CA2047276A1 - Control of frequency and weight distribution in high efficient blading - Google Patents
Control of frequency and weight distribution in high efficient bladingInfo
- Publication number
- CA2047276A1 CA2047276A1 CA 2047276 CA2047276A CA2047276A1 CA 2047276 A1 CA2047276 A1 CA 2047276A1 CA 2047276 CA2047276 CA 2047276 CA 2047276 A CA2047276 A CA 2047276A CA 2047276 A1 CA2047276 A1 CA 2047276A1
- Authority
- CA
- Canada
- Prior art keywords
- blade
- blades
- tip
- base
- hollow
- 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.)
- Abandoned
Links
Landscapes
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
55,703 ABSTRACT OF THE DISCLOSURE
A method for forming a long, low pressure rotating blade for a steam turbine and a blade formed thereby.
The blade is formed in an airfoil configuration providing optimum blade width distribution from base to tip corresponding to a selected optimum steam passage efficiency. A hollow is formed within the blade beginning at the blade tip and extends toward the blade base. The hollow is centered with respect to the blade axis and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while sufficient material from the blade is removed to maintain centrifugal stress loading within design limits.
A method for forming a long, low pressure rotating blade for a steam turbine and a blade formed thereby.
The blade is formed in an airfoil configuration providing optimum blade width distribution from base to tip corresponding to a selected optimum steam passage efficiency. A hollow is formed within the blade beginning at the blade tip and extends toward the blade base. The hollow is centered with respect to the blade axis and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while sufficient material from the blade is removed to maintain centrifugal stress loading within design limits.
Description
7 ~
- 1 - 55,703 CON~ROL OF FRBQUENCY AND WEIGHT DISTRIB~TION
IN HIGH EFFICIENT BLaDING
BACKGROUND OF THE INVENTION
The present invention relates to steam turbine blading and, more particularly, to a method and apparatus for controlling resonant frequency and weight distribution in rotating turbine blades.
Highly loaded rotating steam turbine blades as well as long, low pressure steam turbine blades having low hub-to-tip ratios are generally twisted and tapered. Twisting is necessary to accommodate the pressure gradient occurring in front o~ the rotating blade along with the change in wheel speed occurring in the same region. As a resuit, blade inlet angles change dramatically between blade base and tip.
Blade tapering is employed to controI centrifugal stres~. Control of such stress requires an appreciably lower cross-sectional area at the blade tip than at the bladP base. In order to maintain a finite thickness at the blade tip, the blade width must be reduced.
- 1 - 55,703 CON~ROL OF FRBQUENCY AND WEIGHT DISTRIB~TION
IN HIGH EFFICIENT BLaDING
BACKGROUND OF THE INVENTION
The present invention relates to steam turbine blading and, more particularly, to a method and apparatus for controlling resonant frequency and weight distribution in rotating turbine blades.
Highly loaded rotating steam turbine blades as well as long, low pressure steam turbine blades having low hub-to-tip ratios are generally twisted and tapered. Twisting is necessary to accommodate the pressure gradient occurring in front o~ the rotating blade along with the change in wheel speed occurring in the same region. As a resuit, blade inlet angles change dramatically between blade base and tip.
Blade tapering is employed to controI centrifugal stres~. Control of such stress requires an appreciably lower cross-sectional area at the blade tip than at the bladP base. In order to maintain a finite thickness at the blade tip, the blade width must be reduced.
2 ~ ~
- 2 - 55,703 Twisting and tapering of steam turbine blading reduces the flow control region near the blade tips.
There is also a resultant larger inlet flow angle and a smaller magnitude of flow turning at the blade tip.
As a consequence, blading efficiency is reduced.
Moreo~er, in highly loaded blading, particularly last row low pressure blading, steam velocity can be highly supersonic. For such blading, it is desirable to use convergent-divergent flow passages to improve efficiency. However, such flow passage configuration is difficult to achieve where pitch-to width ratios are large such as at the tips of long, low pressure blading.
SUMMARY OF THE INVENTION
; :
It is an object of the present invention to provide a method and apparatus which overcomes the disadvantages of prior art steam turbine blading as set forth above.
