Solidified soil erosion test system with flow field control and interface dynamic compensation function

Abstract

The application discloses a solidified soil erosion test system with flow field control and interface dynamic compensation functions, which comprises an erosion reaction cylinder, a rotating flow creating unit, a sample mounting unit, an interface dynamic compensation unit, a flow field stability regulation unit and a control unit. A closed circulation erosion space is formed in the erosion reaction cylinder, and a sample mounting interface is arranged on the side wall. The rotating flow creating unit forms a circulating shear flow field in the erosion reaction cylinder. The sample mounting unit is used for making the exposed end surface of the solidified soil sample flush with the inner wall to form an erosion interface. The interface dynamic compensation unit compensates according to the loss of the sample material through a pushing mechanism, so that the spatial position of the erosion interface remains constant. The flow field stability regulation unit is used for realizing fluid circulation and target flow speed control. The control unit obtains the interface topography change based on an image acquisition module, and outputs a control signal to link and adjust the pushing mechanism and the rotating flow creating unit, so as to realize the cooperative control of the flow field and the interface state.

Description

Technical Field

[0001] This application relates to the fields of geotechnical testing and hydraulic engineering testing technology, specifically to a solidified soil erosion testing system with flow field control and interface dynamic compensation functions. Background Technology

[0002] Solidified soil, an engineering material formed by incorporating a solidifying agent and undergoing a hydration reaction, has been widely used in roadbed engineering, coastal protection, and underwater foundation reinforcement due to its excellent integrity, compressive strength, and resource reusability. In actual service environments, solidified soil structures are often exposed to long-term water erosion. Its erosion resistance and the erosion characteristics of the material under continuous water shear conditions directly affect the safety and durability of the engineering structure. Therefore, quantitative and repeatable experimental research on the erosion resistance of solidified soil is of great significance.

[0003] Existing solidified soil scouring tests mostly employ water tank or circulating waterway test devices, which use water pumps to drive water flow at a certain velocity to scour the surface of the solidified soil sample. However, these test devices generally suffer from problems such as large volume, limited flow field control precision, and uneven flow velocity distribution on the wall, making it difficult to achieve stable high-velocity scouring conditions within a limited space. Furthermore, the sample surface is prone to positional changes due to material erosion during the scouring process, causing the scouring interface to continuously shift. This results in inconsistent scouring conditions at different time points, thus affecting the accurate measurement and comparability of key parameters such as scouring rate and starting flow velocity. Summary of the Invention

[0004] The purpose of at least one specific embodiment of the present invention is to overcome the deficiencies of the prior art and provide a solidified soil erosion test system with flow field control and interface dynamic compensation functions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A solidified soil erosion testing system with flow field control and interface dynamic compensation functions includes: The flushing reaction cylinder has a closed-loop flushing space inside, and the side wall is provided with an installation interface for sample exposure. The rotary flow generation unit includes a drive motor and a rotary impeller assembly connected thereto, wherein the rotary impeller assembly forms a circulating shear flow field within the scouring reaction cylinder; The sample mounting unit includes a sample tube, which is mounted at the mounting interface and forms a continuous flush scouring interface between the exposed end face of the sample and the inner wall of the scouring reaction cylinder. The interface dynamic compensation unit includes a propulsion mechanism that slides with the sample cylinder. The propulsion mechanism compensates the sample based on the amount of material loss on the sample surface during the scouring process, so that the scouring interface maintains a preset spatial position during the scouring process. A flow field stabilization and control unit is used to maintain continuous circulation of fluid within the scouring reaction cylinder and to achieve target flow velocity range control. The control unit includes an image acquisition module and a control module, wherein the image acquisition module is used to acquire the morphological changes of the scouring interface; The control module extracts the normal thickness change of the scouring interface based on the interface morphology change information obtained by the image acquisition module, and generates the corresponding propulsion compensation displacement. The control unit controls the propulsion mechanism to compensate and propel the sample, keeping the scouring interface within a preset spatial position range during the scouring process. At the same time, it coordinates and adjusts the rotating flow-generating unit and the flow field stabilization control unit to keep the local shear flow field distribution in the area where the scouring interface is located stable and to suppress the disturbance of the flow field distribution caused by the change in the position of the scouring interface, thereby forming a coupled constraint relationship between the position of the scouring interface and the flow field distribution.

[0006] Furthermore, the solidified soil scour testing system also includes a flow field homogenization structure, which is set in the radial gap region between the outer periphery of the rotating impeller assembly and the inner wall of the scour reaction cylinder, so as to form a uniform shear flow field at the scour interface with a height velocity gradient less than a preset threshold.

