Turbine blade adopting transverse and longitudinal pipeline cooling structure

Abstract

The invention belongs to the technical field of turbine blade cooling, and discloses a turbine blade adopting a transverse and longitudinal pipeline cooling structure, which comprises a front edge air film hole formed in the front edge of the blade, a tail edge crack formed in the tail edge of the blade, and a first cavity, a second cavity, a third cavity and a fourth cavity which are sequentially formed in the blade along the chord length direction of a blade body, the first chamber is close to the front edge gas film hole, and the fourth chamber is close to the tail edge crack; a plurality of transverse cooling pipelines and vertical cooling pipelines are further arranged in the blades; the two ends of the transverse cooling pipeline are connected with the corresponding cavities respectively and are arranged perpendicular to the height direction of the blade, and the vertical cooling pipeline is arranged in the height direction of the blade and penetrates through the blade. Air film holes in the pressure side and the suction side of a traditional blade are omitted, the transverse cooling pipeline and the vertical cooling pipeline are designed in the blade, the flowing path of cooling gas is optimized, the contact area between the cooling gas and the interior of the blade is increased, and therefore the more efficient cooling effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of turbine blade cooling, and in particular to a turbine blade adopting a horizontal and vertical pipeline cooling structure. Background Art

[0002] Common turbine blade cooling methods include film cooling, impingement cooling, and convection cooling. The turbine blade structure can be divided into three parts according to the position: the leading edge, the mid-chord, and the trailing edge. The leading edge area usually adopts a combination of impingement cooling and film cooling to cope with the direct impact of high-temperature combustion gas; the mid-chord area strengthens heat exchange by setting spoiler ribs, depressions and other structures in the inner cooling channel; the trailing edge area mostly adopts column rib spoiler cooling to enhance the heat exchange effect in the channel.

[0003] In the design of traditional turbine blades, a large number of film holes are arranged on the pressure side and the suction side. The cold air in the cooling channel inside the blade flows out through these discrete film holes. Under the action of the high-temperature mainstream gas, a layer of cold air film close to the wall is formed on the surface of the blade, isolating the high-temperature gas to reduce the surface temperature of the blade. Although this film cooling method can protect the blade to a certain extent, it also has the following problems: 1. The surface temperature distribution is uneven. The discrete distribution of the film holes leads to uneven coverage of the cooling gas on the blade surface, which is easy to form local high-temperature areas and increase the risk of thermal stress concentration; 2. The cooling efficiency is limited. The film cooling depends on the coverage effect of the cooling gas on the blade surface, but under high temperature and high pressure environment, the film is easily destroyed by the mainstream gas, resulting in a decrease in cooling effect; 3. When the mainstream gas temperature decreases, the cooling gas flowing out of the film cooling will gradually reduce the temperature of the mainstream gas, making the mainstream temperature of the subsequent stages of blades insufficient, thereby affecting the overall performance of the gas turbine; 4. The processing is complex and clogged. The processing accuracy of the film holes is high, which increases the manufacturing cost. At the same time, the film holes are easily clogged by pollutants in long-term use, affecting the cooling effect and reliability. Summary of the invention

[0004] In order to solve the problems of uneven surface temperature distribution, easy to cause thermal stress concentration, limited cooling efficiency, reduced mainstream gas temperature and complex processing in the air film cooling method used in the above-mentioned prior art traditional turbine blades, the present invention proposes a turbine blade with a horizontal and vertical pipeline cooling structure, aiming to solve the problems of complex processing, easy clogging and aerodynamic loss of traditional air film holes, while improving cooling efficiency and reliability.

[0005] The present invention is achieved through the following technical scheme: it includes a leading edge air film hole arranged at the leading edge of the blade and a trailing edge slit arranged at the trailing edge of the blade, and also includes a first chamber, a second chamber, a third chamber and a fourth chamber arranged in sequence inside the blade along the chord length direction of the blade body, the first chamber is close to the leading edge air film hole, and the fourth chamber is close to the trailing edge slit; a plurality of transverse cooling pipelines and vertical cooling pipelines are also arranged inside the blade; the two ends of the transverse cooling pipeline are respectively connected to the corresponding chambers and are arranged perpendicular to the height direction of the blade, and the vertical cooling pipeline is arranged along the height direction of the blade and runs through the blade.

[0006] As a further preference, the transverse cooling pipelines include two types, one connecting the first chamber and the third chamber, and the other connecting the second chamber and the fourth chamber.

[0007] As a further preference, the two types of transverse cooling pipelines are staggered and distributed at equal intervals on the pressure side and the suction side of the blade.

