An underwater vehicle with a built-in pump jet

Abstract

This invention discloses a built-in pump-jet underwater vehicle, comprising a hull, a storage compartment at the head of the hull, and a main propulsion mechanism at the tail. The storage compartment stores detection equipment and a battery pack. A water inlet is located between the front end of the main propulsion mechanism and the tail of the storage compartment, and a water jet nozzle is located at the rear end. A pump-jet propulsor is installed inside the main propulsion mechanism; water enters through the inlet, passes through the main propulsion mechanism, and is ejected through the water jet nozzle. Two auxiliary small propulsors are symmetrically arranged near the tail of the hull. This invention represents a novel combined propulsion method and propulsion structure. The built-in pump-jet structure reduces system noise. The use of polyethylene oxide turbulence drag reduction allows for a significant increase in thrust in a short time after the vehicle reaches its speed limit. The side-entry water intake shortens the flow channel, reducing overall drag. It is perfectly suited for use in special situations such as target tracking or escape from enemy attacks.

Description

Technical Field

[0001] This invention relates to the technical field of underwater vehicles, and in particular to a built-in pump-jet underwater vehicle. Background Technology

[0002] Unmanned underwater vehicles (UUVs) are crucial tools for accomplishing various underwater missions, with broad application prospects in both military and scientific research fields. The propulsion system is the primary power source of the UUV, and its efficiency and hydrodynamic noise are critical to its overall performance and stealth. Due to its high propulsion efficiency, strong anti-cavitation capability, and low radiated noise, axial-flow pump-jet propulsion is widely used in various types of UUVs. UUVs often operate with a wide speed range, such as 5 knots for exploration (long-duration operation), 9 knots for navigation, and 15 knots for emergency situations. This variable operating condition is typically achieved by adjusting the propulsion speed. However, because UUVs have long flow channels running from front to back, excessively high propulsion speeds can lead to cavitation and high noise levels, making it difficult for traditional pump-jet propulsion methods to simultaneously meet the requirements of rapid acceleration and low noise design. Summary of the Invention

[0003] The purpose of this invention is to provide a built-in pump-jet underwater vehicle to solve the problems existing in the prior art, so that the thrust limit of the vehicle can be increased instantaneously and the noise can be reduced.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a built-in pump-jet underwater vehicle, including a hull, a storage compartment disposed at the head of the hull, and a main propulsion mechanism disposed at the tail of the hull. The storage compartment stores detection equipment and a battery pack. A water inlet is disposed between the front end of the main propulsion mechanism and the tail end of the storage compartment, and a water jet is disposed at the rear end. A pump-jet propulsor is disposed inside the main propulsion mechanism. Water enters through the water inlet, passes through the main propulsion mechanism, and is ejected from the water jet.

[0006] Preferably, the main propulsion mechanism includes a rectifier channel and a pump-jet propeller, the rectifier channel is funnel-shaped, and the pump-jet propeller is fixed to the inner wall of the rectifier channel.

[0007] Preferably, the pump-jet propulsion device includes a motor, an impeller, a guide cone, and a rear guide vane. The motor shaft is connected to the impeller, the housing is connected to the guide cone, the front end of the housing is fixedly connected to the storage bin, and the rear end is connected to the inner wall of the main propulsion mechanism through the rear guide vane.

[0008] Preferably, a bearing is provided at each end of the motor shaft; the motor is a variable frequency motor with a frequency of 20Hz-100Hz and a speed of 400r / min-1450r / min.

[0009] Preferably, the rectifying channel is a double-layered shell with a cavity, and the inner wall of the rectifying channel includes a smoothly connected straight section and a conical section, the size of which gradually decreases and is located at the water outlet.

[0010] Preferably, at least one emergency accelerator is provided in the clamping cavity. The emergency accelerator includes a reagent tank, a drain pipe, and a solenoid valve. The drain pipe is provided on the reagent tank, and the solenoid valve is provided on the drain pipe. The reagent tank contains turbulence-reducing reagent.

