Double-channel water-jet propeller and control method thereof

Abstract

The invention relates to a double-flow-channel water-jet propeller and a control method thereof.The double-flow-channel water-jet propeller comprises a water inlet flow channel connected into an inner cabin of a ship body, and one end of the water inlet flow channel is attached to a ship bottom plate; the water spraying propulsion pump is connected with the other end of the water inlet flow channel, is integrated with a rotatable impeller, drives water flow to be sprayed out backwards in an accelerated mode through rotation, and is internally provided with a rectification and steering adjusting mechanism so as to optimize the water flow direction and recycle rotation kinetic energy; wherein the water inlet flow channel comprises a main flow channel and a sub-flow channel, a water inlet communicated with the main flow channel and the sub-flow channel is formed in the ship bottom plate, the main flow channel is arranged in a normally open mode and has a smooth angle, and the sub-flow channel can be controlled to be opened and closed and has a large angle. The water-jet propulsor is compact and reasonable in structure and convenient to operate, and the thrust performance, adaptability and safety of the water-jet propulsor are remarkably improved through the innovative double-flow-channel design, accurate sub-flow-channel water inlet control and an efficient sudden stop control method.

Description

Technical Field

[0001] The present invention relates to the technical field of ship propellers, and in particular to a two-channel water jet propeller and its control method. Background Art

[0002] In the field of ship propulsion technology, the inlet flow channel, as a key component connecting the bottom of the ship to the water jet pump, its design directly affects the propulsion performance of the water jet propeller. Traditional inlet flow channel designs often face a series of challenges, especially in terms of performance at different ship speeds. For ships pursuing high-speed navigation, their inlet flow channels usually adopt a long and slender design with a gentle transition to improve propulsion efficiency. However, this design is difficult to provide sufficient inlet flow at low ship speeds, resulting in a decline in the performance of the propeller and insufficient thrust. On the contrary, for low-speed and large-displacement watercraft, their inlet flow channels have a larger diameter and inclination angle. Although they can provide better inlet flow at low ship speeds, they are prone to flow separation at high ship speeds, increasing the displacement loss of the hull and the appendage resistance, which also affects the propulsion performance.

[0003] Therefore, how to design an inlet flow channel that can adapt to different ship speed requirements, maintain high-efficiency propulsion at high ship speeds, and provide sufficient inlet flow at low ship speeds has become a technical problem to be solved urgently.

[0004] In summary, there is an urgent need for an innovative inlet flow channel design and its control method to solve the technical problem of poor performance of traditional inlet flow channels at different ship speeds. This new design should be able to balance the propulsion efficiency at high ship speeds and the inlet flow requirements at low ship speeds, while providing a flexible and controllable inlet opening and closing mechanism to meet the propulsion requirements of the ship under different working conditions and improve the overall performance and safety.

[0005] Therefore, we propose a two-channel water jet propeller and its control method. Summary of the Invention

[0006] The applicant of the present invention aims at the shortcomings in the above-mentioned existing production technologies, and provides a two-channel water jet propeller and its control method. Through an innovative two-channel design, precise control of the inlet of the sub-channel, and an efficient emergency stop control method, the thrust performance, adaptability, and safety of the water jet propeller are significantly improved.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A two-channel water jet propeller, comprising:

[0009] An inlet flow channel, which is connected to the inner cabin of the ship, and one end of the inlet flow channel is attached to the ship bottom plate;

[0010] A water jet propulsion pump, which is connected to the other end of the water inlet channel and integrates a rotatable impeller. By rotation, it drives the water flow to accelerate and spray backward, and has a built-in rectification and steering adjustment mechanism to optimize the water flow direction and recover the rotational kinetic energy.

[0011] Among them, the water inlet channel includes a main channel and a sub-channel, and a water inlet communicating with the main channel and the sub-channel is opened on the ship bottom plate. The main channel is always open and has a gentle angle, while the sub-channel can be controlled to open and close and has a larger angle. The opening and closing of the sub-channel are adjusted in real time according to the sailing speed of the boat to improve the overall propulsion performance of the water jet propulsion device.

