Porous medium visual clamping device for energy and heat storage PIV (particle image velocimetry) experiment

Abstract

The invention discloses a porous medium visual clamping device for an energy storage and heat storage PIV experiment in the technical field of energy storage and heat storage PIV experiment equipment, and the porous medium visual clamping device specifically comprises a base, a base is detachably fixed on the base, a positioning groove is formed in the base, the positioning groove is used for containing a sample, the sample abuts against the inner wall of the positioning groove, and the inner wall of the positioning groove is fixedly connected with the base. A cover plate is detachably fixed to the positioning groove and abuts against the sample, and an observation groove is formed in the cover plate. A fluid inlet and a fluid outlet are formed in the two sides of the base and are symmetrically distributed relative to the center line of the base. One end of the fluid inlet is communicated with a water supply source, the other end is communicated with the positioning groove, one end of the fluid outlet is communicated with the positioning groove, the other end is communicated with the outside, and a flow guide structure is arranged between the fluid inlet and the positioning groove. The influence of an entrance effect is eliminated to a certain extent through the flow guide structure, and the accuracy of data collected in an experiment is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage and thermal energy storage PIV experimental equipment technology, and in particular to a porous media visualization clamping device for energy storage and thermal energy storage PIV experiments. Background Technology

[0002] Research on underground reservoir energy and thermal storage is a key path to solving the problem of intermittent renewable energy consumption and revitalizing idle resources such as depleted oil and gas reservoirs and abandoned oil wells. The fluid flow and heat transfer characteristics within porous media are crucial research directions for optimizing the efficiency of energy and thermal storage systems, and particle image velocimetry (PIV) technology is a core means of visually observing this process. Current PIV experiments in energy and thermal storage suffer from technical deficiencies in porous media samples and their supporting clamping devices, such as difficulty in characterizing porous media channels and cracks, poor sealing compatibility between the sample and the clamping device, low thermal conductivity between the sample and the base, and the absence or improper placement of observation windows. These deficiencies severely restrict the accuracy of experimental research.

[0003] In related technologies, when conducting energy storage and thermal storage PIV experiments, including experiments simulating pore seepage and crack flow scenarios in porous media, the related technologies usually use constant pressure liquid injection for seepage experiments. At the inlet, a pure threaded connection is usually used, which will cause flow velocity distortion at the inlet, which is not conducive to maintaining the stability of high pressure fluid. Summary of the Invention

[0004] This application discloses a porous media visualization clamping device for PIV experiments in energy storage and thermal storage, in order to solve the technical problem of flow velocity distortion at the fluid inlet when porous media are subjected to seepage experiments in related technologies.

[0005] To solve the above problems, this application adopts the following technical solution: This application provides a porous media visualization clamping device for energy storage and thermal storage PIV experiments, specifically including a base, a base plate detachably fixed on the base, a positioning groove provided on the base, the positioning groove is used to accommodate the sample, the sample is pressed against the inner wall of the positioning groove, a cover plate detachably fixed on the positioning groove, the cover plate is pressed against the sample, and an observation groove is opened on the cover plate. The base has fluid inlets and fluid outlets on both sides, and the fluid inlets and fluid outlets are symmetrically distributed with respect to the center line of the base; One end of the fluid inlet is connected to the water supply source, and the other end is connected to the positioning groove. One end of the fluid outlet is connected to the positioning groove, and the other end is connected to the outside. A flow guiding structure is provided between the fluid inlet and the positioning groove.

[0006] Furthermore, the bottom of the positioning groove is provided with an immersion inlet and an immersion outlet; Gaskets are provided at both the immersion inlet and immersion outlet, and the gaskets are pressed tightly against the sample.

[0007] Furthermore, both the immersion inlet and immersion outlet are trapezoidal openings, and the side of the immersion inlet is connected to the flow guiding structure.

[0008] Furthermore, the flow guiding structure includes a connector and a DC groove. The connector is connected to the fluid inlet, the DC groove is connected to the positioning groove, and an arc-shaped groove is provided between the connector and the DC groove. One end of the arc-shaped groove is connected to the connector, and the other end is connected to the DC groove.

[0009] Furthermore, the width of the arc-shaped groove gradually increases from the connection joint and the DC groove towards the middle position.

[0010] Furthermore, the inner wall of the arc-shaped groove is provided with several adjustment grooves, all of which are perpendicular to the bottom of the arc-shaped groove.

[0011] Furthermore, the edge of the observation groove smoothly transitions to the surface of the sample.

[0012] Furthermore, the base includes a seat body, a positioning groove located at the center of the top surface of the seat body, and a cover plate that can completely cover the top surface of the seat body.

[0013] Furthermore, the bottom of the seat is provided with a bottom step, which is at least partially embedded in the base.

[0014] Furthermore, the base is equipped with thermal detection components, which penetrate the base and are distributed at the bottom of the positioning groove.

[0015] The technical solution adopted in this application can achieve the following beneficial effects: This application uses a cover plate and a base to clamp the sample in the middle, controlling the positions of the fluid inlet and outlet to maintain the experimental pressure by using the sample as an intermediate component. However, the high-pressure water flow in the experiment can easily lead to pressure unevenness, thus affecting the experimental structure. Therefore, this application incorporates a flow guiding structure to effectively eliminate the inlet effect to a certain extent, improving the accuracy of the data collected during the experiment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the porous media visualization clamping device disclosed in the embodiments of this application; Figure 2 This is a front view of the porous media visualization clamping device disclosed in the embodiments of this application; Figure 3This is a side cross-sectional view of the porous media visualization clamping device disclosed in the embodiments of this application; Figure 4 This is a front cross-sectional view of the porous media visualization clamping device disclosed in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the base disclosed in the embodiments of this application; Figure 6 This is a cross-sectional structural schematic diagram of the base disclosed in the embodiments of this application; Figure 7 This is an exploded structural diagram of the porous media visualization clamping device disclosed in the embodiments of this application.

[0018] In the picture: 100. Cover plate; 110. Observation slot; 200. Sample; 300, base; 310, fluid inlet; 320, seat body; 330, fluid outlet; 340, trapezoidal opening; 350, gasket; 360, arc-shaped guide groove; 361, connector; 362, arc-shaped groove; 363, direct current groove; 370, immersion inlet; 380, positioning groove; 390, immersion outlet; 400. Thermal detection components; 500. Base. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described in detail below. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] To study energy and thermal storage in underground reservoirs, it is necessary to conduct point-of-entry (PIV) experiments, which mainly rely on exploring the various physical and chemical properties of samples from the corresponding reservoir. Among these experiments, seepage experiments can demonstrate the performance of the reservoir represented by the sample when subjected to the seepage of high-pressure fluids.

[0022] In related techniques, this experiment is typically conducted using simple extrusion with a percolating fluid. Because there is no observation window, further research on the sample's changes can only be conducted after the experiment is complete; the sample's state during the experiment cannot be observed.

[0023] Through research, the inventors discovered that this was due to the fact that the opening of the observation port and the maintenance of seepage pressure could not be effectively balanced due to the poor sealing of the clamping device.

[0024] During seepage experiments, the clamping device needs to achieve an effective seal of 15 MPa. The inventors discovered that related technologies typically utilize the device structure to withstand the sealing pressure before applying the seepage pressure to the sample. However, by directly using the sample as part of the clamping device, an observation port can be created to monitor changes in the sample during the experiment while ensuring a proper seal.

