WO2005026501A1

WO2005026501A1 - Turbine rotor blade

Info

Publication number: WO2005026501A1
Application number: PCT/JP2003/011564
Authority: WO
Inventors: Tomomi Nakajima; Eiji Saito; Yutaka Yamashita; Hideo Yoda; Kenichiro Nomura
Original assignee: Hitachi, Ltd.
Priority date: 2003-09-10
Filing date: 2003-09-10
Publication date: 2005-03-24
Also published as: JPWO2005026501A1; JP4299301B2; AU2003266505A1

Abstract

A turbine rotor blade (1) with a cover (3) restricting a twist at a blade tip part (2), wherein a profile part (4) is formed so that at least the centroid of the blade tip part (2) in a blade cross section can be displaced from the radial line (R) of a turbine extending from the centroid of a blade root part (5) in the blade cross section, the tilted direction of a contact surface (Z) between the covers (3, 3) relative to the axis (A) of the turbine is set so that a pressing force can act between the covers (3, 3) adjacent to each other in circumferential direction according to the positional relation of the centroid to the radial line and the rotation direction of the profile part (4), whereby even when the length of the blade is rather short, an assembly operation can be facilitated and a local stress concentration can be suppressed by sufficiently assuring a connection force between the covers at the time of rotation to increase a reliability.

Description

Description Turbine rotor blade Technical field

The present invention relates to a turbine rotor blade provided with a cover for restraining twist at a blade tip. Background art

The shape of the evening bin blade is closely related to the efficiency of the evening bin used in the power plant, and is being improved every day to achieve higher efficiency. For the purpose of achieving high efficiency in this way, for example, as described in Japanese Patent Application Laid-Open No. 2001-210205, the working fluid passes between cascades. In order to reduce the secondary flow loss that occurs near the wall surface, the turbine is inclined with respect to the radial direction of the turbine, the root is at the tip, the tip is partially curved, or the middle is locally curved. Various shapes of turbine blades have been proposed.

On the other hand, for example, as described in Japanese Patent Application Laid-Open No. Hei 9-1990 / 2004, Japanese Patent Application Laid-Open No. Hei 7-229,044, an increase in rigidity and a damping effect are added, In order to reduce the loss, the tip of the turbine blade may be connected by a connection cover. In this blade connection structure, a torsional moment generated in the direction opposite to the twist of the blade due to the centrifugal force during rotation, that is, an untwist, generates a pressing force between the covers of adjacent blades and makes contact connection. The effect of this torsional return is that the torsion angle of each blade section differs from the root to the tip, so the difference in the centrifugal force perpendicular to the evening bin radial direction acts as a restoring moment on each blade section. Obtained by being pulled to the center of the torsional force of the wing section. Therefore, it is an effective means especially for the one-blade blades having a long blade length and twisting from the root to the tip, such as those used in the last stage of the low-pressure stage of a steam turbine.

On the other hand, for example, blades used in high-pressure and medium-pressure stages of steam turbines, where the blade length is relatively small and the torsion angle is small, and no significant centrifugal force acts on each blade section Therefore, the restoring moment acting during rotation is small. Therefore, in order to apply the same pressing force between the covers to a relatively short wing as to a relatively long wing, it is common practice to incorporate the wing in a state where it has been subjected to torsional deformation in advance during assembly. ing. However, since a special tool is required to pre-twist and install the wings, this installation work is very cumbersome and requires a great deal of labor and time. In addition, when installing the wings, by incorporating the wings in a twisted state, the lr covers of the adjacent wings may rub strongly, and local stress may act on the cover, so use it in high temperature and high pressure parts In such a case, the influence on the creep strength becomes large. Disclosure of the invention

The present invention has been made in view of the above-described conventional problems, and has an improved untwisting effect due to centrifugal force. Even when a relatively short wing is targeted, the connecting force between the covers during rotation is reduced. An object of the present invention is to provide a turbine rotor blade capable of facilitating assembling work, suppressing local concentration of stress, and improving reliability by ensuring sufficient reliability.

