Energy-saving semi-guide wheel in front of propeller

Abstract

The present invention discloses a propeller-front energy-saving semi-guide wheel, comprising a fan-shaped duct installed on the port side of the stern near the tail shaft outlet, and blades arranged horizontally in the circumferential direction of the duct; the two ends of the blades are respectively fixed to the stern and the inner wall of the fan-shaped duct; wherein the fan-shaped duct is symmetrically arranged about the horizontal plane passing through the center of the propeller shaft, and its circumferential angle range is 90-130°; the duct is a contractile duct, the inlet diameter is larger than its outlet diameter, and the duct contraction angle is not greater than 6°; the duct sections of the upper and lower halves of the fan-shaped duct are airfoil-shaped sections, and the back and blade surfaces of the blades are arranged in opposite directions; the longitudinal installation angle of the blades is not greater than 9°. Aiming at the characteristics of the accompanying flow field of the right-hand propeller, the propeller-front energy-saving semi-guide wheel of the present invention can generate a favorable propeller pre-swirl inflow on the port side through the special design of the duct and the blade section, increase the inflow attack angle of the propeller blade section, improve the propulsion efficiency while minimizing the increase in ship resistance, and achieve significant energy-saving effects.

Description

Technical Field

[0001] The invention relates to a novel ship hydrodynamic energy-saving device, in particular to an energy-saving pre-rotating semi-guide wheel in front of a ship's propeller used for large medium and low-speed transport ships. 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) index of new ships be reduced by 30% by 2025, which is a great test for ship design. Under the increasingly severe environmental pressure, ship energy conservation and emission reduction have attracted much attention from the shipbuilding and shipping industries. How to reduce ship energy consumption has become the focus of attention. All sectors of the shipping industry have taken various measures. New ships have taken energy-saving measures to reduce fuel consumption, and ship emission reduction technology has developed rapidly. From the perspective of ship propulsion, energy-saving devices can be installed at the rear of the hull to improve propulsion efficiency, thereby achieving the purpose of energy saving. As the focus of research, 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 rear of the hull. With the optimization of ship types and the improvement of propeller design technology, traditional propeller-front energy-saving devices often fail to achieve ideal energy-saving effects.

[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 present invention aims to provide an energy-saving semi-guide wheel in front of a propeller: it comprises a fan-shaped duct installed on the port side of the stern of a hull near the outlet of a tail shaft, and blades arranged circumferentially in the duct; the fan-shaped duct is symmetrically arranged about a horizontal plane passing through the center of the propeller shaft, and the two ends of the blades are respectively fixed to the stern and the inner wall of the fan-shaped duct.

[0007] The fan-shaped duct is integrated, and its circumferential angle range is 90-130°.

[0008] The outlet diameter of the fan-shaped duct is 1.0 of the propeller diameter D, and the inlet diameter of the fan-shaped duct is larger than its outlet diameter.

[0009] The contraction angle of the fan-shaped duct is not greater than 6°.

[0010] The fan-shaped duct comprises an upper connecting section, an upper half, a middle transition section, a lower half and a lower connecting section which are connected in sequence.

[0011] The upper and lower duct sections are airfoil-shaped sections.

[0012] The blade backs and blade faces of the upper and lower duct sections are arranged in opposite directions, the blade backs of the upper duct section face outwards, and the blade backs of the lower duct section face inwards.

[0013] The cross section of the middle transition section duct is a symmetrical airfoil cross section.

[0014] The blades are arranged horizontally in the circumferential direction, and the longitudinal installation angle of the blades is not greater than 9°.

[0015] The back of the leaf in the cross section faces upward.

[0016] The present invention relates to an energy-saving semi-guide wheel in front of a propeller, which is installed on the port side of the stern and close to the outlet of the tail shaft. Based on the characteristics of the wake field of a right-hand propeller, the special design of a duct and a blade section can improve the wake field of the left half plane of the propeller, increase the inflow attack angle of the propeller blade section, and improve the propulsion efficiency while minimizing the increase in ship resistance, thereby achieving the purpose of energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the energy-saving semi-guide wheel structure in front of the propeller of the present invention;

[0018] Figure 2 This is a schematic diagram of the cross-section arrangement of the energy-saving semi-guide wheel blade in front of the propeller of the present invention;

[0019] Figure 3 It is a schematic diagram of the blade surface and blade back orientation of the blade section of the energy-saving semi-guide wheel blade in front of the propeller of the present invention;

[0020] Figure 4 This is a schematic diagram of the installation of the energy-saving semi-guide wheel in front of the propeller of the present invention;

[0021] Figure 5 It is a schematic diagram of the contraction of the fan-shaped duct of the energy-saving semi-guide wheel in front of the propeller of the present invention. DETAILED DESCRIPTION

[0022] The present invention aims to provide a propulsion energy-saving device for improving propeller inflow, improving propeller propulsion efficiency, and reducing ship energy consumption. The device is installed on the port side of the stern of the ship, near the front of the tail shaft outlet, and is called a propeller-front energy-saving semi-guide wheel. The propellers of large medium and low-speed transport ships usually adopt a right-hand propeller design, and the wake field at the stern is in the same direction as the propeller rotation on the port side, and in the opposite direction of the propeller rotation on the right side. There is more room for improvement in the wake field on the port side, so the energy-saving device can produce a more obvious effect of improving the wake on the port side of the stern, but has a limited effect on the starboard side, and may even have a negative impact.

[0023] like Figure 1 As shown, the energy-saving semi-guide wheel in front of the propeller of the present invention is composed of an integrated fan-shaped duct 100 and a stator blade 200. The fan-shaped duct 100 can be divided into five welded parts according to the circumferential position, namely, the duct upper connecting section 101, the duct upper half 102, the duct middle transition section 103, the duct lower half 104 and the duct lower connecting section 105. Based on the inflow characteristics of the right-hand propeller blade section on the port side, the design of the upper half duct and the lower half duct section can more effectively improve the axial inflow, the design of the upper connecting section and the lower connecting section duct section can generate a tangential inflow opposite to the propeller rotation direction, and the design of the blade section with the back facing upward is also for better generating pre-swirl inflow, the upper connecting section duct is set at a certain angle away from the upper part to avoid the peak area of ​​the wake flow; the lower connecting section duct is set at a certain angle away from the lower part to reduce the adverse interference with the hull. In general, through the special design of the duct and blade profile, the wake field on the left half plane of the propeller can be improved, the inflow angle of the propeller blade profile can be increased, and the propulsion efficiency can be improved while minimizing the increase in ship resistance, thereby achieving energy saving.

[0024] like Figure 4As shown, the fan-shaped duct 100 is arranged on the port side of the stern, connected to the surface of the hull 300 through both ends, and its horizontal centerline passes through the center of the propeller shaft, and is symmetrically arranged up and down about the horizontal plane 400 passing through the center of the propeller shaft. The circumferential angle range of the fan-shaped duct 100 is 90-130°, and the longitudinal installation angle of the duct is 0°.

[0025] like Figure 5 As shown, the fan-shaped duct 100 is a contractile duct, the inlet diameter of which is larger than the outlet diameter, the outlet diameter is equal to the propeller diameter, and the duct contraction angle is not greater than 6°. Taking the propeller diameter D as a reference, the cross-section of the fan-shaped duct 100 is an airfoil cross-section, the cross-section chord length is 0.25-0.35D, and the cross-section thickness ratio is 0.10-0.13 (see Figure 3 ). The center line of the fan-shaped duct 100 is consistent with the center of the propeller shaft, that is, the longitudinal installation angle of the fan-shaped duct 100 is 0°.

[0026] like Figure 2-3 As shown, the cross-section settings at various positions of the fan-shaped duct 100 are different, and the airfoil sections of the upper and lower halves of the duct are set in reverse, wherein the section 101P of the upper connecting section 101 of the duct and the section 102P of the upper half 102 of the duct are set with the back of the blade facing outward, the section 104P of the lower half 104 of the duct and the section 105P of the lower connecting section 105 of the duct are set with the back of the blade facing inward, and the section 103P of the duct in the middle transition section 103 of the fan-shaped duct 100 adopts a symmetrical airfoil section. The section 200P of the blade 200 is consistent with 101P, and the back of the blade is set upward. This setting can better adapt to the characteristics of the propeller wake field and is more conducive to improving the wake field. Figure 3 The middle arrow represents the leaf section taken from that point, and P is a synonym for profile; the dotted line represents the back of the leaf, and the solid line represents the front of the leaf.

