Warm salt density rapid layering method

Abstract

The invention relates to the technical field of environment reconstruction, in particular to a temperature-salt density rapid layering method which comprises the following steps: step 1, determining a temperature-salt density layering profile according to the experimental depth of a laboratory pool; 2, calculating a spring layer ratio = h1 / h according to the thickness of the upper-layer fluid and the lower-layer fluid; 3, according to the spring layer ratio, a first refrigeration pipeline needing refrigeration in the laboratory pool from top to bottom is determined; 4, based on the first refrigeration pipeline needing refrigeration, seawater in the seawater pool is injected into the laboratory pool through a water pump according to the spring layer ratio; 5, a spring layer water injection mechanism is arranged at the water injection depth position for water injection, and density layering is completed; sixthly, the temperature of the refrigeration pipeline is controlled through the layered cooling technology, and an expected water layer temperature profile is achieved; by effectively combining the technologies of realizing rapid density layering through spring layer water injection and realizing temperature layering through pool side wall cooling, the temperature-salt density layering condition of an actual ocean can be rapidly simulated at the same time.

Description

Technical Field

[0001] This invention relates to the field of environmental remodeling technology, and specifically to a rapid stratification method for temperature, salinity, and density. Background Technology

[0002] Against the backdrop of global ocean development continuously advancing into the deep sea, deep-sea engineering equipment serves as a crucial support for building a maritime power, and its technological level and innovation capabilities directly impact the effectiveness of the national maritime strategy. Various new energy technologies, such as large wind turbines, energy storage technologies, smart grids, power batteries, hydrogen fuel cells, new energy hydrogen production, and carbon capture, have become the most active areas of technological innovation. Meanwhile, nearshore aquaculture has become excessively intensive, causing serious pollution to the marine environment. The shift from small-scale, nearshore aquaculture to large-scale, intelligent, and industrialized deep-sea aquaculture plus other technologies is an inevitable trend for the future development of marine fisheries.

[0003] In the deep-sea environment, the stratification of seawater (temperature, salinity, and density) is significant, posing severe challenges to the design, testing, and application of deep-sea equipment. Particularly in key sea areas such as the South China Sea, complex ocean phenomena such as internal solitary waves and abnormal waves occur frequently. These phenomena not only affect the safety of deep-sea equipment but also significantly impact its operational efficiency. For example, the horizontal shear flow induced by internal solitary waves during propagation can generate enormous impact forces on offshore structures and even cause serious accidents such as depth drops in submarines and other underwater vehicles.

[0004] To accurately simulate the extremely complex deep-sea environment and improve the research, development, and testing capabilities of deep-sea equipment, domestic and international research institutions have been constructing experimental facilities such as density stratification flumes. my country has achieved significant research results on the generation mechanisms and evolution of body waves and vortices in underwater navigation systems. However, due to the relatively small main scale of the flumes, key indicators such as density stratification parameters and Freud numbers are difficult to replicate in the actual marine environment, resulting in significant scale effects in model test results that cannot be directly applied to practical engineering.

[0005] Therefore, this invention provides a rapid thermo-salinity-density stratification method, which effectively combines rapid density stratification achieved by injecting water into a stratified layer with temperature stratification achieved by cooling the sidewalls of a laboratory water tank, thereby simultaneously and rapidly simulating the thermo-salinity-density stratification of the actual ocean. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a rapid thermo-salinity-density stratification method, which effectively combines rapid density stratification achieved by injecting water into a stratified layer with temperature stratification achieved by cooling the sidewalls of a laboratory water tank. This method can simultaneously and rapidly simulate the thermo-salinity-density stratification of the actual ocean.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: a rapid stratification method for temperature-salinity density, comprising the following steps:

[0008] Step 1: Determine the thermo-salinity-density stratification profile based on the experimental depth of the laboratory pool, and calculate the buoyancy frequency profile of the thermo-salinity-density stratification profile; based on the buoyancy frequency profile curve, determine the coordinates of the horizontal layer at the water surface where the maximum buoyancy frequency is located, and use the coordinates as the interface of the thermo-salinity-density stratified fluid to calculate the thickness of the upper and lower fluid layers.

[0009] Step 2: Calculate the interlayer ratio = h1 / h based on the thickness of the upper and lower fluid layers, where h1 is the thickness of the upper fluid layer and h is the water depth. Using the similarity of the interlayer ratio as the criterion, the water depth and the thickness of the upper fluid layer in the laboratory pool are determined through calculation and analysis.