[0012] In one embodiment, water inlet control closing devices are arranged on both sides of the sub-channel. The device includes a slide plate, a slide rail, a connecting rod, a rack, a gear and a motor. The slide plate is fixed to the rack through the connecting rod, and the motor drives the gear to rotate, thereby driving the rack and the slide plate to slide on the slide rail to realize the opening and closing of the water inlet.

[0013] In one embodiment, a channel penetrating the thickness of the ship bottom is provided on the ship bottom to accommodate the connecting rod and allow it to move with the slide plate while maintaining the structural integrity of the hull.

[0014] In one embodiment, a sealed cabin is further included. The sealed cabin is watertightly connected to the ship bottom and wraps the channel, the connecting rod, the rack, the gear and the motor to prevent water flow from entering the cabin through the channel.

[0015] In one embodiment, a lip seal is provided on the rotating shaft of the motor to prevent the water flow in the sealed cabin from entering the cabin through the rotating shaft.

[0016] In one embodiment, the main channel has a slender and gently transitional shape, which is suitable for high-speed navigation conditions.

[0017] In one embodiment, the main channel and the sub-channel are arranged front and back along the water inlet direction of the water inlet channel. The sub-channel is fully open at low sailing speeds to increase the inflow and increase the thrust; it is fully closed at high sailing speeds to avoid negative thrust caused by water flow impact.

[0018] In one embodiment, a control device is further included. The control device controls the movement of the motor according to the sailing speed of the ship to automatically adjust the opening and closing state of the water inlet of the sub-channel.

[0019] In one embodiment, the water jet propulsion pump includes:

[0020] A rotor, which includes a rotatable impeller. By rotation, it does work to drive the water flow to accelerate and spray backward;

[0021] A stator, which rectifies the rotating water flow formed by the rotor doing work and recovers the rotational kinetic energy;

[0022] A steering nozzle, connected to the stator outlet, for adjusting the jet direction;

[0023] And,

[0024] A reverse navigation bucket, arranged inside the steering nozzle, to obtain a reverse driving force by changing the angle of the reverse navigation bucket.

[0025] A control method for a two - flow - path water jet propeller as claimed in the claims, including the following control methods:

[0026] Control method for starting and operating at low speed:

[0027] Start the water jet propeller, and the water flow enters the propulsion pump through the main flow path;

[0028] When the ship is at low speed, open the water inlet of the sub - flow path through the control device, so that the water flow enters the propulsion pump from both the main flow path and the sub - flow path simultaneously, increasing the inflow and improving the thrust;

[0029] Control method for high - speed operation:

[0030] Monitor the ship's sailing speed as the ship's speed increases;

[0031] When the sailing speed reaches the preset critical speed, the control device drives the motor to close the water inlet of the sub - flow path. After closing the water inlet, the high - speed water flow in the main flow path forms positive and negative thrusts that cancel each other out in the sub - flow path;

[0032] Emergency stop control:

[0033] When an emergency stop is required at high speed, the control device quickly commands the motor to reverse or takes other means to move the slide along the slide rail to open the water inlet of the sub - flow path;

[0034] Utilize the negative thrust generated by the water flow impacting the sub - flow path, and through the cooperation of the reverse navigation bucket and the sub - flow path, jointly brake to reduce the braking distance and time of the boat.

[0035] The beneficial effects of the present invention are as follows:

[0036] The structure of the present invention is compact, reasonable, and easy to operate. Through the innovative two - flow - path design, precise control of the water inlet of the sub - flow path, and efficient emergency stop control method, the thrust performance, adaptability, and safety of the water jet propeller are significantly improved. This new type of water jet propeller not only solves the problems existing in the traditional technology but also provides new ideas and directions for the development of ship propulsion technology.

