A 715mm last-stage moving blade for a deep peak shaving steam turbine

Abstract

The present invention discloses a 715 mm last-stage moving blade for a deep peak shaving steam turbine. The blade profile structure of the moving blade is a variable-section twisted profile formed by superimposing a number of characteristic sections according to a rule. The superimposing rule of the characteristic sections is continuous and smooth transition from the root end to the top end along the blade height direction. The blade height H is 715 mm, and the relative value of the blade height H monotonically increases from 0.0 to 1.01. The absolute value of the installation angle c1 monotonically decreases from 73.7° to 19.9°. The characteristic parameters of each characteristic section are based on the root section. The relative value of the chord length b1 decreases monotonically from 1 to 0.77 from the root section to the top section. The relative value of the maximum thickness w1 decreases monotonically from 1 to 0.43 from the root section to the top section. The relative value of the axial width Xa decreases monotonically from 1 to 0.29 from the root section to the top section. The relative value of the cross-sectional area A decreases monotonically from 1 to 0.26 from the root section to the top section.

Description

Technical Field

[0001] The present invention relates to the field of steam turbine component manufacturing, and particularly to a 715 mm last-stage moving blade for a deep peak shaving steam turbine. Background Art

[0002] The capacity of domestic coal-fired power generation units is continuously increasing. Common large-capacity thermal power steam turbine peak shaving units have a power rating of 600 MW to 1000 MW. With the change of the total domestic electricity consumption, the requirements for the peak shaving and frequency modulation capabilities of large units are getting higher and higher. Therefore, improving the peak shaving and frequency modulation capabilities of the units and realizing the transformation of thermal power from baseload to load regulation type have become the primary concerns in the design and manufacture of the units.

[0003] As a key device in coal-fired power generation units, the efficiency of the steam turbine will directly affect the overall economic performance of the unit. Its applicability to power changes will determine the peak shaving ability of the unit. As the power rating of the unit increases, the capacity of the steam turbine increases, its initial parameters increase, the exhaust area of the low-pressure cylinder increases, the length of the last-stage blade increases, and the Mach number of blade use increases. The requirements for the aerodynamic performance and strength of the blade increase accordingly. Therefore, it is urgent to intensify the research and development of long blades suitable for peak shaving. Summary of the Invention

[0004] The purpose of the present invention is to provide, in view of the above problems, a 715 mm last-stage moving blade for a deep peak shaving steam turbine, which has excellent aerodynamic characteristics, can be applied to a large-capacity thermal power steam turbine peak shaving unit, and can improve the efficiency of the matching low-pressure cylinder.

[0005] The technical problems to be solved by the present invention are realized through the following technical solutions:

[0006] A 715mm last-stage moving blade for a deep peak shaving steam turbine. The blade body structure of the moving blade is a variable cross-section twisted profile formed by stacking a number of characteristic cross-sections according to a rule. The characteristic parameters of the moving blade include: the blade body height H; the contour lines of each of the characteristic cross-sections are closed curves formed by an inner arc curve and a back arc curve. The characteristic parameters of the characteristic cross-section include: the installation angle c1, the chord length b1, the maximum thickness w1, the axial width Xa, and the cross-sectional area A. The stacking rule of each of the characteristic cross-sections is continuous and smoothly transitions from the root end to the top end along the blade body height direction. The blade body height H is 715mm, and the relative value of the blade body height H monotonically increases from 0.0 to 1.01; the absolute value of the installation angle c1 monotonically decreases from 73.7° to 19.9°; based on the top cross-section, for the characteristic parameters of each of the characteristic cross-sections, the relative value of the chord length b1 monotonically decreases from the root cross-section to the top cross-section from 1 to 0.77; the relative value of the maximum thickness w1 monotonically decreases from the root cross-section to the top cross-section from 1 to 0.43; the relative value of the axial width Xa monotonically decreases from the root cross-section to the top cross-section from 1 to 0.29; the relative value of the cross-sectional area A monotonically decreases from the root cross-section to the top cross-section from 1 to 0.26.

[0007] The blade body structure is formed by seven characteristic cross-sections with different contour shapes continuously and smoothly transitioning from the root end to the top end along the blade body height direction.

