A hydrothermal plume experimental device and method based on variable background flow field

Abstract

The present invention relates to a hydrothermal plume experimental device and method based on a variable background flow field. The experimental device mainly includes the following four parts: an environmental water body background flow field simulation device, a "double-cylinder method" stratified water body generation device, a hydrothermal plume generation and outflow device, and a PIV particle image velocimetry system. The main slide rail is horizontally mounted above the experimental water tank, and the electric trolley is connected to the hydrothermal main pipeline through a pipe clamp. The moving speed can be freely adjusted on the main slide rail to drive the movement of the hydrothermal nozzle. The system can simulate the actual deep-sea background flow field and density stratification phenomenon, carry out hydrothermal plume experiments under different background flow field conditions and stratified environments, and meet the simultaneous measurement of plume morphology, flow field, vorticity and other parameters. It has a simple structure, low cost, simple steps, and good reliability, accuracy and ease of use.

Description

Technical Field

[0001] The invention belongs to the field of buoyancy plume research, and in particular relates to a hydrothermal plume experimental device and method based on a variable background flow field. Background Art

[0002] Plume refers to the plume-like flow pattern of fluid in the environmental medium that is completely or partially driven by buoyancy. The dynamic characteristics of the plume evolution process depend not only on the initial momentum and density as its driving force, but also on the mixing and diffusion rate between the plume material and the environmental fluid and the density difference with the surrounding water body (i.e., the buoyancy). Buoyancy plumes of different spatial and temporal scales are common in nature and industrial applications, such as submarine hydrothermal fluids, volcanic eruptions, meltwater at the bottom of glaciers, and treated urban wastewater discharged into offshore waters.

[0003] Hydrothermal plumes are an important manifestation of buoyancy in nature and are generally considered to be an important representation of active hydrothermal areas in the investigation of deep-sea hydrothermal systems. Polymetallic sulfide deposits with considerable seafloor sedimentary resources migrate with ocean currents in the form of hydrothermal plumes, playing an important role in the material and energy cycle of the deep sea, and have an important impact on the evolution of seawater chemical composition and global climate. Hydrothermal plumes not only promote the accumulation of a large number of potentially valuable minerals, but also support diverse and prosperous ecosystems that display unique life forms. Due to the important significance of buoyancy plumes in regional material circulation and energy exchange processes, their dynamic characteristics have long been widely concerned and studied.

[0004] Flume experiments are a classic method for studying buoyancy plumes. The most commonly used flow field measurement method is particle image velocimetry (PIV), and the most commonly used plume outflow mode is outflow from the bottom of the flume, but it cannot simulate the actual dynamic process of the seabed environment well.

[0005] Among the currently published technical solutions, there is no experimental method for hydrothermal plumes in stratified water bodies that can simulate various variable background flow fields in natural environments in small-scale closed water tanks. Summary of the invention

[0006] The present invention overcomes the defects of the prior art, is not only close to the actual situation, but also reduces the experimental cost and complexity, and provides a hydrothermal plume experimental device and method based on a variable background flow field.

[0007] One aspect of the present invention provides a hydrothermal plume experimental device based on a variable background flow field, comprising:

[0008] Environmental background flow field simulation system composed of main slide rail, pipe clamp, electric trolley and drag reduction device;

[0009] A PIV observation system consisting of a thermometer, a laser source, and a high-speed camera;

[0010] A stratified water body generating device composed of a first water tank, a second water tank, a water tank agitator, a water pipe, a first water outlet valve, a second water outlet valve and an outflow device;

[0011] A hydrothermal plume generating device composed of a heating water tank, a hydrothermal main pipeline, a bypass valve, a bypass pipe and a third water outlet valve;

[0012] The main slide rail is mounted horizontally above the experimental water tank, and the electric trolley is placed on the main slide rail and connected to the hot liquid main pipeline through a pipe clamp. The moving speed can be adjusted on the main slide rail to drive the hot liquid nozzle located in the water tank to move. A drag reduction device connected to the hot liquid nozzle is provided in the movement direction; the hot liquid nozzle is connected to the hot liquid plume generating device.

[0013] Furthermore, the hydrothermal nozzle can freely adjust the depth of penetration into the water surface, and the cross-section of the hydrothermal nozzle nozzle is circular or elliptical.

[0014] Furthermore, the density of the solution in the hydrothermal generation device is greater than the density of the water around the hydrothermal nozzle, and less than the density of the water at the bottom of the experimental tank.

[0015] Furthermore, the drag reducing device is tapered or streamlined.