[0037] At the same time, the present invention also has the following advantages:

[0038] Improve thrust at low speeds: By adding sub-channels and opening them at low speeds, more inflow is provided for the water jet propeller, thus increasing the thrust. This enables low-speed, large-displacement vessels such as bridging boats, barges, and amphibious vehicles to obtain sufficient thrust at low speeds to overcome resistance and sail smoothly.

[0039] Maintain good propulsion performance at high speeds: At high speeds, by closing the inlet of the sub-channel, the adverse effect of the negative thrust generated by the water flow impacting the sub-channel on the performance of the propeller is avoided. At the same time, the mechanism of the positive and negative thrusts canceling each other out formed by the high-speed water flow in the main channel within the sub-channel enables the dual-channel water jet propeller to have the same good propulsion performance as a single-channel water jet propeller at high speeds.

[0040] Enhance the ability of the boat to stop and start suddenly: Open the sub-channel at low speeds to increase thrust and improve the acceleration speed; when making a sudden stop at high speeds, open the sub-channel to utilize the negative thrust to reduce the braking distance and time. This design not only improves the maneuverability of the boat but also enhances its safety and reliability.

[0041] Strong adaptability: Through intelligent control equipment, the opening and closing state of the inlet of the sub-channel is automatically adjusted according to the sailing speed of the ship, enabling the water jet propeller to adapt to the working conditions at different speeds. This design improves the adaptability and flexibility of the water jet propeller, enabling it to be widely used in various types of ships and watercraft.

[0042] Simple and reliable structure: The water jet propeller in this embodiment uses a mechanical transmission method to control the movement of the slide plate, with a simple and reliable structure that is easy to maintain. At the same time, the design of the sealed cabin and lip seal also ensures the safe operation and reliability of the ship. Brief Description of the Drawings

[0043] Figure 1 This is the front view of the present invention.

[0044] Figure 2 This is the three-dimensional structure schematic diagram of the present invention.

[0045] Figure 3 This is the schematic diagram of the slide plate movement structure in the present invention.

[0046] Figure 4 This is the connection structure schematic diagram of the slide plate movement structure and the sealed cabin in the present invention.

[0047] Figure 5 This is the schematic diagram of the motor shaft seal in the present invention.

[0048] Figure 6 This is the total thrust broken line graph of the water jet propeller under different channels in the present invention.

[0049] Figure 7It is a line graph of thrust deviation of single flow channel and double flow channel of the present invention.

[0050] Figure 8 It is a schematic diagram of the inflow condition of the dual-channel waterjet propulsion system of the present invention under mooring conditions.

[0051] Figure 9 This is a schematic diagram of the flow channel pressure distribution after the water inlet is released according to the present invention.

[0052] Figure 10 This is a schematic diagram of the flow channel pressure distribution after the water inlet is closed in the present invention.

[0053] Figure 11 This is a schematic diagram of the internal flow conditions after the sub-flow channel at the water inlet is closed in the present invention.

[0054] in:

[0055] 1. Bottom plate; 2. Water inlet channel; 3. Shaft system; 4. Rotor; 5. Stator; 6. Steering nozzle; 7. Inverted buoy; 8. Main channel; 9. Sub-channel; 10. Water inlet; 11. Slide rail; 12. Slide plate; 13. Connecting rod; 14. Rack; 15. Gear; 16. Motor; 17. Groove; 18. Sealed cabin; 20. Rotating shaft; 21. Lip seal. DETAILED DESCRIPTION

[0056] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0057] Embodiment 1

[0058] like Figure 1 As shown, this embodiment discloses a dual-channel waterjet propulsion device, the structure of which is an ingenious combination of a water inlet channel 2 and a waterjet propulsion pump arranged on the bottom plate 1 of the ship. The water inlet channel 2 is a key link between the hull cabin and the waterjet propulsion pump, and its design is directly related to the overall performance of the propulsion device. One end of the water inlet channel 2 is tightly fitted to the bottom plate 1 of the ship to ensure that the water flow can enter smoothly, while the other end is closely connected to the waterjet propulsion pump, forming an efficient water flow transmission system.

[0059] The water jet propulsion pump integrates a rotatable impeller, which is the core power source for accelerating the ejection of water flow. Through the rotation and work of the impeller, the water flow is given the kinetic energy to accelerate backward, thereby pushing the boat forward. More notably, a rectification and steering adjustment mechanism is ingeniously built inside the water jet propulsion pump. This mechanism can not only optimize the ejection direction of the water flow to ensure that the boat can travel along the predetermined route, but also effectively recover the rotational kinetic energy generated during the rotation of the impeller, improving the energy utilization efficiency. The design of the rectification and steering adjustment mechanism not only makes the water jet more concentrated and stable, reducing energy dissipation, but also further enhances the working efficiency of the propulsion pump by recovering the rotational kinetic energy. This design concept reflects the pursuit of efficient energy utilization and is of great significance for improving the endurance of the boat and reducing energy consumption.

[0060] Among them, the innovative design of the water inlet passage 2 is particularly remarkable. It adopts a double-channel structure, namely the combination of the main channel 8 and the sub-channel 9. The main channel 8, as a conventional design, has a slender and gently transitioning shape, ensuring that the water flow can pass smoothly under high-speed navigation conditions and providing stable propulsion force. The sub-channel 9, on the other hand, serves as a supplement to the main channel. Its larger-angle design can provide more inflow for the water jet propeller at low speeds, thereby significantly increasing the thrust. This double-channel design can precisely adapt to the boat's navigation speed by flexibly adjusting the opening and closing state of the sub-channel, improving the overall propulsion performance of the water jet propulsion device. The double-channel design fully considers the requirements of the boat at different navigation speeds and realizes the efficient utilization of water flow through the coordinated work of the main channel and the sub-channel. Especially under low-speed navigation conditions, the opening of the sub-channel provides additional inflow for the propeller, effectively solving the problem of insufficient thrust of traditional propellers at low speeds and enhancing the flexibility and adaptability of the boat.

[0061] As Figure 1 shown, although the names of key components such as the shafting 3, rotor 4, and stator 5 in this embodiment are not directly mentioned, their coordinated actions constitute the core part of the water jet propulsion pump. The rotor 4 contains a rotatable impeller, which is the key to accelerating the water flow; while the stator 5 is responsible for rectifying the rotating water flow formed by the work done on the rotor, recovering the rotational kinetic energy, and improving the energy utilization efficiency. The precise cooperation of components such as the shafting, rotor, and stator constitutes a complex power system, achieving the efficient utilization of water flow through precise transmission and energy conversion. This design not only improves the working efficiency of the propulsion pump but also extends the service life of the equipment by reducing energy losses.

[0062] In this embodiment, the same water inlet control and closing devices are arranged on both sides of the sub-channel, which enables the water inlet of the sub-channel 9 to be flexibly opened or closed as needed. When the two sliding plates 12 (as Figure 3When they slide to the middle of the slide rail 11 simultaneously (as shown), the water inlet 10 of the sub-channel 9 is blocked by the slide plate 12, and the sub-channel 9 is in a completely closed state. At this time, water flow cannot enter the sub-channel, avoiding the negative thrust generated by the impact of water flow on the sub-channel at high navigation speeds, thus improving the propulsion efficiency. When the two slide plates 12 slide to both ends of the slide rail 11, the slide plate 12 does not block the water inlet 10, and the sub-channel 9 is in a completely open state, allowing water flow to enter freely, providing sufficient inflow for the water jet propeller at low navigation speeds. The design of the water inlet control closing device reflects the refinement and intelligence of water flow control. By sliding the slide plate, the rapid and accurate opening and closing of the water inlet of the sub-channel can be achieved. This design not only improves the performance of the propeller but also enhances its ability to adapt to different navigation conditions. At the same time, the movement of the slide plate is driven by a motor, realizing the automatic control of the water inlet of the sub-channel and improving the reliability and ease of use of the equipment.

[0063] Compared with the prior art, through numerical simulation, it is found that when the water inlet 10 is in the normally open state, the thrust of the dual-channel water jet propeller in the mooring condition can be increased by about 10% compared with that when the sub-channel 9 is removed, as Figure 6 and Figure 7 shown. This result shows that the addition of the sub-channel 9 significantly improves the thrust of the water jet propeller at low navigation speeds, which is of great significance for improving the acceleration performance and flexibility of the boat. The display of the numerical simulation results provides strong data support for the performance advantages of the dual-channel water jet propeller. Compared with the design of removing the sub-channel, the thrust improvement effect of the dual-channel design at low navigation speeds is significant. This finding not only verifies the rationality of the dual-channel design but also provides an important reference basis for subsequent optimization design. At the same time, by comparing the thrust data under different working conditions, the performance characteristics of the propeller can be more intuitively understood, providing strong support for the design and selection of the boat.

[0064] In this embodiment, the movement of the slide plate 12 is driven by the motor 16, and this design realizes the precise control of the water inlet of the sub-channel. The slide plate 12 is fixed to the rack 14 through the connecting rod 13. The motor 16 drives the gear 15 to rotate, and then drives the rack 14 to translate, so that the slide plate 12 slides on the slide rail 11. This mechanical transmission method has the advantages of simple structure, reliable transmission, and easy control. The movement mechanism of the slide plate 12 driven by the motor 16 is the key to realizing the precise control of the water inlet of the sub-channel. Through the precise control of the motor, the rapid and accurate adjustment of the position of the slide plate can be achieved.

[0065] To ensure that the connecting rod 13 can move smoothly, a channel 17 penetrating the bottom plate 1 of the ship must be set along the movement trajectory of the connecting rod 13 at the bottom of the ship 1 (as Figure 4As shown). This design not only meets the movement requirements of the skateboard 12 but also ensures the structural integrity of the hull. The setting of the channel avoids the damage to the hull structure caused by the movement of the connecting rod and ensures the normal operation of the equipment.

[0066] In this embodiment, in order to prevent the water flow at the bottom of the ship from possibly entering the cabin through the channel 17, which poses a threat to the safe operation of the ship. A sealed cabin 18 is provided in the cabin in this embodiment. The sealed cabin 18 is watertightly connected to the ship bottom plate 1, enclosing the channel 17, the connecting rod 13, the rack 14, and the gear 15 to form a closed space. In this way, even if the water flow enters the inside of the sealed cabin 18 through the channel 17, it cannot further enter the cabin, ensuring the safe operation of the ship. It not only improves the safety of the ship but also enhances the reliability of the equipment, providing strong support for the long-term stable operation of the boat.

[0067] At the same time, the sealed cabin 18 also has sufficient space, enabling the rack 14 to move freely therein without being restricted by the wall surface of the sealed cabin. This design not only ensures the normal operation of the equipment but also improves the sealing performance of the cabin. The design of the sufficient space in the sealed cabin fully considers the operation requirements of the equipment and the sealing performance of the cabin. Through reasonable layout and planning, it not only ensures the free movement of components such as the rack but also avoids the intrusion of water flow into the cabin.

[0068] To further prevent water flow from entering the cabin, in this embodiment, a lip seal 21 is also used to seal the rotating shaft 20 of the motor 16 (as Figure 5 shown). The lip seal 21 has excellent sealing performance and wear resistance, and can effectively prevent the water flow in the sealed cabin 18 from entering the cabin through the rotating shaft 20. This design further improves the safety and reliability of the ship.

[0069] Embodiment 2

[0070] In this embodiment, a control method for a dual-channel water jet propeller is disclosed. This method covers multiple aspects such as the control of starting and operating at low speed, the control of high-speed operation, and the emergency stop control. The implementation of these control methods aims to improve the adaptability and performance of the water jet propeller to meet the requirements of the boat under different navigation conditions.

[0071] The control method for starting and operating at low ship speeds includes: starting the water jet thruster, and water flows into the propulsion pump through the main flow channel 8; when the ship is at low speed, the water inlet 10 of the sub-flow channel 9 is opened through the control device, so that water flows into the propulsion pump from both the main flow channel 8 and the sub-flow channel 9 simultaneously, increasing the inflow and enhancing the thrust. Under the low-speed working condition, the opening of the sub-flow channel provides additional inflow for the thruster, effectively solving the problem of insufficient thrust of traditional thrusters at low speeds. This control method realizes precise control of the thruster thrust by adjusting the opening and closing state of the sub-flow channel in real time, improving the acceleration performance and flexibility of the boat.

[0072] The main reason for the relatively large thrust of the dual-flow channel water jet thruster at low speeds is: under the low-speed working condition, the water jet thruster requires sufficient inflow to generate large thrust. However, due to the relatively small diameter of the main flow channel, it is difficult to provide sufficient inflow for the water jet propulsion pump at low speeds. At this time, the sub-flow channel, as a supplement to the main flow channel, provides more inflow for the water jet thruster, thereby increasing the thrust. As Figure 8 shown, at low speeds, after the inflow of the sub-flow channel converges with the inflow of the main flow channel, they jointly drive the water jet thruster to work. The coordinated operation of the sub-flow channel and the main flow channel is the key to enhancing the low-speed thrust of the water jet thruster. By reasonably designing the angle and size of the sub-flow channel, it is possible to ensure sufficient inflow for the thruster at low speeds. This design concept not only improves the performance of the thruster but also enhances the adaptability and flexibility of the boat.

[0073] However, as the ship speed increases, the inflow has greater kinetic energy, and the inflow that the main flow channel can provide will increase significantly. At this time, the role of the sub-flow channel in supplementing the inflow in enhancing the thruster thrust will gradually decrease. At the same time, the sub-flow channel also bears the impact of the water flow and has a certain negative thrust. Therefore, in the state where the water inlet is always open, the role of the sub-flow channel in enhancing the thruster performance will gradually weaken as the ship speed increases. Even when reaching a certain speed, when the negative thrust of the sub-flow channel is greater than the benefit brought by its supplementing inflow to the thruster, the sub-flow channel will reduce the propulsion performance of the water jet thruster. As the ship speed increases, the influence of the sub-flow channel on the thruster performance gradually changes. At high ship speeds, due to the significant increase in the inflow provided by the main flow channel, the role of the sub-flow channel in supplementing the inflow gradually weakens. At the same time, the negative thrust borne by the sub-flow channel also gradually increases, having an adverse impact on the thruster performance. Therefore, it is necessary to adjust the opening and closing state of the sub-flow channel in real time according to the change of the ship speed to optimize the thruster performance.

[0074] The control method for high-speed operation includes: monitoring the ship's navigation speed as the ship's speed increases; when the navigation speed reaches the preset critical speed, the control device drives the motor 16 to close the water inlet 10 of the sub-channel. After closing the water inlet, the high-speed water flow in the main channel forms a positive thrust and a negative thrust in the sub-channel that cancel each other out, maintaining the high-speed propulsion performance of the thruster. The control method at high speed aims to optimize the performance of the thruster by adjusting the opening and closing state of the sub-channel in real time. When the speed reaches the critical speed, by closing the water inlet of the sub-channel, it is possible to avoid the negative thrust borne by the sub-channel from having an adverse effect on the thruster performance. At the same time, the positive thrust and negative thrust formed by the high-speed water flow in the main channel in the sub-channel cancel each other out, maintaining the high-speed propulsion performance of the thruster.

