CA1141240A - Duct combined with a ship's propeller having blade tip barrier plates - Google Patents
Duct combined with a ship's propeller having blade tip barrier platesInfo
- Publication number
- CA1141240A CA1141240A CA000363717A CA363717A CA1141240A CA 1141240 A CA1141240 A CA 1141240A CA 000363717 A CA000363717 A CA 000363717A CA 363717 A CA363717 A CA 363717A CA 1141240 A CA1141240 A CA 1141240A
- Authority
- CA
- Canada
- Prior art keywords
- duct
- propeller
- blade
- ship
- barrier plates
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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
- B63H1/28—Other means for improving propeller efficiency
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
- B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
- B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
-
- 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
- B63H1/16—Propellers having a shrouding ring attached to blades
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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)
- Advancing Webs (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
- Cleaning In General (AREA)
- Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A duct is provided for ship's propellers with blade tips having barrier plates extending transversely therefrom.
The duct is effectively arranged to direct a fluid stream in substantially shock-free contact with such plates. The barrier plates are adequately arranged with respect to the trailing edge of the duct so as to get the highest propeller efficiency.
When the propeller is rotating, the barrier plates describe a body of revolution which is a kind of extension of the after side of the duct.
A duct is provided for ship's propellers with blade tips having barrier plates extending transversely therefrom.
The duct is effectively arranged to direct a fluid stream in substantially shock-free contact with such plates. The barrier plates are adequately arranged with respect to the trailing edge of the duct so as to get the highest propeller efficiency.
When the propeller is rotating, the barrier plates describe a body of revolution which is a kind of extension of the after side of the duct.
Description
O
This invention relates to ships propellers having blade tip barrier plates and more particularly to improving the efficiency of the propulsion of ships with propellers having - blades with tip barrier plates by means of combining a duct with such propellers.
The invention refers to fixed blade propellers and also to orientable blade (controlla~le pitch) propellers. The geometrical definitions herein included refer, for the orient-able blade propellers, to the position of the blades correspond-ing to the design pitch condition.
To impart finite circulation (or loadingl values to blade tip sections of a ship's propeller, it is necessary to give the propeller blades a very special geometry involving an uncommon pitch distribution along the radius, but this is not sufficient, since in addition it is also necessary to prevent the formation of vortices at the tips of the blades. To achieve this, the following techniques may be employed.
a) making the propeller operate inside a fixed nozzle or ~O duct having circular cross sections which are coaxial with the propeller, although with this technique tip vortices are not completely eliminated, due to the necessary clearance existing between blade tips and inner surface of duct.
b~ connecting a duct like the one mentioned in a) to the propeller blade tips, so that the duct rotates together with the : propeller although with this technique the efficiency of the pro-peller is very substantially reduced, becasue of the high viscous resistance of the rotating duct.
c) adding barrier or closing plates to the tip sections of the propeller blades, which plates can ~e imagined as cut out ' 1 from an iaeal surrounding duct like the one mentioned in a~ or in b) above.
Even when propeller blades are given the very special geometry which is required to get effectively finite circulation (or loading) at the tip sections, and are fitted with transverse barrier plates extending from the tips of the propeller blades so that, from a theoretical viewpoint, finite circulation ~or loading) values should have to be o~tained at the tip section of the propeller hlades, such circulation ~or loading) is not act-ually attained in practice because of the flow separation phe-nomena produced when the fluid contacts the barrier plates on the blade tips of the propeller while the propeller is driving - a ship. Consequently, the performance of this type of propeller has been always unsatisfactory up to now, its efficiency being lower than the efficiency of conventional propellers.
But the low propulsive efficiency of this type of pro-pellers is dramatically improved when the incoming fluid stream contacts the barrier plates under shock-free conditions regard-less of the ship's speed and the revolution rate of the propeller ~0 so that the a~ove mentioned flow separation phenomena are avoided.
An object of the invention is to provide suitable means to create such shock-free conditions in actual practice.
Another o~ject of the presentinvention to at least part-ially overcome the unsatisfactory performance of known ship's propellers having blade tip barrier plates extending longitudin-ally therefrom by providing duct in combination ~ith such pro-pellers. The duct is effectively arranged to direct a fluid stream in su~stantially shock-free contact with such plates. The - barrier plates are adequately arranged with respect to the trail-ing edge of the duct so as to get the highest propeller efficiency-.
This invention relates to ships propellers having blade tip barrier plates and more particularly to improving the efficiency of the propulsion of ships with propellers having - blades with tip barrier plates by means of combining a duct with such propellers.
The invention refers to fixed blade propellers and also to orientable blade (controlla~le pitch) propellers. The geometrical definitions herein included refer, for the orient-able blade propellers, to the position of the blades correspond-ing to the design pitch condition.
To impart finite circulation (or loadingl values to blade tip sections of a ship's propeller, it is necessary to give the propeller blades a very special geometry involving an uncommon pitch distribution along the radius, but this is not sufficient, since in addition it is also necessary to prevent the formation of vortices at the tips of the blades. To achieve this, the following techniques may be employed.
a) making the propeller operate inside a fixed nozzle or ~O duct having circular cross sections which are coaxial with the propeller, although with this technique tip vortices are not completely eliminated, due to the necessary clearance existing between blade tips and inner surface of duct.
b~ connecting a duct like the one mentioned in a) to the propeller blade tips, so that the duct rotates together with the : propeller although with this technique the efficiency of the pro-peller is very substantially reduced, becasue of the high viscous resistance of the rotating duct.
c) adding barrier or closing plates to the tip sections of the propeller blades, which plates can ~e imagined as cut out ' 1 from an iaeal surrounding duct like the one mentioned in a~ or in b) above.
