EP1061264A1 - Warped rotor blade composed of two parts joined together - Google Patents
Warped rotor blade composed of two parts joined together Download PDFInfo
- Publication number
- EP1061264A1 EP1061264A1 EP00202050A EP00202050A EP1061264A1 EP 1061264 A1 EP1061264 A1 EP 1061264A1 EP 00202050 A EP00202050 A EP 00202050A EP 00202050 A EP00202050 A EP 00202050A EP 1061264 A1 EP1061264 A1 EP 1061264A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- piece
- rotor blade
- tail piece
- nose piece
- tail
- 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.)
- Withdrawn
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/26—Rotors specially for elastic fluids
- F04D29/32—Rotors specially for elastic fluids for axial flow pumps
- F04D29/38—Blades
- F04D29/388—Blades characterised by construction
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/26—Rotors specially for elastic fluids
- F04D29/32—Rotors specially for elastic fluids for axial flow pumps
- F04D29/34—Blade mountings
- F04D29/36—Blade mountings adjustable
- F04D29/362—Blade mountings adjustable during rotation
Definitions
- the present invention relates to the technological field of propellers, fans or more generally to twin-blade or multi-blade rotors which are used for aeronautical applications or for ventilation purposes since they produce with their movement an axial air flow parallel to their axis of rotation.
- the invention relates to a blade suitable for being fixed to the hub of a rotor.
- sections of a blade located at different radial distances from the axis of the hub, i.e. the axis of rotation, have different tangential translation speeds for the same angular speed of rotation of the rotor.
- the net thrust area of a blade normally increases in the direction from the end of said blade towards the hub.
- blades made of glass-fibre reinforced plastic are used, it being possible to produce said blades with parabolic or hyperbolic warping during manufacture thereof.
- blades are made composed of a nose piece and a tail piece, said parts extending linearly along the whole longitudinal extension of the said blades and being joined together after undergoing varied twisting.
- These two parts are formed from box-type extruded sections, i.e. having the outline of their profile closed perimetrically, with the tail profile having a cross section covering a small area compared to that of the nose profile.
- a rotor blade which is obtained by means of two parts, i.e. a nose piece and a tail piece, joined together and in which the cross-sectional shape of the tail piece is such that it satisfies the requirements with regard to lift and static thrust, but has a limited torsional and flexural strength, thus being suitable for deformation with warping angles which are variable in accordance with a desired non-linear pattern in the direction of the longitudinal axis of the said blade, without its external edges assuming contours which cannot be matched with those of the end part of the nose piece onto which it is to be fixed.
- the present invention in fact relates to a rotor blade as described in the preamble of the accompanying Claim 1, characterized by the characterizing part of the same claim.
- a blade 1 according to the invention is composed of a nose piece 2 and a tail piece 3 which can be assembled together: the tail piece 3 is formed from a hollow extruded section in the form of an open "V" with a desired thickness of its walls.
- the free ends 3m, 3n of the tail piece are shaped so that they have a profile matching two recesses 2p, 2q formed on the end part 2t of the nose piece 2 which is formed from an extruded section of the box type, i.e. with a closed contour.
- the two parts 2, 3 forming the blade 1 may be joined together: the low torsional and flexural strength of the two sides of the open "V" forming the tail piece 3 facilitates the said warping and in particular, also during the assembly stage, allows warping thereof, if necessary, to be modified slightly in a suitable manner, section by section, so as to achieve perfect mating of the aligned edges of the two parts 2, 3 assembled together as shown in Figure 4.
- the invention thus provides a blade 1 with non-linear warping (see progression of warping angle ⁇ in Figures 1 to 3) which can be achieved by means of simple operations and using extruded sections, preferably made of aluminium, having a low cost, thus achieving the predefined objects of the inventor.
- the two parts 2, 3, after assembly, may be fixed using known techniques such as, for example, riveting, welding or gluing using special structural adhesives known to persons skilled in the art.
Abstract
Description
- The present invention relates to the technological field of propellers, fans or more generally to twin-blade or multi-blade rotors which are used for aeronautical applications or for ventilation purposes since they produce with their movement an axial air flow parallel to their axis of rotation.
- More particularly, the invention relates to a blade suitable for being fixed to the hub of a rotor.
- As persons skilled in the art know, sections of a blade located at different radial distances from the axis of the hub, i.e. the axis of rotation, have different tangential translation speeds for the same angular speed of rotation of the rotor.
- Moreover, for geometrical and structural reasons, the net thrust area of a blade normally increases in the direction from the end of said blade towards the hub.
- In order to obtain a flow weight per unit of area of the disc traced by the blades of a rotor having a uniform value over the entire area of the said disc, so as to prevent turbulence or associated energy losses, it is required to "warp" the blades, imparting to them a twist about their longitudinal axis with different angles of torsion, from one section to another, which therefore vary in a predefined manner and which, starting from zero at the end of the blade, increase in the direction towards the hub.
