An autonomous underwater equipment with adaptive cooling function

Abstract

To solve the problem that the cooling performance of the existing adaptive cooling scheme cannot meet the cooling and heat dissipation requirement of the propeller motor under certain speed points of high speed working condition of the underwater equipment, resulting in the reliability of the underwater equipment being reduced, and the qualitative consideration of the adaptive cooling is not conducive to achieving the long-range and long-time goals of the underwater equipment, the present application provides an underwater equipment with adaptive cooling function, comprising an adaptive cooling system, the inlet of the flow passage of the adaptive cooling system is arranged on the flow surface of the fin / convex of the underwater equipment shell, and the seawater can be introduced for cooling by using the hydrodynamic pressure. The higher the speed is, the more seawater is introduced, and the better the cooling effect is. Moreover, the structural parameters of the adaptive cooling system are determined by simulation optimization, the minimum seawater can be introduced to achieve the maximum cooling and heat dissipation capacity, and the situation that the cooling effect cannot meet the requirement under part of the speed can be avoided, which is conducive to improving the reliability, long-range and long-time goals of the underwater equipment.

Description

Technical Field

[0001] This invention relates to an underwater device with adaptive cooling function. Background Technology

[0002] As underwater equipment continues to develop towards higher speeds, the demand for high power density in propulsion motors is constantly increasing. Efficient cooling methods are one of the key technologies for improving the power density of propulsion motors. For high-power-density underwater propulsion motors, without effective cooling measures, the motor will rapidly overheat in a very short time, leading to irreversible damage such as insulation melting and permanent magnet demagnetization. Therefore, effective cooling methods are essential for high-power-density underwater propulsion motors.

[0003] Existing cooling solutions for underwater propulsion motors can be broadly categorized into two types: closed-loop cooling and open-loop cooling. Closed-loop cooling refers to a cooling method where seawater from outside the hull does not enter the underwater vehicle's interior. It typically uses a built-in circulating coolant that circulates within the motor's internal channels to cool it. Therefore, this method requires auxiliary equipment such as pumps and coolant tanks, resulting in a complex structure. Open-loop cooling, on the other hand, uses seawater drawn into the cooling channels by a pump. This method utilizes the seawater outside the hull and does not require heat exchange devices, but it also necessitates a pump to draw in the seawater. In summary, all existing cooling methods for underwater propulsion motors require a pump to power the coolant circulation within the channels, leading to complex structures.

[0004] To design simpler cooling systems for enclosed underwater equipment, some designers have proposed an adaptive cooling approach for heat-generating components using the hydrodynamic pressure of the underwater equipment during navigation. For example, patent document CN 113823859 B discloses an adaptive speed cooling system for an underwater vehicle's battery module. This system arranges the coolant inlet and outlet vertically, with seawater entering the cooling pipes by gravity. A flow regulating valve at the coolant inlet adaptively adjusts the inlet opening size according to the vehicle's speed; the higher the speed, the larger the opening, and vice versa. This adaptively adjusts the seawater flow rate into the cooling system, achieving speed-based cooling. However, this design requires an additional flow regulating valve protruding from the hull, inevitably affecting the underwater equipment's fluid profile. This increases drag and fluid noise, compromising the equipment's stealth and quietness.

[0005] In 2024, Ou Huanyu et al., in an article titled "Investigation of self-adjusting cooling system for the autonomous underwater vehicle propulsion motor" published in Volume 238, Issue 1 of the journal *Applied Thermal Engineering*, proposed a self-adjusting cooling system for the propulsion motor of an autonomous underwater vehicle. This system utilizes the pressure difference at the underwater vehicle's fins to introduce external seawater to cool the propulsion motor. As the vehicle's speed increases, the pressure difference at its fins also increases, resulting in a larger seawater flow rate and better cooling performance, thus achieving adaptive cooling. The paper also investigated the influence of the structural parameters of the cooling channel on heat dissipation performance to obtain the maximum seawater flow rate within the channel. However, we found that the increased seawater flow rate is not necessarily better. When the seawater flow rate increases to a certain level, it does not significantly improve the cooling performance. As a result, although the cooling performance of the cooling system improves with the increase of speed, there may still be situations where the cooling performance of the cooling system cannot meet the cooling and heat dissipation requirements of the propulsion motor at certain speed points under high-speed conditions. This leads to a decrease in the reliability of the propulsion motor, and consequently, a decrease in the reliability of the underwater equipment.