In order to achieve the above object, the present invention is directed to a turbine rotor blade having a cover at the tip of a blade, wherein at least the centroid position of the blade section at the tip of the blade is the cross section of the blade at the root of the blade. The profile portion is formed so as to be deviated from the radial line of the turbine extending from the center, and sufficient space is provided between circumferentially adjacent covers according to the positional relationship between the centroid and the radial line and the rotation direction of the profile portion. The inclination direction of the tangential horn of the cover with respect to the axis of the turbine is set so that the pressing force acts. Brief Description of Drawings

Figure 1 is a schematic diagram of a computational model of a turbine rotor blade for analyzing the relationship between the inclination direction of the blade profile and the torsional return.

Fig. 2W: A diagram showing the positional relationship of the centroid of the calculation model shown in Fig. 1 with respect to the radial line in each cross section of the wing.

Fig. 3 is a diagram showing the correlation between the inclination direction of the blade profile and the torsion return obtained using the calculation model in Fig. 1. FIG. 4 is a perspective view illustrating a schematic configuration of the first embodiment of the turbine bucket of the present invention. FIG. 5 is a view of the blade shape of the turbine blade shown in FIG. 4 as viewed from the outer peripheral side in the evening bin radial direction.

FIG. 6 is an external view of the turbine blade shown in FIG. 4 as viewed from the outer peripheral side in the turbine radial direction.

FIG. 7 is an external view of the turbine blade shown in FIG. 4 as viewed from the circumferential direction.

FIG. 8 is a perspective view illustrating a schematic configuration of a second embodiment of the turbine bucket of the present invention. FIG. 9 is an external view of the turbine blade shown in FIG. 8 as viewed from the outer peripheral side in the turbine radial direction.

FIG. 10 is an external view of the turbine blade shown in FIG. 8 as viewed from the circumferential direction.

FIG. 11 is a perspective view illustrating a schematic configuration of a third embodiment of the turbine bucket of the present invention.

FIG. 12 is an external view of the turbine rotor blade shown in FIG. 11 as viewed from the outer peripheral side in the evening bin radial direction.

FIG. 13 is a perspective view illustrating a schematic configuration of a fourth embodiment of the turbine bucket of the present invention.

FIG. 14 is an external view of the turbine rotor blade shown in FIG. 13 viewed from the outer peripheral side in the turbine radial direction.

FIG. 15 is an external view of the fifth embodiment of the turbine blade of the present invention viewed from the outer peripheral side in the turbine radial direction.

FIG. 16 is a perspective view illustrating a schematic configuration of a sixth embodiment of the turbine bucket of the present invention.

FIG. 17 is a perspective view illustrating a schematic configuration of a sixth embodiment of the turbine bucket of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

The evening bin rotor blade according to the present invention is applicable to various fluid machines including, for example, a steam turbine and a gas turbine. In the following, a case of a steam evening bin will be described as an example. First, the principle of the present invention will be described with reference to FIGS.

Generally, centrifugal force causes the blade to untwist due to the deviation of the torsion center position (centroid) of each blade section from the radial line extending from the centroid of the blade root and the difference in centrifugal force acting on each blade section. Occurs. Focusing on this, the inventors of the present application considered that the blade profile was formed by stacking blade cross sections orthogonal to the turbine radial direction line from the root to the tip, and considered the radius of the centroid position of each blade cross section. We analyzed the correlation between the deviation with respect to the direction line and the torsion phenomenon that occurred, and examined the blade profile that would provide a greater effect of torsion.

Figure 1 shows a schematic diagram of the turbine rotor blade calculation model used in this analysis.

In the turbine blade model 100 shown in Fig. 1, the blade cross section 101, which is perpendicular to the evening bin radial direction line R, is stacked from its root portion 102 to its tip portion 103. It is formed. A cover 104 is physically provided at the distal end 103. Each wing cross section obtained by cutting this model 100 at equal intervals from the base part 102 to the tip part 103, and then the respective centroids O and root parts The correlation between the deviation of the radial line R of the turbine extending from the centroid of the blade cross section and the torsional return (untwist angle) generated during rotation was analyzed. However, the shapes of the wing cross sections 101 a to 101 j are almost the same. In this analysis, in order to analyze the untwist acting on the model 100 alone, the tip portion 103 is set to a free end, and there is no binding force by the cover 104. The root part 102 is a fixed end fixed to the mounting part 105 for a turbine disk (not shown).

FIG. 2 is a diagram showing various positional relationships of the centroid O with respect to the radial line R in the wing cross sections 101 a to 101 j.

