JP2000104501A - Turbine moving blade, gas turbine and steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in an incident angle loss even when inflow fluid is deviated from a designed inflow angle by setting a mean surface roughness around the front edge of a moving blade to be rougher than those of a pressure face side and a negative pressure face side and setting the surface roughness around the front edge to be rough enough to cause turbulent flow transition. SOLUTION: In a turbine, a plurality of moving blades 1 are arranged in the circumference direction of a rotor 3, while a stationary blade 6 is arranged on the upstream side of steam 2 matchingly with the moving blades 1. In this case, surface roughness k1 of a predetermined area 18 around the moving blade front edge is set to be higher than surface roughness k2 of the other blade surface part 19. In this way, even if fluid flowing into the moving blade 1 is deviated from a designed inflow angle and flows inward from an undesirable direction from a fluid performance viewpoint, the flow adhering to a stagnation point is forcibly transferred to the turbulent flow by the rough surface part 18 in the front edge and strengthened against the following reverse pressure gradient so as to be hardly peeled off, so that the increase of an incident angle loss can be sufficiently suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine and a gas turbine provided with a turbine blade used for a steam turbine, a gas turbine or a water turbine, and a turbine blade operated by an axial fluid.

[0002]

2. Description of the Related Art In order to improve the efficiency or performance of this kind of turbine, it is important to suppress the separation of fluid generated on the surface of a blade. As a conventional device for suppressing such peeling, for example, as disclosed in Japanese Patent Application Laid-Open No. H8-160601, it is produced by the action of isostatic pressing on a concave pressure surface of an airfoil of a turbomachine. A concave shape having irregularities on the surface, especially where the irregularities are created such that the aerodynamic separation of the irregularities on the surface during operation of the turbine blade is minimized. Some are arranged in the area of the pressure surface. In this case, the other part of the concave pressure surface and the whole of the convex suction surface are formed so that there is no irregular part on the surface.

[0003] In Japanese Utility Model Laid-Open Publication No. Hei 7-35702,
There is disclosed a cascade in which a projection is provided on the upstream side of the fluid from a portion where fluid separation occurs on the blade rear side, and eddies generated by the projection prevent the fluid from separating. In addition, measures to reduce fluid loss due to laminar flow separation are to prevent separation by forcibly transitioning to turbulent flow using a trip wire or vortex generator, mainly on the wing suction side of the aircraft. There is also.

[0004]

In the turbine rotor blade formed as described above, it is possible to suppress an increase in the incident angle loss in the case of a certain movement of the flowing fluid. If the inflowing fluid deviates from the designed inflow angle and flows in a direction that is not preferable in terms of fluid performance, the increase in the incident angle loss cannot be suppressed, and the increase in the incident angle loss cannot always be suppressed. was there.

That is, in the case of a turbine rotor blade having a stage of a stationary blade and a moving blade, the relative inflow angle is determined by a velocity triangle formed by a peripheral speed at each blade height position and an absolute velocity vector of a stationary blade. Of course, the blade shape near the blade leading edge is designed to conform to this velocity triangle, that is, the blade relative inflow angle. However, the flow direction into the leading edge of the moving blade is not constant due to the development degree of the paragraph entrance boundary layer and the secondary flow that develops near the exit wall of the stationary blade affected by this. The corners can deviate from the design speed triangle.

For this reason, when the fluid flowing into the rotor blades deviates from the designed inflow angle and flows in a direction unfavorable in terms of fluid performance, an incident angle loss occurs, and the loss sharply increases as the fluid deviates from the designed inflow angle. I will. Furthermore, when a three-dimensional design vane three-dimensionally stacked in the blade length direction is used as a paragraph configuration, compared to a linearly stacked vane,
There also arises a problem that the outflow angle at the stator blade outlet is deflected, and the relative inflow angle of the moving blade is also deflected.

At the leading edge of the blade, if the intersection point (hereinafter referred to as the blade leading edge) between the blade contour line and the camber line coincides with the stagnation point, the inflow angle of the fluid is defined as an appropriate inflow angle. It is almost equal to the wing-specific inlet angle. At this time, the blade performance is good. The incident angle loss occurs when the inflow angle deviates from the appropriate inflow angle, and as shown in FIGS. 3 and 4, for the swirling inflow (i> 0), the blade suction surface side The boundary layer thickness increases due to the separation occurring near the leading edge, and for backflow inflow (i> 0), the separation occurring near the leading edge on the blade pressure surface side causes an increase in the boundary layer thickness, accompanied by an increase in fluid loss.

