Combined hydrodynamic energy-saving and efficiency-improving system for ship stern

Abstract

The invention discloses a ship stern combined hydrodynamic energy-saving synergistic system which comprises a propeller, a pair of flow guide fins, a pair of rudder thrust fins and a pre-rotation fin, the pre-rotation fin is arranged on the port side of a ship stern casting in front of the propeller, and the pair of flow guide fins are arranged on the port side and the port side of a ship body in front of the pre-rotation fin in a mirror symmetry mode. And the pair of rudder thrust fins are rotationally connected with the ship body, are arranged on the left and right sides of the rudder behind the propeller in a mirror symmetry manner, and are rotationally connected with the rudder. According to the combined hydrodynamic energy-saving and efficiency-improving system for the ship stern, an energy-saving device can be adjusted in a self-adaptive mode according to the flow field form, and the utilization rate of the beneficial flow field is high; energy-saving devices are organically combined for use, so that the thrust efficiency is greatly improved; the energy-saving device is simple in structure and low in manufacturing and mounting difficulty and cost; the wake flow rotation degree is low, and the recovery and reutilization rate of wake flow rotation energy is high.

Description

Technical Field

[0001] The invention relates to the technical field of ship energy saving, and in particular to a ship stern combined hydrodynamic energy saving and efficiency enhancement system. Background Art

[0002] A hydrodynamic energy-saving device is an appendage installed in front of or behind a propeller, which is designed to improve the propulsion efficiency of the propeller and reduce the energy loss of the wake behind the propeller, thereby achieving the purpose of energy saving. The design and implementation of these devices are of great significance for the green modification of old ships and for responding to the increasingly stringent energy-saving and emission-reduction policies of the shipping industry. At present, the existing hydrodynamic energy-saving devices can be divided into energy-saving devices behind the propeller and energy-saving devices in front of the propeller according to the installation position at the stern of the ship. On the one hand, most of these two types of energy-saving devices are used independently, which leads to the failure of organic combination of energy-saving devices in front of and behind the propeller, and the energy-saving method is relatively single. In addition, the installation position of most energy-saving devices is fixed, that is, their position is fixed in the working state, which makes it impossible for the energy-saving devices to make adaptive adjustments according to the actual incoming flow of the ship at different speeds to make full use of the beneficial flow field morphology. On the other hand, the curvature of the appearance of the existing hydrodynamic energy-saving devices varies greatly and is irregular, and some devices have many structural parts and connectors and a relatively complex structure. The above factors will increase the difficulty of processing and manufacturing the entire energy-saving device, and there will also be certain difficulties in the actual installation and positioning. Third, the existing hydrodynamic energy-saving devices, the energy-saving devices in front of the propeller can only weaken the rotation of the wake by improving the inflow shape of the propeller disk, but cannot recover the energy dissipated by the wake. Some energy-saving devices behind the propeller can only recover limited wake energy due to their fixed position, and cannot reuse this energy to produce additional beneficial effects. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship, in which the energy-saving device can be adaptively adjusted according to the flow field morphology, and the utilization rate of the beneficial flow field is high; the energy-saving devices are organically combined to greatly improve the thrust efficiency; the energy-saving device has a simple structure, and the difficulty and cost of manufacturing and installation are low; the degree of wake rotation is low and the recovery and reuse rate of wake rotation energy is high.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions: A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship comprises a propeller, a pair of guide fins and a pre-swirl fin. The pre-swirl fin is arranged on the port side of the stern casting of the hull in front of the propeller, and the pair of guide fins are arranged in a mirror-symmetrical manner on the port and starboard sides of the hull in front of the pre-swirl fin and are rotatably connected to the hull.

[0005] Furthermore, the pre-spin fin includes three fins. Viewed clockwise from the port side to the starboard side of the ship, the three fins are respectively a first fin, a second fin and a third fin. The three fins are spaced apart along the outer circumference of the stern casting of the hull. The fins extend radially outward from the stern casting of the hull, and the width direction of the fins is parallel to the central axis direction of the propeller hub.

[0006] Furthermore, the lower end surface of the second fin is at the same height as the horizontal axis of the hub, and the first fin and the third fin are rotated and offset by a certain angle θ5 and δ respectively relative to the second fin. 5， The first fin deflection angle θ5 is in the range of 25° to 45°, and the third fin deflection angle δ5 is in the range of 35° to 65°.

