WO2013115658A1 - Hélice - Google Patents

Hélice Download PDF

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Publication number
WO2013115658A1
WO2013115658A1 PCT/NZ2013/000004 NZ2013000004W WO2013115658A1 WO 2013115658 A1 WO2013115658 A1 WO 2013115658A1 NZ 2013000004 W NZ2013000004 W NZ 2013000004W WO 2013115658 A1 WO2013115658 A1 WO 2013115658A1
Authority
WO
WIPO (PCT)
Prior art keywords
propeller
unshrouded
blade
flow
cylinder
Prior art date
Application number
PCT/NZ2013/000004
Other languages
English (en)
Inventor
Robert Davidson
Original Assignee
Propeller Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Propeller Technology Ltd filed Critical Propeller Technology Ltd
Publication of WO2013115658A1 publication Critical patent/WO2013115658A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/26—Blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency

Definitions

  • the invention relates to a propeller for a substantially incompressible fluid.
  • Propellers act to either move fluid through an object or to move an object through fluid, thus a fan may move air through a duct to create a ventilation flow, an aircraft propeller may move air past an aircraft both to propel it forwards and to create airflow over the wings. While the aerodynamics of a standard propeller can be designed by following the standard design procedures for such a propeller this will always result in a standard propeller with standard efficiency and standard drag characteristics. The design of a propeller from first principles of aero or hydrodynamic flow calculations is something which is only now beginning to be possible using supercomputers and development by such means is not yet practical.
  • the present invention provides a solution to this and other problems which offers advantages over the prior art or which will at least provide the public with a useful choice.
  • cylinder as used in this specification includes the end case where the cylinder has a diameter of zero, namely a straight line.
  • the invention consists in an unshrouded bladed propeller having a central rotational axis, the propeller for use immersed in a substantially
  • the highest velocity fluid created within the flow by the propeller occurs within the axially projected disc of the propeller and does not diverge axially outwardly of the propeller diameter within one propeller diameter downstream of the propeller trailing edge.
  • the propeller has at least one blade, the blade or blades having a front and a rear surface where at least one of these surfaces is a surface which is at least a section of the boundary surface produced by a fixed length straight line affixed at one end point to the surface of a cylinder and rotated about that end point along a plane fixedly aligned to the cylinder axis while the cylinder is rotated at a constant rate.
  • the cylinder has a diameter greater than zero.
  • the at least one surface is produced when the cylinder rotates through
  • the at least one surface is produced when the cylinder rotates through 360 degrees while the line rotates through 180 degrees.
  • the at least one propeller blade is of constant thickness.
  • the at least one propeller blade is affixed to a body allowing the propeller blades or blades to be rotated.
  • the body is a central cylinder.
  • the body is an external torus.
  • the propeller blade is symmetrical in projected axial contour.
  • a bell or sine shaped boss extends around the propeller around the width of the propeller blade intersection with the body.
  • FIG. 1 is a diagram assisting in explaining the propeller design in accordance with a first preferred embodiment of the invention.
  • FIG. 2 is a diagram of a product of the diagram of FIG. 1.
  • FIG. 3 is a perspective view of a propeller blade shape produced using the technique described in FIGs 1 and 2
  • FIG. 4 is a side view of the propeller blade shape of FIG. 3.
  • FIG. 5 is a top view of the propeller blade shape of FIG. 3.
  • FIG. 6 is an end view of the propeller blade shape of FIG. 3
  • FIG. 7 is an end view of a section of the propeller blade of FIGs 3, 4 and 5.
  • FIG. 8 is an end view of FIG. 7
  • FIG. 9 is a perspective view of FIG. 7
  • FIG. 10 is a perspective view similar to FIG. 3 but with two blades on a hub.
  • FIG. 11 is a side view of FIG. 10
  • FIG. 12 is a side view of a section of FIG. 10
  • FIG. 13 is a top view of the section of FIG. 10
  • FIG. 14 is a perspective view of the propeller of FIGs 12 and 13.
  • FIG. 15 is a view of the water flow past a known propeller.
  • FIGs. 16 to 18 are further views of the propeller of FIG. 1 at successively later stages in the flow.
  • FIG. 19 is a view of the water flow at right angles to the propeller axis.
  • FIG. 20 is a view of the inventive propeller and the water flow towards it.
  • FIGs 22 to 24 are further views of the inventive propeller of FIG. 9 at successively later stages in the flow.
  • FIG. 25 is a view of the inventive propeller and the water flow at right angles to the propeller axis. Description of the Invention
  • FIG. 1 shows a side view of a line 101 having ends 103, 104 representing either the exterior surface of a cylinder or a single line.
  • a straight line 105 may be rotated in the plane of the drawing about fixed point 103 through positions including 106, 107, 108 and 109 to produce a fan shaped surface 110, better seen in FIG. 2.
  • the line 101 is rotated either about the axis of the cylinder if line 101 represents a cylinder or about the line itself then the line describes a three dimensional boundary surface seen in FIG. 3 (perspective view) and FIG. 4 (left side view) and FIG. 5 (top view) where the boundary surface 1 1 1 is shown as having sufficient thickness to be capable of acting as a propeller blade.
  • the surface produced may alternatively be considered as at least a section of the surface traced out by a radius of a sphere to a loxodrome on the surface of the sphere.
  • the axial line 101 is shown in FIGs 3, 4 and 5 as a small diameter cylinder with ends 103, 104.
