DE2924613A1 - FLUID DRIVEN OR A FLUID DRIVING ROTOR - Google Patents

Description

19 705/6 40 / Ko

Nederlandse Organization voor Toegepast Natuurwetenschappelijk Onderzoek ten behoeve van Nijverheid, Handel en Verkeer (Nijverheisorganisatie TNO), Bankaplein 1, THE HAGUE, The Netherlands

A fluid-driven rotor or a fluid-driving rotor

The invention relates to a fluid-driven or fluid-driving rotor, with at least two identical, running helically around the rotor axis of rotation and arranged at equal distances from one another on a hub Blades / their beginnings in a first plane perpendicular to the rotor axis of rotation and their ends in a second the plane perpendicular to the rotor axis of rotation and their outer longitudinal edges taper to a point.

Rotors of this type are used for various purposes. For example, the rotors that drive a fluid become propulsion of vehicles, for stirring or mixing liquids or gases - in the case of mixing can also granular, solid materials are added - for homogenizing liquids containing loosely agglomerated materials, such as liquid manure, for venting or gassing liquids, for atomizing liquids, for pumping

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of liquids or liquid mixtures containing solids, etc. are used.

A propeller is generally used for these purposes, in which the blades fastened on a hub in the cylindrical ones lying concentrically with the axis of rotation of the propeller Cross-sectional planes have more or less streamlined profiles. The propulsion of the fluid is thereby caused by a circulation that arises around such a streamlined profile, as on one side the Fluid flows at a higher speed from beginning to end, than on the other side.

However, snails have also been proposed for the purposes mentioned above. However, these could be in the Not enforced in practice due to insufficient efficiency, although various modifications have been proposed are. For example, screws with changing pitch angles of the blades and screws with perpendicular to the axis of rotation, more or less curved blade cross-sections, in which the blades are bent forward or backward have been proposed, as well as screws with variable diameter hubs. But it has none of these Modifications proven in practice.

The invention is now based on the object of this drawback to remedy.

According to the invention, this object is achieved in the case of a fluid-driving device The rotor is solved in that the blade length (L) measured along the outer longitudinal edge is at least equal to the 1 1/2 times the maximum blade height and that is the ratio between the blade height H and the mutual distance of the blades (s χ sinßHm range from about 0.5 to

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about 2.5 and the pitch angle β of the blades is approximately in the range from 20 to 55.

In the rotor according to the invention it has been found that the fluid in the form of vortices extending in the longitudinal direction of the axis of rotation of the rotor between the blades flows backwards, with a high degree of efficiency in terms of driving the fluid is ensured.

In the case of a rotor driven by a fluid, this object is achieved according to the invention in that the along the outer The blade length L measured along the longitudinal edge of the blades is at least equal to 1 1/2 times the maximum blade height H and that the ratio between the maximum blade height H and the mutual spacing of the blades S χ sinß in the range from about 0.5 to 2.5 and the pitch angle ß of the blades in the range from about 5 ° to 20 °.

In both cases, the relative inflow angle of the fluid is

in relation to the outer longitudinal edge of the blades approx. 5 to, "o

Further advantages, details and features of the invention emerge from the following, with reference to the enclosed Drawing following description of several exemplary embodiments. In the drawing show:

Figure 1 schematically shows the development of a section of a rotor according to the invention with rectangular blades,

Figure 2 is a side view of a first embodiment of a rotor according to the invention,

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Figure 3 shows a section through the embodiment according to Fig. 2 along the line III-III of Fig. 2,

Figure 4 shows the development of a blade in the
Fig. 2 and 3 shown rotor,

FIG. 5 development images of further blade designs in a rotor according to the invention,

FIG. 6 cross sections of rotor blades in a plane perpendicular to the axis of rotation of the rotor,

FIG. 7 shows an embodiment of a rotor according to the invention, which is particularly suitable for driving
of a ship,

FIG. 8 a device for mixing liquids with a rotor according to the invention,

FIG. 9 shows a liquid suitable for homogenizing suspended solids
Arrangement with a rotor according to the invention,

FIG. 10 shows a device for mixing liquids and gases with a rotor according to the invention,

Figure 11 shows an embodiment of an inventive Rotors for use as a wind or water mill and

FIG. 12 shows a further embodiment of a rotor according to of the invention for use as a wind or water mill.