First, as shown in FIG. 2, cases 1 to 8 were assumed in which the model 100 was inclined in each direction on the coordinates with the steam flow direction X and the circumferential direction Y as axes. However, in the flow direction X, the upstream side is + (plus) and the downstream side is-(minus). In the circumferential direction Y, the back side of the model 100 is + (plus), and the ventral side is-(minus). (See also Fig. 1 3 €>.)

Figure 3 shows the calculation results of the correlation between the wing cross section and the untwist angle in each case 1 to 8. From this calculation result, when the model 100 is tilted upstream in the steam flow direction X, the torsional return angle (untwist angle) increases, and conversely, when the model 100 is tilted downstream in the steam flow direction X, However, there was a tendency for the torsional return angle to decrease (to further twist in the torsional direction of the wing). In particular, the untwisting angle increased when the blade was inclined upstream of the steam and to the back of the blade (case 8). On the other hand, it was found that the reverse torsion (ie, the phenomenon that the blade profile is further twisted in the twisting direction) becomes particularly large when the blade is funneled downstream of the steam and toward the ventral side of the blade (case 5). In addition, the inventors of the present application have performed a similar analysis on a model having different wing cross-sectional shapes. As a result, also in this case, the phenomenon of twisting back in the direction opposite to the twisting direction by inclining to the upstream side, and in the twisting direction by inclining to the downstream side, in particular, causes the blade profile to move upstream and downstream of the steam. It has also been found that when tilted to the side, the untwist angle increases.

The present inventors have found that, based on the above analysis results, it is possible to control the torsional return angle of the turbine blade during rotation by adjusting the inclination of the blade with respect to the radial line of the turbine.

Based on the above findings, each of the embodiments described below sequentially increases the effect of torsional return during rotation, and effectively converts the torsional return to the binding force of the cover, so that adjacent ones can be connected to each other. It is for firmly contacting and connecting. First embodiment

FIG. 4 is a perspective view showing a schematic configuration of a first embodiment of the evening bin rotor blade of the present invention, FIG. 5 is a view of the blade shape of the evening bin rotor blade of FIG. Fig. 6 is an external view of the turbine blade shown in Fig. 4 as viewed from the outer peripheral side in the turbine radial direction, and Fig. 7 is an external view of the turbine blade shown in Fig. 4 as viewed from the circumferential direction.

In FIG. 4, a flat cover 3 is provided at the tip 2 of the turbine blade 1 in the present embodiment. As shown in FIG. 5, the blade profile portion 4 of the evening bin rotor blade 1 is twisted counterclockwise from the root portion 5 toward the tip portion 2 when viewed from the outer peripheral side in the turbine radial direction. The root 5 of the turbine blade 1 is fixed to a rotating shaft (not shown) (turbine disk or a mounting member for this disk). The turbine blades 1 are arranged in the circumferential direction Y,

(Cascade). In the present embodiment, during operation, the turbine blade 1 rotates clockwise when viewed from the upstream side in the steam flow direction X (hereinafter simply referred to as “flow direction X”).

The cover 3 is in contact with the turbine blades 1 adjacent to each other in the circumferential direction Ζ via a contact surface 場合 (including a case where there is a slight gap when viewed microscopically). In the case of the present embodiment, this contact surface Ζ is located on the upstream side of the cover 3 in the flow direction X, and is inclined in the rotation direction toward the downstream side in the flow direction X with respect to the turbine axis Α. are doing. Therefore, the angle す formed by the contact surface Z and the axial spring A clockwise from the contact surface Z when viewed from the outer peripheral side in the turbine radial direction is an obtuse angle.

During rotation, the resting moment M acts on the above-mentioned evening bin rotor blade 1 in the opposite direction to the twisting direction as shown in Fig. 5 and twists back in the profile part 4. Cover 3 attempts to rotate in the direction of action of the restoring moment M when viewed alone. As a result, as shown in FIG. 6, a substantially opposing pressing force F acts on one end surface S, P of the adjacent covers 3, 3 via the contact surface Z, and the adjacent covers 3, 3 are connected to each other. Are contact-connected, and the torsional return of the profile section 4 is restrained. Due to this restraining force, the adjacent covers 3, 3 are firmly contacted and connected at the time of rotation, and each turbine rotor blade 1 of the entire paragraph forms a highly rigid rotor. At this time, the profile portion 4 of the turbine rotor blade 1 in the present embodiment has a pressing force F acting on the contact surface Z in accordance with the inclination direction of the contact surface Z with respect to the axis A based on the analysis result described above. Inclined with respect to radial line R to increase. In other words, in consideration of the blade length of the profile part 4, the inclination direction of the contact surface Z of the cover 3 with respect to the axis A according to the inclination direction of the profile part 4 is obtained so that a desired untwist angle is obtained. Set.

In the present embodiment, as described above, the contact surface Z is inclined in the rotational direction toward the downstream side in the flow direction X, so that as the twist-return action works more strongly, as shown in FIG. Fitting cover 3, The binding force between three becomes stronger. On the other hand, from the analysis results in Fig. 3 above, it is known that when the blade is tilted upstream in the flow direction X, the untwist angle increases. From these, in the case of this embodiment, By inclining the profile part 4 upstream in the flow direction X, the binding force between the covers 3, 3 will be increased.

As can be seen in comparison with the turbine blade parallel to the radial line R from the root to the tip indicated by the two-dot chain line in FIG. 4, the evening bin rotor 1 of the present embodiment has: Flow direction: inclined to the upstream side of X, the centroid O of the wing cross section is located upstream (in the middle of Fig. 4) in the flow direction X with respect to the radial line R extending from the centroid of the root 5. positioned. The stacking line L is a line obtained by connecting the centroids of the respective blade cross sections orthogonal to the radial spring R from the root 5 to the tip 2 of the turbine rotor blade 1. As shown in FIG. 4, in the case of this embodiment, the stacking line L is inclined to the upstream side in the flow direction X with respect to the radial line R, and as shown in FIG. The trailing edge of the root 5 of the part 4 is located upstream of the trailing edge of the tip 2 in the flow direction X.

With the above configuration, according to the present embodiment, the effect of torsional return during rotation can be increased, so that even when the blade length of the turbine rotor blade 1 is relatively short, the cover 3, 3 Can be sufficiently secured. This eliminates the need to assemble the turbine blades by twisting them in advance to supplement the coupling force between the covers of the turbine blades with shorter blade lengths as in the past (or to reduce the amount of torsion added). it can). Therefore, the assembly work can be facilitated, and at the time of assembly, the local stress concentration acting on the covers 3, 3 can be reduced, thereby providing a highly reliable turbine. be able to. Second embodiment

FIG. 8 is a perspective view showing a schematic configuration of a second embodiment of the turbine rotor blade of the present invention. FIG. 9 is an external view of the turbine rotor blade shown in FIG. FIG. 9 is an external view of the evening bin rotor blade shown in FIG. 8 viewed from a circumferential direction. In FIGS. 8 to 10, the same reference numerals are given to the same portions or the portions performing the same functions as those in the preceding drawings, and description thereof will be omitted.

8 and 9, each turbine blade 1 rotates clockwise as viewed from the upstream side in the flow direction X, and the blade profile section 4 has a sunsetting line shown by a two-dot chain line in FIG. 8. Is inclined downstream in the steam flow direction X, as can be seen from comparison with the blade parallel to the radial line R. As shown in Fig. 10, when viewed from the circumferential direction, the root of the profile portion 4 The trailing edge of the portion 5 is located downstream of the trailing portion of the tip 2 in the flow direction X. Thus, in the present embodiment, the swinging line L of the blade is inclined downstream in the flow direction X, and the centroid of each blade cross section is located downstream from the radial line. As shown in FIGS. 2 and 3 above, the wing profile portion 4 rotates in the opposite direction to the above-described first embodiment of the present invention (in the direction opposite to the torsional moment M shown in FIG. 5, Twisted counterclockwise as viewed from the radially outer side. Therefore, when the cover 3 is formed in the same manner as in the first embodiment, no binding force is generated between the adjacent covers 3.

Therefore, in the case of the present embodiment, the contact surface Z of the cover 3 with the cover 3 of the adjacent turbine blade 1 is set in the direction opposite to the rotation direction toward the downstream in the flow direction X with respect to the axis A of the turbine. (In the present embodiment, they are inclined counterclockwise as viewed from the upstream side in the flow direction X). The angle 0 that the contact surface Z forms with the axis A in a counterclockwise direction from the contact surface Z when viewed from the outer peripheral side in the turbine radial direction is an obtuse angle.