Even when propeller blades are given the very special geometry which is required to get effectively finite circulation (or loading) at the tip sections, and are fitted with transverse barrier plates extending from the tips of the propeller blades so that, from a theoretical viewpoint, finite circulation ~or loading) values should have to be o~tained at the tip section of the propeller hlades, such circulation ~or loading) is not act-ually attained in practice because of the flow separation phe-nomena produced when the fluid contacts the barrier plates on the blade tips of the propeller while the propeller is driving - a ship. Consequently, the performance of this type of propeller has been always unsatisfactory up to now, its efficiency being lower than the efficiency of conventional propellers.
But the low propulsive efficiency of this type of pro-pellers is dramatically improved when the incoming fluid stream contacts the barrier plates under shock-free conditions regard-less of the ship's speed and the revolution rate of the propeller ~0 so that the a~ove mentioned flow separation phenomena are avoided.
An object of the invention is to provide suitable means to create such shock-free conditions in actual practice.
Another o~ject of the presentinvention to at least part-ially overcome the unsatisfactory performance of known ship's propellers having blade tip barrier plates extending longitudin-ally therefrom by providing duct in combination ~ith such pro-pellers. The duct is effectively arranged to direct a fluid stream in su~stantially shock-free contact with such plates. The - barrier plates are adequately arranged with respect to the trail-ing edge of the duct so as to get the highest propeller efficiency-.
-2-1 ~hen the propeller is rotating, the ~arrier plates describe a body of revolution which is a kind of extension of the after side of the duct.
SUMMARY OF THE INVENTION
The invention involves attaching a device to a ship's ` hull to force fluid contacting tip sections of the propeller blades to make such contact in about a parallel direction to the orientation of the barrier plates extending from such tip sections.
The invention further involves increasing the propulsive effici-ency of the propeller having blades designed to have finite cir-culation (or loading) values at their tip sections and havingblade tips fitted with fixed barrier plates, by directing a fluid stream to and past the barrier plates in a substantially shock-free manner.
To this end, in a first aspect the invention provides a com~ination of a ship's propeller of fixed blade or orientable blade type ~the geometrical definitions hereinafter included re-ferring in this case to the design pitch condition) in juxta-. position with a non-rotating duct, the propeller having an axis a diameter and a plurality of blades, each blade having, a basic generative line, a fixed plate at the tip section, and a back or suction side, the duct being coaxial with and displaced from said propeller and located on the back or suction side thereof, its after or downstream side being an extension of a geometric figure ideally generated ~by a cross-section of an axial plane, through . the basic generative line of a blade, with the fixed plate) on : rotation of said fixed plate about the axis, having an internal radius at a point adjacent to the fixed plate which is approxi-mately that of said geometric figure at a point which is closest 30 to said duct r providing means to direct a fluid stream toward
SUMMARY OF THE INVENTION
The invention involves attaching a device to a ship's ` hull to force fluid contacting tip sections of the propeller blades to make such contact in about a parallel direction to the orientation of the barrier plates extending from such tip sections.
The invention further involves increasing the propulsive effici-ency of the propeller having blades designed to have finite cir-culation (or loading) values at their tip sections and havingblade tips fitted with fixed barrier plates, by directing a fluid stream to and past the barrier plates in a substantially shock-free manner.
To this end, in a first aspect the invention provides a com~ination of a ship's propeller of fixed blade or orientable blade type ~the geometrical definitions hereinafter included re-ferring in this case to the design pitch condition) in juxta-. position with a non-rotating duct, the propeller having an axis a diameter and a plurality of blades, each blade having, a basic generative line, a fixed plate at the tip section, and a back or suction side, the duct being coaxial with and displaced from said propeller and located on the back or suction side thereof, its after or downstream side being an extension of a geometric figure ideally generated ~by a cross-section of an axial plane, through . the basic generative line of a blade, with the fixed plate) on : rotation of said fixed plate about the axis, having an internal radius at a point adjacent to the fixed plate which is approxi-mately that of said geometric figure at a point which is closest 30 to said duct r providing means to direct a fluid stream toward
3--O
1 said back or suction side of said propeller in substantially shock-free contact with each fixed plate, and having a length at its shortest point which is at least 5 percent of the pro-peller diameter and at most 2 times the propeller diameter.
In a second aspect, the invention provides a combin-ation according to the first aspect wherein the propeller has finite circulation ~or loading) values in its blade tip sections.
!' In a third aspect, the invention provides a combin-ation according to the second aspect wherein each fixea plate has a forward end and the duct has an after or downstream side, the forward end of each fixed plate being displaced by at least 5 millimeters from the after side of the duct.
In a fourth aspect, the invention provides a combin-ation according to the third aspect wherein said forward end is as close as possible to said after side or even overlapped with it.