[0007] Furthermore, the cross-sections of the first fin, the second fin and the third fin all adopt a low-resistance NACA airfoil design, and the first fin, the second fin and the third fin are all welded to the hull.

[0008] Furthermore, a pair of guide fins are respectively a port guide fin and a starboard guide fin, and the port guide fin and the starboard guide fin have the same structure, both including a guide fin rotating plate and a guide fin rotating shaft, a guide fin support seat is provided between the bottom of the guide fin rotating plate and the hull, the guide fin support seat is fixedly connected to the outer side wall of the hull, the top of the guide fin rotating shaft passes through the guide fin support seat and is rigidly connected to the guide fin rotating plate, the bottom of the guide fin rotating shaft is rigidly connected to the guide fin worm gear through the guide fin rotating seat, the guide fin worm gear is rotationally connected to the guide fin worm, and the guide fin motor is rigidly connected to the port guide fin worm through the guide fin connecting rod.

[0009] Furthermore, the cross-sections of the port side guide fin and the starboard side guide fin both adopt a high lift, low drag NACA 4-position airfoil design; the port side guide fin and the starboard side guide fin both adopt a swept angle design, and the swept angle β6 of the port side guide fin and the starboard side guide fin are both in the range of 8°~15°.

[0010] Furthermore, the installation positions of the port side guide fin and the starboard side guide fin are both located below the horizontal axis of the hub.

[0011] Furthermore, the system also includes a central controller and a signal processor. Fin mechanical sensors are provided on the fin turn plates of the port fin and the starboard fin. The fin mechanical sensors, the signal processor and the central controller are connected by cable control.

[0012] Furthermore, the system also includes a pair of rudder thrust fins, which are mirror-symmetrically arranged on the left and right sides of the rudder behind the propeller and are rotatably connected to the rudder.

[0013] Furthermore, the distance between the pre-spin fin and the propeller is smaller than the distance between the guide fin and the propeller.

[0014] Furthermore, a pair of the rudder thrust fins are respectively a port side rudder thrust fin and a starboard side rudder thrust fin, and the port side rudder thrust fin and the starboard side rudder thrust fin have the same structure, both including a rudder thrust fin rotating plate and a rudder thrust fin rotating shaft, the bottom of the rudder thrust fin rotating plate is connected to the hull via a rudder thrust fin supporting seat, the rudder thrust fin supporting seat is fixedly connected to the hull, the top of the rudder thrust fin rotating shaft passes through the rudder thrust fin supporting seat and is rigidly connected to the rudder thrust fin rotating plate, the bottom of the rudder thrust fin rotating shaft is rigidly connected to the rudder thrust fin worm gear via the rudder thrust fin rotating seat, the rudder thrust fin worm gear is rotationally connected to the rudder thrust fin worm, and the rudder thrust fin motor is rigidly connected to the rudder thrust fin worm via a rudder thrust fin connecting rod.

[0015] Furthermore, the installation heights of the port side rudder thrust fin and the starboard side rudder thrust fin are consistent with the height of the horizontal axis of the hub.

[0016] Furthermore, the cross-sectional shapes of the port side rudder thrust fin and the starboard side rudder thrust fin are NACA 4-position airfoils, and both are provided with a sweep angle β7, and the range of β7 is 9° to 13°.

[0017] Furthermore, the system also includes a central controller and a signal processor. Rudder thrust fin mechanical sensors are provided on the rudder thrust fin turn plates of the port rudder thrust fin and the starboard rudder thrust fin. The rudder thrust fin mechanical sensors, the signal processor and the central controller are connected by cable control.

[0018] The present invention is based on the basic theory of fluid mechanics and utilizes a computational fluid dynamics numerical simulation method to design guide fins, pre-swirl fins and rudder thrust fins. Fig.10The flow field information diagram in the numerical simulation results is given. FL is the lift generated by the guide fin and rudder thrust fin under the action of water flow, FD is the drag generated by the guide fin and rudder thrust fin under the action of water flow, and FT is the composite force of the lift and drag of the guide fin and rudder thrust fin in the forward direction of the ship, that is, the thrust generated by the guide fin and rudder thrust fin using the flow field, as shown in formula (1); α is the angle of attack formed between the front flow and the chord length of the guide fin and rudder thrust fin. This angle can be adaptively adjusted by rotating the fin plates of the guide fin and rudder thrust fin. As shown in formulas (2) to (4), after obtaining specific mechanical information, it can be converted into dimensionless parameters, such as lift coefficient CL, drag coefficient CD and thrust coefficient CT, which can make comparative analysis more convenient. The pre-swirl fin effectively utilizes the inflow after rectification by the front guide fin, rectifies this part of the flow field and forms a pre-swirl flow in the opposite direction of the propeller rotation, which inhibits the rotation of the propeller wake to a certain extent, reduces the energy dissipation caused by the wake rotation, increases the wake fraction, reduces the thrust reduction, and increases the hull efficiency and the final propulsion efficiency. Formulas (5) to (6) give the calculation formulas for the hull efficiency and propulsion efficiency, where t is the thrust reduction, w is the wake fraction, ηH is the hull efficiency, and ηD is the propulsion efficiency.