Particularly, in the case of a steam turbine impeller, the turning angle of the root airfoil is very large at 120 to 140 degrees, and it is difficult to form an inter-blade flow path as an acceleration flow path. It is very difficult to suppress the increase of the boundary layer thickness due to the separation flow once generated near the leading edge and the development of the boundary layer due to the reverse pressure gradient from the suction surface side throat to the vicinity of the trailing edge when the angle deviates from the inflow angle. It will be.

The present invention has been made in view of the above, and an object of the present invention is to make it possible to prevent the fluid flowing into the moving blade from entering from a design inflow angle that is out of the designed inflow angle and from flowing in a direction unfavorable in fluid performance. An object of the present invention is to provide a turbine rotor blade, a gas turbine, and a steam turbine of this type that can sufficiently suppress an increase in angular loss.

[0010]

That is, in the present invention, in a turbine moving blade operated by a flowing fluid, the average surface roughness near the leading edge of the moving blade is determined by comparing the average surface roughness on the pressure surface side and the average surface roughness on the suction surface side. While forming coarse, the roughness,
In order to achieve the intended purpose, the fluid is formed to have a roughness that causes a turbulent transition.

Further, in a turbine moving blade operated by a flowing fluid, the average surface roughness in the vicinity of the leading edge of the moving blade and in the vicinity of the root leading edge of the moving blade is determined by calculating the average surface roughness on the pressure side and the suction side. It is formed so as to be coarser and to have a roughness that causes a turbulent transition in the flowing fluid.

In this case, the region of roughness that causes the turbulent transition of the flowing fluid may be distributed from the blade root position to a predetermined height in the blade height direction, or may be wider toward the blade root. It was formed so that it might become.

Further, according to the present invention, in a turbine moving blade operated by a flowing fluid, the inflow of the flowing fluid into the moving blade is swollen, and the pressure minimum point generated on the negative pressure surface side when the inflow is caused, and the inflow of the flowing fluid is counteracted. A turbulent transition occurs in the flow fluid that is rougher than the average surface roughness on the pressure surface side and suction surface side and that flows through the blade front edge in the range of the blade leading edge connecting the pressure minimum points generated on the pressure surface side at the time of inflow. The rough surface is provided.

Further, in a turbine rotor blade operated by a flowing fluid, a minimum point of pressure generated on the suction surface side when the flowing fluid flows into the rotor blade in an abrupt manner, In the area of the blade leading edge connecting the pressure minimum points generated on the surface side, the roughness that is rougher than the average surface roughness on the pressure side and suction side and causes turbulent transition in the flowing fluid flowing through the blade leading edge The rough surface is scattered.

Further, in the turbine rotor blade operated by the flowing fluid, a minimum point of pressure generated on the suction side when the inflow of the flowing fluid into the rotor blade is abruptly inflow, and a pressure minimum when the inflow of the flowing fluid flows in the backside. The average surface roughness of the leading edge of the blade connecting the pressure minimum points generated on the surface side is set to 2 to 30 microns, and the average surface roughness of the other surfaces is set to several tenths to several microns. It was done.

Further, according to the present invention, in a gas turbine or a steam turbine provided with a turbine moving blade operated by an axial flowing fluid, the average surface roughness near the leading edge of the turbine moving blade can be reduced on the pressure side and the suction side. Is formed so as to be rougher than the average surface roughness, and the roughness is formed so as to cause a turbulent transition in the axially flowing fluid.

