction cylinder is used to simulate the high-pressure gas inside the underground hydrogen storage facility. The outermost multiple groups of reaction plates are used to simulate the displacement and pressure of the surrounding rock on the lining structure. The stiffness coefficient is changed by changing the functional relationship between displacement and stress.

[0024] 2. When the optical fiber monitoring system is not equipped with optical fibers, grooves are pre-cut on the inner and outer surfaces of the lining sample before laying out the optical fiber line, so that the reaction plate does not directly contact the optical fiber material, which will not cause the optical fiber material to be squeezed and damaged, resulting in monitoring failure. In addition, the optical fiber is pre-buried in the grooved concrete ring, which can make the damage process of optical fiber monitoring closer to the actual test process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 is a schematic top view of a pressure plate in an optical fiber-based underground hydrogen storage structure model test system provided by one or more embodiments of the present invention;

[0027] Figure 2 is a schematic diagram of a gas simulation unit in an optical fiber-based underground hydrogen storage structure model test system provided by one or more embodiments of the present invention;

[0028] Figure 3 It is a schematic diagram of arranging optical fibers on the outer surface of a lining structure according to one or more embodiments of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] Embodiment 1:

[0032] Fiber-optic based underground hydrogen storage structure model test system, including:

[0033] The lining samples have multiple groups, and the multiple groups of lining samples form a lining structure arranged inside the energy storage chamber; the inner surface and the outer surface of the lining structure are embedded with distributed optical fibers through grooves, and the distributed optical fibers are connected to the demodulator through leads;

[0034] The reaction unit has multiple groups of reaction plates, which are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock in the energy storage chamber on the lining structure; it also has a central reaction cylinder arranged on the inside of the lining structure, and the space between the central reaction cylinder and the lining structure is filled with water for pressure balance.

[0035] The reaction unit also has an end pressure plate. The lining structure is sleeved on the outside of the central reaction cylinder. If there is no central reaction cylinder occupying the space and the interior is completely filled with water, then the normal force to be borne by the end pressure plate = water pressure × end area of ​​water. The end area of ​​water is reduced through the central reaction cylinder, and the normal force is reduced, making the equipment easier to control.

[0036] In this embodiment, multiple groups of reaction plates are used to simulate surrounding rocks to form a simulated energy storage chamber, and water is filled in the energy storage chamber to simulate the high-pressure gas stored in the hydrogen storage chamber.

[0037] By using the servo response system, external stress and displacement constraints can be provided under the rules of stress control, displacement control, or stiffness control to simulate the cooperative bearing effect of surrounding rock on the lining of the hydrogen storage chamber.

[0038] The control system can monitor the displacement of the lining structure in real time under the action of internal pressure, and according to the obtained displacement, control the servo response system to provide external force that conforms to the actual scenario, simulate the dynamic response process of the support structure under different surrounding rock conditions, and reflect the coordinated deformation and response mechanism of the support structure and surrounding rock of underground engineering.

[0039] The fiber grating integrated monitoring and early warning system can complete the measurement of the lining structure with both internal and external coverage. The distributed optical fiber is embedded in the grooves on the steel bar surface and concrete surface of the lining structure, and the optical fiber is fixed with glass glue. The lead wire is led out from the sealing surface of the concrete end of the lining structure, so that the monitoring can be completed by wired mode when the inner surface is in contact with water and the outer surface is in contact with the pressure plate. Figure 3 shown.

[0040] In this embodiment, the system includes 12 reaction pressure plates and corresponding 12 servo-controlled actuators, a water pressure control system and a monitoring and early warning system; it can simulate the load sharing characteristics of underground engineering support structures under different levels and non-uniform surrounding rock conditions.

[0041] like Figure 1 As shown in the figure, 12 reaction plates are used to simulate the active support force and displacement of the surrounding rock on the lining structure. The shape of the plate is a curved surface that matches the shape of the underground engineering structure to ensure full contact with the underground energy storage structure surface. The servo-controlled actuator controls the loading displacement, loading pressure or loading stiffness to reach the preset state. The curved surface structure of the reaction plate is suitable for supporting loading of energy storage chamber support structures of different sizes, as well as simulating the surrounding rock action mechanism of underground water transfer tunnels.

