CN103910023A - Novel efficient hydrofoil - Google Patents
Novel efficient hydrofoil Download PDFInfo
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- CN103910023A CN103910023A CN201410134718.XA CN201410134718A CN103910023A CN 103910023 A CN103910023 A CN 103910023A CN 201410134718 A CN201410134718 A CN 201410134718A CN 103910023 A CN103910023 A CN 103910023A
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Abstract
The invention provides a novel efficient hydrofoil. The novel efficient hydrofoil comprises hydrofins and a hydrofoil strut. The hydrofins are fixedly mounted below a naval ship through the hydrofoil strut, and the outer surfaces of the hydrofins are provided with antidrag structures composed of rough belts, grooves, pits or texture structures. The hydrofins with the antidrag structures have high lift-drag ratio when moving in the water, frictional drag and viscous drag of the hydrofoil to the water can be reduced, energy efficiency of driving delivery tools such as foilcrafts can be improved, and the novel efficient hydrofoil has the advantages that ship navigation speed is improved and energy conservation and emission reduction are realized.
Description
Technical field
The present invention relates to hydrofoil assembly, more particularly, relate to a kind of new and effective hydrofoil.
Background technology
Hydrofoil boat or hydrofoil boat are the vehicle in the water that can carry out navigating by water at a high speed.Support is equipped with in the bottom of hull, and support below is provided with hydrofoil plate, and hydrofoil plate is immersed in water wholly or in part.According to hydromechanical principle, the position that flow velocity is larger, pressure is less.In the time that boats and ships navigate by water in water, water is for hydrofoil plate rapid flow, and the water velocity of its upper surface of process is large, the water velocity of lower surface is little, and the upper and lower surface of hydrofoil plate has just formed pressure difference like this, when pressure difference is by force to a certain extent time, hull will be elevated, and even exceeds the water surface.The volume that hull is immersed in water reduces, and the resistance of suffered water is also corresponding significantly to be reduced, and like this, under identical propulsive force, the boats and ships that hydrofoil has been installed can reach higher speed.High speed naval vessels technology with other is compared, and the major advantage of hydrofoil boat (being mainly entirely to soak type) is under comparatively severe sea condition, to navigate by water, and the mountain peak of ship body is winnowed with a dustpan less.And the wave making producing while navigating by water is at a high speed comparatively few, lower on the impact on bank.
Due to the requirement of energy-saving and emission-reduction now, whole shipping community and shipbuilding circles have reached new height for the requirement of energy consumption index.The resistance that how to reduce navigation for shipbuilding is also a direction much studying institutional research always, and the reducing of ship resistance can be issued to speed faster at rating horsepower, reaches the object of energy-saving and emission-reduction.Although installation hydrofoil can effectively improve the route speed of boats and ships, still has at present many problems to have to be solved.Such as hydrofoil is when the underwater exercise, upper lower aerofoil all contacts with water.In the time that water flows through hydrofoil, due to the viscosity of water itself, can form a boundary 1ayer on hydrofoil surface.Boundary 1ayer is a thin layer, and it exists the flow region of very large velocity gradient and curl near hydrofoil surface along hydrofoil surface normal direction.Viscous stress is resistance to the water body of boundary 1ayer, so along with water body flows backward along object plane, the water body in boundary 1ayer can slow down gradually, supercharging.Due to the continuity of water body flow, boundary 1ayer can flow through more low speed water body by thickening within one time.Therefore in boundary 1ayer, exist adverse pressure gradient, be flowing under adverse pressure gradient effect, can further slow down, the kinetic energy of the water body in last whole boundary 1ayer be all not enough to permanent maintain to flow carry out downstream always, so that can be contrary with the velocity reversal of potential barrier in its speed of body surface somewhere, produce adverse current.This adverse current can be squeezed boundary 1ayer in potential barrier, causes the unexpected thickening of boundary 1ayer or separation.Separation of boundary layer can make resistance rise, and particularly because the pressure difference of position water body before and after hydrofoil rises, makes pressure drag become large.Resistance rises and will cause that speed declines, and does not have the effect that hydrofoil should play.
