A Physical Model Test of Flood Discharge Fog and Rain: A Fog Rain Simulation Device and Test Method

Abstract

This invention belongs to the field of rock mass engineering testing devices, and provides a physical model test device and method for flood discharge fog and rain simulation, including: a model box, a water supply system, a fog and rain simulation system, and a groundwater simulation system. The model box consists of a sedimentation tank and a test chamber. The water supply system mainly consists of an inlet pipe, a storage tank, a delivery pipe, a variable frequency self-priming booster pump, a flow meter, a check valve, a bend joint, and a main water pipe. The fog and rain simulation system mainly consists of a frame, a servo motor, steel strands, fixed supports, anchors, a top water pipe, a tee joint, a bend joint, and nozzles. The groundwater simulation system includes a front water level regulating tank and a rear water level regulating tank. This invention realizes the influence of fog and rain zoning and the coupling effect of fog and rain with groundwater level on fractured rock slopes, which is of great significance for the study of the stability of high dam fractured rock slopes under flood discharge fog during the construction and operation of hydropower projects.

Description

Technical Field

[0001] This invention belongs to the field of physical model test devices for flood discharge fog and rain, and provides a fogging rain simulation device and test method for physical model test of flood discharge fog and rain. Background Technology

[0002] Flood discharge atomization refers to the dense fog-rain phenomenon formed by the atomized flow of water during peak flood discharge at water conservancy projects. This fog-rain often reaches intensities exceeding those of torrential rainstorms. This atomized rain infiltrates into fractured rock slopes, altering the internal hydrological environment and directly threatening the deformation and stability of reservoir bank rock slopes. The stability problem of fractured rock slopes caused by flood discharge atomization is a major challenge facing hydropower projects in southwestern my country. Therefore, studying the stability of fractured rock slopes under the influence of atomized rain is of great significance for addressing environmental geological issues in hydropower project construction.

[0003] Slope model tests offer advantages such as diverse boundary conditions, ease of operation, and high reproducibility, making them a common method for studying rainfall-induced landslide mechanisms. Traditional studies on slope stability under rainfall infiltration conditions assume a uniform distribution of rainfall intensity. However, flood discharge fog rainfall differs significantly from ordinary rainfall. On one hand, flood discharge fog rainfall has a higher intensity; on the other hand, its intensity exhibits regional variations. Furthermore, traditional slope stability model tests under rainfall infiltration conditions only consider rainfall conditions and do not account for the impact of groundwater level changes on slope stability.

[0004] Therefore, it is necessary to invent a slope model test device that considers the coupling effect of heavy rain, rainfall intensity zoning and groundwater changes in order to conduct in-depth research on the instability mechanism of fractured rock slopes under the coupling effect of flood discharge atomization and groundwater. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a device and method for simulating atomized rain in a physical model test of flood discharge fog and rain. This device uses two streams of water sprayed from two sets of upper and lower atomizing nozzles to collide in the air as atomization source to simulate atomized rain. It can more realistically simulate the atomization effect produced by the collision and air mixing between water tongues in the air during the energy dissipation process of high dam spillway, provide atomized rain conditions for physical experiments, and simulate the change law of slope under flood discharge fog and rain.

[0006] Technical Solution: The present invention provides a fogging and rain simulation device and method for a physical model test of flood discharge fogging and rain, comprising a fogging and rain simulation module, a model box, a hydraulic lifting device, and a rainwater return device. The fogging and rain simulation module includes a water supply tank, a booster pump I, a booster pump II, a water delivery pipe I, a water delivery pipe II, a flow meter I, a flow meter II, a water distribution pipe I, a water distribution pipe II, an inlet pipe I, an inlet pipe II, a fogging nozzle I, a fogging nozzle II, an angle adjustment device, and a hose. The fogging nozzle I and the fogging nozzle II are set at different heights. The angle adjustment device is set at the upper fogging nozzle. The model box is used to place a slope model. The hydraulic lifting device is set below the model box and is used to adjust the inclination of the slope model inside the model box. The rainwater return device includes a return water pipe and a water pump, and is set between the water supply tank and the model box to recover rainwater inside the model box.

[0007] Preferably, the first atomizing nozzle is connected to the water supply tank through the first water supply pipe, the first hose, the first water distribution pipe, and the first water inlet pipe. The first water supply pipe is equipped with a booster pump and a flow meter. The second atomizing nozzle below is connected to the water supply tank through the second water supply pipe, the second water distribution pipe, and the second water inlet pipe. The second water supply pipe is equipped with a booster pump and a flow meter.

[0008] Preferably, a row of holes is opened on one side wall of the water distribution pipe, which are evenly arranged. One end of the upper water distribution pipe is used to connect to the hose, and the other end is connected to the water inlet pipe through the side wall hole. The other end of the water inlet pipe is connected to the atomizing nozzle. One end of the lower water distribution pipe is connected to the water supply pipe, and the other end is connected to the water inlet pipe, which is connected to the atomizing nozzle, through the side wall hole. The other end of the water inlet pipe is connected to the atomizing nozzle.

[0009] Preferably, the angle adjustment device is only installed in the upper atomizing nozzle 1 to adjust the water outlet angle of the upper atomizing nozzle. The angle can be adjusted from 0 to 90 degrees. The angle adjustment device is equipped with a flexible hose to connect the water supply pipe 1 and the water distribution pipe 1. The angle adjustment device is equipped with a bolt. After adjusting to the designed water outlet angle, tightening the bolt will fix the water outlet angle.

[0010] As a preferred option, the model box has dimensions of 7m×1m×4m, with both sides sealed by transparent plexiglass panels. The bottom of the plexiglass panels has openings for drainage. The rear and bottom sides are sealed by steel plates. A baffle is installed on the front side, and the top side is open. The test slope model is placed inside the model box, and the rainwater sprayed by atomizing nozzles one and two enters the box from above the front baffle.

[0011] Preferably, the hydraulic lifting device is located on the underside of the slope model placed in the model box, which can adjust the angle between the bottom of the model box and the ground.

[0012] Preferably, the rainwater return device is installed between the water supply tank and the model box. One end of the return water pipe is connected to the bottom of the water supply tank, and the other end is connected to the drainage holes set on both sides of the model box. A water pump is installed in the middle of the return water pipe.

[0013] As a preferred option, the rainwater sprayed from the two sets of atomizing nozzles 1 and 2 is sprayed onto the slope model after the collision, and the position of the collision is controlled by the angle adjustment device.

[0014] Preferably, the rainfall intensity is jointly controlled by booster pump one, booster pump two, and atomizing nozzle one and atomizing nozzle two. The nozzles of atomizing nozzle one and atomizing nozzle two are detachable nozzles, which can be easily replaced with nozzles of different orifice diameters. During the test, the rainfall intensity is changed by adjusting the pressure of booster pump one and booster pump two and the orifice diameter of atomizing nozzle one and atomizing nozzle two.

[0015] A test method for a flood discharge fog rain physical model test fog rain simulation device, applicable to the device as described above, including:

[0016] (1) Before the test, debug the hydraulic lifting device, booster pump, water pump, atomizing nozzle and angle adjustment device, turn on the booster pump, adjust the angle adjustment device to ensure that the water sprayed from the upper and lower atomizing nozzles can collide in the box, tighten the bolts of the angle adjustment device to fix the water outlet angle.

[0017] (2) Prefabricate the slope model in the model box, and embed pore water pressure sensor, water content sensor and soil pressure sensor during the construction of the model slope. Complete the slope construction and maintenance until the experimental requirements are met. Adjust the hydraulic lifting device to the required angle and conduct tests on slopes at different angles under atomized rain infiltration.