[0008] As a further preference, the number of the transverse cooling pipes on the pressure side and the suction side of the blade is 26, and the number of the two types of transverse cooling pipes is the same.

[0009] As a further preference, the cross-section of the transverse cooling pipeline is circular.

[0010] As a further preference, the ratio of the tube diameter of the transverse cooling pipe to the wall thickness of the pressure side of the blade is 1.4:3.6, and the ratio of the tube diameter of the transverse cooling pipe to the wall thickness of the suction side of the blade is 1.4:2.6.

[0011] As a further preference, the vertical cooling pipelines are distributed at equal intervals along the profile direction of the pressure side and the suction side of the blade.

[0012] As a further preference, the cross-section of the vertical cooling pipeline is circular.

[0013] As a further preference, the number of the vertical cooling pipelines on the pressure side and the suction side of the blade is 23.

[0014] As a further preference, the ratio of the diameter of the vertical cooling pipeline to the wall thickness of the pressure side of the blade is 0.5:3.6, and the ratio of the diameter of the vertical cooling pipeline to the wall thickness of the suction side of the blade is 0.5:2.6.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention designs a turbine blade that adopts a horizontal and vertical pipeline cooling structure inside the blade wall, optimizes the flow path of the cooling gas, increases the contact area between the cooling gas and the inside of the blade, prolongs the time that the cooling gas stays inside the turbine blade, improves the heat exchange effect of the cooling channel inside the turbine blade, achieves a more efficient cooling effect, makes the blade surface temperature more uniform, and improves the overall performance of the gas turbine to a certain extent.

[0017] 2. The present invention proposes a novel turbine blade cooling structure, which achieves a more efficient cooling effect by deleting the air film holes on the pressure side and suction side of the traditional blade and designing transverse and vertical cooling pipes inside the blade to optimize the flow path of the cooling gas and increase the contact area between the cooling gas and the inside of the blade.

[0018] 3. The present invention uses cooling gas to cool the turbine blades through horizontal and vertical cooling pipes. Compared with traditional turbine blades, the horizontal and vertical cooling channels are distributed on the pressure side and suction side of the turbine blades. The cold air flows through the horizontal and vertical cooling channels on both sides, reducing the temperature of the pressure surface and suction surface of the turbine blades. The cold air flowing out from the leading edge and the trailing edge flows downstream along the blade surface under the action of the mainstream, further reducing the average temperature of the blade surface and improving the tolerance of the turbine blades in high temperature environments. At the same time, the horizontal and vertical cooling channels distributed in a "well" shape optimize the flow path of the cooling gas, increase the contact area between the cooling gas and the inside of the blade and the heat exchange time of the cold air, and make the temperature distribution on both sides of the blade more uniform to a large extent.

[0019] 4. The present invention removes the air film holes on the suction and pressure surfaces of the turbine blades, so that the mainstream gas temperature in the channel remains high, which improves the overall efficiency of the gas turbine to a certain extent. In addition, the processing accuracy of the air film holes is high, which increases the manufacturing cost. At the same time, the air film holes are easily blocked by pollutants during long-term use, affecting the cooling effect and reliability. The present invention removes the air film holes, simplifies the blade structure, reduces the processing difficulty and manufacturing cost, and avoids the problem of air film hole blockage, thereby improving the long-term reliability of the blade.

[0020] 5. The structure designed in the present invention reduces the interference with the mainstream gas temperature while ensuring the cooling effect of the blades, thereby improving the overall performance of the gas turbine and ensuring the safe and reliable operation of the gas turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top view of the overall structure of the present invention.

[0022] Figure 2 It is a front perspective view of the overall structure of the present invention.

[0023] Figure 3 This is the temperature cloud diagram of the traditional blade.

[0024] Figure 4 This is a temperature cloud diagram of the turbine blades adopting the horizontal and vertical pipeline cooling structure of the present invention.

[0025] Indicated in the figure:

[0026] 1. Leading edge air film hole; 2. First chamber; 3. Second chamber; 4. Third chamber; 5. Fourth chamber; 6. Horizontal cooling pipeline; 7. Vertical cooling pipeline; 8. Trailing edge split. DETAILED DESCRIPTION

[0027] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings.