In a fifth aspect, the invention provides a combin-ation according to the third aspect wherein the duct has a ~` streamlined configuration~
- 20 In a sixth aspect, the invention provides a combin-ation according to the third aspect wherein the duct has a cross-section which varies in size or configuration along its axis.
In a seventh aspect,the invention provides a com~in-ation according to the third aspect wherein the duct has a con-stant length or varies in length around its periphery.
In a eighth aspect, the invention provides a combin-ation according to the first aspect wherein the duct is mounted on and fixed to a hull of a ship.
In a ninth aspect, the invention provides a combin-ation according to the eighth aspect wherein the duct varies in
1 said back or suction side of said propeller in substantially shock-free contact with each fixed plate, and having a length at its shortest point which is at least 5 percent of the pro-peller diameter and at most 2 times the propeller diameter.
In a second aspect, the invention provides a combin-ation according to the first aspect wherein the propeller has finite circulation ~or loading) values in its blade tip sections.
!' In a third aspect, the invention provides a combin-ation according to the second aspect wherein each fixea plate has a forward end and the duct has an after or downstream side, the forward end of each fixed plate being displaced by at least 5 millimeters from the after side of the duct.
In a fourth aspect, the invention provides a combin-ation according to the third aspect wherein said forward end is as close as possible to said after side or even overlapped with it.
In a fifth aspect, the invention provides a combin-ation according to the third aspect wherein the duct has a ~` streamlined configuration~
- 20 In a sixth aspect, the invention provides a combin-ation according to the third aspect wherein the duct has a cross-section which varies in size or configuration along its axis.
In a seventh aspect,the invention provides a com~in-ation according to the third aspect wherein the duct has a con-stant length or varies in length around its periphery.
In a eighth aspect, the invention provides a combin-ation according to the first aspect wherein the duct is mounted on and fixed to a hull of a ship.
In a ninth aspect, the invention provides a combin-ation according to the eighth aspect wherein the duct varies in
-4-12~0 1 length along its periphery, its larges-t dimension, which may be extended forward in the form of fins, being at its highest elevation along the hull and its shortest dimension ~eing at its lowest elevation along the hull.
In a tenth aspect, the invention provides a method of increasing the propulsive efficiency of a propeller-impelled ship, wherein the propeller has blade tips with fixed barrier plates and is designed to have finite circulation (or loading) values at the blade tip sections, which comprises directing a substantially shock-free fluid stream to and past the barrier plates.
In an eleventh aspect, the invention provides a method according to the tenth aspect which comprises providing duct means to direct the fluid stream to an area circumscribed by the barrier plates, In a twelfth aspect, the invention provides a method according to the tenth aspect which comprises effectively ex-tending the fixed barrier plates ~ith a non-rotatable duct.
In athirteen~h aspect, the invention provides a method according to the tenth aspect and intended for orientable blade ~controllable pitch~ propellers, whereby the blade barrier plates may still fulfil their role at any blade position in spite of the fact that they become out of the extended surface of the after part of the duct, when each blade turns around its shaft.
In the fourteenth aspect, the invention provides a method according to the thirteenth aspect each blade barrier plate is tangent to a revolution surface which has the same axis as the turning shaft of the corresponding orientable blade of the propeller, and in such a way that said revolution surface is also tangent to the duct surface, and then as a consequence there-of the waterflow coming from the duct will enter in contact with 1 the barrier plates under practically shock-free conditions, at any position of the blades.
BRIEF DESCRIPTION OF TH~ DRAWINGS
.
Further o~ects and advantages o the invention will appear from the following description taken together with the accompanying drawings in which:
Figure 1 presents, in Figure l-A a schematic longitud-inal section and side view ~developed and expanded~ and in Figure l-B a corresponding radial view tdeveloped and expanded2 of a propeller blade having a shaped barrier or closing plate pro-jecting substantially from its blade tip.
Figures 2 to 9 present schematic longitudinal sections and side views (developed and expanded~ of propeller blades hav-ing variously shaped barrier or closing plates projecting sub-stantially transversely from the blade tips~
Figures 10 to 14 present schematic radial views (developed and expanded) of propeller blades having variously shaped ~arrier or closing plates projecting substan-tially trans-; versely from the ~lade tips.
Figure 15 presents a schematic aft view of a propeller having barrier or closing plates at its blade tips, Figure 16 presents a schematic side view of the pro-peller of Figure 15, It should be understood that the barrier or closing plates may be of any of the shapes shown in Figures 1 to 14 or of shapes similar to them.
Figure 17 provides a schematic side view representation of the combination of a duct with a propeller of the type ill-ustrated in Figure 15, Figures 18 to 22 provide schematic side views of ducts of various shapes according to the present invention.
1 Figure 23, represents a further view of the propeller and duct of figure 17, providing a schematic longitudinal section of the trailing edge of the duct and of the blade barrier or closing plates of the propeller whereby the relative position of the trailing edge of the duct is shown with respect to the blade barrier or closing plates of the propeller combined there-with.
Figures24 to 36 show views similar in nature to the view of Figure 23 providing schematic longitudinal section of the trailing edges of ducts of various shapes and of the blade barrier or closing plates of the propellers combined therewith, whereby their relative positions are shown.
'' Figure 37 schematically shows the underwater part of '; the stern of a ship fitted with a propeller combined with a duct ; of a type as the illustrated in figure 17. Several arrangements , of the sternframe profile in respect of the duct are indicated, ', and many others are possible. No structural supports for the , duct are shown. Although only a type of sternframe is shown, as ', an example all other types are also suitable to be fitted with `; 20 the same combination of duct and propeller.