That is, in the turbine rotor blade thus formed, the average surface roughness near the leading edge of the rotor blade is formed to be larger than the average surface roughness on the pressure side and the suction side, and the roughness However, the stagnation point is formed because of the roughness formed to cause turbulent transition in the flowing fluid, that is, the surface roughness near the leading edge of the bucket before laminar separation occurs. The adhering flow is forced into a turbulent transition through this area of surface roughness, so that the boundary layer becomes stronger against the subsequent reverse pressure gradient and is less likely to peel off, so that the fluid flowing into the rotor blades Even when the fluid flows in a direction that is not preferable in terms of fluid performance, an increase in the incident angle loss can be sufficiently suppressed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows the turbine rotor blade and a main part of a turbine provided with the turbine rotor blade. In the figure, 1 is a moving blade (blade), 2 is steam generated by a boiler, 3 is a rotor, 4 is a disk for fixing the moving blade 1 to the rotor 3, 5 is an outer casing, and 6 is steam 2 on the moving blade 1. A guiding vane (nozzle), 7 is an annular inner ring that restrains the inner peripheral end of the stationary blade 6, and 8 is an annular outer ring that fixes the outer peripheral end of the stationary blade 6 to the outer casing 5.

A plurality of moving blades 1 are arranged in the circumferential direction (rotation direction) of the rotor 3, and the stationary blades 6 are arranged upstream of the steam 2 with respect to the moving blade 1 so as to correspond to the moving blades. Is done. Generally, the combination of the moving blade 1 and the stationary blade 6 is referred to as a “turbine stage”. Such turbine stages are arranged in a plurality of stages in the axial direction of the rotor 3. The blade length of the moving blade 1 increases toward the downstream of the flow of the steam 2. The steam 2 guided by the stationary blade 6 is transferred to the rotor 3 via the rotor blade 1.
To rotate. A generator is provided at an end of the rotor 3, and the generator converts rotational energy into electric energy to generate power.

[0020] Turbine stages are classified into "impulse stages" and "reaction stages" in terms of operation principle. The ratio of the heat drop (the amount of change in enthalpy) in the rotor blade 1 to the total heat drop of the turbine stage is called a reaction degree, and a case where the reaction degree is approximately 0.5 is called a reaction stage. On the other hand, the case where the degree of recoil is 0 is called an impulsive stage. Bucket 1
Since the degree of reaction greatly changes from the root of the blade to the tip of the blade, the degree of reaction generally ranges from several to 30% even at the impulse stage. In the impulse stage, most of the pressure difference is converted to velocity energy by the stationary blade 6 and
Torque is applied to the rotor 3 by the impulse acting on the rotor 3. Therefore, the turning angle of the impeller stage rotor blade is larger than the turning angle of the reaction stage rotor blade.

The symbols related to the turbine blade will be described with reference to FIG. In the figure, reference numeral 9 denotes a leading edge of the blade, which is located at the uppermost stream of the airfoil of each cut surface of the bucket 1 with respect to the steam 2. 10 is steam 2
, A trailing edge located at the most downstream of an airfoil of each cutting surface of the rotor blade 1, 11 is a tangent to a camber line at a leading edge 9, 12 is a cascade axis (a circumferential line of the rotor 3), and 13 is The tangent to the camber line at the trailing edge 10 and d indicates the blade width in the rotor axial direction. The contour of the rotor blade can be represented by an envelope formed by connecting multiple circles from the leading edge to the trailing edge of the blade, and the camber line is a line connecting the centers of the circles. Refers to the center line of the wing of a cross section

The moving blade 1 may be twisted from the blade root to the blade tip, or may not be twisted. Here, the angle between the tangent 11 and the cascade axis 12 (blade inlet angle) is ε
₁ , the angle between the tangent 13 and the cascade axis 12 (blade exit angle) is ε ₂
Then, the turning angle ε is expressed by ε = 180− (ε ₁ + ε ₂ ). With respect to the direction of the steam 2 flowing into the bucket 1, when i = + i with respect to the angle of attack i = 0 degrees, it is referred to as belly flow, and when i = -i, as back flow. Appropriate inflow angle for airfoil of any cut surface (minimum point of airfoil loss)
Is empirically around i = 0 degrees.

FIGS. 3 and 4 are enlarged views of the vicinity of the leading edge of the turbine rotor blade, and show schematic views of a flow field flowing into the rotor blade. FIG. 3 shows the case of a belly flow.
Sp in the figure represents a stagnation point. From this stagnation point Sp, a boundary layer develops on the suction side and the pressure side, respectively. The steam turbine high-intermediate pressure stage, Reynolds number relative to the rotor blade chord length on the order of about 10 ⁶ to 10 ^8. In this Reynolds number range, the boundary layer on the blade surface is considered to be in a turbulent state in almost all regions except the vicinity of the blade leading edge. Therefore, when entering at an appropriate inflow angle, the boundary layer takes a development process in which the laminar flow state near the leading edge of the blade gradually becomes unstable, and finally transitions to turbulent flow.

In the case of the bellows inflow as shown in FIG. 3, a stagnation point Sp is formed slightly downstream of the blade front edge on the pressure side, and the flow toward the blade suction side accelerates through the blade front edge and passes therethrough. Point X
At s, the flow velocity becomes maximum (the pressure becomes a minimum value), then rapidly decelerates, and the fluid near the wall surface peels off from the separation point 17 to form a separation vortex 16. At this time, the thickness of the boundary layer increases with the separation.

On the other hand, in the case of a backflow inflow as shown in FIG. 4, a stagnation point Sp is formed slightly downstream of the blade leading edge on the suction side, and the flow toward the blade pressure surface accelerates through the blade leading edge and passes therethrough. Then, at the point Xp, the flow velocity becomes a maximum (the pressure becomes a minimum value), then rapidly decelerates, and the fluid near the wall surface peels off from the separation point 17 to form a separation vortex 16. At this time, similarly to the case of FIG. 3, the thickness of the boundary layer increases with the separation.

Next, the flow fields of FIGS. 3 and 4 will be described from the viewpoint of the blade surface pressure distribution. FIG. 5 and FIG. 6 show the blade surface pressure distribution in which the blade surface static pressure is made dimensionless by the inlet total pressure. FIG. 5 shows the case of inflow into the wing, in which the pressure is minimized at the aforementioned Xs on the blade negative pressure side due to the rapid acceleration from the stagnation point Sp, and then the separation occurs due to the reverse pressure gradient. FIG. 6 shows the case of backflow inflow. On the blade pressure surface side, the pressure is minimized at the above-mentioned Xp due to the rapid acceleration from the stagnation point Sp, and then the separation occurs due to the reverse pressure gradient. In either case, once the separation occurs, the boundary layer thickness increases, so that the fluid loss increases.

As described above, in order to suppress the fluid loss due to the laminar flow separation near the leading edge, some improvement is made to the boundary layer developed on the wing surface before the separation point 17 shown in FIGS. There is a need. In the present invention, the surface roughness near the leading edge of the blade before laminar flow separation occurs, a predetermined amount of roughness,
That is, the roughness that causes a turbulent transition in the flowing fluid (of course,
(The surface roughness is larger than the average surface roughness of the blade abdomen and the blade back), whereby the flow adhering to the stagnation point Sp passes through this surface roughness region and forcibly transitions to turbulence. , And becomes difficult to peel off.

In the case of the steam turbine high-to-medium pressure stage, the blade surface finish of the rotor blade portion exposed to the working fluid has an average surface roughness R
a (hereinafter abbreviated as surface roughness) is a mirror finish of several tenths to several microns.

FIG. 7 is an enlarged view of the vicinity of the leading edge of the blade section of the rotor blade of the present invention. As shown in this figure, the surface roughness is k1 (micron) in a predetermined range 18 near the blade leading edge, and the surface roughness is k2 (micron) in the other blade surface portions 19. ing. The relationship between k1 and k2 is k
1> k2, the surface roughness near the leading edge of the bucket becomes larger. In the drawings described from FIG. 7 onward, a small arc shape seen near the front edge distinguishes the region with the surface roughness k1 from the others.

FIGS. 8 and 9 are a perspective view and a sectional view of a blade according to the present invention. In the figure, the hatched portion 18 near the leading edge corresponds to the portion having the surface roughness k1 and the other wing surface portions 19 correspond to the portion having the surface roughness k2.
20 is a line connecting the leading edge 9 in the wing height direction, and 21 is a trailing edge 10
, A line connecting the blades in the blade height direction, and H represents the blade length. In the present invention, the surface roughness is k1 in a predetermined range 18 near the leading edge of the moving blade over the entire blade height direction, and the surface roughness of the other blade surface portion 19 is k2. . However, the relationship between k1 and k2 is k1> k2.

