A method, system and application of self-adaptive jet drag reduction with speed

Abstract

The application relates to a kind of self-adaptive injection drag reduction method, system and application of speed, belong to underwater drag reduction technical field;The specific steps of drag reduction method are as follows: arranging data acquisition module on the vehicle;Real-time sailing speed of the vehicle and the flow value of polymer injection are obtained by the data acquisition module;The information obtained by the data acquisition module is accepted and analyzed by the control module, the mapping relationship between sailing speed and injection rate is compared, the corresponding injection rate calculation value of the measured sailing speed is obtained, and then the control instruction is output to the driving module, the actual value of the polymer injection rate is adjusted until it is equal to the calculation;The polymer solution in the liquid storage module is sucked to the polymer injection outlet by the driving module, and passes through the pressure stabilizing module;The pressure fluctuation in the polymer injection state is absorbed by the pressure stabilizing module.The application solves the shortcomings of the prior art, such as underwater vehicle injection pressure fluctuation and low polymer injection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of underwater drag reduction technology, specifically relating to an adaptive jet drag reduction method, system, and application based on speed. Background Technology

[0002] During underwater vehicle navigation, the main source of drag is surface friction, with viscous friction, caused by friction between solid and liquid surfaces, accounting for up to 80% of the total friction drag. Therefore, reducing friction drag is a key direction in drag reduction technology research for underwater vehicles. Polymer additive drag reduction is a highly efficient method. This technology only requires adding a trace amount of drag-reducing agent to the turbulent flow field to alter the turbulent flow structure, achieving a significant drag reduction effect. It is also easy to apply and has already been demonstrated in applications such as oil pipeline transportation and district heating. To achieve external drag reduction in underwater vehicles, polymers are typically sprayed onto the outer surface of the vehicle. Compared to polymer solutions of the same concentration, spraying exhibits superior drag reduction performance. Therefore, polymer solution spraying is a potential drag reduction and energy-saving method for underwater vehicles, and it holds promise for achieving long-term, high-efficiency drag reduction.

[0003] Existing technology discloses a drag reduction device for underwater vehicles, which uses a gas cylinder to provide the driving force for the release of viscous fluid, thereby moving a piston cylinder to release drag-reducing viscous fluid from inside a pipe onto most of the outer surface of the underwater vehicle. This increases the maximum speed of the underwater vehicle and reduces energy consumption at the same speed. However, because the gas cylinder occupies space from other components, and the pressure inside the cylinder gradually decreases as gas is released, there is a possibility of insufficient pressure supply to the drag-reducing viscous fluid, preventing its smooth ejection. Existing technology also discloses a drag reduction method using artificial ventilation. To advance the integrated configuration, a torpedo structure was designed to avoid instability in motion caused by simultaneous thrust from both the front and rear, while providing uniform thrust. This integrated the torpedo propulsion system and drag reduction system into one. However, this torpedo drag reduction structure requires manual ventilation, making operation complex and difficult to implement.

[0004] Currently, polymer injection is typically achieved through steady-state injection, meaning the injection rate and flow rate remain constant regardless of the underwater vehicle's operating conditions. A drawback of this approach is that the polymer cannot be maximized under limited conditions. Therefore, it is urgent to find ways to fully utilize polymer injection efficiency and improve its stability to enhance the speed and long-range capabilities of underwater vehicles. Summary of the Invention

[0005] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides an adaptive jetting drag reduction method and system that adjusts the jetting rate according to the underwater vehicle's speed. This allows the jetting rate of the polymer to vary with the underwater vehicle's speed, achieving optimal drag reduction while improving jetting efficiency and reducing pressure fluctuations during polymer jetting, thereby enhancing the underwater vehicle's speed and long-range performance. This invention overcomes the drawbacks of existing technologies, such as pressure fluctuations during underwater vehicle jetting and low polymer jetting efficiency.

