Variable cycle ocean liquid-gas flow pressure coupling energy storage device and design method thereof

Abstract

The application provides a variable cycle marine liquid-gas flow pressure coupling energy storage device and a design method thereof, relates to the technical field of energy storage devices, and provides the variable cycle marine liquid-gas flow pressure coupling energy storage device, which comprises a water storage tank, a generator set, a valve and a water pump. The bottom of the water storage tank is provided with a water outlet pipe, the top of the water storage tank is provided with a water inlet channel and a vent group for communicating with an external space; the valve and the generator set are both installed on the water inlet channel, the valve is located above the generator set and is configured to control the on-off of the water inlet channel; and the water pump is installed at the pipe opening of the water outlet pipe. The variable cycle marine liquid-gas flow pressure coupling energy storage device can effectively solve the problem of air pressure resistance in the water filling and discharging process of the water storage tank, and can greatly improve the seawater energy storage and conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a variable circulation marine liquid gas-pressure coupled energy storage device and its design method. Background Technology

[0002] With the continued advancement of industrialization and the significant increase in energy demand driven by artificial intelligence technology, the global energy structure is accelerating its transition towards cleaner and renewable energy sources. This has led to a continuous expansion of grid-connected renewable energy sources such as wind and solar power, which are characterized by intermittency and volatility. The power generation output of these energy sources is highly dependent on natural conditions, exhibiting significant instability and uncontrollability, posing a severe challenge to grid stability, frequency regulation, and real-time power supply and demand balance. Therefore, developing large-scale, high-efficiency, and highly reliable energy storage technologies has become crucial for achieving efficient renewable energy utilization and constructing new power systems.

[0003] Currently, the mainstream large-scale energy storage technologies mainly include three categories: pumped hydro storage, compressed air storage, and electrochemical energy storage. Among them:

[0004] 1. Pumped storage, as the most mature and largest capacity energy storage method at present, is subject to special geographical conditions (reservoirs with elevation differences are required), and has limitations such as difficulty in site selection, long construction period, and high initial investment cost. In addition, it may have a negative impact on the ecological environment. These factors greatly restrict its promotion and application.

[0005] 2. Compressed air energy storage also has high requirements for geological conditions (it needs to rely on specific geological structures such as salt caverns or abandoned mines), and traditional systems need to rely on fossil fuels for supplemental combustion, which is insufficient in terms of cleanliness.

[0006] 3. Although electrochemical energy storage (represented by lithium-ion batteries) has advantages such as flexible deployment and rapid response, it still faces challenges such as high cost, limited cycle life, thermal runaway safety risks, and waste battery recycling when applied on a large scale.

[0007] Liquid potential energy storage, based on the bidirectional circulation and pressure coupling of deep ocean seawater and air, is a novel energy storage technology that effectively utilizes ocean resources to store energy. However, this technology still faces several key technical challenges:

[0008] 1. Energy storage capacity limitation: The energy storage capacity of conventional energy storage tanks is significantly smaller than that of traditional land-based reservoir pumped storage schemes. If the volume of the energy storage tank is increased, the difficulty of underwater construction will increase dramatically.

[0009] 2. Pressure regulation problem: During the filling process, the gas inside the tank creates positive pressure resistance; during the draining process, negative pressure resistance is generated. The change in pressure directly affects the filling and draining efficiency, and thus affects the energy conversion and storage efficiency.

[0010] 3. Fluid resistance problem: Submarine tanks usually adopt a bottom filling and emptying design. During the filling process, as the water level rises, the water inlet resistance continues to increase, which also restricts the improvement of energy conversion and storage efficiency. Summary of the Invention

[0011] The purpose of this invention is to provide a variable circulation marine liquid gas-pressure coupling energy storage device and its design method, which abandons the design idea of ​​simply relying on increasing the volume of the water tank to increase energy storage, and can improve energy conversion and storage efficiency.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] In a first aspect, the present invention provides a variable circulation marine liquid-gas-pressure coupling energy storage device, comprising a water storage tank, a generator set, valves and a water pump;

[0014] The bottom of the water storage tank is provided with a water outlet pipe, and the top of the water storage tank is provided with a water inlet channel and a group of vents for communicating with the external space.

[0015] Both the valve and the generator set are installed in the water inlet channel. The valve is located above the generator set and is configured to control the opening and closing of the water inlet channel.

[0016] The water pump is installed at the outlet of the water pipe.

[0017] In an optional embodiment, the vent group includes a buffer tank vent, and the variable circulation marine liquid gas-pressure coupling energy storage device further includes an air buffer tank, which is connected to the buffer tank vent via a connecting pipe.

[0018] In an optional embodiment, multiple water storage tanks are configured, and the vent holes of the buffer tanks of each water storage tank are connected to the air buffer tank through the connecting pipe.

[0019] In an optional embodiment, the top of the air buffer tank is connected to a buffer tank inlet / outlet pipe, one end of which is connected to the internal space of the air buffer tank, and the other end is connected to the atmosphere and is provided with a first shielding cover.

[0020] In an optional embodiment, the end of the air inlet / outlet pipe of the buffer tank near the air buffer tank is connected to a plurality of first inclined cables, and the end of each first inclined cable away from the air inlet / outlet pipe of the buffer tank is configured to be connected to the seabed foundation.

[0021] And / or, the end of the air inlet / outlet pipe of the buffer tank away from the air buffer tank is connected to a first float, the first float being configured to be located below the water surface.

[0022] In an optional embodiment, the vent assembly includes an atmospheric vent, and the top of the water tank is connected to a water tank inlet / outlet pipe. One end of the water tank inlet / outlet pipe is connected to the atmospheric vent, and the other end is connected to the atmosphere and is provided with a second shielding cover.

[0023] In an optional embodiment, the end of the air inlet / outlet pipe of the water storage tank near the water storage tank is connected to a plurality of second stay cables, and the end of each second stay cable away from the air inlet / outlet pipe of the water storage tank is configured to be connected to the seabed foundation.

[0024] And / or, the end of the air inlet / outlet pipe of the water tank away from the water tank is connected to a second float, the second float being configured to be below the water surface.