- For certain applications such as, for example, large-diameter multi-blade rotors for fans, intended for heat exchangers or cooling towers, it has been noted how, in order to obtain the uniform flow described above, it is required to produce warping of the blades with amplitudes of the warping angle which vary in accordance with curves of the second order (parabolas, hyperbolas).
- In order to obtain such warping for fans with a diameter of up to 12 m, applying torsional mechanical stresses to the blades produces difficulties and complications such that, in these cases, it is preferred to produce warping with a linear variation in the associated angle, thus accepting a priori a substantial reduction in the efficiency.
- In the cases where a substantially higher cost is acceptable, blades made of glass-fibre reinforced plastic are used, it being possible to produce said blades with parabolic or hyperbolic warping during manufacture thereof.
- In order to attempt to solve the problem of creating warped rotor blades which are low-cost, i.e. made of aluminium, according to the present state of the art blades are made composed of a nose piece and a tail piece, said parts extending linearly along the whole longitudinal extension of the said blades and being joined together after undergoing varied twisting. These two parts are formed from box-type extruded sections, i.e. having the outline of their profile closed perimetrically, with the tail profile having a cross section covering a small area compared to that of the nose profile.
- The abovementioned "box-type" geometrical form ensures that the torsional strength modulus of the tail piece, despite the small area of its cross section, in any case has a significant value and in particular is almost constant along the whole longitudinal extension of the said part: these two factors in combination firstly make it extremely difficult to perform non-linear warping of the tail piece and secondly result in the contours of the tail piece after warping - especially in its sections where the warping angle is more accentuated - being such that they cannot be precisely matched with those of the end of the nose profile onto which they are to be fixed.
- This results in the need to perform major adjustments in order to join the two parts together, moreover with results which are not satisfactory from the point of view of the quality of workmanship and the performance achieved.
- In order to overcome the abovementioned drawbacks, the inventor of the present invention has devised a rotor blade which is obtained by means of two parts, i.e. a nose piece and a tail piece, joined together and in which the cross-sectional shape of the tail piece is such that it satisfies the requirements with regard to lift and static thrust, but has a limited torsional and flexural strength, thus being suitable for deformation with warping angles which are variable in accordance with a desired non-linear pattern in the direction of the longitudinal axis of the said blade, without its external edges assuming contours which cannot be matched with those of the end part of the nose piece onto which it is to be fixed.
- This result is obtained by forming the said tail piece from a section having a cross section terminating in the form of an open "V", it being understood by this that the said cross section may have globally this form, as in the example which will be described below.
- The present invention in fact relates to a rotor blade as described in the preamble of the accompanying
Claim 1, characterized by the characterizing part of the same claim. - An example of embodiment which is to be regarded as non-limiting and not binding with regard to other embodiments which can be obtained by changing the form of its parts and the profile of their sections, will now be described in greater detail.
- During the description reference will also be made to the accompanying drawings in which:
- Figure 1 shows an exploded view of the cross section of a preferred embodiment of a blade according to the invention (composed of two parts) along the region of its free end;
- Figure 2 shows an exploded view of the cross section of the blade according to Figure 1 along its middle section;
- Figure 3 shows an exploded view of the cross section of the blade according to Figures 1 and 2 in the region of its base, i.e. in the vicinity of its point of attachment to the hub;
- Figure 4 shows a cross-sectional view of the blade along its middle section with the two parts which form it being assembled.
- With reference to Figures 1, 2 and 3, it can be seen how a
blade 1 according to the invention is composed of anose piece 2 and atail piece 3 which can be assembled together: thetail piece 3 is formed from a hollow extruded section in the form of an open "V" with a desired thickness of its walls. - The
free ends recesses end part 2t of thenose piece 2 which is formed from an extruded section of the box type, i.e. with a closed contour. - After the two
parts blade 1 have undergone warping in the desired manner, they may be joined together: the low torsional and flexural strength of the two sides of the open "V" forming thetail piece 3 facilitates the said warping and in particular, also during the assembly stage, allows warping thereof, if necessary, to be modified slightly in a suitable manner, section by section, so as to achieve perfect mating of the aligned edges of the twoparts - The invention thus provides a
blade 1 with non-linear warping (see progression of warping angle α in Figures 1 to 3) which can be achieved by means of simple operations and using extruded sections, preferably made of aluminium, having a low cost, thus achieving the predefined objects of the inventor. - The two
parts - It is obvious that the shape of the two parts, i.e. nose piece and tail piece, constituting a rotor blade according to the invention may be modified with respect to the example illustrated hitherto depending on design requirements and the type of aerodynamic profile which is to be obtained.
- Constructional forms thus obtained nevertheless fall within the protective scope of the present application provided that they are based on the concepts expressed in the accompanying
Claim 1.
Claims (6)
- Rotor blade (1) having a warping angle (α) variable in a predefined manner from its base to its end, the said blade being formed by means of joining together a nose piece (2) and a tail piece (3) designed to form, when joined together, a given aerodynamic profile with cross sections having predefined shapes, characterized in that the said tail piece (3) is hollow and has substantially a shape terminating in an open "V", the free ends (3m, 3n) of the sides of which are designed to be joined to the end part (2t) of the said nose piece (2).
- Rotor blade according to Claim 1, in which the said free ends (3m, 3n) of the tail piece (3) terminating in an open "V" have a profile matching recesses (2p, 2q) formed along the whole length of the blade (1) on the said end part (2t) of the said nose piece (2).
- Rotor blade according to one of the preceding claims, in which the said nose piece (2) and the said tail piece (3) are fixed together by means of structural adhesives.
- Rotor blade according to one of Claims 1 or 2, in which the said nose piece (2) and the said tail piece (3) are fixed together by means of riveting.
- Rotor blade according to one of Claims 1 or 2, in which the said nose piece (2) and the said tail piece (3) are fixed together by means of welding.
- Rotor blade according to one of the preceding claims, characterized in that both the said nose piece (2) and the said tail piece (3) which form it are extruded sections made of aluminium.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT1999MI001321A ITMI991321A1 (en) | 1999-06-14 | 1999-06-14 | TWISTED IMPELLER FOR IMPELLER COMPOSED OF TWO JOINT ELEMENTS |
ITMI991321 | 1999-06-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1061264A1 true EP1061264A1 (en) | 2000-12-20 |
Family
ID=11383163
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00202051A Withdrawn EP1061263A1 (en) | 1999-06-14 | 2000-06-08 | Rotor with blades attached to a hub by bearings contained in a bush |
EP00202050A Withdrawn EP1061264A1 (en) | 1999-06-14 | 2000-06-08 | Warped rotor blade composed of two parts joined together |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00202051A Withdrawn EP1061263A1 (en) | 1999-06-14 | 2000-06-08 | Rotor with blades attached to a hub by bearings contained in a bush |
Country Status (2)
Country | Link |
---|---|
EP (2) | EP1061263A1 (en) |
IT (1) | ITMI991321A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL1019437C2 (en) * | 2001-11-26 | 2003-05-27 | Ventilatoren Sirocco Howden Bv | Fan rotor blade with flap, has flap section with cross section defining two different angle geometry regions |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3025748B1 (en) * | 2014-09-11 | 2016-11-18 | Gea Batignolles Tech Thermiques | FAN FOR FRESH AIR. |
US10137980B2 (en) * | 2015-07-13 | 2018-11-27 | Ge Aviation Systems Llc | Hub assembly and propeller assemblies |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB856668A (en) * | 1958-07-10 | 1960-12-21 | Air Control Installations Ltd | Improvements in or relating to axial-flow rotary impellers |
US4892460A (en) * | 1989-01-30 | 1990-01-09 | Volk Steve J | Propeller breeze enhancing blades for conventional ceiling fans |
US5328330A (en) * | 1993-08-02 | 1994-07-12 | Hudson Products Corporation | Extruded aluminum fan blade |
US5328329A (en) * | 1993-07-06 | 1994-07-12 | Hudson Products Corporation | Fan blade width extender |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB254377A (en) * | 1925-03-30 | 1926-06-30 | Bramson Mogens Louis | Improvements in or relating to variable pitch propellers |
GB1023824A (en) * | 1961-12-07 | 1966-03-23 | Aerex Ltd | Improvements in and relating to variable or adjustable pitch fans |
-
1999
- 1999-06-14 IT IT1999MI001321A patent/ITMI991321A1/en unknown
-
2000
- 2000-06-08 EP EP00202051A patent/EP1061263A1/en not_active Withdrawn
- 2000-06-08 EP EP00202050A patent/EP1061264A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB856668A (en) * | 1958-07-10 | 1960-12-21 | Air Control Installations Ltd | Improvements in or relating to axial-flow rotary impellers |
US4892460A (en) * | 1989-01-30 | 1990-01-09 | Volk Steve J | Propeller breeze enhancing blades for conventional ceiling fans |
US5328329A (en) * | 1993-07-06 | 1994-07-12 | Hudson Products Corporation | Fan blade width extender |
US5328330A (en) * | 1993-08-02 | 1994-07-12 | Hudson Products Corporation | Extruded aluminum fan blade |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL1019437C2 (en) * | 2001-11-26 | 2003-05-27 | Ventilatoren Sirocco Howden Bv | Fan rotor blade with flap, has flap section with cross section defining two different angle geometry regions |
Also Published As
Publication number | Publication date |
---|---|
ITMI991321A1 (en) | 2000-12-14 |
ITMI991321A0 (en) | 1999-06-14 |
EP1061263A1 (en) | 2000-12-20 |
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