FIGS. 10 to 13 are sectional views of the moving blade shown in FIG. FIG. 10 is an enlarged view of the vicinity of the leading edge of the bucket according to the present invention. Here, the range 18 in which the surface roughness is k1 is continuously distributed on both the pressure side and the suction side with the front edge 9 interposed therebetween.
are in the range of p and Ls. Other wing surface part 19
Has a surface roughness of k2.

FIG. 11 shows another example near the leading edge of the bucket according to the present invention. Here, the range 18 in which the surface roughness is k1 except for the very vicinity of the leading edge 9,
It is distributed in two places on the pressure surface side and the suction surface side with the leading edge 9 interposed therebetween, and lies within the range of Lp and Ls from the leading edge 9 respectively. The surface roughness of the other wing surface portions 19 is k2. In this figure, a range 18 where the surface roughness is k1
Is one at the pressure surface side and one at the suction surface side, but may exist at a plurality of positions within the range of Lp and Ls from the leading edge 9.

FIG. 12 is an enlarged view of the vicinity of the leading edge of the bucket according to the present invention. Here, the surface roughness consists of a single roughness k 1 and is located at the leading edge 9. Single roughness k1
In the other range 19, the surface roughness is k2.

FIG. 13 is an enlarged view of the vicinity of the leading edge of the bucket according to the present invention. Here, the surface roughness is made up of a single roughness k1, and one surface roughness exists from the leading edge 9 in the range of Lp on the pressure surface side and Ls on the negative pressure surface side. In the range 19 other than the single roughness k1, the surface roughness is k2. The single roughness k1 shown in FIG. 12 and FIG.
A protrusion such as a tripping wire may be used.

FIGS. 14 and 15 are enlarged views of the vicinity of the leading edge of the bucket according to the present invention. Here, the range 18 in which the surface roughness is k1 is the range of Ls from the leading edge 9 to the negative pressure surface side in FIG. 14, and the range Ls from the leading edge 9 to the pressure surface side in FIG.
There is one each in the range of p. The surface roughness of the other wing surface portions 19 is k2. In the present embodiment, the case of FIG. 14 is particularly effective in improving the loss characteristics on the belly side, and the case of FIG. 15 is particularly effective in improving the loss characteristics on the back side.

In FIGS. 14 and 15, the surface roughness is k1
Range 18 has a distribution length, but may consist of a single roughness k1 such as a tripping wire.

In FIGS. 7 and 9 to 15, the surface roughness is an arc-shaped cross section having a diameter of k1, but if the height of the roughness is k1, any shape of roughness may be used. good. If the height k1 of the surface roughness is about 2 to 30 microns, the effect of the present invention can be most expected. Although the case where the present invention is applied to the steam turbine high- and medium-pressure stage moving blades has been described above, the technical idea of the present invention can be applied to a steam turbine low-pressure stage moving blade as it is. In this case, the Reynolds number relative to the rotor blade chord length from about 10 ⁵ to
A 10 ⁶ order of. Even in this Reynolds number range,
It is considered that the boundary layer on the blade surface is in turbulent state in most areas except near the leading edge of the blade. Therefore, the boundary layer thickness that develops on the surface of the low-pressure stage blade is larger than that of the high- and medium-pressure stage blade. The effect of the invention can be expected most.

FIGS. 16 and 17 are perspective views of a bucket according to the present invention. The difference from FIG. 8 is that the range 18 in which the surface roughness is k1 is distributed from the root to a predetermined distance h in the blade length direction. This embodiment is an example in which the present invention is focused on a predetermined distance h from the root where the boundary layer and the secondary flow develop, and the present invention is applied to this range. Further, in FIG. 16, the range 18 where the surface roughness is k1 is shown.
17 is constant in the blade height direction.
As shown in the figure, at a position at a predetermined distance h from the root, the blade height is such that the chord direction range of the surface roughness is zero, increases toward the blade root, and becomes maximum at the blade root. It may have a directional distribution.