[0027] like Figure 1 , 3 As shown, the blade 200 is arranged horizontally in the circumferential direction, and its cross-sectional shape is consistent with the cross-sectional shape of the upper half of the duct, with the back of the blade facing upward. One end of the blade is fixed to the inner wall of the fan-shaped duct 100, and the other end is fixed to the surface of the stern 300. The cross-section of the blade 200 is an airfoil-shaped cross-section, and the cross-sectional chord length is slightly smaller than the cross-sectional chord length of the fan-shaped duct 100, which is 0.15-0.22D. In a preferred manner, the longitudinal installation angle α of the blade 200 is generally not greater than 9°, see Figure 5 .

[0028] In summary, the energy-saving semi-guide wheel in front of the propeller of the present invention is installed on the port side of the stern, close to the tail shaft outlet, and is mainly designed for right-hand propellers of medium and low-speed transport ships, which can effectively improve the inlet flow field of the left half plane of the propeller. The front energy-saving semi-guide wheel of the present invention can achieve better energy-saving effects through the special profile setting of the duct and the effective combination with the blades. According to this setting, the energy-saving semi-guide wheel in front of the propeller of the present invention is suitable for medium and low-speed transport ships equipped with right-hand propellers, including bulk carriers and liquid cargo ships of various tonnages, and can achieve an energy-saving effect of 3-5%.

[0029] The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. That is, all equivalent changes and modifications made according to the content within the scope of the patent application of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy-saving semi-guide wheel in front of a propeller, used in large medium and low-speed transport ships, characterized in that: The propeller of the large medium and low speed transport ship adopts a right-hand propeller design, and the propeller front energy-saving semi-guide wheel is installed on the port side of the tail of the large medium and low speed transport ship and near the front of the tail shaft outlet; The energy-saving semi-guide wheel in front of the propeller comprises: a fan-shaped duct installed on the port side of the stern of the hull near the tail shaft outlet, and blades arranged circumferentially in the duct; The fan-shaped duct is symmetrically arranged about a horizontal plane passing through the center of the propeller shaft, and the two ends of the blade are respectively fixed to the stern and the inner wall of the fan-shaped duct; and the fan-shaped duct can be divided into five parts welded together according to the circumferential position, namely, the upper connecting section of the duct, the upper half of the duct, the middle transition section of the duct, the lower half of the duct and the lower connecting section of the duct; and the design of the duct cross-section of the upper connecting section of the duct and the lower connecting section of the duct can generate a tangential inflow opposite to the rotation direction of the propeller, and the upper connecting section of the duct is connected to the upper part of the duct. The lower connecting section of the duct is set at a deviation from the preset angle directly below, the cross-section of the upper connecting section of the duct and the cross-section of the upper half of the duct are set with the back of the blade facing outward, the cross-section of the lower half of the duct and the cross-section of the lower connecting section of the duct are set with the back of the blade facing inward, and the cross-section of the middle transition section of the fan-shaped duct adopts a symmetrical airfoil cross-section; the back and front of the blades of the upper and lower half duct cross-sections are set in opposite directions, the back of the blade of the upper half duct cross-section faces outward, and the back of the blade cross-section faces upward, so as to generate pre-swirling inflow.

2. The energy-saving semi-guide wheel in front of the propeller according to claim 1 is characterized in that: The fan-shaped duct is integrated, and its circumferential angle range is 90-130°.

3. The energy-saving semi-guide wheel in front of the propeller according to claim 1 or 2, characterized in that: The fan-shaped duct is a contractile duct, the inlet diameter of which is larger than the outlet diameter, and the outlet diameter is equal to the propeller diameter.

4. The energy-saving semi-guide wheel in front of the propeller according to claim 3 is characterized in that: The contraction angle of the fan-shaped duct is not greater than 6°.

5. The energy-saving semi-guide wheel in front of the propeller according to claim 1 is characterized in that: The upper and lower duct sections are airfoil-shaped sections.

6. According to the energy-saving semi-guide wheel in front of the propeller of claim 1, the blades are arranged horizontally in the circumferential direction, and the longitudinal installation angle of the blades is not greater than 9°.

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