A sand adding device for aerated stirring suspended sediment experiment

Abstract

The invention discloses an aerated stirring suspended sediment experiment sand adding device, comprising a suspended sediment stirring cylinder, a stirring shaft, stirring blades, an air pump, an air inlet conduit, a first aeration valve, a suspended sediment outflow valve, a variable frequency water pump, a flow meter, an outflow pipe, a suspended sediment outflow port, and a second aeration valve. The stirring blades are fixed on the stirring shaft to form a stirrer, which is installed at the central axis position of the suspended sediment stirring cylinder. The bottom of the suspended sediment stirring cylinder is connected to the top center position of the suspended sediment outflow port through an outflow pipe. The suspended sediment outflow valve, the variable frequency water pump, and the flow meter are sequentially installed on the outflow pipe. The air pump is connected to the air inlet conduit, which is divided into two paths, one of which is connected to the hemispherical aeration port at the bottom center of the suspended sediment stirring cylinder through the first aeration valve, and the other is connected to the side bottom of the suspended sediment outflow port through the second aeration valve. The invention makes the water and sand in the sand adding container evenly mixed without residue, the sand adding port is not silted, and the suspended sediment concentration is more accurate and stable during the experiment.

Description

Technical Field

[0001] The invention relates to a suspended sediment experimental device for river sediment dynamics, in particular to a device for simulating the suspended sediment concentration of water flow during sediment flume experiments or river engineering model experiments. Background Art

[0002] Natural rivers carry sediment. When the sediment content in the river is high, it can shape a "hanging river on the ground" and create new territory; when the sediment content is low, it causes the river channel to cut down, affecting the safety of the embankment, and the estuary area changes from a siltation type to an erosion type. In recent years, due to the construction of reservoirs on major rivers, a large amount of river sediment has been intercepted, causing a sharp decrease in the sediment content in the river, resulting in the "clear" Yellow River and the "clear" Yangtze River, causing the riverbed to coarsen and changing the aquatic biological environment. Therefore, it is urgent to study the migration law of river sediment in the water flow, especially the migration law of suspended sediment. At present, the study of the movement law of suspended sediment is generally carried out in flume equipment or river engineering physical models. Therefore, it is crucial to develop a suspended sediment adding device suitable for flume or river engineering physical models.

[0003] The existing suspended sediment adding devices in domestic universities and research institutes either add dry sand directly into the water tank or add sand by mixing water and sand. These sand adding devices often have problems such as local siltation, silt blockage at the suspended sediment outflow outlet, and unstable suspended sediment concentration, resulting in a large error between the set suspended sediment concentration and the actual concentration, and the sand adding effect is difficult to meet the experimental needs. Summary of the invention

[0004] In order to solve the problem of poor sand adding effect of sand adding equipment when conducting suspended sediment experiments, the present invention provides an aerated stirring suspended sediment experiment sand adding device, so that the water and sand in the sand adding container are evenly mixed without residue, the sand adding port is not silted up, and the suspended sediment concentration during the experiment is more accurate and stable.

[0005] The purpose of the present invention is achieved through the following technical solutions: an aerated stirring suspended sediment experiment sand adding device, comprising a suspended sand stirring cylinder, a stirring shaft, stirring blades, an air pump, an air inlet duct, a first aeration valve, a suspended sand outflow valve, a variable frequency water pump, a flow meter, an outflow pipe, a suspended sand outflow port, and a second aeration valve. The stirring blades are fixed on the stirring shaft to form an agitator, and the agitator is installed at the center axis position of the suspended sand stirring cylinder. The bottom of the suspended sand stirring cylinder is connected to the top center position of the suspended sand outflow port through the outflow pipe, and the suspended sand outflow valve, the variable frequency water pump and the flow meter are installed on the outflow pipe in sequence. The air pump is connected to the air inlet duct, and the air inlet duct is divided into two paths, one of which is connected to the hemispherical aeration port at the bottom center of the suspended sand stirring cylinder through the first aeration valve; the other is connected to the side bottom of the suspended sand outflow port through the second aeration valve.

[0006] Furthermore, the hemispherical aeration port is located at the bottom center of the suspended sand mixing cylinder and is a hemispherical hollow structure with aeration holes evenly distributed on the spherical wall.

[0007] Furthermore, the suspended sand outlet is a rectangular parallelepiped structure that is square outside and hollow inside, and a plurality of rectifying tubes penetrate the interior of the suspended sand outlet.

[0008] Furthermore, the rectifier tube is a hollow tube, and a plurality of circular holes are evenly distributed on the tube wall.

[0009] The beneficial effects of this device are:

[0010] 1. The aeration mixing method is adopted, and a hemispherical aeration port is added at the bottom of the suspended sand mixing cylinder. The sediment particles rotate with the mixing blades and the water flow, but at the same time they tend to sink due to gravity. The aeration unit composed of the air pump and the hemispherical aeration port aerates the bottom of the cylinder, and the gas goes up to resist the sinking of the sediment particles, ensuring that the sediment concentration of the upper and lower layers in the suspended sand mixing barrel is consistent, and avoiding the accumulation of some sediment at the bottom of the cylinder.

[0011] 2. The porous rectifier pipe arranged in the suspended sand outlet can rectify the water flow in the flume or physical model on the one hand. On the other hand, since the aeration pipe is connected to the bottom of the side of the suspended sand outlet, the aeration effect from bottom to top makes it difficult for the suspended sand inside the suspended sand outlet to settle. The suspended sand water flows evenly from the circular holes on the rectifier pipe into the test flume or physical model without blockage. The uniformity of the suspended sediment concentration of the outflow from the suspended sand outlet is guaranteed on the cross section, and there will be no situation where the concentration is thin at the top and thick at the bottom, or the concentration is high in some places and small in the surrounding areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the present invention;

[0013] Figure 2 It is a schematic diagram of the structure of the stirring shaft;

[0014] Figure 3 It is a schematic diagram of the structure of the stirring blade;

[0015] Figure 4 This is the front view of the hemispherical aeration port;

[0016] Figure 5 It is a top view of the hemispherical aeration port;

[0017] Figure 6 This is the front view of the suspended sand outflow outlet;

[0018] Figure 7 It is a side view of the suspended sand outflow outlet;

[0019] Figure 8 This is a top view of the suspended sand outflow outlet;

[0020] Fig. 9 is a schematic diagram of the structure of the outlet pipe;

[0021] In the figure: a suspended sand mixing cylinder 1, a mixing shaft 2, a mixing blade 3, an air pump 4, an air inlet duct 5, a first aeration valve 6, a hemispherical aeration port 7, an aeration outlet 8, a suspended sand outflow valve 9, a variable frequency water pump 10, a flow meter 11, an outflow pipe 12, a suspended sand outflow port 13, a rectifier pipe 14, and a second aeration valve 15. DETAILED DESCRIPTION

[0022] like Figure 1 As shown, an aerated stirring suspended sediment experiment sand adding device comprises a suspended sand stirring cylinder 1, a stirring shaft 2, a stirring blade 3, an air pump 4, an air inlet conduit 5, a first aeration valve 6, a suspended sand outflow valve 9, a variable frequency water pump 10, a flow meter 11, an outflow pipe 12, a suspended sand outflow port 13, a rectifier 14, and a second aeration valve 15. The stirring blade 3 is fixed on the stirring shaft 2 to form a stirrer, and the stirrer is installed at the center axis position of the suspended sand stirring cylinder 1. The bottom of the suspended sand stirring cylinder 1 is connected to the top center position of the suspended sand outflow port 13 through the outflow pipe 12, and the suspended sand outflow valve 9, the variable frequency water pump 10 and the flow meter 11 are installed on the outflow pipe 12 in sequence. The air pump 4 is connected to the air inlet conduit 5, and the air inlet conduit 5 is divided into two paths, one of which is connected to the hemispherical aeration port 7 at the bottom center of the suspended sand stirring cylinder 1 through the first aeration valve 6; the other is connected to the side bottom of the suspended sand outflow port 13 through the second aeration valve 15.

[0023] like Figure 1-3 As shown, a stirring blade 3 is fixed on the stirring shaft 2. The stirring blade 3 is an elliptical structure, with a total of 4 pieces, and is symmetrical in structure from top to bottom and from left to right. The lowest point of the stirring blade 3 located at the lower part of the stirring shaft 2 is close to the bottom of the suspended sand stirring cylinder 1.

[0024] like Figure 1 , 4 As shown in FIG. 5 , the hemispherical aeration port 7 is located at the bottom center of the suspended sand mixing cylinder 1 and is a hemispherical hollow structure, and aeration holes 8 are evenly distributed on the spherical wall.

[0025] like Figure 1 , 6 As shown in FIG. 9 , the suspended sand outlet 13 is a rectangular parallelepiped structure with a square outside and a hollow inside. The outlet pipe 12 is connected to the top of the suspended sand outlet 13, and the air intake duct 5 is connected to the bottom of the side of the suspended sand outlet 13. Numerous rectifying pipes 14 penetrate the interior of the suspended sand outlet 13.

[0026] like Fig. 9 As shown, the rectifying tube 14 is a hollow tube with numerous circular holes evenly distributed on the tube wall to facilitate the outflow of suspended sand water.

[0027] The working process of the present invention is as follows: After a certain amount of water and sediment are added to the suspended sand mixing cylinder 1, they are mixed together under the rotation of the mixing blade 3. The air pump 4 and the first aeration valve 6 are opened, and the generated gas enters the suspended sand mixing cylinder 1 through the air inlet duct 5, the first aeration valve 6 and the hemispherical aeration port 7. During the process of gas floating, part of the sediment that is easy to settle is driven to rise, and the water and sand in the suspended sand mixing cylinder 1 reach the same suspended sand concentration in the upper and lower layers under the combined action of aeration and stirring.

[0028] Open the suspended sand outflow valve 9, the variable frequency water pump 10 and the second aeration valve 15, and the uniformly stirred suspended sand water flow is sucked into the outflow pipe 12 by the variable frequency water pump 10, and enters the interior of the suspended sand outlet 13 from the top of the suspended sand outlet 13, and the flow meter 11 detects the flow of the suspended sand water flow in real time. At the same time, the gas generated by the air pump 4 enters the interior of the suspended sand outlet 13 from the side bottom of the suspended sand outlet 13 through the second aeration valve 15. The suspended sand water flow is aerated from bottom to top by the gas, and is evenly mixed inside the suspended sand outlet 13.

[0029] Several hollow rectifier tubes 14 are arranged inside the suspended sand outlet 13. The rectifier tubes 14 are covered with round holes for the suspended sand water to flow out. On the one hand, the rectifier tubes 14 can rectify the water flow in the water tank or physical model. On the other hand, the suspended sand water flow in the suspended sand outlet flows into the test water tank or physical model and other destinations evenly from the round holes on the rectifier tubes under the effect of aeration. The suspended sand outlet can be prevented from silting up and blocking, and the suspended sediment concentration of the outflow is more accurate and stable.

[0030] Under certain hydraulic and sediment conditions, the calculation formula for the suspended sediment concentration in the water section of the sediment flume is as follows:

[0031] c=m / V; Δm=c·q·Δt; ΔV=(q+Q)·Δt;

[0032]

[0033] The mass of sediment added to the suspended sand mixing cylinder 1 is m, the volume of water added is V, and the sediment content in the suspended sand mixing cylinder 1 after aeration and mixing is c. The flow meter reading of the suspended sand flowing into the water tank through the suspended sand outlet 13 is q, and the flow rate of the sediment water tank is Q. The mass of sediment flowing into the water tank within Δt time is Δm, the volume of water within Δt time is ΔV, and the suspended sediment content of the water tank is C.

[0034] The present invention adopts the method of aeration stirring and aeration sand addition to effectively mix the silt and water into a suspended sand water flow with a consistent concentration and evenly add it to the water tank or physical model, which can effectively prevent the sediment from settling at the bottom and clogging at the outlet during stirring. The water and sand mixing efficiency of the device is high, and the suspended sediment concentration is uniform and stable. Compared with the existing sand addition technology, the uniformity and accuracy of the suspended sand outflow are significantly improved, and it has a wide range of application prospects.

Claims

1. An aerated stirring suspended sediment experiment sand adding device, characterized in that: The invention comprises a suspended sand stirring cylinder (1), a stirring shaft (2), stirring blades (3), an air pump (4), an air inlet conduit (5), a first air injection valve (6), a suspended sand outflow valve (9), a variable frequency water pump (10), a flow meter (11), an outflow pipe (12), a suspended sand outflow port (13), a rectifier pipe (14), and a second air injection valve (15); the stirring blades (3) are fixed on the stirring shaft (2) to form a stirrer, and the stirrer is installed at the central axis position of the suspended sand stirring cylinder (1); the suspended sand stirring cylinder ( The bottom of the suspended sand mixing cylinder (1) is connected to the top center position of the suspended sand outlet (13) through an outlet pipe (12), and a suspended sand outlet valve (9), a variable frequency water pump (10) and a flow meter (11) are installed in sequence on the outlet pipe (12); the air pump (4) is connected to an air intake conduit (5), and the air intake conduit (5) is divided into two paths, one of which is connected to a hemispherical air injection port (7) at the bottom center of the suspended sand mixing cylinder (1) through a first air injection valve (6), and the other of which is connected to the side bottom of the suspended sand outlet (13) through a second air injection valve (15).

2. The aerated stirring suspended sediment experiment sand adding device according to claim 1, characterized in that: The hemispherical aeration port (7) is located at the bottom center of the suspended sand mixing cylinder (1) and is a hemispherical hollow structure with aeration holes (8) evenly distributed on the spherical wall.

3. The aerated stirring suspended sediment experiment sand adding device according to claim 1 is characterized in that: The suspended sand outlet (13) is a rectangular parallelepiped structure that is square outside and hollow inside, and a plurality of rectifying tubes (14) penetrate the interior of the suspended sand outlet (13).

4. The aerated stirring suspended sediment experiment sand adding device according to claim 3 is characterized in that: The rectifier tube (14) is a hollow tube with circular holes evenly distributed on the tube wall.

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