[0016] Furthermore, the electric trolley is connected to the hot liquid main pipeline through a pipe clamp, and the moving speed can be freely adjusted on the main slide rail to drive the movement of the hot liquid nozzle. This process can simulate the existence of various background flow fields in actual water bodies.

[0017] Furthermore, the first water tank and the second water tank have the same liquid level height and solution volume, the solute in the first water tank is glycerol, and the solute in the second water tank is potassium dihydrogen phosphate, which are used to generate water bodies with different solution densities but consistent refractive indices.

[0018] Another aspect of the present invention provides a hydrothermal plume experimental method based on a variable background flow field, comprising the following steps:

[0019] a. Install the main slide and electric trolley. Fix the main slide directly above the experimental water tank and keep it level and stable. Then place the electric trolley on the main slide and power on to move the electric trolley to determine the movement stability of the main slide and the electric trolley.

[0020] b. Install the PIV system. Install a fixed slide rail under the water tank, install the laser source of the PIV system on the fixed slide rail under the experimental water tank, adjust the laser surface so that it emits vertically upward, install the thermometer on the fixed slide rail under the water tank, and fix the high-speed camera on the tripod.

[0021] c. Generate a stratified water body. Pour the glycerol solution and potassium dihydrogen phosphate solution into the first water tank and the second water tank respectively, pump the glycerol solution from the first water tank into the second water tank, and after the mixed solution is fully stirred by the stirrer in the second water tank, pump it into the experimental water tank to generate a stratified environment with matching refractive indices.

[0022] d. Fix the main hot liquid pipeline. Use pipe clamps to fix the hot liquid rubber pipe on the electric trolley, install the hot liquid nozzle on the rubber pipe, and install a drag reduction device to make the hot liquid nozzle penetrate a certain distance below the water surface.

[0023] e. Generate hydrothermal fluid. Use a heating water tank to heat the hydrothermal fluid. The fluid is a glycerol solution. Use an internal agitator to heat the liquid evenly. Use a bypass pipe to pre-discharge a certain volume of hydrothermal fluid and preheat the rubber hose of the main hydrothermal pipeline. Use a T-type thermocouple to measure the bypass pipe outflow temperature. When the fluid outflow temperature is consistent with the hot liquid temperature of the heating water tank, open the third water outlet valve. When the fluid outflow reaches the nozzle, move the electric trolley at the same time to drive the hydrothermal nozzle to move. The movement speed should be maintained at a constant value.

[0024] f. Use the PIV system to observe and record the movement and morphological changes of the plume in the experimental water tank. The experimental process is completed only after the electric trolley moves to more than half the length of the water tank.

[0025] Furthermore, in step e, in order to be close to the actual situation, the main slide rail should maintain a constant uniform speed.

[0026] Furthermore, the mixed solutions in step c have different densities but the same refractive index.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The hydrothermal plume experimental device and method of the present invention have simple structure, convenient operation, low cost, and good reliability, accuracy and ease of use.

[0029] 2. The purpose of using the electric trolley on the main slide rail to drive the hydrothermal nozzle to move at a constant speed is to simulate the background flow, i.e., lateral flow, that exists in the actual deep-sea environment. The present invention drives the hydrothermal nozzle to move at a constant speed by using the electric trolley. By using the principle of relative velocity, the movement speed of the electric trolley is the velocity of the background flow, but in the opposite direction. Changing the speed of the trolley can also simulate the plume morphology under different background flows. At the same time, in order to avoid the influence of the pipeline and the nozzle on the nearby flow field when they move, the use of a drag reduction device is considered to minimize their influence. This solution can simultaneously simulate the movement of hydrothermal plumes under different lateral flow conditions and stratified water conditions in the actual ocean. Not only does it require low experimental equipment, but it is also easy to operate and has low observation difficulty.

[0030] 3. The purpose of spraying the hydrothermal nozzle from top to bottom is to simulate the lateral flow and reduce the cost of experimental equipment. As long as the density of the fluid ejected from the hydrothermal nozzle is greater than the density of the water body around the nozzle, the combined force of buoyancy and gravity is downward, which is consistent with the direction of the plume movement of the nozzle. Therefore, as long as the combined force of the plume and the direction of the plume movement are consistent, it can be shown that the physical and dynamic nature of the plume is the same as that of the actual hydrothermal plume. At the same time, the density of the inflow fluid of the nozzle is less than the density of the bottom layer of the stratified water body in the water tank, in order to prevent the plume from touching the bottom of the water tank during movement, affecting its morphology and observation.

[0031] 4. The purpose of generating stratified water is to simulate the stratification phenomenon caused by temperature and salinity differences in the actual marine environment. By keeping the liquid levels of the two water tanks at the same height and the solution volume consistent, a stable stratified water body can be generated through the "double cylinder method". In order to avoid image blur and noise problems during PIV measurement caused by the difference in refractive index of stratified water solutions, glycerol solution / potassium dihydrogen phosphate solution with the same refractive index and different density can be selected to solve the error problem caused by image processing.

[0032] 5. The PIV particle image velocimetry technology can be used to clearly record the particle's motion trajectory and real-time position image. The PIV system and thermometer can simultaneously obtain the velocity field and temperature field of the plume. The S60 hollow glass microbead tracer particle used has a density close to that of water, and has excellent tracking, uniformity, and signal-to-noise ratio, which can minimize the error.

[0033] 6. In order to ensure that the density of the inflow fluid is greater than the density of the upper environmental water body, the present invention selects glycerol solution as the hydrothermal plume supplementary fluid in the experiment. The supplementary fluid is heated at a constant temperature using a heating water tank. Before the experiment, the hydrothermal fluid outflow pipeline is preheated to reduce the heat loss of the supplementary fluid in the subsequent pipeline transmission, control the outflow fluid temperature to be as consistent as possible with the expected temperature, and improve the experimental accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the present invention;

[0035] Figure 2 It is the right view of the present invention.

[0036] Among them, 1 is the first water tank, 2 is the second water tank, 3 is the water tank agitator, 4 is the water pipe, 5 is the first water outlet valve, 6 is the second water outlet valve, 7 is the outflow device, 8 is the experimental water tank, 9 is the temperature meter, 10 is the laser source, 11 is the hot liquid nozzle, 12 is the drag reduction device, 13 is the hot liquid main pipeline, 14 is the bypass valve, 15 is the bypass pipe, 16 is the third water outlet valve, 17 is the heating water tank, 18 is the variable speed slide rail, 19 is the pipe clamp, 20 is the electric trolley, and 21 is the high-speed camera. DETAILED DESCRIPTION

[0037] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0038] like Figure 1 The figure shows a schematic diagram of a hydrothermal plume experimental device under a variable background flow field according to the present invention. The device specifically comprises a stratified water body generating device composed of a first water tank 1, a second water tank 2, a water tank agitator 3, a first water outlet valve 5, a second water outlet valve 6 and a flow outlet device 7, a PIV system composed of a temperature meter 9, a laser source 10, and a high-speed camera 21, and an environmental background flow field simulation system composed of a main slide rail 18, a pipe clamp 19, an electric trolley 20 and a drag reduction device 12.

[0039] A water pipe 4 and a first water outlet valve 5 are provided at the lower part of the first water tank 1, and the first water outlet valve 5 is connected to the second water tank 2 through the water pipe 4; the second water tank 2 is provided with a water tank agitator 3, and a second water outlet valve 6 is provided at the lower part of the second water tank 2, and the second water outlet valve 6 is connected to the bottom of the experimental water tank 8 through a water pipe, and a flow outlet device 7 is provided at the bottom. The main slide rail 18 is horizontally mounted above the experimental water tank 8, and the electric trolley 20 is placed on the main slide rail 18, and is connected to the hot liquid main pipeline 13 through the pipe clamp 19. The moving speed can be adjusted on the main slide rail 18 to drive the hot liquid nozzle 11 to move, and a drag reduction device 12 connected to the hot liquid nozzle 11 is provided in the moving direction. The hot liquid plume generating device is composed of the hot liquid main pipeline 13, bypass valve 14, bypass pipe 15 and third water outlet valve 16 equipped with the heating water tank 17.

[0040] The experimental water tank 8 is made of a transparent acrylic plate with good light transmittance. The PIV system is mainly composed of a laser source 10, a high-speed camera 18 and a thermometer 9. In the experiment, the main slide rail 18 should be fixed horizontally above the experimental water tank 8. The electric trolley 20 is placed on the main slide rail 18 to drive the hot liquid nozzle 11 to move. The drag reduction device 12 is made of polyethylene and has a conical design. The heating water tank 17 heats the hot liquid fluid. The temperature sensor uses a T-type thermocouple and the heating equipment uses a heating rod. Heat until the fluid outlet temperature is consistent with the hot liquid temperature of the heating water tank, open the third water outlet valve 13, and when the fluid outflow reaches the nozzle, release the electric trolley 20 at the same time to drive the hot liquid nozzle 11 to move. The movement speed should be maintained at a constant value.

[0041] Preferably, the hydrothermal nozzle should be inserted 3-10 cm underwater.

[0042] Preferably, the density of the hydrothermal fluid should be slightly greater than the density of the water around the hydrothermal nozzle and slightly less than the density of the water at the bottom of the experimental water tank.

[0043] Preferably, the main slide rail should be fixed horizontally above the water tank, and the electric trolley should drive the hot liquid nozzle to move at a uniform speed, the moving speed should not exceed 20 cm / s, and the distance between the pipe clamp and the hot liquid nozzle should not exceed 30 cm.

[0044] Preferably, the hot liquid outlet pipe should be a rubber hose, and a portion of the hose should be reserved when the electric vehicle is moving.

[0045] Preferably, the drag reduction device is made of polyethylene and has a streamlined design.

[0046] Preferably, the first water tank and the second water tank need to have the same liquid level height and the same solution volume. The first water tank preferably uses a glycerol solution, and the second water tank preferably uses a potassium dihydrogen phosphate solution.

[0047] Preferably, the heating water tank is equipped with a temperature control sensor, a temperature control switch and a heating device, and is connected to the hot liquid nozzle via a rubber tube.

[0048] As a preferred experimental tracer particle, hollow glass microspheres with a density of 1.10 g / cm 3 , with the characteristics of uniformity and good followability.

[0049] Accordingly, the method for conducting a hydrothermal plume experiment under a variable background flow field using the above device mainly includes the following steps:

[0050] (1) Install the main slide rail 18 and the electric trolley 20. Fix the main slide rail 18 directly above the experimental water tank 8 and keep the main slide rail 18 horizontal and stable. Then place the electric trolley 20 on the main slide rail 18 and power on the electric trolley 20 to move it to determine the movement stability of the main slide rail 18 and the electric trolley 20.

[0051] (2) Install the PIV system. Install a fixed slide rail under the water tank, install the laser source 10 of the PIV system on the fixed slide rail under the experimental water tank 8, adjust the laser surface so that it emits vertically upward, install the temperature meter 9 on the fixed slide rail under the water tank, and fix the high-speed camera 21 on a tripod.

[0052] (3) Generate a stratified water body. Pour the glycerol solution and the potassium dihydrogen phosphate solution into the first water tank 1 and the second water tank 2 respectively, pump the glycerol solution from the first water tank 1 into the second water tank 2 through the first outlet valve 5, and after the mixed solution is fully stirred by the stirrer 3 in the second water tank 2, pump the mixed solution into the experimental water tank through the second outlet valve 6 to generate a stratified environment with a consistent refractive index. The outflow device 7 is far away from the PIV measurement range to reduce the impact of the outflow process on the stratification degree of the observation area. Use a sampling plate to extract solution samples at different depths in the linear stratification environment of the experimental water tank 8, and calibrate the refractive index and stratification degree of the samples.

[0053] (4) Fix the hot liquid main pipeline 13. Use the pipe clamp 19 to fix the hot liquid rubber pipe on the electric trolley 20, install the hot liquid nozzle 11 on the rubber pipe, and install the drag reduction device 12 to make the hot liquid nozzle 11 go deep below the water surface.

[0054] (5) Preparation of hydrothermal fluid. Use a heating water tank 17 to heat the hydrothermal fluid, and control the liquid density to be slightly greater than the density of the water around the hydrothermal nozzle and slightly less than the density of the water at the bottom of the experimental water tank; use an internal agitator to heat the liquid evenly; use a bypass pipe 15 to pre-discharge a certain volume of hydrothermal fluid and preheat the rubber hose of the hydrothermal main pipeline 13; use a T-type thermocouple to measure the outflow temperature of the bypass pipe 15, and when the fluid outflow temperature is consistent with the hot liquid temperature of the heating water tank, close the bypass pipe 15, open the third water outlet valve 13, and turn on the electric trolley 20 at the same time to drive the hydrothermal nozzle 11 to move, and the movement speed should be maintained at a constant value.

[0055] (6) The PIV system is used to observe and record the movement and morphological changes of the plume in the experimental water tank 8. The experimental process is ensured to end only after the electric trolley 20 moves to more than half the length of the water tank.

[0056] In summary, the present invention can well simulate the plume morphology in the actual environmental background flow field. The plume fluid in the stratified environment prepared by the experimental device and method is stable, and the fluid flows out from the upper part of the water tank, which greatly reduces the experimental cost and complexity. At the same time, the method also takes into account the refractive index matching problem of PIV images, making the plume flow field observation clear and reducing the difficulty of experimental data processing and analysis.

Claims

1. A hydrothermal plume experimental device based on a variable background flow field, Features: include An environmental background flow field simulation system composed of a main slide rail (18), a pipe clamp (19), an electric trolley (20) and a drag reduction device (12); A PIV observation system consisting of a temperature meter (9), a laser source (10) and a high-speed camera (21); A stratified water body generating device composed of a first water tank (1), a second water tank (2), a water tank agitator (3), a water pipe (4), a first water outlet valve (5), a second water outlet valve (6) and an outflow device (7); A hydrothermal plume generating device composed of a heating water tank (17), a hydrothermal main pipeline (13), a bypass valve (14), a bypass pipe (15) and a third water outlet valve (16); The main slide rail (18) is mounted horizontally above the experimental water tank (8), and the electric trolley (20) is placed on the main slide rail (18) and connected to the hydrothermal main pipeline (13) via a pipe clamp (19). The moving speed can be adjusted on the main slide rail (18) to drive the hydrothermal spray head (11) located in the water tank to move, so as to simulate the background flow existing in the actual deep-sea environment. A drag reduction device (12) connected to the hydrothermal spray head (11) is provided in the moving direction; the hydrothermal spray head (11) is connected to the hydrothermal plume generating device; The density of the solution in the hydrothermal plume generating device is greater than the density of the water around the hydrothermal nozzle (11) and less than the density of the water at the bottom of the experimental water tank (8); The first water tank (1) and the second water tank (2) have the same liquid level height and the same solution volume. The solute in the first water tank (1) is glycerol, and the solute in the second water tank (2) is potassium dihydrogen phosphate, which are used to generate water bodies with different solution densities but the same refractive index.

2. A hydrothermal plume experimental device based on a variable background flow field according to claim 1, Features: The hydrothermal spray head (11) can freely adjust the depth of penetration into the water surface, and the cross section of the hydrothermal spray head (11) nozzle is circular or elliptical.

3. A hydrothermal plume experimental device based on a variable background flow field according to claim 1, Features: The drag reduction device (12) is conical or streamlined.

4. A hydrothermal plume experimental device based on a variable background flow field according to claim 1, Features: The electric trolley (20) is connected to the hot liquid main pipeline (13) via the pipe clamp (19), and can freely adjust the moving speed on the main slide rail (18) to drive the hot liquid nozzle (11) to move. This process can simulate the situation where a background flow field exists in an actual water body.

5. A hydrothermal plume experimental method based on a variable background flow field, Features The following steps are involved: a. Install the main rail (18) and the electric trolley (20): fix the main rail (18) directly above the experimental water tank (8), and keep the main rail (18) horizontal and stable, then place the electric trolley (20) on the main rail (18), and power on the electric trolley (20) to move to determine the movement stability of the main rail (18) and the electric trolley (20); b. Install the PIV system: install a fixed slide rail under the water tank, install the laser source (10) of the PIV system on the fixed slide rail under the experimental water tank (8), adjust the laser surface so that it emits vertically upward, install the temperature meter (9) on the fixed slide rail under the water tank, and fix the high-speed camera (21) on the tripod; c. Generating a stratified water body: pouring a glycerol solution and a potassium dihydrogen phosphate solution into a first water tank (1) and a second water tank (2) respectively, pumping the glycerol solution from the first water tank (1) into the second water tank (2), and after the mixed solution is fully stirred by the stirrer (3) in the second water tank (2), pumping it into the experimental water tank (8) to generate a stratified environment with matching refractive indices; d. Fixing the hot liquid main pipeline (13): Use the pipe clamp (19) to fix the hot liquid rubber pipe on the electric trolley (20), install the hot liquid nozzle (11) on the rubber pipe, and install the drag reduction device (12) so that the hot liquid nozzle (11) penetrates a certain distance below the water surface; e. Generating a hydrothermal fluid: using a heating water tank (17) to heat the hydrothermal fluid, the fluid is selected from a glycerol solution, and using an internal agitator to heat the liquid evenly; using a bypass pipe (15) to pre-discharge a certain volume of the hydrothermal fluid, and preheating the rubber hose of the hydrothermal main pipeline (13); using a T-type thermocouple to measure the outflow temperature of the bypass pipe (15), until the outflow temperature of the fluid is consistent with the hydrothermal temperature of the heating water tank, open the third water outlet valve (16), and when the fluid outflow reaches the nozzle, simultaneously move the electric trolley (20) to drive the hydrothermal nozzle (11) to move, and the movement speed should be maintained at a constant value; f. The PIV system is used to observe and record the movement and morphological changes of the plume in the experimental water tank (8). The experimental process is ensured to end only after the electric trolley (20) moves to more than half the length of the water tank.

6. A hydrothermal plume experimental method based on a variable background flow field according to claim 5, Features: In step e, the main slide rail (18) should maintain constant uniform motion.

7. A hydrothermal plume experimental method based on a variable background flow field according to claim 5, Features: The mixed solutions in step c have different densities but the same refractive index.

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