CN210071814U - Supergravity raininess strong slope rainfall simulation device - Google Patents
Supergravity raininess strong slope rainfall simulation device Download PDFInfo
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- CN210071814U CN210071814U CN201920458157.7U CN201920458157U CN210071814U CN 210071814 U CN210071814 U CN 210071814U CN 201920458157 U CN201920458157 U CN 201920458157U CN 210071814 U CN210071814 U CN 210071814U
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Abstract
The utility model relates to a ground test technique aims at providing a hypergravity heavy rain strong slope rainfall analogue means. The model box is arranged on the supergravity centrifuge, a slope model and a rainfall system are arranged in the model box, and the rainfall system comprises a plurality of groups of nozzles arranged relative to the surface of the slope model; each group of nozzles consists of an air atomizing nozzle, a round atomizing nozzle and a square atomizing nozzle, and the three nozzles are distributed in a triangular mode with symmetrical centers; each nozzle is respectively connected to three water delivery branch pipes according to the type of the nozzle, and each water delivery branch pipe is provided with an electric control valve. The utility model provides a problem that rainfall intensity can't be adjusted on a large scale among the current hypergravity test to compromise the requirement of hypergravity test to aspects such as raindrop particle diameter and rainfall homogeneity.
Description
Technical Field
The utility model relates to a ground test technique, in particular to rainfall device that can simulate multiple rainfall under hypergravity environment.
Background
The supergravity test is one of important test means in the field of geotechnical engineering. The hypergravity test simulates hypergravity through centrifugal force generated by high-speed rotation of a centrifugal machine, and geotechnical engineering disasters with large volume and long time consumption are simulated in a short time by utilizing the 'scale reduction' and 'time reduction' effects of the hypergravity, so that the hypergravity test has good similarity. In the test process, the rainfall and the rainfall uniformity are required to be accurately controlled, and simultaneously, various rain intensities are required to be realized in one test, so that the method is used for researching the process of slope deformation instability caused by various rain intensity combinations such as small rain infiltration, medium rain infiltration and heavy rain washing.
The supergravity rainfall device who uses at present adopts a rainfall nozzle usually, can only simulate the rain condition of certain rainfall scope, can't satisfy the experimental demand of complicated rainfall condition. In addition, raindrop falling in a supergravity environment is influenced by the action of Coriolis force, so that the rainfall uniformity is influenced, and the problem to be solved in the supergravity test is also solved urgently.
SUMMERY OF THE UTILITY MODEL
The utility model discloses the technical problem who solves is, overcomes not enough among the prior art, provides a hypergravity heavy rain strong slope rainfall analogue means.
For solving the technical problem, the utility model discloses a solution as follows:
the rainfall simulation device comprises a model box arranged on a hypergravity centrifuge, wherein a slope model and a rainfall system are arranged in the model box, and the rainfall system comprises a plurality of groups of nozzles arranged relative to the surface of the slope model; each group of nozzles consists of an air atomizing nozzle, a round atomizing nozzle and a square atomizing nozzle, and the three nozzles are distributed in a triangular mode with symmetrical centers; each nozzle is respectively connected to three water delivery branch pipes according to the type of the nozzle, and each water delivery branch pipe is provided with an electric control valve.
In the utility model, the plurality of groups of nozzles are uniformly arranged in the model box, and the spraying ranges of the adjacent groups of nozzles are provided with overlapping cross areas; on the same spraying height, the overlapping area accounts for 15-25% of the coverage area of each group of nozzles.
The utility model discloses in, each group's nozzle keeps unanimous with the distance between the side slope model surface.
In the utility model, the spray nozzle is arranged at the tail end of the spray pipeline and is connected to the water delivery branch pipe through the spray nozzle; the spray pipe is perpendicular to the bottom edge of the side slope model and is provided with a telescopic mechanism, so that the distance between the spray nozzles and the surface of the side slope model can be adjusted.
The utility model discloses in, rainfall system sets up three solenoid valve, relief pressure valve and rotary joint including the water delivery house steward of connecting each water delivery branch pipe on the water delivery house steward, and the rainfall system in the model case meets with outside delivery pipe through the rotary joint on the water delivery house steward.