[0019] F_T=F_L sinα-F_D cosα (1) C_L=F_L / 0.5*ρ*V_A^2*S (2) C_D=F_D / 0.5*ρ*V_A^2*S (3) C_T=C_L sinα-C_D cosα (4) η_H=(1-t) / (1-w) (5) η_D=η_H*η_R*η_o (6) Compared with the prior art, the present invention has the following beneficial effects: 1. The guide fin, pre-swirl fin and rudder thrust fin are used in an organic combination. The guide fin can use the incoming flow at the stern of the hull to generate thrust, and can also rectify the incoming flow and guide this part of the flow field to the surface of the pre-swirl fin; the three fins of the pre-swirl fin can turn the flow field in front, and the direction of the pre-swirl flow after the steering is opposite to the direction of rotation of the propeller, that is, the pre-swirl fin can form a pre-swirl flow after rectifying this part of the flow field, and the pre-swirl flow is opposite to the direction of rotation of the propeller, thereby suppressing the rotation of the propeller wake and reducing the energy loss caused by the wake rotation; the rudder thrust fin can use the rotating wake that the pre-swirl fin cannot suppress, recover and reuse this part of the energy, thereby generating beneficial thrust, and further improving the propulsion efficiency.

[0020] 2. The guide fin adopts a rotating fin design with a mechanical sensor installed. When the front flow acts on the surface of the guide fin, the generated mechanical signal will be transmitted to the signal processor in real time for conversion and then transmitted to the central controller. The central controller will send instructions to the motor inside the corresponding worm gear device, thereby realizing adaptive rotation adjustment of the guide fin to make full use of the flow field shape and generate beneficial thrust.

[0021] 3. The rudder thrust fin also adopts a rotating fin design with a mechanical sensor installed. When the forward flow acts on the surface of the rudder thrust fin, the generated mechanical signal will be transmitted to the signal processor in real time for conversion and then transmitted to the central controller. The central controller will send instructions to the motor inside the corresponding worm gear device, thereby realizing adaptive rotation adjustment of the rudder thrust fin to fully recover and utilize the energy lost in the rotation of the wake behind the spiral to generate beneficial thrust.

[0022] 4. The cross-sections of the guide fins and rudder thrust fins all adopt the high-lift, low-drag NACA 4-position airfoil to generate higher beneficial thrust under the same incoming flow pattern; the pre-swirl fins adopt the low-drag NACA airfoil design to ensure that the guide fins will not generate large resistance while generating beneficial pre-swirl flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an axonometric view of a combined hydrodynamic energy-saving system with adaptive adjustment for the stern of a ship according to the present invention.

[0024] Figure 2 The present invention is a port side view of a combined hydrodynamic energy-saving system for adaptively adjusting the stern of a ship.

[0025] Figure 3 The present invention is a starboard side view of a combined hydrodynamic energy-saving system for adaptively adjusting the stern of a ship.

[0026] Figure 4 The present invention is a schematic diagram of the composition of the guide fin rotating mechanism in a combined hydrodynamic energy-saving system for adaptive adjustment of the stern of a ship.

[0027] Figure 5 The present invention is a schematic diagram of the composition of a rudder thrust fin rotating mechanism in a combined hydrodynamic energy-saving and efficiency-enhancing system for a ship's stern.

[0028] Figure 6 It is a main scale schematic diagram of a guide fin in a combined hydrodynamic energy-saving and efficiency-enhancing system for a ship's stern according to the present invention.

[0029] Figure 7 The main scale schematic diagram of the rudder thrust fin in the combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to the present invention.

[0030] Figure 8 The present invention is a schematic diagram of the structural composition and installation positioning of the pre-rotating fin in a combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship.