In addition, hydrofoil and incoming flow have certain angle of attack, and wing section has camber, thereby produce lift.The kinematic velocity of hydrofoil improves constantly, negative pressure on aerofoil just constantly declines, in the time that negative pressure is brought down below the saturated steam pressure of water at temperature at that time, there is bubble in the water on local aerofoil, in the time that bubble arrives higher-pressure region with water movement, bubble is received to push to shrink and is even crumbled and fall, and is accompanied by the Emergence and Development of bubble and the cyclic process of crumbling and fall, and is the process of cavitation.Cavitation is a kind of very harmful phenomenon, the consequences such as its meeting precocity physical disturbance, increase noise, and can cause that resistance increases and lift is unstable, even cause disaster accident.
Summary of the invention
Technical matters to be solved by this invention is to provide the hydrofoil that a kind of performance is more excellent, this hydrofoil can be avoided the difficulty of prior art medium or low resistance power hydrofoil, reduce friction drag and the viscous resistance of hydrofoil to water, increase the energy efficiency that drives the means of deliverys such as hydrofoil boat, in improving ship speed, reach the beneficial effect of energy-saving and emission-reduction.
Correspondingly, the present invention is not providing a kind of new and effective hydrofoil to solve the problems of the technologies described above in the restrictive embodiment of tool, this hydrofoil comprises hydrofoil plate and hydrofoil pillar, hydrofoil plate is fixedly mounted on the lower end of hydrofoil pillar, the upper end of hydrofoil pillar is fixedly mounted on the hull below of naval vessels, the outside face of hydrofoil plate is provided with drag reduction structure, the wing section (cross section of working direction while being parallel to hydrofoil motion) of hydrofoil plate is airfoil or arc or crescent, drag reduction structure can be the rough strip that is distributed in hydrofoil plate surface, rough strip can be continuous whole piece, also can be interrupted several, multi-disc rough strip can be laterally or parallel longitudinal distributes or title array format regular distribution, also can be to be randomly dispersed within on the outside face of hydrofoil plate, show that according to test rough strip is at 10%~30% chord length place being positioned at apart from hydrofoil plate leading edge, its width is 5%~20% chord length, highly can get good invention effect for 0.05mm~0.2mm.
Except rough strip, drag reduction structure can also adopt and be arranged on the groove on hydrofoil plate surface and crisscross latticed texture structure.Groove and texture structure can be that linear pattern can be also shaped form, or random lines shape, and groove and texture structure can be horizontal, parallel longitudinal distributions in the distribution on hydrofoil plate surface, can be to be also distributed in disorderly on the outside face of hydrofoil plate.
In numerous embodiment of the present invention, as optimization selection, drag reduction structure should adopt the bowl configurations that is distributed in hydrofoil plate surface.The quantity of pit can be one, can be also multiple.These pits be shaped as one or more the combination in circular pit, oblong pits, polygon pit and irregularly shaped pit.When multiple pit, pit can be following several at the arrangement mode of the outside face of hydrofoil plate: align in length and breadth arrangement, criss-cross arrangement, irregular alignment.The depth range of pit can be obtained more satisfactory drag-reduction effect in the time of 10mm~40mm.Pit can be selected at the area occupation ratio on hydrofoil plate surface in 5%~60% scope.
Boundary 1ayer when hydrofoil moves in water body, according to the Reynolds number difference of local flow field, the fluid in boundary 1ayer can be divided into laminar flow or turbulent flow.Laminar flow normally in the boundary 1ayer on smooth hydrofoil plate surface, and current in the boundary 1ayer of rough hydrofoil plate are turbulent flows.The boundary 1ayer of turbulent flow is subject to the impact of adverse pressure gradient less, so after the separation point of the boundary 1ayer on rough hydrofoil plate surface leans on relatively, its viscosity drag on the contrary more smooth hydrofoil plate is lower, pressure drag can significantly reduce especially.
This external hydrofoil plate surface arranges drag reduction structure, can increase the smooth turbulent flow on hydrofoil plate surface, makes turning point in advance, significantly promotes the fluid field pressure on hydrofoil plate surface, and delay cavitation and occur, and less on the lift impact of hydrofoil.
Compared with prior art, usefulness of the present invention is:
1. can effectively postpone boundary separation point, reduce resistance, under normal circumstances, when hydrofoil boat navigation, reynolds number Re can reach more than 105, be far longer than the requirement of the Re=60 that separation of boundary layer occurs, so in the time that hydrofoil boat normally navigates by water, the separation phenomenon of boundary 1ayer can occur, and drag reduction structure on hydrofoil can play the effect of postponing separation of boundary layer point, reduce the viscosity drag on hydrofoil, the energy consumption while having reduced hydrofoil boat navigation;
2. significantly promote the fluid field pressure on hydrofoil plate surface, delay cavitation and occur, effectively reduce that physical disturbance, resistance increase, lift is unstable and the adverse consequences such as noise increase.
Brief description of the drawings
Fig. 1 is the structural representation of the specific embodiment of the invention one;
Fig. 2 is that hydrofoil lift is with angle of attack variation histogram (abscissa is angle of attack angle);
Fig. 3 is that hydrofoil resistance is with angle of attack variation histogram (abscissa is angle of attack angle);
Fig. 4 is that hydrofoil resistance is with angle of attack variation broken line graph (abscissa is angle of attack angle);
Fig. 5 is that hydrofoil 1ift-drag ratio is with angle of attack variation broken line graph (abscissa is angle of attack angle);
Fig. 6 is that fixing angle of attack Water Under wing drag changes broken line graph (abscissa is the speed of a ship or plane) with the speed of a ship or plane;
Fig. 7 is that fixing angle of attack Water Under wing 1ift-drag ratio changes broken line graph (abscissa is the speed of a ship or plane) with the speed of a ship or plane;
Fig. 8 is specific embodiment two structural representations;
Fig. 9 is specific embodiment three structural representations;
Figure 10 is specific embodiment four structural representations.
Detailed description of the invention
According to specific embodiments and the drawings, this present invention is described further below.
Low resistance hydrofoil as depicted in figs. 1 and 2, comprises hydrofoil pillar 1 and hydrofoil plate 2, and the wing section of hydrofoil plate 2 is shaped as airfoil type, and the span of hydrofoil plate is 15m, and chord length is 3m, and on the surface of hydrofoil plate 2, circular pit 3 is being arranged in alignment in length and breadth.The degree of depth of these pits 3 is 30mm, and pit 3 is 50% at the area occupation ratio on hydrofoil plate 2 surfaces.
Due to traditional habit, it is believed that more smooth surperficial friction drag is less, and good material is as better in the effect meeting of the anti-cavitations such as titanium alloy material, therefore traditional R&D direction focuses mostly on and is reducing by the profile of improving hydrofoil the resistance that it is subject to, adopt better material to resist cavitation effect, but effect or undesirable, or improve the cost of manufacture of hydrofoil.The present inventor has overcome traditional technology prejudice---and-coarse surface can increase friction drag, drag reduction structure will be provided with on the surface of hydrofoil plate 2, produce turbulent boundary 1ayer, postpone boundary separation point, shift to an earlier date turning point, no matter reduced aspect the resistance that hydrofoil is subject to, still reduced the harm aspect of cavitation, all obtain good effect, and in experiment, obtained confirmation.