[0042] 12 servo-controlled actuators are used as the power source and control system of the reaction plate. After the specific parameters of the model experiment are determined, the 12 servo-controlled actuators provide corresponding reaction forces through the displacement values ​​measured at their locations to simulate the stiffness values ​​(relationship between reaction load and measured displacement) and cooperative bearing characteristics of the surrounding rock in underground engineering. The mentioned stiffness values ​​can be changed during the experiment, including linear and nonlinear, uniform and non-uniform stiffness characteristics.

[0043] The water pressure control system is used for the high-pressure gas carried by the energy storage chamber. It stores high-pressure water in the space between the energy storage chamber and the lining structure, and increases the water pressure through compressors and water pumps to simulate the process of air being injected into the underground chamber and pressurized. Figure 2 shown.

[0044] The monitoring and early warning system is a combination of monitoring systems including water pressure monitoring, servo control actuator monitoring and model specimen monitoring.

[0045] The water pressure monitoring system measures the water pressure in the cavity in real time through a water pressure gauge installed in the water inlet channel and feeds it back to the control system. The real-time value is compared with the experimental set value, and the water pressure is controlled in real time and stops automatically when the set value is reached.

[0046] The servo-controlled actuator monitoring system is composed of a high-precision displacement sensor installed on the pressure plate and a pressure sensor installed on the servo-controlled actuator. It can monitor in real time the radial displacement of the lining model during the entire process of outward expansion after being subjected to internal water pressure, as well as the reaction force of the pressure plate on the lining structure, so as to reflect the supporting role of the surrounding rock on the lining structure in actual underground engineering.

[0047] The model specimen monitoring system refers to the full range of dynamic monitoring of different parts of the specimen, including strain, stress, and displacement. It includes monitoring materials such as bundled grating array cables, pasted distributed optical fibers, concrete strain gauges, and steel bar strain gauges, as well as monitoring and reading equipment such as fiber Bragg grating dynamic demodulators and fiber Bragg grating array strain demodulators.

[0048] In particular, the water pressure control system can be controlled according to the total flow rate or the flow rate, and the loading system can be loaded in the form of ramp wave, sine wave, square wave, custom waveform, etc. for single loading or cyclic loading to simulate the injection process of high-pressure hydrogen under different conditions.

[0049] In particular, the 12 servo-controlled actuators can be synchronized with the hydraulic control system in real time via stiffness modes.

[0050] In some specific implementations, the water pressure loading system controls the water pressure by controlling the water flow rate through the operation of a water pump to simulate the change process of high-pressure gas under actual conditions.

[0051] In some specific implementations, the servo-controlled actuator may be loaded using stress loading, displacement loading, or stiffness loading modes to simulate different working conditions in underground engineering.

[0052] In some specific implementations, the servo-controlled actuator first adopts a stress loading mode to simulate the initial geostress field in underground engineering, and then adopts a stiffness loading mode during the water pressure growth process to simulate the elastic-plastic constraint support effect of the surrounding rock on the lining.

[0053] In some specific implementations, the stress-displacement relationship in the stiffness loading mode is pre-set, and the specific parameters of the corresponding stiffness loading mode are obtained by converting the deformation modulus according to the surrounding rock classification at the engineering site.

[0054] In some specific implementations, the stiffness loading mode can simulate the change of elastic modulus after surrounding rock degradation, that is, the stiffness coefficient is changed by changing the functional relationship between displacement and stress. This process can achieve real-time dynamic adjustment.

[0055] In some specific implementations, the loading platen of the servo-controlled actuator is a circular arc surface, which is suitable for loading deformation of a circular tunnel support structure.

[0056] In some specific implementations, the combined support structure experimental model is made of steel plate + reinforced concrete, and the steel plate + reinforced concrete specimen is used to simulate the underground engineering support structure. By controlling the servo response system to provide external forces that meet the actual scenario, the dynamic response process of the support structure under different surrounding rock conditions is simulated to reflect the coordinated deformation and response mechanism of the underground engineering support structure-surrounding rock.

[0057] In some specific implementations, the specific monitoring arrangement of the model experiment is as follows:

[0058] Grating array optical cables are bundled on the outer surface of the steel plate, distributed optical fibers and steel strain gauges are pasted on the surface of the steel bars by cutting grooves, and distributed optical fibers and steel strain gauges are pasted on the outer surface of the concrete by cutting grooves.

[0059] The strain gauge value is read through the dynamic and static signal test and analysis system, the measured value of the distributed optical fiber is read through the fiber grating dynamic demodulator, and the measured value of the grating array optical cable is read through the fiber grating array strain demodulator.