' Figure 38 shows a schematic representation of a pro-peller having orientable blades.
Figure 3~ shows a schematic representation of Figure 38 the propeller together with a duct coupled to same. Also, - some possible revolution surfaces have been represented, all of '- them having the same axis as the orientable blade shaft.
- Throughout all the figures similarly num~ered elements represent the similar objects.,Element 1 is a propeller hub.
Element 2 is a propeller blade. Elements3 and 3a through 3i and 3j through 3p are barrier or closing plates. Elements4 and 4a 1 through 4f are ducts. Elements 5 and 5a through 5f are trailing edges o ducts. Element 6 is a ship's hull. Elements 7a through 7c are sternframe profiles, Element 8 is the blade turn-ing axis. Element 9 are possible revolution surfaces.
DETAILED DESCRIPTION OF THE INVENTION
In order to made sure thatfinite circulation (or ` loading~ is attained in practice at the blade tip sections of a ship's propeller having ~lades with substantial transverse pro-jections from the blade tips (barrier or closing or tip plates), a non-rotating duct is placed forward ~upstream) of the propeller.
The after (downstream) end or trailing edge of the duct has a circular section which is specifically adapted to the propeller.
The purpose of the duct is to direct the fluid (passing there-throughl in shock-free conditions and as smoothly as possible towards the barrier plates at the tip sections of the propeller ;; blades. The shape of the after end of the duct is designed so as to constitute an effective extension of the surface generat~d ;' by the barrler plates while the propeller is rotating.
The duct is coaxial with and displaced from the pro-peller. It is naturally on the back or suction side of the pro-~ peller so that it will direct towards the propeller the fluid upon which the propeller acts.
:.
As the barrier plates are variously designed, as shown ~y elements3a through 3i and 3j through 3p ~or combinations thereof~ in figures 1 to 14, they generate different geometric figures on propeller rotation. The barrier plates are so designed that the intersection with the ideal middle surface of the barrier plates of a plane perpendicular to the axis of the pro-peller is in the form of arc sections of a circle.
The duct can be more or less streamlined in shape. The 1 more streamlined it is, the less are the disadvantages produced in towing resistance of the ship due to incorporation of the duct~
The actual form of the duct and its precise relation-ship to the propeller are subject to variations in design, as shown by figures 17 to 22 which illustrate some differently-shaped ducts 4a through 4f and, as shown by figures 23 to 36, which illustrate diverse relationships between such ducts and the propeller with which they are associated ~see 5a through 5f).
; 10 However the form of the duct must be such as to avoid flow separation along its inner surface. Also, the form of the duct can be such as to produce more or less acceleration in the water-;, flow or fluid-stream passing therethrough. For each ship, there t~ill be an optimum degree of water-flow acceleration which will produce the best combination of hull efficiency and propeller efficiency, and the form of the duct can then be designed so as to achieve said optimum degree of acceleration.
- Finally, to obtain maximum efficiency from the com~in-ation duct-propeller, the shape and the position of the blade barrier plates relative to the trailing edge of the duct, not only axially, but also transversely and radially, should be such as to get the highest duct acceleration consistent with a low barrier plate viscous resistance, while always keeping the nec-essary ability to prevent the formation of tip vortices and the best shock-free contact conditions with the barrier plates of the fluid stream coming from the duct.
The combination of duct and propeller as described hereinbefore can be fitted to any kind of ship with any kind of sternframe~ The arrangement and positioning of same into the sternframe area may adopt many different forms. As an example _9_ 1 figure 37 presents a typical arrangement with one of the types of duct inside a very common type oE sternframe, several types of arrangement, 7a through 7c, of the sternframe profile in respect of the duct r being also shown, The number of blades on a ship's propeller and the num~er of propellers used to drive a ship vary; this invention is independent of such variance, that is, can be applied to pro-pellers with any number of blades, and can also be applied to each of the several propellers driving a ship.
Although propeller blades 2 have the required spécial geometry to achieve finite circulation ~or loading) at their - tip sections, and although said tip sections are provided with barrler plates, such as 3a through 3i and 3j through 3p (or ; combinations thereof), to permit having finite circulation (or loading) values at such tip sections, the desired circulation is not actually achieved in practice by providing such special geo~etry and such barrier plates. To provide suitable conditions for obtaining such circulation, a shock-free stream must be directed in contact with and past the barrier plates, Such shock-free flow is achieved by providing a duct, such as 4a through 4f immediately upstream of the propeller blades. The duct must be suitably adapted to the propeller design and to the hull lines r and also suitably coupled to the propeller blade tip barrier plates in a manner such as those illustrated in figures 23 to 36, ~ this couplingtof paramount importance for the efficiency of the propeller In fact this coupling of duct to propeller is really one of the more essential parts of the in-vention.
As descrihed herein~efore the after end of the duct placed forward of the propeller must be a kind of extension of O
the geometric surface ideally generated by the propeller blade barrier plates when rotating (or viceversa).
In the case of a controllable pitch propeller, the above requirement refers to the position of the blades corre-sponding to the design pitch condition, but when changing the blade orientation, the barrier plates become placed out of -the iaeal surface which is an extension of the after end of the duct.