It is a further object of the present invention to provide a method and apparatus for forming a steam turbine blade which allows the tip end of the blade to have the same degree of flow control passage area as a base end of a blade and allow for the development of convergent-divergent flow passages.
In accordance with one form of the present invention, there is provided a method for forming a long, low pressure rotating blade for a steam turbine in which the blade has a base end and a tip end with the base end being attached to the rotor of the turbine in a blade row which includes a plurality of such blades. Each adjacent pair of blades defines a steam flow passage from base to tip of the blades.
7 2 ~ 6 - 3 - 55,703 The method includes forming a blade having an airfoil configuration which provides an optimum blade width distribution from base end to tip end corresponding to a selected optimum steam flow control passage. A
hollow is machined within the blade beginning at the blade tip and extending toward the blade base. The hollow is centered with respect to the blade axis and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing su-fficient material from the blade to maintain centrifugal stress loading within design limits. The hollow is configured and sufficient material removed so as to tune each individual blade in a manner that avoids the blade having any natural resonant frequencies which coincide with excitation frequencies to be experienced within the steam turbine. In one form, the material is removed from the blade using electro-discharge machining or electro-chemical machin;ng.
~ILE DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is an elevation view of a turbine blad~ of the prior art;
FIGS. 2 and 3 are cross-sectional views taken through the blade of FIG. 1 at th~ lashing wires 12 and 14;
FIG. 4 is a radial cross-sectional view of an adjacent pair of stea~ turbine blades such as that illustrated in FIG. 1 showing the flow control area;
7 2 ~ ~
- 2 - 55,703 Twisting and tapering of steam turbine blading reduces the flow control region near the blade tips.
There is also a resultant larger inlet flow angle and a smaller magnitude of flow turning at the blade tip.
As a consequence, blading efficiency is reduced.
Moreo~er, in highly loaded blading, particularly last row low pressure blading, steam velocity can be highly supersonic. For such blading, it is desirable to use convergent-divergent flow passages to improve efficiency. However, such flow passage configuration is difficult to achieve where pitch-to width ratios are large such as at the tips of long, low pressure blading.
SUMMARY OF THE INVENTION
; :
It is an object of the present invention to provide a method and apparatus which overcomes the disadvantages of prior art steam turbine blading as set forth above.
It is a further object of the present invention to provide a method and apparatus for forming a steam turbine blade which allows the tip end of the blade to have the same degree of flow control passage area as a base end of a blade and allow for the development of convergent-divergent flow passages.
In accordance with one form of the present invention, there is provided a method for forming a long, low pressure rotating blade for a steam turbine in which the blade has a base end and a tip end with the base end being attached to the rotor of the turbine in a blade row which includes a plurality of such blades. Each adjacent pair of blades defines a steam flow passage from base to tip of the blades.
7 2 ~ 6 - 3 - 55,703 The method includes forming a blade having an airfoil configuration which provides an optimum blade width distribution from base end to tip end corresponding to a selected optimum steam flow control passage. A
hollow is machined within the blade beginning at the blade tip and extending toward the blade base. The hollow is centered with respect to the blade axis and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing su-fficient material from the blade to maintain centrifugal stress loading within design limits. The hollow is configured and sufficient material removed so as to tune each individual blade in a manner that avoids the blade having any natural resonant frequencies which coincide with excitation frequencies to be experienced within the steam turbine. In one form, the material is removed from the blade using electro-discharge machining or electro-chemical machin;ng.