[0018] (3) Turn on the booster pump, set the pressure and record it. At the same time, record the corresponding flow meter reading. The water source in the water supply tank flows through the water supply pipe, is boosted by the booster pump and enters the water distribution pipe, then flows into the water inlet pipe through the water distribution pipe, and finally sprays out from the atomizing nozzle. The two streams of water sprayed from the upper and lower atomizing nozzles collide in the model box to produce splashing and atomizing effects.

[0019] (4) When water begins to accumulate in the model box, turn on the water pump installed in the rainwater return device to return the water in the model box to the water supply tank.

[0020] (5) Adjust the pressure of the booster pump and record the corresponding flow meter reading. Change the amount of rainfall and the magnitude of rainfall pressure to conduct experiments under different atomized rain intensities and observe the infiltration of fog and rain.

[0021] (6) Conduct subsequent seepage failure experiments and process the data;

[0022] (7) Disassembly of the test apparatus and cleaning of the test site.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This device provides a misting rain simulation apparatus and test method for physical model tests of flood discharge misting rain. Using the above technical solution, physical model tests of slope misting rain infiltration under different misting rain intensities and slope model angles can be conducted. Specifically, it is manifested as follows:

[0025] 1. This device generates two streams of water through the collision and air mixing in the air by two sets of atomizing nozzles, which is more similar to the actual atomization method. The upper atomizing nozzle is equipped with an angle adjustment device, which can be manually adjusted to the position where the water streams from the upper and lower nozzles collide and the position where the atomization source is generated.

[0026] 2. Adjusting the pressure of the booster pump and replacing the atomizing nozzles with different orifice sizes can adjust the intensity of fog and rain (dense fog, light fog, light fog);

[0027] 3. A hydraulic lifting device is installed on the lower side of the model box where the slope model is placed, which can adjust the slope inclination angle and reduce the workload of making high and steep slope models.

[0028] 4. This device is equipped with a rainwater return system, which pumps the water accumulated in the model box after the test back to the water supply tank, avoiding the possible impact of water accumulation on the slope, realizing the recycling of water resources, saving costs, and also facilitating site cleanup after the test. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the experimental apparatus of the present invention;

[0030] Figure 2 This is a schematic diagram of the fog and rain simulation module structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the atomizing nozzle assembly of the present invention;

[0032] Figure 4 This is a schematic diagram of the model box and hydraulic lifting device of the present invention;

[0033] Figure 5 This is a schematic diagram of the rainwater recirculation module of the present invention. Detailed Implementation

[0034] Example 1: As Figure 1 - Figure 5 As shown, a fogging rain simulation device for a physical model test of flood discharge fogging rain includes a fogging rain simulation module, a model box 16, a hydraulic lifting device 17, and a rainwater return device. The fogging rain simulation module is placed on the front side of the model box 16, the hydraulic lifting device 17 is set on the bottom side of the model box 16, and the rainwater return device is connected between the water supply tank 1 and the model box 16.

[0035] As attached Figure 2 ,3 These are schematic diagrams of a fog and rain simulation module and an atomizing nozzle assembly, including a water supply tank 1, water supply pipe 6, water supply pipe 7, booster pump 2, booster pump 3, flow meters 4 and 5, water distribution pipe 10, water distribution pipe 21, water inlet pipe 12, water inlet pipe 213, atomizing nozzle 14, atomizing nozzle 215, an angle adjustment device 8, and a flexible hose 9. The water supply tank 1 has an outlet hole on its side wall. One end of water supply pipe 6 and water supply pipe 7 are connected to the outlet hole on the side wall of the water supply tank 1, and the other end is connected to booster pump 2 and booster pump 3, respectively. One end of the flexible hose 9 is connected to water supply pipe 6, and the other end passes through the angle adjustment device 8 and connects to water distribution pipe 10. The side walls of water distribution pipe 10 and water distribution pipe 21 have uniformly spaced holes. The water inlet pipe 12 and water inlet pipe 211 have... One end is connected to the side wall holes of water distribution pipe 10 and water distribution pipe 21, and the other end is connected to atomizing nozzle 14 and atomizing nozzle 25. The upper atomizing nozzle 14 is equipped with an angle adjustment device 8 to simulate the downward flow of water. The angle adjustment device 8 can realize the angle adjustment of the upper atomizing nozzle 140 to 90 degrees. It is equipped with bolts, which can be tightened to fix the water outlet angle when adjusted to the required angle. The lower atomizing nozzle 215 is set horizontally to simulate the water tongue that collides with the downward flow of water and mixes with air. The flow meters 4 and 5 are set on water supply pipe 16 and water supply pipe 27 to observe the water output. The flow meter readings and the pressure settings of booster pump 12 and booster pump 23 are used to adjust the amount and pressure of the mist and rain to meet the needs of different mist and rain intensities.

[0036] As attached Figure 4 The diagram shows the structure of the model box and the hydraulic lifting device. The model box 16 measures 7m × 1m × 4m, with both sides sealed by transparent plexiglass panels and the bottom and rear sides sealed by steel plates. A baffle 19 is installed on the front side to prevent rainwater from flowing out of the box after the test, and the top side is open. The test slope model is positioned against the steel plate on the rear side of the model box 16. The simulated mist rain enters the box from above the baffle 19 on the front side of the model box 16. Holes 18 are opened at the bottom of the plexiglass panels as drainage holes. The hydraulic lifting device 17 can adjust the angle between the bottom side of the model box 16, i.e., the bottom side of the test slope model, and the ground within a range of 0 to 30 degrees. When the simulated slope is too steep to build, a slope with a smaller angle can be prefabricated, and then the test slope model can be adjusted to the required angle using the hydraulic lifting device 17. This approach can reduce construction difficulty and save costs.

[0037] As attached Figure 5This is a schematic diagram of a rainwater return device, which includes a return water pipe 20 and a water pump 21. One end of the return water pipe 20 is connected to a water supply tank 1, and the other end is connected to a drain hole 18 on the plexiglass plate of the model box 16. The water pump 21 is installed in the middle of the return water pipe 20 to provide power to pump the water accumulated in the model box 16 back to the water supply tank, so as to avoid the water accumulation in the box being too high and affecting the slope model, and at the same time realize the recycling of water resources.

[0038] A test method for a fogging rain simulation device in a flood discharge fogging physical model experiment:

[0039] 1. Before the test, test the booster pump 12, booster pump 23, water pump 21, atomizing nozzle 14, atomizing nozzle 25 and angle adjustment device 8, etc. Turn on booster pump 12 and booster pump 23, and start spraying water from atomizing nozzle 14 and atomizing nozzle 25. Adjust the angle adjustment device 8 set at the upper atomizing nozzle 14 to ensure that the water sprayed from the upper and lower atomizing nozzles 14 and atomizing nozzle 25 can collide at a suitable position in front of the slope model inside the model box 16. Tighten the bolts of the angle adjustment device 8 to fix the water outlet angle.

[0040] 2. Prefabricate the slope model in the model box 16. During the construction of the model slope, embed pore water pressure sensor, moisture content sensor and soil pressure sensor. Complete the slope construction and maintenance until the experimental requirements are met. Adjust the hydraulic lifting device 17 to make the slope model reach the designed slope.

[0041] 3. Turn on booster pump 1 (2) and booster pump 2 (3), set the pressure and record it. At the same time, record the readings of the corresponding flow meters 4 and 5. The water source in the water supply tank 1 flows through water pipe 1 (6) and water pipe 2 (7), and after being pressurized by booster pump 1 (2) and booster pump 2 (3), it enters water distribution pipe 1 (10) and water distribution pipe 2 (11), and then flows into water inlet pipe 1 (12) and water inlet pipe 2 (13). Finally, it is sprayed out by atomizing nozzle 1 (14) and atomizing nozzle 2 (15). The two streams of water sprayed from the upper and lower sets of atomizing nozzles collide in the tank, which will produce splashing and atomization effects.

