A variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane

Abstract

The present invention discloses a variable aperture impact cooling structure applied to the suction surface of a turbine guide vane, comprising a plurality of impact thin plates, any two adjacent impact thin plates are connected by a partition rib, a plurality of rows of impact holes are provided on the top of the impact thin plates, a spoiler is installed between any two adjacent rows of impact holes, one end of the spoiler abuts against the partition rib, a plurality of impact cavities are provided in the impact thin plate, an impact target surface is provided on one side of the impact thin plate perpendicular to the partition rib, a cold air outlet is provided at one end of the impact target surface, and the cold air outlet is located in the impact cavity. The present invention has the characteristics of simple method, convenient processing, and obvious effect, and can be applied to various internal impact structures of the suction surface of turbine blades.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine turbine blade cooling, and in particular to a variable aperture impingement cooling structure applied to a turbine guide vane suction surface. Background Art

[0002] Gas turbine engine is a thermal power device based on Brayton cycle. It has been widely used in modern military and industry due to its powerful output power and high thermal efficiency. Experience shows that under the premise of unchanged engine size, the thrust of gas turbine can be increased by 8-13% and the cycle efficiency can be increased by 2-4% for every 56K increase in turbine inlet temperature. At present, the turbine inlet temperature of advanced aircraft engines has exceeded 2000K, while the temperature resistance limit of turbine blade materials is much lower than the turbine inlet temperature. Therefore, high-efficiency cooling technology must be adopted to ensure its normal operation. There are flow separation and transition phenomena in the downstream area of ​​the suction surface of the turbine guide vane, and the convective heat transfer intensity is high. It is the area with the highest heat load except the leading edge and trailing edge. In addition, the suction surface of the guide vane is a thin-walled structure with a large area. Excessive temperature or large temperature gradient may cause the suction surface structure to be damaged, affecting the normal operation of the turbine. Therefore, the cooling design of the suction surface area requires not only a large cooling amount, but also good cooling uniformity. It is a key and difficult area for cooling design on turbine blades.

[0003] The suction surface area of ​​the turbine guide vane is generally cooled by internal impingement cooling. Impingement cooling is achieved by adding a thin plate with an array of impingement holes inside the blade. The cold air flows from the internal cavity through the impingement holes on the thin plate to form an impingement jet. After the jet impacts the wall, due to the sharp flow turning and speed change, a local high heat exchange area will be generated on the impact target surface. At the same time, in order to support the impingement thin plate, a plurality of supporting rib structures are usually arranged between the impingement thin plate and the inner surface of the blade to divide a plurality of impingement cavity structures. As mentioned above, due to the large area of ​​suction surface impingement cooling, a single impingement cavity often requires a plurality of impingement holes to form an array structure to enhance the overall heat exchange intensity of the inner surface of the blade. However, the cold air after the array impingement will converge toward the outlet direction to form the so-called cross flow, which affects the impingement effect on the one hand, and also causes the heat exchange intensity along the flow direction to change, which is not conducive to reducing the temperature gradient of the suction surface. Therefore, it is very necessary and meaningful to develop and improve the array impingement structure on the suction surface side to improve the heat exchange uniformity of the inner surface of the suction surface without increasing the amount of cold air, in order to further improve the performance of aircraft engines.

[0004] In summary, how to design an impact cooling structure that changes the impact flow direction, reduces the unevenness of heat exchange in the impact target flow direction, reduces the temperature gradient level of the suction surface, and has a simple method and convenient processing is an urgent problem to be solved in this field. Summary of the invention

[0005] The object of the present invention is to provide a variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a variable aperture impact cooling structure applied to the suction surface of a turbine guide vane, comprising a plurality of impact thin plates, any two adjacent impact thin plates are connected by a partition rib, a plurality of rows of impact holes are provided on the top of the impact thin plates, a spoiler is installed between any two adjacent rows of the impact holes, one end of the spoiler is in contact with the partition rib, a plurality of impact cavities are provided in the impact thin plate, an impact target surface is provided on one side of the impact thin plate perpendicular to the partition rib, a cold air outlet is provided at one end of the impact target surface, and the cold air outlet is located in the impact cavity.