[0025] In an optional embodiment, the bottom of the water storage tank is provided with a counterweight, and / or the water storage tank is provided with an inspection door.

[0026] Secondly, the present invention provides a design method for a variable-circulation marine fluid-gas-pressure coupled energy storage device, used to design the variable-circulation marine fluid-gas-pressure coupled energy storage device as described in any of the foregoing embodiments, comprising:

[0027] Formula for the water flow velocity at the outlet of the water inlet channel in the water storage tank when no air buffer tank is installed;

[0028] When it is determined that no air buffer tank is installed and the air inlet and outlet pipes of the water storage tank are vented, the inlet velocity formula and the outlet velocity formula of the air inlet and outlet pipes of the water storage tank are as follows:

[0029] Based on the water flow velocity formula and the inlet flow velocity formula, establish the first set of air pressure balance equations for the water storage tank when no air buffer tank is installed;

[0030] The second set of pressure balance equations for the water storage tank when the air buffer tank is set is obtained based on the first set of pressure balance equations.

[0031] In an optional implementation, it includes:

[0032] The formula for determining the water flow velocity is as follows:

[0033]

[0034] in, P w The liquid pressure at the inlet of the water inlet channel is [value missing]. P at The gas pressure inside the water storage tank.λ The coefficient of friction of the inner wall of the water inlet channel. ρ w For water density, L w The length of the water inlet channel, d w The diameter of the water inlet channel is [missing information]. v wt The water flow velocity at the outlet;

[0035] The inlet velocity formula and the outlet velocity formula are determined according to the following formulas:

[0036]

[0037] in, P at The gas pressure inside the water storage tank. P 大气 Atmospheric pressure. λ The friction coefficient of the inner wall of the air inlet and outlet pipes of the water storage tank is given. ρ at The density of the gas inside the water storage tank. L a The length of the air inlet and outlet pipes of the water storage tank. D a The diameter of the air inlet and outlet pipes of the water storage tank is [missing information]. v at The flow velocity at the inlet end of the air inlet / outlet pipe of the water storage tank;

[0038]

[0039] in, v at and v 出口 Must satisfy no greater than , c For the speed of sound, γ The specific heat of air is the melting ratio. v 出口 The flow velocity at the outlet end of the air inlet and outlet pipe of the water storage tank;

[0040] The first set of pressure balance equations for the water storage tank without an air buffer tank includes:

[0041] τ The water volume in the storage tank at the specified time V w for:

[0042]

[0043] in, A进水 The cross-sectional area of ​​the water inlet channel;

[0044] set up for ;

[0045] τ The volume of air flowing out at any given time is:

[0046]

[0047] in, A 出气 The cross-sectional area of ​​the air inlet and outlet pipes of the water storage tank;

[0048] set up for ;

[0049] τ The air pressure inside the water storage tank at the specified time P τ for:

[0050] ;

[0051] in, V 1 represents the volume of the water storage tank;

[0052] The second set of pressure balance equations for the water storage tank when setting up the air buffer tank includes:

[0053] The volume of the air buffer tank is set to be V 2. V 1 with V 1+ V Substitution 2 yields the second set of pressure balance equations.

[0054] The variable circulation marine liquid-gas-pressure coupling energy storage device and its design method provided by this invention can produce the following beneficial effects:

[0055] 1. The variable circulation marine liquid-gas-pressure coupling energy storage device provided by this invention abandons the design approach of simply increasing the volume of the water tank to improve energy storage and conversion efficiency. By setting a group of vents on the water tank to connect with the external space, dynamic air replenishment is achieved. Specifically, during the energy storage stage, as seawater is pumped out of the water tank, a negative pressure trend is formed inside the tank. At this time, external air can be automatically replenished through the group of vents, avoiding excessive suction that would hinder the pumping process. During the power generation stage, after opening the top valve, high-pressure seawater flows in from outside, and the water flow drives the generator to rotate and generate electricity. The original gas in the water tank can be discharged through the group of vents, preventing positive pressure accumulation from causing resistance to water intake. This maintains a relatively stable internal pressure environment in the water tank during the filling and discharging process, reduces energy loss caused by pressure fluctuations, and improves energy conversion and storage efficiency.

[0056] 2. The variable circulation marine liquid-gas-pressure coupling energy storage device provided by this invention adopts a top-inlet and bottom-outlet water filling and discharging design, which changes the problem that the water flow resistance continuously increases with the rise of water level caused by the traditional bottom-filling and discharging method. During the power generation stage, high-pressure seawater enters the storage tank from top to bottom without being obstructed by the water inside the storage tank, resulting in smoother water flow and improved energy conversion and storage efficiency. Attached Figure Description

[0057] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of the structure of the variable circulation marine liquid-gas-pressure coupling energy storage device provided in an embodiment of the present invention;

[0059] Figure 2 A schematic diagram of the gas flow direction when the variable circulation marine liquid-gas-pressure coupling energy storage device provided in the embodiment of the present invention is in the energy storage stage;

[0060] Figure 3 A schematic diagram of the gas flow direction when the variable circulation marine liquid-gas-pressure coupling energy storage device provided in the embodiment of the present invention is in the power generation stage;

[0061] Figure 4 This is a top view of the variable circulation marine fluid-gas-pressure coupling energy storage device provided in an embodiment of the present invention;

[0062] Figure 5 This is a graph showing the relationship between air pressure inside the water storage tank and time, provided in an embodiment of the present invention.

[0063] Figure 6 This is a graph showing the relationship between the volumetric flow velocity at the inlet end of the air inlet pipe of the water storage tank and time, provided in an embodiment of the present invention.

[0064] Figure 7 A graph showing the relationship between the volumetric flow velocity of the water at the outlet of the water inlet channel provided in an embodiment of the present invention and time.

[0065] Figure 8 A graph showing the change in water volume in a water storage tank over time, provided in an embodiment of the present invention;

[0066] Figure 9 A comparison chart showing the relationship between gas pressure inside a water storage tank and time, provided in an embodiment of the present invention;

[0067] Figure 10 A comparison chart showing the relationship between the volumetric flow velocity at the inlet end of the air inlet pipe of the water storage tank and time, provided in an embodiment of the present invention;

[0068] Figure 11 A comparison diagram showing the relationship between the volumetric flow velocity of the water at the outlet of the water inlet channel provided in an embodiment of the present invention and the change over time;

[0069] Figure 12 A comparison chart showing the relationship between the volume of water in the storage tank and time, provided in an embodiment of the present invention.

