JP2005076533A - Turbine blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine blade improving profile efficiency by reducing loss due to shock wave and loss due to deficit of velocity distribution of slip stream. <P>SOLUTION: In a turbine blade having a shape of a following edge 2 in a profile 1 formed with a ventral side edge line 3 and a dorsal side edge line 4, the ventral side edge line 3 is formed with either straight line or curved line having large curvature radius and the dorsal edge line 4 is formed with curved line having smaller curvature radius than curvature radius of the ventral side edge line 3, angle formed at a connection point of an end part of the ventral side edge line 3 and an end part of the dorsal side edge line 4 is formed in roughly perpendicular. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a turbine blade, and more particularly to a turbine blade in which the shape of the trailing edge of the profile (airfoil type) is improved.

  For example, in recent turbine technology fields such as steam turbines and gas turbines, the improvement of the profile efficiency of turbine blades has been reviewed as part of the enhancement of performance improvement.

  Conventionally, the turbine internal loss accounts for about 2/3 of the total turbine loss, and the turbine internal loss is a loss that cannot be ignored.

  Turbine stage loss is roughly classified into profile loss, secondary flow loss, leakage loss, and wetness loss, and development for reducing each loss is underway. The profile loss focused here is a loss due to a velocity distribution defect based on the wake (wake) of the blade. In order to reduce the profile loss, it is important how to reduce the velocity distribution defect. For this purpose, the shape of the blade trailing edge is important, and it is known that the thinner the trailing edge, the smaller the loss.

  However, in reality, the thickness of the trailing edge is limited due to a problem in strength, and the trailing edge shape is a straight line or an arc shape with an allowable limit thickness. Further, in the case of a high Mach number that generates a shock wave, it is necessary to increase the strength of the trailing edge, and considering this point, the trailing edge cannot be thinned.

  For this reason, in turbine blades applied to large-capacity turbines, the improvement in profile efficiency has been reviewed, and although trial and error are repeated, they are currently being searched.

As a technique for improving the trailing edge shape of the profile, for example, as shown in Japanese Patent Application Laid-Open No. 60-122201, it is applied to a small turbocharger, and as shown in, for example, Japanese Patent Application Laid-Open No. 2000-53082. As such, there are those applied to hydrofoil.
JP-A-60-122201 JP 2000-53082 A

  Japanese Patent Application Laid-Open No. 60-122201 applies to a radial type small turbocharger even though it is a turbine blade, and the trailing edge shape of the profile is a back side straight line, a ventral side straight line, and an end face straight line. And the back side straight line and the end face straight line are connected by an arc having a large curvature radius, while the ventral side straight line and the end face straight line are connected by an arc having a small curvature radius.

  However, the one described in Japanese Patent Application Laid-Open No. 60-122201 requires less weight flow rate of the driving fluid to be handled than the large-capacity turbine to which the present application is applied. It is difficult to keep losses due to flow velocity distribution deficiencies low.

  Japanese Patent Application Laid-Open No. 2000-53082 is intended for high-speed boats, and the trailing edge shape is asymmetrical with respect to the center line in the wing front-rear direction. Even if the shape is incorporated in the present application as it is, there is a problem that the loss due to the velocity distribution loss of the wake increases.

  For this reason, in the large-capacity turbine field, it is desired to realize a trailing edge shape that further improves the profile efficiency by reducing the loss based on the shock wave and the velocity distribution defect of the wake, while guaranteeing the strength as before. It was.

  The present invention has been made on the basis of such a background art, and when applied to a large-capacity turbine, the induction of shock waves is reduced, and the velocity distribution deficit of the wake is reduced to further improve the profile efficiency. An object of the present invention is to provide a turbine blade.

  In order to achieve the above-mentioned object, a turbine blade according to the present invention is a turbine blade in which a shape of a trailing edge is formed by a ventral side edge line and a back side edge line in a profile as described in claim 1. The ventral edge line is formed by selecting either a straight line or a curve having a large curvature radius, and the dorsal edge line is formed with a radius of curvature smaller than the curvature radius of the ventral edge line. And the angle of the connection point of the edge part of the said ventral edge line and the edge part of the said back side edge line is formed substantially perpendicularly.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with the ventral edge line and the dorsal edge line, as described in claim 2. In the turbine blade, the ventral edge line is formed by selecting one of a straight line and a curve having a large radius of curvature, and the back side edge line is connected to the end of the ventral edge line via a straight line. On the other hand, the angle of the connection point between this straight line and the end of the ventral edge line is formed substantially perpendicularly.