The utility model discloses in, set up the leading water pipe around the relief pressure valve, leading water pipe end connection water pressure sensor.
The utility model discloses in, an exit end of three way solenoid valve is connected to the pressure release pipeline.
The utility model discloses in, each group's nozzle constitutes with square layout mode in the simulation case.
The principle of the utility model describes:
(I) simulation of multiple rainfall intensities
As shown in figure 1, in the rotation process of the centrifugal machine, a follow-up coordinate system is established, wherein the tangential direction is taken as the x direction, the arm direction is taken as the y direction, the heaven-earth direction is taken as the z direction, the included angle between the speed v direction and the xy plane when raindrops are sprayed out of a spray head is set as α, and the included angle between the projection of the speed v on the xy plane and the x axis is set as β.
In a hypergravity centrifugal simulation environment, in order to meet the requirement of similarity law, under the hypergravity of Ng, the particle size of the raindrop model is reduced to 1/N of that of a prototype, and the relation of the raindrop particle size range simulated by nozzles of different models in the figure 2 under the condition of a plurality of N values is obtained according to the calculation result of the relation between the particle size of the prototype raindrop and the particle size of the model raindrop and the experimental result of the particle size range simulated by the nozzle models of different models.
Take an air atomizing nozzle, a round atomizing nozzle and a square atomizing nozzle as examples: as can be seen from fig. 2, each individual nozzle cannot fully satisfy the equivalent of raindrop particle size and rainfall intensity: the air atomizing nozzle can simulate the model raindrop with the grain diameter range of 0-20 mu m, the round atomizing nozzle can simulate the model raindrop with the grain diameter range of 20-60 mu m, and the square atomizing nozzle can simulate the model raindrop with the grain diameter range of 60-100 mu m. The proper nozzle is selected according to the conditions of the specific test simulation (light rain, medium rain and heavy rain) and the test centrifugal acceleration. In order to simulate the rain conditions of light rain, medium rain, heavy rain and heavy rain if the centrifugal acceleration is 100g in this experiment, it can be seen from fig. 2 that the air atomizing nozzle, the circular atomizing nozzle and the circular atomizing nozzle should be selected respectively. Therefore, when the nozzle group is arranged, if the air atomizing nozzles, the circular atomizing nozzles and the square atomizing nozzles are arranged in a triangular mode, all rainfall states under the common supergravity centrifugal acceleration can be completely covered, and the effect of simulating various rainfall intensities is achieved.
Influence of the Coriolis force
The mass points which do linear motion in the rotating system have the tendency of continuing to move along the original motion direction due to inertia; however, since the system itself is rotating, after a period of motion, the position of the mass point in the system changes, and the original direction of motion will deviate to some extent if viewed from the perspective of the rotating system. According to the theory of newton mechanics, the tendency of the straight line motion of the mass point to deviate from the original direction is attributed to the action of an external force, which is coriolis force. From a physical point of view, coriolis force, like centrifugal force, is not a force that is actually present in the inertial system, but is reflected in a non-inertial system by inertial action.
The calculation formula of the Coriolis force is as follows:
F＝-2mω×v′
wherein, F is Coriolis force; m is mass of mass point; v' is the velocity (vector) of motion relative to the rotating reference system particles; ω is the angular velocity (vector) of the rotating system; in a centrifugal simulation environment, the Coriolis force has a great influence on the process of raindrops falling in the rainfall simulation process. According to the theory, the nozzle head will generate an ellipse-like coverage (different circles from large to small represent 100g, 50g, 20g and the spraying range under normal gravity) as shown in fig. 3 under the action of the supergravity centrifugal machine. As can be seen from the figure, as the coriolis force increases, the rainfall area "elongates" along the x direction, and the elongation degree increases as N increases, so under the actual test conditions, the influence of the coriolis force should be avoided as much as possible.
(III) uniformity of rainfall
In order to ensure the uniformity of rainfall, a certain overlap area is arranged between the two nozzles, and the range of the overlap area is generally about 20% according to experimental data.