[0007] Preferably, the spoiler portion includes a first spoiler rib fixedly connected to the top of the impact thin plate, a second spoiler rib is abutted against one side of the first spoiler rib, and the first spoiler rib and the second spoiler rib are respectively perpendicular to the partition rib and arranged in a staggered manner.

[0008] Preferably, the first spoiler rib and the second spoiler rib are both wavy in shape.

[0009] Preferably, an outlet spoiler column is symmetrically fixed to and connected to the top of the impact thin plate, and the outlet spoiler column is located on a side of the impact hole away from the second spoiler rib.

[0010] Preferably, a blade suction surface substrate is provided at the bottom of the impact thin plate, and the impact cavity is located above the blade suction surface substrate.

[0011] Preferably, the equivalent uniform diameter of the impact holes converted into equal number and equal total area is d0, the aperture of the first row of the impact holes along the flow direction is d1, and the aperture of the last row of holes is d2.

[0012] Preferably, the ratio of the thickness t of the impact thin plate to the d0 is 0.5-1, and the ratio of the distance H between the impact thin plate and the impact target surface to the d0 is 1-3.

[0013] Preferably, the aperture ratio d1 / d2 of the first row of holes and the last row of holes along the flow direction of the impact holes is 1.1-1.3.

[0014] Preferably, the ratio of the spanwise hole spacing of the impact holes p to the d0 is 3-6, and the ratio of the flowwise hole spacing of the impact holes s to the d0 is 6-15.

[0015] The present invention discloses the following technical effects: by adjusting the diameter distribution of the impact holes on the impact thin plate, changing the impact heat exchange intensity distribution of each row of impact holes, arranging the spoiler in the weak impact heat exchange area along the flow direction, it is beneficial to achieve a uniform heat exchange distribution effect, thereby reducing the uneven temperature distribution of the impact target surface and improving the blade life. The present invention has the characteristics of simple method, convenient processing and obvious effect, and can be applied to various internal impact structures of the suction surface of turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is an axonometric view of the present invention;

[0018] Figure 2 A top view of the present invention;

[0019] Figure 3 For the present invention Figure 2 AA section view;

[0020] Figure 4 For the present invention Figure 2 BB cross-sectional view;

[0021] Figure 5 It is a left side view of the present invention;

[0022] Figure 6 For the present invention Figure 5 CC map;

[0023] Figure 7 For the present invention Figure 5 DD diagram;

[0024] Figure 8 The spanwise average heat transfer coefficient curves of the uniform aperture impact cooling structure and the variable aperture impact cooling structure at different flow direction positions on the impact target surface;

[0025] Among them, 1. impact thin plate; 2. impact hole; 3. cold air outlet; 4. impact cavity; 5. impact target surface; 6. separation rib; 7. blade suction surface base; 8. outlet spoiler column; 9. first spoiler rib; 10. second spoiler rib. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figure 1-7 The present invention provides a variable aperture impact cooling structure applied to the suction surface of a turbine guide vane, comprising a plurality of impact thin plates 1, any two adjacent impact thin plates 1 are connected by a partition rib 6, a plurality of rows of impact holes 2 are provided on the top of the impact thin plates 1, a spoiler is installed between any two adjacent rows of impact holes 2, one end of the spoiler abuts against the partition rib 6, a plurality of impact cavities 4 are provided in the impact thin plate 1, an impact target surface 5 is provided on one side of the impact thin plate 1 perpendicular to the partition rib 6, a cold air outlet 3 is provided at one end of the impact target surface 5, and the cold air outlet 3 is located in the impact cavity 4.

[0029] One side of the impact hole 2 is a cold air inlet, and the other side is a hole outlet. After the cold air flows out of the hole, it impacts the impact target surface 5 and then flows out through the cold air outlet 3. The impact hole 2 is a cylindrical hole. Along the flow direction of the cold air in the impact cavity, the diameter of each row of impact holes gradually changes. By adjusting the diameter distribution of the impact holes 2 on the impact plate 1, the impact heat exchange intensity distribution of each row of impact holes 2 is changed, and the spoiler is arranged in the weak impact heat exchange area along the flow direction, which is conducive to achieving a uniform heat exchange distribution effect, thereby reducing the unevenness of the temperature distribution of the impact target surface 5 and improving the life of the blade. The present invention has the characteristics of simple method, convenient processing, and obvious effect, and can be applied to various internal impact structures of the suction surface of turbine blades.