[0007] Furthermore, the rotating impeller assembly includes an inner shaft and an outer shaft, an impeller fixedly mounted on the surface of the outer shaft, the image acquisition module mounted on the inner shaft, the outer shaft sleeved on the outside of the inner shaft and connected to the drive motor, and the outer shaft is provided with a perspective opening coaxially aligned with the shooting line of the image acquisition module.

[0008] Furthermore, the flow field homogenization structure is composed of a geometrically constrained region formed by matching the diameter and number of the impellers; Wherein, when the diameter of the impeller and the inner diameter of the scouring reaction cylinder meet a preset ratio and the rotating impeller assembly is a multi-bladed uniformly distributed structure, the flow field homogenization structure can weaken the superposition effect of axial velocity attenuation and wall shear gradient at the scouring interface, so that the flow velocity gradient in the height direction of the scouring interface area is reduced to below a preset threshold.

[0009] Furthermore, the shooting frequency of the image acquisition module is synchronously adjusted according to the rotation frequency of the outer axis.

[0010] Furthermore, the impeller extends along the central axis of the scouring reaction cylinder within the cylinder, and there are multiple sample cylinders arranged at intervals along the central axis of the scouring reaction cylinder, so that each sample cylinder corresponds to a flow field region at a different axial position within the scouring reaction cylinder.

[0011] Furthermore, the preset ratio is between 0.6 and 0.85.

[0012] Furthermore, multiple sample cylinders are disposed in the axial central region of the impeller.

[0013] Furthermore, the flow field stabilization control unit includes a circulation pipe, a circulation pump, a flow regulating valve, and a filter assembly installed on the circulation pipe. One end of the circulation pipe is connected to the inlet on the flushing reaction cylinder, and the other end is connected to the outlet on the flushing reaction cylinder. The circulation pump and the flushing reaction cylinder form a closed-loop circulation channel. The flow regulating valve is adapted to regulate the flow rate of the fluid entering the flushing reaction cylinder to control the target flow velocity range.

[0014] Furthermore, a proportional mapping relationship is established between the amount of propulsion displacement when the interface dynamic compensation unit compensates the sample and the amount of change in the erosion interface morphology obtained by the image acquisition module, and the proportional mapping relationship is determined based on a preset calibration curve.

[0015] Furthermore, the control unit performs time series analysis on the changes in the morphology of the scouring interface and dynamically corrects the control signal output by the propulsion mechanism to suppress interface position oscillations caused by instantaneous scouring fluctuations.

[0016] Furthermore, the scouring reaction cylinder includes a horizontal placement state and a vertical placement state; wherein, in the horizontal placement state, the scouring reaction cylinder is used to simulate the scouring condition of plastic solidified soil under low self-weight conditions, and in the vertical placement state, the scouring reaction cylinder is used to simulate the scouring condition of high-strength final solidified soil.

[0017] Furthermore, the flushing reaction cylinder is made of a transparent material.

[0018] Compared with the prior art, the beneficial effects of this application are as follows: 1. By constructing a controllable rotating shear flow field in a closed scouring reaction cylinder and combining interface dynamic compensation and closed-loop control mechanism, this invention achieves synchronous and stable control of flow field conditions and scouring interface position during the solidified soil scouring test, thereby effectively solving the problems of uneven flow field and easy deviation of sample interface in existing test devices, which leads to inconsistent test results.

[0019] 2. This invention forms a stable and controllable circulating flow field in a small volume space through a rotating flow-generating unit, which improves the upper limit of flow velocity and the uniformity of flow field per unit space. This enables the experimental device to simulate a high-velocity scouring environment under smaller scale conditions, thereby improving the space utilization efficiency and working condition simulation capability of the experimental device. At the same time, the circulating flow rate is adjusted in a closed loop through the flow field stabilization control unit, so that the fluid in the scouring reaction tube remains in a continuous and stable state, thereby improving the repeatability and comparability of scouring conditions.

[0020] 3. This invention uses an interface dynamic compensation unit to compensate for material loss on the sample surface in real time during the scouring process, so that the scouring interface is always kept in a preset spatial position, effectively avoiding local flow field changes caused by interface retreat or instability, fundamentally ensuring the consistency of scouring conditions at different time stages, and improving the measurement accuracy of key parameters such as scouring rate and starting flow velocity. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the equipment structure of the solidified soil erosion test system of this application.

[0023] Figure 2 This is a schematic diagram of the control principle of this application.

[0024] Figure 3 for Figure 1 A partial structural diagram.

[0025] Figure 4 This is a schematic diagram of the installation of the sample tube on the scouring reaction tube in this application.

[0026] Figure 5 This is a schematic diagram showing the cooperation between the sample cylinder and the propulsion mechanism in this application.

[0027] Figure 6 This is a schematic diagram of the rotating impeller assembly of this application.