In the embodiment shown in FIGS. 16 and 17, the blade height direction range h where the surface roughness is k1 is about 20 to 50 mm for a moving blade such as a steam turbine. Also,
In the range in which the surface roughness k1 is distributed in each section of the moving blade, the embodiment shown in FIGS. 10 to 15 can be applied as it is.

In all the embodiments described above, if the moving blade of the present invention is applied to a plurality of steam turbines having different turbine outputs and steam conditions (flow velocity, temperature, pressure, etc.), the surface near the leading edge of the moving blade can be obtained. By making the roughness coarser than the surface roughness of other blade surface parts, even if the fluid flowing into the moving blade deviates from the designed inflow angle and flows from an unfavorable fluid performance direction, the increase in incident angle loss is suppressed. The turbine blade can be provided.

FIG. 18 shows a relationship diagram (incident angle characteristic diagram) between the airfoil loss coefficient and the incident angle. In the drawing, a large turning angle generally indicates a blade root side having a large turning angle ε, and a small turning angle generally indicates a blade tip side having a small turning angle ε. Further, the conventional example refers to a moving blade having a surface finish of several tenths to several microns of every tenths where the surface roughness of the moving blade is everywhere, and the present invention refers to the moving surface of the moving blade near the leading edge. A rotor blade having a surface finish of about 2 to 30 microns and a surface roughness of other blade surfaces of several tenths to several microns. According to FIG. 18, in the present invention, the change of the airfoil loss coefficient indicating the degree of the airfoil loss is flat when the incident angle i is in the range of −i to + i, as compared with the conventional example. That is, in the rotor blade 1 of the present invention, even when the inflow direction of the steam 2 deviates from the appropriate inflow angle (i ≒ 0), the airfoil loss does not increase sharply.

Hereinafter, another embodiment of the present invention will be described. FIG. 19 shows a case in which the technical concept of the present invention is applied to a steam turbine component including high, middle, and low pressure stages. This figure shows only the main components. In the figure, 22 indicates a high-pressure turbine component, 23 indicates a medium-pressure turbine component, and 24 indicates a low-pressure turbine component. 25 is a turbine shaft, 26 is a boiler, 27 is a generator, 28 is a condenser, 29 is steam supplied from the boiler to the high pressure first stage, 30 is steam supplied from the high pressure turbine to the boiler, 31 is medium pressure from the boiler. Reheat steam supplied to the turbine, 32 is steam supplied from the medium-pressure turbine to the low-pressure turbine, 33 is steam supplied from the low-pressure turbine to the condenser, and 34 is water supplied from the condenser to the boiler. It is shown.

The blades constituting each turbine stage in the high-pressure turbine component 22 or the medium-pressure turbine component 23 are indicated by shaded portions 35. Similarly, blades constituting each turbine stage in the low-pressure turbine component 24 are indicated by 36 and are shaded. In the high-to-medium pressure stage of the steam turbine, the Reynolds number based on the blade chord length is about 10 ⁶
Since the order of about 10 to 10 ^{8 and} the order of about 10 ⁵ to 10 ⁶ at the low pressure stage, the boundary layer thickness developed on the moving blade surface is smaller in the moving blade 35 in the high-medium pressure turbine. Accordingly, the height k1 of the moving blade surface roughness (range 18) is lower in the moving blade 35 in the high / medium pressure turbine than in the moving blade 36 in the low pressure turbine.

In the above embodiment, the turbine rotor blade is shown by taking a steam turbine as an example. However, the technical idea of the present invention can be similarly applied to other turbine rotor blades such as a gas turbine and a water turbine. .

FIG. 20 shows a plot of the surface roughness k1 near the leading edge of the moving blade against the Reynolds number when the present invention is applied to a steam turbine, a gas turbine, and a water turbine. As described above, in the steam turbine, the surface roughness near the leading edge of the high- and medium-pressure turbine blade is smaller than that of the low-pressure turbine. The gas turbine and the water turbine are operated in the Reynolds number range shown in the diagram. Therefore,
The effect of the present invention can be most expected if the surface roughness k1 of the gas turbine blade and the runner near the runner leading edge is in the order of several tens of microns to 100 microns. In particular, k1 is preferably about 15 to 50 microns for a gas turbine blade, and about 10 to 100 microns for a water turbine runner.

In the above-described embodiment of the present invention, the turbine blade in which the trailing edge line 21 is linearly stacked is shown. However, the technical idea of the present invention is referred to as a Bow blade or a compound-lean blade. The same effect can be obtained with a curved turbine rotor blade that is three-dimensionally stacked in the blade height direction.

[0047]

As described above, according to the present invention, a portion having an average surface roughness greater than the average surface roughness of the blade abdomen and the blade back is provided near the leading edge of the moving blade, and this roughness is reduced. Even if the fluid flowing into the rotor blades deviates from the design inflow angle and flows in a direction unfavorable for fluid performance, Due to the rough surface at the edge, the flow attached to the stagnation point is forced to make a turbulent transition, and the boundary layer becomes more resistant to the subsequent reverse pressure gradient and is less likely to peel off. This kind of turbine blade that can be suppressed can be obtained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing a main part of a turbine provided with a turbine rotor blade of the present invention, and a perspective view showing one embodiment of the turbine rotor blade.

FIG. 2 is a cross-sectional plan view showing one embodiment of the turbine blade of the present invention.

FIG. 3 is a schematic view of a flow field near a leading edge in the case of a conventional inflow of turbine blades.

FIG. 4 is a schematic view of a flow field near a leading edge in the case of a backflow inflow of a conventional turbine blade.

FIG. 5 is a blade surface pressure distribution diagram in the case of a bellows inflow of a conventional turbine blade.

FIG. 6 is a blade surface pressure distribution diagram in the case of a backflow inflow of a conventional turbine blade.

FIG. 7 is a schematic diagram of the surface roughness near the leading edge of the turbine blade according to the present invention.

FIG. 8 is a perspective view of a turbine bucket according to the present invention.

FIG. 9 is a plan view of FIG.

FIG. 10 is a schematic diagram of a surface roughness near a leading edge showing another embodiment of the turbine bucket according to the present invention.

FIG. 11 is a schematic diagram of a surface roughness near a leading edge showing another embodiment of the turbine rotor blade according to the present invention.

FIG. 12 is a schematic diagram of the surface roughness near the leading edge showing another embodiment of the turbine bucket according to the present invention.

FIG. 13 is a schematic diagram of a surface roughness near a leading edge showing another embodiment of the turbine bucket according to the present invention.

FIG. 14 is a schematic diagram of the surface roughness near the leading edge showing another embodiment of the turbine bucket according to the present invention.

FIG. 15 is a schematic diagram of a surface roughness near a leading edge showing another embodiment of the turbine blade according to the present invention.

FIG. 16 is a perspective view showing another embodiment of the turbine bucket of the present invention.

FIG. 17 is a perspective view showing another embodiment of the turbine blade of the present invention.

FIG. 18 is a relationship diagram between an airfoil loss coefficient of a turbine rotor blade and an incident angle.

FIG. 19 is a system diagram showing a steam turbine plant provided with a turbine blade of the present invention.

FIG. 20 is a graph showing the relationship between the surface roughness near the blade leading edge and the Reynolds number according to the present invention.

[Explanation of symbols]

1 ... rotor blade, 2 ... steam, 3 ... rotor, 4 ... disk, 5 ...
Outer casing, 6 ... Static blade, 7 ... Inner ring, 8 ... Outer ring, 9 ...
Leading edge, 10 ... Trailing edge, 11 ... Tangent line of camber line at leading edge, 12 ... Cascade line, 13 ... Tangent line of camber line at trailing edge, 14 ... Inflow direction of working fluid, 15 ... Outer edge of boundary layer, 16 ... Peeling vortex, 17 ... Peeling point, 18 ... Blade surface with average surface roughness Ra of k1 (micron), 19 ... Blade surface with average surface roughness Ra of k2 (micron), 20 ... Leading edge 9 in blade height direction , A line connecting the trailing edge 10 in the blade height direction, 22 ... a high-pressure turbine component, 23 ...
Medium pressure turbine component, 24 ... low pressure turbine component, 25 ... turbine shaft, 26 ... boiler, 27 ...
Generator, 28 ... condenser, 29: steam supplied from the boiler to the high pressure first stage, 30 ... steam supplied from the high pressure turbine to the boiler, 31 ... reheat steam supplied from the boiler to the medium pressure turbine, 32 ... Steam supplied from the medium pressure turbine to the low pressure turbine, 33 ... Steam supplied from the low pressure turbine to the condenser, 34 ... Feed water supplied to the boiler from the condenser, 3
Reference numeral 5: a moving blade constituting each turbine stage in the high-pressure turbine component 22 or the intermediate-pressure turbine component 23; 36, a moving blade constituting each turbine stage in the low-pressure turbine component 24; Sp: stagnation point; Xp: pressure surface side blade A point where the flow velocity becomes maximum (the pressure becomes a minimum value) near the leading edge, Xs: a point where the flow velocity becomes a maximum (the pressure becomes a minimum value) near the leading edge of the suction surface side blade, Lp: a distance between the leading edge 9 and Xs, Ls ... distance between the leading edge 9 and Xp, k1 ... roughness (micron) with an average surface roughness of 18 and k2 ... roughness (micron) with an average surface roughness 19.

