Energy-saving hydrofoil for thin stern ships

Abstract

The present invention discloses an energy-saving hydrofoil for a thin stern ship, comprising a plurality of spanwise hydrofoils and a circumferential wing; the spanwise hydrofoil is in a trapezoidal shape after being unfolded, and its root is connected to the stern of the hull, and the section connected with the hull gradually decreases toward the tip along the spanwise direction; the spanwise hydrofoil section is in the form of a wing section, and is circumferentially distributed on the stern structure of the hull in front of the propeller; the circumferential wing outlet intersects with the spanwise hydrofoil section. The energy-saving hydrofoil of the present invention is a hull auxiliary structure, which can better improve the flow field at the stern of the thin hull of the ship, improve the cavitation performance of the propeller, reduce the vibration of the propeller, reduce noise pollution, and achieve energy-saving and emission reduction effects.

Description

Technical Field

[0001] The invention relates to a combined energy-saving hydrofoil for a ship, in particular to an energy-saving hydrofoil for a slim stern ship. Background Art

[0002] Since the beginning of the 21st century, people have paid more attention to energy conservation and environmental protection. Ship pollution has entered the public's field of vision, and it is imperative to reduce ship energy consumption. The International Maritime Organization has put forward mandatory quantitative requirements for ship energy conservation and emission reduction, requiring that the EEDI (Ship Energy Efficiency Index) of new ships be reduced by 30% by 2025. This is a great test for ship design. How to reduce ship energy consumption has become the focus of attention. All sectors of the shipping industry have taken various measures to this end, and ship emission reduction technology has developed rapidly. As a research focus, hydrodynamic energy-saving technology can effectively achieve energy-saving and emission reduction effects. The current front energy-saving devices include wake compensation ducts, front pre-rotation guide wheels, Mewis Ducts, etc., but these energy-saving devices can only be used on specific ship types, and the overall shape of the energy-saving devices is large. Problems such as cannot be well applied on ships with small wake at the stern of the hull.

[0003] The ship duct and the ship disclosed in CN 202368781 U are composed of an airfoil plate-shaped body and a flat plate structure. The structure is too simple and has poor structural vibration performance. It can only be used for specific ship types, has poor energy-saving effect, and cannot be effectively promoted.

[0004] CN 103342162A discloses a front semi-guide wheel, which is composed of a front semi-duct and a plurality of front guide blades. The tube wall of the front semi-duct is partially notched in the axial direction. One end of the guide blade is circumferentially arranged on the inner wall of the front semi-duct, and the other end is connected to the stern of the hull. This structure can produce a relatively good energy-saving effect on fat ships and ships with large stern wake, but cannot improve the propeller plane wake on ships with small stern wake (such as thin stern ships), so it cannot produce a relatively good energy-saving effect.

[0005] CN 103332280A discloses a Guangguang type front guide wheel, which adopts a front guide pipe and a plurality of front guide blades, wherein the front guide blades are dispersedly arranged on the inner wall of the front guide pipe, and the front guide blades at the inner wall extend to the outside of the front guide pipe. The structure has a large guide pipe and a large wet surface area, which generates a large resistance when the ship is sailing at high speed, and cannot achieve the expected energy saving effect on high-speed ships. Summary of the invention

[0006] The purpose of the present invention is to fill the deficiencies in the prior art and to provide an energy-saving device for use on high-speed ships with a small wake at the stern of the hull, which can improve the propeller efficiency of the ship, reduce energy loss, and achieve the effect of energy saving and emission reduction.

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

[0008] An energy-saving hydrofoil for a slim stern ship comprises a plurality of spanwise hydrofoils and a circumferential wing; the spanwise hydrofoil is trapezoidal when unfolded, the root of the spanwise hydrofoil is connected to the stern of the hull, and the section connected to the hull gradually decreases toward the tip along the spanwise direction; the spanwise hydrofoil section is in the form of an wing section and is circumferentially distributed on the stern structure of the hull in front of the propeller; the circumferential wing outlet intersects with the spanwise hydrofoil section.

[0009] Preferably, the circumferential wing is closed.

[0010] Preferably, the lower end of the circumferential wing is open.

[0011] Preferably, the span of the spanwise hydrofoil is 0.85 to 1.1 times the propeller radius, and the cross-sectional chord length of the spanwise hydrofoil at the intersection with the circumferential wing is 0.95 to 1.5 times the cross-sectional chord length of the circumferential wing.

[0012] Preferably, there are 1 to 3 hydrofoils on the left and starboard sides, and the number on the port side is not less than that on the starboard side.

[0013] Preferably, the inlet diameter of the annular wing is 0.35 to 0.55 times the diameter of the propeller, and the outlet diameter is 0.3 to 0.5 times the diameter of the propeller.

[0014] Preferably, the longitudinal inclination angle of the circumferential wing is -3° to 5°.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention relates to a new type of energy-saving hydrofoil for a thin stern ship, which is installed in front of a propeller and consists of a spanwise hydrofoil and a circumferential wing. The spanwise hydrofoil is unevenly arranged at the stern of the hull, and the circumferential wing is interspersed on the spanwise hydrofoil. The device can better solve the problem of small wake flow of the hull and poor energy-saving effect of the same type, can greatly improve the pre-swirl of the water flow in front of the propeller, reduce the energy loss at the tail of the propeller, and obtain a considerable energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of an energy-saving hydrofoil according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of an energy-saving hydrofoil installed at the stern of a ship according to an embodiment of the present invention;

[0019] Figure 3 This is a starboard side view of an energy-saving hydrofoil according to an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of the circumferential wing shape of an energy-saving hydrofoil according to another embodiment of the present invention;

[0021] Figure 5 A side view of the circumferential wing shape of an energy-saving hydrofoil according to another embodiment of the present invention.