[0070] Icons: 1-Water storage tank; 11-Outlet pipe; 12-Inlet channel; 13-Ventilation port group; 131-Buffer tank vent; 132-Atmospheric vent; 14-Counterweight; 15-Inspection door; 2-Generator set; 3-Valve; 4-Water pump; 5-Air buffer tank; 6-Connecting pipe; 7-Buffer tank inlet / outlet pipe; 8-First shielding cover; 81-Inner connection part; 82-Outer rainproof part; 9-First stay cable; 10-First float; 011-Water storage tank inlet / outlet pipe; 012-Second shielding cover; 013-Second stay cable; 014-Second float. Detailed Implementation

[0071] 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.

[0072] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0073] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0075] A first aspect of the present invention provides a variable-cycle marine liquid-gas-pressure coupled energy storage device, such as... Figure 1 and Figure 2 As shown, it includes a water storage tank 1, a generator set 2, valves 3 and a water pump 4;

[0076] The bottom of the water storage tank 1 is provided with a water outlet pipe 11, and the top of the water storage tank 1 is provided with a water inlet channel 12 and a vent assembly 13 for communicating with the external space.

[0077] Both valve 3 and generator set 2 are installed in the water inlet channel 12. Valve 3 is located above generator set 2 and is configured to control the opening and closing of the water inlet channel 12.

[0078] Water pump 4 is installed on water outlet pipe 11.

[0079] The working process of the above-mentioned variable circulation marine liquid gas-pressure coupled energy storage device is divided into two main stages: the energy storage stage and the power generation stage.

[0080] During the energy storage phase, when there is excess electrical energy in the power grid, valve 3 closes, blocking the water flow channel of inlet channel 12; simultaneously, water pump 4 is activated to forcibly discharge seawater from storage tank 1 into the external marine environment through outlet pipe 11. As seawater is continuously pumped out, the water level inside storage tank 1 decreases, the volume increases, and the internal pressure decreases. At this time, external gas is introduced into the upper space of the tank through vent group 13, so that the inside of storage tank 1 is in an air state of 1 atmosphere (1 atm) or a certain negative air pressure (below 1 atm) that storage tank 1 can withstand.

[0081] During the power generation phase, when power needs to be supplied to the grid, valve 3 opens, connecting the inlet channel 12 to the external seawater. Because the area outside the water tank 1 is under high-pressure marine conditions, seawater rapidly flows into the water tank 1 through the inlet channel 12 under the influence of external hydrostatic pressure. As the water flows through the generator set 2, it drives the turbine to rotate at high speed, generating electricity and transmitting it to the grid. As the water level in the water tank 1 rises, the internal gas phase space is compressed, and excess gas can be discharged to the outside through the vent group 13.

[0082] The variable circulation marine liquid-gas-pressure coupling energy storage device provided in the above embodiments does not rely on topographic elevation differences, but utilizes the constant high pressure of the ocean as a "natural gravity field," significantly reducing geographical site selection limitations. In addition, it breaks away from the design approach of simply increasing the volume of the water tank to improve energy storage and conversion efficiency. By setting a group of vents 13 on the water tank 1 to introduce and vent air, pressure compensation is achieved, ensuring energy conversion and storage efficiency.

[0083] In addition, the variable circulation marine liquid gas pressure coupling energy storage device provided in the above embodiment adopts a top water inlet and bottom water outlet water filling and discharging design. During the power generation stage, high pressure seawater enters the water storage tank 1 from top to bottom without being obstructed by the water inside the water storage tank 1, and the water flow is smoother, further improving the energy conversion and storage efficiency.

[0084] In summary, the variable circulation marine liquid-gas-pressure coupling energy storage device provided in the above embodiments realizes efficient storage and on-demand release of electrical energy in a marine environment. It has the advantages of reasonable structure, reliable operation, energy saving and environmental protection, and high energy conversion and storage efficiency, and has good prospects for engineering applications.

[0085] Among them, the water storage tank 1 can be constructed from high-strength and corrosion-resistant materials, such as reinforced concrete, corrosion-resistant metals, and fiber composite materials.

[0086] It should be noted that the aforementioned external space can be the space above the water surface, the space inside the underwater air buffer tank 5, or a combination of both. Of course, the external space is not limited to the examples above; any space that can be connected to the water tank 1 and can replenish gas or receive the gas discharged from the water tank 1 when the air pressure inside the water tank 1 changes is acceptable.

[0087] In alternative implementations, such as Figure 1 As shown, the vent group 13 includes a buffer tank vent 131, and the variable circulation marine liquid gas pressure coupling energy storage device also includes an air buffer tank 5, which is connected to the buffer tank vent 131 through a connecting pipe 6.

[0088] In the above embodiments, the air buffer tank 5 serves as an intermediate gas storage and regulation unit, and its volume can be smaller than that of the water tank 1. Specifically, its size and location can be determined according to the actual deployment.

[0089] During the energy storage phase, such as Figure 2 As shown, when the water level in the water storage tank 1 drops, the gas in the air buffer tank 5 can enter the water storage tank 1 through the connecting pipe 6 and the buffer tank vent 131 to replenish the increased cavity volume caused by the drainage. During the power generation phase, as... Figure 3 As shown, the water level in the water storage tank 1 rises, and the original gas in the water storage tank 1 can enter the air buffer tank 5 through the connecting pipe 6 and the vent hole 131 of the buffer tank.

[0090] Therefore, the installation of air buffer tank 5 is equivalent to increasing the gas volume of water storage tank 1. The rate of increase in gas pressure is slower compared to the case without air buffer tank 5, thus causing a lag in the magnitude of gas pressure resistance within water storage tank 1. This reduces the rate of decrease in water injection speed, thereby improving energy storage and conversion efficiency. The principle of gas pressure resistance during drainage is similar to that during water injection.

[0091] In an optional embodiment, the variable circulation marine liquid-gas-pressure coupled energy storage device may include multiple water tanks 1, each water tank 1 being independently installed in the marine environment. When an air buffer tank 5 is provided, each water tank 1 is equipped with one air buffer tank 5, or one air buffer tank 5 is provided for every few water tanks 1.

[0092] Preferably, such as Figure 4 As shown, an air buffer tank 5 is configured for every few water storage tanks 1. The air buffer tank 5 can be connected to the air vent 131 of each water storage tank 1 through several connecting pipes 6, thereby forming a unified airflow compensation network.

[0093] To facilitate rapid gas exchange between the air buffer tank 5 and the water storage tank 1, the air buffer tank 5 and the water storage tank are placed close together to reduce the length of the connecting pipe 6.

[0094] For example Figure 4 As shown, when multiple water storage tanks 1 are configured, the multiple water storage tanks 1 can be arranged around the air buffer tank 5. In particular, the multiple water storage tanks 1 can be evenly arranged around the air buffer tank 5, thereby minimizing the distance between each water storage tank 1 and the air buffer tank 5.

[0095] In alternative implementations, such as Figure 1 As shown, the top of the air buffer tank 5 is connected to the air inlet / outlet pipe 7. One end of the air inlet / outlet pipe 7 is connected to the internal space of the air buffer tank 5, and the other end is connected to the atmosphere and is provided with a first shielding cover 8.

[0096] It should be noted that the first cover 8 mentioned above mainly serves to block rain, and does not obstruct the connection between the buffer tank's inlet / outlet pipe 7 and the atmosphere.

[0097] Specifically, such as Figure 1 As shown, the first shielding cover 8 may include an inner connecting part 81 and an outer rainproof part 82. The inner connecting part 81 is directly connected to the top of the buffer tank inlet / outlet pipe 7, and its side wall is provided with a through hole, through which the buffer tank inlet / outlet pipe 7 communicates with the atmosphere. The outer rainproof part 82 covers the top of the inner connecting part 81, and its edge extends downward to shield the inner connecting part 81 from the side, preventing rainwater from entering the buffer tank inlet / outlet pipe 7 through the through hole. In addition, the outer rainproof part 82 and the through hole can also prevent larger debris from entering the buffer tank inlet / outlet pipe 7.

[0098] During the energy storage phase, such as Figure 2 As shown, the gas in the air buffer tank 5 enters the water storage tank 1 through the connecting pipe 6 and the buffer tank vent 131. Simultaneously, air on the water surface enters the air buffer tank 5 through the first shielding cover 8 and the buffer tank inlet / outlet pipe 7, replenishing the gas in the air buffer tank 5. During the power generation phase, as... Figure 3 As shown, the original gas in the water storage tank 1 enters the air buffer tank 5 through the connecting pipe 6 and the air vent 131 of the buffer tank. The gas in the air buffer tank 5 can be discharged into the atmosphere above the water surface through the air inlet and outlet pipe 7 of the buffer tank and the first shielding cover 8.

[0099] The above-described embodiment achieves communication between the external atmosphere and the internal air passage of the device by setting the buffer tank inlet and outlet air pipes 7 and the first shielding cover 8, which can further improve the energy storage and conversion efficiency.

[0100] The diameter of the connecting pipe 6 can be larger than the diameter of the air inlet / outlet pipe 7 of the buffer tank, and the length of the connecting pipe 6 is much smaller than the length of the air inlet / outlet pipe 7 of the buffer tank, so as to ensure that the gas between the water tank 1 and the air buffer tank 5 can be exchanged quickly and preferentially.

[0101] Of course, when the energy storage and conversion efficiency requirements can be met by simply setting up the air buffer tank 5, in other embodiments, the air inlet and outlet pipes 7 of the buffer tank may not be set up.

[0102] Preferably, when an air buffer tank 5 is provided, the air buffer tank 5 is also connected to a buffer tank inlet / outlet air pipe 7.

[0103] In addition, the top of the buffer tank inlet / outlet pipe 7 can be equipped with an additional filter device, such as a filter screen, to prevent large impurities from entering the buffer tank inlet / outlet pipe 7 and clogging it.

[0104] In alternative implementations, such as Figure 1 As shown, the air inlet / outlet pipe 7 of the buffer tank is provided with a plurality of first inclined cables 9 at one end near the air buffer tank 5. One end of each first inclined cable 9 is connected to the outer wall of the air inlet / outlet pipe 7 of the buffer tank or its associated fixing structure, and the other end extends and is anchored to the seabed foundation to achieve multi-directional spatial constraint on the air inlet / outlet pipe 7 of the buffer tank.

[0105] The seabed foundation can be a concrete base, steel pile structure, or gravity caisson, or other fixed facilities with sufficient load-bearing capacity, all pre-embedded in the seabed. By setting multiple radially distributed first cable-stayed cables 9, the swaying and displacement of the buffer tank's inlet and outlet pipes 7 caused by ocean current disturbances, wave impacts, or their own weight can be effectively limited under horizontal and inclined loads, thereby improving the structural stability of the entire device.

[0106] In alternative implementations, such as Figure 1As shown, the end of the air inlet / outlet pipe 7 away from the air buffer tank 5 is connected to a first float 10. The first float 10 is a sealed component with positive buoyancy, such as a closed shell made of corrosion-resistant composite material or stainless steel, whose volume and density are designed to generate upward buoyancy in seawater.

[0107] The first float 10 is configured to be suspended at a predetermined depth below the water surface, preferably below the wave-active layer, for example, between 10 and 30 meters deep, in order to avoid being directly affected by violent sea surface fluctuations.

[0108] The first float 10 is preferably shaped like a shuttle. Compared with traditional float configurations such as spherical or cylindrical shapes, the shuttle-shaped structure has an excellent streamlined shape, which can effectively divide the water flow and significantly reduce the frontal area under the action of the water flow, thereby reducing the hydrodynamic load in the horizontal direction and reducing the drag force and vibration impact on the air inlet and outlet pipes 7 of the buffer tank and the entire device.

[0109] More preferably, the first stay cable 9 and the first float 10 can be installed simultaneously to form a coordinated support system of "upward support and downward pull": the first float 10 provides upward buoyancy support, reducing the possibility of the top tilting due to the long length of the buffer tank inlet / outlet pipe 7; while multiple first stay cables 9 provide lateral restraint and anti-overturning reinforcement for the buffer tank inlet / outlet pipe 7 from below. This composite stabilizing structure not only significantly improves the operational reliability of the buffer tank inlet / outlet pipe 7 in complex marine environments, but also reduces the risk of fatigue damage caused by frequent pipe oscillation, extending the service life of the device.

[0110] The first stay cable 9 can be made of high-strength, seawater-corrosion-resistant materials, such as galvanized steel cable, fiber-reinforced polymer cable, or titanium alloy rope. It can also be equipped with an adjustable-length tensioning device to adjust the preload according to actual working conditions during installation, ensuring uniform stress distribution. The first buoy 10 can also integrate attitude sensors and communication modules for real-time monitoring of its position and, when necessary, issue maintenance warnings via a remote control system.

[0111] In alternative implementations, such as Figure 1 As shown, the vent assembly 13 includes an atmospheric vent 132. The top of the water tank 1 is connected to a water tank inlet / outlet pipe 011. One end of the water tank inlet / outlet pipe 011 is connected to the atmospheric vent 132, and the other end is connected to the atmosphere and is provided with a second shielding cover 012.

[0112] Similar to the first cover 8, the second cover 012 mainly serves to block rain, but it does not obstruct the connection between the water tank's inlet / outlet pipe 011 and the atmosphere. Its specific structure can be found in the description of the first cover 8 above, and will not be repeated here for brevity.

[0113] In the above embodiments, by setting an atmospheric vent 132 and a matching water tank inlet / outlet pipe 011 and a second shielding cover 012, the gas phase space inside the water tank 1 is directly connected to the atmosphere above the water surface.

[0114] During the energy storage phase, such as Figure 2 As shown, when the water level in water tank 1 drops, air above the water surface can enter water tank 1 through the second shield 012, the water tank inlet / outlet pipe 011, and the atmospheric vent 132, replenishing the increased cavity volume due to drainage. During the power generation phase, as... Figure 3 As shown, the water level in the water tank 1 rises, and the original gas in the water tank 1 can be discharged to the surface of the water through the atmospheric vent 132, the water tank inlet and outlet pipe 011, and the second shielding cover 012.

[0115] The above-described implementation method effectively solves the problem of pressure imbalance that may occur in energy storage devices during repeated filling and draining in marine environments by introducing a ventilation path that is directly connected to the atmosphere, thereby improving energy conversion and storage efficiency.

[0116] Based on the above implementation method, an air buffer tank 5 may or may not be provided. That is, either the air buffer tank 5 or the water tank inlet / outlet pipe 011 may be provided in the variable circulation marine liquid-gas-pressure coupling energy storage device, or both may be provided in the variable circulation marine liquid-gas-pressure coupling energy storage device.

[0117] When the air buffer tank 5 is not installed, the air inlet / outlet pipe 011 of the water storage tank needs to have a larger diameter. This is because a longer, thinner air inlet / outlet pipe 011 requires higher air pressure to discharge. When the water filling speed inside the tank exceeds the air discharge speed of the air inlet / outlet pipe 011, the air above the water storage tank 1 is gradually compressed, increasing the air pressure and affecting the seawater inflow speed. In the initial stage of water filling, the air volume inside the tank is large, and the air pressure rises slowly. In the later stages of filling, as the air volume inside the tank gradually decreases, the air pressure rises rapidly, and the water inflow resistance also increases rapidly, resulting in slower water filling and a gradual decrease in power generation efficiency. As the water flow speed gradually decreases, the air discharge speed gradually increases under the influence of air pressure. Eventually, the two reach an equilibrium point at a certain air pressure, allowing a stable water filling speed to be maintained in the later stages. Therefore, a larger diameter air inlet / outlet pipe 011 can minimize the fluctuations in air pressure inside the water storage tank 1, keeping the water filling speed consistently high.

[0118] In alternative implementations, such as Figure 1 As shown, the end of the air inlet / outlet pipe 011 of the water tank 1 is connected to a number of second stay cables 013, and the end of each second stay cable 013 away from the air inlet / outlet pipe 011 of the water tank is configured to be connected to the seabed foundation.

[0119] Similar to the first cable 9, the second cable 013 can effectively limit the swaying and displacement of the water tank inlet and outlet pipe 011 caused by ocean current disturbance, wave impact or its own weight under horizontal and inclined loads, thereby improving the structural stability of the entire device.

[0120] In alternative implementations, such as Figure 1 As shown, the end of the air inlet / outlet pipe 011 of the water tank away from the water tank 1 is connected to a second float 014, which is configured to be located below the water surface.

[0121] Similar in function and shape to the first float 10, the second float 014 can provide upward buoyancy support for the air inlet / outlet pipe 011 of the water tank, reducing the possibility of the top tilting due to the long length of the air inlet / outlet pipe 011 of the water tank.

[0122] Preferably, the second stay cable 013 and the second float 014 are provided simultaneously.

[0123] In alternative implementations, such as Figure 1 As shown, when the seawater inside the water storage tank 1 is emptied, if the anti-buoyancy requirements are not met, a counterweight 14 is provided at the bottom of the water storage tank 1.

[0124] The counterweight 14 can be made of reinforced concrete blocks, lead blocks, etc., and the counterweight 14 can be set inside the water storage tank 1 or outside the water storage tank 1.

[0125] In alternative implementations, such as Figure 1 As shown, the water storage tank 1 is equipped with an inspection door 15, which can serve as a passage for construction personnel or maintenance personnel to enter and exit the tank.

[0126] Of course, when the variable circulation marine liquid gas-pressure coupling energy storage device is equipped with an air buffer tank 5, the air buffer tank 5 can also be equipped with a counterweight 14 and an inspection door 15.

[0127] The following details the construction steps of the aforementioned variable-circulation marine liquid-gas-pressure coupled energy storage device:

[0128] 1. Both the water storage tank 1 and the air buffer tank 5 are prefabricated concrete spherical shell units. The thickness of the spherical shell unit is the same as that of the water storage tank 1 and the air buffer tank 5. The prefabricated spherical shell units are transported to the construction site.