Under the condition of fixing speed of a ship or plane V=20m/s, to the smooth hydrofoil of hydrofoil provided by the present invention and same size and profile suffered lift (L under the different angles of attack, unit: newton), resistance (R, unit: newton), 1ift-drag ratio (K) tests, and can obtain following experimental result:
Lift (L), resistance (R), 1ift-drag ratio (K) observed data of the smooth hydrofoil of table 1-1 tradition
The angle of attack | L(N) | R(N) | K |
0 | 2826.194392 | 7222.073574 | 0.39133 |
3 | 45115.42233 | 8589.438942 | 5.25243 |
5 | 76782.85787 | 8668.696498 | 8.85749 |
6 | 93015.70574 | 8687.20853 | 10.99839 |
7 | 109047.414 | 8770.476949 | 12.43346 |
8 | 125011.2142 | 8815.957461 | 14.18011 |
Lift (L), resistance (R), 1ift-drag ratio (K) observed data of table 1-2 hydrofoil of the present invention
The angle of attack | L(N) | R(N) | K |
0 | 2228.87036 | 5574.07128 | 0.39986 |
3 | 45164.70515 | 6815.78273 | 6.62648 |
5 | 76742.92862 | 6964.77417 | 11.0187 |
6 | 92942.20538 | 6979.53639 | 13.3163 |
7 | 109126.79475 | 7006.83628 | 15.5743 |
8 | 120997.89375 | 7048.74047 | 17.1658 |
From table 1-1 and Fig. 2 and Fig. 3, the pit 3 on hydrofoil plate 2 surfaces does not almost exert an influence to the lift of hydrofoil, but the suffered resistance of hydrofoil but obviously reduces.Again resistance suffered hydrofoil and 1ift-drag ratio are studied separately.Can be found out by Fig. 4 and Fig. 5, along with the change of the angle of attack is large, all corresponding increases of resistance that this specific embodiment and traditional smooth hydrofoil are suffered, but the suffered resistance of traditional smooth hydrofoil is larger than this specific embodiment all the time.The 1ift-drag ratio that Fig. 5 more clearly demonstrates this specific embodiment is larger than traditional smooth surface hydrofoil all the time, is more conducive to the navigation of the naval vessels that hydrofoil provided by the present invention has been installed.
Under the fixing angle of attack (6 °) condition, change beneficial effect of the present invention fluid velocity (the simulation speed of a ship or plane) and carry out further simulated experiment in order further to verify.Can obtain following observed data:
Lift, resistance and the 1ift-drag ratio of the smooth hydrofoil of table 1-3 tradition are with fluid velocity delta data
Speed (m/s) | L(N) | R(N) | K |
15 | 52449.514 | 3088.6234 | 16.98151 |
20 | 93015.705 | 8687.2085 | 10.99839 |
22.5 | 118261.114 | 5066.2598 | 23.34288 |
25 | 121008.691 | 7220.4245 | 16.75922 |
Lift, resistance and the 1ift-drag ratio of table 1-4 hydrofoil of the present invention are with fluid velocity delta data
Speed (m/s) | L(N) | R(N) | K |
15 | 51145.983 | 2447.5882 | 20.8108 |
20 | 92942.20538 | 6979.53639 | 13.3163 |
22.5 | 116806.026 | 4153.461 | 28.31453 |
25 | 120510.251 | 4782.5431 | 25.19793 |
Known in conjunction with Fig. 6 and Fig. 7, fluid velocity approaches the route speed of hydrofoil boat routine at 15~25m/s() in scope, the overall 1ift-drag ratio of hydrofoil of the present invention is all greater than the 1ift-drag ratio of conventional smooth hydrofoil.
Therefore can reach a conclusion, the invention enables the overall 1ift-drag ratio of hydrofoil to be significantly improved, optimize the performance of hydrofoil plate, obtain expected effect.
In this specific embodiment, the degree of depth of pit 3 can be selected within the scope of 10~40mm, gets respectively pit depth and be 10mm, 15mm, 20mm, 30mm, 35mm, 40mm test, and all can obtain the technique effect of desirable raising 1ift-drag ratio.
In addition, the shape of pit 3 also can adopt one or more the group form in circular pit, oblong pits, polygon pit and irregularly shaped pit, can adopt rule or irregular alignment, all can obtain the technique effect of desirable raising 1ift-drag ratio.
Pit, is got 5%, 10%, 20%, 30%, 45%, 50%, 55%, 60% and is tested at the area occupation ratio on hydrofoil plate surface between 5%~60%, and effect is all very good.
Specific embodiment two as shown in Figure 8, only be that with the difference of specific embodiment one the drag reduction structure on its hydrofoil plate 2 surfaces is a slice rough strips 4, this rough strip is at 10%~30% chord length place being positioned at apart from hydrofoil plate leading edge, and its width is 20% chord length, is highly 0.1mm.After tested, it also can obtain desirable raising 1ift-drag ratio, reduces the technique effect of cavitation phenomenon.