[0008] The characteristic cross-section includes three key cross-sections, namely the A-A cross-section located at 0.0% of the blade body height H, the D-D cross-section located at 50.0% of the blade body height H, and the G-G cross-section located at 101% of the blade body height H; the theoretical contour lines of each key cross-section are described by the coordinates (X, Y) of a number of discrete points, and the discrete points are smoothly connected to obtain the theoretical contour line of the corresponding key cross-section.

[0009] 4. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 3, wherein the theoretical contour lines of each of the key cross-sections are described by the coordinates (X, Y) of 28 discrete points.

[0010] The theoretical contour line of the B-B cross-section is described by the following coordinates (X, Y) of discrete points:

[0011] (-128.907, -87.9715), (-131.628, -87.3723), (-132.872, -84.8799), (-132.351, -83.0612), (-114.336, -55.7232), (-94.2014, -29.9271), (-71.1677, -6.6839), (-45.3014, 13.34133), (-16.4967, 28.80803), (14.86169, 37.96561), (47.48617, 38.95926), (79.05016, 30.71582), (106.6638, 13.38475), (122.2815, -13.6982), (22.0418, -14.0404)(121.6038, -14.488), (121.087, -14.8417), (120.7084, -15.0183), (94.53649, -6.36196), (67.75611, 1.208781), (40.02019, 3.407964), (12.3656, 0.274964), (-14.3961, -7.4079), (-39.852, -18.7084), (-63.8661, -32.8273), (-86.4326, -49.1663)(-107.575, -67.3135), (-127.27, -87.0221).

[0012] The theoretical contour line of the D-D section is described by the coordinates (X, Y) of the following discrete points:

[0013] (-75.4691,-110.204),(-76.67,-110.199),(-77.4075,-109.251),(-77.3318,-108.439),(-67.7413,-86.2749),(-57.9502,-64.1986),(-48.1163,-42.1414),(-37.7912,-20.3116),(-25.9534,0.725653),(-11.2971,19.8805),(7.095102,35.42928),(29.15125,45.00345),(53.11314,46.43755),(73.11637,35.08723),(73.2777,33.85458),(73.01992,32.01228),(72.19072,30.34707),(71.36061,29.42166),(51.65678,22.914),(31.99657,15.89931),(14.0125,5.302315),(-2.05577,-8.04202),(-16.4833,-23.1567),(-29.6458,-39.3903),(-41.8594,-56.3517),(-53.3607,-73.8051),(-64.3226,-91.6027),(-74.8718,-109.648).

[0014] The theoretical contour line of the G-G section is described by the coordinates (X, Y) of the following discrete points:

[0015] (-38.9849,-117.9),(-40.0975,-118.043),(-40.8891,-117.248),(-40.9043,-116.486),(-34.8909,-96.2116),(-28.8293,-75.9515),(-22.8035,-55.6809),(-16.8537,-35.3878),(-10.9765,-15.0735),(-5.12489,5.24811),(0.792056,25.55079),(6.908412,45.79415),(14.66378,65.39243),(32.30689,75.16498),(32.40771,75.09042),(32.5435,74.96041),(32.65799,74.81131),(32.72116,74.70299),(26.89221,55.24284),(19.72302,36.03372),(12.59034,16.81101),(5.444972,-2.40699),(-1.74105,-21.6098),(-8.97978,-40.7928),(-16.2756,-59.9542),(-23.6294,-79.0934),(-31.04,-98.2107),(-38.5057,-117.307)。

[0016] The contour lines of each of the said characteristic cross-sections are allowed to have a tolerance zone, and the range of the tolerance zone is: within the contour shape range formed by taking the discrete points of the theoretical contour line of the corresponding characteristic cross-section as the centers and making envelope circles with a radius of 0.3 mm to 0.8 mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The blade body of the last-stage moving blade of the present invention has multiple characteristic cross-sections. By optimizing the contour line parameters of each characteristic cross-section, the blade body of the last-stage moving blade disclosed by the present invention has excellent aerodynamic performance; at the same time, the area change along the blade height direction is reasonable, the high-order smoothness of each characteristic cross-section of the blade body is excellent, and the subsonic and transonic flow characteristics are outstanding; the stacking of each cross-section along the blade height is continuous and smooth, and the area distribution is reasonable, so that the blade body of the last-stage moving blade disclosed by the present invention has the advantages of large strength margin and high reliability.

