U.S. patent application number 12/155014 was filed with the patent office on 2008-12-04 for blade of a fluid-flow machine featuring a multi-profile design.
Invention is credited to Volker Guemmer.
Application Number | 20080298974 12/155014 |
Document ID | / |
Family ID | 39577290 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080298974 |
Kind Code |
A1 |
Guemmer; Volker |
December 4, 2008 |
Blade of a fluid-flow machine featuring a multi-profile design
Abstract
A blade of a fluid-flow machine has a cross-section, which in at
least one part of the blade height in at least one flow-line
profile section is formed by at least two partial profiles
separated from each other, with each of the individual partial
profiles having the shape of a blade profile.
Inventors: |
Guemmer; Volker; (Mahlow,
DE) |
Correspondence
Address: |
Harbin Klima Law Group PLLC
500 Ninth Street SE
Washington
DC
20003
US
|
Family ID: |
39577290 |
Appl. No.: |
12/155014 |
Filed: |
May 29, 2008 |
Current U.S.
Class: |
416/223R |
Current CPC
Class: |
F04D 29/324
20130101 |
Class at
Publication: |
416/223.R |
International
Class: |
F01D 5/14 20060101
F01D005/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 29, 2007 |
DE |
10 2007 024 840.9 |
Claims
1. A blade of a fluid-flow machine, the blade having a
cross-section, which in at least one part of a blade height in at
least one flow-line profile section is formed by at least two
partial profiles separated from each other, with each of the
individual partial profiles having a shape of a blade profile.
2. The blade of claim 1, with the at least two partial profiles
including a fore-profile and at least one aft-profile of different
relative maximum thickness.
3. The blade of claim 2, with one aft-profile having a relative
maximum thickness larger by at least 30 percent than the
fore-profile.
4. The blade of claim 1, with the at least two partial profiles
including a fore-profile and at least one aft-profile of equal
relative maximum thickness.
5. The blade of claim 1, with the at least two partial profiles
including a fore-profile and at least one aft-profile of equal
absolute maximum thickness.
6. The blade of claim 1, with at least one zone of the blade having
a multi-profile design being positioned in a center area of the
blade height.
7. The blade of claim 1, with at least one zone of the blade having
a multi-profile design being positioned on at least one fixed blade
end, confined by a blade root/shroud.
8. The blade of claim 7, with at least one zone of the blade having
a multi-profile design being positioned on at least one free blade
end with a radial gap towards a hub/casing contour.
9. The blade of claim 1, with the multi-profile design being
arranged essentially in a meridional flow direction.
10. The blade of claim 1, with the multi-profile design having an
inclination in a direction of one blade end.
11. The blade of claim 1, with a gap between two partial profiles
defining a contracting flow path, as viewed in a blade height
direction.
12. The blade of claim 1, with a trailing edge of a fore profile
being arranged in a trailing edge and rim-near zone (TRZ), with the
trailing edge-near zone being defined as a portion of the blade
between 40 percent and 100 percent of a meridional blade chord
length (Cm), and the rim-near zone being defined as blade portions
between 0 percent and 40 percent as well as between 60 percent and
100 percent of a blade height/annulus width.
13. The blade of claim 2, with at least one zone of the blade
having a multi-profile design being positioned in a center area of
the blade height.
14. The blade of claim 2, with at least one zone of the blade
having a multi-profile design being positioned on at least one
fixed blade end, confined by a blade root/shroud.
15. The blade of claim 2, with at least one zone of the blade
having a multi-profile design being positioned on at least one free
blade end with a radial gap towards a hub/casing contour.
16. The blade of claim 2, with the multi-profile design being
arranged essentially in a meridional flow direction.
17. The blade of claim 2, with the multi-profile design having an
inclination in a direction of one blade end.
18. The blade of claim 2, with a gap between two partial profiles
defining a contracting flow path, as viewed in a blade height
direction.
19. The blade of claim 2, with a trailing edge of a fore profile
being arranged in a trailing edge and rim-near zone (TRZ), with the
trailing edge-near zone being defined as a portion of the blade
between 40 percent and 100 percent of a meridional blade chord
length (Cm), and the rim-near zone being defined as blade portions
between 0 percent and 40 percent as well as between 60 percent and
100 percent of a blade height/annulus width.
Description
[0001] This application claims priority to German Patent
Application DE 102007024840.9 filed May 29, 2007, the entirety of
which is incorporated by reference herein.
[0002] The present invention relates to blades of fluid-flow
machines, such as blowers, compressors, pumps and fans of the
axial, semi-axial and radial type using gaseous or liquid working
media. The fluid-flow machine may include one or several stages,
each having a rotor and a stator. In individual cases, the stage
can have only a rotor. The rotor includes a number of blades, which
are connected to the rotating shaft of the machine and transfer
energy to the working medium. The rotor may be designed with or
without a shroud at the outer blade ends. The stator includes a
number of stationary blades, which may either feature a fixed or a
free blade end on the hub and on the casing side. Rotor drum and
blading are usually enclosed by a casing; in other cases (e.g.
aircraft or ship propellers) no such casing exists. The machine may
also feature a stator, a so-called inlet guide vane assembly,
upstream of the first rotor. Departing from the stationary
fixation, at least one stator or inlet guide vane assembly may be
rotatably borne, to change the angle of attack. Variation is
accomplished for example via a spindle accessible from outside of
the annulus. In an alternative configuration, multi-stage types of
said fluid-flow machines may have two counter-rotating shafts, with
the direction of rotation of the rotor blade rows alternating
between stages. Here, no stators exist between subsequent rotors.
Finally, the fluid-flow machine may--alternatively--feature a
bypass configuration such that the single-flow annulus divides into
two concentric annuli behind a certain blade row, with each of
these annuli housing at least one further blade row. FIG. 2 shows
examples of four possible configurations of fluid-flow machines,
where a casing 1, a hub/rotor drum 2, a machine axis 3 and an
annulus 9 are indicated in each view, along with the blade
configurations.
[0003] The fluid flow in the blade rows of aerodynamically highly
loaded fluid-flow machines is characterized by the very high degree
of re-direction to be attained. The required re-direction of the
fluid flow can be so extreme, either in parts of the blade height
or along the entire blade height, that premature separation of the
boundary layer flow on the blade profile and in the side-wall area
on the hub and casing will occur with conventionally designed
state-of-the-art blade profile sections. Conventional blades
without additional design features for stabilising the profile and
wall boundary layers, as shown in FIG. 1, are unsuitable due to the
occurrence of extremely high pressure losses and the inability to
attain the flow re-direction required. Moreover, the secondary
flows occurring in the area of the confining side walls (on hub and
casing) will be uncontrollable, resulting in further, very high
total pressure losses. In consequence, the fluid-flow machine will
have a generally bad performance as regards efficiency and the
stability margin available.
[0004] Blade rows with a profile design according to the state of
the art, see FIG. 1, have too small an operating range and too high
losses to attain the operating characteristics required for modern
fluid-flow machines, this being due to the high aerodynamic loading
of the boundary layers, i.e. the two-dimensional boundary layers on
the profile and the three-dimensional boundary layers on hub and
casing walls.
[0005] In a broad aspect, the present invention provides for a
blade of a fluid-flow machine which is characterized by improved
efficiency.
[0006] The present invention provides for a blade for application
in a fluid-flow machine which, in at least one part of the annulus
width (or the blade height, respectively) in at least one flow-line
section, is formed by at least two separate profiles, each of which
featuring essentially the shape of a blade profile with a rounded
nose (leading edge).
[0007] The present invention is more fully described in light of
the accompanying drawings showing preferred embodiments. In the
drawings,
[0008] FIG. 1 is a schematic representation of a blade according to
the state of the art,
[0009] FIG. 2 shows possible configurations of fluid-flow machines
relevant to the present invention,
[0010] FIG. 3 shows an example of a blade according to the present
invention in schematic representation,
[0011] FIG. 4 shows further examples of blades according to the
present invention in meridional view,
[0012] FIG. 5 provides a definition of meridional flow lines and
flow-line profile sections,
[0013] FIG. 6a shows a multi-profile design according to the
present invention, as viewed in a flow-line profile section,
[0014] FIG. 6b shows further types of multi-profile design, as
viewed in a flow-line profile section,
[0015] FIG. 7a shows examples of a multi-profile design in the
center area of a blade, three-dimensional view,
[0016] FIG. 7b shows examples of a multi-profile design at the
fixed blade end, three-dimensional view,
[0017] FIG. 7c shows examples of a multi-profile design at the free
blade end, three-dimensional view,
[0018] FIG. 8 provides a definition of zones for particularly
favorable positioning of the fore-profile trailing edge according
to the present invention.
[0019] As shown in FIG. 1, according to the state of the art, a
conventional blade 6, has a leading edge 7, a trailing edge 8, a
pressure side 5 and a suction side 4, is positioned between a
casing 1 and a hub/rotor drum 2, and features no subdivision into
several, successive profiles over a selected part of the blade
height. Known are only so-called tandem configurations, in which
re-direction is accomplished via two physically separate blade
rows. FIG. 1 shows a profile section of the blade on the right of
the meridional section shown on the left. In the meridional
section, flow takes place from the left to the right, as indicated
by the bold arrow. A machine axis 3 is also shown in the meridional
section. On conventional blades, flow around the individual profile
sections of the blades (see profile section P-P) takes place
separately from the leading edge onward, without fluid
communication between the blade sides.