[0006] The technical solution of this invention is: an adaptive jet drag reduction method based on speed, the specific steps of which are as follows: Install data acquisition modules on the aircraft; The real-time speed of the vehicle and the flow rate of the polymer jet are obtained by the data acquisition module; The control module receives and analyzes the information acquired by the data acquisition module, compares it with the mapping relationship between speed and jet rate, obtains the calculated value of the jet rate corresponding to the measured speed, and then outputs control commands to the drive module to adjust the actual value of the polymer jet rate until it is equal to the calculated value. The polymer solution in the storage module is drawn by the drive module and ejected from the polymer spray outlet, passing through the pressure stabilizing module; the pressure stabilizing module absorbs the pressure fluctuations during polymer spraying.

[0007] A further technical solution of the present invention is: the pressure stabilizing module includes a pressure stabilizing chamber, a return pipeline connecting the pressure stabilizing chamber and the liquid storage module, a pressure sensor for measuring pressure pulsation signals in the return pipeline, and a pressure stabilizing chamber valve for controlling the on / off state and flow rate of the pressure stabilizing chamber; The pressure stabilizing chamber is connected to the injection pipeline between the drive module and the polymer solution injection outlet. By utilizing the compressibility of the air inside the chamber, it absorbs pulsating pressure to stabilize the injection pressure of the polymer solution.

[0008] An implementation system for an adaptive jet drag reduction method based on speed includes a control module, a data acquisition module, a drive module, a pressure stabilization module connected thereto, a liquid storage module for storing polymer solution, and a jet pipeline; The liquid storage module maintains the buoyancy of the vehicle by communicating with seawater; The data acquisition module is installed on the vehicle and is used to collect the vehicle's real-time speed and the flow rate of the polymer jet. The control module receives and analyzes the information acquired by the data acquisition module and outputs control commands to the drive module; The drive module adjusts the flow rate according to the command, drawing the polymer solution in the liquid storage module into the spray pipeline, and then spraying it out from the spray outlet; a spray outlet valve is provided at the spray outlet to control the on / off state and the flow rate. The pressure stabilizing module is connected to the injection pipeline and is used to absorb pressure fluctuations when the polymer solution is ejected.

[0009] A further technical solution of the present invention is: the liquid storage module includes a liquid storage chamber, a polymer inlet valve for controlling the opening and closing of the polymer inlet, and a seawater inlet connected to seawater; the liquid storage chamber is provided with a polymer inlet, a pipe connected to the seawater inlet, and an outlet connected to the drive module.

[0010] A further technical solution of the present invention is as follows: the drive module includes a motor, a plunger pump, and a plunger pump inlet valve. The motor is connected to the plunger pump main shaft via a coupling. The plunger pump inlet is connected to the outlet of the liquid storage chamber, and a plunger pump inlet valve is provided on the connecting pipeline. The plunger pump outlet is connected to the inlet of the injection pipeline.

[0011] A further technical solution of the present invention is as follows: the pressure stabilizing module includes a pressure stabilizing chamber, the input port of the pressure stabilizing chamber is connected to the injection pipeline, and the output port is connected to the liquid storage chamber through the return pipeline. Both the input port and the output port are located below the liquid surface of the polymer solution in the chamber, and the liquid surface is occupied by gas. The return pipeline is equipped with a pressure stabilizing chamber valve and a pressure sensor, which are used to control the opening and closing of the return pipeline and to measure the pressure pulsation signal of the return pipeline and feed it back to the control module.

[0012] A further technical solution of the present invention is as follows: the pressure stabilizing module includes a pressure stabilizing chamber, which is connected in series on the injection pipeline and communicates with the liquid storage chamber through the return pipeline. The two ports of the injection pipeline connected in series and the port communicating with the return pipeline are all located below the liquid surface of the polymer solution in the chamber, and the liquid surface is occupied by gas. The return pipeline is provided with a pressure stabilizing chamber valve and a pressure sensor for controlling the opening and closing of the return pipeline and for measuring the pressure pulsation signal of the return pipeline and feeding it back to the control module.