  Further, in order to achieve the above-described object, the turbine blade according to the present invention has an elliptical back line formed with a curvature radius smaller than the curvature radius of the ventral side edge line as described in claim 3. It is characterized by being a line.

In order to achieve the above object, the turbine blade according to the present invention has a major axis and a minor axis when the major axis is a and the minor axis is b. The ratio a / b of
[Equation 2]
a / b ≦ 5/1
Is set.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with a ventral edge line and a dorsal edge line, as described in claim 5. In the turbine blade, the ventral edge line is formed by selecting one of a straight line and a curve having a large curvature radius, and the dorsal edge line is formed by an implicit function curve.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with a ventral edge line and a dorsal edge line, as described in claim 6. In the turbine blade, the ventral side edge line is formed by selecting any one of a straight line and a curve with a large radius of curvature, and the back side edge line is gradually curved toward the end thereof with a gradually decreasing radius of curvature. It was formed by.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with a ventral edge line and a dorsal edge line, as described in claim 7. In the turbine blade, the ventral edge line is formed by selecting one of a straight line and a curve having a large curvature radius, and the dorsal edge line is formed by a plurality of short straight lines.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with a ventral edge line and a dorsal edge line, as described in claim 8. In the turbine blade, the ventral side edge line is formed by selecting one of a straight line and a curve having a large curvature radius, and the back side edge line is formed by a parametric curve.

  Moreover, in order to achieve the above-mentioned object, the turbine blade according to the present invention forms the shape of the trailing edge of the profile with the ventral edge line and the dorsal edge line, as described in claim 9. In the turbine blade, the ventral side edge line is formed by selecting one of a straight line and a curve with a large curvature radius, and the tip part of the back side edge line is 5% blade height from the end. Each of the root portions having a blade height of 5% from the end portion is formed by selecting one of a straight line and a curve having a large curvature radius, while the remaining blade effective portion is formed by the curvature radius of the ventral edge line. It is formed by a curve having a smaller radius of curvature, and the angle of the connection point between the end of the ventral side edge line and the end of the back side edge line is formed substantially perpendicularly.

  In order to achieve the above-mentioned object, the turbine blade according to the present invention includes a cooling medium outlet in the profile and the shape of the trailing edge of the profile on the ventral side. In the turbine blade formed by an edge line and a back side edge line, the abdomen side edge line is formed by selecting one of a straight line and a curve having a large curvature radius, and the back side edge line is formed by the abdomen. It is formed with a radius of curvature smaller than the radius of curvature of the side edge line, and the outlet is formed on the ventral side edge line side.

  In the turbine blade according to the present invention, in the ventral edge line and the dorsal edge line forming the trailing edge shape of the profile, either the straight line or the curve with a large curvature radius is selected as the ventral edge line, The dorsal edge line is a curve having a smaller radius of curvature than the ventral edge line, and the angle of the connection point between the end of the ventral edge line and the end of the dorsal edge line is made substantially vertical, and driving Since the flow of the fluid is along the ventral edge line and the dorsal edge line and the passage between the blades is made wider, loss due to shock waves and loss due to velocity distribution loss of the wake are reduced. Profile efficiency can be improved.

  Hereinafter, embodiments of a turbine blade according to the present invention will be described with reference to the drawings and the reference numerals attached to the drawings.

  FIG. 1 is a conceptual diagram showing a first embodiment of a turbine blade according to the present invention.

  The turbine blade according to the present embodiment has a ventral side edge line 3 out of the ventral side edge line 3 and the back side edge line 4 that forms the shape of the trailing edge 2 of the profile 1 designed based on the three-dimensional flow pattern analysis. Is formed by selecting one of a straight line and a curve with a large radius of curvature, and the dorsal edge line 4 is a curve with a radius of curvature smaller than the radius of curvature of the ventral edge line 3, for example, an ellipse (an ellipse). 2), the R portion is enlarged and the angle of the connection point J between the end of the ventral edge line 3 and the end of the dorsal edge line 4 is formed substantially perpendicularly as shown in FIG. Is.

Further, a curve with a small curvature radius forming the back side edge line 4, that is, an ellipse (oval) line, where the major axis is a and the minor axis is b, the ratio a / b of the major axis to the minor axis is [Equation 3]
a / b ≦ 5/1
It is set in the range.

However, when the total pressure loss coefficient and strength are taken into consideration, the ellipse (oval) line forming the dorsal edge line 4 has the ratio a / b of the major axis to the minor axis [Equation 4]
a / b ≦ 3/1
Most preferably.

  FIG. 5 is an ellipse major axis / minor axis diagram that determines the ratio between the major axis and minor axis of the ellipse obtained from the total pressure loss coefficient and strength.

  From this diagram, it was found that the intersection of the total pressure loss coefficient and the intensity line, that is, the major axis a of the ellipse was a = 3 and the minor axis b was b = 1.

  FIG. 4 is a loss diagram in which the profile loss of a conventional turbine blade is compared with the profile loss according to the present embodiment. The vertical axis represents the total pressure loss coefficient, and the horizontal axis represents the blade pitch (P). The pitch (P) / blade cord length (c) ratio between the blade length and the blade cord length (c) is employed.

  From this diagram, it can be seen that the backside edge line 4 of the trailing edge 2 according to the present embodiment is formed by an elliptical line compared to the shape of the conventional trailing edge shown in FIGS. It was.

  In particular, when the ratio of pitch (P) / blade cord length (c) is small, the rear edge line 4 of the trailing edge 2 according to the present embodiment is the shape of the conventional trailing edge shown in FIGS. The loss is less than that of the case. When the back edge 4 is formed of an elliptical line, the passage between the wings increases accordingly, and the loss due to the impact and the loss of velocity distribution in the wake is reduced. It is done.

  Thus, in the present embodiment, among the ventral edge line 3 and the dorsal edge line 4 that form the shape of the trailing edge 2 of the profile 1, the ventral edge line 3 is a straight line and a curve with a large curvature radius. Either one is selected and formed, and the back side edge line 4 is formed by a curve smaller than the curvature of the ventral side edge line 3, for example, an elliptical line, while the end of the ventral side edge line 3 and the back side edge Since the angle of the connection point J with the end of the line 4 is made substantially vertical and the passage between the blades is widened, the loss due to the impact and the loss due to the loss of velocity distribution in the wake are reduced to improve the profile efficiency. Can do.

  In this embodiment, the dorsal edge line 4 of the trailing edge 2 is formed by a curve having a relatively small radius of curvature, for example, an elliptical line. However, the present invention is not limited to this example, and an implicit function curve, parametric curve, dorsal edge line is used. 4 may be formed as a curve that gradually decreases the radius of curvature toward the end (connection point J with the ventral edge line) and a line that connects the dorsal edge line 4 with a short straight line. Any of these lines can ensure a wide passage between blades.

  Moreover, although this embodiment made the angle of the connection point J of the edge part of the ventral edge line 3 and the edge part of the back | dorsal edge line 4 substantially perpendicular, it is not restricted to this example, For example, it shows in FIG. In this way, the end of the ventral edge line 3 and the end of the dorsal edge line 4 are connected via the straight line 5 and the angle of the connection point K between the straight line 5 and the end of the ventral edge line 3 is substantially the same. It may be vertical.

  This is effective when setting a reference positioning when creating a profile.

  FIG. 6 is a conceptual diagram showing a third embodiment of a turbine blade according to the present invention.

  The turbine blade according to the present embodiment has a boundary layer in each of a region having a blade height of 5% from the end portion of the tip portion (blade top portion) TIP and a region having a blade height of 5% from the end portion of the root portion (blade root portion) ROT. In this boundary layer, a secondary flow is added and a secondary flow loss occurs, but the region where the blade height is 5% from the end of the tip portion TIP centering on the blade height central portion PCD and Focusing on the fact that there is no disturbance in the flow of the driving fluid in the region of the blade effective portion BEP up to the region where the blade height is 5% at the end of the root portion ROT. As shown in FIG. 7 in which the S portion of the region having a blade height of 5% from the end of the tip 2 of the tip TIP and the region having a blade height of 5% from the end of the root portion ROT is enlarged, as shown in FIG. Each of the side edge lines 4 is either a straight line or a curve with a large radius of curvature. -Option and formed, is obtained by connecting the end portions of the ventral edge line 3 and the back-side edge line 4 at the arc 6.

  Moreover, as shown in FIG. 8 in which the T portion in the region of the blade effective portion BEP of the trailing edge 2 of the profile 1 is enlarged, the turbine blade according to the present embodiment has a straight line and a curve with a large curvature radius. And the dorsal side edge line 4 is formed by a curve with a radius of curvature smaller than the radius of curvature of the ventral side edge line 3, for example, an elliptical line, and the end of the ventral side edge line 3 is formed. The angle of the connection point J between the portion and the end of the back side edge line 4 is formed substantially perpendicularly.