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ORIGINAL INSPECTED

The extremely simple shape of the rotor according to the invention is due to the fact that very short (non-slender) rotor blades with a sharp edge are used, the wind around the rotor hub with a constant pitch angle. All cross-sections of a rotor blade are in the planes perpendicular to the hub are symmetrical, which means that the blades in these planes are not forward or are inclined or curved backwards.

Fig. 1 shows schematically the development of such a rotor with a hub 1 and some arranged on this hub, rectangular blades 2 in the embodiment shown. The hub has a diameter d and the outer edges 3 of the blades 2 lie on a diameter D.

In the embodiment of a rotor shown schematically in FIG. 1, it can be seen that on the leeward side at the outer edge 3 each blade a strong, stable vortex 4 as a result of the dissolving along the pointed edge 3 of the blade and Fluid mass hitting this blade. This fluid mass has a relative velocity U with respect to the blade 2, which results from the peripheral speed WD of the blade edge and the axial velocity V of the fluid with respect to the rotor. The diagonally to the Fluid mass reaching the windward side of the shovel receives a backward impulse from this shovel and executes the For the most part there is a rollover over the edge of the blade, whereupon a vortex 4 forms on the leeward side. This Vortex, which begins near the front end of the blade when viewed in the direction of flow of the fluid, increases in the rearward direction steadily increasing in size and strength, since along the entire outer edge 3 further, overlapping fluid mass is added to the fluid mass present in the vortex. The average flow velocity in the longitudinal direction of the growing eddy, which is more or less the shape of a cor-

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ORiGfNAL INSPECTED

kenziehers assumes, also increases from the front end to the rear end of the blades, since the negative pressure in the Core of the vortex running in this direction as a result of the increasing centrifugal effect in the expanding vortex gets bigger.

Between the blades of the rotor, conical, corkscrew-shaped vortices and their speed are formed is getting faster and faster and along the entire length of the rotor fluid from the outside between the blades of the rotor and suck this fluid in relation to the rotor during the displacement of the fluid by means of the rotor Give backward speed.

In this way, the sucked fluid is not just kinetic Energy is given in the direction of the rotor axis of rotation, but it also arises on the windward side of each blade Positive pressure and a negative pressure on the leeward side, creating both a feed force in the axial direction and a Torque can be exerted on the rotor axis.

It has now been shown that these effects are only clean occur over the entire length of the blades and thus an optimal effect of the rotor only results when the blade cross-section has a certain shape and certain Relationships between the blade length L and the greatest height FI of the blades and the blade spacing S χ sinß, where ß is the pitch angle of the blades and a certain ratio between the peripheral speed O? χ D and the relative speed V of the fluid occurring in the axis in the direction of the rotor with respect to the rotor are observed will.

The blades should primarily taper to a point on the outer circumference of the rotor in order to ensure a sufficiently stable effect.

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at to generate. Furthermore, along the outer circumference of the Blade length L measured at least 1 1/2 times the greatest blade height H, so that sufficiently strong, corkscrew-shaped vortices can be generated. Besides that the blade height H should not be too much of the perpendicular blade spacing S χ sinß differ. If the distance between the blades is chosen too small, the training will be impaired by eddies between the blades, while if the distance is too great compared to the fluid mass present between the blades, relatively little fluid mass

/ una drawn into the corkscrew-shaped vortex is accelerated.

In order to ensure optimal performance of the rotor according to the invention, should therefore be the ratio between the blade height H and the distance between the blades S χ sinß preferably are between 0.5 and 2.5.

The blade length must not be too small, but also not too large, as otherwise each blade will die in the relative flow direction partially shields the next following blade. This of course depends on the distance between the blades, the pitch angle the blades and the relative inflow direction together. It can theoretically be shown that the maximum Efficiency with feed rotors, i.e. rotors that move the fluid, with the pitch angle ß of the blades increases and is almost optimal when the slope angle is about 45 °. Therefore, the pitch angles of feed rotors should between approx. 20 and approx. 55, with smaller pitch angles of up to 35 in the case of rapidly rotating rotors, e.g. for screws for outboard motors, while the larger pitch angles of about 30 ° in the case of rotors rotating relatively slowly, such as B. in ship propellers, are provided.

Furthermore, the relationship between shear force (pressure) and

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ORIGINAL INSPECTED

" ¹² " 2 9 / Λ 6 1 3

Longitudinal force (friction) with increasing relative inflow angle i in relation to the outer edge of the blade, i.e. the pitch angle ß of the blade minus the angle ^ χ e, at each blade as a function of the speed V and the speed ω χ D from (see Fig. 1). This angle of inflow must therefore only be about 5 to 10 in order to achieve an optimal effect in a rotor for moving a fluid.

With the aforementioned optimal values of the pitch angle, the relative inflow angle and the ratio between the blade height and the distance between the blades results in the measured along the outer edge of the blade Blade length L about 1.5 to 6 χ as large as the largest blade height H for propellers and similar rotor types with a sufficiently high feed efficiency.

When using a rotor driven by a fluid, e.g. when using the rotor as a windmill, theoretically show that the power efficiency increases with decreasing pitch angle ß of the blades and almost is optimal at a slope angle of about 10. The pitch angle ß for windmills or the like. is therefore between 5 and 20, with the larger pitch angle of 10 to 20 for slowly turning rotors, e.g. when driving pumps and the like, and the smaller pitch angle of 5 to 10 ° for high-speed rotors, e.g. for driving power generators, is used.

If of the aforementioned optimal values of the pitch angle, the relative inflow angle and the ratio between the blade height and the distance between the blades is assumed in the case of the one in question Fluid driven rotors which are measured along the outer edge

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ORIGINAL INSPECTED

Its blade length L is about 4 to 12 times as large as the largest Blade height must be H in order to be able to achieve a sufficiently high performance.

Figures 2 and 3 show an embodiment of the rotor according to the invention, which is used to drive a fluid, for example in the case of a ship's propeller. The rotor has a hub 5 on which a number of blades 6 helically is appropriate. Fig. 4 shows that the blade in the developed state can more or less have the shape of a rectangular triangle, the side 7 of which with the Hub 5 is the edge of the blade to be connected and the side 8 of which forms the outer longitudinal edge of the blade.

The outer edge 8 of the blade can run in a straight line, with the blade can overall have a rectangular shape, or wave-shaped or otherwise curved in a suitable manner run, as is shown by way of example in FIG. 5. From Fig. 5 it can be seen that the blades in the unwound State a rectangular, a triangular or an arrow-shaped or wave-like shape. In FIG. 6, possible cross-sections of the blades are shown with full or dashed lines shown in a plane perpendicular to the rotor axis of rotation. In this context it should be emphasized that the outer edge the shovel tapers to a point and is thus, for example, knife-shaped or Gothic, while the to the Hub adjacent blade root can be rectangular or more or less rounded.

As stated above, during operation, when the rotor rotates in the direction of arrow A, between successive blades a vortex 4 is generated in which the flow has the direction of the arrow in this vortex. The direction of flow of the fluid in relation to the rotor is indicated by arrow B In this context, it should be noted that

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INSPECTED

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it is generally necessary to provide the rotor with at least two blades.

The use of the blade shapes shown, in which the height of the blades increases from 0 to a certain value, has the advantage, among other things, that inflow losses and the sticking of dirt and the like present in the fluid to the blades are avoided.

Fig. 7 shows a further embodiment of a rotor with rectangular blades which, similar to the embodiment according to FIGS. 2 and 3, are particularly suitable for use as Suitable for a ship's propeller or for stirring liquids.