In such a case, each barrier plate can still fulfil its role, if it remains tangential to a revolution surface whose mathematical axis is the same axis of the turning shaft of the ; corresponding blade of the propeller.
The above mentioned condition is herebelow better described, by means of the drawings presented in figures 38 and 39.
The required condition is that each barrier plate 3 be tangential to a revolution surface 9, selected in such a way that the duct surface 4 is also tangential to this very same revolution surface 9, thus permitting the waterflow coming from the duct, to enter in contact w;th the barrier plate under practically shock-free conditions.
The invention and its advantages are readily under-stood from the foregoing description. Various changes may be made in the process and apparatus without departing from the spirit and scope of the invention or sacrificing its material advantages. The process and apparatus hereinbefore described are merely illustrative of preferred embodiments of the invention. For a definition of the invention reference is made to the appended claims.
In a tenth aspect, the invention provides a method of increasing the propulsive efficiency of a propeller-impelled ship, wherein the propeller has blade tips with fixed barrier plates and is designed to have finite circulation (or loading) values at the blade tip sections, which comprises directing a substantially shock-free fluid stream to and past the barrier plates.
In an eleventh aspect, the invention provides a method according to the tenth aspect which comprises providing duct means to direct the fluid stream to an area circumscribed by the barrier plates, In a twelfth aspect, the invention provides a method according to the tenth aspect which comprises effectively ex-tending the fixed barrier plates ~ith a non-rotatable duct.
In athirteen~h aspect, the invention provides a method according to the tenth aspect and intended for orientable blade ~controllable pitch~ propellers, whereby the blade barrier plates may still fulfil their role at any blade position in spite of the fact that they become out of the extended surface of the after part of the duct, when each blade turns around its shaft.
In the fourteenth aspect, the invention provides a method according to the thirteenth aspect each blade barrier plate is tangent to a revolution surface which has the same axis as the turning shaft of the corresponding orientable blade of the propeller, and in such a way that said revolution surface is also tangent to the duct surface, and then as a consequence there-of the waterflow coming from the duct will enter in contact with 1 the barrier plates under practically shock-free conditions, at any position of the blades.
BRIEF DESCRIPTION OF TH~ DRAWINGS
.
Further o~ects and advantages o the invention will appear from the following description taken together with the accompanying drawings in which:
Figure 1 presents, in Figure l-A a schematic longitud-inal section and side view ~developed and expanded~ and in Figure l-B a corresponding radial view tdeveloped and expanded2 of a propeller blade having a shaped barrier or closing plate pro-jecting substantially from its blade tip.
Figures 2 to 9 present schematic longitudinal sections and side views (developed and expanded~ of propeller blades hav-ing variously shaped barrier or closing plates projecting sub-stantially transversely from the blade tips~
Figures 10 to 14 present schematic radial views (developed and expanded) of propeller blades having variously shaped ~arrier or closing plates projecting substan-tially trans-; versely from the ~lade tips.
Figure 15 presents a schematic aft view of a propeller having barrier or closing plates at its blade tips, Figure 16 presents a schematic side view of the pro-peller of Figure 15, It should be understood that the barrier or closing plates may be of any of the shapes shown in Figures 1 to 14 or of shapes similar to them.
Figure 17 provides a schematic side view representation of the combination of a duct with a propeller of the type ill-ustrated in Figure 15, Figures 18 to 22 provide schematic side views of ducts of various shapes according to the present invention.
1 Figure 23, represents a further view of the propeller and duct of figure 17, providing a schematic longitudinal section of the trailing edge of the duct and of the blade barrier or closing plates of the propeller whereby the relative position of the trailing edge of the duct is shown with respect to the blade barrier or closing plates of the propeller combined there-with.
Figures24 to 36 show views similar in nature to the view of Figure 23 providing schematic longitudinal section of the trailing edges of ducts of various shapes and of the blade barrier or closing plates of the propellers combined therewith, whereby their relative positions are shown.
'' Figure 37 schematically shows the underwater part of '; the stern of a ship fitted with a propeller combined with a duct ; of a type as the illustrated in figure 17. Several arrangements , of the sternframe profile in respect of the duct are indicated, ', and many others are possible. No structural supports for the , duct are shown. Although only a type of sternframe is shown, as ', an example all other types are also suitable to be fitted with `; 20 the same combination of duct and propeller.
' Figure 38 shows a schematic representation of a pro-peller having orientable blades.
Figure 3~ shows a schematic representation of Figure 38 the propeller together with a duct coupled to same. Also, - some possible revolution surfaces have been represented, all of '- them having the same axis as the orientable blade shaft.
- Throughout all the figures similarly num~ered elements represent the similar objects.,Element 1 is a propeller hub.
Element 2 is a propeller blade. Elements3 and 3a through 3i and 3j through 3p are barrier or closing plates. Elements4 and 4a 1 through 4f are ducts. Elements 5 and 5a through 5f are trailing edges o ducts. Element 6 is a ship's hull. Elements 7a through 7c are sternframe profiles, Element 8 is the blade turn-ing axis. Element 9 are possible revolution surfaces.