[0060] Embodiment 2:

[0061] The working method of the optical fiber-based underground hydrogen storage structure model test system comprises the following steps:

[0062] The center reaction cylinder is filled with water at a set pressure to simulate the high-pressure gas stored in the underground hydrogen storage structure;

[0063] Multiple groups of lining samples form a lining structure and are arranged inside the energy storage chamber. The space between the central reaction cylinder and the lining structure is filled with water at a set pressure for pressure balance.

[0064] Multiple groups of reaction plates are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock on the lining structure to form an energy storage chamber. During the simulation, the inner and outer surfaces of the lining structure are used to obtain the corresponding displacement and pressure through the distributed optical fiber embedded in the grooves and output them through the demodulator.

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical fiber-based underground hydrogen storage structure model test system, characterized in that: include: The lining samples include a plurality of groups, and the plurality of groups of lining samples form a lining structure and are arranged inside the energy storage chamber; The inner and outer surfaces of the lining structure are grooved to embed distributed optical fibers, and the distributed optical fibers are connected to the demodulator via leads; The reaction unit has multiple groups of reaction plates, which are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock in the energy storage chamber on the lining structure; it also has a central reaction cylinder arranged on the inside of the lining structure, the inside of the central reaction cylinder is filled with water to simulate the high-pressure gas, and the space between the central reaction cylinder and the lining structure is filled with water for pressure balance.

2. The optical fiber-based underground hydrogen storage structure model test system according to claim 1, characterized in that: It also has a water pressure loading system, which controls the water pressure by controlling the operation of the water pump and changing the water flow rate, thereby simulating the change process of high-pressure gas at different pressures in the energy storage chamber.

3. The optical fiber-based underground hydrogen storage structure model test system as claimed in claim 2, characterized in that: The hydraulic loading system changes the amount of water filled between the central reaction cylinder and the lining structure by controlling the operation of the water pump for pressure balance.

4. The optical fiber-based underground hydrogen storage structure model test system according to claim 1, characterized in that: Each set of reaction plates is equipped with a corresponding servo-controlled actuator. According to the test requirements, the servo-controlled actuator is used to drive the reaction plates to simulate the load sharing of underground engineering support structures with different levels of uniform surrounding rock / non-uniform surrounding rock.

5. The optical fiber-based underground hydrogen storage structure model test system according to claim 1, characterized in that: The reaction plate is an arc surface, the shape of the arc fits the outer surface of the lining structure, and multiple groups of reaction plates are enclosed to form a simulated energy storage chamber.

6. The optical fiber-based underground hydrogen storage structure model test system according to claim 4, characterized in that: The servo-controlled actuator is loaded in stress loading, displacement loading or stiffness loading mode to simulate different working conditions in underground engineering.

7. The optical fiber-based underground hydrogen storage structure model test system according to claim 1, characterized in that: During the simulation of the initial geostress field in underground engineering, the servo-controlled actuator preferentially adopts the stress loading mode; during the process of water pressure growth, the stiffness loading mode is adopted to simulate the elastic-plastic constraint support effect of the surrounding rock on the lining.

8. The optical fiber-based underground hydrogen storage structure model test system according to claim 1, characterized in that: The stress-displacement relationship in the stiffness loading mode is determined by presetting, and the specific parameters of the corresponding stiffness loading mode are obtained by converting the deformation modulus according to the surrounding rock classification at the project site.

9. The optical fiber-based underground hydrogen storage structure model test system according to claim 9, characterized in that: In the stiffness loading mode, the stiffness coefficient is changed by changing the displacement-stress functional relationship.

10. A working method based on the underground hydrogen storage structure model test system according to any one of claims 1 to 9, characterized in that: The following steps are involved: The center reaction cylinder is filled with water at a set pressure to simulate the high-pressure gas stored in the underground hydrogen storage structure; Multiple groups of lining samples form a lining structure and are arranged inside the energy storage chamber. The space between the central reaction cylinder and the lining structure is filled with water at a set pressure for pressure balance. Multiple groups of reaction plates are evenly arranged on the outside of the lining structure to simulate the displacement and pressure of the surrounding rock on the lining structure to form an energy storage chamber. During the simulation, the inner and outer surfaces of the lining structure are used to obtain the corresponding displacement and pressure through the distributed optical fiber embedded in the grooves and output them through the demodulator.

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