Continued on the front page (72) Inventor Yoshio Kano 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in the Electric Power & Electronics Development Division, Hitachi, Ltd. 3G002 BA02 BB01

Claims (9)

[Claims] 1. A turbine blade operated by a flowing fluid, wherein an average surface roughness near a leading edge of the blade is formed larger than an average surface roughness on a pressure side and a suction side, and the roughness is reduced. A turbine rotor blade formed to have a roughness that causes a turbulent transition in a flowing fluid. 2. A turbine blade operated by a flowing fluid, wherein an average surface roughness near a leading edge of the rotor blade and near a root leading edge of the rotor blade is determined by calculating an average surface roughness on a pressure side and a suction side. A turbine rotor blade characterized by being formed coarser and having a roughness that causes a turbulent transition in a flowing fluid. 3. The turbine rotor blade according to claim 1, wherein the region of roughness causing the turbulent flow transition in the flowing fluid is distributed from a blade root position to a predetermined height in a blade height direction. 4. The turbine rotor blade according to claim 1, wherein a region of roughness that causes a turbulent transition in the flowing fluid is formed to be wider toward a blade root side. 5. A turbine blade operated by a flowing fluid, wherein a minimum point of pressure generated on a suction surface side when the flowing fluid flows into the moving blade in a bellows flow, and a pressure minimum when the flowing fluid flows in a backflow. In the area of the blade leading edge connecting the pressure minimum points generated on the surface side, it is rougher than the average surface roughness on the pressure side and suction side,
A turbine rotor blade having a rough surface that causes a turbulent flow transition in a fluid flowing through a leading edge of the blade. 6. A turbine blade operated by a flowing fluid, wherein a minimum point of pressure generated on a suction surface side when the flowing fluid flows into the moving blade in a bellows flow, and a pressure minimum when the flowing fluid flows in a backflow direction. In the area of the blade leading edge connecting the pressure minimum points generated on the surface side, it is rougher than the average surface roughness on the pressure side and suction side,
A turbine rotor blade characterized in that a rough surface having a roughness that causes turbulent flow transition is scattered in a flowing fluid flowing through a leading edge of the blade. 7. A turbine blade driven by a flowing fluid, wherein a minimum point of pressure generated on the suction side when the flowing fluid flows into the moving blade in a bellows flow, and a pressure minimum when the flowing fluid flows in a backflow direction. The average surface roughness of the leading edge of the blade connecting the pressure minimum points generated on the surface side is set to 2 to 30 microns, and the average surface roughness of the other surfaces is set to several tenths to several microns. A turbine blade characterized by the following. 8. A gas turbine provided with a turbine moving blade operated by an axial flowing fluid, wherein an average surface roughness near a leading edge of the turbine moving blade is larger than an average surface roughness on a pressure side and a suction side. A gas turbine, wherein the gas turbine is formed to have a roughness that causes a turbulent transition in an axial flowing fluid. 9. A steam turbine having a turbine moving blade operated by an axial flowing fluid, wherein an average surface roughness near a leading edge of the turbine moving blade is larger than an average surface roughness on a pressure side and a suction side. A steam turbine, wherein the roughness is formed so as to cause turbulent transition in an axial flowing fluid.