[0010] Step 3: Based on the tiered ratio, determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank; arrange the cooling pipes around the perimeter of the laboratory water tank, number the cooling pipes arranged from top to bottom in the laboratory water tank, and determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank by the numbering order; determine the temperature of the refrigerant in each cooling pipe according to the actual temperature profile, and use stratified cooling technology to achieve the expected water layer temperature profile.

[0011] Step 4: Based on the first cooling pipe that needs to be cooled in the laboratory water tank, according to the floor-to-floor ratio, arrange the floor-to-floor water injection mechanism at the water injection depth position, and inject seawater from the seawater tank into the laboratory water tank through a water pump, so that the water surface of the laboratory water tank is aligned with the center position of the first cooling pipe that needs to be cooled.

[0012] Step 5: Then, use the interlayer water injection mechanism to inject water at the water injection depth position, so that the interface position of the temperature-salt-density stratified fluid corresponding to the current water injection depth position is consistent with the center position of the first refrigeration pipe that needs to be refrigerated, thus completing the density stratification.

[0013] Step 6: Use stratified cooling technology to control the temperature of the refrigeration pipes to achieve the expected water layer temperature profile and perform temperature stratification.

[0014] Furthermore, in steps one through six, the freshwater pool is located above the laboratory water pool, and the seawater pool is located below the laboratory water pool. The reference depth above the laboratory water pool is used as the reference plane, and the distance from the base plane to the water surface, the refrigeration pipes, and the interlayer water injection mechanism is used as the reference.

[0015] Furthermore, in step three, the steps for determining the first cooling pipe that needs to be cooled from top to bottom in the laboratory water tank are as follows: if the height difference between the center of the current cooling pipe and the control depth meets the thickness requirement of the upper fluid, then the current cooling pipe is selected as the first cooling pipe that needs to be cooled; if the height difference of the current cooling pipe does not meet the thickness requirement of the upper fluid, then the cooling pipe above the current cooling pipe is selected as the first cooling pipe that needs to be cooled.

[0016] Furthermore, in step three, the center-to-center distance between adjacent pipes is 0.2m.

[0017] Furthermore, in step four, the injected seawater is pre-mixed in a seawater pool to adjust its density to the required level.

[0018] Furthermore, in steps one to six, the multi-level water injection mechanism includes a fixed frame, a support mechanism for adjusting the water injection depth position is provided at the top of the fixed frame, and several water injectors are fixedly connected to the bottom of the fixed frame. Each water injector is connected to an inlet pipe and a distribution pipe, and each distribution pipe is connected to a solenoid regulating valve. The solenoid regulating valve is electrically connected to a controller.

[0019] The controller is used to control the opening and closing of the electromagnetic regulating valve based on the water injection depth position to regulate the delivery flow rate.

[0020] Furthermore, in steps one through six, the multi-level water injection mechanism also includes a heating module, which is located at the top of the frame and corresponds to the position of the water injector.

[0021] Furthermore, in steps three to six, the first refrigeration pipe that needs to be cooled is used as a reference pipe to obtain the temperature of the refrigerant in each refrigeration pipe above the reference pipe, as well as the expected salt density and interface height of the temperature-salt-density stratified fluid.

[0022] The heating temperature of the heating module is adjusted according to the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile. Then, the corresponding cooling pipe number is obtained according to the interface height. The cooling pipe on one side of the laboratory pool is adjusted according to the heating temperature, and the cooling pipe on the other side is set according to the expected temperature profile.

[0023] Furthermore, in steps one through six, the adjustment method of the heating module uses the nonlinear relationship between water temperature and density as a reference, and then makes corrections based on the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile.

[0024] Furthermore, in steps three to six, the layer number of the corresponding refrigeration pipe below is obtained based on the interface of the temperature-salt-density stratified fluid, and the refrigeration pipe is adjusted according to the rated temperature based on the layer number.

[0025] Furthermore, in steps three through six, the rated temperature corresponding to the refrigeration pipes with layered numbering is 4°C.

[0026] Furthermore, in steps one through six, temperature sensors evenly distributed along the water depth will be used to measure and analyze the temperature characteristics in the water depth direction.

[0027] Furthermore, in steps one through six, during the process of injecting water into the freshwater tank through the interlayer water injection mechanism, the freshwater tank will be continuously replenished to maintain the freshwater level in the tank.

[0028] The above approach has the following beneficial effects:

[0029] 1. This solution treats the water body through a stepped water injection mechanism and a temperature stratification method to ensure the accuracy of the thermo-salinity-density stratification interface, so as to facilitate the rapid establishment of thermo-salinity-density stratified fluid.

