Note: Descriptions are shown in the official language in which they were submitted.
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English Translation of International Patent Application
PC~/EP 91~01761
91-0664 ~a/ki
Josef Moser
8058 Pretzen
R O ~ O R
This invention relates to a
rotor for absorbing energy from a flowing fluid and
for delivering energy to a flowing fluid, which rotor
consists of a hub and at least one rotor blade.
Such rotors are widely used
in technology. For instance~ energy is absorbed from
a flowing fluid by windmills, by which the energy of
the approaching wind is converted to rotational energy,
which is converted by a generator to electric power.
~he ener~y of flowing water is converted to rotational
energy, e~g., by Kapla~ turbines. Finally, gas turbines
are known, which comprise a large number of blades, by
which the energ~ of an expanding gas stream is converted
to rotational energy.
On the other hand, rotors are
also used to deliver energy to a flowi~g fluid. This is
effected, e.g., in order to drive a vehicle. Examples
are constituted by a marine screw propeller and a pro-
peller of an aircraft. Another function of rotoxs for
delivering energy to a flowing fluid is to mix the
fluid. In that case the rotors constitute so-ca~ed
stirring members.
........... ~. . . ~......... .. ........
In all fields mentioned above it has
been endeavored for a long time to improve the effect-
iveness of the rotor by an appropriate shape thereof.
It is an object of the present invention
so to improve a rotor which is of the kind described
first hereinbefore that the efficiency of the rotor is
improved further, whether the ro-tor is used to absorb
energy from a flowing fluid or to deliver energy to a
flowing fluid.
In accordance with the invention that
obaect is accomplished by the characte~zing part of
claim 1. In accordance therewith the at least one rotor
blade comprises at least one aerodynamic and/or hydrodyna-
mic wave, which defines two edges with the planar portion
of the rotor blade in such a manner that the edge which
is approached by the radial flow is inclined by an
angle ~ from the normal on the edges of the rotor
blade in such a manner that said edge extends outwardly
from that rotor blade edge which leads in the direction
of rotation whereas the other edge is at right angles
to the rotor blade edges.
The increase o~he ef~iciency of the
rotor in accordance with the invention can physically
be explained as follows: For that purpose the energy-
producing systems, on the one hand, and the energy-
delivering systems, on the other hand, must be con-
sidered. The energy-producing systems include 9 e.g~,
the wind turbines. The energy-delivering systems include,
e.g., the marine scre~ propeller and the air-impelling
2~o'~3~
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propeller. In the energy-absorbing systems the air
flowing off outwardly over the rotor blade or the
water which owing to the centrifugal force acting
on the fluid elements flows off out~ardly, will
impinge on the obstacles which are constituted by
the waves. Because the leading edge of the wave is
properly inclined, a part of the radial flow of the
fluid will flow o~f alo~g that edge and will thus pro-
duce an additional driving component. The rotor de-
signed in accordance with the present invention will
give rise -to favorable pressure conditions, i.e.,
appropriate regions of superatmospheric and subatm~s-
pheric pressure, which can additionally be converted
to a driving moveme~t in a favorable manner. In the
energy-delivering systems the obstacles which are
constituted by the waves are effective in -that they
virtually concentrate the flow. This can be under-stood
in that the radiall~ outwardly directed component of
the flow is now prevented from simply flowing off and
is deflected for reasons of continuity to axial and
tangential directions. As a result, particularly the
axial compo~ent is strengthened in a manner which con-
firms the presence of an invention and the efficiency
is thus improved too. The surface area which is con-
tacted b~ the approaching fluid and the area which is
in contact with the ambient fluid are increased by
about 1~/~ whereas the total flow area is not increased
at the same time.
A particularly desirable xesult produced
by the present invention resides in that the cavitation
produced by rotors rotating in liquid fluids is st~ngly
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reduced and may be entirely prevented. In rotors
rotating in gaseous fluids the often disturbing gene-
ration of noise can also substantially be reduced. In
that case the breakdown of the flow at the blade edge
will take place at much higher rotational velocities
than at rotors which do not have the aerodynamic and/or hy-
drodynamic waves provided in accordance with the invention.
According to a desirable feature of
the prese~t invention the aerodynamic and/or hydrodyna-
mic waves and the remaining rotor blade are additionally
provided with flutes. Such flutes may prope~y be shaped
in dependence on the purpose of the rotor. For instance,
in case of a gas flow they may be relatively fine whereas
in a water flow they will be correspondingly coarser.
In dependence on the velocity of flow it may be desirable
to ~Nide coarser flutes also in a gas flow.
Another desirable feature of the in-
vention resides in that a radially inwardly disposed
~ortion of the rotor blade remains flat whereas the rotor
blade is provided on an outer portion with the aerodyna-
mic and/or hydrodynamic shafts provided in accordanGe
with the invention. In that c~se the fact is taken into
account that strong centrifugal forces will be effective
only a~ the radius increases and will not occur in the
radially inner region of the rotor blade.
Preferred uses of the rotor in accord-
ance with the invention will become apparent from the
further dependent claims.