[0042] 4. When water begins to accumulate in the model box 16, turn on the water pump 21 installed in the rainwater return device to return the water in the box to the water supply tank 1.

[0043] 5. Adjust the pressure of booster pump 12 and booster pump 23, replace the nozzles with different orifice diameters of atomizing nozzle 14 and atomizing nozzle 25, and record the readings of the corresponding flow meters 4 and 5. Conduct experiments under different atomized rain intensities and observe the infiltration of fog and rain.

[0044] 6. The sensor is connected to a computer via a data acquisition device, which can collect data such as soil pressure, pore water pressure and moisture content inside the slope in real time;

[0045] 7. After the test and data collection are completed, disassemble the test equipment and clean the test site.

[0046] The working principle is as follows: Water in the water supply tank 1 enters the booster pump 2 and booster pump 3 through water supply pipe 1 6 and water supply pipe 2 7 for pressurization. The pressurized water in the upper water supply pipe 1 6 flows through the hose 9 into the water distribution pipe 1 10, and then enters the inlet pipe 1 12 through the hole set in the side wall of the water distribution pipe 1 10. Finally, it is sprayed out by the atomizing nozzle 14. The pressurized water in the lower water supply pipe 2 7 enters the water distribution pipe 2 11, flows through the hole in the side wall of the water distribution pipe 2 11 and enters the inlet pipe 2 13 before being sprayed out by the atomizing nozzle 2 15. The upper atomizing nozzle 14 simulates the downward flow of water. It is adjusted to a suitable angle by the angle adjustment device 8 and collides with the water jet sprayed by the lower atomizing nozzle 2 15. After the two water jets collide in the model box 16, they produce splashing water with characteristics similar to flood discharge mist and rain, which splashes onto the slope model. The changes in soil pressure, pore water pressure and water content inside the slope model are monitored by sensors set inside the model.

[0047] This device simulates mist rain by simulating the collision of two streams of water sprayed from two sets of atomizing nozzles in the air. It can more realistically simulate the atomization effect produced by the collision and air mixing between water tongues in the air during the energy dissipation process of high dam spillway, providing mist rain conditions for physical experiments and simulating the change law of slope under flood discharge mist rain.

Claims

1. A device for simulating fog and rain in a physical model test of flood discharge, characterized in that: The system includes a fog and rain simulation module, a model box (16), a hydraulic lifting device (17), and a rainwater return device. The fog and rain simulation module includes a water supply tank (1), a booster pump (2), a booster pump (3), a water supply pipe (6), a water supply pipe (7), a flow meter (4), a flow meter (5), a water distribution pipe (10), a water distribution pipe (11), an inlet pipe (12), an inlet pipe (13), an atomizing nozzle (14), an atomizing nozzle (15), an angle adjustment device (8), and a hose (9). The atomizing nozzles (14) and (15) are set at different heights. The angle adjustment device (8) is set at the upper atomizing nozzle (14). The model box (16) is used to place the slope model. The hydraulic lifting device (17) is set below the model box (16) and is used to adjust the water level inside the model box (16). The slope model inclination, the rainwater return device includes a return water pipe (20) and a water pump (21), which is set between the water supply tank (1) and the model box (16) to recover the rainwater in the model box (16); the first atomizing nozzle (14) is connected to the water supply tank (1) through the first water supply pipe (6), the hose (9), the first water distribution pipe (10) and the first water inlet pipe (12). The first water supply pipe (6) is equipped with a booster pump (2) and a flow meter (4). The second atomizing nozzle (15) below is connected to the water supply tank (1) through the second water supply pipe (7), the second water distribution pipe (11) and the second water inlet pipe (13). The second water supply pipe (7) is equipped with a booster pump (3) and a flow meter (5); the rainwater sprayed by the two sets of atomizing nozzles (14) and atomizing nozzle (15) collides and sprays onto the slope model. The position of the collision is controlled by the angle adjustment device (8).