[0030] 2. This solution utilizes a heating module to heat the surrounding freshwater and seawater mixture, causing the mixture to gradually float to the surface of the seawater due to its density, thus facilitating the rapid formation of the upper fluid layer and improving the speed of stratification.

[0031] 3. This scheme achieves salinity maintenance by forming a high-density seawater layer at the interface of the thermo-salinity-density fluid. The high-salinity water body reduces water flow and decreases heat transfer between the upper and lower layers, thereby reducing density interference between the upper and lower layers during heating and facilitating temperature stratification.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of an embodiment of the rapid stratification method for temperature-salt density of the present invention;

[0034] Figure 2 This is a schematic diagram of the laboratory water tank layout in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0035] Figure 3 This is a schematic diagram showing the design of temperature measuring point locations in an embodiment of the rapid stratification method for temperature-salt density of the present invention;

[0036] Figure 4 This is a schematic diagram of the water depth temperature distribution at measuring points 1, 6, 7, 14, and 15 in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0037] Figure 5This is a schematic diagram of the water depth temperature distribution at measuring points 2, 5, 9, 13, and 16 in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0038] Figure 6 This is a schematic diagram of the water depth temperature distribution at measuring points 3, 4, 11, 12, and 17 in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0039] Figure 7 This is a schematic diagram of the water depth temperature distribution at measuring points 7 to 11 in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0040] Figure 8 This is a temperature profile diagram of six open circulation tubes and an internal temperature of 5 degrees Celsius in an embodiment of the rapid stratification method for temperature-salt-density density of the present invention.

[0041] Figure 9 This is a cross-sectional view of the buoyancy frequency when six circulation tubes are open and the temperature inside the tubes is 5 degrees Celsius, according to an embodiment of the rapid stratification method of temperature-salt-density of the present invention.

[0042] Figure 10 This is a temperature profile diagram of six open circulation tubes and an internal temperature of 10 degrees Celsius in an embodiment of the rapid stratification method for temperature-salt-density density of the present invention.

[0043] Figure 11 This is a cross-sectional view of the buoyancy frequency when six circulation tubes are open and the temperature inside the tubes is 10 degrees Celsius, according to an embodiment of the rapid stratification method for temperature-salt-density density of the present invention.

[0044] Figure 12 This is a temperature profile diagram of four open circulation tubes and an internal temperature of 10 degrees Celsius in an embodiment of the rapid stratification method for temperature-salt-density density of the present invention.

[0045] Figure 13 This is a cross-sectional view of the buoyancy frequency when four circulation tubes are open and the temperature inside the tubes is 10 degrees Celsius, according to an embodiment of the rapid stratification method for temperature-salt-density density of the present invention.

[0046] Figure 14 This is a schematic diagram of the refrigeration pipe structure arrangement in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention;

[0047] Figure 15 This is a partial connection diagram of the refrigeration pipe structure in an embodiment of the rapid stratification method for temperature, salinity, and density of the present invention.

[0048] The reference numerals in the accompanying drawings include: 1. Freshwater tank; 2. Fixed frame; 3. Seawater tank; 4. Water injector. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The following detailed description illustrates the specific implementation method:

[0051] As attached Figures 1 to 3 As shown: A rapid stratification method for thermo-salinous-density fluids includes the following steps: Step 1: Determine the thermo-salinous-density stratification profile based on the experimental depth of the laboratory water tank, and calculate the buoyancy frequency profile of the thermo-salinous-density stratification profile; Based on the buoyancy frequency profile curve, determine the coordinate value of the horizontal layer at the water surface where the maximum buoyancy frequency is located, and use the coordinate value as the interface of the thermo-salinous-density stratified fluids to calculate the thickness of the upper and lower fluid layers.

[0052] Step 2: Calculate the layer ratio = h1 / h based on the thickness of the upper and lower fluid layers, where h1 is the thickness of the upper fluid layer and h is the water depth. Using the similarity of the layer ratio as the criterion, the water depth and the thickness of the upper fluid layer in the laboratory pool are determined through calculation and analysis.

[0053] Step 3: Based on the tiered ratio, determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank; arrange the cooling pipes around the perimeter of the laboratory water tank, number the cooling pipes arranged from top to bottom in the laboratory water tank, and determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank by the numbering order; determine the temperature of the refrigerant in each cooling pipe according to the actual temperature profile, and use stratified cooling technology to achieve the expected water layer temperature profile.

[0054] In this embodiment, the center of the first refrigeration pipe is located 0.1m below the control depth (0m) plane, and then the center distance between every two refrigeration pipes is 0.2m, for a total of 30 pipes.