The turbine blade 1 of the present embodiment is inclined downstream in the flow direction X, and is further twisted in the twisting direction during rotation. Therefore, by forming the cover 13 as described above, the adjacent cover The opposing pressing forces F are applied between the cover end faces P and S of the cover 3 so that the adjacent covers 3 and 3 can be firmly contacted and connected to each other. Therefore, as described above, assembling work can be facilitated, local stress concentration acting on the cover 3 can be reduced, and a highly reliable evening bin can be provided. Can be. Third embodiment ¾j

Fig. 11 is a perspective view showing a schematic configuration of a third embodiment of the turbine blade of the present invention, and Fig. 12 is an external view of the turbine blade shown in Fig. 11 as viewed from the outer peripheral side in the turbine radial direction. It is. In FIGS. 11 and 12, the same reference numerals are given to the same portions or the portions that perform the same functions as those in the previous drawings, and description thereof will be omitted.

In Fig. 11 and EI 12, each turbine blade 1 moves from the root 5 to the tip 2. And twisted clockwise as viewed from the radially outer side. The turbine blade 1 rotates counterclockwise when viewed from the upstream side in the flow direction X, and its blade profile 4 has a stacking line indicated by a two-dot chain line in FIG. 11 parallel to the radial line R. It is inclined upstream in the flow direction X, as can be seen in comparison with the normal wing. As described above, in the present embodiment, the sucking line L of the blade is inclined to the upstream side in the steam flow direction X, and the centroid of each blade cross section is upstream of the radial line R in the flow direction X. As can be seen from FIGS. 2 and 3, the blade profile 4 twists in the opposite direction to its twisting direction (ie, counterclockwise as viewed from the radially outer side) during rotation. .

Therefore, in the case of the present embodiment, the contact surface Z of the cover 3 is rotated in the direction of rotation toward the downstream side of the steam flow direction X with respect to the turbine axis A (in this embodiment, the upstream of the steam flow direction X). Counterclockwise as viewed from the side). The angle Θ that the contact surface Z forms with the axis A in the counterclockwise direction from the contact surface Z when viewed from the evening bin radial direction is an obtuse angle.

According to this embodiment [according to this embodiment, the turbine rotor blade 1 is inclined to the upstream side in the flow direction X and twists in the direction opposite to the twisting direction during rotation. Therefore, by forming the cover 13 as described above, The mating covers 3, 3 can be firmly contacted and connected. Therefore, the same effect as above can be obtained. Fourth embodiment

FIG. 13 is a perspective view showing a schematic configuration of a fourth embodiment of the turbine rotor blade of the present invention, and FIG. 14 is an external view of the turbine rotor blade shown in FIG. 13 as viewed from the outer peripheral side in the evening bin radial direction. '. In FIGS. 13 and 14, the same reference numerals are given to the same portions or the portions performing the same functions as those in the previous drawings, and the description thereof will be omitted.

In FIGS. 13 and 14, each turbine blade 1 is twisted clockwise from the root 5 to the tip 2 when viewed from the radially circumferential side. The turbine blade 1 rotates counterclockwise as viewed from the upstream side in the flow direction X, and its blade profile 4 has a radial line R indicated by a two-dot chain line in FIG. It is inclined downstream in the flow direction X, as can be seen in comparison with the blade parallel to. Thus, in the present embodiment, the sucking line L is inclined to the downstream side in the flow direction X, and the cross section of each wing is shown in FIG. Since the center 〇 is located on the downstream side of the radial line R, the wing profile section 4 can be further twisted during rotation, that is, clockwise as viewed from the radially outer side, as shown in FIGS. 2 and 3 above. Twist.

Therefore, in the case of the present embodiment, the contact angle Z between the cover 3 and the cover 3 of the turbine blade 1 adjacent to the cover 3 is set to the rotation direction toward the downstream of the steam flow direction X with respect to the turbine axis A. It is inclined in the opposite direction (in this embodiment, clockwise as viewed from the upstream side in the steam flow direction X). The angle す formed by the contact surface Z and the axis A clockwise from the contact surface Z is an obtuse angle when viewed from the outer peripheral side in the evening bin radial direction.

Since the turbine blade 1 of the present embodiment is further twisted in the twisting direction during rotation, forming the cover 3 as described above allows the adjacent covers 3 to be firmly contacted and connected to each other. . Therefore, the same effect as described above can be obtained. Fifth embodiment

FIG. 15 is an external view of a fifth embodiment of the evening bin rotor blade of the present invention viewed from the outer peripheral side in the turbine radial direction. In FIG. 15, the same reference numerals are given to the same portions or the portions performing the same functions as those in the previous drawings, and description thereof will be omitted.

Although not particularly shown in FIG. 15, the turbine blade 1 of the present embodiment is twisted counterclockwise from the root 5 to the tip 2 when viewed from the radially outer peripheral side. It is also assumed that the blade rotates clockwise as viewed from the upstream side in the flow direction X, and that the blade profile portion 4 is inclined downstream in the flow direction X as compared with the blade parallel to the radial line. That is, in the present embodiment, the stacking line of the blade is inclined to the downstream side in the flow direction X, as in the second or fourth embodiment, and the centroid of each blade section is located downstream of the radial direction line. Located on the side. As described above, when the profile part 4 is inclined to the downstream side, from the previous FIGS. 2 and 3, when rotating, the profile part 4 is further twisted in the twisting direction, that is, when viewed from the radially outer side. You will be twisted counterclockwise.

In the case of the present embodiment, the contact surface Z between the covers 1 and 3 is formed linearly. In the case of the example of FIG. 15, the cover 3 rotates counterclockwise in the illustrated state during rotation. And So that the contact surface Z is on the downstream side in the flow direction X with respect to the turbine axis A.

(In Fig. 15, it is inclined toward the left (M) in the direction opposite to the direction of rotation (downward in Fig. 15).

Here, in FIG. 15, the shapes of the facing end surfaces of the covers 3 are different from those of the above-described embodiments. In each of the above embodiments, the opposing end faces of the covers 3 and 3 are formed in a substantially “V” shape. In the present embodiment, the opposing end faces of the covers 1 and 3 and the contact surface Z are extended. It is formed almost linearly. As described above, if the contact surface Z having an appropriate inclination direction is provided so that the twisting of the rotating profile portion 4 is restricted according to the rotation direction and the inclination direction of the evening bin rotor blade 1, the cover 3, 3 The shape of the entire opposing end face is not particularly limited. In such a case, the same effect as above can be obtained.

Needless to say, the same applies to the case where the turbine blade 1 is inclined to the upstream side, and, of course, the rotation direction of the turbine blade 1 is not limited. Sixth embodiment

FIG. 16 is a perspective view illustrating a schematic configuration of a sixth embodiment of the turbine bucket of the present invention. In FIG. 16, the same reference numerals are given to the same portions as those in the previous drawings or the portions performing the same functions, and description thereof will be omitted.

In each of the above-described embodiments, the case where the profile portion 4 is linearly inclined with respect to the radial line R from the root portion 5 to the tip portion 2 has been illustrated and described. However, the present invention is not limited to this. The present invention is applicable even in the case of being inclined. Even when the profile part 4 is inclined in a curved manner, the positional relationship between the inclination direction, that is, the radial center line R of the centroid of each blade section from the root part 5 to the tip end part 2, and the evening bin rotor The same effect can be obtained by setting the inclination of the contact surface Z according to the rotation direction of 1.

Explaining in detail using Fig. 16 as an example, the turbine rotor blade 1 shown in Fig. 16 rotates clockwise when viewed from the upstream side, and the two-dot chain line whose crossing line is parallel to the radial line R. It is inclined upstream in the flow direction X with respect to the turbine blade shown by. The stacking line L of the turbine rotor blade 1 extends from the tip 2 to the root 5 along a radial line R. It draws a curve that converges and is separated from the radial line R from the root 5 to the tip 2 on the upstream side in the flow direction X. Also in this case, as in the first embodiment, the centroid of each blade cross section is located on the upstream side with respect to the radial line R, and the rotation direction of the tarpin rotor blade 1 is clockwise as viewed from the upstream side. From the results shown in FIGS. 2 and 3, the cover 3 tries to rotate clockwise as viewed from the radially outer side. Therefore, as in the first embodiment, if the contact surface Z is provided so as to incline in the rotation direction toward the downstream side in the flow direction X, the contact surface Z can be firmly attached to the contact surface Z by the action of the torsion return of the profile portion 4. A binding force can be generated, and the same effect as described above can be obtained.