[0028] like Figure 1 and Figure 2 As shown, the present invention provides a turbine blade adopting a horizontal and vertical pipeline cooling structure, including a turbine blade, a horizontal cooling pipeline 6 and a vertical cooling pipeline 7. There are several internal cooling channels inside the turbine blade, that is, several horizontal cooling pipelines 6 and vertical cooling pipelines 7. The inside of the turbine blade is divided into four chambers along the chord length direction, namely the first chamber 2, the second chamber 3, the third chamber 4 and the fourth chamber 5. The horizontal cooling pipelines 6 are respectively arranged on the pressure side and the suction side of the turbine blade, and are evenly spaced along the blade height direction. The pressure side of the turbine blade is the side with higher static pressure on the blade, usually located on the curved surface of the blade facing the incoming flow direction of the fluid. According to the Bernoulli principle, the lower the flow rate, the higher the static pressure, so the fluid flow rate is slower on the pressure side of the turbine blade, and the shape is usually more gentle or convex; in contrast, the suction side of the turbine blade is the side with lower static pressure on the blade, usually located on the curved surface of the blade facing the incoming flow direction, and the fluid flow rate is faster on this side, and the shape is usually more curved or concave. The horizontal cooling pipelines 6 are connected to the corresponding chambers respectively. The vertical cooling pipes 7 extend along the blade height direction and are evenly spaced along the profile direction on both sides of the blade, so that the range of the transverse cooling pipes 6 and the vertical cooling pipes 7 is as large as possible, allowing the transverse cooling pipes 6 and the vertical cooling pipes 7 to better cover the turbine blades, making the cooling effect of the cold air on the turbine blades more obvious and reducing the average temperature of the blade surface.

[0029] The turbine blade designed by the present invention deletes the air film holes on the suction side and pressure side of the blade, retains the leading edge air film holes 1 and the trailing edge slits 8, and adopts a horizontal and vertical staggered cooling pipeline design inside the blade wall, so that the cooling gas can fully flow in the transverse cooling pipeline 6 and the vertical cooling pipeline 7, increase the contact area between the cooling gas and the inside of the blade, and significantly improve the cooling efficiency. The transverse cooling pipeline 6 connects the first chamber 2 and the third chamber 4, as well as the second chamber 3 and the fourth chamber 5, respectively, and is located on the suction side and the pressure side of the blade, and is evenly spaced along the blade height direction. There are 13 transverse cooling pipelines 6 distributed on the pressure side and 13 transverse cooling pipelines 6 distributed on the suction side. This arrangement can form a good cold air passage inside the blade, and the cold air passages have little mutual influence. The cross-section of the transverse cooling pipeline 6 is preferably circular, and the pipe diameter is 1.4mm. The vertical cooling pipeline 7 extends along the blade height direction and runs through the turbine blade. The vertical cooling pipes 7 are evenly spaced along the profile direction of the suction side and the pressure side of the blade, and 23 vertical cooling pipes 7 are distributed on the suction side and the pressure side respectively. The cross-section of the vertical cooling pipe 7 is preferably circular, and the pipe diameter is 0.5 mm. In this way, the range of the transverse cooling pipe 6 and the vertical cooling pipe 7 can be as large as possible, so that the cooling effect of the cold air on the turbine blades is more obvious. The leading edge film hole 1 is arranged on the side close to the first chamber 2, and the trailing edge slit 8 is arranged on the side close to the fourth chamber 5; and the width of the side where the leading edge film hole 1 is arranged is greater than the width of the side where the trailing edge slit 8 is arranged.