[0055] The steps to determine the first cooling pipe that needs to be cooled from top to bottom in the laboratory water tank are as follows: If the height difference between the center of the current cooling pipe and the control depth meets the thickness requirement of the upper fluid, then the current cooling pipe is selected as the first cooling pipe that needs to be cooled. If the height difference of the current cooling pipe does not meet the thickness requirement of the upper fluid, then the cooling pipe above the current cooling pipe is selected as the first cooling pipe that needs to be cooled.

[0056] For example, if pipe number ② is selected as the first refrigeration pipe, its center position is 0.3m away from the control depth (0m) surface, which does not meet the thickness requirement of the upper fluid. Therefore, pipe number ① needs to be selected as the first refrigeration pipe, meaning that all refrigeration pipes need to be opened during the experiment. Then, based on the actual temperature profile, the temperature of the refrigerant in each refrigeration pipe is determined, i.e., a stratified cooling technique is adopted to achieve the expected temperature profile.

[0057] Step 4: Based on the first cooling pipe requiring cooling in the laboratory water tank, and according to the stratification ratio, the stratification water injection mechanism is positioned at the injection depth. The injected seawater is pre-mixed in seawater tank 3 to adjust its density to the required level. The seawater in seawater tank 3 is then pumped into the laboratory water tank, aligning the water surface of the laboratory water tank with the center of the first cooling pipe requiring cooling. The pre-mixing of seawater ensures the accuracy of the injected seawater, thereby ensuring the accuracy of salt density control at the subsequent density stratification interface.

[0058] Step 5: Then, use the interlayer water injection mechanism to inject water at the injection depth position, so that the interface position of the temperature-salt-density stratified fluid corresponding to the current injection depth position is consistent with the center position of the first refrigeration pipe that needs to be cooled, thus completing the density stratification.

[0059] Step Six: Employ stratified cooling technology to control the temperature of the refrigeration pipes, achieving the desired water layer temperature profile. Temperature stratification is performed, and the schematic diagram of the refrigeration pipe structure layout is shown below. Figure 14 As shown, a technique of stratified cooling of the lower fluid layer by installing refrigerant circulation pipes on the side wall of the water tank is used to achieve stable temperature stratification of the fluid within the laboratory water tank. The entire refrigeration piping system consists of two parts. The first part is the refrigeration piping system of the main body of the laboratory water tank, as follows: Figure 15 The green section shows the components: C is the refrigerant inlet pipe, and D is the refrigerant outlet pipe; the second section is the deep well's refrigeration piping system, as follows. Figure 14 The blue section shows that A is the refrigerant inlet pipe and B is the refrigerant outlet pipe. Figure 15 The copper color (E) indicates the fixed support for the refrigeration pipe.

[0060] The multi-level water injection mechanism includes a fixed frame 2. The top of the fixed frame 2 is equipped with a support mechanism for adjusting the water injection depth. The support mechanism includes a support plate located above the water tank. A roller is fixedly connected to the support plate, and a pull rope is wound on the roller. A roller is rotatably fitted on the top of the fixed frame 2, and the pull rope slides with the roller. Several water injectors 4 are fixedly connected to the bottom of the fixed frame 2. Each water injector 4 is connected to an inlet pipe and a distribution pipe between itself and the freshwater tank 1. Each distribution pipe is connected to an electromagnetic regulating valve, and the electromagnetic regulating valve is electrically connected to a controller. The controller is used to control the opening and closing of the electromagnetic regulating valve based on the water injection depth to adjust the delivery flow rate.

[0061] For example, based on the location of pipe number ① in the water tank, since the distance from the center of pipe ① to the control depth (0m) is 0.10m, 0.15m of fresh water needs to be injected above the control depth (0m) to meet the requirements. Therefore, density stratification is first carried out according to the following scheme.

[0062] Adjust the interlayer water injection mechanism so that the distance from its bottom to the bottom of the laboratory water tank is 4.85m. Use seawater tank 3 to inject seawater into the laboratory water tank through a water pump until the water surface of the laboratory water tank is at the control depth (-0.1m) (the center position of pipe No. 1).

[0063] Then, freshwater from freshwater tank 1 is injected into the laboratory water tank according to the injection depth position using a stepped water injection mechanism. Freshwater is injected into the laboratory water tank through 165 water injectors 4 below the stepped water injection mechanism at a set flow rate until the water surface reaches the control depth (+0.15m). At this time, the water depth in the laboratory water tank is 5.0m, and the distance from the center of pipe No. 1 to the water surface is 0.25m, so that the interface position of the thermo-salinous-density fluid corresponding to the current injection depth position is consistent with the center position of pipe No. 1.

[0064] After density stratification is completed, temperature stratification is performed using the temperature stratification method in step three. At this time, the interface position of the temperature-salt-density stratified fluid in the laboratory water tank should be exactly located at the control depth (-0.1m) surface, that is, the stratification ratio is 1 / 20.

[0065] In this system, freshwater tank 1 is located above the laboratory water tank, and seawater tank 3 is located below it. The reference depth above the laboratory water tank is used as the reference surface, and the distances from the base surface to the water surface, refrigeration pipes, and the tiered water injection mechanism are also used as references. By utilizing the location distribution of freshwater tank 1 and seawater tank 3, freshwater naturally flows into the laboratory water tank due to gravity, facilitating the establishment of density stratification. The establishment of the reference surface provides a baseline for subsequently determining the positions of the water surface, refrigeration pipes, and the tiered water injection mechanism.

[0066] In steps one through six, temperature sensors evenly distributed along the water depth will be used to measure and analyze the temperature characteristics in the water depth direction. Simultaneously, during the water injection process in freshwater tank 1 via the tiered injection mechanism, water will be continuously replenished to maintain the freshwater level in tank 1.

[0067] For example, temperature measurement and analysis can be used to verify the uniformity of the water temperature distribution along the lateral side of the laboratory pool, ensuring the accuracy of temperature stratification. By effectively combining the stratified water injection with the temperature stratification technology of cooling the side walls of the laboratory pool, the temperature, salinity, and density stratification of the actual ocean can be simulated rapidly and simultaneously. Meanwhile, by timely replenishing freshwater pool 1, the liquid level of freshwater in freshwater pool 1 is maintained at all times, thus maintaining the water pressure at the bottom of freshwater pool 1 and ensuring that the outflow rate of water injector 4 remains stable, facilitating the control of freshwater injection.

[0068] In another embodiment, in steps one through six, the layered water injection mechanism further includes a heating module located at the top of the frame, corresponding to the position of the water injector 4. The heating module is adjusted using the non-linear relationship between water temperature and density as a reference, and then corrected based on the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile.

[0069] The heating module heats the surrounding freshwater and seawater mixture. Since the salinity of the surrounding seawater is relatively stable at the current time, the density of the surrounding freshwater and seawater mixture is low. After heating the surrounding freshwater and seawater mixture, the density of the mixture is further reduced, which makes it easier for the mixture to gradually float to the upper layer of the seawater due to its density, so as to facilitate the rapid formation of the upper fluid.

[0070] For example, considering the influence of seawater salt density, the density of ice at 0℃ (917 kg / m³) is less than that of water at 4℃ (1000 kg / m³), so ice floats on the water surface; while the density of water at 20℃ (998 kg / m³) is less than that of water at 4℃, but greater than that of water at 30℃ (995 kg / m³). By using nonlinear relationships as a reference, and then making corrections based on the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile, the upper fluid can be quickly established while reducing the impact on water bodies with different densities.

[0071] In steps three through six, the layer number of the corresponding refrigeration pipe is obtained based on the interface of the thermo-salinity-density stratified fluid. The refrigeration pipe is then adjusted according to its rated temperature based on this layer number. The rated temperature corresponding to the refrigeration pipe with the layer number is 4°C. By forming a high-density seawater layer at the interface of the thermo-salinity-density stratified fluid, the salinity of the seawater layer is maintained. The high salinity of the water reduces water flow and decreases heat transfer between the upper and lower layers, thereby reducing density interference during heating and facilitating temperature stratification.

[0072] For example, since the density of water is at 4°C, the density of water will decrease at temperatures above or below this. Temperature is used to maintain the isolation of high-density interfaces, and the high-density interfaces reduce the flow of water so that the upper water can be dispersed by fresh water. After the original temperature profile is restored, the lower water maintains the original thermo-salinity-density stratification fluid unchanged, thus facilitating rapid thermo-salinity-density stratification.

[0073] In other embodiments, the first cooling pipe requiring cooling is used as a reference pipe. The temperature of the refrigerant in each cooling pipe above the reference pipe, as well as the expected salt density and interface height of the thermosalinity-density stratified fluid, are obtained. The heating temperature of the heating module is adjusted according to the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile. Then, the corresponding cooling pipe number is obtained according to the interface height. The cooling pipe on one side of the laboratory pool is adjusted according to the heating temperature, while the cooling pipe on the other side is set according to the expected temperature profile.

[0074] For example, by adjusting the heating temperature through a cooling pipe on one side, the mixed water on that side moves upward to facilitate the rapid formation of the upper fluid layer, while the cooling pipe on the other side maintains the temperature of the thermo-salinity-density stratified fluid to facilitate the establishment of the expected water layer temperature profile, thereby facilitating rapid thermo-pressure-density stratification.

[0075] The experimental method is as follows:

[0076] First, the cooling process of each refrigeration pipe during the stratified heat exchange is explained. In this embodiment, each refrigeration pipe is a Φ100 316L stainless steel pipe, and all refrigeration pipes are filled with refrigerant (the lowest temperature can reach -230°C). A stainless steel booster pump is used to circulate the refrigerant within the pipes. The refrigerant in the pipes is conducted through the surface of the stainless steel pipes to the laboratory water tank, thereby cooling the seawater in the laboratory water tank. The pipes at the bottom of the laboratory water tank are cooled by an independent refrigeration unit using refrigerant. Every three refrigeration pipes in the laboratory water tank are grouped together and cooled by an independent refrigeration unit using refrigerant. There are a total of 30 refrigeration pipes in the laboratory water tank, requiring a total of 10 refrigeration units.

[0077] Based on the requirement for seawater cooling, it is known that cooling seawater of mass m to a temperature difference... The required heat source for cold source is .

[0078] Where c is the specific heat of solution of seawater (=3.9kJ / (kg)). The mass of seawater in the laboratory pool is m = 110 (length) * 6 (width) + 6 (depth) * 1000 (seawater density) = 3.96 + 106 (kg). The room temperature of the laboratory pool is considered to be the highest temperature in Sanya (set to 28 degrees Celsius). The minimum temperature of the seawater in the laboratory pool drops to 6 degrees Celsius, that is, the temperature difference is 22 degrees Celsius.

[0079] Therefore, Q = 3.4 (J) = 3.3 (kW / s). Let the cooling capacity required by the refrigeration unit to provide heat from this cold source be W, and the time required to cool the seawater in the laboratory pool to 60°C be _____. Then W =Q, therefore W=Q / =8000 (kW). In this embodiment, a total of 10 refrigeration units are used for cooling the seawater in the laboratory pool. Therefore, when selecting refrigeration units, the cooling capacity of each unit only needs to be 1000 (kW). The total cooling capacity of the 10 refrigeration units used in the laboratory pool is W. m =10000 (kW), which translates to an electricity consumption of 2857 (kW / h). In the planning and design of this laboratory, the electricity consumption of the temperature stratification refrigeration unit for the laboratory water tank is 3000 (kW / h), which can meet the electricity demand for cooling the seawater in the laboratory water tank from room temperature to 6 degrees Celsius within 12 hours.

[0080] The refrigeration piping is made of 316L stainless steel tubing with a thermal conductivity coefficient of [missing value]. =1.14 (kW / (m) 2 The area of ​​all refrigeration pipes in the laboratory water tank is S = 2400 (m²). 2 When the temperature difference between the inside and outside of the pipe is The heat exchange efficiency is highest at 8 degrees Celsius, and the actual heat exchange area required at this time is S. m =W m / ( ) = 10000 / (1.14 * 8) = 1096 m 2 Therefore, S>S m That is, the area of ​​the cooling pipes in the laboratory water tank is sufficient to meet the heat dissipation area required to lower the seawater in the laboratory water tank to the required experimental temperature.

[0081] The verification process of temperature stratification technology in ultra-large laboratory water tanks is shown below:

[0082] The basic principle is as follows:

[0083] A preliminary experiment was conducted using a 14m long, 6m wide, and 2.3m deep water tank in a chemical plant. The tank has a steel frame and steel plate wall structure. Along one side of the tank's length, there is a coiled stainless steel refrigeration pipe, with the upper end of the pipe 0.3m from the top of the tank's side wall. The pipe is cooled by a refrigerant chiller unit, thereby cooling the liquid chemical raw materials inside the tank.

[0084] In December 2019, this project conducted experimental research based on this water tank. The water depth in the tank was 2.2m, the temperature of the chilled liquid in the pipes was 0 degrees Celsius, and the water in the tank was tap water with a temperature of 9.7 degrees Celsius. After approximately 10 hours, temperature sensors were used to measure and analyze the temperature characteristics along the water depth at relevant measuring points within the tank. Figure 3 As shown. The temperature sensor was developed by Nanjing University of Science and Technology. The temperature acquisition unit is model CH-WT32-H, which uses a platinum resistance thermometer, has a synchronization accuracy of 10µs, a sampling rate of 1Hz-2KHz, and a resolution of 0.0002℃.