DETAILED DESCRIPTION OF THE INVENTION
In order to made sure thatfinite circulation (or ` loading~ is attained in practice at the blade tip sections of a ship's propeller having ~lades with substantial transverse pro-jections from the blade tips (barrier or closing or tip plates), a non-rotating duct is placed forward ~upstream) of the propeller.
The after (downstream) end or trailing edge of the duct has a circular section which is specifically adapted to the propeller.
The purpose of the duct is to direct the fluid (passing there-throughl in shock-free conditions and as smoothly as possible towards the barrier plates at the tip sections of the propeller ;; blades. The shape of the after end of the duct is designed so as to constitute an effective extension of the surface generat~d ;' by the barrler plates while the propeller is rotating.
The duct is coaxial with and displaced from the pro-peller. It is naturally on the back or suction side of the pro-~ peller so that it will direct towards the propeller the fluid upon which the propeller acts.
:.
As the barrier plates are variously designed, as shown ~y elements3a through 3i and 3j through 3p ~or combinations thereof~ in figures 1 to 14, they generate different geometric figures on propeller rotation. The barrier plates are so designed that the intersection with the ideal middle surface of the barrier plates of a plane perpendicular to the axis of the pro-peller is in the form of arc sections of a circle.
The duct can be more or less streamlined in shape. The 1 more streamlined it is, the less are the disadvantages produced in towing resistance of the ship due to incorporation of the duct~
The actual form of the duct and its precise relation-ship to the propeller are subject to variations in design, as shown by figures 17 to 22 which illustrate some differently-shaped ducts 4a through 4f and, as shown by figures 23 to 36, which illustrate diverse relationships between such ducts and the propeller with which they are associated ~see 5a through 5f).
; 10 However the form of the duct must be such as to avoid flow separation along its inner surface. Also, the form of the duct can be such as to produce more or less acceleration in the water-;, flow or fluid-stream passing therethrough. For each ship, there t~ill be an optimum degree of water-flow acceleration which will produce the best combination of hull efficiency and propeller efficiency, and the form of the duct can then be designed so as to achieve said optimum degree of acceleration.
- Finally, to obtain maximum efficiency from the com~in-ation duct-propeller, the shape and the position of the blade barrier plates relative to the trailing edge of the duct, not only axially, but also transversely and radially, should be such as to get the highest duct acceleration consistent with a low barrier plate viscous resistance, while always keeping the nec-essary ability to prevent the formation of tip vortices and the best shock-free contact conditions with the barrier plates of the fluid stream coming from the duct.
The combination of duct and propeller as described hereinbefore can be fitted to any kind of ship with any kind of sternframe~ The arrangement and positioning of same into the sternframe area may adopt many different forms. As an example _9_ 1 figure 37 presents a typical arrangement with one of the types of duct inside a very common type oE sternframe, several types of arrangement, 7a through 7c, of the sternframe profile in respect of the duct r being also shown, The number of blades on a ship's propeller and the num~er of propellers used to drive a ship vary; this invention is independent of such variance, that is, can be applied to pro-pellers with any number of blades, and can also be applied to each of the several propellers driving a ship.
Although propeller blades 2 have the required spécial geometry to achieve finite circulation ~or loading) at their - tip sections, and although said tip sections are provided with barrler plates, such as 3a through 3i and 3j through 3p (or ; combinations thereof), to permit having finite circulation (or loading) values at such tip sections, the desired circulation is not actually achieved in practice by providing such special geo~etry and such barrier plates. To provide suitable conditions for obtaining such circulation, a shock-free stream must be directed in contact with and past the barrier plates, Such shock-free flow is achieved by providing a duct, such as 4a through 4f immediately upstream of the propeller blades. The duct must be suitably adapted to the propeller design and to the hull lines r and also suitably coupled to the propeller blade tip barrier plates in a manner such as those illustrated in figures 23 to 36, ~ this couplingtof paramount importance for the efficiency of the propeller In fact this coupling of duct to propeller is really one of the more essential parts of the in-vention.
As descrihed herein~efore the after end of the duct placed forward of the propeller must be a kind of extension of O
the geometric surface ideally generated by the propeller blade barrier plates when rotating (or viceversa).
In the case of a controllable pitch propeller, the above requirement refers to the position of the blades corre-sponding to the design pitch condition, but when changing the blade orientation, the barrier plates become placed out of -the iaeal surface which is an extension of the after end of the duct.
In such a case, each barrier plate can still fulfil its role, if it remains tangential to a revolution surface whose mathematical axis is the same axis of the turning shaft of the ; corresponding blade of the propeller.
The above mentioned condition is herebelow better described, by means of the drawings presented in figures 38 and 39.
The required condition is that each barrier plate 3 be tangential to a revolution surface 9, selected in such a way that the duct surface 4 is also tangential to this very same revolution surface 9, thus permitting the waterflow coming from the duct, to enter in contact w;th the barrier plate under practically shock-free conditions.
The invention and its advantages are readily under-stood from the foregoing description. Various changes may be made in the process and apparatus without departing from the spirit and scope of the invention or sacrificing its material advantages. The process and apparatus hereinbefore described are merely illustrative of preferred embodiments of the invention. For a definition of the invention reference is made to the appended claims.