[0129] 2. On-site, the spherical shell units are connected by rigid nodes. The spherical shell units on the same horizontal ring are assembled simultaneously, while the spherical shell units at different elevations are assembled from bottom to top. Horizontal and vertical joints are left between each spherical shell unit, and concrete or grout is poured into the joints afterward.

[0130] 3. After the spherical shell units are assembled into a complete sphere, they are positioned in the deep ocean. During the sinking of water tank 1, the weight of water tank 1 and the buoyancy force are controlled by opening and closing the inspection door 15 and the valve 3 on the top of water tank 1, so as to facilitate the sinking construction. Before sinking, water tank 1 is equipped with a counterweight 14, which can be installed by pouring concrete or by placing a high-density material block at the bottom of the tank. During the sinking of air buffer tank 5, the weight of air buffer tank 5 and the buoyancy force are controlled by opening and closing the inspection door 15.

[0131] 4. After each water tank 1 and air buffer tank 5 is in place, install the connecting pipe 6, the air inlet / outlet pipe 7 of the buffer tank, the air inlet / outlet pipe 011 of the water tank, the first float 10, and the second float 014, etc. When the air buffer tank 5 is not installed, each water tank 1 is equipped with a separate air inlet / outlet pipe 011; when the air buffer tank 5 is installed, the air inlet / outlet pipe 7 of the buffer tank is installed on the top of the air buffer tank 5, and whether the air inlet / outlet pipe 011 of the water tank is installed is determined as needed.

[0132] 5. At least three first inclined cables 9 are installed in the lower middle part of the air inlet and outlet pipe 7 of the buffer tank, and at least three second inclined cables 013 are installed in the lower middle part of the air inlet and outlet pipe 011 of the water storage tank.

[0133] 6. Install generator set 2, valve 3 and water pump 4, install inspection door 15 and other circuit equipment and electrical components;

[0134] 7. Connect generator set 2 to the power grid and water pump 4 to the power source.

[0135] A second aspect of the present invention provides a design method for a variable-circulation marine fluid-gas-pressure coupled energy storage device. The design method provided in this second aspect is used to design the aforementioned variable-circulation marine fluid-gas-pressure coupled energy storage device, comprising:

[0136] Formula for the water flow velocity at the outlet of the water inlet channel 12 in the water storage tank 1 when the air buffer tank 5 is not installed;

[0137] When it is determined that the air buffer tank 5 is not installed and the air inlet and outlet pipe 011 of the water tank is vented, the formulas for the inlet velocity and the outlet velocity of the air inlet and outlet pipe 011 of the water tank are as follows:

[0138] Based on the water flow velocity formula and the inlet velocity formula, the first set of air pressure balance equations for water storage tank 1 when air buffer tank 5 is not installed is established.

[0139] The second set of pressure balance equations for water tank 1 when air buffer tank 5 is set is obtained based on the first set of pressure balance equations.

[0140] The design method provided in the above embodiments makes it easier for designers to find the geometric dimensions of each component that meet the predetermined target requirements for energy conversion efficiency.

[0141] Since the size of the water storage tank 1 and the air buffer tank 5, the diameter of the water inlet channel 12, the length and diameter of the water storage tank inlet and outlet air pipes 011 and 7 of the buffer tank have a significant impact on the power generation efficiency, the following will establish the gas pressure-time relationship function, exhaust velocity-time relationship function, water flow velocity-time relationship function and water inlet volume-time relationship function in the water storage tank 1 and the air buffer tank 5 based on fluid mechanics and aerodynamics theory, and thus form the design method of variable circulation marine liquid gas pressure coupling energy storage device with and without air buffer tank 5.

[0142] 1. Calculation of the water flow velocity at the outlet of the water inlet channel 12 in water storage tank 1 when air buffer tank 5 is not installed and air is vented through the air inlet / outlet pipe 011 of the water storage tank:

[0143] Water flows from top to bottom into the water storage tank 1 through the inlet of the inlet channel 12. The length of the inlet channel 12 is generally short, and the fluid velocity-pressure formula for a pipe with no elevation difference at the inlet and outlet is approximately used:

[0144] (1)

[0145] in, P w The liquid pressure at the inlet of the water inlet channel 12. P at The gas pressure inside water storage tank 1 λ The coefficient of friction of the inner wall of the water inlet channel 12. ρ w For water density, L w The length of the water inlet channel 12 d w The diameter of the water inlet channel 12 is... v wt The water flow velocity at the outlet of the inlet channel 12.

[0146] The water flow velocity at the outlet of the inlet channel 12 can be obtained from equation (1):

[0147] (2)

[0148] II. Calculation of flow velocities at the inlet and outlet ends of the air inlet / outlet pipe 011 of the water storage tank when the air buffer tank 5 is not installed and the water storage tank inlet / outlet pipe 011 is vented:

[0149] Euler's differential equation for one-dimensional flow of gas in a pipeline, considering frictional losses along the pipeline:

[0150] (3)

[0151] From equation (3), we can deduce:

[0152] (4)

[0153] in, P at The gas pressure inside water storage tank 1 P 大气 Atmospheric pressure (1 atm = 101325 Pa). λ Let be the coefficient of friction of the inner wall of the air inlet / outlet pipe 011 of the water storage tank. ρ at The density of the gas inside water storage tank 1. L a The length of the air inlet / outlet pipe 011 of the water storage tank. D a The diameter of the air inlet / outlet pipe 011 of the water storage tank. v at The flow velocity at the inlet end of the air inlet / outlet pipe 011 of the water storage tank.

[0154] From equation (4), we get:

[0155] (5)

[0156] From the fluid continuity equation:

[0157] (6)

[0158] in, ρ 空气 air density, v 出口 The flow velocity at the outlet end of the air inlet / outlet pipe 011 of the water storage tank.

[0159] If the air inlet and outlet pipe 011 of the seawater storage tank is considered as a constant temperature pipeline, then:

[0160] (7)

[0161] From equations (6) and (7), we can obtain:

[0162] (8)

[0163] in, v at and v 出口 Must satisfy no greater than c is the speed of sound. γ This is the specific heat of air melt ratio.

[0164] III. Establishing the first set of air pressure balance equations for water storage tank 1 when air buffer tank 5 is not installed:

[0165] (i) τ The water volume in water storage tank 1 at any given time is:

[0166] (9)

[0167] in, A 进水 Let be the cross-sectional area of ​​the water inlet channel 12.

[0168] Substituting equation (2) into equation (9), we get:

[0169] (10)

[0170] set up for .

[0171] (ii) τ The volume of air flowing out at any given time (relative to the initial air pressure) is:

[0172] (11)

[0173] in, A 出气 The cross-sectional area of ​​the air inlet / outlet pipe 011 of the water storage tank.

[0174] Gas density in water storage tank 1 over time t The function of change is:

[0175] (12)

[0176] Substituting equations (5) and (12) into equation (11), we get:

[0177] (13)

[0178] set up for .

[0179] τ The air pressure inside the water storage tank 1 P τ for:

[0180] (14)

[0181] in, V 1 represents the volume of water storage tank 1.

[0182] τ Taking the differential , Then equation (14) is:

[0183] (15)

[0184] time t =0 corresponds to the initial atmospheric pressure P 1 = 1 atm.

[0185] From equation (15), we can obtain:

[0186] (16)

[0187] (17)

[0188] ...

[0189] (18)

[0190] The curves of air pressure change over time inside water storage tank 1 can be obtained from equations (16) to (18). P at quantile values P i Thus we obtain P at The function curve; P at Substituting into equation (2) yields v wt The function curve; P at Substituting into equation (5) yields v at The function curve; P at Substituting into equation (10) yields V w The function curve.

[0191] Set the air buffer tank volume to V 2. The formulas (14) to (18) are... V 1 with V 1+ V 2. Substitution yields the functional relationships when the air buffer tank 5 is set.

[0192] The following specific examples illustrate the effects of having and not having an air buffer tank 5 on the gas pressure inside the water tank 1, the water flow velocity at the outlet, and the exhaust velocity of the water tank 1, as well as the relationships between the variables.

[0193] Calculation Example 1:

[0194] The water storage tank 1 and the air buffer tank 5 have an inner diameter of 20m. The top of the water storage tank 1 is 50m above the sea surface and has an inner diameter of 0.7m. The connecting pipe 6 between the water storage tank 1 and the air buffer tank 5 is 10m long and has an inner diameter of 1m. The water inlet channel 12 of the water storage tank 1 has an inner diameter of 2m and a length of 2m.

[0195] Set water density The roughness of the inner wall of the smooth concrete pipe and the inner wall of the ordinary steel pipe is 0.045 mm. Under turbulent water flow conditions, the friction coefficient is... λ ≈0.013, air specific heat ratio γ =1.4, constant R=287 J / kg.K, T=293 K at 20℃, 1atm=101325 Pa.

[0196] From the given conditions, we can conclude that:

[0197]

[0198] again:

[0199]

[0200]

[0201] but:

[0202]

[0203]

[0204] The curves of each function relationship obtained from equations (14) to (18) are as follows: Figures 5 to 8 As shown.

[0205] Depend on Figure 6 It is known that the airflow velocity (the vertical axis in the diagram represents the volumetric velocity, which needs to be divided by the cross-sectional area of ​​the pipe) never exceeds the speed of sound throughout the entire process. There was no blockage in the airflow duct.

[0206] Depend on Figures 5 to 7 It can be seen that when water is first added to storage tank 1, its air pressure is 1 atm. At this time, the flow velocity (volume velocity) of the water under the pressure difference between the inside and outside of the tank is the largest, which is 98.6 m / s. 3 The initial air velocity is 0 m / s, but since the pressure difference between the inside and outside of the tank is zero at the start of water filling, the initial air velocity is also zero. Therefore, as the volume of liquid inside the tank increases, the air pressure and density gradually increase, the pressure difference between the inside and outside of the tank gradually increases, the outflow velocity of the air gradually increases, and the inflow velocity of the liquid gradually decreases. In this example, the tank is full of water in 45.5 seconds. At this point, the volumetric velocity of the liquid has increased from the initial 98.6 m / s. 3 / s decreased to 51.8 m 3 / s, the air volumetric velocity gradually increases from the initial 0 to a maximum value of 64.1 m / s. 3 / s later, at the end of the water injection period of 45.5 seconds, it dropped to 57.8 m. 3 / s. Average velocity of water flow throughout the entire injection process. The decrease in water injection speed is due to the increased air pressure resisting the water inflow. (Definition) The water injection efficiency coefficient, or simply water injection efficiency coefficient, is the factor that controls the impact of air pressure. This is one of the important design parameters of this energy storage device. The water injection efficiency coefficient in this example has been calculated. .

[0207] To investigate the effects of different inlet and outlet air pipe diameters (011) on the air pressure and water injection rate inside water tank 1, this embodiment uses the calculation method given above to calculate and compare the function curves for different diameters (0.7 m, 0.4 m, 0.1 m) of the air pipes (011) with and without an air buffer tank 5 (20 m in diameter), as shown in the graph. Figures 9 to 12 As shown.

[0208] Depend on Figures 9 to 12 As shown, with all other conditions remaining unchanged, only the diameter of the air inlet and outlet pipes is changed, the water injection efficiency coefficient for different pipe diameters is... The values ​​are shown in Table 1.

[0209] Table 1 Value Comparison Analysis Table:

[0210]

[0211] Table 1 leads to the following conclusions: Without air buffer tank 5, the diameter of the water tank inlet / outlet pipe 011 decreases, causing a rapid drop in the water injection efficiency coefficient and consequently a decrease in energy conversion efficiency. With air buffer tank 5, the decrease in water injection efficiency coefficient is not significant. Therefore, without air buffer tank 5, the water tank inlet / outlet pipe 011 must have a sufficiently large diameter to obtain a sufficiently high water injection efficiency coefficient. It is evident that installing air buffer tank 5 significantly improves energy storage and release efficiency. In the specific design, by adjusting parameters such as the matching inlet diameter, the diameter of the water tank inlet / outlet pipe 011, the volume of water tank 1, and the volume of air buffer tank 5, and repeatedly iterating using the above calculation method, the energy conversion efficiency (positive phase water injection efficiency coefficient) that meets the predetermined target requirements can be found. The geometric dimensions of each component.