[0013] A further technical solution of the present invention is: the data acquisition module includes a speed sensor for measuring the sailing speed and a flow meter for measuring the flow rate in the jet pipe; the speed sensor is installed on the aircraft and the flow meter is installed on the jet pipe.

[0014] A further technical solution of the present invention is that the control module is a programmable controller, which stores data on the mapping relationship between different speeds and the optimal jet rate.

[0015] The application of an implementation system for an adaptive jet drag reduction method based on speed on an aircraft, wherein the implementation system is installed on the aircraft; The programmable controller controls the pressure regulating chamber valve, the jet outlet valve, and the plunger pump inlet valve to close, while the polymer inlet valve opens; then, an external pump injects polymer solution into the storage chamber, at which point the seawater inlet is in a draining state. After the polymer solution is filled, the programmable controller controls the polymer inlet valve to close, while simultaneously opening the jet outlet valve and the plunger pump inlet valve, and starts the motor. The motor speed is controlled by the programmable controller. The polymer solution passes through the flow meter, the pressure stabilizing chamber and the jet outlet valve in sequence and is then ejected from the jet outlet. The programmable controller receives the sailing speed signal from the speed sensor and obtains the corresponding jet rate Q based on the optimal mapping relationship between sailing speed and jet rate. i The formula for calculating the motor speed n is as follows: n=L Q i / v Where L is the spanwise length of the surface of the underwater vehicle to be drag-reduced, and v is the displacement of the plunger pump. If the flow rate value fed back to the programmable controller by the flow meter deviates from the calculated value, the programmable controller will fine-tune the motor until the actual spray rate of the nozzle is equal to the calculated value, and then stop issuing control execution commands. The pressure stabilizing chamber stabilizes the pressure of the ejected polymer solution. The programmable controller monitors the pressure pulsation signal obtained by the pressure sensor in real time and adjusts the pressure stabilizing chamber valve in real time to return the pulsating flow in the return pipeline to the storage chamber. At the same time, the compressed gas in the pressure stabilizing chamber absorbs the pulsating pressure and reduces the interference caused by the vibration of the motor and valve or the moment of start-stop when they change their state. After completing the adaptive jet drag reduction based on speed, the programmable controller controls the closure of the pressure stabilizing chamber valve, the jet outlet valve, and the plunger pump inlet valve to prevent leakage of the polymer solution in the storage chamber.

[0016] Beneficial effects The beneficial effects of this invention are as follows: This invention proposes a speed-adaptive jetting drag reduction system, including a speed sensor, a plunger pump inlet, a valve, a pressure sensor, a pressure stabilizing chamber, a jet outlet, a programmable controller, a motor, a plunger pump, a polymer inlet, a seawater inlet, a storage chamber, and a flow meter. The drag reduction method using this system achieves optimal polymer jetting when the underwater vehicle's speed changes, and reduces pressure fluctuations during polymer jetting, thereby reducing interference with the underwater vehicle's navigation state and achieving the optimal drag reduction effect of jetting rate adapting to speed. Specific advantages are as follows: 1. The mapping relationship between sailing speed and optimal jet rate, pre-stored within the programmable controller, is used as... The method of adjusting the motor speed connected to the plunger pump can quickly determine the optimal matching relationship between sailing speed and jet rate; 2. Connect the liquid storage chamber to the outside seawater to ensure that the total amount of polymer ejected is equal to the amount of seawater entering, so as not to change the buoyancy of the underwater vehicle while ejecting polymer.