~ILE DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is an elevation view of a turbine blad~ of the prior art;
FIGS. 2 and 3 are cross-sectional views taken through the blade of FIG. 1 at th~ lashing wires 12 and 14;
FIG. 4 is a radial cross-sectional view of an adjacent pair of stea~ turbine blades such as that illustrated in FIG. 1 showing the flow control area;
7 2 ~ ~
- 4 - 55,703 FIG. 5 is a cross-sectional view near the tip end of the pair of steam turbine blades o~ FIG. 4 showing the reduced steam flow control area;
FIG. 6 is an elevation view of a steam turbine blade utilizing the teaching of the present invention;
FIG. 7 is a partial cross-sectional view of the blade of FIG. 6 showing the method of forming a hollow tip portion; and FIG. 8 is a view similar to that of FIG. 5 but lf~ utilizing the blades of FIG. 6.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an elevation view of a steam turbine blade exemplary of the prior art taken transvexse to the normal plane of rotation of the blade. In this plane, the blade 10 is essentially a tapered blade having a pair of connecting points 12 and 14 for atkaching the blade to adjacent blades. Preferably, the blades are grouped and tuned in such groups to avoid resonance in the tangential, axial, and torsional modes with multiple harmonics. The tuning also is designed to avoid excitation of frequencies at multiples of the turbine speed. The connecting point 12, 14 are referred to as inner and outer lashing wires. The blade may be formed with a zero taper angle at the base to simplify the manufacturing process but with the foil portion tapered and twisted and varying from, ~or example, 4.25 inches at the base end 16 to an axial width at the blade tip end 18 of about 1.22 inches. The blades are attached at the base end 16 to a rotor (not shown) of a steam turbine and are coupled together by means of the lashing wires 12 and 14 in selecked groups. A blade row comprises a plurality of the blades 10 attach~ed to a rotor in a 2 ~ ~
FIG. 6 is an elevation view of a steam turbine blade utilizing the teaching of the present invention;
FIG. 7 is a partial cross-sectional view of the blade of FIG. 6 showing the method of forming a hollow tip portion; and FIG. 8 is a view similar to that of FIG. 5 but lf~ utilizing the blades of FIG. 6.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an elevation view of a steam turbine blade exemplary of the prior art taken transvexse to the normal plane of rotation of the blade. In this plane, the blade 10 is essentially a tapered blade having a pair of connecting points 12 and 14 for atkaching the blade to adjacent blades. Preferably, the blades are grouped and tuned in such groups to avoid resonance in the tangential, axial, and torsional modes with multiple harmonics. The tuning also is designed to avoid excitation of frequencies at multiples of the turbine speed. The connecting point 12, 14 are referred to as inner and outer lashing wires. The blade may be formed with a zero taper angle at the base to simplify the manufacturing process but with the foil portion tapered and twisted and varying from, ~or example, 4.25 inches at the base end 16 to an axial width at the blade tip end 18 of about 1.22 inches. The blades are attached at the base end 16 to a rotor (not shown) of a steam turbine and are coupled together by means of the lashing wires 12 and 14 in selecked groups. A blade row comprises a plurality of the blades 10 attach~ed to a rotor in a 2 ~ ~
- 5 - 55,703 common circumferential row. A typical blade row may contain 120 of the blades of FIG. 1. FIGS. 2 and 3 illustrate cross-sections of the blades taken through the lashing wires 12 and 14 and illustrate the reduction in blade width at the two different radial distances ~rom the rotor and also the variation in blade curvature. FIGS. 4 and 5 are radial views of a pair of adjacent blades showing the difference in steam flow control area at a location adjacent the base of a blade as compared to an area adjacent the tip end of a pair of blades. In FIG. 4, the flow control area 15 extends throughout the concave surface of one blade and the convex surface of the ad;acent blade whereas in FIG. 5, the flow control area 17 extends only over a small percentage of the blade surfaces. In a blade of the type illustrated in FIG.
1, the ratio of pitch to-width at the blade tip is approximately ten times the ratio of pitch-to-width at the blade base, where blade width and pitch are measurements of the dimensions indicated in FIGS. 4 and 5.
FIG. 6 is an elevation view of a steam turbine blade similar to that shown in FIG. l but in which the teaching of the present invention has been employed to allow the tip end 20 of the blade to have a greater width. The blade 22 includes a base end 24 which may have substantially the same width as the tip end 20.
The base en~ 24 may be mounted to a dovetail root section 26 in the same manner as was done with respect to the prior art in FIG. I. FIG. 7 is a partial cross-sectional view of the tip end of the blade of FIG. 6 showing the forming of a cutout portion 28 or hollow within the tip end of the blade 22. The hollow portion is indicated by the dashed lines 30 and extends downward towards the base end of the blade a - 6 - 55,703 predetermined radial distance which varies as a function of the design constraints placed on the blade. ~he design constraints may be established by centrifugal stresses on the blade and by the need to machine or remove sufficient material from the blad~
to avoid natural resonant frequencies. FIG. 8 is a radial view of the tip end 20 of a pair of blades 22 showing the extended steam flow control passage 19 at the tip end of the blades. It should be noted that the use of the method of hollowing out the tip ends of the blades 22 allows the outside dimensions of the blade to be formed in any desired configuration. For example, in the view of FIG. 8, the blade configuration will be seen to form a convergent-divergent flow control passage. Such configuration of passages has been very difficult with tapered blades characteristic of the prior art.
In order to obtain the required cross-sectional foil area of the blade, electro-discharge milling (EDM) or electro-chemical milling (ECM) may be used to form the hollows within the tip ends of the blades.
It will be appreciated that the hollow portion can be extended to any desired depth at any taper angle required. The precise characteristics of EC~ and EDM
machining allow the manufacturer to maintain any required thickness of the wall of the blade. The particular details of ECM and ED~ machine are well known in the art and are not considered part of the present invention. By allowing the blads to be machined with a hollow tip end, the blade itself can be designed with any blade width distribution re~uired to give optimum steam flow passage efficiency.
By use of the method of the present invention for forming a hollow passage within the tip ends of long, low pressure steam blading, blading can be machined to ~7~7~
1, the ratio of pitch to-width at the blade tip is approximately ten times the ratio of pitch-to-width at the blade base, where blade width and pitch are measurements of the dimensions indicated in FIGS. 4 and 5.
FIG. 6 is an elevation view of a steam turbine blade similar to that shown in FIG. l but in which the teaching of the present invention has been employed to allow the tip end 20 of the blade to have a greater width. The blade 22 includes a base end 24 which may have substantially the same width as the tip end 20.
The base en~ 24 may be mounted to a dovetail root section 26 in the same manner as was done with respect to the prior art in FIG. I. FIG. 7 is a partial cross-sectional view of the tip end of the blade of FIG. 6 showing the forming of a cutout portion 28 or hollow within the tip end of the blade 22. The hollow portion is indicated by the dashed lines 30 and extends downward towards the base end of the blade a - 6 - 55,703 predetermined radial distance which varies as a function of the design constraints placed on the blade. ~he design constraints may be established by centrifugal stresses on the blade and by the need to machine or remove sufficient material from the blad~
to avoid natural resonant frequencies. FIG. 8 is a radial view of the tip end 20 of a pair of blades 22 showing the extended steam flow control passage 19 at the tip end of the blades. It should be noted that the use of the method of hollowing out the tip ends of the blades 22 allows the outside dimensions of the blade to be formed in any desired configuration. For example, in the view of FIG. 8, the blade configuration will be seen to form a convergent-divergent flow control passage. Such configuration of passages has been very difficult with tapered blades characteristic of the prior art.
In order to obtain the required cross-sectional foil area of the blade, electro-discharge milling (EDM) or electro-chemical milling (ECM) may be used to form the hollows within the tip ends of the blades.
It will be appreciated that the hollow portion can be extended to any desired depth at any taper angle required. The precise characteristics of EC~ and EDM
machining allow the manufacturer to maintain any required thickness of the wall of the blade. The particular details of ECM and ED~ machine are well known in the art and are not considered part of the present invention. By allowing the blads to be machined with a hollow tip end, the blade itself can be designed with any blade width distribution re~uired to give optimum steam flow passage efficiency.
By use of the method of the present invention for forming a hollow passage within the tip ends of long, low pressure steam blading, blading can be machined to ~7~7~
- 7 ~ 55,703 have practically unlimited resonant frequency control and foil section area conkrol. Furthermore, the flow passage control can be designed to provide higher efficiency steam flow passages near the tip end of steam blading. Additionally, the tip end of the steam blading can be designed to accommodate convergent or convergent-divergent flow passages which are not available in the prior art. Furthermore, the external configuration of the blading is provided with greater flexibility since the centrifugal stresses and frequency tuning can be achieved by hollowing the blade to any desired cross-sectional area or depth.
Still further, the lashing required in the prior art to join adjacent blades in order to prevent undesirable vibrations may be eliminated since each of the blades may be individually tuned to avoid resonant frequency vibration. This elimination of lashing wires may also improve steam flow efficiency. And further, a costs savings may be achieved by using fewer blades per row of blades since the width of the blades at the blade tips may be increased. More particularly, it is expected that performance gains utilizing steam flow control in the-blade tip region will provide a 0.4% heat rate improvement and elimination of lashing wires may provide as much as 0.3% heat rate improvement. In a typical fossil fueled turbine generator unit, this heat rate improvement may be in the order of 52 BTU's/KW hour.
It will be appreciated that what has been described is a method for forming a long, low pressure rotating blade for a steam turbine in which the blade has a base end and a tip end which may be of substantially the same width and provides substantially the same pitch/width between adjacent blades. The base end is att~ched to a rotor o~ a - 8 - 55,703 turbine in a blade row which includes a plurality of such blades so that each adjacent pair of blades defines a steam flow passage which may be convergent-divergent and provide greater steam flow control. In the disclosed method, the blade i~ formed with a foil configuration providing an optimum blade width distribution from base to tip, which configuration corresponds to a selected optimum steam passage efficiency. A hollow is machined within the blade beginning at the blade tip end and extending toward the blade base end. The hollow is centered with respect to an axis of the blade and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing sufficient material from the blade to maintain centrifugal str~ss loading within design limits for the blade. In one form, the material may be removed from the blade by EDM or ECM machining. The disclosed method allows the outer configuration of the blade to be any selected configuration.
While the invention has been described in what is presently considered to be a preferred embodiment, other variations and modifications will become apparent to those skilled in the art. It i5 intended, therefore, that the invention not be limited to the disclosed embodiment but be interpreted within the full spirit and scope of the appended claims.
Still further, the lashing required in the prior art to join adjacent blades in order to prevent undesirable vibrations may be eliminated since each of the blades may be individually tuned to avoid resonant frequency vibration. This elimination of lashing wires may also improve steam flow efficiency. And further, a costs savings may be achieved by using fewer blades per row of blades since the width of the blades at the blade tips may be increased. More particularly, it is expected that performance gains utilizing steam flow control in the-blade tip region will provide a 0.4% heat rate improvement and elimination of lashing wires may provide as much as 0.3% heat rate improvement. In a typical fossil fueled turbine generator unit, this heat rate improvement may be in the order of 52 BTU's/KW hour.
It will be appreciated that what has been described is a method for forming a long, low pressure rotating blade for a steam turbine in which the blade has a base end and a tip end which may be of substantially the same width and provides substantially the same pitch/width between adjacent blades. The base end is att~ched to a rotor o~ a - 8 - 55,703 turbine in a blade row which includes a plurality of such blades so that each adjacent pair of blades defines a steam flow passage which may be convergent-divergent and provide greater steam flow control. In the disclosed method, the blade i~ formed with a foil configuration providing an optimum blade width distribution from base to tip, which configuration corresponds to a selected optimum steam passage efficiency. A hollow is machined within the blade beginning at the blade tip end and extending toward the blade base end. The hollow is centered with respect to an axis of the blade and has a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing sufficient material from the blade to maintain centrifugal str~ss loading within design limits for the blade. In one form, the material may be removed from the blade by EDM or ECM machining. The disclosed method allows the outer configuration of the blade to be any selected configuration.
While the invention has been described in what is presently considered to be a preferred embodiment, other variations and modifications will become apparent to those skilled in the art. It i5 intended, therefore, that the invention not be limited to the disclosed embodiment but be interpreted within the full spirit and scope of the appended claims.
Claims (5)
1. A method for forming a long, low pressure rotating blade for a steam turbine, the blade having a base end and a tip end with the base being attached to a rotor of the turbine in a blade row including a plurality of such blades, each adjacent pair of blades defining a steam flow passage therebetween, the method comprising the steps of:
forming a blade having a foil configuration providing an optimum blade width distribution from base to tip corresponding to a selected optimum steam passage efficiency; and machining a hollow within the blade beginning at the blade tip and extending toward the blade base, the hollow being centered with respect to the blade axis and having a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing sufficient material from the blade to maintain centrifugal stress loading within design limits.
- 10 - 55,703
forming a blade having a foil configuration providing an optimum blade width distribution from base to tip corresponding to a selected optimum steam passage efficiency; and machining a hollow within the blade beginning at the blade tip and extending toward the blade base, the hollow being centered with respect to the blade axis and having a cross-sectional area so as to maintain blade wall thickness within structural design limits while removing sufficient material from the blade to maintain centrifugal stress loading within design limits.
- 10 - 55,703
2. The method of claim 1 wherein the step of machining comprises the step of electro-discharge milling.
3. The method of claim 1 wherein the step of machining comprises the step of electro-chemical milling.
4. The method of claim 2 wherein the machining step forms a tapered hollow within the blade having a shape corresponding to an exterior blade configuration and extending a predetermined depth into the blade from the blade tip.
5. A rotating blade row for a steam turbine comprising a plurality of long, low pressure blades each having a base end attached to a rotor of the steam turbine and a tip end extending radially outward from the rotor, each of the blades having a selected optimum blade width distribution from base end to tip end so as to define a selected optimum steam passage efficiency between adjacent ones of the blades, and each of the blades being hollow from blade tip end to a predetermined radial dimension from the base end such that each blade is frequency tuned to avoid excitation of natural resonant frequencies during operation of the turbine and to limit centrifugal stresses on the blades to within blade structural limits.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55351690A | 1990-07-18 | 1990-07-18 | |
| US553,516 | 1990-07-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2047276A1 true CA2047276A1 (en) | 1992-01-19 |
Family
ID=24209697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2047276 Abandoned CA2047276A1 (en) | 1990-07-18 | 1991-07-17 | Control of frequency and weight distribution in high efficient blading |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH04232305A (en) |
| CA (1) | CA2047276A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1439281A2 (en) | 2003-01-18 | 2004-07-21 | Rolls-Royce Deutschland Ltd & Co KG | Gas turbine engine blade |
| CN102962653A (en) * | 2012-11-09 | 2013-03-13 | 哈尔滨汽轮机厂有限责任公司 | Triaxial numerical control machining method for penultimate-stage moving blade of steam turbine |
| CN106446324A (en) * | 2016-07-19 | 2017-02-22 | 杭州汽轮机股份有限公司 | Design method for last-stage torsional blade of large industrial steam turbine |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5245429A (en) * | 1975-10-06 | 1977-04-09 | Kansai Seiki Seisakusho:Kk | Shooting game machine |
-
1991
- 1991-07-11 JP JP17100891A patent/JPH04232305A/en active Pending
- 1991-07-17 CA CA 2047276 patent/CA2047276A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1439281A2 (en) | 2003-01-18 | 2004-07-21 | Rolls-Royce Deutschland Ltd & Co KG | Gas turbine engine blade |
| EP1439281A3 (en) * | 2003-01-18 | 2006-10-18 | Rolls-Royce Deutschland Ltd & Co KG | Gas turbine engine blade |
| CN102962653A (en) * | 2012-11-09 | 2013-03-13 | 哈尔滨汽轮机厂有限责任公司 | Triaxial numerical control machining method for penultimate-stage moving blade of steam turbine |
| CN106446324A (en) * | 2016-07-19 | 2017-02-22 | 杭州汽轮机股份有限公司 | Design method for last-stage torsional blade of large industrial steam turbine |
| CN106446324B (en) * | 2016-07-19 | 2019-12-06 | 杭州汽轮机股份有限公司 | Design method of final-stage twisted blade of large industrial steam turbine |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04232305A (en) | 1992-08-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |