A parabolic flow guiding wing

Abstract

The present invention relates to a parabolic guide vane, which is organically composed of parabolic guide vanes with different opening directions and radial fins. The closed structure formed by the left-opening guide vane and the right-opening guide vane is mainly used to accelerate internal flow; the portion of the left-opening guide vane protruding from the closed structure is mainly used to improve unfavorable pre-swirl on the left side; and the radial fins are used to improve unfavorable pre-swirl and support the parabolic guide vane. The parabolic guide vane of the present invention, through precise coordination with the flow field, can efficiently change unfavorable axial (ship's forward direction) and circumferential (propeller rotation direction) flows, achieving the purpose of significantly improving energy conservation.

Description

Technical Field

[0001] The invention relates to a hydrodynamic guide wing in front of a ship's propeller, in particular to a parabolic guide wing for a ship. Background Art

[0002] Hydrodynamic energy-saving technology has been extensively researched over the past four decades, and a variety of energy-saving devices such as compensating ducts, rudder-attached thrust fins, and Mewis ducts have been developed and widely used on actual ships. In recent years, some new combined energy-saving devices have emerged, such as:

[0003] Application number CN201710152823.X discloses a "marine front guide vane" comprising a left arc wing plate, a right arc wing plate, and multiple guide vanes. However, the radius of the left arc wing plate is limited to 0.4-0.7R (R is the propeller radius), making it unable to modify unfavorable flows beyond 0.7R. Furthermore, the guide vanes are directly connected to the hull, destroying the favorable pre-swirl within 0.4R. Furthermore, the right and left arc wing plates are not enclosed below the propeller shaft, making it impossible to modify unfavorable flows within 0.4R below the propeller shaft, thus limiting the energy-saving effect.

[0004] Application number CN202111325560.0, titled "A Marine Helical Ducted Fin," proposes a solution for precisely coordinating ducted fins with the flow. By combining a helical duct with multiple radial fins, it significantly improves energy efficiency. However, due to its complex structure, its design, processing, and installation present challenges, limiting its practical application. Summary of the Invention

[0005] In response to the above-mentioned problems and limitations in the prior art, the present invention proposes a parabolic guide vane that is more compatible with the flow at the stern of the ship and has obvious energy-saving effects. Through the reasonable layout and proper connection of the parabolic guide vane and the radial fins, significant improvement and energy saving of the flow field at the stern of the ship are achieved.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is: a parabolic guide wing, which is organically composed of parabolic guide wings with different opening directions and radial fins, wherein the closed structure formed by the left-opening guide wing and the right-opening guide wing is used to accelerate the internal flow; the part of the left-opening guide wing protruding from the closed structure is used to improve the left chord unfavorable pre-rotation; the radial fins are used to improve the unfavorable pre-rotation and support the parabolic guide wing.

[0007] Furthermore, the parabolic guide fins are divided into upper and lower branches, which are located in different quadrants of the coordinate system, where the coordinate system is defined as: looking from the stern to the bow, the +X axis points to the starboard side of the hull, and the +Y axis is vertically upward; the different parabolic guide fins cooperate with the radial fins to form an organic parabolic guide fin.

[0008] Furthermore, viewed from the stern to the bow, the parabolic guide wing is composed of a group of left-opening parabolas, a group of right-opening parabolas and a number of fins, including left-opening and right-opening parabolic guide wings with their foci located on the X-axis and their vertices located on the +X and -X axes respectively, and radially distributed fins.

[0009] Furthermore, the control equation of the left-open parabolic main guide vane with the vertex located at the +X axis is x=a1y 2 +b1y+c1; the right-opening parabolic acceleration guide vane with the vertex located at the -X axis, its control equation is x=a2y 2 +b2y+c2, where a1, b1, c1 and a 2、 b 2、 c2 are unknown constants, and a1<0, a2>0; c1>0, c2<0.

[0010] Furthermore, the vertex C of the left open parabolic main guide vane with the vertex located at the +X axis is located on the positive half axis of the x axis, the propeller radius is set to R, the line segment between point C and the origin O is set to CO, and the length of CO is 0.4-0.7R; its upper branch is located in the first and second quadrants, and the intersection points of the upper branch and the +Y axis are set to B respectively, and the distance between point B and the origin O is 0.4-0.7R; the starting point is set to point A in the second quadrant, and the line segment between point A and the origin O is set to AO, The length of AO is 0.5-1.0R, and the angle between AO and the +Y axis is 15-75°; the lower branch of the left-opening parabolic main guide wing is located in the third and fourth quadrants, and the intersection with the -Y axis is set to D, and the distance between point D and the origin is 0.4-0.7R; the end point is set to point E located in the third quadrant, and the line segment between point E and the origin O is set to EO, the length of EO is 0.5-1.0R, and the angle between EO and the -Y axis is 15-75°.