Claims (16)
1. A combination of a ship's propeller of fixed blade or orientable blade type (the geometrical definitions hereinafter included referring in this case to the design pitch condition) in juxtaposition with a non-rotating duct, the propeller having an axis, a diameter and a plurality of blades, each blade having a) a basic generative line b) a fixed plate at the tip section and e) a back or suction side, the duct d) being coaxial with and displaced from said propeller and located on the back or suction side thereof, e) its after or downstream side being an extension of a geometric figure ideally generated (by a cross-section of an axial plane, through the basic generative line of a blade, with the fixed plate) on rotation of said fixed plate about the axis, f) having an internal radius at a point adjacent to the fixed plate which is approximately that of said geometric figure at a point which is closest to said duct, g) providing means to direct a fluid stream toward said back or suction side of said propeller in substantially shock-free contact with each fixed plate, and h) having a length at its shortest point which is at least S percent of the propeller diameter and at most 2 times the propeller diameter.
2. A combination according to claim 1 wherein the pro-peller has finite circulation (or loading) values in its blade tip sections.
3. A combination according to claim 2 wherein each fixed plate has a forward end and the duct has an after or downstream side, the forward end of each fixed plate being displaced by at least 5 millimeters from the after side of the duct.
4. A combination according to claim 3 wherein said forward end is as close as possible to said after side or even overlapped with it.
5. A combination according to claim 3 wherein the duct has a streamlined configuration.
6. A combination according to claim 3 wherein the duct has a cross-section which varies in size or configuration along its axis.
7. A combination according to claim 3 wherein the duct has a constant length or varies in length around its periphery.
8. A combination according to claim 1 wherein the duct is mounted on and fixed to a hull of a ship.
9. A combination according to claim 8 wherein the duct varies in length along its periphery, its largest dimension, which may be extended forward in the form of fins, being at its highest elevation along the hull and its shortest dimension being at its lowest elevation along the hull.
10. A ship having a hull and a propeller, the propeller being in a combination according to claim 1 with a duct, and the duct being mounted on and fixed to the hull.
11. A ship having a hull and two or more propellers, each propeller being in a combination according to claim 1 with a duct.
12. A method of increasing the propulsive efficiency of a propeller-impelled ship, wherein the propeller has blade tips with fixed barrier plates and is designed to have finite circu-lation (or loading) values at the blade tip sections, which
12. A method of increasing the propulsive efficiency of a propeller-impelled ship, wherein the propeller has blade tips with fixed barrier plates and is designed to have finite circu-lation (or loading) values at the blade tip sections, which
Claim 12 continued:
comprises directing a substantially shock-free fluid stream to and past the barrier plates.
comprises directing a substantially shock-free fluid stream to and past the barrier plates.
13. A method according to claim 12 which comprises providing duct means to direct the fluid stream to an area circumscribed by the barrier plates.
14 A method according to claim 12 which comprises effectively extending the fixed barrier plates with a non-rotatable duct.
15. A method according to claim 12 and intended for orientable blade (controllable pitch) propellers, whereby the blade barrier plates may still fulfil their role at any blade position, in spite of the fact that they become out of the extended surface of the after part of the duct, when each blade turns around its shaft.
16. A method according to claim 15 wherein each blade barrier plate is tangent to a revolution surface which has the same axis as the turning shaft of the corresponding orientable blade of the propeller, and in such a way that said revolution surface is also tangent to the duct surface, and then as a consequence thereof the waterflow coming from the duct will enter in contact with the barrier plates under practically shock-free conditions, at any position of the blades.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ES485,667 | 1979-11-02 | ||
| ES485667A ES8100010A1 (en) | 1979-11-02 | 1979-11-02 | Tubular duct for a ship propeller |
| ES492531A ES8205166A2 (en) | 1980-06-18 | 1980-06-18 | Improvements in the propulsors that pose finite values of the circulation in the extremes of the blades (Machine-translation by Google Translate, not legally binding) |
| ES492,531 | 1980-06-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1141240A true CA1141240A (en) | 1983-02-15 |