[0031] Fig. 9 The present invention is a schematic diagram of the working logic of an automatic control module of a combined hydrodynamic energy-saving and efficiency-enhancing system for a ship's stern.

[0032] Fig.10 It is a schematic diagram of the flow field simulation results involved in a combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to the present invention.

[0033] Among them, 1. hull; 2. rudder; 3. hub; 4. propeller; 6. port guide fin; 7. port rudder thrust fin; 8. starboard guide fin; 9. starboard rudder thrust fin; 501. first fin; 502. second fin; 503. third fin; 601. guide fin rotating plate; 602. guide fin support seat; 603. guide fin rotating shaft; 604. guide fin rotating seat; 605. guide fin worm gear; 606. guide fin motor; 607. guide fin connecting rod; 608. guide fin worm; 701. rudder thrust fin rotating plate; 702. rudder thrust fin support seat; 703. rudder thrust fin rotating shaft; 704. rudder thrust fin rotating seat; 705. rudder thrust fin worm gear; 706. rudder thrust fin motor; 707. rudder thrust fin connecting rod; 708. rudder thrust fin worm. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Fig. 9 and Fig.10As shown, the automatic control logic of a combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship of the present invention, as well as the working principle of the organic combination of guide fins, pre-swirl fins and rudder thrust fins. When the ship is in a sailing state, the flow field at the stern of the ship will flow along the surface of the hull 1 from front to back, and the first energy-saving devices to be contacted are the port guide fin 6 and the starboard guide fin 8. The port guide fin and the starboard guide fin have similar structures, and the port guide fin is taken as an example for explanation here. When the water flow impacts the surface of the port guide fin 6, the port guide fin rotating plate 601 with a mechanical sensor in the port guide fin 6 can transmit the mechanical information of the surface to the signal processor in real time, and transmit it to the central controller in the ship's driving room after processing, and the central controller sends an operation instruction to the corresponding port guide fin motor 606. Driven by the port guide fin motor 606, the port guide fin worm 608 rotates, thereby driving the rotation of the port guide fin worm wheel 605, and finally driving the port guide fin rotating plate 601 to rotate, so that the angle of attack α between the chord length direction of the port guide fin 6 and the water flow direction can be adaptively adjusted according to the incoming flow conditions at different speeds, so as to make full use of the flow field to generate beneficial thrust. The front incoming flow will flow directly to the pre-swirl fin after being rectified by the guide fin. The first fin plate 501, the second fin plate 502 and the third fin plate 503 of the pre-swirl fin further rectify the flow field after the rectification of this part of the guide fin, so that it produces a pre-swirl flow in the opposite direction of the rotation of the propeller 4. After this part of the pre-swirl flow flows to the propeller 4, it can effectively suppress the rotation of the propeller 4 wake, reducing the energy loss caused by the rotation of this part of the wake. When a small amount of rotating wake continues to flow toward the rudder 2, it will act on the port rudder thrust fin 7 and the starboard rudder thrust fin 9. The port rudder thrust fin 7 and the starboard rudder thrust fin 9 have similar structures. Here, the port rudder thrust fin 7 is used as an example for explanation. When the rotating wake behind the propeller 4 impacts the surface of the port rudder thrust fin 7, the port rudder thrust fin rotating plate 701 with a mechanical sensor in the port rudder thrust fin 7 can transmit the mechanical information of the surface to the signal processor in real time, and transmit it to the central controller in the ship's driving room after processing, and the central controller sends an operation instruction to the corresponding port rudder thrust fin motor 706. Driven by the port rudder thrust fin motor 706, the port rudder thrust fin worm 708 rotates, thereby driving the rotation of the port rudder thrust fin worm wheel 705, and finally driving the port rudder thrust fin rotating plate 701 to rotate, so that the attack angle α between the chord length direction of the port rudder thrust fin 7 and the water flow direction can be adaptively adjusted according to the incoming flow conditions at different speeds, so as to make full use of the flow field to generate beneficial thrust. In general, the combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship involved in the present invention can not only make full use of the beneficial flow field to generate beneficial thrust and reduce the energy loss caused by the wake rotation of the propeller 4, but also recover the lost energy and use this part of energy to convert it into beneficial thrust, effectively improving the thrust efficiency, and the energy-saving effect is remarkable.