[0006] Furthermore, according to the law of conservation of energy, introducing seawater into the cooling channel will inevitably consume energy, and the greater the flow rate of seawater introduced, the greater the energy consumed by the cooling system. Therefore, an adaptive cooling system that only qualitatively considers the cooling effect and is designed according to the maximum flow rate is not conducive to achieving the overall goal of long range and long endurance of underwater equipment. Summary of the Invention

[0007] To address the issue that existing adaptive cooling solutions fail to meet the cooling and heat dissipation requirements of propulsion motors at certain speed points during high-speed operation of underwater equipment, thus reducing the reliability of the underwater equipment, and to resolve the technical problem that qualitatively considering adaptive cooling is not conducive to achieving the goals of long range and long endurance of underwater equipment, this invention provides an underwater equipment with adaptive cooling function.

[0008] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] An autonomous underwater vehicle with adaptive cooling function includes an underwater vehicle shell; the outer wall of the underwater vehicle shell has fins or protrusions.

[0010] Its special feature is:

[0011] The autonomous underwater vehicle also includes a propulsion motor and an adaptive cooling system;

[0012] The adaptive cooling system includes a motor cooling channel, a channel inlet, an inlet pipe, a channel outlet, and an outlet pipe.

[0013] The motor cooling channel is provided on the motor housing of the propulsion motor;

[0014] The flow channel inlet is located on the fin or the protruding frontal surface and is connected to the motor cooling flow channel through the inlet pipe; the flow channel outlet is located on the underwater equipment hull and is connected to the motor cooling flow channel through the outlet pipe.

[0015] The structural parameters of the adaptive cooling system are determined through simulation optimization so that the adaptive cooling system can achieve maximum cooling and heat dissipation capacity with minimal seawater introduction, and avoid situations where the cooling effect cannot meet the requirements at certain speeds.

[0016] Furthermore, it also includes a pressure valve disposed between the flow channel inlet and the inlet pipe; the pressure valve opens by fluid dynamic pressure, and the opening threshold is determined by the following method:

[0017] First, based on the structural parameters of the adaptive cooling system, the seawater flow rate Q entering the motor cooling channel is calculated. i Under the condition that = 0, different speeds v i The flow field outside the hull of the underwater equipment and the temperature field inside the propulsion motor were analyzed to obtain the corresponding pressure difference ΔP between the inlet and outlet of the motor cooling channel. i The highest temperature T of the main heat-generating components in the propulsion motor i ;

[0018] Then, based on the insulation class of the propulsion motor and considering a safety factor, the required safe temperature [T] of the propulsion motor is determined, and the results of the previous step are compared with the different speeds v. i The highest temperature T of the main heat-generating components in the propulsion motor i The opening threshold of the pressure valve is the highest temperature T, in addition to the required safe temperature [T]. i The pressure difference ΔP between the inlet and outlet of the motor cooling channel at the corresponding speed condition when the temperature is less than or equal to the safe temperature [T]. i .

[0019] Furthermore, the opening threshold of the pressure valve is the highest temperature T. i The pressure difference ΔP between the inlet and outlet of the motor cooling channel at the corresponding speed condition when it is less than and closest to the safe temperature [T]. i .