[0019] 2. The 715mm last-stage moving blade for the deep peak shaving steam turbine disclosed by the present invention can be applied to the peak shaving units of large-capacity thermal power steam turbines with a rotational speed of 3000 r / min and a power rating of 600 MW - 1000 MW. It provides the last-stage moving blade with excellent performance for the existing large-capacity thermal power units, improves the efficiency of the low-pressure cylinder, enhances the off-design performance, meets the requirements of market economy and power grid peak shaving, and increases the market competitiveness of China's power generation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the blade body of the present invention;

[0021] Figure 2 is Figure 1 a top view schematic diagram of

[0022] Figure 3 is Figure 1 、 Figure 2 a schematic diagram of the characteristic cross-section of the blade body structure in

[0023] Figure 4 a superimposed schematic diagram of all characteristic cross-sections;

[0024] Reference numerals in the drawings: Blade body height - H, installation angle - c1, chord length - b1, maximum thickness - w1, axial width - Xa, cross-sectional area - A. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0027] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that the meaning of "a plurality" is two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0029] As Figure 1 — Figure 4 Shown in the figure, a 715mm last-stage moving blade for a deep peak shaving steam turbine, the characteristic parameters of this moving blade are designed as follows: Based on the boundary conditions required by the project, it is determined that this set of blade profiles is applicable to the peak shaving units of large-capacity thermal power steam turbines with a rotational speed of 3000r / min and a power rating of 600MW to 1000MW. Its blade height is 715mm, and the optimal Mach number range is 0.8 to 1.5.

[0030] Specifically, the design contour line of the blade body of the moving blade is obtained by using three-dimensional modeling software to obtain 7 characteristic cross-sections, and the area change law of each cross-section is modified according to the strength design requirements to obtain the cross-sectional area distribution that meets the strength requirements. Then, a full three-dimensional computational fluid dynamics simulation software is used to perform aerodynamic analysis on the blade stage, and according to the flow characteristics of the stage, the local blade profile is adjusted, so as to obtain the characteristic cross-sections that meet the subsonic flow characteristics at the root and transonic flow characteristics at the top. Then, a full three-dimensional computational fluid dynamics simulation software is used to perform aerodynamic analysis on the blade stage. The blade body structure is optimized, smoothed and locally fine-tuned for each characteristic cross-section by using high-order b1ezier curves and third-order C-spline curves.

[0031] As Figure 1 、 Figure 2 Shown in the figure, the blade body is formed by stacking a plurality of characteristic cross-sections according to a rule to form a variable cross-section twisted profile. The specific characteristic parameters of the blade body are as follows: The blade height H, that is, the distance between the root cross-section and the top cross-section of the blade body, and the blade height H is equal to 715mm.

[0032] The contour line of each characteristic cross-section is a closed curve composed of an inner arc curve and a back arc curve, mainly including the chord length b1, the installation angle c1, the maximum thickness w1, the axial width Xa, and the cross-sectional area A. Among them, the installation angle c1, that is, the angle between the chord length and the circumferential (Y-direction); the chord length b1, that is, the distance between the inlet and outlet edges of the blade body cross-section; the maximum thickness w1, that is, the tangential width of the blade body cross-section; the cross-sectional area A, that is, the cross-sectional area of the blade body; the axial width Xa, that is, the axial width of the blade body cross-section.

[0033] The stacking rule of each of the characteristic cross-sections is a continuous and smooth transition along the blade height direction from the root to the top, and the relative value of the blade height H monotonically increases from 0.0 to 1.01; the absolute value of the installation angle c1 monotonically decreases from 73.7° to 19.9°. Taking the root cross-section as the reference, the relative value characteristics of the characteristic parameters of each of the characteristic cross-sections are as follows: 1) The chord length b1 monotonically decreases from 1.0 at the root cross-section to 0.77 at the top cross-section; 2) The maximum thickness w1 monotonically decreases from 1.0 at the root cross-section to 0.43 at the top cross-section; 3) The axial width Xa monotonically decreases from 1.0 at the root cross-section to 0.29 at the top cross-section; 4) The cross-sectional area A monotonically decreases from 1.0 at the root cross-section to 0.26 at the top cross-section.