[0011] Furthermore, the vertex H of the right open parabolic acceleration guide wing located on the port side of the hull is located on -X, the line segment between point H and the origin O is set to HO, the length of HO is 0.4-0.8R, its upper branch is located in the second quadrant, the starting point is set to point I, the line segment between point I and the origin O is set to IO, the length of IO is 0.4-0.9R, and the angle between IO and the +Y axis is 10-50°; its lower branch is located in the third quadrant, the end point is set to point J, the line segment between point J and the origin O is set to JO, the length of JO is 0.4-0.9R, and the angle between JO and the -Y axis is 10-50°, where R is the propeller radius.

[0012] Furthermore, the radial fins are distributed radially outward with the propeller axis as the center; at least two pre-swirl support fins are provided in the first quadrant and the fourth quadrant, with one end close to the origin connected to the hull and the other end away from the origin connected and not exceeding the left open parabolic main guide wing; at least one pre-swirl fin is provided in the second quadrant and the third quadrant, with one end close to the origin connected to the hull and the other end away from the origin connected and passing through the right open parabolic acceleration guide wing.

[0013] Furthermore, the pre-rotated fins located in the second and third quadrants have a cross-sectional chord length that varies along the span direction, and their outlines are formed by splicing two isosceles trapezoids with equal bases.

[0014] Furthermore, the parabolic guide wing branches individually or as a whole can translate or rotate within a plane.

[0015] Furthermore, the cross-sections of all parabolic guide wing branches are wing cross-sections, and the cross-sectional chord length, cross-sectional shape, and angle of the wing can be changed along the circumference of the wing.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a parabolic guide vane with obvious energy-saving effect. Through fine coordination with the flow field, the two parabolic guide vanes and fins are organically coordinated to efficiently change unfavorable axial (ship's forward direction) and circumferential (the same direction as the propeller's rotation) flows, thereby achieving the purpose of obvious energy-saving effect.

[0018] 1. Based on the characteristics of the flow field at the stern of the ship, the parabolic guide vane can be arranged in the most appropriate position and adopt the most reasonable shape and size to accurately change the unfavorable flow field at the stern of the hull, thereby improving the propulsion efficiency of the propeller and ultimately achieving the goal of significantly reducing the required main engine power at the same speed;

[0019] 2. The left opening parabolic main guide wing is located on the port side of the hull. The wing is arranged at the place where the unfavorable pre-spin of the hull is stronger; the left opening parabolic main guide wing is located on the starboard side of the hull. The right opening parabolic acceleration guide wing mainly plays the role of accelerating the axial flow inside the wing.

[0020] 3. The radially distributed fins are all arranged at the part of the hull where the unfavorable pre-spin is stronger. The chord length of the fins located on the port side of the hull becomes shorter as it approaches the hull to reduce the damage to the favorable pre-spin within 0.4R.

[0021] 4. The propulsion efficiency can be further improved by precise setting of the wing airfoil, size, installation position and angle.

[0022] The invention is organically formed by combining four sets of parabolic wings and has obvious energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Layout diagram of the marine parabolic guide wing of the present invention;

[0024] Figure 2 Schematic diagram of the division of favorable and unfavorable areas on the propeller disk;

[0025] Figure 3 This is a schematic diagram of the outline of the fin on the port side of the hull in the direction of its extension;

[0026] In the figure: 1. Left open parabolic main guide wing; 11. Upper branch of left open parabolic main guide wing; 12. Lower branch of left open parabolic main guide wing; 2. Right open parabolic pre-swirl guide wing; 21. Upper branch of right open parabolic pre-swirl guide wing; 22. Lower branch of right open parabolic pre-swirl guide wing; 3. Fins; 31, 32. Pre-swirl support fins; 33. Pre-swirl fins; 4. Hull. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments are combined with the attached Figure 1 and attached Figure 2 The present invention provides a parabolic guide vane for ships. The embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Any equivalent modifications of the present invention made by those skilled in the art fall within the scope of the appended claims.

[0028] In view of the problems and limitations of the existing technology ( Figure 3 ), the present invention has developed a parabolic guide wing that is more compatible with the flow at the stern of the ship and has obvious energy-saving effects. Through the reasonable layout and proper connection of the parabolic wing, significant improvement of the flow field at the stern of the ship and energy saving are achieved.