Family
ID=26155994
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363717A Expired CA1141240A (en) | 1979-11-02 | 1980-10-31 | Duct combined with a ship's propeller having blade tip barrier plates |
Country Status (22)
| Country | Link |
|---|---|
| AR (1) | AR223734A1 (en) |
| AU (1) | AU534883B2 (en) |
| BR (1) | BR8007076A (en) |
| CA (1) | CA1141240A (en) |
| CU (1) | CU21557A3 (en) |
| DD (1) | DD153787A5 (en) |
| DE (1) | DE3041140A1 (en) |
| DK (1) | DK464580A (en) |
| EG (1) | EG14824A (en) |
| FI (1) | FI803369L (en) |
| FR (1) | FR2468499A1 (en) |
| GB (1) | GB2063378B (en) |
| GR (1) | GR71888B (en) |
| IE (1) | IE50173B1 (en) |
| IN (1) | IN153167B (en) |
| IT (1) | IT1146117B (en) |
| NL (1) | NL8005991A (en) |
| NO (1) | NO803273L (en) |
| NZ (1) | NZ195418A (en) |
| PL (1) | PL227599A1 (en) |
| PT (1) | PT72003B (en) |
| SE (1) | SE8007655L (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3615619A1 (en) * | 1985-06-24 | 1987-01-02 | Schiffbau Veb K | CONTROL DEVICE FOR INFLUENCING THE PROPELLER INFLOW IN SHIPS |
| EP0219364A1 (en) * | 1985-08-13 | 1987-04-22 | COMPANIA AUXILIAR DE NAVEGACION S.A. (AUXINAVE) Société dite: | Ship propellers |
| ATE106817T1 (en) * | 1989-11-15 | 1994-06-15 | Stichting Tech Wetenschapp | PROPELLER. |
| DE4138281C1 (en) * | 1991-11-02 | 1993-04-29 | Herbert Prof. Dr.-Ing. 5100 Aachen De Schneekluth | |
| GB0315247D0 (en) * | 2003-06-30 | 2003-08-06 | Redding John | Improvements in or relating to fluid flows and jets |
| CH699473A2 (en) * | 2008-08-27 | 2010-03-15 | Drs Drag Reduction Systems Sa | Device for channeling the water flow around the hub of a ship's propeller. |
| AU2014277656A1 (en) * | 2013-12-17 | 2015-07-02 | Ringprop Marine Ltd | Marine propellers |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR405384A (en) * | 1908-11-12 | 1909-12-28 | Basile Soldatencow | Improvements made to the propellers of air or water navigation devices, and devices including application |
| FR569801A (en) * | 1922-11-03 | 1924-04-18 | Gill Propeller Company Ltd | Improvements to propellers or equivalent components |
| FR894007A (en) * | 1941-01-20 | 1944-12-12 | Boat propulsion device | |
| DE941048C (en) * | 1941-12-28 | 1956-03-29 | Josef Neukamm | Guide nozzle for ships with screw drive |
| FR894822A (en) * | 1942-03-11 | 1945-01-08 | Propeller and its manufacturing process | |
| DE1628257A1 (en) * | 1966-06-16 | 1970-05-06 | Stroemungstechnik Ges | Process for deflecting, bundling or distributing flow media as well as suitable rotating guiding devices |
| NL7013069A (en) * | 1969-09-05 | 1971-03-09 | ||
| JPS5131489A (en) * | 1974-09-12 | 1976-03-17 | Akashi Funegata Kenkyusho Kk | Dakuto puropera |
-
1980
- 1980-10-24 GR GR63217A patent/GR71888B/el unknown
- 1980-10-27 FI FI803369A patent/FI803369L/en not_active Application Discontinuation
- 1980-10-27 CU CU8035356A patent/CU21557A3/en unknown
- 1980-10-29 IT IT50025/80A patent/IT1146117B/en active
- 1980-10-30 AR AR283074A patent/AR223734A1/en active
- 1980-10-30 SE SE8007655A patent/SE8007655L/en not_active Application Discontinuation
- 1980-10-30 NZ NZ195418A patent/NZ195418A/en unknown
- 1980-10-30 AU AU63855/80A patent/AU534883B2/en not_active Ceased
- 1980-10-31 NO NO803273A patent/NO803273L/en unknown
- 1980-10-31 PL PL22759980A patent/PL227599A1/xx unknown
- 1980-10-31 FR FR8023292A patent/FR2468499A1/en not_active Withdrawn
- 1980-10-31 DD DD80224878A patent/DD153787A5/en unknown
- 1980-10-31 DK DK464580A patent/DK464580A/en not_active Application Discontinuation
- 1980-10-31 BR BR8007076A patent/BR8007076A/en unknown
- 1980-10-31 PT PT72003A patent/PT72003B/en unknown
- 1980-10-31 CA CA000363717A patent/CA1141240A/en not_active Expired
- 1980-10-31 NL NL8005991A patent/NL8005991A/en not_active Application Discontinuation
- 1980-10-31 IE IE2263/80A patent/IE50173B1/en unknown
- 1980-10-31 DE DE19803041140 patent/DE3041140A1/en not_active Withdrawn
- 1980-11-01 IN IN1238/CAL/80A patent/IN153167B/en unknown
- 1980-11-01 EG EG80672A patent/EG14824A/en active
- 1980-11-03 GB GB8035257A patent/GB2063378B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IE50173B1 (en) | 1986-02-19 |
| SE8007655L (en) | 1981-05-03 |
| AU534883B2 (en) | 1984-02-16 |
| AU6385580A (en) | 1981-05-07 |
| NO803273L (en) | 1981-05-04 |
| DK464580A (en) | 1981-05-03 |
| DE3041140A1 (en) | 1981-05-14 |
| FR2468499A1 (en) | 1981-05-08 |
| IN153167B (en) | 1984-06-09 |
| PT72003A (en) | 1980-11-01 |
| IE802263L (en) | 1981-05-02 |
| CU21557A3 (en) | 1987-06-09 |
| IT1146117B (en) | 1986-11-12 |
| DD153787A5 (en) | 1982-02-03 |
| IT8050025A0 (en) | 1980-10-29 |
| EG14824A (en) | 1985-03-31 |
| BR8007076A (en) | 1981-05-05 |
| PT72003B (en) | 1981-10-13 |
| NL8005991A (en) | 1981-06-01 |
| NZ195418A (en) | 1984-11-09 |
| GR71888B (en) | 1983-08-05 |
| FI803369L (en) | 1981-05-03 |
| AR223734A1 (en) | 1981-09-15 |
| GB2063378A (en) | 1981-06-03 |
| GB2063378B (en) | 1983-06-29 |
| PL227599A1 (en) | 1981-08-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |