JP3626899B2 - End wall structure between turbine blades - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an end wall structure between turbine blades, and has a structure that improves efficiency by accelerating the fluid flow of the boundary layer flow of the blade end walls to make the flow uniform.
[0002]
[Prior art]
FIG. 5 is a blade shape of a conventional steam turbine, gas turbine, or the like, showing a stationary blade, where (a) is a sectional shape of the blade, and (b) is an AA sectional view in (a). In both figures, 50 is a turbine stationary blade, 51 is a throat between adjacent blades, 52 is an end wall of the blade, 53 is a suction surface of the blade, and 54 is a pressure surface of the blade. Fluid in between the blades of the turbine stationary blade 50 is accelerated up to the throat 51 while changing the angle at which flows along the shape of the wing. At this time, a pressure gradient is generated between the blades to balance the centrifugal force generated according to the curvature of the mainstream streamline 60. However, the slow fluid inside the boundary layer that develops on the end wall 52 has a centrifugal force sufficient to balance the pressure gradient from the pressure surface 54 toward the suction surface 53, and therefore the flow direction is larger than the main flow 60. A so-called secondary flow 61 is generated. Due to the secondary flow 61, the flow angle distribution in the blade height direction and the axial flow velocity distribution at the blade row outlet are non-uniform, causing the efficiency of not only the stationary blade but also the downstream moving blade to decrease. .
[0003]
[Problems to be solved by the invention]
As described above, in the conventional turbine blade, the secondary flow 61 having a flow direction different from that of the main flow 60 is generated in the end wall 52 between the blades, and this is the flow angle distribution in the blade height direction at the blade row outlet. And the velocity distribution is non-uniform, reducing the efficiency, and the flow turbulence at the stationary blade outlet also affects the performance of the lower fluid blade. There was a strong demand for measures to improve efficiency by improving the flow.
[0004]
Therefore, the present invention provides an end wall structure between the turbine blades adopting the shape of the blade tip wall surface that improves the efficiency of the flow by suppressing the generation of the secondary flow by devising the shape of the turbine blade end wall. It was made as an issue.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides the following means (1) to ( 2 ).
[0006]
(1) The inter-blade hub side wall surface of the turbine stationary blade has a protrusion shape having a peak between the leading edge and the trailing edge, and the peak of the protrusion is a curved surface, and the locus of the apex of the curved surface Forms a straight line in a direction perpendicular to the turbine axis, and the position of the straight line is set to the position of a throat formed between adjacent stationary blades, and the height of the protrusion is 2.6% of the blade height. end wall structure between the turbine blades, characterized by the following.
[0007]
(2) The inner wall surface of the inner surface of the blade between the blades having a shroud at the tip and the base portion fixed to the platform on the hub side has a protrusion shape having a top portion between the leading edge and the trailing edge. top of a curved shape and the trajectory of the vertex of the curved surface to form a straight line in a direction orthogonal to the turbine axis, Ru is set to further position the throat position of the straight line formed between the rotor blades adjacent In addition to the protrusion shape of the shroud, the protrusion shape is also formed on the outer wall surface of the platform outer end, and the height of the protrusion shape is 2.6% or less of the blade height. End wall structure between turbine blades.
[0008]
In (1) of the present invention, the flow of the fluid accelerates along the protrusion shape due to the protrusion shape of the hub side end surface between the stationary blades, and the speed of the hub side end wall boundary layer fluid increases accordingly. Therefore, the secondary flow can be suppressed. Then , the height of the protrusion shape is set to 2.6% or less of the height of the blade, and further, the position of the apex of the protrusion shape in the flow direction is matched with the throat for optimization. This suppresses the generation of a secondary flow on the hub side end wall surface between the stationary blades, and improves the efficiency by making the flow uniform at the stationary blade outlet.
[0009]
In (2) of the present invention, since the protrusion shape is provided on the inner wall surface of the shroud at the tip of the rotor blade, the flow of the rotor blade shroud wall surface is accelerated by this protrusion shape, and the velocity of the shroud side end wall boundary layer fluid is increased. Ru can be suppressed secondary flow generated near the shroud side wall surface.
[0010]
Further , in addition to the inner wall surface of the inner surface of the shroud at the tip of the moving blade, a protrusion shape is also formed on the inner wall surface of the inner surface of the platform of the moving blade. The secondary flow generated in the vicinity of the both end wall surfaces of the platform can be suppressed. Also, the height of the collision force shapes and 2.6% or less of the height of the blade, and further matches the position of the vertex of the flow direction of the projection shape in the throat, and measure the optimization. As a result, the secondary flow is suppressed on the shroud at the tip of the rotor blade and the wall surfaces of both ends of the platform, and the flow is uniform at the outlet of the rotor blade, thereby improving efficiency.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. 1A and 1B show a turbine blade end wall structure according to a first embodiment of the present invention, in which FIG. 1A is a side view of the whole, FIG. 1B is a perspective view of a blade end wall, and FIG. The blade is shown and applied to a turbine having a rotating body such as a steam turbine, a gas turbine, and a compressor. In both figures, 10 is a stationary blade, and the stationary blade 10 is fixed between the hub side end wall 11 and the casing 12.