[0028] Figure 7 This is a diagram showing the planar velocity vector distribution characteristics of a six-bladed impeller with a diameter of 120 mm within the scouring reactor at a rotational speed of 640 rpm.

[0029] Figure 8This is a diagram showing the planar velocity vector distribution characteristics of a 120 mm diameter four-bladed impeller within a scouring reactor at a rotational speed of 640 rpm.

[0030] Figure 9 This is a diagram showing the planar velocity vector distribution characteristics of a two-bladed impeller with a diameter of 120 mm within the scouring reactor at a rotational speed of 640 rpm.

[0031] Figure 10 This is a diagram showing the planar velocity vector distribution characteristics of a six-bladed impeller with a diameter of 100 mm within the scouring reactor at a rotational speed of 640 rpm.

[0032] Figure 11 This is a diagram showing the planar velocity vector distribution characteristics of a 100 mm diameter four-bladed impeller within a scouring reactor at a rotational speed of 640 rpm.

[0033] Figure 12 This is a diagram showing the planar velocity vector distribution characteristics of a two-bladed impeller with a diameter of 100 mm within the scouring reactor at a rotational speed of 640 rpm.

[0034] Figure 13 This is a diagram showing the planar velocity vector distribution characteristics of a six-bladed impeller with a diameter of 80 mm within the scouring reactor at a rotational speed of 640 rpm.

[0035] Figure 14 This is a diagram showing the planar velocity vector distribution characteristics of a four-bladed impeller with a diameter of 80 mm within the scouring reactor at a rotational speed of 640 rpm.

[0036] Figure 15 This is a diagram showing the planar velocity vector distribution characteristics of a two-bladed impeller with a diameter of 80 mm within the scouring reactor at a rotational speed of 640 rpm.

[0037] Reference numerals: 1. Flushing reaction cylinder; 11. Flushing space; 12. Mounting interface; 13. Vent; 14. Inlet; 15. Outlet; 2. Rotary flow generation unit; 21. Drive motor; 22. Rotary impeller assembly; 221. Inner shaft; 222. Outer shaft; 223. Impeller; 224. Perspective opening; 3. Sample mounting unit; 31. Sample cylinder; 32. Solidified soil sample; 33. Flushing interface; 34. Piston plate; 4. Interface dynamics Compensation unit; 41. Propulsion mechanism; 411. Screw; 412. Nut seat; 413. Drive component; 414. Guide sleeve; 415. Support rod; 5. Flow field stabilization control unit; 51. Circulation pipe; 52. Circulation pump; 53. Flow regulating valve; 54. Filter assembly; 55. Flow meter; 56. Water supply interface; 6. Control unit; 61. Image acquisition module; 62. Control module; 71. Base; 72. Fixing plate; 73. Cage. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] like Figures 1 to 4 As shown, the solidified soil scour test system with flow field control and interface dynamic compensation functions mainly includes a scour reaction cylinder 1, a rotating flow generation unit 2, a sample installation unit 3, an interface dynamic compensation unit 4, a flow field stability control unit 5, and a control unit 6. The units work together to achieve continuous scour testing of solidified soil under controlled flow field conditions.

[0040] Specifically, the flushing reaction cylinder 1 is a hollow and transparent cylindrical structure, with a closed circulating flushing space 11 inside, used to contain the circulating fluid and create a flushing environment. Preferably, the flushing reaction cylinder 1 is made of transparent acrylic material, which ensures structural strength and facilitates external observation.

[0041] The sidewall of the scouring reaction cylinder 1 is provided with multiple axially distributed mounting interfaces 12. Each mounting interface 12 is used to install the sample cylinder 31, so that the solidified soil sample can be partially exposed in the scouring space 11 and participate in the scouring process. The upper part of the scouring reaction cylinder 1 is provided with an exhaust hole 13 to remove internal air bubbles and prevent gas from interfering with the stability of the flow field. At the same time, its sidewall is also provided with a water inlet 14 and a water outlet 15 for connecting with the flow field stabilization control unit 5 to form a circulation channel.

[0042] The rotating flow-generating unit 2 is located inside the flushing reaction cylinder 1, and includes a drive motor 21 and a rotating impeller assembly 22 connected to the drive motor 21.

[0043] Reference Figure 3 and Figure 6 The rotating impeller assembly 22 includes an inner shaft 221 and an outer shaft 222. The outer shaft 222 is a hollow sleeve structure, sleeved on the outside of the inner shaft 221 and connected to the drive motor 21 for transmission, thereby rotating around the central axis of the scouring reaction cylinder 1 under the drive of the motor. Multiple impellers 223 are fixedly mounted on the outer circumference of the outer shaft 222. The impellers 223 are preferably multi-bladed with evenly distributed blades, such as four-bladed or six-bladed impellers, to improve the uniformity of the flow field. Furthermore, the outer shaft 222 is provided with a viewing opening 224, which is coaxially arranged with the image acquisition direction to ensure that an unobstructed observation window can be periodically provided during rotation.

[0044] Furthermore, the inner shaft 221 is a fixed structure, on which an image acquisition module 61 is mounted. The image acquisition module 61 is preferably a high-speed camera, with its lens facing the exposed interface of the sample in the sample mounting unit 3, thereby enabling real-time observation of the scouring interface. Through the coaxial sleeve structure of the inner shaft 221 and the outer shaft 222, the structural decoupling of the rotation flow generation system and the image acquisition system is achieved, effectively avoiding the influence of rotational disturbances on the stability of image acquisition.

[0045] Furthermore, the shooting frequency of the image acquisition module 61 is synchronously adjusted according to the rotation frequency of the outer shaft 222, so that it performs image acquisition within the time window when the impeller 223 has the least obstruction, thereby ensuring the clarity and continuity of the acquired image.

[0046] In this embodiment, in order to improve the stability of the flushing reaction cylinder 1 and the rotating flow generation unit 2, the bottom of the flushing reaction cylinder 1 is equipped with a base 71, and the top of the flushing reaction cylinder 1 is equipped with a fixing plate 72. The base 71 and the fixing plate 72 are fixedly connected by a retainer 73. One end of the inner shaft 221 extends into the inner cavity of the flushing reaction cylinder 1 and is fixedly connected to the bottom of the flushing reaction cylinder 1. The drive motor 21 is fixedly installed on the fixing plate 72. One end of the outer shaft 222 is connected to the drive motor 21 for transmission, and the other end extends into the flushing reaction cylinder 1 and is rotatably connected to the bottom of the flushing reaction cylinder 1 through a bearing seat.

[0047] To verify the influence of the structural parameters of impeller 223 on the uniformity of the flow field on the inner wall of the scouring reaction cylinder 1, this invention uses a combination of numerical simulation and physical experiments to compare and analyze the flow field distribution characteristics under different blade numbers (two blades, four blades, six blades), different impeller diameters (80mm, 100mm, 120mm), and different rotational speeds.

[0048] The results show that when the impeller diameter is 80 mm, the velocity distribution along the height direction on the wall of the scouring reactor 1 exhibits obvious non-uniform characteristics, specifically, the velocity is lower in the middle and higher at both ends, and the increase in the number of blades has a limited effect on improving the uniformity of the flow field. When the impeller diameter increases to 100 mm, the overall velocity level on the wall increases, the velocity distribution tends to be gentler, and the uniformity of the flow field is significantly improved under the four-blade and six-blade impeller structures. When the impeller diameter is further increased to 120 mm, the velocity difference at different height positions on the wall decreases significantly, the velocity distribution tends to be uniform, and it exhibits stable shear flow field characteristics.

[0049] Under the condition of a fixed impeller diameter, the change in rotational speed mainly affects the amplitude of the wall velocity and has little effect on the velocity distribution pattern. However, increasing the number of blades can improve the overall velocity level and improve local uniformity to a certain extent. Among them, four-bladed and six-bladed impeller structures exhibit better flow field stability.

[0050] Reference Figures 7-15In this application, the impeller 223 is set to rotate at 640 rpm, and the inner diameter of the scouring reaction chamber 1 is 150 mm. The planar velocity vector distribution characteristics at a wall height Z=15 cm of the scouring reaction chamber 1 are analyzed by comparing different impeller diameters (D=80 / 100 / 120 mm) and the number of impeller blades (N=2 / 4 / 6). The redder the region, the faster the velocity, and the red region is more uniformly distributed with a six-bladed impeller configuration. Although the overall velocity decreases when the diameter is reduced to 100 mm and 80 mm, the six-bladed impeller can still provide a uniform velocity distribution.

[0051] The results show that increasing the impeller diameter leads to an increase in flow velocity, and increasing the number of impeller blades significantly improves the uniformity of fluid velocity distribution, with the highest velocity occurring at the impeller tip. At a rotational speed of 640 rpm, a six-bladed impeller with a diameter of 120 mm creates a high velocity level and a small velocity gradient in the wall flow field within the reactor, exhibiting good flow field uniformity. When the impeller diameter decreases to 100 mm and 80 mm, although the overall velocity level decreases, under the same diameter conditions, the six-bladed impeller structure still effectively reduces the degree of velocity distribution non-uniformity compared to structures with fewer blades. These results indicate that the impeller diameter has a dominant influence on the velocity level, while the number of blades has a moderating effect on flow field uniformity.

[0052] The numerical simulation results and the physical test results are consistent in terms of velocity distribution. Both show that the impeller diameter has a greater impact on the uniformity of the wall velocity than the number of blades and the rotational speed. Furthermore, as the impeller diameter increases, the velocity distribution of the wall shear flow field tends to be more uniform, exhibiting a relatively uniform flow field characteristic when the working condition is close to 120 mm.

[0053] Further analysis revealed that in the area near the bottom of the wall of the scouring reaction cylinder 1, at a wall height of Z=0.1cm, the flow velocity exhibited a significant radial non-uniform distribution. Furthermore, the peak flow velocity was higher at the end of the impeller 223, while the flow velocity was lower near the wall, indicating that the scouring effect in this area was uneven and unsuitable as a stable sample arrangement area.

[0054] In summary, the matching relationship between the diameter of impeller 223 and the number of blades of impeller 223 has a decisive influence on the uniformity of the shear flow field on the inner wall of the scouring reaction cylinder 1. Among them, the impeller diameter is the dominant influencing factor, and the number of blades is the auxiliary adjustment factor. Based on the above experimental results and numerical simulation analysis, it is determined that when the ratio of impeller diameter to inner diameter of scouring reaction cylinder is in the range of 0.6 to 0.85 and the impeller adopts a multi-blade uniformly distributed structure, a shear flow field with uniform velocity distribution and small axial velocity gradient can be formed in the scouring interface region. This provides a basis for the selection of parameters for the flow field homogenization structure in this invention.

[0055] Furthermore, the sample mounting unit 3 includes multiple sample cylinders 31. The sample cylinders 31 are mounted at the mounting interface 12 on the side wall of the scouring reaction cylinder 1 and connected to the scouring reaction cylinder 1 through a sealing structure (e.g., a sealing ring). One end of the sample cylinder 31 faces the scouring reaction cylinder 1. Each sample cylinder 31 is used to hold a solidified soil sample 32. The inner end of the solidified soil sample 32 is exposed inside the scouring reaction cylinder 1 and is flush with the inner wall of the scouring reaction cylinder 1, thereby forming a continuous scouring interface 33. In addition, a piston plate 34 can be installed inside the sample cylinder 31. When the piston plate 34 moves inside the sample cylinder 31, it can push the solidified soil sample 32 inside the sample cylinder 31 out from the scouring interface 33.

[0056] Preferably, the sample tube 31 is a detachable structure, which facilitates sample replacement and maintenance. Multiple sample tubes 31 are arranged at intervals along the central axis of the scouring reaction tube 1, thereby corresponding to the flow field regions at different axial positions.

[0057] More preferably, multiple sample cylinders 31 are arranged in the axial middle region of the impeller 223 to avoid the strong disturbance zone at the impeller end and the influence zone of the wall boundary layer, thereby ensuring the stability and uniformity of the flow field in the test area.

[0058] In this embodiment, the number of perspective openings 224 corresponds to the number of image acquisition modules 61 and sample cylinders 31. Each perspective opening 224 corresponds circumferentially to the corresponding sample cylinder 31 and is aligned with the line of sight of the image acquisition module 61. This creates an unobstructed observation window periodically during the rotation of the rotating impeller assembly 22, enabling the image acquisition module 61 to acquire stable and continuous images of the scouring interface 33 corresponding to each sample. This structural design not only ensures the synchronization and consistency of image acquisition under multi-sample conditions but also effectively avoids obstruction of the observation path by the rotating impeller assembly 22, improving the accuracy of image recognition and the reliability of data acquisition.

[0059] Additionally, refer to Figure 5 The interface dynamic compensation unit 4 is located at the end of the sample cylinder 31 away from the scouring reaction cylinder 1. It includes a propulsion mechanism 41, which cooperates with the piston plate 34 inside the sample cylinder 31 to axially propel the solidified soil sample 32. The propulsion mechanism 41 is preferably a spiral propulsion structure or an electric push rod structure, which can precisely control the propulsion displacement. During the scouring process, as the sample surface material is continuously eroded by the water flow, without compensation, the scouring interface 33 will gradually retreat, thereby changing the local flow field conditions. Therefore, this invention uses the propulsion mechanism 41 to provide real-time compensation for the solidified soil sample 32, ensuring that the scouring interface 33 remains at a preset spatial position, thus guaranteeing the consistency of the scouring conditions.

[0060] When the propulsion mechanism 41 adopts a helical propulsion structure, it is integrally located at the end of the sample cylinder 31 away from the scouring reaction cylinder 1 and arranged along the axial direction of the sample cylinder 31. Its specific structure includes a screw 411, a nut seat 412, a drive component 413 (such as a motor with a reducer), and a guide sleeve 414. The screw 411 extends axially, with one end connected to the drive component 413, achieving rotational motion around its own axis under the action of the drive component 413. The nut seat 412 is connected to the screw 411 via a threaded joint. A support rod 415 on one side of the nut seat 412 extends to one side of the piston plate 34, converting the rotational motion of the screw 411 into the rotational motion of the nut seat 412. 12. Axial linear propulsion motion; The guide sleeve 414 is disposed on the outside of the nut seat 412 and is arranged in conjunction with the nut seat 412 to guide the axial movement direction of the nut seat 412 and provide circumferential anti-torsional constraint to prevent the nut seat 412 from rotating with the screw 411, thereby ensuring that the rotational motion of the screw 411 can be stably and effectively converted into the axial linear motion of the nut seat 412, improving the stability and transmission accuracy of the propulsion process; Through the synergistic effect of the above structures, the propulsion mechanism 41 can achieve continuous, controllable and high-precision adjustment of the sample propulsion displacement during the scouring test, thereby meeting the stability and repeatability requirements of dynamic compensation of the scouring interface.

[0061] Furthermore, a proportional mapping relationship is established between the propulsion displacement of the propulsion mechanism 41 and the change in the morphology of the scouring interface acquired by the image acquisition module 61. This proportional mapping relationship is obtained through pre-calibration experiments. During actual operation, the control unit 6 performs morphological analysis on the scouring interface 33 based on the image recognition results to extract the thickness change Δh(t) in its normal direction, and calculates the corresponding propulsion compensation displacement Δs(t) according to the proportional mapping relationship, where the following relationship is satisfied: .

[0062] Wherein, Δs(t) represents the amount of compensation displacement required by the propulsion mechanism 41 at the current moment, Δh(t) represents the amount of thickness loss of the scouring interface along the normal direction per unit time, and K is the proportional mapping coefficient. The proportional mapping coefficient K is determined by pre-calibration test under typical flow velocity conditions and typical scouring conditions, and is used to characterize the correspondence between the interface change obtained by image recognition and the actual material erosion displacement.

[0063] Furthermore, to reduce the impact of measurement errors caused by local eddy currents and instantaneous flow field fluctuations on control accuracy during the scouring process, control unit 6 performs time-series smoothing on Δh(t) to weaken the interference of high-frequency fluctuation components. In addition, to further suppress the scouring interface position oscillation caused by transient disturbances and control response lag during the scouring process, control unit 6 dynamically weights and corrects the propulsion control output of propulsion mechanism 41 to obtain the corrected propulsion displacement Δs′(t), which satisfies the following relationship: , where α is a weighting coefficient with a value range of 0 < α ≤ 1, used to adjust the weight ratio between the compensation amount at the current moment and the compensation amount at the historical moment, so as to achieve a balance between control response speed and system stability, thereby effectively suppressing the oscillation of the scouring interface position caused by instantaneous scouring fluctuations and improving the smoothness of the interface dynamic compensation process.

[0064] In this embodiment, the flow field stabilization and control unit 5 is used to maintain the continuous circulation and flow rate control of the fluid in the flushing reaction cylinder 1. Specifically, it includes a circulation pipe 51, a circulation pump 52, a flow regulating valve 53, and a filter assembly 54. One end of the circulation pipe 51 is connected to the inlet 14 of the flushing reaction cylinder 1, and the other end is connected to the outlet 15, thus forming a closed-loop circulation channel. The circulation pump 52 drives the fluid circulation, and the flow regulating valve 53 regulates the fluid flow rate, thereby achieving control of the target flow rate range. The filter assembly 54 is installed in the circulation pipe to filter solid particles that fall off during the flushing process, preventing particle accumulation from interfering with the flow field structure and ensuring the clarity of image acquisition.

[0065] Furthermore, the flow field stabilization control unit 5 also includes a flow meter 55 and a water supply interface 56 installed on the circulation pipe 51. The flow meter 55 is used to detect the flow parameters of the circulating fluid in real time and feed the detection signal back to the control unit 6 to realize the closed-loop control of the flow regulating valve 53, thereby improving the flow field control accuracy. The water supply interface 56 is used to replenish the circulating fluid during system operation to maintain the stability of the fluid volume and pressure in the flushing reaction cylinder 1. In this embodiment, the fluid in the circulation pipe 51 can be tap water.

[0066] Furthermore, a radial gap region is formed between the outer periphery of the rotating impeller assembly 22 and the inner wall of the scouring reaction cylinder 1, which constitutes a flow field homogenization structure. This flow field homogenization structure is not an independent component, but a geometrically constrained region formed by matching the diameter of the impeller 223 with the number of blades. When the diameter of the impeller 223 and the inner diameter of the scouring reaction cylinder 1 satisfy a ratio of 0.6 to 0.85, and the impeller 223 has a multi-bladed uniformly distributed structure, this structure can effectively weaken the axial velocity attenuation and the superposition effect of the wall shear gradient at the scouring interface 33, significantly reducing the velocity gradient along the height direction in the region of the scouring interface 33, thereby forming a stable and uniform shear flow field.

[0067] In practical implementation, this system can select different installation postures according to different test requirements. Preferably, the scouring reaction cylinder 1 can switch between a horizontal and a vertical placement. In the horizontal placement state, it is suitable for simulating the scouring conditions of plastic solidified soil under low self-weight conditions, at which time the solidified soil sample 32 is not prone to collapse; in the vertical placement state, it can simulate the scouring conditions of high-strength final solidified soil sample 32 and can obtain a higher upper limit of flow velocity, thereby meeting the testing requirements of solidified soil at different stages.

[0068] The working process of this invention is as follows: First, the prepared solidified soil sample 32 is filled into the sample tube 31, and the sample tube 31 is fixedly installed on the side wall of the scouring reaction tube 1 through the installation interface 12, so that the exposed end face of the solidified soil sample 32 is flush with the inner wall of the scouring reaction tube 1, thereby forming a continuous scouring interface 33; then, fluid is injected into the scouring reaction tube 1 through the flow field stabilization control unit 5, and a closed circulating flow system is established under the action of the circulation pipeline; the drive motor 21 is started to drive the rotating impeller assembly 22 to rotate, so that a stable circulating shear flow field is formed in the scouring reaction tube 1, thereby applying a controllable hydrodynamic effect to the scouring interface 33.

[0069] During the scouring process, the image acquisition module 61 continuously acquires images of the scouring interface 33 at a preset sampling frequency and transmits the image data to the control unit 6 in real time. The control module 62 of the control unit 6 performs interface feature recognition processing on the image data to extract the boundary contour information of the scouring interface 33 and further calculates the thickness change Δh(t) of the interface in the normal direction, thereby characterizing the amount of scouring loss of the solidified soil material per unit time.

[0070] The control unit 6 converts Δh(t) into the corresponding propulsion compensation displacement based on the pre-calibrated proportional mapping relationship, and outputs a control signal to the propulsion mechanism 41, so that the propulsion mechanism 41 drives the sample to perform compensation propulsion in the axial direction, so that the scouring interface 33 is always kept in the preset spatial position, thereby realizing the dynamic and stable control of the scouring interface.

[0071] Meanwhile, the control unit 6 performs linkage control on the drive motor 21 and the flow regulating valve 53 based on the same control strategy. By adjusting the impeller speed and circulation flow, the intensity of the scouring flow field can be adjusted in real time to meet the requirements of scouring tests under different flow velocity conditions. Under the synergistic effect of propulsion compensation and flow field adjustment, the scouring interface 33 is always in a stable and controlled shear flow field region.

[0072] Finally, by recording the relationship between the change in interface thickness and time under different flow rate settings, the flow rate-scouring rate correspondence curve was obtained, which was used to characterize the scouring resistance of the solidified soil material.

[0073] In summary, this invention constructs a controllable rotating shear flow field within the closed scouring reaction cylinder 1, and combines an interface dynamic compensation mechanism with a closed-loop control mechanism to achieve synchronous and stable control of the flow field conditions and the position of the scouring interface during the solidified soil scouring test. This effectively solves the problems of uneven flow field distribution and easy deviation of the sample interface in existing test devices, which leads to poor repeatability of test results.

[0074] Meanwhile, the present invention forms an efficient circulating flow field in a small space through a rotating flow-generating unit, which improves the upper limit of flow velocity and the uniformity of flow field in a unit space, enabling the device to simulate a high flow velocity scouring environment in a compact structure, thereby improving the space utilization efficiency and working condition simulation capability of the test device; and through the flow field stabilization control unit, the circulating flow rate is adjusted in a closed loop to keep the fluid in the scouring reaction tube in a continuous and stable state, further improving the repeatability and comparability of scouring conditions.

[0075] In addition, the interface dynamic compensation unit compensates for the material loss on the sample surface in real time during the scouring process, so that the scouring interface is always kept in the preset spatial position, effectively avoiding local flow field changes caused by interface retreat, thereby ensuring the consistency of scouring conditions at different time stages and improving the measurement accuracy and reliability of key parameters such as scouring rate and starting flow velocity.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solidified soil erosion testing system with flow field control and interface dynamic compensation functions, characterized in that, include: The flushing reaction cylinder has a closed-loop flushing space inside, and the side wall is provided with an installation interface for sample exposure. The rotary flow generation unit includes a drive motor and a rotary impeller assembly connected thereto, wherein the rotary impeller assembly forms a circulating shear flow field within the scouring reaction cylinder; The sample mounting unit includes a sample tube, which is mounted at the mounting interface and forms a continuous flush scouring interface between the exposed end face of the sample and the inner wall of the scouring reaction cylinder. The interface dynamic compensation unit includes a propulsion mechanism that slides with the sample cylinder. The propulsion mechanism compensates the sample based on the amount of material loss on the sample surface during the scouring process, so that the scouring interface maintains a preset spatial position during the scouring process. A flow field stabilization and control unit is used to maintain continuous circulation of fluid within the scouring reaction cylinder and to achieve target flow velocity range control. The control unit includes an image acquisition module and a control module, wherein the image acquisition module is used to acquire the morphological changes of the scouring interface; The control module extracts the normal thickness change of the scouring interface based on the interface morphology change information obtained by the image acquisition module, and generates the corresponding propulsion compensation displacement. The control unit controls the propulsion mechanism to compensate and propel the sample, keeping the scouring interface within a preset spatial position range during the scouring process. At the same time, it coordinates and adjusts the rotating flow-generating unit and the flow field stabilization control unit to keep the local shear flow field distribution in the area where the scouring interface is located stable and to suppress the disturbance of the flow field distribution caused by the change in the position of the scouring interface, thereby forming a coupled constraint relationship between the position of the scouring interface and the flow field distribution.

2. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, It also includes a flow field homogenization structure, which is disposed in the radial gap region between the outer periphery of the rotating impeller assembly and the inner wall of the scouring reaction cylinder, so as to form a uniform shear flow field at the scouring interface with a height velocity gradient of less than a preset threshold.

3. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 2, characterized in that, The rotating impeller assembly includes an inner shaft and an outer shaft, an impeller fixedly mounted on the surface of the outer shaft, the image acquisition module mounted on the inner shaft, the outer shaft sleeved outside the inner shaft and connected to the drive motor, and the outer shaft having a perspective opening coaxially aligned with the shooting line of the image acquisition module.

4. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 3, characterized in that, The flow field homogenization structure is composed of a geometrically constrained region formed by matching the diameter and number of the impellers; Wherein, when the diameter of the impeller and the inner diameter of the scouring reaction cylinder meet a preset ratio and the rotating impeller assembly is a multi-bladed uniformly distributed structure, the flow field homogenization structure can weaken the superposition effect of axial velocity attenuation and wall shear gradient at the scouring interface, so that the flow velocity gradient in the height direction of the scouring interface area is reduced to below a preset threshold.

5. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 3, characterized in that, The shooting frequency of the image acquisition module is synchronously adjusted according to the rotation frequency of the outer axis.

6. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 3, characterized in that, The impeller extends along the central axis of the scouring reaction cylinder inside the scouring reaction cylinder. There are multiple sample cylinders, and the multiple sample cylinders are arranged at intervals along the central axis of the scouring reaction cylinder so that each sample cylinder corresponds to a flow field region at a different axial position inside the scouring reaction cylinder.

7. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 4, characterized in that, The preset ratio is between 0.6 and 0.

85.

8. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 6, characterized in that, Multiple sample cylinders are disposed in the axial central region of the impeller.

9. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, The flow field stabilization control unit includes a circulation pipe, a circulation pump, a flow regulating valve, and a filter assembly installed on the circulation pipe. One end of the circulation pipe is connected to the inlet on the flushing reaction cylinder, and the other end is connected to the outlet on the flushing reaction cylinder. The circulation pump and the flushing reaction cylinder form a closed-loop circulation channel. The flow regulating valve is adapted to regulate the flow rate of the fluid entering the flushing reaction cylinder in order to control the target flow velocity range.

10. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, The interface dynamic compensation unit establishes a proportional mapping relationship between the amount of propulsion displacement when compensating the sample and the amount of change in the erosion interface morphology obtained by the image acquisition module, and the proportional mapping relationship is determined based on a preset calibration curve.

11. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, The control unit performs time-series analysis on the changes in the morphology of the scouring interface and dynamically corrects the control signal output by the propulsion mechanism to suppress interface position oscillations caused by instantaneous scouring fluctuations.

12. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, The scouring reaction cylinder includes a horizontal placement state and a vertical placement state; wherein, in the horizontal placement state, the scouring reaction cylinder is used to simulate the scouring condition of plastic solidified soil under low self-weight conditions, and in the vertical placement state, the scouring reaction cylinder is used to simulate the scouring condition of high-strength final solidified soil.

13. The solidified soil erosion testing system with flow field control and interface dynamic compensation functions according to claim 1, characterized in that, The flushing reaction cylinder is made of transparent material.

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