[0075] This embodiment proposes a method of using the slide plate 12 to close the water inlet 10 of the sub-channel. When the ship's speed is higher than the critical speed (such as 17 knots), the motor 16 is driven to drive the slide plate 12 to close the water inlet 10 of the sub-channel. At this time, the bottom water flow of the ship cannot impact the sub-channel, and the pressure on the sub-channel will rapidly decrease. At the same time, the slider and the virtual wall surface of the main channel inlet form a relatively enclosed space, and the water flow in the sub-channel circulates slowly in the enclosed space (as Figure 11 shown). In this way, although the high-speed water flow inside the main channel will impact the left end of the sub-channel to form a negative thrust, this part of the water flow will move forward after acting on the left end wall surface of the sub-channel and impact the right end of the sub-channel to form a positive thrust. Since the negative thrust at the left end of the main channel is close to the positive thrust at the right end, the overall force on the sub-channel is almost 0 (as Figure 6 shown). Therefore, closing the water inlet of the sub-channel at high speed can make the dual-channel water jet thruster have the same good propulsion performance as the single-channel water jet thruster. The design of using the slide plate to close the water inlet of the sub-channel is an important attempt to optimize the thruster performance at high speed. By closing the water inlet, it is possible to avoid the negative thrust borne by the sub-channel from having an adverse effect on the thruster performance. At the same time, the positive thrust and negative thrust formed by the high-speed water flow in the main channel in the sub-channel cancel each other out, maintaining the high-speed propulsion performance of the thruster. This design concept reflects in-depth thinking and exploration of optimizing the thruster performance.

[0076] In order to achieve precise control of the slide plate 12 over the water inlet of the sub-channel, a control device for the motor 16 can be equipped on the ship. This device takes the ship's navigation speed as an input signal, judges whether the current speed is higher than the critical speed through a preset algorithm, and controls the movement of the motor 16 accordingly. When the ship's speed is lower than the critical speed, the control device drives the motor 16 to run to drive the two slide plates 12 to slide to both ends of the slide rail so that the water inlet 10 of the sub-channel is in a fully open state; when the ship's speed is higher than the critical speed, the motor is controlled to run to drive the two slide plates 12 to slide to the middle of the slide rail 11 so that the water inlet 10 of the sub-channel is in a fully closed state.

[0077] The critical speed is closely related to the ship and the water jet propeller and must be determined through tests or numerical simulations. In practical applications, tests or numerical simulations can be carried out based on the specific ship type and the design parameters of the water jet propeller to determine the optimal critical speed. By optimizing the setting of the critical speed, the propulsion efficiency and performance of the water jet propeller can be further improved. Through tests or numerical simulations, the performance of the propeller at different sailing speeds of the boat can be more accurately understood, so as to determine the optimal critical speed.

[0078] The emergency stop control method includes:

[0079] When an emergency stop is required at high sailing speeds, the control device quickly commands the motor 16 to reverse or takes other measures to move the slide plate 12 along the slide rail 11 to open the water inlet 10 of the sub-channel 9;

[0080] Utilize the negative thrust generated by the water flow impacting the sub-channel 9, and through the cooperation of the reverse navigation bucket 7 and the sub-channel 9, jointly brake to reduce the braking distance and time of the boat.

[0081] In addition, when making an emergency stop at high sailing speeds, opening the water inlet 10 can utilize the negative thrust borne by the sub-channel 9 to reduce the braking distance and time of the boat. This is because when the boat makes an emergency stop, due to inertia, the hull will still continue to move forward for a certain distance. At this time, if the water inlet of the sub-channel is opened to allow the water flow to impact the sub-channel to generate negative thrust, this negative thrust can be used to offset part of the inertial force, thereby shortening the braking distance and time. This design not only improves the maneuverability of the boat but also enhances its safety.

[0082] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention is referred to the claims, and within the protection scope of the present invention, any form of modification can be made.

Claims

1. A two-channel water jet propeller, characterized in that, Comprising: An inlet water passage, which is connected in the inner cabin of the ship's hull, and one end of the inlet water passage is attached to the ship's bottom plate; A water jet propulsion pump, which is connected to the other end of the inlet water passage and integrates a rotatable impeller. By rotating, it drives the water flow to accelerate and eject backward, and has a built-in rectification and steering adjustment mechanism to optimize the water flow direction and recover the rotational kinetic energy; Among them, the inlet water passage includes a main passage and a sub-passage, and a water inlet communicating with the main passage and the sub-passage is opened on the ship's bottom plate. The main passage is always open and has a gentle angle, while the sub-passage can be controlled to open and close and has a larger angle. The opening and closing of the sub-passage are adjusted in real time according to the sailing speed of the boat to improve the overall propulsion performance of the water jet propulsion device.

2. The dual-channel water jet propeller according to claim 1, characterized in that, On both sides of the sub-passage, there is an inlet control closing device, which includes a slide plate, a slide rail, a connecting rod, a rack, a gear and a motor. Among them, the slide plate is fixed to the rack through the connecting rod, and the motor drives the gear to rotate, thereby driving the rack and the slide plate to slide on the slide rail to realize the opening and closing of the water inlet.

3. The dual-channel water jet propulsor according to claim 2, characterized in that, A channel penetrating through its thickness is provided on the ship's bottom to accommodate the connecting rod and allow it to move with the slide plate while maintaining the structural integrity of the hull.

4. The dual-channel water jet propeller according to claim 3, wherein, It also includes a sealed cabin, which is watertightly connected to the ship's bottom and wraps the channel, the connecting rod, the rack, the gear and the motor to prevent water flow from entering the cabin through the channel.

5. The two-flow-channel water jet propeller according to claim 2, wherein, A lip seal is provided on the rotating shaft of the motor to prevent the water flow in the sealed cabin from entering the cabin through the rotating shaft.

6. The dual-channel water jet propulsor according to claim 1, characterized in that, The main passage has a slender and gently transitioning shape, suitable for high-speed navigation conditions.

7. The dual-channel water jet propulsor according to claim 1, wherein, The main passage and the sub-passage are arranged front and back along the water inlet direction of the inlet water passage. The sub-passage is fully open at low sailing speeds to increase the inflow and increase the thrust; it is fully closed at high sailing speeds to avoid the negative thrust generated by the water flow impact.

8. The dual-channel water jet propulsor according to any one of claims 1-7, characterized in that, It also includes a control device, which controls the movement of the motor according to the ship's sailing speed to automatically adjust the opening and closing state of the water inlet of the sub-passage.

9. The two-channel water jet propeller according to claim 8, characterized in that, The water jet propulsion pump includes: A rotor, which contains a rotatable impeller and drives the water flow to accelerate and eject backward by rotating to do work; A stator, which rectifies the rotating water flow formed by the rotor doing work and recovers the rotational kinetic energy; A steering nozzle, which is connected to the stator outlet and is used to adjust the jet direction; And, A reverse bucket, which is arranged inside the steering nozzle and obtains a reverse driving force by changing the angle of the reverse bucket.

10. A control method for a two-channel water jet propeller as claimed in claim 9, characterized in that, Including the following control methods: Control method for starting and operating at low speed: Start the water jet propeller, and the water flow enters the propulsion pump through the main passage; When the ship is at low speed, open the water inlet of the sub-passage through the control device, so that the water flow enters the propulsion pump from both the main passage and the sub-passage at the same time, increasing the inflow and improving the thrust; Control method for high-speed operation: As the ship's speed increases, monitor the ship's sailing speed; When the sailing speed reaches the preset critical speed, the control device drives the motor to close the water inlet of the sub-passage. After closing the water inlet, the high-speed water flow in the main passage forms a positive thrust and a negative thrust in the sub-passage, which cancel each other out; Emergency stop control: When an emergency stop is required at high speed, the control device quickly commands the motor to reverse or takes other means to move the slide plate along the slide rail to open the water inlet of the sub-passage; Utilize the negative thrust generated by the water flow impacting the sub-channel. Through the cooperation of the reverse navigation bucket and the sub-channel, jointly brake to reduce the braking distance and time of the boat.

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