[0012]
The stationary blade of the first embodiment has a blade height S and a blade axial cord length C, and the gas flow direction G of the hub side end wall 11 has X ₁ , the height of both the top portion to have a top portion 14 to the dimensions and a position of X ₂ are the projection wall 13 of the H are formed. The top portion 14 is located at X ₁ and X ₂ from the blade tip, respectively, and as shown in FIG. 1 (b), the locus of the vertex is formed in a straight line in the direction orthogonal to the axis, and the height H is maintained from the bottom surface of the hub. Is formed.
[0013]
2A and 2B are views showing the shape of the protruding wall described above. FIG. 2A is a plan view of the hub side end wall, and FIG. 2B is a sectional view thereof. The top 14 as shown in (a) is formed in a direction P perpendicular to the axial direction R of the turbine, is formed at a position away from both of the wing X _1, X _2, the top 14 is formed into a smooth curved surface ing. The positions of X ₁ and X ₂ are determined so that the locus of the vertex 14 is a straight line that coincides with the position of the throat 51, and the height H is set to about 2.6% or less of the blade height S.
[0014]
In the end wall structure between the turbine blades of the first embodiment of the above configuration, the protrusion wall 13 having a height H is provided on the surface of the hub side end wall 11 between the blades, and the fluid along the wall surface is locally provided on the protrusion wall 13. By accelerating along the smooth surface, the velocity of the boundary layer fluid V of the hub side end wall 11 increases, and the conventional secondary flow can be suppressed.
[0015]
The height H of the projection wall 13 is set to such a height that the flow does not separate, and the position of the projection in the flow direction X ₁ , so that the top portion 14 comes to the position of the throat 51 in consideration of the balance with the throat position. to determine the X _2, which measure the optimization. In the first embodiment, the height H of the projection wall 13 is set to a limit of about 2.6% of the blade height as described above.
[0016]
FIG. 3 is a side view of an end wall structure between turbine blades according to a study example studied in connection with the present invention , and is an example applied to a moving blade. In the figure, reference numeral 20 denotes a moving blade, a tip shroud 22 is attached to the tip, and the base is fixed to the platform 21 on the hub side. The shroud type moving blade 20 has a blade height S, a blade axial code length C, and a tip 24 having a height H at a position where the dimensions Y ₁ and Y ₂ are in the gas flow direction G of the tip shroud 22. A protruding wall 23 is formed. The dimensions Y ₁ and Y _{2 of} the projection wall 23 and the position of the top 23 are the same as the positional relationship described in FIG. 2, and the top 24 is a top formed by a smooth curved surface, and is a straight line perpendicular to the axial direction. It is formed on the top and its position matches the position of the throat 51. The height H is set with 2.6% of the blade height S as an upper limit.
[0017]
In the above examination example , in the rotor blade 20, the protruding wall 23 having a height H is formed on the tip shroud 22, and the fluid along the wall surface is locally accelerated along the smooth surface of the protruding wall 23. The velocity of the end wall boundary layer fluid on the tip shroud 22 side is increased, and the secondary flow generated near the end wall on the tip shroud 22 side can be suppressed.
[0018]
It is necessary to optimize the height H in consideration of the balance with the throat position in consideration of the balance with the throat position. Therefore, in the present study example , the height of the projection is limited to 2.6% of the blade height S as described above, and the position in the flow direction is the locus of the top 24 of the projection wall 23 as described above. Is set to a straight line shape that matches the throat part.
[0019]
FIG. 4 is a side view of an end wall structure between turbine blades according to a second embodiment of the present invention, which is an example applied to both a blade shroud and a platform having a tip shroud. In the figure, reference numeral 30 denotes a moving blade, a tip shroud 32 is attached to the tip, and the base is fixed to the platform 31 on the hub side. This shroud type moving blade 30 has a blade height S and a blade axial code length C, and the dimensions Y ₁ and Y _{2 in} the gas flow direction G on the end wall surface of the tip shroud 32 are the same as in the example of FIG. At the position, projection walls 33 and 35 having a height H are provided at positions where Z ₁ and Z ₂ are provided in the flow direction of the end wall surface on the platform 31 side.
[0020]
The dimensions Y ₁ , Y ₂ and Z ₁ , Z ₂ of the projection walls 33, 35 and the positions of the apexes 34, 36 are the same as the positional relationship described in FIG. 2, and the apexes 36, 34 are smooth curved surfaces. It is the formed top portion, and its locus is formed on a straight line orthogonal to the axial direction, and its position is made to coincide with the position of the throat 51.
[0021]
In the second embodiment of the above configuration, by providing a protruding wall having a height H on the end wall on the side of the chip shroud 32 and the platform 31, the fluid along the wall surface is locally along the smooth surface of the protruding wall. The speed of the boundary wall boundary layer fluid is increased, and the secondary flow generated near the shroud 32 and the platform 31 side end wall can be suppressed.
[0022]
The height H of the protrusion is set to such a height that the flow does not separate, and the position of the protrusion in the flow direction needs to be optimized in consideration of the balance with the throat position. In the second embodiment, the height H of the projection is projected with a limit of about 2.6% of the blade height S, and the top portions 34 and 36 of the projection are throated in the flow direction position as described above. The shape matches the part.
[0023]
【The invention's effect】
The end wall structure between the turbine blades of the present invention is as follows: (1) The inter-blade hub side wall surface of the turbine stationary blade has a protrusion shape having a top portion between the leading edge and the trailing edge, and the top portion of the protrusion shape is a curved surface. the shape and the trajectory of the vertex of the curved surface forms a straight line in a direction orthogonal to the turbine axis, further the position of the straight line is set to a position of the throat formed between the adjacent vanes, said projection-shaped The height of the blade is 2.6% or less of the blade height .
[0024]
With the above configuration, the flow of the fluid accelerates along the protrusion shape due to the protrusion shape of the hub side end surface between the stationary blades, thereby increasing the speed of the hub side end wall boundary layer fluid. Flow can be suppressed. Also, the height of the collision force shapes and 2.6% or less of the height of the blade, and measure the optimization is further match the position of the apex in the flow direction of the projection-shaped throat. This suppresses the occurrence of secondary flow on the hub side end wall surface between the stationary blades, and improves the efficiency by making the flow uniform at the stationary blade outlet.
[0025]
In (2) of the present invention, since the protrusion shape similar to that of the invention of (1) is provided on the inner wall surface of the shroud at the tip of the moving blade, the flow on the moving blade shroud wall surface is accelerated by this protrusion shape. speed of the wall boundary layer fluid is increased, Ru can be suppressed secondary flow generated near the shroud side wall surface.
[0026]
And further, in addition to the shroud inner end wall of the blade tip, in the rotor blade platforms outside end wall is formed with projection-shaped, flow shrouds and platforms across the wall are accelerated by this projection-shaped shroud And the secondary flow which generate | occur | produces in the platform both end wall vicinity can be suppressed. Also, the height of the collision force shapes and 2.6% or less of the height of the blade, and further matches the position of the vertex of the flow direction of the projection shape in the throat, and measure the optimization. As a result, the secondary flow is suppressed on the shroud at the tip of the moving blade and the both end walls of the platform, and the flow is uniform at the outlet of the moving blade, thereby improving the efficiency.
[Brief description of the drawings]
1A and 1B show an end wall structure between turbine blades according to a first embodiment of the present invention, in which FIG. 1A is a side view and FIG. 1B is a perspective view of an end wall portion;
FIG. 2 shows the positional relationship of the end wall structure between turbine blades according to the first embodiment, the second embodiment of the present invention, and a study example studied in connection with the present invention, and (a) is a plan view. (B) is sectional drawing of an end wall.
FIG. 3 is a side view of an end wall structure between turbine blades according to a study example studied in connection with the present invention.
FIG. 4 is a side view of an end wall structure between turbine blades according to a second embodiment of the present invention.
5A and 5B show a conventional end wall structure between turbine blades, where FIG. 5A is a sectional view of the blades, and FIG. 5B is a sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Stator blade 11 Hub side end wall 12 Casing 13, 23, 33, 35 Projection wall 14, 24, 34, 36 Top part 20, 30 Rotor blade 21, 31 Platform 22, 32 Tip shroud 51 Throat

Claims (2)

The inter-blade hub side wall surface of the turbine vane has a protruding shape with a apex between the leading and trailing blades, the apex of the protruding shape is a curved surface, and the locus of the apex of the curved surface is the turbine shaft A straight line is formed in a direction perpendicular to the vertical direction, and the position of the straight line is set to the position of the throat formed between adjacent stationary blades, and the height of the protrusion is 2.6% or less of the blade height. An end wall structure between turbine blades. The inner wall surface of the inner surface of the interblade shroud of the rotor blade, which has a shroud at the tip and the base is fixed to the platform on the hub side, has a protrusion shape having a top portion between the leading edge and the trailing edge of the blade. curved in shape, and the trajectory of the vertex of the curved surface to form a straight line in a direction orthogonal to the turbine axis, is set to further position the throat position of the straight line formed between the rotor blades adjacent Rutotomoni, wherein In addition to the projection shape of the shroud, the projection shape is also formed on the outer end wall surface of the platform, and the height of the projection shape is 2.6% or less of the blade height. of Tankabe構elephants.

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