Needless to say, for example, when the profile portion 4 in FIG. 16 is curvedly inclined downstream, as shown in FIG. 8 or FIG. 13, the profile portion 4 is opposed toward the downstream in the flow direction X. What is necessary is just to provide the contact surface Z inclined in the rotation direction. Also, contrary to FIG. 16, when the turbine rotor blade 1 rotates counterclockwise as viewed from the upstream side as shown in FIG. What is necessary is just to incline the inclination direction of the surface in the rotation direction (that is, counterclockwise direction).

Also, as shown in FIG. 17, when the stacking line L is shifted from the root portion 5 toward the tip portion 2 with respect to the radial line R, that is, includes the root portion 5 of the wing profile portion 4. The present invention is also applicable to a case where a part is parallel to the radial line R and the part on the tip 2 side is inclined linearly or curvedly. As described above, even when the wing profile part 4 is partially inclined, the inclination direction of the contact surface Z of the cover 3 depends on the inclination direction of the inclined part and the rotation direction of the evening bin rotor blade 1. By setting, the same effect as above can be obtained. In the case of Fig. 17, the inclined portion of the blade profile section 4 is directed toward the upstream side in the flow direction X, and the turbine blade 1 rotates clockwise as viewed from the upstream side in the flow direction X. During rotation, the profile section 4 tries to rotate clockwise when viewed from the outer peripheral side in the turbine radial direction. Therefore, if a contact surface Z inclined in the rotation direction of the turbine rotor blade 1 is provided toward the downstream side of the flow direction X, the binding force between the adjacent covers 3 is secured in the same manner as in the first embodiment. can do. In each of the above embodiments, the turbine blade 1 is moved upstream or downstream in the flow direction X. Was inclined to the downstream side, but as described earlier with reference to Fig. 3, by further inclining in the circumferential direction, the effect of torsional return of the turbine blade 1 can be obtained more effectively. Can be. In other words, when the evening bin rotor blades 1 having substantially the same shape in each blade section are tilted in the upstream direction in the flow direction X, the turbine rotor blades 1 are further tilted rearward to further twist back. Can be obtained. Conversely, when the evening blade 1 is tilted downstream in the flow direction X, the turbine blade 1 is further tilted abdominally to further increase the twisting action in the torsion direction of the profile portion 4. Obtainable. Therefore, in each of the above-described embodiments, by further inclining the turbine blade 1 in the circumferential direction, the binding force between the covers 3 can be more effectively exerted. Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, even if it is a blade | wing with a comparatively short blade | wing length, the contact connection force between adjacent covers can be sufficiently ensured at the time of rotation. This makes it possible to reduce the load on the work of assembling the turbine blade by twisting in advance, thereby improving the assembly workability and preventing the occurrence of local stress concentration at the time of assembly. High turbine blades can be provided.

Claims

The scope of the claims

1. In a turbine bucket having a cover at the tip of the blade for restraining torsion, at least the center of gravity of the blade section at the tip of the blade is at least half a centimeter extending from the center of the blade cross section at the root of the blade.を Form a profile part so that it deviates from the direction line,

According to the positional relationship between the centroid and the radial direction line and the rotation direction of the profile portion, a vial of a contact surface between the covers is provided so that a pressing force acts between the adjacent covers in the circumferential direction. An evening bin rotor blade having a tilt direction set with respect to the axis of the blade.

2. At least the profile center of the blade section at the tip of the blade is located upstream of the radial line extending from the center of the blade section at the root of the blade in the flow direction of the working fluid, and the blade of this profile section A cover provided at the tip end and having a contact surface with a circumferentially adjacent one inclined to the downstream side in the flow direction of the working fluid with respect to the axis of the turbine in the rotation direction of the profiler portion. When

A turbine rotor blade comprising:

3. At least the centroid position of the wing section at the tip of the wing is such that the radial line cfc extending from the centroid of the wing section at the root of the wing is located on the downstream side in the flow direction of the working fluid. The contact surface with the circumferentially adjacent one provided at the tip of the blade is inclined with respect to the axis of the turbine toward the downstream side in the flow direction of the working fluid and in the direction opposite to the rotation direction of the profile portion. With the cover

Turbine rotor blades that have been equipped with.