[0030] The transverse cooling pipelines 6 are divided into two types, one connecting the first chamber 2 and the third chamber 4, with 13 transverse cooling pipelines 6 distributed on the pressure side of the blade, and 13 transverse cooling pipelines 6 distributed on the suction side of the blade; the other transverse cooling pipeline 6 connects the second chamber 3 and the fourth chamber 5, with 13 transverse cooling pipelines 6 distributed on the pressure side of the blade, and 13 transverse cooling pipelines 6 distributed on the suction side of the blade. There are a total of 26 transverse cooling pipelines 6 on the pressure side of the turbine blade, and a total of 26 transverse cooling pipelines 6 on the suction side. The two types of transverse cooling pipelines 6 are staggered and parallel to each other on the pressure side and suction side of the blade. Since the transverse cooling pipelines 6 are evenly spaced in the blade height direction on the pressure side and suction side of the blade, and the inlet cold air flow rate remains constant, it is not the case that the more transverse cooling pipelines 6 there are, the better the cooling effect of the turbine blade. When the number of transverse cooling pipes 6 increases, the average cold air flow rate to each transverse cooling pipe 6 will decrease. Although the spacing between the transverse cooling pipes 6 is relatively small at this time, the cold air flow rate allocated to each transverse cooling pipe 6 is relatively small, which will cause the overall cooling effect of the transverse cooling pipe 6 to deteriorate; when the number of transverse cooling pipes 6 decreases, the average cold air flow rate to each transverse cooling pipe 6 will increase, but at this time the spacing between the transverse cooling pipes 6 is relatively large. Although the cold air flow rate allocated to each transverse cooling pipe 6 is relatively large, the influence range of each transverse cooling pipe 6 is relatively small, which will cause the overall cooling effect of the transverse cooling pipe 6 to deteriorate and affect the uniformity of temperature distribution on the blade surface. Similarly, the size of the pipe diameter also has an effect. Too large or too small a pipe diameter will cause the cooling effect of the blade to deteriorate. Therefore, it is necessary to select the appropriate number and diameter of the transverse cooling pipes 6 to ensure that the overall cooling effect of the transverse cooling pipes 6 is the best. The present invention distributes 26 transverse cooling pipes 6 on the pressure side and suction side of the turbine blade, and the pipe diameter is set to 1.4mm. The suction side wall thickness is 3.6mm, and the ratio of the diameter of the transverse cooling pipe 6 to the suction side wall thickness of the turbine blade is 1.4:3.6; the pressure side wall thickness is 2.6mm, and the ratio of the diameter of the transverse cooling pipe 6 to the pressure side wall thickness of the turbine blade is 1.4:2.6. For the transverse cooling pipe 6 connecting the first chamber 2 and the third chamber 4, the cooling gas enters through the cold air inlet of the third chamber 4, passes through the transverse cooling pipe 6, flows into the first chamber 2, and is ejected from the leading edge air film hole 1. The cold air flows through the transverse cooling pipe 6 to cool the blade surface; for the transverse cooling channel 6 connecting the second chamber 3 and the fourth chamber 5, the cooling gas enters through the cold air inlet of the second chamber 3, passes through the transverse cooling pipe 6, flows into the fourth chamber 5, and is ejected from the trailing edge slit 8 under the action of the trailing edge column rib turbulence. The cold air flows through the transverse cooling channel 6 to cool the blade surface.

[0031] The vertical cooling pipeline 7 extends along the blade height direction and penetrates the turbine blade. The vertical cooling pipeline 7 is evenly spaced along the profile direction of the pressure side and suction side of the blade, with 23 vertical cooling pipelines 7 distributed on the pressure side and 23 vertical cooling pipelines 7 distributed on the suction side. Since the vertical channels are evenly spaced along the profile direction of the pressure side and suction side of the blade, and the inlet cold air flow rate remains constant, the more vertical cooling pipelines 7 there are, the better the cooling effect of the turbine blade is not necessarily. When the number of vertical cooling pipes 7 increases, the average cold air flow to each vertical cooling pipe 7 will decrease. Although the spacing between the vertical cooling pipes 7 is relatively small at this time, the cold air flow allocated to each vertical cooling pipe 7 is relatively small, which will cause the overall cooling effect of the vertical cooling pipes 7 to deteriorate; when the number of vertical cooling pipes 7 decreases, the average cold air flow to each vertical cooling pipe 7 will increase, but at this time the spacing between the vertical cooling pipes 7 is relatively large. Although the cold air flow allocated to each vertical cooling pipe 7 is relatively large, the influence range of each vertical cooling pipe 7 is relatively small, which will cause the overall cooling effect of the vertical cooling pipes 7 to deteriorate and affect the temperature distribution uniformity on the blade surface. Similarly, the size of the pipe diameter also has an effect. Too large or too small a pipe diameter will cause the cooling effect of the blade to deteriorate. Therefore, it is necessary to select the appropriate number and diameter of the vertical cooling pipes 7 to ensure the best overall cooling effect of the vertical cooling pipes 7. The present invention selects to distribute 23 vertical cooling pipes 7 on the pressure side and suction side of the turbine blade, and the pipe diameter is set to 0.5mm. The suction side wall thickness is 3.6mm, and the ratio of the vertical cooling pipe 7 diameter to the suction side wall thickness of the turbine blade is 0.5:3.6; the pressure side wall thickness is 2.6mm, and the ratio of the vertical cooling pipe 7 diameter to the pressure side wall thickness of the turbine blade is 0.5:2.6. The inlet and outlet of the vertical cooling pipe 7 are alternately distributed, and the cooling gas flows in from the inlet, passes through the vertical cooling pipe 7, and flows out from the outlet. The cold gas flows through the vertical cooling pipe 7 to cool the blade surface.