[0020] Furthermore, the structural parameters of the adaptive cooling system are specifically determined using the following optimization design method:

[0021] Step 1: Based on the structural parameters of each component of the propulsion motor, determine the range of values ​​for the structural parameters of the adaptive cooling system, including the structural parameters of the motor cooling channel, the channel inlet structural parameters, and the channel outlet parameters, and set the selection step size for the structural parameters of the adaptive cooling system;

[0022] Step 2: Based on the structural parameters of the adaptive cooling system, select a set of initial values ​​for the structural parameters from the range of values ​​determined in Step 1;

[0023] Step 3: Based on the selected initial values ​​of structural parameters, calculate different speeds v using a set speed step size. i The flow field and temperature field under the operating conditions were obtained, and thus the results were obtained at different cruising speeds v. i Seawater flow rate Q flowing into the motor cooling channel i The highest temperature T of the heat-generating components in the propulsion motor i ;

[0024] Step 4: Determine the speed at which the ship is sailing. i The highest temperature T of the heat-generating components in the down thrust motor i If the motor design requirements are not met, then fine-tune the structural parameters within the range of values ​​determined in step 1 and return to step 3; if yes, proceed to step 5.

[0025] Step 5: Calculate the weighted average seawater flow rate Q for all interested navigation speeds. avg It also saves the structural parameters of the current adaptive cooling system and the corresponding weighted average seawater flow rate Q. avg As a design sample point;

[0026] Step 6: Determine whether the range of structural parameters of the adaptive cooling system determined in Step 1 has been traversed. If not, return to Step 2 and continue to collect design sample points; if yes, the collection of design sample points is complete, and proceed to Step 7.

[0027] Step 7: Approximate the design sample points using a surrogate model, and employ an optimization algorithm to minimize the weighted average seawater flow rate Q. avg To optimize the objective, the optimization parameters are sought until the iteration converges and the optimal structural parameters of the adaptive cooling system are obtained.

[0028] Furthermore, the motor cooling channel is a spiral or axial Z-shaped cooling channel.

[0029] Furthermore, the surrogate model described in step 7 includes radial basis functions or Kriging.

[0030] Furthermore, the optimization algorithm described in step 7 includes a neural network optimization algorithm or a particle swarm optimization algorithm.

[0031] Furthermore, the pressure valve is a safety valve or a pressure reducing valve.

[0032] The beneficial effects of this invention are:

[0033] 1. This invention involves creating a flow channel inlet on the upstream surface of the fins / protrusions on the underwater equipment hull. Seawater is drawn into the motor cooling channel for cooling using the hydrodynamic pressure at the fins / protrusions. Because this invention eliminates the need for an additional flow regulating valve at the flow channel inlet, it does not disrupt the overall fluid profile of the underwater equipment and has no impact on its fluid performance. Therefore, it does not reduce the drag performance or stealth capabilities of the underwater equipment, and compared to existing adaptive cooling solutions, it offers superior drag performance and quieter operation.

[0034] Furthermore, the higher the speed, the greater the hydrodynamic pressure on the fins / protrusions, the more seawater flows into the cooling channels, and the better the cooling effect, thus enabling passive adaptive cooling.

[0035] Meanwhile, the structural parameters of the adaptive cooling system in this invention are determined by simulation optimization, which enables the adaptive cooling system to achieve maximum cooling and heat dissipation capacity with minimal seawater introduction, and avoids situations where the cooling effect cannot meet the requirements at certain speeds. This is beneficial to improving the reliability of underwater equipment and to achieving the goals of long range and long endurance of underwater equipment.