[0085] The measurement results of temperature distribution along the water depth at each measuring point are as follows: Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown in the figure. Among them, measuring points 1, 6-7, and 14-15 are on the same straight line in the transverse direction of the water tank, and the temperature distribution along the water depth direction is as follows. Figure 4 Measuring points 2, 5, 9, 13, and 16 are on the same straight line in the transverse direction of the water tank. The temperature distribution along the water depth direction is as follows: Figure 5 Measuring points 3, 4, 11, 12, and 17 are on the same straight line in the transverse direction of the water tank. The temperature distribution along the water depth direction is as follows: Figure 6 Measuring points 7-11 are on the same straight line along the longitudinal direction of the water tank. The temperature distribution along the water depth direction at these points is as follows: Figure 7 .

[0086] Figure 4 , Figure 5 , Figure 6 and Figure 7 The temperature fluctuation at the same depth at each measuring point was approximately 0.2 degrees Celsius. This indicates that it is technically feasible to maintain a uniform temperature distribution along the lateral side of a 6-m wide laboratory water tank by using the method of cooling the sidewalls of the tank.

[0087] Research on heat stratification technology:

[0088] In 2010, Shanghai Jiao Tong University and the National University of Defense Technology jointly constructed a density-stratified water tank measuring 12m long, 1.2m wide, and 1.0m deep. Subsequently, in 2017, a temperature stratification system was added, realizing temperature stratification technology in a small-scale water tank. The temperature stratification system, consisting of six circulation pipes, one heater, one water pump, and six control valves, is installed on the inner wall of the tank. The operating method is as follows: first, tap water is injected into the stainless steel circulation pipes to fill them. Then, an electric heater heats the tap water in the circulation pipes, and the water pump and corresponding valves control the flow rate of the circulating hot water in the pipes, thereby heating the water in the tank.

[0089] The temperature and buoyancy frequency profiles of the stratified fluid in the water tank were measured when all six circulation pipes were fully open and the temperature inside the pipes was 5 degrees Celsius (e.g., Figure 8 and Figure 9 (As shown). Figure 10 and Figure 11 The results show the temperature and buoyancy frequency profiles of the thermosilicate fluid in the tank when the pipe temperature is 10 degrees Celsius. Figure 12 and Figure 13 This is the result when only the top four circulation pipes are open.

[0090] Based on the above results, it can be seen that the water temperature in the tank can be adjusted by setting the temperature of the heater, and the position of the heating source can be adjusted by controlling six control valves to achieve control of different temperature gradient positions, thus forming the desired temperature stratification profile. This verifies the technical solution of thermo-salinity-density stratification. Specifically, by effectively combining the rapid density stratification technology of rapid water injection with the temperature stratification technology of cooling the sidewall of the laboratory water tank, the actual thermo-salinity-density stratification system of the ocean can be simulated simultaneously and rapidly. Furthermore, by employing a rapid water injection mechanism, the position of the thermo-salinity-density gradient can be adjusted and controlled without changing the water depth, achieving rapid thermo-salinity-density stratification.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rapid stratification method for thermo-salinous density, characterized in that, Includes the following steps: Step 1: Determine the thermo-salinity-density stratification profile based on the experimental depth of the laboratory pool, and calculate the buoyancy frequency profile of the thermo-salinity-density stratification profile; based on the buoyancy frequency profile curve, determine the coordinates of the horizontal layer at the water surface where the maximum buoyancy frequency is located, and use the coordinates as the interface of the thermo-salinity-density stratified fluid to calculate the thickness of the upper and lower fluid layers. Step 2: Calculate the interlayer ratio = h1 / h based on the thickness of the upper and lower fluid layers, where h1 is the thickness of the upper fluid layer and h is the water depth. Using the similarity of the interlayer ratio as the criterion, the water depth and the thickness of the upper fluid layer in the laboratory pool are determined through calculation and analysis. Step 3: Based on the tiered ratio, determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank; arrange the cooling pipes around the perimeter of the laboratory water tank, number the cooling pipes arranged from top to bottom in the laboratory water tank, and determine the first cooling pipe that needs cooling from top to bottom in the laboratory water tank by the numbering order; determine the temperature of the refrigerant in each cooling pipe according to the actual temperature profile, and use stratified cooling technology to achieve the expected water layer temperature profile. Step 4: Based on the first cooling pipe that needs to be cooled in the laboratory water tank, according to the floor ratio, arrange the floor water injection mechanism at the water injection depth position, and inject the seawater in the seawater pool (3) into the laboratory water tank by water pump, so that the water surface of the laboratory water tank is aligned with the center position of the first cooling pipe that needs to be cooled. Step 5: Then, use the interlayer water injection mechanism to inject water at the water injection depth position, so that the interface position of the temperature-salt-density stratified fluid corresponding to the current water injection depth position is consistent with the center position of the first refrigeration pipe that needs to be refrigerated, thus completing the density stratification. Step 6: Use stratified cooling technology to control the temperature of the refrigeration pipes to achieve the expected water layer temperature profile and perform temperature stratification.