[0030] According to a further optimized solution, the spoiler portion includes a first spoiler rib 9 fixedly connected to the top of the impact plate 1, a second spoiler rib 10 abuts against one side of the first spoiler rib 9, and the first spoiler rib 9 and the second spoiler rib 10 are respectively perpendicular to the partition rib 6 and are staggered.

[0031] In a further optimized solution, the first spoiler rib 9 and the second spoiler rib 10 are both wavy. The first spoiler rib 9 and the second spoiler rib 10 are perpendicular to the flow direction and are located between the two rows of impact holes 2; the spacing p between the first spoiler rib 9 and the second spoiler rib 10 is r is 4.0mm, distance H r 1.0mm, height e r is 0.5mm and the length λ is 2.8mm.

[0032] Further optimization scheme, the top of the impact thin plate 1 is symmetrically fixed and connected with an outlet spoiler column 8, and the outlet spoiler column 8 is located on the side of the impact hole 2 away from the second spoiler rib 10. The outlet spoiler column 8 is located at the inlet and outlet of the channel, and the aperture d of the outlet spoiler column 8 is p The outlet spoiler column spacing p is 1.0 mm. p It is 2.8mm.

[0033] According to a further optimized solution, a blade suction surface matrix 7 is provided at the bottom of the impact thin plate 1 , and the impact cavity 4 is located above the blade suction surface matrix 7 .

[0034] In this embodiment, the cold air from the inside of the turbine blade enters the impact cavity 4 through the impact hole 2, and the jet impacts the impact target surface 5 to strengthen the heat exchange effect on this side, thereby reducing the temperature of the blade suction surface substrate 7 without further reducing the temperature of the cold air. Since the cold air in the impact cavity 4 converges and flows out to the cold air outlet 3, the cold air will form a so-called cross-flow flow, which affects the impact effect on the one hand, and also causes the heat exchange intensity along the flow direction M to change, which is not conducive to reducing the temperature gradient of the blade suction surface substrate 7. By adjusting the diameter of the impact holes 2 of different hole rows along the flow direction, the impact heat exchange intensity of different hole rows can be changed, and a more uniform impact heat exchange distribution of the impact target surface 5 can be achieved, thereby reducing the unevenness of the temperature distribution of the blade suction surface substrate 7.

[0035] According to a further optimization scheme, the equivalent uniform diameter of the impact holes 2 converted into equal number and equal total area is d0, the aperture of the first row of holes of the impact holes 2 along the flow direction is d1, and the aperture of the last row of holes is d2.

[0036] According to a further optimization scheme, the ratio of the thickness t of the impact thin plate 1 to d0 is 0.5-1, and the ratio of the distance H between the impact thin plate 1 and the impact target surface 5 to d0 is 1-3.

[0037] According to a further optimization scheme, the aperture ratio d1 / d2 of the first row of holes and the last row of impact holes 2 along the flow direction is 1.1-1.3.

[0038] According to a further optimization scheme, the ratio of the spanwise hole spacing of the impact hole 2 to p and d0 is 3-6, and the ratio of the flowwise hole spacing of the impact hole 2 to s and d0 is 6-15.

[0039] In this embodiment, the aperture d1 of the first row of impact holes 2 along the flow direction is 0.55 mm, the aperture d2 of the last row of holes is 0.65 mm, the diameter d0 of the equivalent impact hole is 0.6 mm, the thickness t of the impact plate 1 is 2.7 mm, the distance H between the impact plate 1 and the impact target surface 5 is 0.8 mm, and the spanwise hole spacing of the impact hole 2 is p h It is 2.7mm, and the flow hole spacing s of the impact hole 2 is 4mm.

[0040] The working principle of the present invention is as follows: the cooling airflow from the internal channel of the turbine blade enters from the impact hole 2 on the impact thin plate 1, impacts the impact target surface 5, and then flows out from the cold air outlet 3. By controlling the aperture distribution of the impact hole 2 and arranging the first spoiler rib 9 and the second spoiler rib 10 and the outlet spoiler column 8 in the channel, the uniformity of the distribution of the heat transfer coefficient on the inner surface of the pressure surface is improved and the temperature distribution gradient of the pressure surface is reduced.

[0041] In order to verify the effectiveness of the present invention, the heat transfer coefficient of the impact target surface 5 using a uniform aperture impact cooling structure and a variable aperture impact cooling structure was calculated. The difference between the two structures is only the change in the diameter of the impact hole 2, and the total area and number of impact holes 2 corresponding to a single impact cavity 4 remain unchanged. The calculation process uses UG modeling, ICEM generates unstructured grids, and CFX solver is used for solving.

[0042] Figure 8 The blade impact target surface 5 along the flow direction ( Figure 2 The span direction (M direction) Figure 2 N direction) average heat transfer coefficient h f Distribution. The horizontal axis represents the distance in the flow direction, and the vertical axis represents the span-wise average film cooling efficiency. The average heat transfer coefficient has peak values ​​and low values. The peak value corresponds to the jet impact position, and the low value corresponds to the middle area of ​​the two rows of holes along the flow direction M. It can be seen that the average heat transfer coefficient peak value of the conventional uniform aperture impact cooling structure gradually increases along the flow direction, while the average heat transfer coefficient peak value of the variable aperture impact cooling structure with this embodiment at different flow direction positions is more uniform. This fully demonstrates the effectiveness and superiority of this patent.

[0043] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply 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 understood as a limitation on the present invention.

[0044] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane, characterized in that: The invention comprises a plurality of impact thin plates (1), any two adjacent impact thin plates (1) are connected by a partition rib (6), a plurality of rows of impact holes (2) are provided on the top of the impact thin plates (1), a spoiler is installed between any two adjacent rows of impact holes (2), one end of the spoiler is in contact with the partition rib (6), a plurality of impact cavities (4) are provided in the impact thin plates (1), an impact target surface (5) is provided on one side of the impact thin plates (1) perpendicular to the partition rib (6), a cold air outlet (3) is provided at one end of the impact target surface (5), and the cold air outlet (3) is located in the impact cavity (4); The spoiler portion comprises a first spoiler rib (9) fixedly connected to the top of the impact thin plate (1), a second spoiler rib (10) abutting against one side of the first spoiler rib (9), and the first spoiler rib (9) and the second spoiler rib (10) are respectively perpendicular to the partition rib (6) and arranged in a staggered manner; The first spoiler rib (9) and the second spoiler rib (10) are both wavy in shape; An outlet spoiler column (8) is symmetrically fixed to and connected to the top of the impact thin plate (1), and the outlet spoiler column (8) is located on a side of the impact hole (2) away from the second spoiler rib (10); Along the flow direction of cold air in the impact cavity, the diameter of each row of impact holes changes gradually, and the aperture ratio d1 / d2 of the first row of holes and the last row of impact holes (2) along the flow direction is 1.1-1.

3.

2. The variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane according to claim 1 is characterized in that: A blade suction surface base (7) is provided at the bottom of the impact thin plate (1), and the impact cavity (4) is located above the blade suction surface base (7).

3. The variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane according to claim 1 is characterized in that: The equivalent uniform diameter of the impact holes (2) converted into equal number and equal total area is d0.

4. The variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane according to claim 3 is characterized in that: The ratio of the thickness t of the impact thin plate (1) to the d0 is 0.5 to 1, and the ratio of the distance H between the impact thin plate (1) and the impact target surface (5) to the d0 is 1 to 3.

5. The variable aperture impingement cooling structure applied to the suction surface of a turbine guide vane according to claim 3, characterized in that: The ratio of the spanwise hole spacing p of the impact holes (2) to the d0 is 3 to 6, and the ratio of the flowwise hole spacing s of the impact holes (2) to the d0 is 6 to 15.

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