  • the ends of the propeller blade 1 11 are aligned with the axis, presenting a shape reminiscent of a scroll, while the central point 102 on the cylinder axis is the point at which the blade 11 1 reaches maximum distance from the central axis. If a fluid impinges with the blade 11 1 along the axis of the cylinder 103, 104 it can be seen that the entrainment of the fluid with the propeller could be expected to be comparatively gentle and similarly the detrainment is also comparatively gentle. This is due to what is effectively an in-turning leading edge and an out-turning trailing edge on the propeller blade.
  • FIG. 6 shows an end view of the propeller blade of FIG. 3 which appears as a cardioid shape in this view.
  • Dashed line circle 112 indicates a section to be "cut” along the axis of cylinder 103 from this blade which appears in FIG. 7, 8 and 9.
  • the propeller blade shown as a side view in FIG. 7, as a perspective view in FIG. 8 and as a top view in FIG. 9 has an outline which is a symmetrical section on the dashed circle 1 12 of FIG 5.
  • This shape 1 13 is integrated into a hub 114 and at a distance, looks very like a blade of a conventional propeller.
  • FIGs 3, 4 and 5 show only a single blade clearly as many blades as are necessary can be used and as long as they include a surface generated from the simultaneous angular rotation of a line together with the rotation of the lines base point a boundary surface including the advantages of the invention will be generated.
  • FIG. 10 shows a dual bladed propeller using the design of FIGs 3, 4 and 5 and having blades 1 11 and 1 17 spaced 180 degrees apart on a hub 1 18.
  • FIG. 11 shows a side view of the dual bladed propeller. Lines 12-12 indicate the section of this propeller shown in FIGs 12, 13 and 14.
  • FIGs 12, 13 and 14 show a simple section of the dual bladed propeller of FIGs 10 and 11, with FIG. 12 showing the side view, FIG. 8 the top view and FIG. 14 a perspective view. Again the in-turning of the leading edge is clearly shown, this edge being a product of the surface generated originally.
  • the simple section shown in FIGs 12, 13 and 14 has sharp tip points and a leading edge which is placed at 90 degrees to any impinging fluid flow. This is likely to create a disturbance in the fluid flow which is undesirable, and typically the leading and trailing edges of a blade will be taken on other than a simple section of the surface of a whole blade in order to provide curved leading and trailing edges in a side view. If the curve extends further forwards at the intersection of the blade root of the blades 1 1 1, 117 with the hub 1 18 then the inwards curve of the leading edge and the outwards curve of the trailing edge appears accentuated, although the same boundary surface is still being followed.
  • the propeller blade boundary surface is generated from the rotation of a straight line about a turning cylinder it is amenable to construction by rolling sheet metal such as stainless steel to form and then welding the blades so produced to a hub. Equally it may be constructed from a CAD (computer aided design) drawing by 3D printing in plastic and use of a sand cast or lost wax casting process to produce an aluminium or bronze propeller or by a CNC (computer numerical control) milling process.
  • CAD computer aided design
  • Tests of water propellers including blades with such boundary surfaces and of constant thickness show that under power such blades entrain water in a path barely extending outside the propeller diameter and have higher cavitation resistance than conventional propellers.
  • the efficiency of the inventive propellers is greater than that of conventional propeller designs.
  • FIGs. 15 through 19 show a prior art non-cavitating non-surface-piercing propeller of a typical three blade design.
  • Such propellers or propellers of very similar design are in common use on non-planing vessels or vessels of normal fineness operating up to or at the maximum hull speed (normally approximated as v hu ⁇ where Vhuii is the approximate maximum hull or displacement speed in knots and LWL is the length of a vessel at the waterline measured in feet).
  • Such propellers are normally designed to operate in a non-cavitating state (that is, the loading on the propeller should not be such as to pull a vacuum over a portion of the blade) since transient cavitation can cause substantial blade erosion.
  • a vessel speed range with the maximum design input power there may be cavitation at some point locations on the propeller as result of interference from the vessel structure.
  • FIGs 15 to 24 ignore such effects and are the results of a
  • CFD Computational Fluid Dynamics
  • FIG. 15 shows a simulation of the operation of a standard propeller in an ideal flow of water undisturbed by propeller shaft, shaft struts or the vessels hull and rudder. All of these degrade the performance of a propeller.
  • the propeller has three blades 151 of conventional design with a boss 152 and is rotating at 1000 rpm at a speed of 2.75 metres per second relative to the water. This is perhaps typical of a 15 metre vessel with a small diesel engine at economical cruise speed.
  • the flow lines such as 153 show water approaching at 2.75m/s just as the flow closest to the propeller is beginning to be sucked in to the propeller by water exiting it.
  • the water in the close zone is at just over 4 m/s.
  • the flow arrows 154 are shaded to indicate the flow speed with flow from 2.75 m/s for the lightest color to 6.0 m/s for the darkest color and therefore demonstrate the vector flow of fluid.
  • Each flow line can be considered as having a vector component along the propeller axis, a radial vector component and a circumferential vector component. We apologise to the reader because this will not reproduce well, but no other method of showing vector flow proved as illustrative.
  • FIG. 16 shows a slightly later stage of entrainment in which a vortex of flow lines is evident, and in which the maximum velocity above 5.3 m/s is being produced at the propeller tips.
  • FIG. 17 shows an entrainment stage which is slightly later again and in which the flow lines exiting the propeller are beginning to diverge outwards from the axis of the propeller while still in a lesser vortex.
  • the propeller will also be throwing off propeller tip vortexes and the back of the tip of the blades will be close to cavitation.