[0029] Example 1:

[0030] In the following embodiments, the marine parabolic guide wing mainly includes a left-opening parabolic main guide wing 1 with a focus on the positive half axis of the X-axis, an upper branch 11 of the left-opening parabolic main guide wing, a lower branch 12 of the left-opening parabolic main guide wing, a right-opening parabolic accelerating guide wing 2 with a focus on the negative half axis of the X-axis, an upper branch 21 of the right-opening parabolic accelerating guide wing, a lower branch 22 of the right-opening parabolic accelerating guide wing, fins 3, pre-spin support fins 31, 32, pre-spin fins 33, and a hull 4.

[0031] The parabolic guide wing is arranged in front of the propeller and close to the tail of the ship of the propeller, wherein the cross section of the wing is a wing profile.

[0032] like Figure 1As shown, the focus of the left-open parabolic main guide vane 1 is located on the x-axis, and the control equation is x=a1y 2 +b1y+c1, which runs through the four quadrants of the coordinate system, wherein the left-opening parabolic main guide wing 1 includes the left-opening parabolic main guide wing upper branch 11 and the left-opening parabolic main guide wing lower branch 12. The directrix of the parabola is perpendicular to the positive axis of the X-axis; the left-opening parabolic main guide wing 1 does not directly overlap the hull 4. The vertex C of the left-opening parabolic main guide wing is located on the positive semi-axis of the x-axis, and the length of CO is 0.5R. According to Figure 2 The size of the unfavorable flow area on the starboard side of the center propeller disk is determined; its upper branch is located in the first and second quadrants, and the intersection points of the upper branch and the positive axis of the Y axis are set to B, and the distance between point B and the origin O is 0.5R; the starting point is set to point A in the second quadrant, the propeller radius is set to R, the length of AO is 1.0R, and the angle α between AO and the positive axis of the Y axis is 55°; the lower branch of the left open parabolic main guide wing is located in the third and fourth quadrants, and the intersection point with the negative axis of the Y axis is set to D, and the distance between point D and the origin is 0.5R; the end point is set to point E in the third quadrant, the length of EO is 1.0R, and the angle β between EO and the negative axis of the Y axis is 55°. The lengths of AO and EO and the angles α and β between the Y axis are calculated based on Figure 2 The size and intensity distribution of the unfavorable flow area on the port side of the center propeller disk are determined. Among them, a1, b1, and c1 are unknown constants.

[0033] Furthermore, the vertex H of the right open parabolic acceleration guide wing located on the port side of the hull is located on the negative half axis of the x-axis, and the control equation is x = a2y 2 +b2y+c2, the length of HO is 0.5R; its upper branch is located in the second quadrant, the starting point is set as point I, the length of IO is 0.55R; its lower branch is located in the third quadrant, the end point is set as point J, the length of JO is 0.55R. The lengths of HO, IO, and JO are based on Figure 2 The size and intensity distribution of the favorable flow area on the port side of the central propeller disk are determined. 2、 b 2、 c2 are constants to be determined.

[0034] Furthermore, the radial pre-swirl support fin on the starboard side of the hull is located in the first and fourth quadrants, with the end close to the origin connected to the hull and the other end away from the origin connected and not exceeding the left open parabolic main guide vane. The connection points are set as points F and G, the length of FO is 0.6R, the angle between FO and the positive axis of the Y axis is 60°, the length of GO is 0.6R, and the angle between GO and the negative axis of the Y axis is 60°. The lengths of FO and GO and the angle between the Y axis are calculated based on the following equations: Figure 2 The size and intensity distribution of the unfavorable flow area on the starboard side of the center propeller disk are determined.

[0035] Furthermore, the radial pre-swirl support fin on the port side of the hull is located in the second quadrant, with the end close to the origin connected to the hull and the other end away from the origin connected and passing through the right open parabolic acceleration guide fin. The connection is set as point H, the length of HO is 0.5R, the end point is set as point K, the length of KO is 0.9R, and the angle between HO, KO and the positive axis of the Y axis is 80°; the length of HO, KO and the angle between the Y axis are calculated according to Figure 3 The size and intensity distribution of the unfavorable flow area on the port side of the center propeller disk are determined.

[0036] Furthermore, the chord length of the fin on the port side of the hull is shortened close to the hull side to reduce the damage to the favorable pre-spin within 0.4R.

[0037] Furthermore, the focus of the left-open parabolic main guide fin with the vertex located on the starboard side of the hull is located on the positive half axis of the x-axis, and the control equation is x = a1y 2 +b1y+c1, each control parameter a1, b1, c1 is based on Figure 2 The favorable pre-swirl area S and unfavorable pre-swirl area T of the middle propeller disk are determined; the left open parabolic main guide wing is located on the starboard side of the hull and mainly plays the role of accelerating the axial flow inside the wing; it is located on the port side of the hull and is arranged at the place where the unfavorable pre-swirl of the hull is stronger.