[0017] 3. The pressure stabilizing chamber is connected between the flow meter and the polymer injection outlet to ensure constant pressure and stable flow rate of the injected polymer solution. A pressure sensor and a pressure stabilizing chamber valve are installed on the return pipe of the pressure stabilizing chamber. The programmable controller monitors the pressure pulsation signal obtained by the pressure sensor in real time and makes real-time adjustments to the pressure stabilizing chamber valve to return the pulsating flow in the pipeline to the storage chamber. In addition, a portion of air is reserved in the pressure stabilizing chamber. When the air in the chamber is compressed, it can absorb the interference caused by the vibration of the motor and valve when changing their own state or the moment of start-up and shutdown, and reduce the pressure fluctuation during polymer injection, thereby reducing the interference of polymer injection on the navigation status of the underwater vehicle. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an adaptive jet drag reduction system based on speed according to Embodiment 1 of the present invention.

[0019] Figure 2 This is a schematic diagram of an adaptive jet drag reduction system based on speed in Embodiment 2 of the present invention.

[0020] Figure 3 This refers to the matching relationship between sailing speed and jet rate.

[0021] Figure 4 The drag reduction rate is given at different sailing speeds.

[0022] Explanation of reference numerals in the attached diagram: 1. Speed ​​sensor; 2. Plunger pump inlet; 3. Pressure regulating chamber valve; 4. Pressure sensor; 5. Pressure regulating chamber; 6. Injection outlet valve; 7. Injection outlet; 8. Programmable controller; 9. Motor; 10. Plunger pump; 11. Plunger pump inlet valve; 12. Polymer inlet valve; 13. Polymer inlet; 14. Seawater inlet; 15. Storage chamber; 16. Flow meter. Black parallel lines represent pipes, and thin solid lines represent signal transmission between the controller and the controlled components. Detailed Implementation

[0023] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0024] Based on the shortcomings of existing technologies, such as pressure fluctuations in underwater vehicle jetting and low polymer jetting efficiency, this invention proposes a speed-adaptive jetting drag reduction method and system. This method achieves optimal polymer jetting when the underwater vehicle's speed changes, and reduces pressure fluctuations during polymer jetting, thereby reducing interference with the underwater vehicle's navigation status and achieving the optimal drag reduction effect of jetting rate adapting to speed.

[0025] This embodiment of an adaptive jet drag reduction system based on speed mainly consists of a speed sensor 1, a plunger pump inlet 2, a pressure regulating chamber valve 3, a pressure sensor 4, a pressure regulating chamber 5, a jet outlet valve 6, a jet outlet 7, a programmable controller 8, a motor 9, a plunger pump 10, a plunger pump inlet valve 11, a polymer inlet valve 12, a polymer inlet 13, a seawater inlet 14, a liquid storage chamber 15, and a flow meter 16.

[0026] The programmable controller 8 receives signals from the speed sensor 1, pressure sensor 4, and flow meter 16, and sends commands to the motor 9 and various valves to match the jet speed at the injection outlet 7 with the navigation speed, achieving efficient drag reduction. The programmable controller internally stores a mapping relationship between navigation speed and the optimal jet rate, which serves as the basis for adjusting the motor speed connected to the plunger pump. This relationship can be obtained through empirical data from model tests, or by fixing the underwater vehicle at a certain navigation speed and adjusting the jet rate to ultimately find the optimal match between navigation speed and jet rate.

[0027] To maintain the underwater vehicle's buoyancy while spraying polymer, the outlet at the other end of the storage chamber is connected to external seawater, ensuring that the total amount of polymer sprayed is equal to the amount of seawater entering. A pressure stabilizing chamber is connected between the flow meter and the polymer spray outlet, ensuring constant pressure and stable flow of the sprayed polymer solution. A pressure sensor and a pressure stabilizing valve are installed on the return pipe of the pressure stabilizing chamber. The programmable controller monitors the pressure pulsation signal obtained by the pressure sensor in real time and adjusts the pressure stabilizing valve accordingly, returning the pulsating flow in the pipeline to the storage chamber. Additionally, a portion of air is reserved in the pressure stabilizing chamber. When the air in the chamber is compressed, it absorbs interference caused by the vibration of the motor and valves during changes in their state or momentary start-stop operations, reducing pressure fluctuations during polymer spraying and thus minimizing interference with the underwater vehicle's navigation.