[0020] FIG. 3 shows one embodiment of a blade 6 according to the
present invention. Here again, the blade is shown in meridional
section on the left, with flow taking place from the left
(left-hand side of the illustration). Profile section P-P (taken
along section line P-P from the meridional view) is shown on the
right in FIG. 3. The blade 6 of the present invention also includes
a leading edge 7, a trailing edge 8, a pressure side 5 and a
suction side 4, and is positioned between a casing 1 and a
hub/rotor drum 2. The blade 6 also has a plurality of passages 10
between the pressure side 5 and the suction side 4 that create
several sub-divisions of the profile (see especially the profile
section P-P on the right), each featuring different length and
shape in the direction of the blade height and being arranged in a
selected partial area of the blade height (annulus width). In the
section P-P shown on the right, it can be seen how adding the
passages 10 to the blade 6 has, in effect, created three separate
airfoils on the single blade 6 at that section P-P. Deviating from
the representation here selected, the present invention obviously
also applies to blades featuring a larger or a smaller number of
subdivisions and the passages 10 can be numbered and configured as
desired to provide a desired result at various heights along a
blade 6.
[0021] FIG. 4 shows further embodiments of blades according to the
present invention having different quantities and configurations of
passages 10 to create unique sets of subdivisions and airfoil
configurations at various heights of the disclosed blades 6.
Accordingly, example (a.) shows a single passage 10 creating a
profile subdivision in the center area of the blade 6. Example (b.)
shows two successive passages 10 creating profile subdivisions in
the center area of the blade 6. Example (c.) shows a blade with a
free end adjacent the casing 1 and passages 10 at the inner and
outer ends of the blade 6 creating respective profile subdivisions.
Example (d.) shows two obliquely oriented passages 10 creating
profile subdivisions arranged in the area of the trailing-edge 8
near the hub 2 and the casing 1. Example (e.) shows a single
passage 10 creating a profile subdivision near the casing 1 in the
area of the trailing-edge 8. Example (f.) shows a blade 6 with a
free end adjacent the hub 2 and having passages 10 at the inner and
outer ends of the blade 6 to create smaller profile subdivisions at
the blade ends.
[0022] FIG. 5 provides a precise definition of meridional flow
lines and flow-line profile sections. The mean meridional flow line
m is established by the geometrical center of the annulus 9 between
the casing 1 and the hub/rotor drum 2. If a perpendicular is
erected at any point of the mean flow line m, the development of
annulus width W along the flow path and a number of perpendiculars
is obtained by use of which, with equal relative division of the
perpendiculars in the direction of the annulus width, further
meridional flow lines m.sub.n may be determined. The section of a
meridional flow line m with a blade 6 provides a flow-line profile
section. Further considerations on the blade 6 according to the
present invention are based on flow-line profile sections.
[0023] FIG. 6a shows blade configurations according to the present
invention in a selected flow-line profile section. Representation
(1.) shows a subdivision into two profiles, i.e. fore-profile and
first aft-profile (N=2) which, as a result of their large maximum
thickness, are bulbous and drop-shaped. Representation (2.) shows a
subdivision into two profiles (N=2), with the fore-profile being
slender relative to the first aft-profile. Representation (3.)
shows a subdivision into two profiles (N=2), with the fore-profile
and the first aft-profile being approximately equally slender.
[0024] FIG. 6b shows further arrangements featuring a multi-profile
design according to the present invention, again in a flow-line
profile section. Representation (4.) provides a profile subdivision
into three individual profiles, i.e. fore-profile, first
aft-profile and second aft-profile (N=3), with all three profiles
having approximately equal relative thickness of more than 5
percent, and with the fore-profile and the first aft-profile being
pronouncedly bulbous. Representation (5.) provides a profile
subdivision into three individual profiles (fore-profile, first
aft-profile and second aft-profile) with the fore-profile being
slender relative to the first and second aft-profile.
Representation (6.) provides a profile subdivision into three
individual profiles (fore-profile, first aft-profile and second
aft-profile), with all three profiles having small, but
approximately equal relative thickness (less than 5 percent).
[0025] FIGS. 7a to 7c show inventive configurations of the
multi-profile design in different blade areas.
[0026] FIG. 7a shows two different blades, confined by two blade
ends not further specified, with sectional subdivision into
fore-profile and first aft-profile (N2) in the center area of the
blade, with the subdivision zone not reaching the ends of the
blade. While the blade on the left has one area in multi-profile
design, the blade on the right features multi-profile design in two
areas of the blade height.
[0027] FIG. 7b shows two different blades, each confined by at
least one fixed end, with sectional subdivision into fore-profile
and first aft-profile (N=2), with the subdivision zone reaching to
the fixed blade end. While the multi-profile design on the left
blade is oriented essentially in flow direction, the multi-profile
design on the right blade shows orientation towards the fixed wall,
characterized in that the passage 10 between the fore-profile and
the aft-profile provides for a contracting flow path, as viewed in
the blade height direction. This arrangement applies, in
particular, to the blade ends on rotor or stator platforms, as
defined by the blade roots or shrouds.
[0028] FIG. 7c shows a blade, confined by at least one free end,
with sectional subdivision into fore-profile, first aft-profile and
second aft-profile (N=3), with the subdivision zones reaching to
the free blade end and having different extension in the direction
of the blade height. While the multi-profile design in the forward
subdivision zone is oriented essentially in flow direction, the
multi-profile design in the rearward subdivision zone shows
orientation towards the free blade end, characterized in that the
passage 10 between the partial profiles provides for a contracting
flow path, as viewed in the blade height direction. This
arrangement applies, in particular, to the blade tips of rotors and
to the tips of cantilevered stators with a radial gap at the
hub.
[0029] In accordance with the present invention, it can be
particularly favorable to arrange the trailing edge of the
fore-profile in the trailing edge and rim-near zone (TRZ) of a
blade 6, see FIG. 8. The trailing edge-near zone is defined as the
portion of the blade between 40 percent and 100 percent of the
meridional blade chord length Cm. The rim-near zone is defined as
the blade portions between 0 percent and 40 percent as well as
between 60 percent and 100 percent of the annulus width (blade
height).
[0030] Further description of the present invention: [0031] 1. A
blade of a rotor or stator row for application in a fluid-flow
machine featuring a multi-profile design, with the cross-section of
the blade in at least one part of the blade height (annulus width)
in at least one flow-line profile section being formed by at least
two separate partial profiles, and each of the individual partial
profiles also featuring the shape of a blade profile. [0032] 2. A
blade in accordance with item 1, with the at least two partial
profiles, including a fore-profile and at least one aft-profile,
being of different relative maximum thickness. [0033] 3. A blade in
accordance with item 1 or 2, with at least one aft-profile having a
relative maximum thickness larger by at least 30 percent than the
upstream fore or aft-profile, respectively. [0034] 4. A blade in
accordance with item 1, with the at least two partial profiles,
including a fore-profile and at least one aft-profile, being of
equal relative maximum thickness. [0035] 5. A blade in accordance
with item 1, with the at least two partial profiles, including a
fore-profile and at least one aft-profile, being of equal absolute
maximum thickness. [0036] 6. A blade in accordance with one of the
items 1 to 5, with at least one zone having a multi-profile design
being arranged in a center area of the blade height and not
extending to the blade ends. [0037] 7. A blade in accordance with
one of the items 1 to 5, with at least one zone having a
multi-profile design being arranged on at least one fixed blade
end, confined by a blade root/shroud. [0038] 8. A blade in
accordance with one of the items 1 to 5, with at least one zone
having a multi-profile design being arranged on at least one free
blade end with a radial gap towards a hub/casing contour. [0039] 9.
A blade in accordance with one of the items 1 to 8, with the
multi-profile design, including the passages arising between the
partial profiles, being essentially oriented in the meridional flow
direction. [0040] 10. A blade in accordance with one of the items 1
to 8, with the multi-profile design, including the passages arising
between the partial profiles, featuring an inclination in a
direction of one blade end. [0041] 11. A blade in accordance with
one of the items 1 to 10, with the passage between two partial
profiles defining a contracting flow path, as viewed in a blade
height direction. [0042] 12. A blade in accordance with one of the
items 1 to 11, with a trailing edge of the fore-profile being
arranged in a trailing edge and rim-near zone (TRZ), with the
trailing edge-near zone being defined as a portion of the blade
between 40 percent and 100 percent of a meridional blade chord
length Cm, and the rim-near zone being defined as blade portion
between 0 percent and 40 percent as well as between 60 percent and
100 percent of the annulus width (blade height).
[0043] The present invention provides for a significantly higher
aerodynamic loadability of rotors and stators in fluid-flow
machines, with efficiency being maintained or even improved. A
reduction of the number of parts and the weight of the components
of more than 20 percent seems to be achievable. Application of the
concept to the high-pressure compressor of an aircraft engine with
approx. 25,000 lbs thrust leads to a reduction of the specific fuel
consumption of up to 0.5 percent.
LIST OF REFERENCE NUMERALS
[0044] 1 Casing
[0045] 2 Hub/rotor drum
[0046] 3 Machine axis
[0047] 4 Suction side
[0048] 5 Pressure side
[0049] 6 Blade
[0050] 7 Leading edge
[0051] 8 Trailing edge
[0052] 9 Annulus
[0053] 10 Passage/passage opening
* * * * *