[0038] Furthermore, the focus of the parabolic acceleration guide wing on the right side of the port side of the hull is located on the negative half axis of the x-axis, and the control equation is x = a2y 2 +b2y+c2, each control parameter a2, b2, c2 according to Figure 2 The low-speed area on the port side of the midship hull is determined; the right-hand open parabolic acceleration guide vane primarily accelerates the axial flow within the wing and avoids disrupting the favorable flow on the propeller disc in the direction opposite to the propeller's rotation, thereby improving the propeller's propulsion efficiency. Where a1<0, a2>0; c1>0, c2<0.

[0039] Furthermore, a number of fins are radially distributed outward with the propeller axis as the center; the fin located on the port side of the hull is connected to and passes through the right open parabolic acceleration guide wing, and is arranged at Figure 2 The unfavorable pre-swirl flow is improved at the port side of the middle propeller disk where the unfavorable pre-swirl flow is stronger. The fin located on the starboard side of the hull is connected to and does not pass through the left open parabolic main guide wing. Figure 2 Improve the unfavorable pre-swirl flow at the starboard inner side of the center propeller disk where the unfavorable pre-swirl is stronger.

[0040] Furthermore, based on the principle of maximum pre-swirl and minimum drag, the chord length of the left-open parabolic main guide wing 1 is greater than the chord length of the radial fin 3 and the chord length of the right-open parabolic acceleration guide wing 2, and the chord lengths of the guide wing and fin sections remain unchanged along the circumferential direction.

[0041] Furthermore, the arrangement of the profiles of the various guide vanes and fins is determined by the flow conditions at the stern of the hull. The guide vanes primarily accelerate the low-speed zone and improve the pre-swirl flow on the propeller disk, while the fins primarily serve to significantly reduce or eliminate adverse pre-swirl and connect the wing to the hull. To achieve better energy-saving effects, the chord lengths of the guide vanes and fins can gradually change from the inner radius to the outer radius; depending on the ship type, the chord length of the guide vanes can be greater than the chord length of the fins or the chord length of the guide vanes can be less than the chord length of the fins; the above arrangement helps maximize the energy-saving effect.

[0042] The specific implementation method of the parabolic guide wing of the present invention is as follows:

[0043] First, based on market research and shipowner needs, a target ship was determined. The main dimensions and technical indicators are as follows: total length: 314.6m, beam: 52.5m, designed draft: 18m, displacement: 230,000t, speed 12.5kn, propeller rotation direction: right hand, propeller diameter: 9.6m, propeller design speed: 58.9r / min.

[0044] Then, the first embodiment of the hydrodynamic energy-saving device is determined as follows:

[0045] The longitudinal distance from the trailing edge of the energy-saving device (parabolic guide vane) to the propeller disk is 1.35m;

[0046] The focus of the left-open parabolic main guide vane 1 is on the x-axis, and the control equation is x = -0.305y 2 +2.4, the distance between A and the origin O, the length of AO is 1.0R, and the angle with the positive axis of the Y axis is 60°; the distance between C and the origin O, the length of CO is 0.5R, the distance between E and the origin O, the length of EO is 1.0R, and the angle with the negative axis of the Y axis is 60°.

[0047] Right opening parabolic acceleration guide vane 2, the control equation is x = 1.05y 2 -3.36, the distance between H and the origin O, and the length of HO is 0.7R. The fins 3 are radially distributed outward from the propeller axis. The pre-swirl support fins 31 are arranged in the first quadrant, with an angle of 45° to the positive X-axis; the pre-swirl support fins 32 are arranged in the fourth quadrant, with an angle of 30° to the positive X-axis; and the pre-swirl fins 33 are arranged in the second quadrant, with an angle of 15° to the negative X-axis.

[0048] The chord length of the fin is smaller than that of the guide vane, and the chord length of the wing section remains constant along the circumference, with each fin having the same chord length. This energy-saving device design can reduce ship fuel consumption by 4%-8%.

[0049] Example 2 (such as Figure 2), based on Example 1, the entire structure is rotated 5° counterclockwise about the origin, and pre-swirl fins 33 are arranged in the third quadrant, with an angle of 10° between the pre-swirl fins 33 and the negative X-axis. The chord length of the fins is greater than the chord length of the guide vanes, and the chord lengths of all wings are the same. The energy savings of Example 1 can be further increased by 1-2%.