[0022] In the figure, 100 is the circumferential wing; 101 is the centerline of the propeller shaft; 102 is the centerline of the circumferential wing; 201 to 205 are the spanwise hydrofoils; 300 is the stern of the hull. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear, various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Please refer to Figures 1 to 5 , an energy-saving hydrofoil for a thin stern ship, comprising a plurality of spanwise hydrofoils 201-205 and a circumferential wing 100; the spanwise hydrofoils 201-205 are trapezoidal after being unfolded, and their roots are connected to the stern 300 of the hull, and the section connected to the hull gradually decreases toward the tip along the span direction; the sections of the spanwise hydrofoils 201-205 are in the form of wing sections, and are circumferentially distributed on the stern 300 structure of the hull in front of the propeller, and the spanwise hydrofoils 201-205 structure is connected to the circumferential wing 100; the outlet of the circumferential wing 100 (the inlet direction of the circumferential wing 100 is the bow direction, and the outlet direction of the circumferential wing 100 is the stern direction, such as Figure 3 As shown) intersects with the spanwise hydrofoil 201-205 sections.

[0025] The span length of the spanwise hydrofoils 201-205 is 0.85-1.1 times the propeller radius. This length of hydrofoil can improve the pre-swirl flow at the propeller tip, improve the propeller tip cavitation, and reduce propeller vibration. The cross-sectional chord length of the spanwise hydrofoils 201-205 at the intersection with the circumferential wing 100 is 0.95-1.5 times the cross-sectional chord length of the circumferential wing 100.

[0026] The spanwise hydrofoils 201-205 have 1-3 pieces on the left and starboard sides, and the number on the port side is not less than that on the starboard side. For example, the spanwise hydrofoils 201-205 have 2-3 pieces on the port side and 1-2 pieces on the starboard side. The spanwise hydrofoils 201-205 are determined according to the flow field conditions of the stern 300 of the hull.

[0027] The inlet diameter of the circumferential wing 100 is 0.35 to 0.55 times the diameter of the propeller, and the outlet diameter is 0.3 to 0.5 times the diameter of the propeller. The circumferential wing 100 has a structural reinforcement effect, connecting the spanwise hydrofoils 201 to 205 to improve the overall vibration performance of the structure. At the same time, the circumferential wing 100 can reduce the effect of the spanwise hydrofoils 201 to 205 on the hull.

[0028] The longitudinal inclination angle of the circumferential wing 100 is -3° to 5°.

[0029] like Figure 1 As shown, an energy-saving hydrofoil comprises an annular wing 100 and spanwise hydrofoils 201 to 205, wherein the outlet of the annular wing 100 intersects with the spanwise hydrofoils 201 to 205. The radius of the annular wing is about half of the radius of the blade tip of the spanwise hydrofoil.

[0030] like Figure 2 As shown, the energy-saving hydrofoil is installed at the stern of the hull 300, and one end of the spanwise hydrofoil 201-205 is connected to the stern of the hull. The center of the spanwise hydrofoil 201-205 is the propeller shaft centerline 101, and the circumferential wing center 102 is 100mm below the propeller shaft centerline 101.

[0031] like Figure 3 As shown, the chord length of the intersection of the spanwise hydrofoils 203-205 and the circumferential wing 100 is 1.2 times the chord length of the circumferential wing 100. The spanwise hydrofoils 203-205 can generate a larger pre-swirl.

[0032] like Figure 4 and Figure 5 Another embodiment of the present invention is shown, in which the annular wing 100 has an opening near the lower end of the hull. Mainly because the tail of the hull is fatter near the lower end, if the annular wing 100 is a full circle, it will intersect with the hull, and the intersection will shrink sharply to produce unfavorable vortices, so this section is cut off to make the annular wing 100 open and not intersecting with the hull.

[0033] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An energy-saving hydrofoil for a thin stern ship, characterized in that: It comprises a plurality of spanwise hydrofoils and an annular wing; the spanwise hydrofoil is in a trapezoidal shape after being unfolded, the root of which is connected to the stern of the hull, and the section connected to the hull gradually decreases toward the tip along the spanwise direction; the spanwise hydrofoil section is in the form of an airfoil section, and is circumferentially distributed on the stern structure of the hull in front of the propeller; the annular wing outlet intersects with the spanwise hydrofoil section; and the center of the annular wing is located below the centerline of the propeller shaft of the propeller; The span length of the spanwise hydrofoil is 0.85 to 1.1 times the propeller radius, and the cross-sectional chord length of the spanwise hydrofoil at the intersection with the circumferential wing is 0.95 to 1.5 times the cross-sectional chord length of the circumferential wing; The inlet diameter of the annular wing is 0.35 to 0.55 times the diameter of the propeller, and the outlet diameter is 0.3 to 0.5 times the diameter of the propeller.

2. The energy-saving hydrofoil for a thin stern ship according to claim 1, characterized in that: The circumferential wing is closed.

3. The energy-saving hydrofoil for a thin stern ship according to claim 1, characterized in that: The lower end of the circumferential wing is open.

4. The energy-saving hydrofoil for a thin stern ship according to claim 1, characterized in that: The left and starboard sides of the spanwise hydrofoil each have 1 to 3 pieces, and the number on the port side is not less than that on the starboard side.

5. The energy-saving hydrofoil for a thin stern ship according to claim 1, characterized in that: The longitudinal inclination angle of the circumferential wing is -3° to 5°.

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