4. Turbine rotor blades with covers at the blade tip that restrain each other's torsion, rotate clockwise as viewed from the upstream side of the working fluid flow direction, and centroids of each blade section from the root to the tip. At least a portion of a sucking line obtained by connecting the above to a radial line extending from the centroid of the blade root cross section, and inclining to the upstream side in the flow direction of the working fluid; The contact surface of the cover with the cover that is adjacent in the circumferential direction is viewed from the outer peripheral side in the turbine radial direction, so that the angle between the contact surface and the turbine axis in a clockwise direction is an obtuse angle with respect to the turbine axis. Tilted

The feature is the evening bucket.

5. In a turbine blade having a cover at the tip of the blade that restrains each other's torsion, rotate clockwise as viewed from the upstream side in the flow direction of the working fluid, and change the centroid of each blade section from the root to the tip. At least a part of the sucking line obtained by tying is inclined to the downstream side in the flow direction of the working fluid with respect to a radial line extending from the centroid of the blade root cross section,

When the contact surface of the cover with the cover adjacent in the circumferential direction is viewed from the outer peripheral side in the evening bin radial direction, the angle between the contact surface and the axis of the turbine in the counterclockwise direction is an obtuse angle. Inclined to the axis

A turbine blade.

6. Cross section of each blade from the root to the tip, rotating counterclockwise as viewed from the upstream side of the working fluid flow direction, in the turbine blade having a cover at the tip of the blade that restrains each other's twist. Tilting at least a part of the stacking line obtained by connecting the cores with respect to a radial line extending from the centroid of the blade root cross section toward the upstream side in the flow direction of the working fluid;

A turbine blade.

7. A turbine rotor blade with a cover at the blade tip that restrains each other's twist, rotates counterclockwise when viewed from the upstream side in the working fluid flow direction, and shows a cross section of each blade from the root to the tip. At least a part of the sucking line obtained by connecting the cores is inclined to the downstream side in the flow direction of the working fluid with respect to the radial line extending from the centroid of the blade root cross section. Slanted,

The contact surface of the cover with the cover which is adjacent in the circumferential direction is viewed from the outer peripheral side in the turbine radial direction, so that the angle formed with the axis of the turbine clockwise from the contact surface is obtuse. Tilted

A turbine blade.

8. The turbine rotor according to claim 1, wherein a sucking line obtained by connecting centroids of respective blade cross sections from a root portion to a tip portion of the profile portion is curved toward a blade tip portion. A turbine rotor blade formed so as to be separated from a radial line.

9. The turbine rotor according to claim 1, wherein a stacking line obtained by connecting centroids of respective blade cross sections from a root portion to a tip portion of the profile portion is formed from a middle portion in the blade length direction of the profile portion, A turbine rotor blade formed so as to be separated from the radial line toward a blade tip.

10. The turbine according to claim 1, wherein each blade section from the root portion to the tip end of the profile portion is formed to have substantially the same shape. Bucket.

1 1. In a turbine rotor blade having a cover at a blade tip portion that restrains mutual torsion, the adjacent covers are arranged according to the direction of inclination of the contact surface of the cover with respect to the circumferentially adjacent cover with respect to the axis of the turbine. A turbine characterized in that at least the centroid position of the cross section of the blade tip is shifted with respect to the radial line of the turbine extending from the centroid of the cross section of the blade root so that the pressing force acting therebetween increases. Bucket.

1 2. At least the trailing edge of the blade tip is located upstream of the trailing edge of the blade root in the flow direction of the working fluid.

It is provided at the tip of the wing of this profile, and A contact surface of which is inclined with respect to the axis of the turbine toward the downstream side in the flow direction of the working fluid in the rotational direction of the profile portion.

A turbine rotor blade comprising:

1 3. At least the trailing edge of the blade tip is located downstream of the trailing edge of the blade root in the flow direction of the working fluid;

A rotation surface of the profile portion is provided on the blade tip portion of the profile portion, and a contact surface between the profile portion and a circumferentially adjacent one is directed to the downstream side in the flow direction of the working fluid with respect to the axis of the evening bottle. Cover inclining in the opposite direction

A turpentine rotor blade comprising: