Inter-particle static and dynamic liquid bridge measuring system and method

Abstract

The invention discloses a system and a method for measuring static and dynamic liquid bridges among three particles or double-ellipsoid particles, and belongs to the field of micro-force measurement. The system comprises a supporting module, a displacement adjusting module, a liquid bridge volume control module, a micro-force measuring module, a data acquisition and image processing module and a particle placing device, the horizontal and vertical liquid bridge suction among particle swarms is measured through the deflection change of the bottom end of the downward extending beam and the microbalance, so that microscopic measurement of the liquid bridge form and mechanical properties among the double-ellipsoid particles under the condition of three particles or different inclination angles is realized, and a test idea is provided for developing more complex particle swarm suction research; and a more real experimental test means is provided for researching a microscopic soil-water characteristic rule.

Description

Technical Field

[0001] The present invention relates to a static and dynamic liquid bridge measurement system and method between particles, and in particular to a static and dynamic liquid bridge measurement system and method between three particles or double ellipsoid particles, belonging to the technical field of micro-force measurement. Background Art

[0002] Liquid bridge is a natural form produced by the interaction of solid-liquid-gas three phases at the interface when there is interstitial liquid between wet particles. Its microscopic hydraulic characteristics are the basis for studying the capillary phenomenon and mechanical properties of unsaturated soil. At present, the test of liquid bridge force is basically centered on double spherical particles. When the water content is high, adjacent liquid bridges will overlap each other and reach the "rope-like" stage. The merged liquid bridge can connect two or more particles at the same time. At this time, the double-particle liquid bridge model is no longer applicable, and it is necessary to establish a three-particle or particle group contact model. In addition, in the natural state, soil particles are often irregularly and asymmetrically distributed. Their geometric shape and particle contact state affect the liquid phase distribution in the pores, pore water pressure and surface tension, and then affect the strength and deformation characteristics of the soil. However, most of the existing experiments are based on spherical particles or round particles, which cannot describe the true shape of the particles. In order to more accurately describe non-spherical particles, scholars have tried to use tetrahedrons, ellipsoids, hyperellipsoids, polyhedrons, non-uniform free radical spline surfaces, etc. for true approximation. Among them, ellipsoids or extended super-ellipsoids have rich shape feature representations, such as elongation, flatness, edge angles and asymmetry, and are widely used in the three-dimensional reconstruction of the true shape of particles.

[0003] Since the liquid bridge force is small in value and changes rapidly, it is only significant when the particle size is <3mm. The micro-force measuring instruments suitable for physical experiments are often expensive, and the testing devices are rare. The microbalance method or cantilever beam method is mainly used. The Chinese invention patent (CN113252515A) discloses a test device and method for the tensile-compression mechanical properties of the liquid bridge between wet particles. The liquid bridge stretching, compression and cyclic tests within the set range can be carried out under the condition of automatically controlling the liquid bridge volume or matrix suction. At the same time, the industrial electron microscope and the image processing method are used to monitor the change law of the key geometric parameters of the curved liquid surface. The Chinese invention patent (CN112986059A) discloses a static and dynamic liquid bridge observation system and method between two spherical particles. The invention is based on the cantilever beam micro-force measurement method, which converts the liquid bridge force measurement into the change of the cantilever beam end deflection to realize the static and dynamic liquid bridge force measurement. Both of the above invention devices can measure the liquid bridge force between particles and its morphological changes during the tensile fracture process, but they are all centered on double spherical particles and cannot analyze multiple particles and irregular particles. In view of the above background, the present invention proposes an experimental device that can measure the mechanical properties of liquid bridges between three particles or double ellipsoid particles, in order to provide an experimental means for studying the microscopic soil-water characteristics between matrix suction and volumetric moisture content. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings, the present invention aims to provide a static and dynamic liquid bridge measurement system and method between three particles or double ellipsoid particles. By changing the deflection of the bottom end of the downward beam and using a microbalance, the horizontal and vertical liquid bridge suctions between particle groups are measured respectively. This realizes the microscopic measurement of the morphology and mechanical properties of the liquid bridges between three particles or double ellipsoid particles under different inclination conditions, provides an experimental idea for conducting more complex particle group suction research, and provides a more realistic experimental testing method for studying the microscopic soil-water characteristic laws.

[0005] The present invention uses cantilever beam micro-force measurement technology to convert the rapidly changing and tiny liquid bridge force measurement into the change of the deflection of the cantilever beam end, indirectly realizing the accurate measurement of the horizontal force of the liquid bridge, and then combining it with the vertical force read by the microbalance to realize the mechanical properties of the multi-particle liquid bridge.

[0006] The present invention provides a static and dynamic liquid bridge measurement system between particles, comprising a support module, a displacement adjustment module, a liquid bridge volume control module, a micro-force measurement module, a data acquisition and image processing module, and a particle placement device; The support module includes a vibration reduction platform and an L-shaped cantilever beam. The vibration reduction platform and the L-shaped cantilever beam are arranged in two groups on the left and right with the same structure. One or two groups are selected for the experiment as needed. An L-shaped cantilever beam is arranged above the vibration reduction platform, and the cantilever beam is supported by a microbalance and a first U-shaped slot, and the displacement adjustment modules are respectively connected to the cantilever beam. The displacement adjustment module includes a horizontal adjustment device and a height adjustment device; the horizontal adjustment device includes a worm gear, a worm, and a displacement block. The worm gear and the worm are connected at the end of the boom beam, and the displacement block is connected at the end of the worm. The horizontal boom beam is connected to the displacement block through a transversely arranged worm. The worm gear is rotated to drive the worm and the displacement block to move horizontally; the height adjustment device includes two sets of devices, a coarse adjustment device and a fine adjustment device. The coarse adjustment device includes an adjustment bracket, a clip, and a lower extension beam. The adjustment accuracy is 5mm. The lower extension beam is arranged at the end of the displacement block of the horizontal adjustment device. The downward extending beam is composed of a vertically arranged rectangular plate and a rectangular plate vertically connected at the bottom, and the side surface is an inverted T-shaped structure; the downward extending beam is fixed to the displacement block by a clamp, and the bottom of the rectangular plate at the bottom of the downward extending beam is bonded with the sample particles; the vertical position of the downward extending beam and the upper particles is adjusted by loosening the clamp; the adjusting bracket is located at the bottom of the particle placing device, and the vertical position of the lower particle can also be controlled by manually adjusting the bracket; the fine adjustment device includes an electric bevel gear lifting platform, which is placed above the adjusting bracket; the adjustment accuracy of the fine adjustment device is 0.08mm.

[0007] The liquid bridge volume control module includes a micro-propelling pump and an injection needle, and the micro-propelling pump is connected to a computer through a controller. The module is placed behind the particle placement device, and the micro-propelling pump controls the injection needle to add droplets at the top of the particle spherical cap to form a liquid bridge.

[0008] The particle placement device includes a second U-shaped slot, which is located above the electric bevel gear lifting platform, and the upper particles to be tested are in contact with the downward extension beam; the lower particles to be tested are placed in the second U-shaped slot, and the U-shaped slot is used to fix the particles to be tested by adjusting the slot spacing through the telescopic plate.

[0009] The data acquisition and image processing module includes a high-speed camera, which records the morphological changes of the inter-particle liquid bridge formation, stretching and breaking process through photos and videos. The high-speed camera is installed on a camera bracket with adjustable height, and the field of view is aligned with the particle group to be tested.

[0010] The micro-force measurement module includes a first microbalance and a second microbalance, wherein the first microbalance and the second microbalance are placed on a vibration reduction table, and a first U-shaped slot is fixed on the weighing plate of the balance, and the U-shaped slot is used to adjust the slot spacing through a telescopic plate to support the cantilever beam.

[0011] The controller is connected to the computer and can control the operating device after installing the corresponding driver.

[0012] Furthermore, the L-shaped outrigger beam is a horizontal beam, the end of which is bent into an L shape and fixed to the vibration reduction platform by bolts, and the vibration reduction platform is arranged symmetrically on the left and right.

[0013] Furthermore, one end of the worm of the level adjustment device is locked in the cantilever beam, and the other end is fixedly connected to the displacement block. The worm wheel is fixed to the end of the cantilever beam by bolts.

[0014] Furthermore, the electric bevel gear lifting platform is connected to a computer to achieve precise vertical movement of the lower particles. Specifically, the electric bevel gear lifting platform includes a glass tempered plate, an anti-skid pad, a motor, an elevator, a connecting shaft and a screw. The glass tempered plate is a rectangular structure plate, and four anti-skid pads are evenly distributed below it. The bottom of the anti-skid pad is connected to the elevator through a screw, and the four elevators are connected through a connecting shaft. The elevators are all connected to the motor and powered by the motor.

[0015] Furthermore, the adjustment bracket is a high-precision small scissor-type lifting workbench, which is used as a part of the coarse adjustment device to adjust the vertical displacement of the sample particles.

[0016] The invention can be used for measuring static and dynamic liquid bridges between three particles or double ellipsoid particles.

[0017] When three particles are used as the research object, the three-particle test is composed of three spherical particles, the centers of the three spheres are located in the same vertical plane, two of which are located at the top and one at the bottom. The particle placement device of the above-mentioned measurement system includes: a second U-shaped slot, a third microbalance; the two upper spherical particles are respectively glued under the bottom plates of the two downward extending beams, and the lower spherical particle is placed in the second U-shaped slot, the second U-shaped slot is located above the third microbalance, and the third microbalance is set above the electric bevel gear lifting platform. Furthermore, in order to facilitate the adjustment of the two upper particles, the heights of the two lower extension beams are staggered; because the particles are very close to each other, it is convenient for installation and operation, and it prevents the left and right vibration reduction platforms from contacting each other and hindering the movement of the particles.

[0018] A laser rangefinder is also provided on the side of the three-particle placement device; the laser rangefinder is arranged on the left and right sides of the downward extending beam, and the laser light spot is aimed at the midpoint of the bottom end of the downward extending beam.

[0019] When double ellipsoid particles are used as the research object, the double ellipsoid test particles are composed of upper and lower ellipsoid particles, and the centers of the two spheres are located on the same vertical line. The upper particles are glued to the bottom end of the downward extending beam, and the lower particles are clamped in the U-shaped slot. The particle placement device of the above-mentioned measurement system includes: a second U-shaped slot and an angle adjustment device, the upper ellipsoid particle is fixed under the bottom plate of the downward extending beam, and the lower ellipsoid particle is fixed in the second U-shaped slot, and an angle adjustment device is provided under the second U-shaped slot; the angle adjustment device includes a worm gear mechanism, a rotating gear, an angle disk, a support plate, an outer ring, and a packaging shell. The support plate is a steel square plate for placing particles, and a worm gear mechanism is arranged at the bottom; the outer ring is sleeved on the outer edge of the rotating gear and is connected to the bottom of the support plate by bolts to form a whole, so as to keep the worm gear and the gear in close contact at all times; the worm wheel is located above the rotating gear and is tightly meshed with it, and the worm wheel is driven to rotate by rotating the worm, thereby causing the support plate to rotate along the outer edge of the gear; the surfaces of the encapsulating shells of the worm gear mechanism and the rotating gear below are respectively provided with pointers and angle scales for indicating the inclination angle of the lower particles.

[0020] It should be noted that when the double ellipsoid particles are taken as the research object, only the support module and the displacement adjustment module on one side of the support device participate in the experiment.

[0021] The structures of the first U-shaped slot and the second U-shaped slot are the same; both are composed of a left U-shaped plate, a right U-shaped plate, a telescopic plate, and a gear. The left U-shaped plate and the right U-shaped plate are left-right symmetrical structures. The structure is described by taking the left U-shaped plate as an example, including an inclined plate, a vertical plate and two horizontal rods. The inclined plate is located at the uppermost end, and the upper end of the vertical plate is connected to the inclined plate at an angle of 110°~130°; the bottom end of the vertical plate is vertically connected to the two horizontal rods, and the two horizontal rods are arranged in parallel on the upper and lower sides of the gear, and one of the horizontal rods is provided with saw teeth; the left U-shaped plate and the right U-shaped plate are The two horizontal rods are staggered and contact with the gears, among which the horizontal rod with serrations is meshed with the gears, and the horizontal rod without serrations is located outside the horizontal rod with serrations; the telescopic plate is a hollow movable structure, an elliptical hole is provided inside the telescopic plate, half of the ellipse is serrated, the gear is embedded in the telescopic plate and fixed to the bottom plate below by bolts, the gear is respectively meshed with the serrations in the telescopic plate, and with the serrations on the horizontal rods of the left U-shaped plate and the right U-shaped plate; that is, the upper, lower and right sides of the gear are respectively meshed with the rack, and stretching the telescopic plate drives the left and right U-shaped plates to move.

[0022] The gear has thickness, and the U-shaped plate is above the telescopic plate. The two are not in the same plane. The left U-shaped plate has an upper horizontal rod with serrations that mesh with the gear, and the right U-shaped plate has a lower horizontal rod with serrations that mesh with the gear. The lower horizontal rod of the left U-shaped plate is located on the outside of the right U-shaped plate, and the upper horizontal rod of the right U-shaped plate is located on the outside of the left U-shaped plate; the horizontal rod without serrations is slightly shorter. This design makes the U-shaped plate tend to be balanced and stable to prevent lateral twisting.

[0023] The left and right plates of the U-shaped slot are in an 'embracing' structure, with gears tightly meshing with the serrations on the U-shaped plate, and a plate on top to maintain stability, allowing for flexible placement of particles of different shapes and sizes.

[0024] Furthermore, the support end of the cantilever beam is supported on the microbalance through a U-shaped slot to form an outrigger beam structure; in order to increase the support reaction force caused by the vertical force of the liquid bridge, the support is arranged as close to the end as possible.

[0025] The present invention provides a method for measuring static and dynamic liquid bridges between particles. When the object is to measure the morphology and mechanical properties of liquid bridges between three particles, the method comprises the following steps: Step 1: Build a static and dynamic measurement system for the liquid bridge between three particles; Step 2: Adjust the three particles to the set positions through the height and level adjustment devices in sequence; Step 3: The upper and lower spherical particles are brought closer together by fine-tuning the lifting device controlled by a computer, and a liquid drop is added to the apex of the spherical crown of the lower particle by using the injection needle of a micro-propellant pump. After the needle is retracted, the upper particle is lowered again until the liquid droplets overlap each other between the three particles to form a liquid bridge, and the initial reading of the lower extension beam and the initial reading of the microbalance are recorded by a laser rangefinder; Step 4: The upper and lower particles are gradually separated by fine-tuning the lifting device controlled by a computer, and the liquid bridge is stretched until it breaks. During this period, the laser rangefinder records the horizontal deflection of the bottom of the extension beam, and the high-speed camera records the morphology of the entire process of stretching and breaking the liquid bridge; Step 5: Calculate the horizontal suction of the liquid bridge indirectly through the horizontal deflection of the extended beam, and read the real-time size of the vertical suction of the liquid bridge through a microbalance; at the same time, according to the morphological records, apply image processing technology to invert the geometric characteristic parameters of the liquid bridge.

[0026] The present invention also provides a method for measuring static and dynamic liquid bridges between double ellipsoid particles, comprising the following steps: Step 1: Build a static and dynamic measurement system for the liquid bridge between double ellipsoid particles; Step 2: The two ellipsoid particles are adjusted to the set positions by the height and level adjustment devices in turn, and the upper and lower ellipsoid particles are aligned by the high-speed camera; Step 3: Place the lower ellipsoid particle on the second U-shaped slot and fix it on the upper side of the support plate of the angle adjustment device by bolts. Turn the angle adjustment device to rotate the support plate to the set angle. After the self-weight deformation of the beam stabilizes, place the U-shaped slot on the first microbalance so that it just contacts the bottom surface of the beam, and adjust the balance to zero at the same time. Step 4: The upper and lower ellipsoid particles are brought closer together by fine-tuning the lifting device controlled by a computer, and a liquid drop is added to the top of the crown of the lower ellipsoid particle using the injection needle of a micro-propellant pump. After the needle is retracted, the upper ellipsoid particle is lowered again until the liquid drop overlaps the two ellipsoid particles to form a liquid bridge, and the initial reading of the first microbalance is recorded at this time; Step 5: The upper and lower ellipsoid particles are gradually separated by fine-tuning the lifting device controlled by a computer. The geometric morphology of the entire process of liquid bridge stretching and breaking is recorded by a high-speed camera; and the magnitude of the liquid bridge suction is read by a microbalance.

[0027] When measuring double ellipsoid particles, only one vibration reduction table is needed, and the laser rangefinder and the second microbalance are removed. The lower ellipsoid particle is clamped in the second U-shaped slot, and the bottom plate of the U-shaped slot is fixedly connected to the support plate of the angle adjustment device below by bolts. By turning the angle adjustment device, the support plate is rotated to the set angle. The size of the liquid bridge suction is read by the microbalance on the vibration reduction table, and the test steps are basically the same as above. Since the worm gear mechanism itself has self-locking properties, the worm gear cannot drive the worm to reverse, so that the inclination angle of the support plate can always remain constant during the rotation process.

[0028] Beneficial effects of the present invention: (1) The present invention expands the current two-particle liquid bridge force measurement device to three-particle devices, and can measure the horizontal and vertical components of the liquid bridge suction respectively, providing an experimental idea for conducting more complex particle group suction research.

[0029] (2) Microscopic measurement of the liquid bridge morphology and mechanical properties of ellipsoidal particles at different inclination angles was achieved.

[0030] (3) Through the cantilever beam micro-force measurement technology, the rapidly changing and tiny liquid bridge force is converted into the change of the deflection at the end of the cantilever beam, which indirectly realizes the accurate measurement of the liquid bridge force and can clearly record the morphological changes of the liquid bridge during the stretching and fracture process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the static and dynamic liquid bridge measurement system between three particles of the present invention; Figure 2 It is a partial schematic diagram of a particle placement device of the double ellipsoid particle inter-liquid bridge measurement system of the present invention; Figure 3 It is a schematic diagram of the electric bevel gear lifting platform of the present invention; Figure 4 It is a partial schematic diagram of the displacement block of the static and dynamic liquid bridge measurement system between particles of the present invention; Figure 5 It is a partially enlarged front view of the angle adjustment device of the double ellipsoid particle inter-liquid bridge measurement system of the present invention; Figure 6 for Figure 5 Right view of; Figure 7 It is a schematic diagram of the liquid bridge between three particles of the present invention; Figure 8 It is a front view of the U-shaped slot of the present invention; Fig. 9 It is a top view of the U-shaped slot of the present invention.

[0032] In the figure: 1-extension beam, 2-bolt, 3-vibration reduction table, 4-first U-shaped slot, 5-first microbalance, 6-worm gear, 7-worm, 8-displacement block, 9-down extension beam, 10-fastening bolt, 11-clamp, 12-upper spherical particle, 13-lower spherical particle, 14-second U-shaped slot, 15-third microbalance, 16-laser rangefinder, 17-electric bevel gear lifting platform, 18-adjustment bracket, 19-high-speed camera, 20-computer, 21-micro propulsion pump, 22-second microbalance, 23-angle adjustment device, 24-upper ellipsoid particles, 25-lower ellipsoid particles; 1701-glass tempered plate, 1702-anti-slip pad, 1703-motor, 1704-elevator, 1705-connecting shaft, 1706-screw; 2301-support plate, 2302-worm, 2303-rotating gear, 2304-worm wheel, 2305-outer ring, 2306-angle disk, 2307-packaging shell; 401-gear, 402-right U-shaped plate, 403-telescopic plate, 404-left U-shaped plate. DETAILED DESCRIPTION

[0033] The present invention is further illustrated by the following examples, but is not limited to the following examples.

[0034] like Figures 1 to 9 As shown, a static and dynamic liquid bridge measurement system between particles includes a support module, a displacement adjustment module, a liquid bridge volume control module, a micro-force measurement module, a data acquisition and image processing module, and a particle placement device; The support module includes a vibration reduction platform 3 and an L-shaped cantilever beam 1. The vibration reduction platform 3 and the L-shaped cantilever beam 1 are arranged in two groups on the left and right with the same structure. One or two groups are selected for the experiment as needed. An L-shaped cantilever beam is arranged above the vibration reduction platform, and the cantilever beam is supported by a microbalance and a first U-shaped slot 4. Figure 1 As shown, a first U-shaped slot 4 is arranged above the first microbalance 5; displacement adjustment modules are connected to the cantilever beam 1 respectively; the displacement adjustment module includes a horizontal adjustment device and a height adjustment device; the horizontal adjustment device includes a worm wheel 6, a worm 7, and a displacement block 8. The worm wheel 6 and the worm 7 are connected at the end of the cantilever beam, and the displacement block 8 is connected at the end of the worm 7. The horizontal cantilever beam 1 is connected to the displacement block 8 through the transversely arranged worm 7. By rotating the worm wheel, the worm and the displacement block are driven to move horizontally; the height adjustment device includes two sets of devices for coarse adjustment and fine adjustment. The coarse adjustment device includes an adjustment bracket 18, a clamping piece 11, and a lower extension beam 9. The adjustment accuracy is 5mm. The lower extension beam 9 is arranged at the end of the displacement block 8 of the horizontal adjustment device. The lower extension beam is composed of a vertically arranged rectangular plate and a rectangular plate vertically connected to the bottom, and the side is an inverted T-shaped structure; the lower extension beam 9 is fixed to the displacement block 8 by a clamping piece 11 and a fastening bolt 10 (see Figure 4 ), the bottom of the rectangular plate at the bottom of the downward extending beam is glued to the upper particles; the vertical position of the downward extending beam and the upper particles is adjusted by loosening the clamp; the adjusting bracket 18 is located at the bottom of the particle placing device, and the vertical position of the lower particles can also be controlled by manually adjusting the bracket; the fine adjustment device includes an electric bevel gear lifting platform 17, which is placed above the adjusting bracket 18; the adjustment accuracy of the fine adjustment device is 0.08mm.

[0035] Specifically, the size of the downward extension beam 9 can be selected as follows: the vertically arranged rectangular plate: 150mm high, 30mm wide, and 0.1mm thick, the rectangular plate vertically connected at the bottom: 5mm long, 5mm wide, and 1mm thick, made of high-flexibility stainless steel. The cross-sectional size should be such that the downward extension beam has a large horizontal deflection under micro-force, and no obvious deformation occurs under vertical load. The particles should preferably be polished spheres of soda-lime glass with the physical properties of soil or sand. At the beginning of each test, the surface of the particles is cleaned with 99% ethanol, and wait for a period of time for the ethanol to completely evaporate to avoid mixing with the test liquid.

[0036] The liquid bridge volume control module includes a micro-propelling pump 21 and an injection needle. The micro-propelling pump 21 is connected to the computer 20 through a controller and can be selected with a lead of 1 mm and a rate of 0.01 mm / min to 150 mm / min. The module is placed behind the particle placement device, and the micro-propelling pump controls the injection needle to add droplets at the top of the particle spherical cap to form a liquid bridge.

[0037] The particle placement device includes a second U-shaped slot 14, which is located above the electric bevel gear lifting platform 17, and the upper particles to be tested are in contact with the downward extension beam; the lower particles to be tested are placed in the second U-shaped slot, and the U-shaped slot is used to fix the particles to be tested by adjusting the slot spacing through the telescopic plate.

[0038] The data acquisition and image processing module includes a high-speed camera 19, which records the morphological changes of the inter-particle liquid bridge formation, stretching and breaking process through photos and videos. The high-speed camera 19 is installed on a camera support with adjustable height, and the field of view is aimed at the particle group to be tested.

[0039] The micro-force measurement module includes a first microbalance 5 and a second microbalance 22, wherein the first microbalance 5 and the second microbalance 22 are placed on a vibration reduction platform 3, and a first U-shaped slot 4 is fixed on the weighing plate of the balance, and the first U-shaped slot 4 is used to support the cantilever beam by adjusting the slot spacing through a telescopic plate. The precision of the first and second microbalances is 0.01 mg, and the range is 95 g.

[0040] The controller is connected to the computer and can control the operating device after installing the corresponding driver.

[0041] Furthermore, the L-shaped outrigger beam 1 is a horizontal beam, the end of which is bent into an L shape and fixed to a vibration reduction platform 3 by bolts 2. The vibration reduction platform is arranged symmetrically on the left and right.

[0042] Furthermore, one end of the worm 7 of the level adjustment device is sleeved in the cantilever beam 1, and the other end is fixedly connected to the displacement block 8. The worm wheel 6 is fixed to the end of the cantilever beam by bolts.

[0043] Furthermore, the electric bevel gear lifting platform 17 is connected to the computer 20 to achieve precise vertical movement of the lower particles. Specifically, the electric bevel gear lifting platform 17 includes a glass tempered plate 1701, an anti-skid pad 1702, a motor 1703, an elevator 1704, a connecting shaft 1705 and a screw 1706. The glass tempered plate is a rectangular structure plate, and four anti-skid pads are evenly distributed below it. The bottom of the anti-skid pad is connected to the elevator through a screw, and the four elevators are connected through a connecting shaft. The elevators are all connected to the motor and powered by the motor.

[0044] Furthermore, the adjustment bracket 18 is a high-precision small scissor-type lifting workbench, which is used as a part of the coarse adjustment device to adjust the vertical displacement of the sample particles.

[0045] The structures of the first U-shaped slot 4 and the second U-shaped slot 14 mentioned above are the same; both are composed of a left U-shaped plate 404, a right U-shaped plate 402, a telescopic plate 403, and a gear 401. The left U-shaped plate 404 and the right U-shaped plate 402 are left-right symmetrical structures. The structure is described by taking the left U-shaped plate 404 as an example, including an inclined plate, a vertical plate and two horizontal rods. The inclined plate is located at the uppermost end, and the upper end of the vertical plate is connected to the inclined plate at an angle of 120°. The bottom end of the vertical plate is vertically connected to the two horizontal rods, and the two horizontal rods are arranged in parallel on the upper and lower sides of the gear, and one of the horizontal rods is provided with serrations. The two horizontal rods of the left U-shaped plate and the right U-shaped plate are staggered and contact the gear, wherein the horizontal rod with serrations is engaged with the gear, and the horizontal rod without serrations is located outside the horizontal rod with serrations. The telescopic plate 403 is a hollow movable structure with an elliptical hole inside. Half of the ellipse is serrated. The gear is embedded in the telescopic plate and fixed to the bottom plate below by bolts. The gear 401 is respectively meshed with the serrations in the telescopic plate 403 and the serrations on the horizontal bars of the left U-shaped plate 404 and the right U-shaped plate 402; that is, the upper, lower and right sides of the gear are respectively meshed with the racks of other components, and stretching the telescopic plate drives the left and right U-shaped plates to move.

[0046] like Fig. 9 As shown, the gear has thickness, the U-shaped plate is above the telescopic plate, and the two are not in the same plane. The left U-shaped plate has an upper horizontal rod with serrations that mesh with the gear, and the right U-shaped plate has a lower horizontal rod with serrations that mesh with the gear. The lower horizontal rod of the left U-shaped plate is located on the outside of the right U-shaped plate, and the upper horizontal rod of the right U-shaped plate is located on the outside of the left U-shaped plate; the horizontal rod without serrations is slightly shorter. This design makes the U-shaped plate tend to be balanced and stable to prevent lateral twisting.

[0047] The left and right plates of the U-shaped slot are in an "embracing" structure. The gears are tightly meshed with the racks on the U-shaped plate, and the plate on top is used to maintain stability. Particles of different shapes and sizes can be flexibly clamped. In addition, the gears should have a smaller meshing gap to keep the particles and the U-shaped plate in a relatively tight state to ensure that the particles are not loose.

[0048] Furthermore, the support end of the cantilever beam 1 is supported on the first or second microbalance through the first U-shaped slot to form a cantilever beam structure; in order to increase the support reaction force caused by the vertical force of the liquid bridge, the support is arranged as close to the end as possible.

[0049] like Figure 1As shown, one end of the L-shaped cantilever beam 1 is supported on the first microbalance 5 through the first U-shaped slot 4 to form a cantilever beam structure; in order to increase the supporting reaction force caused by the vertical force of the liquid bridge, the balance is arranged as close to the end as possible. Since the balance range is very small, when the device is built, after the self-weight deformation of the cantilever beam 1 structure is stable, the first U-shaped slot 4 is placed so that it is in contact with the bottom surface of the beam to minimize the self-weight reaction force transmitted to the balance.

[0050] The support reaction force at the microbalance can be obtained according to the force method in structural mechanics. The specific calculation formula is: (1) In the formula, , The support reaction force is: (2) In the formula, X 1 is the reaction force at the support; F is the vertical force of the liquid bridge; l is the beam length; x is the displacement of the balance support from the beam end; EI is the beam stiffness; δ 11 express X 1 is the unit force acting alone on the basic structure along the support X Displacement in 1 direction; 1p It means that the vertical force of the liquid bridge is applied alone to the basic structure along the support. X 1 direction displacement. M1 represents the displacement of the basic structure in X 1=1 bending moment; M p It represents the bending moment of the basic structure under the vertical force of the liquid bridge.

[0051] It can be seen that the closer the balance support is to the fixed end of the L-shaped cantilever beam, the more obvious the amplification effect of the support reaction force is.

[0052] The liquid bridge measurement system provided by the present invention can be used for measuring static and dynamic liquid bridges between three particles or double ellipsoid particles. The following is an explanation through specific embodiments: Embodiment 1: Provide a static and dynamic measurement system and method for three-particle liquid When three particles are used as the research object, the three-particle test is composed of three spherical particles, the centers of the three spheres are located in the same vertical plane, two of which are located at the top and one at the bottom. The particle placement device of the above-mentioned measurement system includes: a second U-shaped slot, a third microbalance; the two upper spherical particles are respectively glued under the bottom plates of the two downward extending beams, and the lower spherical particle is placed in the second U-shaped slot, the second U-shaped slot is located above the third microbalance, and the third microbalance is set above the electric bevel gear lifting platform. Furthermore, in order to facilitate the adjustment of the two upper particles, the heights of the two lower extension beams are staggered, such as Figure 1 As shown, the end of the left outrigger beam is lower than that of the right end; because the particles are very close to each other, it is convenient for installation and operation, and it prevents the left and right vibration reduction platforms from contacting each other and hindering the movement of particles.

[0053] A laser rangefinder is also provided on the side of the three-particle placement device; the laser rangefinder is arranged on the left and right sides of the downward extending beam, and the laser light spot is aimed at the midpoint of the bottom end of the downward extending beam.

[0054] use Figure 1 The three-particle liquid static and dynamic measurement system provided includes the following test steps: Step 1: Build a static and dynamic measurement system for three-particle liquid; Step 2: Adjust the three particles to the set positions through the height and level adjustment devices in sequence; Step 3: The computer 20 controls the fine adjustment lifting device 17 to gradually bring the upper and lower spherical particles closer together, and the micro-advancing pump 21 adds a droplet at the apex of the spherical cap of the lower spherical particle 13. After the needle is retracted, the upper spherical particle 12 is lowered until the droplets overlap each other between the three particles to form a liquid bridge, and the initial reading of the extension beam 9 and the initial reading of the microbalance are recorded by the laser rangefinder 16; Step 4: The computer 20 controls the fine adjustment lifting device 17 to move the upper spherical particle 12 away from the lower spherical particle 13. The lower spherical particle 13 is fixed in the second U-shaped slot 14. The particles are slowly lifted step by step in the vertical direction with a step length of 0.02 mm. After the balance reading is stable, the micro-force (vertical component of suction) is read and the corresponding displacement is recorded until the liquid bridge breaks. The laser rangefinder 16 is used to record the deflection of the extension beam 9 during the whole process, and the high-speed camera 19 is used to record the morphological changes of the entire liquid bridge stretching and breaking process; Step 5: indirectly calculate the horizontal suction of the liquid bridge through the horizontal deflection of the downward extension beam 9, and read the real-time size of the vertical suction of the liquid bridge through a microbalance; record the entire process of formation, stretching and fracture of the liquid bridge between the two balls through a high-speed camera 19, and apply image processing technology to obtain the geometric parameters of the liquid bridge morphology.

[0055] Embodiment 2: Provide a static and dynamic measurement system and method for a double ellipsoid particle liquid When the double ellipsoid is used as the research object, the double ellipsoid test particle is composed of an upper ellipsoid particle and a lower ellipsoid particle, and the centers of the two ellipsoid particles are located on the same vertical line. The particle placement device of the above-mentioned measurement system includes: a second U-shaped slot and an angle adjustment device, the upper ellipsoid particle is glued to the bottom end of the downward extension beam, and the lower ellipsoid particle is clamped in the second U-shaped slot. An angle adjustment device is provided below the second U-shaped slot.

[0056] When measuring double ellipsoid particles, only one vibration reduction table 3 is required, and the laser rangefinder 16 and the second microbalance 15 are removed. The lower particle is clamped in the U-shaped slot 14 and fixed to the support plate of the angle adjustment device 23 by bolts. The support plate is rotated to the set angle by turning the angle adjustment device 23. The magnitude of the liquid bridge suction is read by the first microbalance 5 on the vibration reduction table 3, and the test steps are basically the same as above.

[0057] The angle adjustment device 23 includes a support plate 2301, a worm 2302, a worm wheel 2304, a rotating gear 2303, an outer ring 2305, an angle plate 2306, and a packaging shell 2307. The support plate 2301 is a steel square plate for placing particles, and a worm gear mechanism is arranged at the bottom; the outer ring 2305 is sleeved on the outer edge of the rotating gear 2303, and is fixed to the bottom of the support plate 2301 by bolts to form a gear shell, which is used to keep the worm wheel 2304 and the rotating gear 2303 in close contact at all times; the worm wheel 2304 is located above the rotating gear 2303 and is closely meshed with it, and the worm wheel 2304 is driven to rotate by rotating the worm 2302, thereby rotating the support plate 2301 along the outer edge of the gear; the surfaces of the worm gear mechanism and the packaging shell 2307 of the rotating gear 2303 below are respectively provided with a pointer and an angle plate 2306, which are used to indicate the tilt angle of the particles. Since the worm gear mechanism itself has a self-locking property, the worm wheel 2304 cannot drive the worm 2302 to reverse, so that the inclination angle of the support plate 2301 can always remain constant during the rotation process.

[0058] The method for measuring static and dynamic liquid bridges between double ellipsoid particles includes the following steps: Step 1: Build a static and dynamic measurement system for the liquid bridge between double ellipsoid particles; Step 2: The two ellipsoid particles are adjusted to the set positions by the height and level adjustment devices in turn, and the upper and lower ellipsoid particles are aligned by the high-speed camera 19; Step 3: The lower ellipsoid particle 25 is clamped on the second U-shaped clamping groove 14 and fixed on the upper side of the support plate of the angle adjustment device 23 by bolts. The angle adjustment device is turned to rotate the support plate to the set angle. After the self-weight deformation of the beam is stable, the first U-shaped clamping groove is placed on the first microbalance so that it is in contact with the bottom surface of the beam, and the balance is adjusted to zero at the same time; Step 4: The computer 20 controls the fine adjustment lifting device to bring the upper and lower ellipsoid particles closer together, and the injection needle of the micro-propelling pump 21 is used to add a droplet at the top of the spherical crown of the lower ellipsoid particle 25. After the needle is retracted, the upper ellipsoid particle 24 is lowered again until the droplets overlap each other between the two ellipsoid particles to form a liquid bridge, and the initial reading of the first microbalance 5 is recorded at this time; Step 5: The upper and lower ellipsoid particles are gradually separated by controlling the fine adjustment lifting device through the computer 20. The geometric morphology of the entire process of liquid bridge stretching and breaking is recorded by means of a high-speed camera 19; and the magnitude of the liquid bridge suction is read by the first microbalance 5.

[0059] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A static and dynamic liquid bridge measurement system between particles, characterized by: It includes a support module, a displacement adjustment module, a liquid bridge volume control module, a micro-force measurement module, a data acquisition and image processing module, and a particle placement device; The support module includes a vibration reduction platform and an L-shaped cantilever beam, and the vibration reduction platform and the L-shaped cantilever beam are arranged in two groups on the left and right with the same structure; an L-shaped cantilever beam is arranged above the vibration reduction platform, and the cantilever beam is supported by a microbalance and a first U-shaped slot, and the displacement adjustment modules are respectively connected to the cantilever beam; The displacement adjustment module includes a horizontal adjustment device and a height adjustment device; the horizontal adjustment device includes a worm gear, a worm, and a displacement block. The worm gear and the worm are connected at the end of the boom beam, and the displacement block is connected at the end of the worm. The horizontal boom beam is connected to the displacement block through a transversely arranged worm, and the worm and the displacement block are driven to move horizontally by rotating the worm gear; the height adjustment device includes two sets of devices for coarse adjustment and fine adjustment. The coarse adjustment device includes an adjustment bracket, a clip, and a lower extension beam. The lower extension beam is arranged at the end of the displacement block of the horizontal adjustment device. The lower extension beam is composed of a vertically arranged rectangular plate and a rectangular plate vertically connected to the bottom, and the side surface is an inverted T-shaped structure; the adjustment bracket is located at the bottom of the particle placing device, and the vertical position of the lower particle can be controlled by manually adjusting the bracket; the fine adjustment device includes an electric bevel gear lifting platform, which is placed above the adjustment bracket; The liquid bridge volume control module includes a micro-propelling pump and an injection needle, and the micro-propelling pump is connected to a computer through a controller; the module is placed behind the particle placement device, and the micro-propelling pump controls the injection needle to add droplets at the top of the particle spherical cap to form a liquid bridge; The particle placement device includes a second U-shaped slot, which is located above the electric bevel gear lifting platform, and the upper particles to be tested are in contact with the downward extension beam; the lower particles to be tested are placed in the second U-shaped slot, and the second U-shaped slot is used to fix the particles to be tested by adjusting the slot spacing through the telescopic plate; The data acquisition and image processing module includes a high-speed camera, which records the morphological changes of the inter-particle liquid bridge during the entire process of formation, stretching and fracture through photos and videos; The micro-force measurement module includes a first microbalance and a second microbalance, wherein the first microbalance and the second microbalance are placed on a vibration reduction table, and a first U-shaped slot is fixed on the weighing plate of the balance, and the U-shaped slot is used to adjust the slot spacing through a telescopic plate to support the cantilever beam.

2. The particle-to-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: The L-shaped outrigger beam is a horizontal beam, the end of which is bent into an L shape and fixed to the vibration reduction platform by bolts. The vibration reduction platform is arranged symmetrically on the left and right. One end of the worm of the horizontal adjustment device is sleeved in the cantilever beam, and the other end is fixedly connected to the displacement block; the worm wheel is fixed to the end of the cantilever beam by bolts.

3. The inter-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: The downward extension beam of the coarse adjustment device is fixed on the displacement block by a clamp, and the bottom of the rectangular plate at the bottom of the downward extension beam is bonded to the sample particles; the vertical position of the downward extension beam and the upper particles is adjusted by loosening the clamp; the adjustment accuracy of the coarse adjustment device is 5mm, and the adjustment accuracy of the fine adjustment device is 0.08mm.

4. The particle-to-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: The electric bevel gear lifting platform is connected to a computer to achieve precise vertical movement of the lower particles; the electric bevel gear lifting platform includes a glass tempered plate, an anti-skid pad, a motor, an elevator, a connecting shaft and a screw rod; the glass tempered plate is a rectangular structural plate, and four anti-skid pads are evenly distributed below it. The bottom of the anti-skid pad is connected to the elevator through a screw rod, and the four elevators are connected through a connecting shaft. The elevators are all connected to the motor and powered by the motor.

5. The inter-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: The adjustment bracket is a high-precision small scissor-type lifting workbench; the high-speed camera is installed on the height-adjustable camera bracket, and the field of view is aimed at the particle group to be tested.

6. The particle-to-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: When the particle to be tested is a three-spherical particle, the three sphere centers are located in the same vertical plane, two of which are located at the top and one at the bottom; The particle placement device also includes a third microbalance; the two upper spherical particles are respectively glued under the bottom plates of the two downward extending beams, the lower spherical particles are placed in the second U-shaped slot, the second U-shaped slot is located above the third microbalance, and the third microbalance is arranged above the electric bevel gear lifting platform; in order to facilitate the adjustment of the two upper particles, the heights of the two downward extending beams are staggered; A laser rangefinder is also provided on the side of the particle placement device; the laser rangefinder is arranged on the left and right sides of the downward extending beam, and the laser light spot is aimed at the midpoint of the bottom end of the downward extending beam.

7. The particle-to-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: When the particle to be tested is a double ellipsoid particle, the double ellipsoid particle is composed of an upper ellipsoid particle and a lower ellipsoid particle, and the centers of the two ellipsoid particles are located on the same vertical line; The particle placement device also includes an angle adjustment device, the upper ellipsoid particle is fixed under the bottom plate of the downward extension beam, and the lower ellipsoid particle is fixed in the second U-shaped slot, and an angle adjustment device is provided under the second U-shaped slot; the angle adjustment device includes a worm gear mechanism, a rotating gear, an angle disk, a support plate, an outer ring, and a packaging shell; the support plate is a steel square plate, which is used to place particles, and a worm gear mechanism is provided at the bottom; the outer ring is sleeved on the outer edge of the rotating gear and is connected to the bottom of the support plate by bolts to form a whole, so as to keep the worm wheel and the gear in close contact at all times; the worm wheel is located above the rotating gear and is tightly meshed with it, and the worm wheel is driven to rotate by rotating the worm, thereby causing the support plate to rotate along the outer edge of the gear; the worm gear mechanism and the packaging shell surface of the rotating gear below are respectively provided with pointers and angle scales for indicating the inclination angle of the lower particle.

8. The inter-particle static and dynamic liquid bridge measurement system according to claim 1, characterized in that: The structures of the first U-shaped slot and the second U-shaped slot are the same; both are composed of a left U-shaped plate, a right U-shaped plate, a telescopic plate, and a gear. The left U-shaped plate and the right U-shaped plate are left-right symmetrical structures. The left U-shaped plate includes an inclined plate, a vertical plate and two horizontal rods. The inclined plate is located at the top, and the upper end of the vertical plate is connected to the inclined plate at an angle of 110°~130°; the bottom end of the vertical plate is vertically connected to the two horizontal rods, and the two horizontal rods are arranged in parallel on the upper and lower sides of the gear, and one of the horizontal rods is provided with sawtooth; the two horizontal rods of the left U-shaped plate and the right U-shaped plate are staggered and contact with the gear, wherein the horizontal rod with sawtooth is meshed with the gear, and the horizontal rod without sawtooth is located on the outside of the horizontal rod with sawtooth; the telescopic plate is a hollow movable structure, an elliptical hole is provided inside the telescopic plate, half of the ellipse is serrated, the gear is embedded in the telescopic plate and fixed to the bottom plate below by bolts, and the gear is respectively meshed with the sawtooth in the telescopic plate and with the sawtooth on the horizontal rods of the left U-shaped plate and the right U-shaped plate.

9. A method for measuring static and dynamic liquid bridges between particles using the static and dynamic liquid bridge measurement system between particles according to any one of claims 1 to 7, characterized in that The following steps are involved: Step 1: Build a static and dynamic measurement system for the liquid bridge between three particles; Step 2: Adjust the three particles to the set positions through the height and level adjustment devices in sequence; Step 3: The upper and lower spherical particles are brought closer together by fine-tuning the lifting device controlled by a computer, and a liquid drop is added to the apex of the spherical crown of the lower particle by using the injection needle of a micro-propellant pump. After the needle is retracted, the upper particle is lowered again until the liquid droplets overlap each other between the three particles to form a liquid bridge, and the initial reading of the lower extension beam and the initial reading of the microbalance are recorded by a laser rangefinder; Step 4: The upper and lower particles are gradually separated by fine-tuning the lifting device controlled by a computer, and the liquid bridge is stretched until it breaks. During this period, the laser rangefinder records the horizontal deflection of the bottom of the extension beam, and the high-speed camera records the morphology of the entire process of stretching and breaking the liquid bridge. Step 5: Calculate the horizontal suction of the liquid bridge indirectly through the horizontal deflection of the extended beam, and read the real-time size of the vertical suction of the liquid bridge through a microbalance; at the same time, according to the morphological records, apply image processing technology to invert the geometric characteristic parameters of the liquid bridge.

10. A method for measuring static and dynamic liquid bridges between particles using the static and dynamic liquid bridge measurement system between particles according to any one of claims 1 to 6 or 8, characterized in that The following steps are involved: Step 1: Build a static and dynamic measurement system for the liquid bridge between double ellipsoid particles; Step 2: The two ellipsoid particles are adjusted to the set positions by the height and level adjustment devices in turn, and the upper and lower ellipsoid particles are aligned by the high-speed camera; Step 3: The lower ellipsoid particle is clamped on the second U-shaped slot and fixed on the upper side of the support plate of the angle adjustment device by bolts; the angle adjustment device is turned to rotate the support plate to the set angle, and after the self-weight deformation of the beam is stable, the U-shaped slot is placed on the first microbalance so that it is in contact with the bottom surface of the beam, and the balance is adjusted to zero at the same time; Step 4: The upper and lower ellipsoid particles are brought closer together by fine-tuning the lifting device controlled by a computer, and a liquid drop is added to the top of the crown of the lower ellipsoid particle using the injection needle of a micro-propellant pump. After the needle is retracted, the upper ellipsoid particle is lowered again until the liquid drop overlaps the two ellipsoid particles to form a liquid bridge, and the initial reading of the first microbalance is recorded at this time; Step 5: The upper and lower ellipsoid particles are gradually separated by fine-tuning the lifting device controlled by a computer; the geometric morphology of the entire process of liquid bridge stretching and breaking is recorded by a high-speed camera; and the magnitude of the liquid bridge suction is read by the first microbalance.

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