[0036] 2. We found that at low power output, when air cooling alone is sufficient to meet the heat dissipation requirements of the motor, drawing seawater is undoubtedly a waste of energy. Therefore, this invention adds a pressure valve between the inlet of the flow channel and the inlet pipe. When the propulsion motor does not require cooling at low underwater speeds, the fluid dynamic pressure on its fins is low and does not reach the opening threshold of the pressure valve. At this time, the pressure valve is closed, and seawater cannot flow into the cooling flow channel. This avoids the underwater equipment consuming energy due to the introduction of seawater, which helps to further improve the range and endurance of the underwater equipment. When the speed increases and the output power of the propulsion motor increases, the fluid dynamic pressure on the fins increases to a level sufficient to open the opening threshold of the pressure valve. The pressure valve automatically opens, allowing seawater to automatically flow into the cooling flow channel under the action of fluid dynamic pressure to cool the propulsion motor and ensure its reliable operation.

[0037] 3. The present invention also provides an optimized design method for an adaptive cooling channel. After optimizing the cooling channel using this method, the cooling system can meet the cooling and heat dissipation requirements of the motor at various speeds, avoiding situations where the cooling effect cannot meet the requirements at certain speeds, thus improving the reliability of underwater equipment. At the same time, the adaptive cooling system determined by this optimized design method can achieve maximum cooling and heat dissipation capacity with minimal seawater introduction, avoiding unnecessary energy consumption by the adaptive cooling system.

[0038] 4. This invention has good versatility and is applicable to underwater equipment such as torpedoes, underwater submersibles, AUVs and UUVs, whose hulls have fins or protrusions.

[0039] 5. This invention has low implementation cost but significant effect. By making low-cost improvements to existing underwater equipment with fins, it can achieve a comprehensive performance that balances cooling effect, energy consumption and quietness, and meet the technical requirements of high speed, long range, long endurance and quiet stealth of underwater equipment. Attached Figure Description

[0040] Figure 1 This is a partial half-sectional view of an autonomous underwater vehicle with adaptive cooling function according to an embodiment of the present invention.

[0041] Figure 2 This is a flow channel model of the adaptive cooling system in the autonomous underwater vehicle of this invention.

[0042] Figure 3 This is the optimized design process for the adaptive cooling system in the autonomous underwater vehicle of this invention.

[0043] Figure 4 This is a schematic diagram of the main design parameters of the adaptive cooling system in the autonomous underwater vehicle of this invention.

[0044] Figure 5 This is a flowchart illustrating the method for determining the opening threshold of the pressure valve in the adaptive cooling system of the autonomous underwater vehicle according to the present invention.

[0045] Figure label:

[0046] 1-Aircraft hull, 2-Propulsion motor, 3-Inlet pipe, 4-Flow channel inlet, 5-Pressure valve, 6-Fin plate, 7-Thruster, 8-Rudder plate, 9-Drive shaft, 10-Coupling, 11-Outlet pipe, 12-Flow channel outlet, 13-Motor cooling channel. Detailed Implementation

[0047] To make the technical solution of the present invention clearer, more understandable and easier to comprehend, the present invention will be further described in detail below with reference to the accompanying drawings.

[0048] Reference Figure 1-2 Taking an underwater vehicle as an example, the autonomous underwater equipment with adaptive cooling function provided in this embodiment of the invention includes a vehicle hull 1, a propulsion motor 2 and an adaptive cooling system disposed inside the vehicle hull 1, and a propulsion unit 7 disposed outside the vehicle hull 1 and driven by the propulsion motor 2.

[0049] The outer wall of the aircraft hull 1 has fins 6.

[0050] An adaptive cooling system is used to cool and reduce the temperature of the propulsion motor 2. The adaptive cooling system includes a spiral motor cooling channel 13 (in other embodiments, the motor cooling channel 13 may also be of other structural forms, such as axial Z-type), a channel inlet 4, an inlet pipe 3, a channel outlet 12, an outlet pipe 11, and a pressure valve 5.

[0051] The motor cooling channel 13 is provided on the motor housing of the propulsion motor 2.

[0052] The flow channel inlet 4 is located on the front surface of the fin 6 and is connected to the motor cooling flow channel 13 through the inlet pipe 3; the flow channel outlet 12 is located on the vehicle hull 1 and is connected to the motor cooling flow channel 13 through the outlet pipe 11.