[0036] like Figures 1 to 3 As shown, a combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship includes a propeller 4, a pair of guide fins and a pre-swirl fin. The pre-swirl fin is arranged on the port side of the stern casting of the hull 1 in front of the propeller 4, and the pair of guide fins are mirror-symmetrically arranged on the port and starboard sides of the hull 1 in front of the pre-swirl fin, and are rotatably connected to the hull 1.

[0037] It can be understood that the guide fin can utilize the incoming flow at the stern of the hull 1 to generate thrust, and can also rectify the incoming flow and guide this part of the flow field to the surface of the pre-swirl fin; after the pre-swirl fin rectifyes this part of the flow field, a pre-swirl flow can be formed, and the pre-swirl flow is opposite to the rotation direction of the propeller 4, thereby suppressing the rotation of the propeller 4 wake, and reducing the energy loss caused by the wake rotation.

[0038] In some embodiments, Figure 2 and Figure 8 As shown, the pre-spin fin includes three fins. When viewed clockwise from the port side to the starboard side of the ship, the three fins are respectively a first fin 501, a second fin 502 and a third fin 503. The three fins are arranged circumferentially at intervals along the outer circle of the stern casting of the hull 1. The fins extend radially outward from the stern casting of the hull 1, and the width direction of the fins is parallel to the central axis direction of the propeller hub; the lower end surface of the second fin 502 is consistent with the height of the horizontal axis of the propeller hub 3, and the first fin 501 and the third fin 503 are rotated and offset by a certain angle θ5 and δ5 respectively relative to the second fin 502. 5， Among them, the deflection angle θ5 of the first fin 501 ranges from 25° to 45°, and the deflection angle δ5 of the third fin 503 ranges from 35° to 65°. Such a design can ensure that the pre-swirl fin fully utilizes the flow field morphology after the front guide fin is rectified to generate a pre-swirl flow opposite to the rotation direction of the propeller 44, thereby effectively suppressing the wake rotation of the propeller 4, that is, it can effectively reduce the energy dissipation caused by the wake rotation, increase the wake fraction, and reduce the thrust reduction, effectively improving the propulsion efficiency.

[0039] In some embodiments, the cross-sections of the first fin 501, the second fin 502 and the third fin 503 all adopt a low-resistance NACA airfoil design, and the first fin 501, the second fin 502 and the third fin 503 are all welded to the hull 1. Such a configuration can ensure that the pre-spin fins will not generate large resistance while generating beneficial pre-spin.

[0040] In some embodiments, Figure 4As shown, a pair of guide fins are respectively a port guide fin 6 and a starboard guide fin 8. The port guide fin 6 and the starboard guide fin 8 have the same structure, both including a guide fin rotating plate 601 and a guide fin rotating shaft 603. A guide fin support seat 602 is provided between the bottom of the guide fin rotating plate 601 and the hull 1. The guide fin support seat 602 is fixedly connected to the outer wall of the hull 1. The top of the guide fin rotating shaft 603 passes through the guide fin rotating shaft 603 and is rigidly connected to the guide fin rotating plate 601. The bottom of the guide fin rotating shaft 603 is rigidly connected to the guide fin worm gear 605 through the guide fin rotating seat 604. The guide fin worm gear 605 is rotationally connected to the guide fin worm 608. The guide fin motor 606 is rigidly connected to the worm of the port guide fin 6 through the guide fin connecting rod 607. With such arrangement, the motor of the port side guide fin 6 can drive the worm gear of the port side guide fin 6 to rotate by controlling the worm gear of the port side guide fin 6 to rotate, and finally act on the port side guide fin rotating plate 601 to achieve the function of adjusting the rotation of the guide fin.

[0041] In some embodiments, Figure 6 As shown, the cross-sections of the port guide fin 6 and the starboard guide fin 8 both adopt the NACA 4-position airfoil design with high lift and low drag; the port guide fin 6 and the starboard guide fin 8 both adopt the design of swept angle, and the range of the swept angle β6 of the port guide fin 6 and the starboard guide fin 8 is 8°~15°. Such a design can ensure that the guide fin has a higher lift coefficient and a lower drag coefficient, thereby generating a higher effective thrust. The value of the swept angle β6 can be 8°, 10°, 12°, 14° or 15°.

[0042] In some embodiments, the installation positions of the port guide fin 6 and the starboard guide fin 8 are both located below the horizontal axis of the hub 3. Such an arrangement can better guide the flow field in front to the pre-swirl fin area.