[0050] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A parabolic guide vane, characterized in that: It is composed of parabolic guide vanes with different opening directions and radial fins, wherein the closed structure formed by the left opening guide vane and the right opening guide vane is used to accelerate the internal flow of the closed structure; the part of the left opening guide vane protruding from the closed structure is used to improve the unfavorable pre-spin of the left chord; the radial fins are used to improve the unfavorable pre-spin and support the parabolic guide vane; the parabolic guide vane is set in front of the propeller and close to the tail of the ship where the propeller is located. When viewed from the stern to the bow, the parabolic guide vane consists of a group of left-opening parabolas, a group of right-opening parabolas and a number of fins, including a left-opening parabolic main guide vane with a focus on the X axis and a vertex on the +X axis, a focus on the X axis and a vertex on the -X axis, and a right-opening parabolic main guide vane with a focus on the X axis and a vertex on the -X axis. The right-open parabolic acceleration guide wing on the axis and the radially distributed fins, where the coordinate system is defined as: looking from the stern to the bow, the +X axis points to the starboard side of the hull, the +Y axis is vertically upward, and the radial fins are centered on the propeller axis and distributed radially outward.

2. The parabolic guide vane according to claim 1, characterized in that: The parabolic guide fins are divided into two branches, an upper branch and a lower branch, which are respectively located in different quadrants of the coordinate system. The different parabolic guide fins cooperate with the radial fins to form a parabolic guide fin.

3. The parabolic guide vane according to claim 1, characterized in that: The left-open parabolic main guide vane with the vertex located at the +X axis has a control equation of x=a1y 2 +b1y+c1; the right-opening parabolic acceleration guide vane with the vertex located at the -X axis has a control equation of x=a2y 2 +b2y+c2, where a1, b1, c1 and a 2、 b 2、 c2 are unknown constants, and a1 <0, a2 >0; c1>0, c2<0.

4. The parabolic guide vane according to claim 1, characterized in that: The vertex C of the left open parabolic main guide wing with the vertex located on the +X axis is located on the positive half axis of the x axis, the propeller radius is set to R, the line segment between point C and the origin O is set to CO, and the length of CO is 0.4-0.7R; its upper branch is located in the first and second quadrants, and the intersection points of the upper branch and the +Y axis are set to B respectively, and the distance between point B and the origin O is 0.4-0.7R; the starting point is set to point A located in the second quadrant, and the line segment between point A and the origin O is set to AO, the length of AO is 0.5-1.0R, and the angle between AO and the +Y axis is 15-75°; the lower branch of the left open parabolic main guide wing is located in the third and fourth quadrants, and the intersection point with the -Y axis is set to D, and the distance between point D and the origin is 0.4-0.7R; the end point is set to point E located in the third quadrant, and the line segment between point E and the origin O is set to EO, The length of EO is 0.5-1.0R, and the angle between EO and -Y axis is 15-75°.

5. The parabolic guide vane according to claim 1, characterized in that: The vertex H of the right open parabolic acceleration guide wing located on the port side of the hull is located on -X, the line segment between point H and the origin O is set as HO, the length of HO is 0.4-0.8R, its upper branch is located in the second quadrant, the starting point is set as point I, the line segment between point I and the origin O is set as IO, the length of IO is 0.4-0.9R, and the angle between IO and the +Y axis is 10-50°; its lower branch is located in the third quadrant, the end point is set as point J, the line segment between point J and the origin O is set as JO, the length of JO is 0.4-0.9R, and the angle between JO and the -Y axis is 10-50°, where R is the propeller radius.

6. The parabolic guide vane according to claim 2, characterized in that: At least two pre-swirl support fins are provided in the first quadrant and the fourth quadrant, with one end close to the origin connected to the hull and the other end away from the origin connected to and not exceeding the left open parabolic main guide fin; at least one pre-swirl fin is provided in the second quadrant and the third quadrant, with one end close to the origin connected to the hull and the other end away from the origin connected to and passing through the right open parabolic acceleration guide fin.

7. The parabolic guide vane according to claim 6, characterized in that: The pre-rotated fins located in the second and third quadrants have a cross-sectional chord length that varies along the span direction, and their outline is the splicing of two isosceles trapezoids with equal bases.

8. The parabolic guide vane according to claim 2, characterized in that: The branches of the parabolic guide vane can translate or rotate individually or as a whole within a plane.

9. The parabolic guide vane according to claim 2, characterized in that: The cross-sections of the branches of the parabolic guide wing are all wing cross-sections, and the cross-sectional chord length, cross-sectional shape and angle of the wing are variable along the circumference of the wing.

Images