[0028] Reference Figure 3 As shown, the matching relationship between sailing speed and jet rate was obtained through a towed water tank experiment, which served as the basis for the adjustment of the programmable controller 8.

[0029] First, a polymer solution of a certain concentration needs to be prepared. The concentration calculation formula is as follows:

[0030] In the formula, Concentration, unit is ppm; W PEO W represents the mass of the solute PEO polymer, expressed in grams. 水 This represents the mass of the solvent, expressed in grams.

[0031] The drag reduction rate is calculated using the following formula:

[0032] In the formula, DR is the drag reduction ratio; ΔP 水 ΔP represents the pressure drop under spray conditions, measured in Pa. PEO The pressure drop is measured in Pa under PEO solution spraying conditions.

[0033] The spray rate of the polymer solution was normalized using Q. i / Q s It means that Q i Q is the injection rate. s The volumetric flow rate per unit span of the viscous sublayer is 67.3υ, where υ is the kinematic viscosity of water.

[0034] Example 1: In this embodiment, the PEO solution concentration was 100 ppm and the molecular weight was 8 million. Although polyethylene oxide (PEO) has the disadvantage of being easily degraded, it has a good drag reduction effect, and when spray drag reduction is used, only one shearing action occurs, which has little impact on the drag reduction effect. Therefore, PEO was used as the drag reduction agent in this experiment.

[0035] The liquid storage module consists of a liquid storage chamber 15, a polymer inlet valve 12 for controlling the opening and closing of the polymer inlet, and a seawater inlet 14 connected to seawater. The liquid storage chamber is provided with a polymer inlet 13, a pipe connected to the seawater inlet, and an outlet connected to the drive module.

[0036] The drive module consists of a motor 9, a plunger pump 10, and a plunger pump inlet valve 11. The motor 9 and the main shaft of the plunger pump 10 are connected by a coupling. The plunger pump inlet 2 is connected to the outlet of the liquid storage chamber 15, and the plunger pump inlet valve 11 is provided on the connecting pipeline. The outlet of the plunger pump 10 is connected to the inlet of the injection pipeline.

[0037] A pressure stabilizing module is composed of a pressure stabilizing valve 3, a pressure sensor 4, and a pressure stabilizing chamber 5. The input port of the pressure stabilizing chamber 3 is connected to the injection pipeline, and the output port is connected to the liquid storage chamber 15 through the return pipeline. Both the input and output ports are located below the liquid surface of the polymer solution in the chamber, while the liquid surface is occupied by gas. The return pipeline is equipped with a pressure stabilizing valve 3 and a pressure sensor 4, which are used to control the opening and closing of the return pipeline and to measure the pressure pulsation signal of the return pipeline and feed it back to the control module.

[0038] The data acquisition module consists of a speed sensor that measures the speed of the aircraft and a flow meter that measures the flow rate in the jet pipe. The speed sensor is installed on the aircraft and the flow meter is installed on the jet pipe.

[0039] The programmable controller 8 stores data on the mapping relationship between different speeds and the optimal jet rate.