[0043] In some embodiments, Fig. 9 As shown, the system also includes a central controller and a signal processor, and guide fin mechanical sensors are provided on the guide fin rotating plates 601 of the port guide fin 6 and the starboard guide fin 8, and the guide fin mechanical sensors, the signal processor and the central controller are connected by cable control. It can be understood that when the front water flow impacts the surface of the guide fin, the generated mechanical signal will be transmitted to the signal processor in real time for conversion and then transmitted to the central controller, and the central controller will send instructions to the motor inside the worm gear device, thereby realizing the automatic rotation of the guide fin, so as to make full use of the front flow field shape to generate additional thrust.

[0044] In this embodiment, if Figure 1 and Figure 3As shown, the system further includes a pair of rudder thrust fins, which are mirror-symmetrically arranged on the left and right sides of the rudder behind the propeller 4 and are rotatably connected to the rudder. In this arrangement, the rudder thrust fins can utilize the rotating wake that the pre-rotation fins cannot suppress, recover and reuse this part of energy, and then generate beneficial thrust, further improving the propulsion efficiency.

[0045] Furthermore, the distance between the pre-swirl fin and the propeller 4 is smaller than the distance between the guide fin and the propeller 4. With such an arrangement, the front incoming flow can be pre-swirled and directly act on the propeller 4 disk.

[0046] Specifically, Figure 5 As shown, a pair of rudder thrust fins are respectively a port rudder thrust fin 7 and a starboard rudder thrust fin 9, and the port rudder thrust fin 7 and the starboard rudder thrust fin 9 have the same structure, both including a rudder thrust fin rotating plate 701 and a rudder thrust fin rotating shaft 703, the bottom of the rudder thrust fin rotating plate 701 is connected to the hull 1 through a rudder thrust fin supporting seat 702, the rudder thrust fin supporting seat 702 is fixedly connected to the hull 1, the top of the rudder thrust fin rotating shaft 703 passes through the rudder thrust fin supporting seat 702 and is rigidly connected to the rudder thrust fin rotating plate 701, the bottom of the rudder thrust fin rotating shaft 703 is rigidly connected to the rudder thrust fin worm gear 705 through the rudder thrust fin supporting seat 704, the rudder thrust fin worm gear 705 is rotationally connected to the rudder thrust fin worm 708, and the rudder thrust fin motor 706 is rigidly connected to the rudder thrust fin worm 708 through the rudder thrust fin connecting rod 707. With such arrangement, the rudder thrust fin motor 706 can drive the rudder thrust fin worm gear 705 to rotate by controlling the rudder thrust fin worm gear 708 to rotate, and finally act on the rudder thrust fin rotating plate 701 to achieve the function of adjusting the rotation of the rudder thrust fin.

[0047] Further, such as Figure 2 and Figure 3 As shown, the installation height of the port rudder thrust fin 7 and the starboard rudder thrust fin 9 is consistent with the height of the horizontal axis of the hub 3. Such an arrangement can ensure that the rotating wake behind the propeller 4 can directly act on the rudder thrust fin.

[0048] Further, such as Figure 7 As shown, the cross-sectional shape of the port rudder thrust fin 7 and the starboard rudder thrust fin 9 is a NACA 4-position airfoil, and both are provided with a sweep angle β7, and the range of β7 is 9° to 13°. Such a design can ensure that the rudder thrust fin has a higher lift coefficient and a lower drag coefficient, thereby generating a higher effective thrust.

[0049] Further, such as Figure 5As shown, the system also includes a central controller and a signal processor, and a rudder thrust fin mechanical sensor is provided on the rudder thrust fin rotating plate 701 of the port rudder thrust fin 7 and the starboard rudder thrust fin 9, and the rudder thrust fin mechanical sensor, the signal processor and the central controller are connected by cable control. It can be understood that when the front water flow impacts the surface of the rudder thrust fin, the generated mechanical signal will be transmitted to the signal processor in real time for conversion and then transmitted to the central controller, and the central controller will send instructions to the motor inside the worm gear device, thereby realizing the automatic rotation of the rudder thrust fin, so as to fully recover the energy lost by the wake rotation and generate additional thrust.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship, characterized in that: The invention comprises a propeller, a pair of guide fins and a pre-swirl fin. The pre-swirl fin is arranged on the port side of the stern casting of the hull in front of the propeller. The pair of guide fins are arranged on the port and starboard sides of the hull in front of the pre-swirl fin in a mirror-symmetrical manner and are rotatably connected to the hull.

2. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 1, characterized in that: The pre-spin fin includes three fins. Viewed clockwise from the port side to the starboard side of the ship, the three fins are respectively the first fin, the second fin and the third fin. The three fins are spaced apart along the outer circumference of the stern casting of the hull. The fins extend radially outward from the stern casting of the hull, and the width direction of the fins is parallel to the central axis direction of the propeller hub.

3. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 2, characterized in that: The lower end surface of the second fin is at the same height as the horizontal axis of the hub, and the first fin and the third fin are rotated and offset by a certain angle θ5 and δ respectively relative to the second fin. 5， Among them, the deflection angle θ5 of the first fin is in the range of 25°~45°, and the deflection angle δ5 of the third fin is in the range of 35°~65°; the cross-sections of the first fin, the second fin and the third fin all adopt a low-resistance NACA airfoil design, and the first fin, the second fin and the third fin are all welded to the hull.

4. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to any one of claims 1 to 3, characterized in that: The pair of guide fins are respectively a port side guide fin and a starboard side guide fin. The port side guide fin and the starboard side guide fin have the same structure and both include a guide fin rotating plate and a guide fin rotating shaft. A guide fin support seat is provided between the bottom of the guide fin rotating plate and the hull. The guide fin support seat is fixedly connected to the outer side wall of the hull. The top of the guide fin rotating shaft passes through the guide fin support seat and is rigidly connected to the guide fin rotating plate. The bottom of the guide fin rotating shaft is rigidly connected to the guide fin worm gear through the guide fin rotating seat. The guide fin worm gear is rotationally connected to the guide fin worm gear. The guide fin motor is rigidly connected to the port side guide fin worm gear through the guide fin connecting rod.

5. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 4, characterized in that: The cross-sections of the port side guide fin and the starboard side guide fin both adopt a NACA 4-position airfoil design with high lift and low resistance; the port side guide fin and the starboard side guide fin both adopt a swept angle design, and the swept angle β6 of the port side guide fin and the starboard side guide fin is in the range of 8° to 15°; the installation positions of the port side guide fin and the starboard side guide fin are both located below the horizontal axis of the hub.

6. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 5, characterized in that: The system also includes a central controller and a signal processor. Fin mechanical sensors are provided on the fin turn plates of the port fin and the starboard fin. The fin mechanical sensors, the signal processor and the central controller are connected through cable control.

7. A ship stern combined hydrodynamic energy saving and efficiency enhancement system according to any one of claims 1, 2, 3, 5 or 6, characterized in that: The system also includes a pair of rudder thrust fins, which are arranged on the left and right sides of the rudder behind the propeller in a mirror-symmetrical manner and are rotatably connected to the rudder.

8. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 7, characterized in that: A pair of rudder thrust fins are respectively a port rudder thrust fin and a starboard rudder thrust fin. The port rudder thrust fin and the starboard rudder thrust fin have the same structure and both include a rudder thrust fin rotating plate and a rudder thrust fin rotating shaft. The bottom of the rudder thrust fin rotating plate is connected to the hull through a rudder thrust fin supporting seat, the rudder thrust fin supporting seat is fixedly connected to the hull, the top of the rudder thrust fin rotating shaft passes through the rudder thrust fin supporting seat and is rigidly connected to the rudder thrust fin rotating plate, the bottom of the rudder thrust fin rotating shaft is rigidly connected to the rudder thrust fin worm gear through the rudder thrust fin rotating seat, the rudder thrust fin worm gear is rotationally connected to the rudder thrust fin worm, and the rudder thrust fin motor is rigidly connected to the rudder thrust fin worm through a rudder thrust fin connecting rod.

9. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 8, characterized in that: The installation heights of the port side rudder thrust fin and the starboard side rudder thrust fin are consistent with the height of the horizontal axis of the hub; the cross-sectional shapes of the port side rudder thrust fin and the starboard side rudder thrust fin are NACA 4-position airfoils, and both are provided with a sweep angle β7, and the range of β7 is 9°~13°.

10. A combined hydrodynamic energy-saving and efficiency-enhancing system for the stern of a ship according to claim 9, characterized in that: The system also includes a central controller and a signal processor. Rudder thrust fin mechanical sensors are provided on the rudder thrust fin rotating plates of the port rudder thrust fin and the starboard rudder thrust fin. The rudder thrust fin mechanical sensors, the signal processor and the central controller are connected through cable control.

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