Further details and adva~tages of the
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invention will be explained hereinafter with refer-
ence to the illustrative embodiments shown in the
drawing, in which
: Figure 1 is a schematic perspective
view showing a part of a rotor blade in accordance
with the invention,
Figure 2 is a sectional view taken
on line A-A in Figure 1,
Figure 3 is a perspective view showing
a portion of a rotor arm in accordance with the i~ven-
tion,
Figure 4 is a side elevation showing a
rotor arm in accordance with the invention,
Figure 5 sho~.qs a first embodiment of a
wind energy converter, in which the rotor in accordance
with the,~nvention is used,
Figure 6 shows a second embodiment of
a wind energy converter, in which a rotor in accordance
with the invention is used7
Figure 7 is a perspective view showing
a part of a rotor,in accordance with the invention
which constitutes a helicopter rotor7
Figure 8 is a perspective view showing
a marine screw propeller, which embodies the rotor in
accor~nce with the invention,
F~re 9 is a perspective view ~Dwing
a Kaplan turbine, which embodies the rotor in accor~
ance with the invention~
Figure 10 is an elevation showin~ a
detail of Figure 9,
Figure lla and llb are a front ele-
vation and side elevation, respectively, ~hi~h show a
fanwheel, which embodies the rotor in accordance with
the invention,
~ igure 12 shows a compressor wheel of a
turbocharger, which embodies the rotor in accordance
with the invention and
Figure 13 shows the end stage blades
which are provided in a condensing turbine and em~ody
the present invention.
The improved basic mode of operation of
the rotor in accordance with the invention can be ex-
plained with reference to Figure l. The rotor blade 10,
which is shown here only in part, is substantially
planar. A wave 12 protrudes from the plane and defines
two edges 14 and 15. Thatwave is described also as an
aerodynamic and/or hydrodynamic wave 12, in order
to avoid misunderstanding. The rotor blade which is
shown here in part rotates in a tangential direction,
which is indicated here by the arrow B. The velocity
of flow of the fluid which surrounds t..e ro-tor ~lade 1
can be resolved into three velocity Or flow components
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in radial, tangential and axial directions. The ~ow
in the radial direction proceeds in the direction of
the arrow A from the inner p~rt of the rotor blade to
the ou~er end, not shown here, of the rotor blade.
~he tangential direction of flow is again indicated
by the arrow B. ~he axial direction of flow is at
right angles to the paper plane.
The edge 14 of the rotor blade 10
is inclined by the angleC~ from the normals 20 on the
edges 22, 24 of the rotor hlade. On the other hand,
the edge 16 defined by the aerodynamic and/or hydrodynamic
wave and the planar rotor blade extends at right angles
to the edges 22 and 24 of the ro~ r blade. AS soon as
the fluid which flows radially outwardly as indicated
by the arrow A impinges on the obstacle which is consti-
tuted by the wave 12, the fluid is deflected in part
into the direction of the arrow a so that an additional
componen-t of driving force is exerted on the rotor. ~he
undeflected remaining part of the flow flows in the
direction of the arrow b over the wave and then con-
tinues to flow radially over the blade in the directio~
of the arrow c until said flow possibly impinges on the
next wave.
Figure 2 is a transverse sectional
view showing a rotor blade 10. In the embodiment shown
in Figure 3 the aerodynamic and/or hydrodynamic waves
12 are close to each other. In Figure 4 the inner por-
tion of the rotor blade is smooth and in the outer
portion of the rotor blade the waves 12 are close to
each other.
Figures 5 and 6 show two horizontal
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windmills, which comprise the rotor which is in
accordance with the invention and comprises rotor
blades 10. The hub of the rotor is designated ll.
The horizontal windmill 30 comprises two s~mmetri-
cally arranged rotor blades lO. The hor~ontal wind-
mill 35 shown in Figure 6 is a symmetrical and its
hub 11 is disposed at the center of gravity of the
asymme-trical rotor blade 10. Figure 7 shows a de~il
of a helicopter rotor 40, more specificall~, a blade
10 of a helicopter rotor, and the radially inner par-t
13 has a conventional smooth profile whereas the radi-
all~ outer portion is formed in accordance with the
present invention with aerodynamic waves 12.
Figure 8 shows a marine screw pro-
peller that comprises four rotor blades designed in
accordance with the invention. It will be under-stood
that the marine screw propellers may have an desired
other number of blades. But it is important that all
said blades comprise the waves 12 in accordance with
the present invention. Said blades might also be
planar in their radiall~ inner portion; this is not
shown here in detail. The outer contour of the blade
shape of the marine screw propeller 50 and of the
other rotors mentioned here b~ wa~ of example is not
changed again as such.
Figure 9 shows a Kaplan turbine 60,
which in accordance with the invention is formed with
waves 12 in its rotor blades lO. ~he hub is des~nated
ll. Figure 10 shows a detail of one of the rotor
blades lO of the Eaplan turbine 60.
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~ igures lla and llb show a fan 70,
which comprises six rotor blades 10 provided with the
shafts 12 in accordance with the invention. ~he fan
70 also comprises a stabilizer ring 72.
Figure 12 shows a compressor wheel 80
of a turbocharger~ The rotor blades 10 of that wheel
comprise waves 12 in accordance with flutes 26, which
are indicated by the fine lines in Figure 12.
~ igure 13 shows rotor blades 10 consisting
of the end stage blades of a condensing turbine. Said
blades are provided o~ a hub 11. In that case too
there are fine flu-tes 26 beside the wave in addition
to the waves 12.
In analogy to the illustrative embodiments
shown here, rotors for gas turbine blades, other steam
turbines as well as rotors for engine blades for jet
engines of jet-propelled aircraft etc. may be designed
to increase their efficiency.