[0025] The sample underwent processing, specifically as follows: The selected high-quality outcrop rock samples were machined into 75mm×25mm×7mm cuboid reference specimens using a CNC diamond wire cutting machine. The specimen surface was treated using a three-step process: rough grinding, fine grinding, and polishing. Rough grinding used a 200-grit diamond wheel (to remove surface defects), fine grinding used 800-grit silicon carbide sandpaper (to reduce surface undulations), and finally polishing with an alumina suspension (0.5μm particle size) to a roughness Ra≤0.8μm to avoid flow velocity disturbance caused by surface protrusions. After these operations, two stepped circular holes were drilled 10mm from the short side of the specimen to serve as fluid channels. The stepped shape was designed to ensure uniform fluid flow into the crack or pore throat area. The pore simulation area was precisely controlled using a high-speed sandblasting system, while the crack simulation area was processed using pulsed fiber laser etching technology.

[0026] In view of this, the following is in conjunction with the appendix Figures 1 to 7 This application provides a detailed description of a porous media visualization clamping device for PIV experiments in energy storage and thermal storage through specific embodiments and application scenarios.

[0027] This application provides a porous media visualization clamping device for PIV (Porous Media Visualization and Holding) experiments, specifically including a base 500, which serves as the foundation for connecting to the outside environment. A base 300 is detachably fixed to the base 500, allowing for easy operation and maintenance. The base 300 has a positioning groove 380 for accommodating a sample 200. The sample 200 abuts against the inner wall of the positioning groove 380, ensuring complete filling. This positioning groove 380 not only fixes the sample in place but also enhances the sealing performance between the sample 200 and the groove. A cover plate 100 is detachably fixed to the positioning groove 380, abutting against the sample 200. The cover plate 100 effectively seals the sample 200 within the positioning groove 380, facilitating the permeation experiment. The cover plate 100 is provided with an observation slot 110, through which the changes of the sample 200 during the experiment can be effectively observed.

[0028] In this embodiment, the sample 200 can be regarded as a sealing element between the cover plate 100 and the positioning groove 380. It serves as both the experimental sample 200 and a sealing element in the positioning groove 380 to increase the sealing pressure, thereby effectively completing the experiment while improving the sealing performance.

[0029] In this embodiment, the base 500 can be positioned upright, upside down, or at an angle, thereby increasing the number of experimental methods to simulate and obtain data of the sample 200 under different postures. However, the primary experimental method is the one with the base 500 inverted.

[0030] The base 300 has fluid inlets 310 and fluid outlets 330 on both sides, and the fluid inlets 310 and fluid outlets 330 are symmetrically distributed with respect to the center line of the base 300. Fluid is introduced through the fluid inlets 310 and discharged from the fluid outlets 330 after seepage is completed. The symmetrical distribution of the fluid inlets 310 and fluid outlets 330 enables the fluid to maintain a uniform flow state.

[0031] One end of the fluid inlet 310 is connected to a water supply source, and the other end is connected to the positioning groove 380. One end of the fluid outlet 330 is connected to the positioning groove 380, and the other end is connected to the outside. When the liquid entering from the fluid inlet 310 flows through the abrupt change region of the flow channel cross-section, turbulent flow phenomena arise due to the interaction of viscous and inertial forces. In high-pressure fluid experiments, the fluid possesses high kinetic energy and high momentum characteristics. When the high-pressure fluid enters the positioning groove 380 through the fluid inlet 310, it induces distortion phenomena such as local eddies, flow stream contraction, and velocity distortion. These distortion phenomena lead to uneven velocity distribution of the fluid entering the positioning groove 380, severely affecting the accuracy and comparability of experimental data. Consequently, the clamping device cannot meet the application requirements of high-pressure, high-precision fluid experiments.

[0032] In this embodiment, a flow guiding structure is provided between the fluid inlet 310 and the positioning groove 380. This flow guiding structure guides the high-pressure fluid to smoothly change direction along its trajectory, thereby balancing the fluid's kinetic energy and viscous force and preventing the aforementioned distortion phenomena.

[0033] In some embodiments of this application, the bottom of the positioning groove 380 is provided with an inlet 370 and an outlet 390. Positioning the inlet 370 and outlet 390 at the bottom of the positioning groove 380 effectively improves the pressure resistance of the sample 200. Furthermore, during this process, the sample 200 can still complete the seepage test from the inlet 370 to the outlet 390.

[0034] Gaskets 350 are provided at both the immersion inlet 370 and the immersion outlet 390, and the gaskets 350 press tightly against the sample 200. The gaskets 350 not only improve the sealing between the immersion inlet 370 and the immersion outlet 390 and the sample 200, but also protect the surface of the sample 200 from damage.

[0035] In some embodiments of this application, both the immersion inlet 370 and the immersion outlet 390 are trapezoidal openings 340, and the side of the immersion inlet 370 is connected to the flow guiding structure. Both the immersion inlet 370 and the immersion outlet 390 are trapezoidal openings 340, and the diameter of the end of the immersion inlet 370 and the immersion outlet 390 that contacts the sample 200 is larger than the diameter of the end of the original sample 200. The increased diameter of the immersion inlet 370 effectively maintains the stability of the fluid when in contact with the sample 200, avoiding flow turbulence caused by fluid reverberation after contact with the sample 200; the contraction of the diameter of the immersion outlet 390 effectively maintains the stability of the high pressure during the seepage process within the clamping device.

[0036] For example, taking the inverted case as an example, the embodiments of this application can be manufactured using stainless steel, which has excellent corrosion resistance, high strength and good machinability.

[0037] The cover plate 100 adopts a rectangular flat plate structure, with dimensions precisely calculated to be 77mm long × 50mm wide × 4mm thick. This thickness ensures structural strength while minimizing obstruction of the observation optical path. Its core functional areas are designed as follows: First, the observation slot 110 serves as the observation window: a rectangular observation slot 110, 55mm long × 12mm wide, is located in the center of the cover plate 100; the slot size matches the observation field of view of the PIV system, ensuring clear capture of fluid flow during the experiment. Second, a tight-fitting structure is used for sealing: φ5mm through holes are symmetrically drilled at the four corners of the cover plate 100, which, together with M5 hexagonal socket bolts, achieve a tight connection with the base 300.

[0038] At corresponding positions on the left and right ends of the clamping device, two 4mm diameter (tolerance ±0.1mm) internal thread interfaces are machined on the base 300 as fluid inlet 310 and fluid outlet 330. The thread type is M4×0.7. The interfaces and the external booster pump pipeline adopt a 1:16 conical sealing structure, and the conical contact pressure can reach more than 20MPa. The sealing surface is coated with polytetrafluoroethylene (PTFE) coating (coating thickness 50-80μm) by plasma spraying. This coating has both low friction coefficient and high sealing performance, and the sealing accuracy of the device reaches 10-6 Pa·m. 3 The fluid maintains pressure at 15MPa for 24 hours without leakage, fully meeting the requirements of high-pressure testing. A flow-guiding structure is installed inside the threaded interface to guide the high-pressure fluid into the positioning groove 380 at a uniform speed, with a flow velocity error controlled within ≤5%. This flow-guiding structure effectively solves the flow velocity distortion problem caused by the "inlet effect" in traditional clamping devices. Comparative experimental data shows that the flow velocity deviation of traditional structures without flow-guiding grooves can reach over 20%.

[0039] In some embodiments of this application, the flow guiding structure is an arc-shaped flow guiding channel 360, which includes a connector 361 and a direct current channel 363. The connector 361 connects to the fluid inlet 310, and the direct current channel 363 connects to the positioning groove 380. An arc-shaped channel 362 is provided between the connector 361 and the direct current channel 363. One end of the arc-shaped channel 362 connects to the connector 361, and the other end connects to the direct current channel 363. The width of the arc-shaped channel 362 gradually increases from the point where the connector 361 and the direct current channel 363 connect to the middle position. Through flow channel transition optimization, the arc-shaped flow guiding channel 360 can form a natural arc transition with the flow channel of the fluid inlet 310, thereby changing the right-angle abrupt interface of the traditional structure. Utilizing the smoothness of the arc transition, the local resistance coefficient of the fluid is reduced, thereby guiding the fluid to smoothly turn along a preset trajectory, effectively suppressing the contraction of the flow stream and the generation of eddies, and also uniformly controlling the flow velocity gradient. When the high-pressure fluid enters the arc-shaped guide channel 360, the arc-shaped structure of the arc-shaped guide channel 360 will generate a uniform guiding force on the fluid, so that the velocity gradient of the fluid gradually becomes uniform along the flow direction, which changes the phenomenon of sudden velocity change in the traditional structure and realizes the controllability of the fluid flow state.

[0040] In some embodiments of this application, the inner wall of the arc-shaped groove 362 is provided with several adjusting grooves, all of which are perpendicular to the bottom of the arc-shaped groove 362. The adjusting grooves effectively prevent fluids from interfering with each other within the arc-shaped groove 362, thereby improving the smoothness of fluid flow. The adjusting grooves further suppress the aforementioned distortion phenomenon.

[0041] In some embodiments of this application, the edge of the observation groove 110 smoothly transitions to the surface of the sample 200. The edge of the observation groove 110 adopts a rounded transition with a radius of 1 mm to avoid stress concentration.

[0042] In some embodiments of this application, the base 300 includes a seat 320, a positioning groove 380 located at the center of the top surface of the seat 320, and a cover plate 100 capable of completely covering the top surface of the seat 320. The cover plate 100, the seat 320, and the positioning groove 380 form an effective experimental space for completing the experiment, thereby facilitating the completion of the seepage experiment.

[0043] In some embodiments of this application, the base 320 has a bottom step, which is at least partially embedded in the base 500. By partially embedding the bottom step into the base 500, the base 300 can be effectively limited, and the base 300 can maintain its positional stability during the experiment, and deformation can be avoided to a certain extent.

[0044] The base 300 is divided into a wide section and a narrow section: the wide section measures 105mm in length, 50mm in width, and 14mm in thickness, serving as the main load-bearing area; the bottom step, forming the narrow section, measures 80mm in length, 50mm in width, and 6mm in thickness. A positioning groove 380 for the sample 200 is centrally located at the top of the wide section. The groove is designed to be 76mm in length, 26mm in width, and 2mm in depth (1mm larger in length and width than the standard sample 200, with a depth tolerance of ±0.03mm). The inner wall of the groove is finely ground to a thickness of Ra≤0.8μm to prevent horizontal displacement of the sample 200 during the experiment.

[0045] In some embodiments of this application, a thermal detection component 400 is provided on the base 300. The thermal detection component 400 penetrates the base 300 and is distributed at the bottom of the positioning groove 380. Five φ3mm temperature detection holes with a depth of 20mm are drilled at equal intervals along the fluid flow direction on one side of the wide section of the base 300. The hole positions correspond to the fluid inlet 310, the front end of the sample 200, the middle part of the sample 200, the rear end of the sample 200, and the fluid outlet 330, respectively. A PT100 platinum resistance temperature sensor (measurement accuracy ±0.1℃) can be inserted simultaneously. Four M5 internal threaded holes (17mm deep) are machined on the top of the base 300 corresponding to the through hole position of the cover plate 100 for fastening the cover plate 100. At the same time, four M5 adjusting screws are installed at the bottom of the narrow section of the base 300. During the experiment, the device needs to be inverted to adapt to the inverted microscope of the PIV system. The height can be adjusted within the range of 0-10mm by rotating the adjusting screws to ensure that the flow area of ​​the sample 200 is accurately focused with the microscope lens.

[0046] For example, in the specific experiment of this application embodiment, the base 300 is placed horizontally, and a washer 350 is placed at the immersion inlet 370 of the positioning groove 380 of the base 300 as a sealing ring. The processed sample 200 is placed smoothly into the positioning groove 380, ensuring that the sample 200 is in close contact with the inner wall of the positioning groove 380 on all sides, with no horizontal displacement, and the processed surface of the sample 200 (including the pore / crack area) facing upwards. The cover plate 100 is aligned with the top of the base 300, so that the four corner through holes of the cover plate 100 are coaxially aligned with the M5 internal thread holes of the base 300, and the observation window accurately covers the seepage area of ​​the sample 200 to avoid obstructing the observation light path. M5 hexagonal bolts are passed through the through holes of the cover plate 100 and screwed into the internal thread holes of the base 300 in sequence, and tightened gradually according to the principle of diagonal and uniform tightening to ensure that the cover plate 100 and the base 300 are tightly fitted and the seal is fully compressed; after tightening, check that the gap between the cover plate 100 and the base 300 is uniform and there is no warping. Invert the assembled device and adjust its height by rotating the four M5 adjusting screws on the bottom of the narrow section of the base 300 to ensure that the seepage area of ​​the sample 200 is precisely focused with the microscope lens. Connect the pump line to the M4×0.7 internal thread interface on the left and right ends of the base 300, start the booster pump, and increase the pressure inside the device to 15MPa. Maintain the pressure for 24 hours to confirm that there is no leakage.

[0047] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0048] Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0049] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A porous media visualization clamping device for PIV (Porous Media Visualization and Holding) experiments for energy and thermal storage, characterized in that, Includes a base (500), on which a base (300) is detachably fixed. The base (300) is provided with a positioning groove (380) for accommodating a sample (200). The sample (200) abuts against the inner wall of the positioning groove (380). A cover plate (100) is detachably fixed to the positioning groove (380) and abuts against the sample (200). An observation groove (110) is provided on the cover plate (100). The base (300) has a fluid inlet (310) and a fluid outlet (330) on both sides, and the fluid inlet (310) and the fluid outlet (330) are symmetrically distributed with respect to the center line of the base (300); One end of the fluid inlet (310) is connected to a water supply source, and the other end is connected to a positioning groove (380). One end of the fluid outlet (330) is connected to the positioning groove (380), and the other end is connected to the outside. A flow guiding structure is provided between the fluid inlet (310) and the positioning groove (380).

2. The porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 1, characterized in that, The bottom of the positioning groove (380) is provided with an immersion inlet (370) and an immersion outlet (390). Both the immersion inlet (370) and the immersion outlet (390) are provided with gaskets (350), which abut against the sample (200).

3. The porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 2, characterized in that, Both the immersion inlet (370) and the immersion outlet (390) are trapezoidal openings (340), and the side of the immersion inlet (370) is connected to the flow guiding structure.

4. A porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to any one of claims 1 to 3, characterized in that, The flow guiding structure includes a connector (361) and a DC groove (363). The connector (361) is connected to the fluid inlet (310), and the DC groove (363) is connected to the positioning groove (380). An arc groove (362) is provided between the connector (361) and the DC groove (363). One end of the arc groove (362) is connected to the connector (361), and the other end is connected to the DC groove (363).

5. A porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 4, characterized in that, The width of the arc-shaped groove (362) gradually increases from the connecting joint (361) and the DC groove (363) toward the middle position.

6. A porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 5, characterized in that, The inner wall of the arc-shaped groove (362) is provided with several adjustment grooves, all of which are perpendicular to the bottom of the arc-shaped groove (362).

7. A porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to any one of claims 1 to 3, characterized in that, The edge of the observation groove (110) smoothly transitions to the surface of the sample (200).

8. The porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 1, characterized in that, The base (300) includes a seat (320), the positioning groove (380) is located at the center of the top surface of the seat (320), and the cover plate (100) can fully cover the top surface of the seat (320).

9. A porous medium visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 8, characterized in that, The base (320) has a bottom step at the bottom, and the bottom step is at least partially embedded in the base (500).

10. A porous media visualization clamping device for PIV experiments of energy storage and thermal storage according to claim 1, characterized in that, The base (300) is provided with a thermal detection component (400), which is inserted into the base (300) and distributed at the bottom of the positioning groove (380).

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