[0040] The polymer jetting rate varies with the sailing speed according to Figure 3 Curve adaptive adjustment. The plunger pump 8 is chosen for two reasons: first, it overcomes the high pressure underwater to eject the polymer from the injection outlet 5; second, it reduces polymer degradation due to shearing. The inlet 14 of the storage chamber 15 is connected to seawater, and the outlet is connected to the plunger pump inlet 2. This design ensures that the total amount of polymer ejected is the same as the amount flowing into the storage chamber, thus not affecting the buoyancy of the underwater vehicle. The speed sensor 1 senses the underwater vehicle's speed and sends the information to the programmable controller 8. Then, based on the speed and optimal injection rate relationship stored in the programmable controller 8, it sends a speed control command to the motor 9. The motor 9 is connected to the main shaft of the plunger pump 10 via a coupling, thereby controlling the injection rate of the injection outlet 7 by changing the rotational speed of the plunger pump 10. The flow meter 16 connected in the pipeline feeds back the injection flow information to the programmable controller 8, ensuring that the calculated nozzle injection rate matches the actual rate. Valves 3, 6, 11, and 12 are all controlled by the programmable controller 8 to control the opening and closing of the valves under different operating conditions. The pressure stabilizing chamber 5 is equipped with a pressure stabilizing chamber valve 3 and a pressure sensor 4 on the return pipe. The programmable controller 8 monitors the pressure pulsation signal obtained by the pressure sensor 4 in real time and makes real-time adjustments to the pressure stabilizing chamber valve 3 to return the pulsating flow in the pipeline to the liquid storage chamber 15, thereby reducing the interference caused by the vibration of the motor, plunger pump, valve and other components when they change their own state or during start-up and shutdown.

[0041] The programmable controller 8 stores the correspondence between sailing speed and jet rate in advance. When the speed-adaptive jet drag reduction method is used for underwater vehicles, its specific implementation follows these steps: a) The programmable controller 8 controls valves 3, 6 and 11 to close, valve 12 to open, and the external pump is connected to the polymer inlet 13 to inject a 100ppm PEO solution into the storage chamber. The seawater inlet 14 is in the drainage state at this time. b) After the PEO solution is injected, the programmable controller 8 sends a command to the polymer inlet valve 12 to control the polymer inlet 13 to close, while valves 6 and 11 open, the motor 9 runs, and the PEO solution is sprayed out from the spray outlet 7. c) The programmable controller 8 receives the sailing speed signal from the speed sensor 1 and calculates the current jet rate Qs based on the optimal mapping relationship between sailing speed and jet rate. Given the displacement v of the plunger pump 10 and the spanwise length L of the underwater vehicle's drag-reducing surface, the rotational speed n = L of the motor 9 can be calculated. Qs / v, then the programmable controller 8 sends a speed control command to the motor 9, and the PEO solution passes through the flow meter 16, the pressure stabilizing chamber 5 and the injection outlet valve 6 and is sprayed out from the injection outlet 7; d) If the flow rate value fed back to the programmable controller 8 by the flow meter 16 deviates from the calculated value, the programmable controller 8 will fine-tune the motor 9 until the actual spray rate of the nozzle is equal to the calculated value, and then the programmable controller 8 will stop issuing execution instructions. e) The pressure stabilizing chamber 5 performs the final pressure stabilization treatment on the ejected PEO solution. The programmable controller 8 monitors the pressure pulsation signal obtained by the pressure sensor 4 in real time and makes real-time adjustments to the pressure stabilizing chamber valve 3 to return the pulsating flow in the pipeline to the liquid storage chamber 15. At the same time, the compressed air in the pressure stabilizing chamber 5 further absorbs the pulsating pressure, reducing the interference caused by the vibration of the motor and valve or the moment of start-stop when they change their own state. f) After completing the adaptive jet drag reduction with speed, in order to prevent leakage of PEO solution in the reservoir 15, the programmable controller 8 sends a closing command to valves 3, 6 and 11.

[0042] In this embodiment, the drag reduction rate was tested at five different sailing speeds: 1 m / s, 2 m / s, 3 m / s, 4 m / s, and 5 m / s. The same condition was measured five times repeatedly, and the average value was taken. The results are as follows: Figure 3 As shown, by finely adjusting the jet rate at different sailing speeds, the drag reduction rate is basically maintained at 35%, achieving a highly efficient and stable drag reduction effect.

[0043] Example 2: The adaptive jet drag reduction method and system according to speed in this embodiment are the same as those in Embodiment 1, except that the connection position of the pressure stabilizing chamber is different.

[0044] The pressure stabilizing chamber 5 is connected in series with the injection pipeline and is connected to the liquid storage chamber 15 through the return pipeline. The two ports of the injection pipeline connected in series and the port connected to the return pipeline are all located below the liquid surface of the polymer solution in the chamber, while the liquid surface is filled with gas. The return pipeline is equipped with a pressure stabilizing chamber valve and a pressure sensor, which are used to control the opening and closing of the return pipeline and to measure the pressure pulsation signal of the return pipeline and feed it back to the control module.

[0045] The above two embodiments of the speed-adaptive jetting drag reduction method can be applied to underwater vehicles. Given a fixed total amount of polymer carried by the underwater vehicle, the jetting rate of the polymer can be adjusted in real time according to the vehicle's speed, achieving speed-adaptive jetting to maintain a long-term, high-efficiency jetting state and reduce pressure fluctuations during polymer jetting, thereby minimizing interference with the underwater vehicle's navigation. This speed-adaptive jetting drag reduction method is of great significance for improving the speed and range of underwater vehicles and has significant engineering application value in the field of polymer jetting drag reduction for underwater vehicles.

[0046] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A speed-adaptive jet drag reduction method, characterized in that... The specific steps are as follows: Install data acquisition modules on the aircraft; The real-time speed of the vehicle and the flow rate of the polymer jet are obtained by the data acquisition module; The control module receives and analyzes the information acquired by the data acquisition module, compares it with the optimal mapping relationship between speed and jet rate, obtains the calculated value of the jet rate corresponding to the measured speed, and then outputs control commands to the drive module to adjust the actual value of the polymer jet rate until it is equal to the calculated value. The drive module draws the polymer solution from the storage module to the polymer spray outlet for ejection, and the solution passes through the pressure stabilizing module; the pressure stabilizing module absorbs pressure fluctuations during polymer spraying. The pressure stabilizing module includes a pressure stabilizing chamber, a return pipeline connecting the pressure stabilizing chamber to the liquid storage module, a pressure sensor for measuring pressure pulsation signals in the return pipeline, and a pressure stabilizing chamber valve for controlling the on / off state and flow rate of the pressure stabilizing chamber. The pressure stabilizing chamber is connected to the injection pipeline between the drive module and the polymer solution injection outlet. By utilizing the compressibility of air within the chamber, it absorbs pulsating pressure to stabilize the injection pressure of the polymer solution.

2. A system for implementing the adaptive jet drag reduction method according to claim 1, characterized in that: It includes a control module, a data acquisition module, a drive module, a voltage regulator module connected to it, a liquid storage module for storing polymer solutions, and a spray pipeline; The liquid storage module maintains the buoyancy of the vehicle by communicating with seawater; The data acquisition module is installed on the vehicle and is used to collect the vehicle's real-time speed and the flow rate of the polymer jet. The control module receives and analyzes the information acquired by the data acquisition module and outputs control commands to the drive module; The drive module adjusts the flow rate according to the command, drawing the polymer solution in the liquid storage module into the spray pipeline, and then spraying it out from the spray outlet; a spray outlet valve is provided at the spray outlet to control the on / off state and the flow rate. The pressure stabilizing module is connected to the injection pipeline and is used to absorb pressure fluctuations when the polymer solution is ejected.

3. The implementation system according to claim 2, characterized in that: The liquid storage module includes a liquid storage chamber, a polymer inlet valve for controlling the opening and closing of the polymer inlet, and a seawater inlet connected to seawater; the liquid storage chamber is provided with a polymer inlet, a pipe connected to the seawater inlet, and an outlet connected to the drive module.

4. The implementation system according to claim 3, characterized in that: The drive module includes a motor, a plunger pump, and a plunger pump inlet valve. The motor is connected to the plunger pump main shaft via a coupling. The plunger pump inlet is connected to the outlet of the liquid storage chamber, and a plunger pump inlet valve is provided on the connecting pipeline. The plunger pump outlet is connected to the inlet of the injection pipeline.

5. The implementation system according to claim 4, characterized in that: The pressure stabilizing module includes a pressure stabilizing chamber. The input port of the pressure stabilizing chamber is connected to the injection pipeline, and the output port is connected to the liquid storage chamber through the return pipeline. Both the input and output ports are located below the liquid surface of the polymer solution in the chamber, while the liquid surface is occupied by gas. The return pipeline is equipped with a pressure stabilizing chamber valve and a pressure sensor, which are used to control the opening and closing of the return pipeline and to measure the pressure pulsation signal of the return pipeline and feed it back to the control module.

6. The implementation system according to claim 4, characterized in that: The pressure stabilizing module includes a pressure stabilizing chamber connected in series with the injection pipe and connected to the liquid storage chamber via a return pipe. The two ports of the injection pipe connected in series and the port connected to the return pipe are all located below the liquid surface of the polymer solution in the chamber, while the liquid surface is occupied by gas. The return pipe is equipped with a pressure stabilizing chamber valve and a pressure sensor, which are used to control the opening and closing of the return pipe and to measure the pressure pulsation signal of the return pipe and feed it back to the control module.

7. The implementation system according to claim 2, characterized in that: The data acquisition module includes a speed sensor for measuring the speed of the aircraft and a flow meter for measuring the flow rate in the jet pipe; the speed sensor is installed on the aircraft and the flow meter is installed on the jet pipe.

8. The implementation system according to claim 2, characterized in that: The control module is a programmable controller, which stores the optimal mapping relationship data between different speeds and the optimal jet rate.

9. The application of a system for implementing the adaptive jet drag reduction method according to any one of claims 5-8 on an aircraft, characterized in that: Install the aforementioned implementation system on the aircraft; The programmable controller controls the pressure regulating chamber valve, the jet outlet valve, and the plunger pump inlet valve to close, while the polymer inlet valve opens; then, an external pump injects polymer solution into the storage chamber, at which point the seawater inlet is in a draining state. After the polymer solution is filled, the programmable controller controls the polymer inlet valve to close, while simultaneously opening the jet outlet valve and the plunger pump inlet valve, and starts the motor. The motor speed is controlled by the programmable controller. The polymer solution passes through the flow meter, the pressure stabilizing chamber and the jet outlet valve in sequence and is then ejected from the jet outlet. The programmable controller receives the navigation speed signal from the speed sensor, normalizes the injection rate of the polymer solution, and uses Q... i / Q s It means that Q i Q is the injection rate. s Q is the volumetric flow rate per unit span of the viscous sublayer. s =67.3υ, where υ is the kinematic viscosity of water; The corresponding jet rate Q is obtained based on the optimal mapping relationship between sailing speed and normalized jet rate. i The formula for calculating the motor speed n is as follows: n=L Q i / v Where L is the spanwise length of the surface of the underwater vehicle to be drag-reduced, and v is the displacement of the plunger pump. If the flow rate value fed back to the programmable controller by the flow meter deviates from the calculated value, the programmable controller will fine-tune the motor until the actual spray rate of the nozzle is equal to the calculated value, and then stop issuing control execution commands. The pressure stabilizing chamber stabilizes the pressure of the ejected polymer solution. The programmable controller monitors the pressure pulsation signal obtained by the pressure sensor in real time and adjusts the pressure stabilizing chamber valve in real time to return the pulsating flow in the return pipeline to the storage chamber. At the same time, the compressed gas in the pressure stabilizing chamber absorbs the pulsating pressure and reduces the interference caused by the vibration of the motor and valve or the moment of start-stop when they change their state. After completing the adaptive jet drag reduction based on speed, the programmable controller controls the closure of the pressure stabilizing chamber valve, the jet outlet valve, and the plunger pump inlet valve to prevent leakage of the polymer solution in the storage chamber.

Images