2. The rapid stratification method for temperature-salinity density according to claim 1, characterized in that, In steps one through six, the freshwater pool (1) is located above the laboratory pool, and the seawater pool (3) is located below the laboratory pool. The reference depth above the laboratory pool is used as the reference surface, and the distance between the base surface and the water surface, the cooling pipes and the interlayer water injection mechanism is used as the reference.

3. The rapid stratification method for temperature-salinity density according to claim 2, characterized in that, In step three, the steps for determining the first cooling pipe that needs to be cooled from top to bottom in the laboratory water tank are as follows: if the height difference between the center of the current cooling pipe and the control depth meets the thickness requirement of the upper fluid, then the current cooling pipe is selected as the first cooling pipe that needs to be cooled; if the height difference of the current cooling pipe does not meet the thickness requirement of the upper fluid, then the cooling pipe above the current cooling pipe is selected as the first cooling pipe that needs to be cooled.

4. The rapid stratification method for temperature-salinity density according to claim 3, characterized in that, In step three, the center distance between adjacent refrigeration pipes is 0.2m.

5. The rapid stratification method for temperature-salinity density according to claim 4, characterized in that, In step four, the injected seawater is pre-mixed in a seawater pool (3) to adjust the seawater density to the required density.

6. The rapid stratification method for temperature-salinity density according to claim 5, characterized in that, In steps one to six, the multi-layer water injection mechanism includes a fixed frame (2), the top of the fixed frame (2) is provided with a support mechanism for adjusting the water injection depth, and a number of water injectors (4) are fixedly connected to the bottom of the fixed frame (2). The water injectors (4) are connected to the freshwater tank (1) by inlet pipes and distribution pipes, and the distribution pipes are connected to the water injectors (4) by electromagnetic regulating valves. The electromagnetic regulating valves are electrically connected to a controller. The controller is used to control the opening and closing of the electromagnetic regulating valve based on the water injection depth position to regulate the delivery flow rate.

7. The rapid stratification method for temperature-salinity density according to claim 6, characterized in that, In steps one through six, the multi-layer water injection mechanism also includes a heating module, which is located at the top of the frame and corresponds to the position of the water injector (4).

8. The rapid stratification method for temperature-salinity density according to claim 7, characterized in that, In steps three to six, the first refrigeration pipe that needs to be cooled is used as a reference pipe to obtain the temperature of the refrigerant in each refrigeration pipe above the reference pipe, as well as the expected salt density and interface height of the temperature-salt-density stratified fluid. The heating temperature of the heating module is adjusted according to the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile. Then, the corresponding cooling pipe number is obtained according to the interface height. The cooling pipe on one side of the laboratory pool is adjusted according to the heating temperature, and the cooling pipe on the other side is set according to the expected temperature profile.

9. The rapid stratification method for temperature-salinity density according to claim 8, characterized in that, In steps one through six, the heating module is adjusted using the nonlinear relationship between water temperature and density as a reference, and then corrected based on the thermal conductivity corresponding to the current seawater salt density and the actual temperature profile.

10. The rapid stratification method for temperature-salinity density according to claim 9, characterized in that, In steps three through six, the layer number of the corresponding refrigeration pipe below is obtained based on the interface of the temperature-salt-density stratified fluid, and the refrigeration pipe is adjusted according to the rated temperature based on the layer number.

11. The rapid stratification method for temperature-salt density according to claim 10, characterized in that, In steps three through six, the rated temperature corresponding to the refrigeration pipes with layered numbering is 4℃.

12. The rapid stratification method for temperature-salinity density according to claim 11, characterized in that, In steps one through six, temperature sensors uniformly distributed along the water depth are also used to measure and analyze the temperature characteristics in the water depth direction.

13. The rapid stratification method for temperature-salinity density according to claim 12, characterized in that, In steps one through six, during the process of injecting water into the freshwater tank (1) through the interlayer water injection mechanism, water is continuously replenished to maintain the level of freshwater in the freshwater tank (1).

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