[0032] The blades were modeled using Creo software, the fluid domain and solid domain were created in SpaceClaim, the mesh was drawn in FLUENT Meshing, the boundary conditions were set and simulated in CFX software, and finally the comparative experiment of result processing was conducted in CFD-Post. The optimal design dimensions that can be obtained are: 26 transverse cooling pipes 6 with a pipe diameter of 1.4mm are distributed on the pressure side and the suction side; 23 vertical cooling pipes 7 with a pipe diameter of 0.5mm are distributed on the pressure side and the suction side. The diameter of the transverse cooling pipe 6 set in the comparative experiment is 1.4mm, the diameter of the vertical cooling pipe 7 ranges from 0.5mm to 0.9mm, the number of vertical cooling pipes 7 on both sides is 18 to 33, and the number of transverse cooling pipes 6 (single type) on both sides is 13 to 23, that is, there are 13 to 23 transverse cooling pipes 6 connecting the first chamber 2 and the third chamber 4 and connecting the second chamber 3 and the fourth chamber 5. The total cooling gas flow rate is certain, which is 0.1435kg / s. The cooling air flow rate of the second chamber 3 is 0.0574kg / s, the cooling air flow rate of the third chamber 4 is 0.0574kg / s, and the total cooling air flow rate of the vertical pipeline inlet is 0.0287kg / s. For the optimization of the number of pipelines, when the number of pipelines is too small, the cooling gas is unevenly distributed and the temperature in the local area rises; when the number is too large, the flow resistance increases, resulting in a decrease in the cooling gas flow rate, which is not conducive to heat exchange. For the optimization of pipeline diameters, a smaller diameter can increase the cooling gas flow rate and enhance the convective heat transfer effect, but a too small diameter may cause the risk of flow blockage. The results of the simulation are shown in Tables 1, 2 and 3. Figure 3 As shown in the figure, it is the temperature cloud diagram of the traditional blade; Figure 4 As shown in Table 1, it is a temperature cloud diagram of the turbine blade adopting the horizontal and vertical pipeline cooling structure of the present invention. It can be seen from Table 1 to Table 3 that the present invention sets 26 horizontal cooling pipelines 6 and 23 vertical cooling pipelines 7 on both sides of the turbine blade, and the blade cooling effect is best when the corresponding pipe diameters are 1.4 mm and 0.5 mm respectively.

[0033] Table 1

[0034]

[0035]

[0036] Table 2

[0037]

[0038] Table 3

[0039]

[0040]

[0041] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A turbine blade adopting a horizontal and vertical pipeline cooling structure, comprising a leading edge air film hole (1) arranged at the leading edge of the blade and a trailing edge slit (8) arranged at the trailing edge of the blade, characterized in that: The invention also comprises a first chamber (2), a second chamber (3), a third chamber (4) and a fourth chamber (5) which are arranged in sequence inside the blade along the chord length direction of the blade body, wherein the first chamber (2) is close to the leading edge air film hole (1), and the fourth chamber (5) is close to the trailing edge split seam (8); a plurality of transverse cooling pipelines (6) and vertical cooling pipelines (7) are also arranged inside the blade; the two ends of the transverse cooling pipeline (6) are respectively connected to the corresponding chambers and are arranged perpendicular to the height direction of the blade, and the vertical cooling pipeline (7) is arranged along the height direction of the blade and passes through the blade.

2. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 1 is characterized in that: The transverse cooling pipeline (6) comprises two types, one connecting the first chamber (2) and the third chamber (4), and the other connecting the second chamber (3) and the fourth chamber (5).

3. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 2 is characterized in that: The two types of transverse cooling pipelines (6) are respectively distributed at equal intervals and staggered on the pressure side and the suction side of the blade.

4. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 3 is characterized in that: The number of the transverse cooling pipelines (6) on the pressure side and the suction side of the blade is 26, and the number of the two types of transverse cooling pipelines (6) is the same.

5. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 4 is characterized in that: The cross section of the transverse cooling pipeline (6) is circular.

6. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 5 is characterized in that: The ratio of the diameter of the transverse cooling pipeline (6) to the wall thickness of the blade pressure side is 1.4:3.6, and the ratio of the diameter of the transverse cooling pipeline (6) to the wall thickness of the blade suction side is 1.4:2.

6.

7. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 1 is characterized in that: The vertical cooling pipelines (7) are distributed at equal intervals along the profile direction of the pressure side and the suction side of the blade.

8. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 7 is characterized in that: The cross section of the vertical cooling pipeline (7) is circular.

9. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 8 is characterized in that: The number of the vertical cooling pipelines (7) on the pressure side and the suction side of the blade is 23.

10. The turbine blade adopting the horizontal and vertical pipeline cooling structure according to claim 9, characterized in that: The ratio of the pipe diameter of the vertical cooling pipeline (7) to the wall thickness of the blade pressure side is 0.5:3.6, and the ratio of the pipe diameter of the vertical cooling pipeline (7) to the wall thickness of the blade suction side is 0.5:2.6.

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