  Thus, in the present embodiment, the back edge line 4 in the region of the blade effective portion BEP of the trailing edge 2 of the profile 1 is formed by, for example, an elliptical line, and the characteristic of the elliptical line, that is, a wide blade-to-blade Since the passage is secured, the profile efficiency can be improved by reducing the loss due to impact and the loss due to the loss of velocity distribution in the wake.

  FIG. 9 is a conceptual diagram showing a fourth embodiment of a turbine blade according to the present invention.

  The turbine blade according to the present embodiment is a cooling blade, and the cooling medium outlet 7 is brought closer to the side of the ventral edge 3 forming the trailing edge 2.

  Thus, in the present embodiment, the cooling medium outlet 7 in the cooling blade is brought closer to the side of the ventral edge line 3 that forms the trailing edge 2, and the back edge line 4 that forms the trailing edge 2 is replaced with an elliptical line, for example. The characteristics of the elliptical line, that is, a configuration that secures a wide passage between blades, can reduce the loss due to the impact and the loss due to the velocity distribution loss of the wake, thereby improving the profile efficiency.

The conceptual diagram which shows 1st Embodiment of the turbine blade which concerns on this invention. FIG. 2 is a partially cutaway enlarged view of an R portion shown in FIG. 1. The conceptual diagram which shows 2nd Embodiment of the turbine blade which concerns on this invention. The loss diagram which contrasted the profile loss of the conventional turbine blade, and the profile loss of the turbine blade which concerns on this invention. The elliptical major axis and minor axis diagram that determines the ratio of the major axis to the minor axis of the ellipse obtained from the total pressure loss coefficient and strength. The conceptual diagram which shows 3rd Embodiment of the turbine blade which concerns on this invention. FIG. 7 is a partially cutaway enlarged view of a portion S shown in FIG. 6. FIG. 7 is a partially cutaway enlarged view of a T portion shown in FIG. 6. The partially notched part enlarged view which shows 4th Embodiment of the turbine blade which concerns on this invention. The conceptual diagram which shows the conventional turbine blade. FIG. 11 is a partially cutaway enlarged view of a U portion shown in FIG. 10. FIG. 12 is a partially cutaway enlarged view showing a conventional trailing edge different from the turbine blade shown in FIG. 11.

Explanation of symbols

1 Profile 2 Trailing edge 3 Ventral edge line 4 Dorsal edge line 5 Straight line 6 Arc 7 Air outlet 10 Profile 11 Trailing edge 12 Ventral edge line 13 Dorsal edge line 14 Straight line 15 Arc

Claims (10)

Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. In addition, the back side edge line is formed with a radius of curvature smaller than the curvature radius of the ventral side edge line, and the angle of the connection point between the end of the ventral side edge line and the end of the back side edge line is determined. A turbine blade characterized by being formed substantially vertically. Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. In addition, the back side edge line is connected to the end portion of the ventral side edge line through a straight line, and the angle of the connection point between the straight line and the end portion of the ventral side edge line is made substantially vertical. A turbine blade characterized by being formed. The turbine blade according to claim 1, wherein a back side edge line formed with a radius of curvature smaller than a curvature radius of the ventral side edge line is an elliptical line. The elliptical line has a ratio of a major axis to a minor axis a / b where the major axis is a and the minor axis is b.
[Equation 1]
a / b ≦ 5/1
The turbine blade according to claim 3, wherein Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. In addition, a turbine blade characterized in that the dorsal edge line is formed by an implicit function curve. Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. The turbine blade is characterized in that the dorsal edge line is formed with a curve having a gradually smaller radius of curvature toward the end portion. Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. And the backside edge line is formed by a plurality of short straight lines. Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. In addition, a turbine blade characterized in that the dorsal edge line is formed by a parametric curve. Among the profiles, in the turbine blade that forms the shape of the trailing edge with the ventral edge line and the dorsal edge line, the ventral edge line is selected by selecting either a straight line or a curve with a large radius of curvature. In addition, among the dorsal side edge line, either the tip portion having a blade height of 5% from the end portion and the root portion having a blade height of 5% from the end portion are either one of a straight line and a curve having a large curvature radius. The remaining wing effective portion is formed by a curve having a curvature radius smaller than the curvature radius of the ventral edge line, and the end of the ventral edge line and the end of the dorsal edge line are selected. Turbine blades characterized in that the angle of the connection point with is formed substantially vertical. In a turbine blade having a cooling medium outlet in a profile and forming the shape of the trailing edge of the profile by a ventral edge line and a dorsal edge line, the ventral edge line is a straight line and a curve having a large radius of curvature. The back edge line is formed with a curvature radius smaller than the curvature radius of the ventral edge line, and the outlet is formed on the ventral edge line side. Turbine blades characterized by that.

Images