[0011] Preferably, a piston plate is provided inside the reagent tank. One side of the piston plate is provided with a reagent chamber for the turbulence-reducing agent, and the other side is provided with a water inlet chamber. The water inlet chamber is provided with a water inlet hole, which is connected to the rectifier channel and located near the guide cone.

[0012] Preferably, the turbulence-reducing agent is polyethylene oxide, and after the solenoid valve is opened, the concentration of the turbulence-reducing agent in the rectifier channel is controlled at 75mg / L-100mg / L; the outlet of the drain pipe is located upstream of the impeller, and the distance between it and the impeller is no greater than 1 / 3 of the airfoil chord of the impeller blades.

[0013] Preferably, a pair of auxiliary thrusters are symmetrically arranged on the outer wall of the rectifier channel, and the distance between the auxiliary thrusters and the tail of the housing does not exceed 1 / 6 of the total length of the housing.

[0014] Preferably, two water inlets are symmetrically arranged on the housing, and the main propulsion mechanism is smoothly connected to the storage compartment.

[0015] The present invention achieves the following technical effects compared to the prior art:

[0016] This invention is a novel combined propulsion method and propeller structure. The side water intake of the vehicle reduces the overall resistance. The built-in pump-jet structure gives the system advantages such as low noise, light weight, and the ability to significantly increase thrust in a short time after the vehicle reaches its speed limit. It is perfectly suitable for use in special occasions such as target tracking or escape from the enemy. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Fig. 1 This is a schematic diagram of the structure of the built-in pump-jet underwater vehicle in an embodiment of the present invention;

[0019] Fig. 2 This is a schematic diagram of the casing structure in an embodiment of the present invention;

[0020] Fig. 3 This is a partial structural diagram of the traditional Chinese medicine preparation box in an embodiment of the present invention;

[0021] The components are: 1-storage compartment, 2-water inlet, 3-solenoid valve, 4-drain pipe, 5-chemical tank, 6-piston plate, 7-water inlet hole, 8-auxiliary propeller, 9-rectifier channel, 10-conical section, 11-straight section, 12-motor, 13-guide cone, 14-rear guide vane, 15-impeller, 16-bearing, 17-casing. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0023] The purpose of this invention is to provide a built-in pump-jet underwater vehicle to solve the problems existing in the prior art, so that the thrust limit of the vehicle can be increased instantaneously and the noise can be reduced.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figs. 1 to 3As shown: This embodiment provides a built-in pump-jet underwater vehicle, including a hull 17, a storage compartment 1 located at the head of the hull 17, and a main propulsion mechanism located at the tail of the hull 17. The storage compartment 1 stores detection equipment and a battery pack. A water inlet 2 is provided between the front end of the main propulsion mechanism and the tail end of the storage compartment 1, and a water jet nozzle is provided at the rear end. A pump-jet propulsion unit (main propulsion unit) is provided inside the main propulsion mechanism. The built-in pump-jet structure gives the system the advantage of low noise. Water enters through the water inlet 2, passes through the main propulsion mechanism, and is ejected through the water jet nozzle. This embodiment is equivalent to providing a water inlet 2 on the side of the vehicle body, which shortens the length of the internal flow channel, thereby reducing resistance, and also increases the internal cavity volume of the vehicle body, allowing it to accommodate more equipment.

[0026] Specifically, in this embodiment, the main propulsion mechanism includes a rectifier channel 9 and a pump-jet propeller. The rectifier channel 9 is funnel-shaped and functions as a rectifier tube. The pump-jet propeller is fixed to the inner wall of the rectifier channel 9 and uses an internal pump-jet structure to reduce noise. The pump-jet propeller includes a motor 12, an impeller 15, a guide cone 13, and a rear guide vane 14. A bearing 16 is provided at both ends of the shaft of the motor 12. The shaft of the motor 12 is connected to the impeller 15, and the housing is connected to the guide cone 13. The front end of the housing of the motor 12 is fixedly connected to the storage chamber 1, and the rear end is connected to the inner wall of the main propulsion mechanism through the rear guide vane 14. The rear guide vane 14 uses an airfoil structure and is directly connected to the inner wall of the rectifier channel. It has two functions: first, it allows the water flow to move along the axial direction as much as possible, which can reduce the generation of vortex areas and improve the flow pattern; second, it acts as a fixing frame to support the propulsion system inside the flow channel. Motor 12 is a variable frequency motor with a frequency of 20Hz-100Hz and a speed of 400r / min-1450r / min. The power lines of motor 12 are arranged along the outer wall of the motor stator and are waterproofed and sealed. In this embodiment, two water inlets are symmetrically arranged on the casing. The main propulsion mechanism and the storage compartment are smoothly connected, forming two elliptical water inlets, equivalent to two water inlets 2 arranged on the side of the vehicle. This effectively shortens the length of the water flow channel, reduces power loss, and lowers the overall resistance. The impeller 15 is positioned with the shaft shoulder of motor 12 by fixing bolts to prevent axial movement. The casing 17 of the vehicle has an average thickness of 35mm and can withstand underwater pressure of 3000m-4500m.

[0027] Specifically, in this embodiment, the rectifying channel 9 is a double-layered shell with a cavity. The rectifying channel 9 is hollowed out, which reduces the wall thickness while ensuring strength, further saving space and reducing the overall weight. The inner wall of the rectifying channel 9 includes a smoothly connected straight section 11 and a conical section 10. The size of the conical section 10 gradually decreases and is located at the water outlet, forming a rectifying channel 9. At least one emergency accelerator is installed in the cavity. The emergency accelerator includes a reagent tank 5, a drain pipe 4, and a solenoid valve 3. The reagent tank 5 is equipped with a drain pipe 4, and the drain pipe 4 is equipped with a solenoid valve 3. The reagent tank 5 contains turbulence reduction agent. A piston plate 6 is installed inside the reagent tank 5. One side of the piston plate 6 has a reagent chamber for the turbulence-reducing agent, and the other side has a water inlet chamber. The water inlet chamber has a water inlet hole 7 connected to the rectifier channel 9. The water inlet hole 7 is connected to the rectifier channel via a flow channel and is located near the guide cone 13. When the main thruster is running, a high fluid pressure is generated in the area of ​​the rear guide vane 14, which can push the piston plate 6 to expel the reagent. The turbulence-reducing agent is polyethylene oxide. After the solenoid valve 3 is opened, the concentration of the turbulence-reducing agent in the rectifier channel is controlled at 75mg / L-100mg / L. This turbulence-reducing agent is a water-soluble non-Newtonian fluid with a fast dissolution rate and no pollution. The discharge rate of polyethylene oxide can be controlled by adjusting the opening of the solenoid valve 3. The relationship between the opening and the discharge rate satisfies the following formula:

[0028] Q / Q max =(1 / R)[1+(R-1)L / L max ]

[0029] Q represents displacement; L represents valve opening; and R represents the adjustable ratio, which is the ratio of the maximum to the minimum flow rate that solenoid valve 3 can control. The seawater flow rate in the rectifier channel can be roughly calculated based on the real-time ship speed. By adjusting the opening of solenoid valve 3, the polyethylene oxide concentration in the rectifier channel can be controlled between 75 mg / L and 100 mg / L. Within this concentration range, the drag reduction effect is optimal.

[0030] The piston plate 6 has a reagent chamber on its front side and a high-pressure fluid (seawater) on its rear side. To ensure that the high-pressure fluid can effectively push the piston plate 6, the area of ​​the water inlet 7 must not be less than 1 / 8 of the area of ​​the rear plate of the water inlet chamber. When the vehicle needs to accelerate instantaneously, the drain pipe 4 can be opened by the solenoid valve 3. The polyethylene oxide inside mixes with the water flow, which can effectively change the viscosity of the fluid passing through the rectifier channel, thereby greatly reducing the flow resistance and allowing the instantaneous speed to increase rapidly. After acceleration, the drain pipe 4 can be closed by the solenoid valve 3, and the propeller can eventually return to the previous speed.

[0031] The outlet of the drain pipe 4 is located upstream of the impeller 15, and the distance between the outlet of the drain pipe 4 and the impeller 15 is no greater than 1 / 3 of the airfoil chord of the impeller 15 blades. This ensures that the mixed fluid can quickly enter the impeller 15 to achieve drag reduction and acceleration. In this embodiment, the drag reduction effect is generated by releasing the turbulence generated by the mixture of polyethylene oxide stored in the cabin and seawater, which allows the thrust limit of the vehicle to increase instantaneously, meeting the need to increase speed in emergency situations. Furthermore, since the propulsion unit is installed inside the vehicle, noise is significantly reduced. This embodiment utilizes the drag reduction effect of non-Newtonian fluid turbulence. A reagent tank 5 containing polyethylene oxide is installed on the rectifier pipe, and the opening is controlled by a valve. After the polyethylene oxide is injected into the rectifier channel 9 and mixed with seawater, the viscosity and resistance of the seawater are reduced, thereby increasing the flow rate through the pump in the same amount of time, increasing the reaction force, and increasing the thrust. A contraction-type outlet is used, which further accelerates the seawater by squeezing it through the outlet, generating even greater thrust. In this embodiment, the reagent tank 5 containing polyethylene oxide is installed above the rectifier channel 9, making full use of the internal space of the aircraft and making the structure more compact.

[0032] A pair of auxiliary thrusters 8 are symmetrically arranged on the outer wall of the rectifier channel 9. The auxiliary thrusters 8 are distributed on the left and right sides of the vehicle's forward direction. The distance between the auxiliary thrusters 8 and the tail of the fuselage 17 does not exceed 1 / 6 of the total length of the fuselage 17. The auxiliary thrusters 8 in this embodiment are conventional thruster structures in the art, which will not be described in detail here. In the navigation working state (9 knots speed), the two auxiliary thrusters 8 can assist the main thrusters in running together.

[0033] The underwater navigation system in this embodiment has a normal cruising speed of 5 knots, at which the system drag is 490 N. In normal cruising conditions (9 knots), the drag is 800 N; while in emergency conditions (15 knots), the drag is 1250 N. The drag reduction percentage after adding polyethylene oxide is calculated as follows:

[0034]

[0035] DR – Drag Reduction Ratio;

[0036] ΔP0—Basic frictional pressure drop (MPa) when no drag-reducing agent is added to the fluid;

[0037] ΔP DR —Frictional pressure drop (MPa) after adding drag-reducing agent.

[0038] The formula for calculating the increase rate is as follows:

[0039]

[0040] When the inlet pipe diameter is 7.8 mm, adding a 50 mg / L polyethylene oxide aqueous solution reduces drag by 63.5%. The thrust of a waterjet propeller can be expressed as the momentum increase of the fluid flowing through the propeller per unit time. When the propeller speed is 1000 r / min and the flow rate is 14 kg / s, it is calculated as follows:

[0041] T=ρQ(v j -v s (3)

[0042] It can be calculated that the thrust can be increased by 70% after using drag reducer, which means that the speed can be increased to 15 knots in a short time.

[0043] In this embodiment, the built-in pump-jet underwater vehicle (UUV) receives seawater through a side-mounted horn-shaped inlet 2, which flows into the main propulsion mechanism at the stern. The seawater then collects in the rectifying channel 9 and enters the impeller 15, where it is accelerated before exiting through a constricted outlet. During this process, a valve on the chemical tank 5 can be opened to release polyethylene oxide (PEO) as needed for speed. Due to the turbulent drag reduction effect of PEO, its viscosity decreases after mixing with seawater, reducing resistance and increasing the amount of fluid flowing into the pump within the same timeframe, thus achieving a significant increase in thrust in a short period. This embodiment, based on the principle of non-Newtonian fluid turbulent drag reduction, allows for rapid acceleration via the pump-jet propulsion system. This novel propulsion method can quickly exceed the design limits of the impeller 15, further increasing thrust and speed to meet the needs of extreme emergency navigation. It also reduces system noise and weight without affecting normal cruising speeds, solving the problem that traditional single-pump-jet propulsion systems cannot handle UUV navigation over a wide speed range.