[0212] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable-circulation marine liquid-gas-pressure coupled energy storage device, characterized in that, Includes a water storage tank (1), a generator set (2), valves (3) and a water pump (4); The bottom of the water storage tank (1) is provided with a water outlet pipe (11), and the top of the water storage tank (1) is provided with a water inlet channel (12) and a vent assembly (13) for communicating with the external space. The valve (3) and the generator set (2) are both installed in the water inlet channel (12). The valve (3) is located above the generator set (2) and is configured to control the opening and closing of the water inlet channel (12). The water pump (4) is installed at the inlet of the water outlet pipe (11); The ventilation port group (13) includes an atmospheric ventilation port (132). The top of the water storage tank (1) is connected to a water storage tank inlet / outlet pipe (011). One end of the water storage tank inlet / outlet pipe (011) is connected to the atmospheric ventilation port (132), and the other end is connected to the atmosphere. The ventilation port group (13) includes a buffer tank ventilation hole (131), and the variable circulation marine liquid gas pressure coupling energy storage device also includes an air buffer tank (5). The air buffer tank (5) is connected to the buffer tank ventilation hole (131) through a connecting pipe (6). The inner diameter of the water storage tank inlet and outlet pipe (011) is smaller than the inner diameter of the connecting pipe (6). The top of the air buffer tank (5) is connected to a buffer tank inlet / outlet pipe (7). One end of the buffer tank inlet / outlet pipe (7) is connected to the space inside the air buffer tank (5), and the other end is connected to the atmosphere.

2. The variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 1, characterized in that, The water storage tank (1) is configured in multiple ways, and the air vent (131) of each water storage tank (1) is connected to the air buffer tank (5) through the connecting pipe (6).

3. The variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 1, characterized in that, The end of the air inlet / outlet pipe (011) of the water storage tank that is connected to the atmosphere is provided with a second cover (012).

4. The variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 1, characterized in that, The buffer tank inlet / outlet pipe (7) is provided with a first shielding cover (8) at the end that is connected to the atmosphere.

5. The variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 4, characterized in that, The air inlet / outlet pipe (7) of the buffer tank is connected to a plurality of first inclined cables (9) at one end near the air buffer tank (5), and the end of each first inclined cable (9) away from the air inlet / outlet pipe (7) of the buffer tank is configured to be connected to the seabed foundation. And / or, the end of the air inlet / outlet pipe (7) of the buffer tank away from the air buffer tank (5) is connected to a first float (10), the first float (10) being configured to be below the water surface.

6. The variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 1, characterized in that, The end of the air inlet / outlet pipe (011) of the water tank near the water tank (1) is connected to a plurality of second stay cables (013), and the end of each second stay cable (013) away from the air inlet / outlet pipe (011) of the water tank is configured to be connected to the seabed foundation; And / or, the end of the air inlet / outlet pipe (011) of the water tank away from the water tank (1) is connected to a second float (014), the second float (014) being configured to be below the water surface.

7. The variable circulation marine fluid-gas-pressure coupled energy storage device according to any one of claims 1-6, characterized in that, The bottom of the water storage tank (1) is provided with a counterweight (14), and / or the water storage tank (1) is provided with an inspection door (15).

8. A design method for a variable-circulation marine liquid-gas-pressure coupled energy storage device, characterized in that, For designing a variable-cycle marine fluid-gas-pressure coupled energy storage device as described in any one of claims 1-7, comprising: Formula for the water flow velocity at the outlet of the water inlet channel (12) in the water storage tank (1) when no air buffer tank (5) is set; When it is determined that no air buffer tank (5) is set and the water tank inlet and outlet air pipe (011) is vented, the inlet velocity formula and outlet velocity formula of the water tank inlet and outlet air pipe (011) are as follows: Based on the water flow velocity formula and the inlet flow velocity formula, establish the first set of air pressure balance equations for the water storage tank (1) when no air buffer tank (5) is installed; The second set of pressure balance equations for the water storage tank (1) when the air buffer tank (5) is set is obtained based on the first set of pressure balance equations.

9. The design method of the variable circulation marine liquid-gas-pressure coupled energy storage device according to claim 8, characterized in that, include: The formula for determining the water flow velocity is as follows: in, P w The liquid pressure at the inlet of the water inlet channel (12) is the pressure of the liquid. P at The gas pressure inside the water storage tank (1) is λ The coefficient of friction of the inner wall of the water inlet channel (12) is given by the given information. ρ w For water density, L w The length of the water inlet channel (12) is... d w The diameter of the water inlet channel (12) is... v wt The water flow velocity at the outlet; The inlet velocity formula and the outlet velocity formula are determined according to the following formulas: in, P at The gas pressure inside the water storage tank (1) is P 大气 Atmospheric pressure. λ The coefficient of friction of the inner wall of the air inlet / outlet pipe (011) of the water storage tank. ρ at The density of the gas inside the water storage tank (1) is given. L a The length of the air inlet / outlet pipe (011) of the water storage tank. D a The diameter of the air inlet / outlet pipe (011) of the water storage tank. v at The flow velocity at the inlet end of the air inlet / outlet pipe (011) of the water storage tank; in, v at and v 出口 Must satisfy no greater than , c For the speed of sound, γ The specific heat of air is the melting ratio. v 出口 The flow velocity at the outlet end of the air inlet / outlet pipe (011) of the water storage tank; The first set of pressure balance equations for the water storage tank (1) without the air buffer tank (5) includes: τ The water volume in the storage tank (1) at the specified time V w for: in, A 进水 The cross-sectional area of ​​the water inlet channel (12); set up for ; τ The volume of air flowing out at any given time is: in, A 出气 The cross-sectional area of ​​the air inlet / outlet pipe (011) of the water storage tank; set up for ; τ The air pressure inside the water storage tank (1) at the specified time P τ for: ； in, V 1 represents the volume of the water storage tank (1); The second set of pressure balance equations for the water storage tank (1) when setting up the air buffer tank (5) includes: The volume of the air buffer tank (5) is set as follows: V 2. V 1 with V 1+ V Substitution 2 yields the second set of pressure balance equations.

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