It has been shown that, when the rotor is used as a feed member of a ship, even when the rotor rotates a high level of effectiveness is achieved in the opposite direction to the braking of the ship,

8 shows the arrangement of a rotor according to the invention in a stepped housing which has two sections 9 and 10 of round cross-section. On the front section 9 A feed line 11 is connected with a smaller diameter and a feed line 12 is connected to the section 10 with a larger diameter. A specific liquid can be supplied through each of the lines 11 and 12. If during feeding As the liquid rotates the rotor, these liquids become effective with one another due to the vortex generated by the rotor mixed, so that on the exit side of section 10 in the direction of arrow C a homogeneous mixture of both Liquids are dispensed.

Fig. 9 shows a construction with a rotor according to the invention, which is particularly suitable for homogenizing liquids with solids in them. From Fig. 9

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ORIGINAL INSPECTED

" ¹⁵ " 292 ^ 13

it can be seen that the rotor is in one in an intermediate wall existing opening 14 is attached, the diameter of which in the intended flow direction of the arrows D gradually decreases, so that near the rear of the rotor between the outer circumference of the rotor / its diameter in the flow direction of arrow C gradually increases, and the inner circumference of the opening a relatively small slot is present is.

The construction shown in Figure 10 is particularly useful to. Mixing air or gas into a liquid. From Fig. 10 shows that the blades 6 are mounted on a hollow shaft or a hollow hub 5 in this construction.

The interior 15 of the hollow shaft 5, which is for the supply of air or gas can be used in the direction of arrow D, is through holes 16 provided in the blades at the level of the Rotor in connection with the environment. The bores 16 can extend axially (see FIG. 10) and / or radially. It can but also 6 holes in the hub between the blades 17 may be provided.

The air and / or the gas can pass through the hollow shaft during operation supplied under pressure or sucked in by the negative pressure generated in the shaft during operation. When turning the The vortices created by the rotor in the liquid result in an effective mixture of gas and air.

The rotor can easily contain the liquid in one containing bucket or the like. to be ordered. Possibly For example, the rotor can be surrounded by a kind of Venturi tube 18, which is also accommodated in the space containing the liquid is. The rear side of the rotor, seen in the direction of advance of the liquid, lies at the level of the smallest cross section of the Venturi tube according to FIG. 10. It is also possible to use the

ORlG (MAL INSPECTED

Liquid through a line 19 to a hub or the shaft surrounding and connected to one end of the Venturi tube 18 Feed housing 20, as indicated by dashed lines in Fig. 10, instead of the rotor directly to be arranged in a space containing the liquid.

FIG. 11 shows the application of the invention to a wind or water mill. In this embodiment, the blades 6 are attached to a hub 5 which is arranged between a streamlined head 21 located in front of the hub 5 and a downstream body 22 located behind the hub 5, which is connected to a support 23. In this embodiment as a windmill or water mill, the greatest height of a blade 6 is preferably about 1/7 of the outer diameter of the hub 5. In the case of a hub with a streamlined head on the upstream side, a layer thickness of about 1/7 of the hub diameter occurs around the hub in particular high speeds, so that the kinetic energy of the inflowing fluid is concentrated in this layer adjacent to the hub, from which this energy can be extracted with high efficiency. The fluid flows in the direction of the arrows in FIG. 11 onto the rotor and is guided by the flow line head 21 onto the outer circumference of the hub 5. The flowing fluid drives the hub with it. the blades attached thereto, the flow effect explained above occurring. The hub can, for example, with an electric motor or the like. be coupled to deliver energy.

Even with such a wind or water mill, instead of blades with gradually increasing height, as shown in Fig. 11 is shown, blades with a rectangular shape in the developed state can be used, as shown in Fig.12.

Of course, the arrangement of the rotor must be made in such a way that the fluid is sufficiently

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ORIGINAL INSPECTED

dialer direction can flow to the necessary eddies to achieve.

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. ORIGINAL INSPECTED

Claims (17)

PATENT LAWYERS
Dr. TCt. nat. DiETSit LOUiS Wpi-Phya. CL / -. US? 'ÖHL / VJ Diploma! FRANZ LOi-Tr-ZNTZ NORNSBRq KKSlSPPATZ Ϊ 19 705/6 40 / Ko Nederlandse Organization voor Toegepast Natuurwetenschappelijk Onderzoek ten behoeve van Nijverheid, Handel en Verkeer (Nijverheidsorganisatie TNO), Bankaplein 1, The Hague, The Netherlands A fluid-driven rotor or a fluid-driving rotor Expectations A fluid-driven rotor with at least two identical, helical lines around the rotor axis of rotation extending and at equal distances from one another on a hub arranged blades / their Starts in a first plane perpendicular to the rotor axis of rotation and its ends in a second plane to the rotor axis of rotation vertical plane and the outer longitudinal edges of which taper to a point, characterized in that the blade length (L) measured along the outer longitudinal edge (3) is at least equal to 1 1/2 times the maximum Blade height is and that the ratio between the blade height (H) and the mutual spacing of the blades (3) (S χ sinß) in the range of approximately 0.5 to approximately 2.5 and the pitch angle (β) of the blades (3) is approximately in the range from 20 ° to 55. 2/0740 2. Rotor according to claim 1, characterized in that the pitch angle (ß) for high-speed rotors is between 20 and 35. 3. Rotor according to claim 1, characterized in that the pitch angle (ß) for slowly running rotors is between 30 and 55. 4. Rotor according to one of claims 1 to 3, characterized in that that the blade length (L) measured along the outer longitudinal edge (3) of the blades (2) in The range is between almost 1 1/2 times and 6 times the maximum blade height (H). 5. Rotor according to one of claims 1 to 4, characterized in that that the rotor hub (5) is hollow and the cavity of the hubs with the outer circumference of the rotor in Connection is (see, for example, Fig. 10). 6. Rotor according to claim 5, characterized in that substantially axially extending passages are provided in the blades (6), the abe the cavity of the ^N (5) connected to the outer circumference of the rotor. 7. Rotor according to claim 5 or 6, characterized in that in the blades (6) extending almost radially Passages (16) are provided which connect the cavity of the hub (5) to the outer circumference of the rotor. 8. Rotor according to one of claims 5 to 7, characterized in that that between the blades (6) in the hub (5) passages (17) are provided which form the cavity connect the hub to the outer circumference of the rotor. 909882/0740 9. A fluid-driving rotor with at least two identical, running helically around the rotor axis of rotation and at equal distances from one another a hub arranged blades whose beginnings in a first plane perpendicular to the rotor axis of rotation and the ends of which lie in a second plane perpendicular to the axis of rotation of the rotor and their outer longitudinal edges tapered to a point, characterized in that the measured along the outer longitudinal edge (3) of the blades (2) Blade length (L) is at least 1 1/2 times the maximum blade height (H) and that the ratio between the maximum blade height (H) and the mutual spacing of the blades (2) (S χ sinß) in the area from about 0.5 to 2.5 and the pitch angle (β) of the blades (2) in the range from about 5 to 20. 10. Rotor according to claim 9, characterized in that the pitch angle (ß) between slowly running rotors 10 and 20 lies. 11. Rotor according to claim 9, characterized in that the pitch angle (ß) between high-speed rotors 5 and 10 lies. 12. Rotor according to one of claims 9 to 11, characterized in that that the blade length (L) measured along the outer edge (3) of the blades (2) 1.5 to 12 times as large as the maximum blade height (H). 13. Rotor according to one of the preceding claims, characterized characterized in that the maximum height of the blade (2) is about 1/7 of the diameter (d) of the hub (5) of the rotor is. 909882/0740 14. Rotor according to one of the preceding claims, characterized in that the measured in the radial direction Height of the blades (2) between the outer longitudinal edge (3) of the blades and the hub (5) from the beginning remains the same until the ends of the show. 15. Rotor according to one of claims 1 to 13, characterized in that that the height of the blades (6) measured in the radial direction between the outer longitudinal edge of the blades and the rotor hub gradually increases or decreases from the beginnings to the ends of the blades. 16. Rotor according to claim 15, characterized in that the Blade height gradually increases or decreases in a wave-like manner (see FIG. 5). 17. Rotor according to one of the preceding claims, characterized in that the front and / or rear sections the blades can be inclined both forwards and backwards. 909882/0740