[0044] This embodiment features two auxiliary small thrusters symmetrically distributed near the outer side of the tail section of the fuselage. During exploration operations (5 knots), the main thruster provides power. During navigation operations (9 knots), the two auxiliary thrusters assist the main thruster. In emergency situations (15 knots), polyethylene oxide released from the propellant tank alters the internal turbulence structure, significantly reducing flow resistance. Combined with the power provided by the three thrusters, this allows for a rapid increase in thrust and speed without increasing thruster speed. The release of polyethylene oxide within the cabin provides high thrust through the combined action of all thrusters. This embodiment represents a novel combined propulsion method and thruster structure. The built-in pump-jet structure results in low noise. The polyethylene oxide turbulence drag reduction effect allows for a significant increase in thrust even after reaching the speed limit. The side-entry water intake shortens the flow path, reducing losses and lowering overall drag. This design is suitable for special applications such as target tracking or escape from enemy attacks.

[0045] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A built-in pump-jet underwater vehicle, characterized in that: The device includes a housing, a storage compartment located at the head of the housing, and a main propulsion mechanism located at the tail of the housing. The storage compartment stores detection equipment and a battery pack. A water inlet is located between the front end of the main propulsion mechanism and the tail end of the storage compartment, and a water spray nozzle is located at the rear end. A pump-jet propulsor is installed inside the main propulsion mechanism. Water enters through the water inlet, passes through the main propulsion mechanism, and is sprayed out through the water spray nozzle. The main propulsion mechanism includes a rectifier channel and a pump-jet propulsion device. The pump-jet propulsion device includes a motor, an impeller, a guide cone, and a rear guide vane. The motor shaft is connected to the impeller, and the housing is connected to the guide cone. The front end of the housing is fixedly connected to the storage compartment, and the rear end is connected to the inner wall of the main propulsion mechanism through the rear guide vane. The rectifying channel is a double-layered shell with a cavity. The inner wall of the rectifying channel includes a smoothly connected straight section and a conical section. The size of the conical section gradually decreases and is located at the water outlet. At least one emergency accelerator is provided in the clamping cavity. The emergency accelerator includes a reagent tank, a drain pipe, and a solenoid valve. The drain pipe is provided on the reagent tank, and the solenoid valve is provided on the drain pipe. The reagent tank contains turbulence-reducing agents. The outlet of the drain pipe is located upstream of the impeller, and the distance between it and the impeller is no greater than 1 / 3 of the airfoil chord length of the impeller blades.

2. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: The rectifier channel is funnel-shaped, and the pump-jet propulsion unit is fixed to the inner wall of the rectifier channel.

3. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: A bearing is provided at each end of the motor shaft; the motor is a variable frequency motor with a frequency of 20Hz-100Hz and a speed of 400r / min-1450r / min.

4. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: A piston plate is provided inside the reagent tank. One side of the piston plate is provided with a reagent chamber for the turbulence-reducing agent, and the other side is provided with a water inlet chamber. The water inlet chamber is provided with a water inlet hole, which is connected to the rectifier channel and located near the guide cone.

5. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: The turbulence-reducing agent is polyethylene oxide, and after the solenoid valve is opened, the concentration of the turbulence-reducing agent in the rectifier channel is controlled at 75 mg / L-100 mg / L.

6. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: A pair of auxiliary thrusters are symmetrically arranged on the outer wall of the rectifier channel, and the distance between the auxiliary thrusters and the tail of the casing does not exceed 1 / 6 of the total length of the casing.

7. The built-in pump-jet underwater vehicle according to claim 1, characterized in that: The casing has two symmetrically arranged water inlets, and the main propulsion mechanism is smoothly connected to the storage compartment.

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