For example, if the mold box has a length of 2m and a width of 1.1m, the overlap length in the width direction is set to 0.11m, and 3 sets of nozzles are arranged in the width direction, the distance h between the nozzles and the mold floor is 0.31.42m when the distance h is calculated from the droplet trajectory analysis under the condition of 100 g. When the total length b of the mold box is 2m and a certain spray overlapping area is provided, and 6 nozzles are provided in the longitudinal direction of the mold box, the length of the spray overlapping area between two adjacent nozzles is 0.105m (0.228 × 15 is 3.42m, (3.42-2.8)/14 is 0.044m), and the ratio of the spray overlapping area is 23.8% (0.105/0.44 is 23.8%). According to the design, the uniformity of rainfall can be effectively ensured.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the utility model provides a problem that rainfall intensity can't be adjusted on a large scale among the current hypergravity test to compromise the requirement of hypergravity test to aspects such as raindrop particle diameter and rainfall homogeneity. The device achieves the purposes of simulating a plurality of rainfall intensities such as light rain, medium rain, heavy rain and the like and improving the rainfall uniformity in the same test through the reset nozzle type, the arrangement of the nozzle positions and the setting of the overlapping area of the nozzle coverage; according to the influence degree of the Coriolis force on raindrops under different hypergravity, the distance between the nozzle and the slope surface is adjusted so as to reduce the influence of the Coriolis force and improve the rainfall uniformity.
2. The utility model discloses a carry and carry the airborne device of hypergravity centrifuge and work under the hypergravity environment, can simulate the rainfall of multiple rain intensity under the hypergravity environment, disclose rainfall and slope soil body under the hypergravity and flow the mechanism of causing a disaster of solid-liquid coupling effect.
3. The utility model discloses stand in the hypergravity environment, through changing nozzle arrangement, according to side slope appearance adjustment nozzle length, set up certain overlapping cross section for the nozzle to make it reach the purpose of simulating multiple rainfall intensity under the hypergravity environment, and guarantee the rainfall homogeneity in the at utmost.
Drawings
FIG. 1 is a schematic diagram of a rainfall spray system arrangement;
FIG. 2 shows the sizes of raindrops of different types of nozzles corresponding to prototype sizes at different g values;
FIG. 3 is a top view of the spray range of a single nozzle in the xz plane at different values of g;
FIG. 4 is a front view of the experimental apparatus in the example.
FIG. 5 is a top view of the experimental apparatus in the example.
FIG. 6 is a front view and a top view of the nozzle block arrangement.
Fig. 7 is a schematic view of a rainfall system.
Fig. 8 is a schematic view of a widthwise nozzle arrangement.
The reference numbers in the figures are: 1, a model box; 2, a side slope model; 3 an air atomizing nozzle; 4, a circular atomizing nozzle; 5, a square atomizing nozzle; 6, a rainfall system; 7 a rotary joint; 8 a pressure reducing valve; 9, a three-way electromagnetic valve; 10 water pressure sensor; 11 a nozzle; and the spraying pipelines are 3-1, 4-1 and 5-1.
Detailed Description
The utility model provides a high rainfall strong side slope rainfall analogue means of hypergravity, including installing mold box 1 on hypergravity centrifuge, be equipped with side slope model 2 and rainfall system 6 in mold box 1, the latter includes a plurality of groups nozzle 11 of arranging for side slope model 2 surface. As shown in fig. 6, each set of nozzles 11 is composed of an air atomizing nozzle 3, a circular atomizing nozzle 4 and a square atomizing nozzle 5, and the three nozzles are arranged in such a manner that their centers of symmetry constitute a triangle. Each nozzle group is formed by arranging 3 nozzles capable of simulating different rainfall intensities according to a triangular layout mode, the effect of simulating different rainfall intensities under different hypergravity can be realized, and the rainfall process under the real condition is restored. The nozzles of each group can be arranged in a variety of ways in the simulation chamber, for example, in a square arrangement (3 in the width direction of the chamber and 6 in the length direction of the chamber) as shown in fig. 5. Each nozzle 11 is connected to three water delivery branch pipes according to the type of the nozzle, and each water delivery branch pipe is provided with an electric control valve.
In order to avoid the influence of Coriolis force on raindrops in a supergravity environment, the falling heights of the raindrops are the same, the raindrop coverage range of each nozzle is consistent, and the rainfall uniformity and the experimental accuracy are improved. The distance between each group of nozzles 11 and the surface of the side slope model 2 is kept consistent (as shown in fig. 4). For example, the spray nozzles 11 are installed at the ends of the shower pipes 3-1, 4-1, 5-1 of the rainfall system 6 (as schematically shown in the left side of FIG. 6), through which they are connected to the respective water delivery branch pipes. The spray pipe is perpendicular to the bottom edge of the side slope model 2 and is provided with a telescopic mechanism, so that the distance between the spray nozzles 11 and the surface of the side slope model 2 can be adjusted.
The nozzles 11 in each group are uniformly arranged in the model box 2, and the spraying ranges of the nozzles 11 in each adjacent group have an overlapping intersection region; on the same spraying height, the overlapping area accounts for 15-25% of the coverage area of each group of nozzles 11. Tests show that when the overlapping and crossing area accounts for about 20% of the coverage area of the nozzle, the uniformity of rainfall simulation can reach more than 90%.
As shown in fig. 7, the rainfall system 6 comprises a water delivery main connected with each water delivery branch pipe (the spray pipes for installing the nozzles 11 are respectively connected to the water delivery main through the respective water delivery branch pipes), a three-way electromagnetic valve 9, a pressure reducing valve 8 and a rotary joint 7 are arranged on the water delivery main, and the rainfall system 6 in the model box 2 is connected with an external water supply pipe through the rotary joint 7 on the water delivery main. The front and the back of the pressure reducing valve 8 are respectively provided with a water conduit, and the end part of the water conduit is connected with a water pressure sensor 10. One outlet end of the three-way electromagnetic valve 9 is connected to the pressure relief pipeline.
Example of a method of use of the apparatus:
first, the components are mounted in the aforementioned connection manner. Before the hypergravity centrifugal machine is started, the three-way electromagnetic valve 9 is not electrified and is in a closed state. The water delivery main pipe of the rainfall system 6 is connected with an external water supply pipeline through a rotary joint 7, and the external water supply pipeline can be provided with a filter for filtering water impurities so as to avoid blocking a nozzle. The water pressure sensor 10 displays water pressure fluctuation in the pipeline, and after the starting acceleration value of the centrifugal machine is stable, the water pressure sensor 10 can monitor the change of the water pressure of the pipeline along with the increase of the centrifugal g value in real time. According to the test result of the uniformity of the rainfall device under the hypergravity, the water pressure of the pipeline can be increased sharply along with the increase of the g value under the action of the centrifugal force, the water pressure can be stabilized at a test target value through the pressure reducing valve 8, and the water pressure sensor 10 monitors the water pressure value after pressure reduction in real time. The normally closed two-position three-way electromagnetic valve 9 is used for controlling the opening and closing of the nozzle, and the three-way electromagnetic valve 9 is opened when the nozzle is electrified to form rainfall; when the power is off, the three-way electromagnetic valve 9 is closed, and water remained in the pipeline between the three-way electromagnetic valve 9 and the nozzle 11 is discharged through a pressure relief pipeline connected with the three-way electromagnetic valve 9, so that the phenomenon that the water drips through the nozzle 11 and impacts the surface of a model soil body is avoided.
The device in this example adopts each group of nozzles to closely arrange in a triangular shape with an air atomizing nozzle 3, a circular atomizing nozzle 4 and a square atomizing nozzle 5, and when different rain conditions are simulated, according to the experimental result shown in fig. 4, the electric control valve on the corresponding water delivery branch pipe is opened, and the water pressure is adjusted to achieve the corresponding conditions. For example, under the environment of 50g, when small rain is simulated, the air atomizing nozzle 3 is opened, and the water pressure is adjusted to enable the diameter of model raindrops to reach 10-20 microns; when the rain is simulated, the circular atomizing nozzle 4 is opened, and the water pressure is adjusted to enable the diameter of model raindrops to reach 30-45 microns; when rainstorm is simulated, the circular atomizing nozzle 4 is opened, and the water pressure is adjusted to enable the diameter of model raindrops to reach 45-60 microns; when heavy rainstorm is simulated, the square atomizing nozzle 5 is opened, and the water pressure is adjusted to enable the diameter of model raindrops to reach more than 60 microns. Therefore, the effect of effectively simulating different rain conditions can be achieved in the same set of equipment.
Meanwhile, in order to reduce the action of Coriolis force, the uniformity of rainfall is ensured on the surface of the whole slope model 2, and the length of the spray pipes of each group of nozzles 11 is adjusted according to actual conditions, so that the falling distances of raindrops are the same. The nozzle groups along the length of the mold box are individually labeled A, B, C, D, E, F.
According to the calculation:
h＝r×cot35°＝0.314m
in the formula, r is the radius of a rainfall spraying range; the falling distance h is preferably 0.314 m. According to conditions such as model box parameters and slope model parameters, the distance from the nozzle group A, B, C, D, E, F to the slope model is h by adjusting the length of the water supply pipe behind the nozzle, so that the deviation of the spraying range caused by different descending distances under the influence of Coriolis force is eliminated, and the effect of uniform spraying coverage is achieved.
Claims (8)
1. A rainfall simulation device for a supergravity and heavy rain side slope comprises a model box arranged on a supergravity centrifugal machine, wherein a side slope model and a rainfall system are arranged in the model box, and the model box comprises a plurality of groups of nozzles arranged relative to the surface of the side slope model; the spray nozzle is characterized in that each group of spray nozzles consists of an air atomizing nozzle, a round atomizing nozzle and a square atomizing nozzle, and the three spray nozzles are distributed in a triangular mode with symmetrical centers; each nozzle is respectively connected to three water delivery branch pipes according to the type of the nozzle, and each water delivery branch pipe is provided with an electric control valve.
2. The apparatus of claim 1, wherein the plurality of groups of nozzles are uniformly arranged in the mold box, and the spray ranges of adjacent groups of nozzles have overlapping intersection regions; on the same spraying height, the overlapping area accounts for 15-25% of the coverage area of each group of nozzles.
3. The apparatus of claim 1 wherein the distance between each set of nozzles and the surface of the slop model is maintained uniform.
4. The apparatus of claim 3, wherein the spray nozzles are mounted at the end of the spray pipe and connected to the water delivery manifold therethrough; the spray pipe is perpendicular to the bottom edge of the side slope model and is provided with a telescopic mechanism, so that the distance between the spray nozzles and the surface of the side slope model can be adjusted.
5. The device as claimed in any one of claims 1 to 4, wherein the rainfall system comprises a water delivery main connected with each water delivery branch pipe, a three-way electromagnetic valve, a pressure reducing valve and a rotary joint are arranged on the water delivery main, and the rainfall system in the model box is connected with an external water supply pipe through the rotary joint on the water delivery main.
6. The device as claimed in claim 5, wherein the pressure reducing valve is provided with a water conduit at the front and the rear, and the end of the water conduit is connected with a water pressure sensor.
7. The apparatus of claim 5, wherein an outlet end of the three-way solenoid valve is connected to a pressure relief line.
8. The apparatus of claim 5, wherein the sets of nozzles are configured in a square arrangement in the simulated box.
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| CN201920458157.7U CN210071814U (en) | 2019-04-07 | 2019-04-07 | Supergravity raininess strong slope rainfall simulation device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110057998A (en) * | 2019-04-07 | 2019-07-26 | 浙江大学 | A kind of rainy strong side slope rainfall simulator of hypergravity |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110057998A (en) * | 2019-04-07 | 2019-07-26 | 浙江大学 | A kind of rainy strong side slope rainfall simulator of hypergravity |
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