A wide-load blade profile for deep peak shaving of steam turbine units

Abstract

A wide-load blade profile for deep peak shaving of steam turbine units, which solves the problem of how to reduce the blade profile loss of peak shaving units and belongs to the field of steam turbine blade profiles. The present invention includes an inlet steam arc, a pressure surface curve, a suction surface curve, and an outlet steam arc; both ends of the pressure surface curve are respectively connected to and tangent to one end of the inlet steam arc and one end of the outlet steam arc, and both ends of the suction surface curve are respectively connected to and tangent to the other end of the inlet steam arc and the other end of the outlet steam arc; the pressure surface curve and the suction surface curve are generated by B-spline curves; and for the application to the last two-stage static blades and other-stage static blades, the last two-stage moving blades and other-stage moving blades of the low pressure, the ratio of the diameter φ1 of the outlet steam arc to the diameter φ2 of the inlet steam arc 1, the ratio of the maximum thickness D of the blade profile to the chord length b, the geometric inlet steam angle α, the ratio of the throat size o to the pitch t, and the installation angle are given. It can reduce the risk of flow separation during small volume flow operation during peak shaving, thereby effectively reducing the blade profile loss. max The ratio of the throat size o to the pitch t, and the installation angle. It can reduce the risk of flow separation during small volume flow operation during peak shaving, thereby effectively reducing the blade profile loss.

Description

Technical Field

[0001] The present invention belongs to the field of steam turbine blade profiles, and discloses a wide-load blade profile dedicated to deep peak shaving of steam turbine units, which is particularly applicable to peak shaving units above 300 MW. Background Art

[0002] When a steam turbine is used for peak shaving, it operates at a low load for a long time, deviating greatly from the design point, which causes early separation of the boundary layer near the blade wall surface, serious backflow, large vortex size, and deterioration of aerodynamic performance. Up to now, there is no blade profile dedicated to the blades of peak shaving units in the field of steam turbine blade profiles. In order to ensure the economy of the blades under the low-load peak shaving condition, it is necessary to develop a blade profile dedicated to the blades of peak shaving units. Summary of the Invention

[0003] Aiming at the problem of how to reduce the profile loss of the blades of peak shaving units, the present invention provides a wide-load blade profile for deep peak shaving of steam turbine units.

[0004] A wide-load blade profile for deep peak shaving of steam turbine units provided by the present invention is applied to the last two-stage static blades of the low pressure stage, and includes an inlet arc 1, a pressure surface curve 2, a suction surface curve 3, and an outlet arc 4;

[0005] Both ends of the pressure surface curve 2 are connected and tangent to one end of the inlet arc 1 and one end of the outlet arc 4 respectively, and both ends of the suction surface curve 3 are connected and tangent to the other end of the inlet arc 1 and the other end of the outlet arc 4 respectively;

[0006] The pressure surface curve 2 and the suction surface curve 3 are generated by B-spline curves;

[0007] The ratio of the diameter φ1 of the outlet arc 4 to the diameter φ2 of the inlet arc 1 is μ, the maximum thickness D of the blade profile max The ratio to the chord length b is κ, the geometric inlet angle is α, the ratio of the throat size o to the pitch t is λ, and the installation angle is α y ;

[0008] 0.023 ≤ μ ≤ 0.056, 0.172 ≤ κ ≤ 0.291, 50.31° ≤ α ≤ 75.16°, 0.26 ≤ λ ≤ 0.44, 40.74° ≤ α y ≤ 62.30°.

[0009] The present invention also provides a wide-load blade profile for deep peak shaving of steam turbine units, which is applied to the static blades of other stages except the last two-stage static blades of the low pressure stage, and includes an inlet arc 1, a pressure surface curve 2, a suction surface curve 3, and an outlet arc 4;

[0010] Both ends of the pressure surface curve 2 are connected and tangent to one end of the steam inlet arc 1 and one end of the steam outlet arc 4 respectively, and both ends of the suction surface curve 3 are connected and tangent to the other end of the steam inlet arc 1 and the other end of the steam outlet arc 4 respectively;

[0011] The pressure surface curve 2 and the suction surface curve 3 are generated by B-spline curves;

[0012] The ratio of the diameter φ1 of the steam outlet arc 4 to the diameter φ2 of the steam inlet arc 1 is μ, and the ratio of the maximum thickness D of the blade profile to the chord length b is κ. The geometric steam inlet angle is α, and the ratio of the throat size o to the pitch t is λ. max The installation angle is α; y ;

[0013] 0.134 ≤ μ ≤ 0.161, κ = 0.324, 70.27° ≤ α ≤ 96.27°, 0.26 ≤ λ ≤ 0.44, 40.74° ≤ α y ≤ 62.30°.

[0014] The present invention also provides a wide-load blade profile for deep peak shaving of steam turbine units, which is applied to the last two-stage moving blades of the low pressure stage and includes a steam inlet arc 1, a pressure surface curve 2, a suction surface curve 3 and a steam outlet arc 4;

[0015] Both ends of the pressure surface curve 2 are connected and tangent to one end of the steam inlet arc 1 and one end of the steam outlet arc 4 respectively, and both ends of the suction surface curve 3 are connected and tangent to the other end of the steam inlet arc 1 and the other end of the steam outlet arc 4 respectively;

[0016] The pressure surface curve 2 and the suction surface curve 3 are generated by B-spline curves;

[0017] The ratio of the diameter φ1 of the steam outlet arc 4 to the diameter φ2 of the steam inlet arc 1 is μ, and the ratio of the maximum thickness D of the blade profile to the chord length b is κ. The geometric steam inlet angle is α. The ratio of the throat size o to the pitch t is λ; max ;

[0018] 0.196 ≤ μ ≤ 0.536, 0.048 ≤ κ ≤ 0.180, 37.34° ≤ α ≤ 133.33°, 0.26 ≤ λ ≤ 0.44.

[0019] The present invention also provides a wide-load blade profile for deep peak shaving of steam turbine units, which is applied to the moving blades of other stages except the last two-stage moving blades of the low pressure stage and includes a steam inlet arc 1, a pressure surface curve 2, a suction surface curve 3 and a steam outlet arc 4;

[0020] Both ends of the pressure surface curve 2 are connected and tangent to one end of the steam inlet arc 1 and one end of the steam outlet arc 4 respectively, and both ends of the suction surface curve 3 are connected and tangent to the other end of the steam inlet arc 1 and the other end of the steam outlet arc 4 respectively;

[0021] The pressure surface curve 2 and the suction surface curve 3 are generated by B-spline curves;

[0022] The ratio of the diameter φ1 of the steam outlet circular arc 4 to the diameter φ2 of the steam inlet circular arc 1 is μ, and the ratio of the maximum thickness D of the blade profile to the chord length b is κ. The geometric steam inlet angle is α, and the ratio of the throat size o to the pitch t is λ; max 0.062 ≤ μ ≤ 0.173, κ = 0.275, 87.05° ≤ α ≤ 133.62°, 0.26 ≤ λ ≤ 0.44.

[0023] 0.062 ≤ μ ≤ 0.173, κ = 0.275, 87.05° ≤ α ≤ 133.62°, 0.26 ≤ λ ≤ 0.44.

[0024] Advantages of the present invention: The blade profile of the present invention solves the problem that there is no dedicated blade profile for peak shaving units at present. It has a relatively high efficiency value under low load conditions, which is suitable for the characteristics of long-term low load operation of steam turbine peak shaving units; applying the blades of the present invention can reduce the risk of flow separation in small volume flow during peak shaving, delay the growth and development of separation bubbles, thereby effectively reducing the profile loss, and the blades have a relatively high efficiency under low load conditions; applying the blade profile of the present invention and combining the methods of tilting and twisting to complete the three-dimensional blade forming can enable the blades to obtain a reaction degree distribution superior to that of traditional blade profiles during peak shaving operation and improve the gas flow in the cascade channel. Description of the Drawings

[0025] Figure 1 is a schematic diagram of the blade profile disclosed in this patent;

[0026] Figure 2 is a schematic diagram of the geometric parameters of the blade profile;

[0027] Figure 3 is Figure 2 an enlarged view of I in;

[0028] Figure 4 is a schematic diagram of the throat size o and the pitch t;

[0029] Figure 5 is a schematic diagram of the working part of the low-pressure last-stage stationary blade;

[0030] Figure 6 is a schematic diagram of the working part of the low-pressure last-stage moving blade;

[0031] Figure 7 is a graph showing the trend of the efficiency of the last-stage blade changing with the load;

[0032] Figure 8 is a schematic diagram showing the radial distribution of the reaction degree of the low-pressure last-stage blade under different load conditions. Detailed Embodiments

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0034] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but it is not limited to the present invention.

[0036] The wide-load blade profile for deep peak shaving of steam turbine units in this embodiment will be described in combination with Figure 1 to - Figure 4 to illustrate this embodiment. The profile line consists of 4 parts: the inlet arc 1, the pressure surface curve 2, the suction surface curve 3, and the outlet arc 4. The ratio μ of the diameter of the outlet arc 4 to the diameter of the inlet arc 1 has the following characteristics. When applied to the last two-stage static blades of the low-pressure stage, 0.023 ≤ μ ≤ 0.056; when applied to the static blades of other stages, 0.134 ≤ μ ≤ 0.161; when applied to the last two-stage moving blades of the low-pressure stage, 0.196 ≤ μ ≤ 0.536; when applied to the moving blades of other stages, 0.062 ≤ μ ≤ 0.173. The pressure surface curve 2 and the suction surface curve 3 are generated by B-spline curves. The pressure surface curve 2 is tangent to the edge points of the inlet arc 1 and the outlet arc 4, and the suction surface curve 3 is tangent to the edge points of the inlet arc 1 and the outlet arc 4. The ratio λ of the throat size o to the pitch t has the following characteristics, 0.26 ≤ λ ≤ 0.44. The ratio κ of the maximum thickness Dmax of the blade profile to the chord length b has the following characteristics. When applied to the last two-stage static blades of the low-pressure stage, 0.172 ≤ κ ≤ 0.291; when applied to the static blades of other stages, κ = 0.324; when applied to the last two-stage moving blades of the low-pressure stage, 0.048 ≤ κ ≤ 0.180; when applied to the moving blades of other stages, κ = 0.275. The installation angle α of the blade profile for the static blade y has the following characteristics, 40.74° ≤ α y ≤ 62.30°. The geometric inlet angle α of the blade profile has the following characteristics. When applied to the last two-stage static blades of the low-pressure stage, 50.31° ≤ α ≤ 75.16°; when applied to the static blades of other stages, 70.27° ≤ α ≤ 96.27°; when applied to the last two-stage moving blades of the low-pressure stage, 37.34° ≤ α ≤ 133.33°; when applied to the moving blades of other stages, 87.05° ≤ α ≤ 133.62°.

[0037] Example 1. This embodiment applies the blade profile to the low-pressure last-stage blades of a peaking steam turbine unit. The wide-load blade profile of this embodiment is stacked according to the following method. Along the radial position of the stator blade from 0% to 100%, the diameter of the exit arc 4 and the diameter of the inlet arc 1 The ratio μ increases from 0.026 to 0.053. The ratio κ of the maximum thickness D max of the blade profile to the chord length b increases from 0.176 to 0.288. The geometric inlet angle α of the blade profile increases from 51.53° to 74.39°. The blade profile adopts an inclined and twisted manner along the blade height and is smoothly transitioned to generate the stator blade.

[0038] Example 2. The wide-load blade profile of this embodiment is stacked according to the following method. Along the radial position of the rotor blade from 0% to 100%, the diameter of the exit arc 4 and the diameter of the inlet arc 1 The ratio μ decreases from 0.504 at the 0% position to 0.205 at the 50% position and then increases to 0.521 at the 100% position; the ratio κ of the maximum thickness D max of the blade profile to the chord length b decreases from 0.167 to 0.049. The geometric inlet angle α of the blade profile increases from 40.29° to 161.53°. The blade profile adopts an inclined and twisted manner along the blade height and is smoothly transitioned to generate the rotor blade.

[0039] The full three-dimensional CFD simulation is used to calculate and compare the aerodynamic performance of the last stage at different loads. When operating at the 50% load and a back pressure of 3.21 kPa, the efficiency of the last-stage blade is 2.5% higher than that at the 100% load and a back pressure of 4.65 kPa; when operating at the 25% load and a back pressure of 2.63 kPa, the scale of the recirculation vortex is only about 17% of the outlet height. The reaction degree at the root of the low-pressure last-stage blade is above 0.15 within a relatively wide load range. At about 47% load condition, the reaction degree at the root starts to be lower than 0.15, and at the 25% load condition, the reaction degree at the root starts to be negative.

[0040] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not depart from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A wide-load blade profile for deep peak shaving of steam turbine units, characterized in that, Applied to the last two-stage stationary blades of low pressure, the blade profile includes an inlet steam arc (1), a pressure surface curve (2), a suction surface curve (3), and an outlet steam arc (4); The two ends of the pressure surface curve (2) are respectively connected and tangent to one end of the inlet steam arc (1) and one end of the outlet steam arc (4), and the two ends of the suction surface curve (3) are respectively connected and tangent to the other end of the inlet steam arc (1) and the other end of the outlet steam arc (4); The pressure surface curve (2) and the suction surface curve (3) are generated by B-spline curves; The ratio of the diameter φ1 of the steam outlet arc (4) to the diameter φ2 of the steam inlet arc (1) is μ, and the ratio of the maximum thickness D of the blade profile to the chord length b is κ. The geometric steam inlet angle is α, the ratio of the throat size o to the pitch t is λ, and the installation angle is α max ; y ; 0.023 ≤ μ ≤ 0.056, 0.172 ≤ κ ≤ 0.291, 50.31° ≤ α ≤ 75.16°, 0.26 ≤ λ ≤ 0.44, 40.74° ≤ α y ≤ 62.30°.

2. A wide-load blade profile for deep peak shaving of steam turbine units, characterized in that Applied to the stationary blades of other stages except the last two-stage stationary blades of low pressure, the blade profile includes an inlet steam arc (1), a pressure surface curve (2), a suction surface curve (3), and an outlet steam arc (4); The two ends of the pressure surface curve (2) are respectively connected and tangent to one end of the inlet steam arc (1) and one end of the outlet steam arc (4), and the two ends of the suction surface curve (3) are respectively connected and tangent to the other end of the inlet steam arc (1) and the other end of the outlet steam arc (4); The pressure surface curve (2) and the suction surface curve (3) are generated by B-spline curves; The ratio of the diameter φ1 of the steam outlet arc (4) to the diameter φ2 of the steam inlet arc (1) is μ, and the ratio of the maximum blade thickness D max to the chord length b is κ, the geometric steam inlet angle is α, the ratio of the throat size o to the pitch t is λ, and the installation angle is α y ; 0.134 ≤ μ ≤ 0.161, κ = 0.324, 70.27° ≤ α ≤ 96.27°, 0.26 ≤ λ ≤ 0.44, 40.74° ≤ α y ≤ 62.30°.

3. A wide-load blade profile for deep peak shaving of steam turbine units, characterized in that, Applied to the last two-stage moving blades of low pressure, the blade profile includes an inlet steam arc (1), a pressure surface curve (2), a suction surface curve (3), and an outlet steam arc (4); The two ends of the pressure surface curve (2) are respectively connected and tangent to one end of the inlet steam arc (1) and one end of the outlet steam arc (4), and the two ends of the suction surface curve (3) are respectively connected and tangent to the other end of the inlet steam arc (1) and the other end of the outlet steam arc (4); The pressure surface curve (2) and the suction surface curve (3) are generated by B-spline curves; The ratio of the diameter φ1 of the steam outlet arc (4) to the diameter φ2 of the steam inlet arc (1) is μ, and the ratio of the maximum blade thickness D max to the chord length b is k, the geometric steam inlet angle is α, and the ratio of the throat size o to the pitch t is λ; 0.196 ≤ μ ≤ 0.536, 0.048 ≤ κ ≤ 0.180, 37.34° ≤ α ≤ 133.33°, 0.26 ≤ λ ≤ 0.

44.

4. A wide-load blade profile for deep peak shaving of steam turbine units, characterized in that, Applied to the moving blades of other stages except the last two-stage moving blades of low pressure, the blade profile includes an inlet steam arc (1), a pressure surface curve (2), a suction surface curve (3), and an outlet steam arc (4); The two ends of the pressure surface curve (2) are respectively connected and tangent to one end of the inlet steam arc (1) and one end of the outlet steam arc (4), and the two ends of the suction surface curve (3) are respectively connected and tangent to the other end of the inlet steam arc (1) and the other end of the outlet steam arc (4); The pressure surface curve (2) and the suction surface curve (3) are generated by B-spline curves; The ratio of the diameter φ1 of the steam outlet arc (4) to the diameter φ2 of the steam inlet arc (1) is μ, and the ratio of the maximum thickness D of the blade profile max to the chord length b is κ, the geometric steam inlet angle is α, and the ratio of the throat size o to the pitch t is λ; 0.062 ≤ μ ≤ 0.173, κ = 0.275, 87.05° ≤ α ≤ 133.62°, 0.26 ≤ λ ≤ 0.

44.

5. The wide-load blade profile for deep peak shaving of steam turbine units according to any one of claims 1, 2, 3 or 4, characterized in that The blade profile is inclined and twisted along the blade height.

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