Specific embodiment three as shown in Figure 9, is only that with the difference of specific embodiment one the drag reduction structure on its hydrofoil plate 2 surfaces is several grooves that be arranged in parallel 5, and the degree of depth of these grooves is 30mm, is parallel to the setting of hydrofoil leading edge.
Specific embodiment four as shown in figure 10, is only that with the difference of specific embodiment one the drag reduction structure on its hydrofoil plate 2 surfaces is staggered texture structures of a slice 6, and the degree of depth of these texture structures is 5mm.
Above embodiment is for understanding the present invention's; it is not limitation of the present invention; about the those of ordinary skill in field; on the basis of technical scheme described in claim; can also make multiple variation or moulding; such as the various drag reduction structures of above-mentioned specific embodiment can be regularly arranged shown in specific embodiment; also can be irregular alignment; it can also be multiple drag reduction textural association; for example pit and rough strip, pit and groove, pit and texture structure etc., these variations or modification should be understood to still belong to protection scope of the present invention.
Claims (10)
1. a new and effective hydrofoil, comprise hydrofoil plate and hydrofoil pillar, hydrofoil plate is fixedly mounted on the lower end of hydrofoil pillar, the upper end of hydrofoil pillar is fixedly mounted on the hull below of naval vessels, it is characterized in that: the outside face of described hydrofoil plate is provided with drag reduction structure, described drag reduction structure is one or more combinations in rough strip, groove, texture structure or the pit that is distributed in hydrofoil plate surface, and the minimum number of described rough strip, groove, texture structure or pit is one.
2. new and effective hydrofoil according to claim 1, is characterized in that: described pit is one or more combinations in circular pit, oblong pits, polygon pit and irregularly shaped pit.
3. new and effective hydrofoil according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face of the hydrofoil plate proper alignment of aliging in length and breadth.
4. new and effective hydrofoil according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face criss-cross arrangement of hydrofoil plate.
5. new and effective hydrofoil according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face irregular alignment of hydrofoil plate.
6. according to the new and effective hydrofoil described in claim 1 to 5 any one, it is characterized in that: the degree of depth of described pit is 10mm~40mm.
7. new and effective hydrofoil according to claim 6, is characterized in that: the area occupation ratio of described pit is 5%~20%.
8. new and effective hydrofoil according to claim 1, it is characterized in that: the cross section outline that is parallel to naval vessels working direction of described hydrofoil plate is airfoil type, described rough strip is positioned at 10%~30% chord length place apart from hydrofoil plate leading edge, the width of rough strip is 5%~20% chord length, height 0.05mm~0.2mm.
9. new and effective hydrofoil according to claim 1, is characterized in that: described groove is positioned at the surface of described hydrofoil plate and is parallel to the leading edge of described hydrofoil plate.
10. new and effective hydrofoil according to claim 1, is characterized in that: described texture structure is crisscross latticed texture structure, is distributed in the surface of described hydrofoil plate.
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Cited By (5)
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CN106151182A (en) * | 2015-04-21 | 2016-11-23 | 水科远大(北京)交通设计院有限公司 | Water conservancy diversion configuration |
CN107244379A (en) * | 2017-06-30 | 2017-10-13 | 哈尔滨工业大学 | It is a kind of to suppress underwater sailing body and the flow control method of hydrofoil surface cavitation phenomenon |
CN107264717A (en) * | 2017-06-06 | 2017-10-20 | 哈尔滨工程大学 | A kind of bionical hydrofoil suitable for foilcraft |
CN109178192A (en) * | 2018-09-21 | 2019-01-11 | 惠安县圆周率智能科技有限公司 | A kind of gas blowing type foilcraft |
CN110427817A (en) * | 2019-06-25 | 2019-11-08 | 浙江大学 | A kind of hydrofoil cavitation feature extracting method based on vacuole framing Yu sound texture analysis |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN110427817A (en) * | 2019-06-25 | 2019-11-08 | 浙江大学 | A kind of hydrofoil cavitation feature extracting method based on vacuole framing Yu sound texture analysis |
CN110427817B (en) * | 2019-06-25 | 2021-09-07 | 浙江大学 | Hydrofoil cavitation feature extraction method based on cavitation image positioning and acoustic texture analysis |
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