[0034] The key cross-sections are determined in the following manner. As Figure 4 shown, the blade structure is formed by seven characteristic cross-sections with different contour shapes continuously and smoothly transitioning from the root end to the top end along the blade height H direction. Let the arrangement order of each characteristic cross-section from the root to the top be 1 to 7; as Figure 1 shown in Table 1, the blade structure uses the A-A cross-section at a relative height of 0.0%, the D-D cross-section at a relative height of 50%, and the G-G cross-section at a relative height of 101% as the key cross-sections. The theoretical contour lines of each key cross-section are described by the coordinates (X, Y) of a number of discrete points, and the discrete points are smoothly connected to form the theoretical contour line of the key cross-section. Each key cross-section is described by the coordinates (X, Y) of 20 to 90 discrete points; in this embodiment, the theoretical contour lines of each key cross-section are described by the coordinates (X, Y) of 28 discrete points.

[0035] Table 1 Relative heights of the three key cross-sections on the blade height H

[0036] Cross-section name Relative blade height A-A 0.0％ D-D 50％ G-G 101％

[0037] As shown in Table 2, the theoretical contour lines of the A-A cross-section, the D-D cross-section, and the G-G cross-section are described by the coordinates (X, Y) of the following discrete points respectively:

[0038] Table 2 Coordinate data of discrete points of the three key cross-sections

[0039]

[0040]

[0041] The actual dimensions of the contour lines of each of the characteristic cross-sections are allowed to have a tolerance band, and the range of the tolerance band is: within the contour shape range formed by the envelope circles with a radius of 0.3 mm to 0.8 mm centered on the discrete points of the theoretical contour line of the corresponding characteristic cross-section. The above is only the optimal solution, and it can also be within the range of the shape and size obtained by similarity modeling, rotation, or translation with the theoretical contour line as the reference.

[0042] Based on the blade profile structure provided in this embodiment, a 715 mm last-stage moving blade for a deep peak shaving steam turbine is designed. It not only has advanced aerodynamic characteristics but also can meet the strength requirements.

[0043] The above specific technical solutions are only used to illustrate the present invention, rather than to limit it; although the present invention has been described in detail with reference to the above specific technical solutions, those of ordinary skill in the art should understand that the present invention can still modify the above specific technical solutions, or perform equivalent replacements on some of the technical features, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the present invention.

Claims

1. A 715mm last-stage moving blade for a deep peak shaving steam turbine, the blade body structure of the moving blade is a variable-section twisted profile formed by stacking a number of characteristic cross-sections according to a rule, and the characteristic parameters of the moving blade include: Blade body height H; The contour line of each of the characteristic cross-sections is a closed curve formed by an inner arc curve and a back arc curve. The characteristic parameters of the characteristic cross-section include: installation angle c1, chord length b1, maximum thickness w1, axial width Xa, cross-sectional area A. The stacking rule of each of the characteristic cross-sections is continuous and smoothly transitional from the root end to the top end along the blade body height direction. It is characterized in that: The blade body height H is 715mm, and the relative value of the blade body height H monotonically increases from 0.0 to 1.01; The absolute value of the installation angle c1 monotonically decreases from 73.7° to 19.9°; Based on the root cross-section, for the characteristic parameters of each of the characteristic cross-sections, the relative value of the chord length b1 monotonically decreases from the root cross-section to the top cross-section from 1 to 0.77; The relative value of the maximum thickness w1 monotonically decreases from the root cross-section to the top cross-section from 1 to 0.43; The relative value of the axial width Xa monotonically decreases from the root cross-section to the top cross-section from 1 to 0.29; The relative value of the cross-sectional area A monotonically decreases from the root cross-section to the top cross-section from 1 to 0.

26.

2. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 1, characterized in that: The blade body structure is formed by seven characteristic cross-sections with different contour shapes continuously and smoothly transitioning from the root end to the top end along the blade body height direction.

3. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 1 or 2, characterized in that: The characteristic cross-section includes three key cross-sections. The key cross-sections include the A-A cross-section at 0.0% of the blade body height H, the D-D cross-section at 50.0% of the blade body height H, and the G-G cross-section at 101% of the blade body height H; the theoretical contour lines of each key cross-section are described by the coordinates (X, Y) of a number of discrete points, and the discrete points are smoothly connected to obtain the theoretical contour line of the corresponding key cross-section.

4. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 3, characterized in that, the theoretical contour lines of each of the key cross-sections are described by the coordinates (X, Y) of 28 discrete points.

5. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 3, characterized in that: The theoretical contour line of the A-A cross-section is described by the coordinates (X, Y) of the following discrete points: （-128.907，-87.9715），（-131.628，-87.3723），（-132.872，-84.8799），（-132.351，-83.0612），（-114.336，-55.7232），（-94.2014，-29.9271），（-71.1677，-6.6839），（-45.3014，13.34133），（-16.4967，28.80803），（14.86169，37.96561），（47.48617，38.95926），（79.05016，30.71582），（106.6638，13.38475），（122.2815，-13.6982），（22.0418，-14.0404）（121.6038，-14.488），（121.087，-14.8417），（120.7084，-15.0183），（94.53649，-6.36196），（67.75611，1.208781），（40.02019，3.407964），（12.3656，0.274964），（-14.3961，-7.4079），（-39.852，-18.7084），（-63.8661，-32.8273），（-86.4326，-49.1663）（-107.575，-67.3135），（-127.27，-87.0221）。 6. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 3, characterized in that: The theoretical contour line of the D-D cross-section is described by the coordinates (X, Y) of the following discrete points: (-75.4691, -110.204) , (-76.67, -110.199) ,（-77.4075, -109.251）,（-77.3318, -108.439）,（-67.7413, -86.2749）,（-57.9502, -64.1986）,（-48.1163, -42.1414）,（-37.7912, -20.3116）,（-25.9534, 0.725653）,（-11.2971, 19.8805）,（7.095102, 35.42928）,（29.15125, 45.00345）,（53.11314, 46.43755）,（73.11637,35.08723）,（73.2777, 33.85458）,（73.01992, 32.01228）,（72.19072, 30.34707）,（71.36061, 29.42166）,（51.65678, 22.914）,（31.99657, 15.89931）,（14.0125,5.302315）,（-2.05577, -8.04202）,（-16.4833, -23.1567）,（-29.6458, -39.3903）,（-41.8594, -56.3517）,( -53.3607, -73.8051) ,( -64.3226, -91.6027) ,( -74.8718,-109.648) 。 7. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 3, characterized in that: The theoretical contour line of the G-G cross-section is described by the coordinates (X, Y) of the following discrete points: （-38.9849, -117.9）,（-40.0975, -118.043）,（-40.8891, -117.248）,（-40.9043, -116.486）,（-34.8909, -96.2116）,（-28.8293, -75.9515）,（-22.8035, -55.6809）,（-16.8537, -35.3878）,（-10.9765, -15.0735）,（-5.12489, 5.24811）,（0.792056,25.55079）,（6.908412, 45.79415）,（14.66378, 65.39243）,（32.30689, 75.16498）,（32.40771, 75.09042）,（32.5435, 74.96041）,（32.65799, 74.81131）,（32.72116,74.70299）,（26.89221, 55.24284）,（19.72302, 36.03372）,（12.59034, 16.81101）,（5.444972, -2.40699）,（-1.74105, -21.6098）,（-8.97978, -40.7928）,（-16.2756, -59.9542）,（-23.6294, -79.0934）,（-31.04, -98.2107）,（-38.5057, -117.307）。 8. The 715mm last-stage moving blade for a deep peak shaving steam turbine according to claim 1 or 2, characterized in that: The contour lines of each of the characteristic cross-sections are permitted to have a tolerance zone, and the range of the tolerance zone is: within the contour shape range formed by taking the discrete points of the theoretical contour line of the corresponding characteristic cross-section as the centers and making envelope circles with a radius of 0.3 mm to 0.8 mm.

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