[0053] Pressure valve 5 is installed between flow channel inlet 4 and inlet pipe 3. The inlet of pressure valve 5 is connected to flow channel inlet 4, and the outlet of pressure valve 5 is connected to inlet pipe 3. Pressure valve 5 can open and close according to heat dissipation requirements, thereby opening and closing motor cooling flow channel 13 to minimize or even avoid energy consumption of the adaptive cooling system while meeting heat dissipation needs. Pressure valve 5 can be a pressure reducing valve or a safety valve, and its specific structure can be selected from existing designs based on the opening threshold of pressure valve 5.

[0054] Reference Figure 5 The opening threshold of pressure valve 5 is determined according to the following method:

[0055] Based on the structural parameters of the optimized adaptive cooling system, Q is calculated. i Under the condition that = 0 (closed flow channel inlet), different speeds v i The flow field outside the hull 1 of the aircraft and the temperature field inside the propulsion motor 2 are used to obtain the corresponding pressure difference ΔP between the inlet and outlet of the motor cooling channel 13. i The highest temperature T of the main heat-generating components in the propulsion motor i ;

[0056] The required safe temperature [T] of propulsion motor 2 is determined based on its insulation class and a safety factor, and then compared with the different speeds v obtained in the previous step. i The highest temperature T of the main heat-generating components in the propulsion motor i The opening threshold of pressure valve 5 is the highest temperature T, in relation to the required safe temperature [T]. i The pressure difference ΔP between the inlet and outlet of the motor cooling channel 13 at the corresponding speed condition when the temperature is less than or equal to the safe temperature [T]. i .

[0057] When selecting the highest temperature T with the largest difference from the safe temperature [T], i The corresponding pressure difference ΔP iWhen using pressure valve 5 as the opening threshold, the lower the speed at which pressure valve 5 is opened; conversely, the lower the maximum temperature T that is selected with the smallest difference from the safe temperature [T], the better. i The corresponding pressure difference ΔP i The higher the speed at which pressure valve 5 is opened, the better. Ideally, the highest temperature T closest to the safe temperature [T] should be selected. i The corresponding pressure difference ΔP i Using the opening threshold of pressure valve 5, energy consumption can be minimized while ensuring that the motor heat dissipation meets the requirements.

[0058] The propulsion motor 2 and the propeller 7 are coaxially arranged. The output shaft of the propulsion motor 2 is connected to the transmission shaft 9 of the propeller 7 through the coupling 10, so as to transmit the output torque to the propeller 7.

[0059] The thruster 7 is used to drive the underwater equipment forward, backward, accelerate, and decelerate by utilizing the output torque of the propulsion motor 2.

[0060] The rudder plate 8 is connected to the vehicle hull 1 via a shaft and can rotate to change the navigation direction of the underwater vehicle.

[0061] The working principle of the autonomous underwater vehicle with adaptive cooling function of this invention is the same as that of existing underwater vehicles, and will not be described in detail here.

[0062] The autonomous underwater vehicle of this invention with adaptive cooling function activates and deactivates its adaptive cooling system according to the motor cooling requirements, and the adaptive cooling principle is as follows:

[0063] When the underwater equipment is sailing at low speed, the output power of the propulsion motor 2 is small, the temperature rise is small and there is no need for cooling. At this time, the fluid dynamic pressure at the inlet 4 of the flow channel is small and does not reach the opening threshold of the pressure valve 5. The pressure valve 5 is in the closed state. At this time, seawater will not flow into the motor cooling flow channel 13, which can reduce or even avoid the energy consumption caused by the introduction of seawater into the adaptive cooling system.

[0064] As the underwater equipment gradually increases its speed, the output power of the propulsion motor 2 gradually increases, and the temperature rises significantly, requiring cooling. Due to the gradual increase in speed, the hydrodynamic pressure on the upstream surface of the fin 6 gradually increases. When the hydrodynamic pressure reaches the opening threshold of the pressure valve 5, the pressure valve 5 can automatically open. Under the action of hydrodynamic pressure, seawater flows sequentially through the flow channel inlet 4, the pressure valve 5, the inlet pipe 3, and the motor cooling flow channel 13 to cool the propulsion motor 2, flows to the outlet pipe 11, and is finally discharged from the flow channel outlet 12 on the vehicle hull 1.

[0065] When the pressure valve 5 is opened and the underwater equipment speed is further increased, the output power of the propulsion motor 2 is greater, requiring stronger cooling capacity. Thanks to the increase in speed, the hydrodynamic pressure of the fin 6 on the front surface is further increased, which allows more seawater to be introduced to cool the propulsion motor 2. This achieves the purpose of adaptively increasing the seawater flow rate according to the motor output power to enhance the cooling capacity.

[0066] We note that, according to the law of conservation of energy, introducing seawater will inevitably consume the energy of underwater equipment to a certain extent. In order to minimize the amount of seawater introduced into the motor cooling channel 13 while meeting cooling requirements, thereby saving the energy of the underwater equipment and avoiding situations where the cooling effect cannot meet the requirements at certain speeds, this invention optimizes the design of the adaptive cooling system.

[0067] Reference Figure 3 Taking underwater vehicles and spiral-shaped motor cooling channels as examples, the process of optimizing the adaptive cooling system in this invention is as follows:

[0068] Step 1: Based on the structural parameters of each component of the propulsion motor 2, determine the range of values ​​for the structural parameters of the adaptive cooling system, and set the step size for selecting the structural parameters of the adaptive cooling system.

[0069] The structural parameters of the adaptive cooling system include those of the flow channel inlet 4, the motor cooling flow channel 13, and the flow channel outlet 12. For ease of parameter description, a coordinate system is defined in this embodiment: the axial direction of the underwater vehicle is defined as the x-axis, with the positive direction pointing towards the tail of the underwater vehicle; the y-axis is the radial direction of the flow channel half-section of the motor section housing, with the positive direction pointing towards the outside of the housing, as shown below. Figure 4 As shown in Table 1, the structural parameters of the adaptive cooling system are defined and their value ranges are as follows.

[0070] Table 1. Definitions and value ranges of structural parameters

[0071]

[0072]

[0073] Step 2: Based on the structural parameters of the adaptive cooling system, select a set of initial values ​​for the structural parameters from the range of values ​​determined in Step 1.

[0074] Step 3: Based on the selected initial values ​​of structural parameters, calculate different speeds v using a set speed step size. i The flow field and temperature field under the operating conditions, and the seawater flow rate Q flowing into the motor cooling channel 13. i The highest temperature T of the heating component in the propulsion motor 2 i .

[0075] Based on different sailing speeds v i (i is the operating condition number, i = 1, 2, 3, ..., m) The heat generation rate corresponding to the seawater flow velocity and motor output power under operating condition is modeled and calculated for different ship speeds v. i The flow field and temperature field under the current are used to obtain the different speeds v. i The seawater flow rate Q flowing into the motor cooling channel 13 i The highest temperature T of the heating component in the propulsion motor 2 i .

[0076] Step 4: Determine the speed at which the ship is sailing. i The highest temperature T of the heating component in the lower propulsion motor 2 i If the motor design requirements are not met, then fine-tune the structural parameters in Table 1 within the range of values ​​determined in step 1 and return to step 3; if the requirements are met, proceed to step 5.

[0077] Step 5: Calculate the weighted average seawater flow rate Q for all interested navigation speeds. avg It also saves the structural parameters of the current adaptive cooling system and the corresponding weighted average seawater flow rate Q. avg As a design sample point, Q avg The calculation formula is as follows:

[0078]

[0079] Where: m is the number of working conditions; t i Let t be the sailing time under the i-th working condition; t is the sum of the sailing times under all working conditions.