2. The fogging rain simulation device for flood discharge fogging physical model test according to claim 1, characterized in that, The side wall of the water distribution pipe 1 (10) has a row of holes evenly arranged. One end of the upper water distribution pipe 1 (10) is used to connect the hose (9), and the other end is connected to the water inlet pipe 1 (12) through the side wall hole. The other end of the water inlet pipe 1 (12) is connected to the atomizing nozzle 1 (14). One end of the lower water distribution pipe 2 (11) is connected to the water supply pipe 2 (7), and the other end is connected to the water inlet pipe 2 (13) through the side wall hole. The other end of the water inlet pipe 2 (13) is connected to the atomizing nozzle 2 (15).

3. The fogging rain simulation device for a physical model test of flood discharge fogging rain according to claim 1, characterized in that, Angle adjustment device (8) is only installed at the upper atomizing nozzle (14) to adjust the water outlet angle of the upper atomizing nozzle. The angle can be adjusted from 0 to 90 degrees. A flexible hose (9) is installed inside the angle adjustment device (8) to connect the water supply pipe (6) and the water distribution pipe (10). The angle adjustment device (8) is equipped with a bolt. After adjusting to the designed water outlet angle, tighten the bolt to fix the water outlet angle.

4. The fogging rain simulation device for a physical model test of flood discharge fogging rain according to claim 1, characterized in that, The model box (16) is 7m×1m×4m in size. Both sides are sealed with transparent plexiglass plates. The bottom of the plexiglass plates has holes for drainage (18). The back and bottom sides are sealed with steel plates. A baffle (19) is set on the front side, and the top side is open. The test slope model is placed inside the model box (16). The rainwater sprayed by the first atomizing nozzle (14) and the second atomizing nozzle (15) enters the box from above the baffle (19) on the front side of the model box (16).

5. The fogging rain simulation device for a physical model test of flood discharge fogging rain according to claim 1, characterized in that, The hydraulic lifting device (17) is located on the lower side of the model box (16) where the slope model is placed, and can adjust the angle between the bottom side of the model box (16) and the ground.

6. The fogging rain simulation device for a physical model test of flood discharge fogging rain according to claim 1, characterized in that, The rainwater return device is set between the water supply tank (1) and the model box (16). One end of the return water pipe is connected to the bottom of the water supply tank (1), and the other end is connected to the drainage holes (18) set on both sides of the model box (16). A water pump (21) is set in the middle of the return water pipe (20).

7. The fogging rain simulation device for a physical model test of flood discharge fogging rain according to claim 1, characterized in that, The rainfall intensity is controlled by the joint control of the booster pump 1 (2), booster pump 2 (3) and the nozzles of atomizing nozzle 1 (14) and atomizing nozzle 2 (15). The nozzles of atomizing nozzle 1 (14) and atomizing nozzle 2 (15) are detachable nozzles, which can be easily replaced with nozzles of different orifice diameters. During the test, the rainfall intensity is changed by adjusting the pressure of booster pump 1 (2) and booster pump 2 (3) and the orifice diameter of atomizing nozzle 1 (14) and atomizing nozzle 2 (15).

8. A test method for a flood discharge fog rain physical model test fog rain simulation device, applicable to the device as described in any one of claims 1-7, characterized in that, include: Prefabricate the slope model in the model box (16) and embed sensors. Adjust and fix the hydraulic lifting device (17) and angle adjustment device (8). Turn on the booster pump one (2) and booster pump two (3). After the water in the water supply tank (1) is boosted by the booster pump one (2) and booster pump two (3), it enters the atomizing nozzle one (14) and atomizing nozzle two (15) through the water supply pipe one (6), water supply pipe two (7), water distribution pipe one (10), water distribution pipe two (11), and water inlet pipe one (12) and water inlet pipe two (13). The water is sprayed out by the upper and lower two sets of atomizing nozzle one (14) and atomizing nozzle two (15) and collides. The splash water generated after the collision will splash onto the model slope in the model box (16). The sensors embedded in the model slope monitor the changes in soil pressure, pore water pressure and water content inside the model slope.

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