  • the vortexes result in increasing entrainment of the outer flow lines which were originally outside the propeller diameter.
  • FIG. 18 finally shows the general smoothing of the flow, still with a vortex trend, and still outwards, but slowly stabilising.
  • the flowline velocity at the areas of greatest velocity 181 are well outside the diameter of the propeller. It should be noted that very few of the original flowlines are within the diameter of the propeller, an indication that the inner "core" of water is highly turbulent. Some of this turbulence is due to the propeller boss, but much is simply the result of the creation of a vortex at the edges of the propeller flow.
  • FIG. 19 shows a side view of the flow from the propeller.
  • the general flow is outwards with a strong vortex trend as shown by the most prevalent flowlines 181 (remembering that the view also shows flowlines on the far side of the propeller).
  • the table below shows the distance between the flow lines originating at the maximum diameter of the propeller versus the distance downstream from the propeller of these flow lines in terms of the propeller diameter. It shows that these flow lines diverge. Table 1
  • the table below shows the maximum velocity of the flow from the propeller across a radius of the propeller (measured in terms of the diameter of the propeller) the specified diametral distance downstream from the propeller trailing edge.
  • the zero values on the propeller axis and at the 0.15 diameter radial distance indicate that the flow is sufficiently turbulent that it cannot be traced.
  • FIGs 20 to 25 show the inventive propeller in the same environment, namely at lOOOrpm in a 2.75 m/s flow.
  • the propeller was designed as in FIG. 14, namely a clipped truncated version of the propeller of FIG. 10.
  • FIG. 20 shows the propeller with two blades 201 and a boss 202 with flow lines 203.
  • Flow lines 204 are within the rotational area of the propeller and entering the zone of its influence, very similar to FIG. 1.
  • FIG. 21 shows the flow change as the flow lines meet the rotating propeller blades 201.
  • flow lines within the influence of the flow around the propeller such as 212 the flow can be seen to be almost purely rotational.
  • flow outside the propeller rotational area such as 21 1 are being entrained inwards towards the extended propeller rotational axis.
  • FIG. 22 shows that flow lines 221 exiting at the trailing edge of a propeller blade 201 are redirected at a slightly lower speed than during the transit across the face of the propeller blades while flowlines 211 from outside the propeller zone are being entrained inwards into the higher velocity flow. It is notable that the exiting flow is largely axial.
  • FIG. 23 shows the linear flow pattern developing as a comparatively slowly rotating vortex stream 231 with entrainment of other flow lines 21 1 outside of the propeller rotational area.
  • FIG. 24 shows the start of the dissipation of the stream, although it should be noted that the central flow 241 remains essentially linear with a mild vortex component.
  • FIG. 25 shows a side view of the flow lines from this propeller.
  • all flow lines 252 within the propeller disc of the rotational area of propeller blades 201 have initially both a rotational component and a component towards the axis of the propeller.
  • Within one propeller diameter downstream of the end of the propeller there is no flowline exiting from the propeller itself which does not fall within the propeller diameter. Following this distance the flow slows and starts to dissipate within the entrained flow at 251.
  • the table below shows the distance between the flow lines originating at propeller maximum diameter versus the distance downstream from the propeller in terms of the propeller diameter, that is, the convergence or divergence within one propeller diameter of the propeller trailing edge.
  • the table below shows the velocity of the flow from the propeller across a diameter of the propeller one diameter downstream from the propeller trailing edge.
  • FIG. 20 shows a flow analysis of a differing propeller in differing circumstances where the flow is higher and the propeller is operating close to cavitation. Again it can be seen that in addition to a stronger rotary or vortex component than the example of
  • Tests of water propellers including blades with such boundary surfaces and of constant thickness show that under power such blades entrain water in a path barely extending outside the propeller diameter and have higher cavitation resistance than conventional propellers as well as lower pressure loadings per unit area.
  • the efficiency of the inventive propellers is also greater than that of conventional propeller designs.
  • the blades create an energetic flow which takes the fluid with it.
  • the energetic flow pattern would have a gradient towards the focal point of the shape. This would tend to draw the fluid towards the centre and away from the blades.
  • the blades because of their shape, are theorised to set up a four dimensional multiple wave pattern in time and space which triggers the release of low level energy from the hydrogen molecule. Any point on any of these multiple waves travel in a spiral in the direction of the axis but in opposite rotation to the axis and at a constant velocity through the spiral.
  • the hydrogen molecule starting at a relatively slow speed and increases its velocity as it passes through the blades, this results in the hydrogen molecule which is carrying the rest of the medium with it travelling in a straight line parallel to the axis and exiting at a high velocity.
  • the attraction of the wave pattern to the hydrogen molecule results in a pulling motion by the propeller.
  • the material of which the propeller may be made can be somewhat more relaxed than is usual. Because the propeller does not cavitate in normal use and has a low pressure loading across most of the surface it may be made of plastics or fibreglass construction.
  • the propeller of the invention is used in the propulsion of water vessels or in the production of rotary motion from a water flow.
  • the present invention is therefore industrially applicable.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

La présente invention se rapporte à une surface de pale d'hélice représentant au moins une section de la surface tracée par un rayon d'une sphère jusqu'à une loxodromie sur la surface de la sphère. L'écoulement à travers un disque d'hélice utilisant de telles surfaces de pale comprend une composante vectorielle vers l'axe de l'hélice pour tout l'écoulement s'effectuant à travers le disque d'hélice et sur une distance en aval de l'hélice.
PCT/NZ2013/000004 2012-01-31 2013-01-31 Hélice WO2013115658A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NZ59794112 2012-01-31
NZ597941 2012-01-31
NZ60154912 2012-07-31
NZ601549 2012-07-31

Publications (1)

Publication Number Publication Date
WO2013115658A1 true WO2013115658A1 (fr) 2013-08-08

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PCT/NZ2013/000004 WO2013115658A1 (fr) 2012-01-31 2013-01-31 Hélice

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WO (1) WO2013115658A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111114727A (zh) * 2020-01-16 2020-05-08 兰州理工大学 一种流体螺旋推力驱动的推进器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0122726B1 (fr) * 1983-03-17 1986-07-09 Robert Davidson Surfaces faisant contact avec du fluide et dispositifs les incorporant
US4921404A (en) * 1984-10-12 1990-05-01 Holmberg Arnold C V Propellors for watercraft

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0122726B1 (fr) * 1983-03-17 1986-07-09 Robert Davidson Surfaces faisant contact avec du fluide et dispositifs les incorporant
US4921404A (en) * 1984-10-12 1990-05-01 Holmberg Arnold C V Propellors for watercraft

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111114727A (zh) * 2020-01-16 2020-05-08 兰州理工大学 一种流体螺旋推力驱动的推进器
CN111114727B (zh) * 2020-01-16 2024-05-10 兰州理工大学 一种流体螺旋推力驱动的推进器

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