[0080] Step 6: Determine whether the range of structural parameters of the adaptive cooling system determined in Step 1 has been traversed. If not, return to Step 2 and continue to collect design sample points; if yes, the collection of design sample points is complete, and proceed to Step 7.

[0081] Step 7: In this embodiment, a Kriging surrogate model (or radial basis function in other embodiments) is used to approximate the design sample points, and a neural network algorithm (or particle swarm optimization in other embodiments) is used to minimize the weighted average seawater flow rate Q. avg To optimize the objective, the optimization parameters are sought until the iterations converge, at which point the optimal structural parameter design scheme for the adaptive cooling system is obtained. Table 2 below shows a comparison of the structural parameters before and after optimization in this embodiment.

[0082] Table 2 Comparison of parameters before and after optimization design

[0083] <![CDATA[Flow channel inlet diameter d c (mm)]]> 6 4 <![CDATA[Position X of the flow channel inlet in the x-axis direction i (mm)]]> 484 475 <![CDATA[Pitch Z of the spiral motor cooling flow channel c (mm)]]> 20 18 <![CDATA[Height h of the helical motor cooling flow channel c (mm)]]> 5 4 <![CDATA[Position X of the flow channel outlet in the x-axis direction o (mm)]]> 32 25 <![CDATA[Flow channel inlet angle α en (°)]]> 0 6 <![CDATA[Position H of the flow channel inlet in the y-axis direction en (mm)]]> 162 159 <![CDATA[Width W of the spiral motor cooling flow channel c (mm)]]> 12 15 <![CDATA[Flow channel outlet diameter d c (mm)]]> 6 4 <![CDATA[Weight-averaged seawater flow Q avg (L / min)]]> 4.8 4.2

[0084] By comparing the design results before and after optimization, it can be seen that the optimization design method proposed in this invention can effectively reduce the seawater flow rate introduced into the motor cooling channel, while simultaneously meeting the temperature requirements of the propulsion motor 2.

[0085] After optimizing the adaptive cooling system according to the method of this invention, the system can be optimized according to the final structural parameters determined by the optimization. Figure 5 The process shown determines the opening threshold of pressure valve 5. In this embodiment, the opening threshold of pressure valve 5 is determined to be 65 kPa.

[0086] The above description uses underwater vehicles and spiral-shaped motor cooling channels as examples to illustrate the present invention. The optimization methods for the above structure and adaptive cooling system are equally applicable to other underwater equipment, such as torpedoes and underwater submersibles. Furthermore, if the hull of the underwater equipment has protrusions, the channel inlet in the present invention can also be located on the upstream surface of the protrusion, rather than necessarily on the fin.

[0087] Finally, it should be noted that the above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art can adjust the above description to create other similar structural forms. It is neither necessary nor possible to exhaustively list all structures here. However, obvious variations and minor adjustments derived from the above are still within the scope of protection of this invention.

Claims

1. An autonomous underwater vehicle with adaptive cooling function, comprising an underwater vehicle shell; the outer wall of the underwater vehicle shell has fins or protrusions; Its features are: The autonomous underwater vehicle also includes a propulsion motor and an adaptive cooling system; The adaptive cooling system includes a motor cooling channel, a channel inlet, an inlet pipe, a channel outlet, and an outlet pipe. The motor cooling channel is provided on the motor housing of the propulsion motor; The flow channel inlet is located on the fin or the protruding frontal surface and is connected to the motor cooling flow channel through the inlet pipe; the flow channel outlet is located on the underwater equipment hull and is connected to the motor cooling flow channel through the outlet pipe. The structural parameters of the adaptive cooling system are determined using the following optimization design method: Step 1: Based on the structural parameters of each component of the propulsion motor, determine the range of values ​​for the structural parameters of the adaptive cooling system, including the structural parameters of the motor cooling channel, the channel inlet structural parameters, and the channel outlet parameters, and set the selection step size for the structural parameters of the adaptive cooling system; Step 2: Based on the structural parameters of the adaptive cooling system, select a set of initial values ​​for the structural parameters from the range of values ​​determined in Step 1; Step 3: Based on the selected initial values ​​of structural parameters, calculate different speeds v using a set speed step size. i The flow field and temperature field under the operating conditions were obtained, and thus the results were obtained at different cruising speeds v. i Seawater flow rate Q flowing into the motor cooling channel i The highest temperature T of the heat-generating components in the propulsion motor i ; Step 4: Determine the speed at which the ship is sailing. i The highest temperature T of the heat-generating components in the lower propulsion motor i Does it meet the motor design requirements? If not, fine-tune the structural parameters within the range of values ​​determined in step 1 and return to step 3. If so, proceed to step 5; Step 5: Calculate the weighted average seawater flow rate Q for all interested navigation speeds. avg It also saves the structural parameters of the current adaptive cooling system and the corresponding weighted average seawater flow rate Q. avg As a design sample point; m represents the number of operating conditions; t i Let be the duration of the voyage under the i-th operating condition; t is the sum of the sailing time under all operating conditions; Step 6: Determine whether the range of structural parameters of the adaptive cooling system determined in Step 1 has been traversed. If not, return to Step 2 and continue to collect design sample points; if yes, the collection of design sample points is complete, and proceed to Step 7. Step 7: Approximate the design sample points using a surrogate model, and employ an optimization algorithm to minimize the weighted average seawater flow rate Q. avg To optimize the objective, the optimization parameters are sought until the iteration converges and the optimal structural parameters of the adaptive cooling system are obtained.

2. The autonomous underwater vehicle with adaptive cooling function according to claim 1, characterized in that: It also includes a pressure valve disposed between the inlet of the flow channel and the inlet pipe; the pressure valve opens by fluid dynamic pressure, and the opening threshold is determined by the following method: First, based on the structural parameters of the adaptive cooling system, the seawater flow rate Q entering the motor cooling channel is calculated. i Under the condition that = 0, different speeds v i The flow field outside the hull of the underwater equipment and the temperature field inside the propulsion motor were analyzed to obtain the corresponding pressure difference ΔP between the inlet and outlet of the motor cooling channel. i The highest temperature T of the main heat-generating components in the propulsion motor i ; Then, based on the insulation class of the propulsion motor and considering a safety factor, the required safe temperature T for the propulsion motor is determined, and the different speeds v obtained in the previous step are compared. i The highest temperature T of the main heat-generating components in the propulsion motor i The opening threshold of the pressure valve is the maximum temperature T, which is the required safe temperature T. i The pressure difference ΔP between the inlet and outlet of the motor cooling channel at the corresponding speed condition when the temperature T is less than or equal to the safe temperature T. i .

3. The autonomous underwater vehicle with adaptive cooling function according to claim 2, characterized in that: The opening threshold of the pressure valve is the highest temperature T. i The pressure difference ΔP between the inlet and outlet of the motor cooling channel at the corresponding speed condition when it is less than and closest to the safe temperature T. i .

4. The autonomous underwater vehicle with adaptive cooling function according to any one of claims 1-3, characterized in that: The motor cooling channel is a spiral or axial Z-shaped cooling channel.

5. The autonomous underwater vehicle with adaptive cooling function according to claim 4, characterized in that: The surrogate model described in step 7 includes radial basis functions or Kriging.

6. The autonomous underwater vehicle with adaptive cooling function according to claim 5, characterized in that: The optimization algorithm mentioned in step 7 includes a neural network optimization algorithm or a particle swarm optimization algorithm.

7. The autonomous underwater vehicle with adaptive cooling function according to claim 2 or 3, characterized in that: The pressure valve is a safety valve or a pressure reducing valve.

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