Spherical segment porous foam rib layer plate cooling structure applied to turbine blade

Abstract

The invention discloses a segment porous foam rib laminate cooling structure applied to turbine blades, which comprises a plurality of cooling units, and the plurality of cooling units are connected in series in any direction around one cooling unit by taking the cooling unit as the center to form the segment porous foam rib laminate cooling structure; wherein one cooling unit specifically comprises an impact pore plate and an air film pore plate which are arranged in parallel at an interval; the impact hole is formed in the center of the impact plate; the four air film hole channels are arranged at the four vertexes of the air film hole plate; the four turbulent flow columns are connected between the impact pore plate and the air film pore plate and are uniformly arranged around the impact pore in a surrounding manner; wherein the turbulent flow column is of a spherical porous foam rib structure; the impact holes, the gas film holes and the turbulent flow columns are all perpendicular to the flow direction of high-temperature fuel gas. According to the structure, the heat exchange intensity of the impact-gas film double-wall cooling technology is further improved.

Description

[Technical field]

[0001] The invention belongs to the technical field of turbine blade cooling, and in particular relates to a spherical porous foam rib plate cooling structure applied to turbine blades. [Background technology]

[0002] The power and efficiency of aircraft engines / gas turbines increase with the increase of turbine inlet gas temperature. The turbine inlet temperature of gas turbine engines currently in service has exceeded 1850K, far exceeding the heat resistance limit of blade high-temperature alloy materials (1150K), and the turbine inlet temperature of advanced gas turbine engines shows a trend of continuous increase. Therefore, in order to ensure the safe and reliable operation of turbine blades under high heat load conditions, efficient cooling measures must be taken.

[0003] The impingement-film double-wall cooling technology has attracted the attention of many researchers because it fully combines the advantages of internal impingement cooling and external film cooling. In the impingement / film double-wall film cooling structure, the cold air flows out from the impingement holes on the impingement plate and undergoes impingement heat exchange with the inner wall of the film plate, which significantly improves the heat exchange effect in the area near the stagnation point. Subsequently, the wall jet flows out from the film holes on the film plate and interacts with the mainstream high-temperature combustion gas to form film cooling, which avoids direct contact between the high-temperature combustion gas and the wall surface, thereby reducing the temperature of the outer surface of the blade. Compared with other single traditional internal convection cooling, impingement cooling, and film cooling methods, the impingement-film composite cooling technology can provide better cooling performance and higher cooling efficiency.

[0004] In order to further improve the internal impact cooling characteristics of the impact-air film double-wall cooling structure, different forms of rough spoiler elements will be arranged on the target surface (inner wall of the air film plate), and the common ones are spoiler columns, fins, and surface concave vortex generators. The arranged spoiler elements not only increase the mixing degree with the cooling gas flowing through the cooling channel, but also increase the surface area of ​​heat exchange, thereby increasing the heat exchange intensity of the inner wall of the air film plate in the layer plate structure. In high-performance cooling systems, existing spoiler elements such as spoiler columns and fins have limited ability to improve the heat transfer coefficient, mainly because they have insufficient destructive effect on the boundary layer, especially under low Reynolds number conditions. In order to overcome these problems, a new spoiler structure can be used to further enhance the turbulent mixing and heat exchange effects and improve the overall performance of the cooling system. [Summary of the invention]

[0005] The purpose of the present invention is to provide a spherical porous foam rib plate cooling structure applied to turbine blades, so as to further improve the heat exchange intensity of the impact-air film double-wall cooling technology.

[0006] The present invention adopts the following technical scheme: a spherical segment porous foam rib plate cooling structure applied to turbine blades, comprising a plurality of cooling units, with one cooling unit as the center, and a plurality of cooling units are connected in series in any direction around it to form a spherical segment porous foam rib plate cooling structure;

[0007] Wherein, a cooling unit specifically comprises:

[0008] An impact orifice plate and an air film orifice plate are arranged in parallel and at intervals, both of which are quadrilateral plate structures, and an impact channel is formed at the interval;

[0009] An impact hole, which is a cylindrical hole, is arranged at the center of the impact plate;

[0010] Four air film hole channels, all of which are 1 / 4 cylindrical holes, are set at the four vertices of the air film hole plate;

[0011] Four spoiler columns are connected between the impact hole plate and the air film hole plate and are evenly arranged around the impact hole;

[0012] Among them, the spoiler column is a spherical porous foam rib, which is a columnar structure formed by a plurality of porous single crystal cell arrays. The processing method of the structure of each porous single crystal cell is as follows: the six faces and eight vertices of the crystal cell cube are all spherically processed by a sphere, and the spherical grooves I on the six faces are all opened with columnar channels I toward the center of the cube, and the six columnar channels I are interconnected; the spherical grooves II on the eight vertices are all opened with columnar channels II, and the columnar channels II are connected with the columnar channels I to form an internal channel network;

[0013] Each impact hole, air film hole and spoiler column is perpendicular to the flow direction of the high-temperature combustion gas.

[0014] Furthermore, the radius of each spherical groove I is the same, and the radius of each spherical groove II is the same; the radius of the six cylindrical channels I is the same, and the radius of each cylindrical channel II is the same.

[0015] Furthermore, the impact holes and the film holes are cylindrical holes with an aperture of d, and are arranged in a direction perpendicular to the mainstream gas direction. The relative distances between adjacent impact holes along the flow direction and the span direction are 6d, and the relative distances between adjacent film holes 5 along the flow direction and the span direction are 6d.

[0016] Furthermore, the staggered spacing between the air film holes and the impact holes is 3d, the thickness of the impact hole plate and the air film hole plate are both 0.5 to 3d, and the height of the impact channel is 0.5 to 3d.

[0017] Furthermore, the cross-sectional shape of the spoiler column is circular, the distance between adjacent spoiler columns is 3d, and the ratio of the height of the spoiler column to the height of the impact channel is 0.25-1.

[0018] The beneficial effects of the present invention are as follows: the surface of the spherical porous foam rib structure usually has complex structures and pores, and these structures can effectively increase the contact surface area between the fluid and the spoiler column. Compared with a smooth surface, this spoiler column can provide more heat exchange surfaces, which is beneficial to the transfer and distribution of heat. At the same time, these irregular shapes and pore structures help to generate turbulence, and turbulence can increase the mixing degree of the fluid, thereby promoting heat transfer and greatly improving the heat exchange efficiency. At the same time, the spoiler column shape of the spherical porous foam rib structure is formed by additive manufacturing, with a lower density and higher specific strength. Therefore, the spoiler column can reduce weight while maintaining structural strength, and can withstand complex working environments under high temperature and high pressure. This makes it have excellent durability and reliability in aircraft engine turbine blades. Applying uniformly open-hole porous spoiler columns to aircraft engine blades can achieve multiple advantages such as lightweight design, improved strength and durability, and improved thermal conductivity.

Brief Description of the Drawings

[0019] Figure 1-1 It is a schematic diagram of the planar structure of a spherical porous foam rib plate cooling structure applied to turbine blades of the present invention;

[0020] Figure 1-2 It is a three-dimensional structural schematic diagram of a spherical porous foam rib plate cooling structure applied to turbine blades of the present invention;

[0021] Figure 2-1 It is a structural schematic diagram of a cooling unit of the present invention;

[0022] Figure 2-2 for Figure 2-1 Bottom view of

[0023] Figure 3-1 It is a schematic structural diagram of a spoiler column in a spherical porous foam rib plate cooling structure applied to turbine blades of the present invention;

[0024] Figure 3-2 for Figure 3-1 Schematic diagram of the structure of a mesoporous single cell;

[0025] Figure 4 It is a schematic diagram of the gas flow state in a spherical porous foam rib plate cooling structure applied to turbine blades of the present invention;

[0026] Figure 5 This is a comparison diagram of the average heat transfer coefficient of the target surface in the air film orifice plate in the embodiment;

[0027] Figure 6 This is a comparison diagram of the average wall temperatures of the inner and outer walls of the air film orifice plate in the embodiment;

[0028] Figure 7 It is a comparison chart of comprehensive cooling efficiency in the embodiments.

[0029] Among them, 1. impact hole, 2. impact orifice plate, 3. impact channel, 4. spoiler column, 5. air film hole, 6. air film orifice plate, 7. air film hole channel, 8. spherical groove I, 9. spherical groove II, 10. columnar channel I, 11. columnar channel II. [Specific implementation method]

[0030] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The present invention provides a spherical porous foam rib plate cooling structure for turbine blades, such as Figure 1-1 and Figure 1-2 As shown, it includes multiple cooling units, with one cooling unit as the center, and multiple cooling units are connected in series in any direction around it as needed to form a spherical porous foam rib plate cooling structure.

[0032] Among them, Figure 2-1 and Figure 2-2 As shown, a cooling unit specifically includes:

[0033] An impact orifice plate 2 and an air film orifice plate 6 are arranged in parallel and at intervals, both of which are quadrilateral plate structures, and an impact channel 3 is formed at the intervals;

[0034] An impact hole 1, which is a cylindrical hole, is arranged at the center of the impact plate 2;

[0035] The four air film hole channels 7 are all 1 / 4 cylindrical holes, which are arranged at the four vertices of the air film hole plate 6; the air film hole 5 appears as four 1 / 4 cylindrical holes in a cooling unit. When multiple cooling units are combined, the four 1 / 4 cylindrical holes are combined to form a complete air film hole 5.

[0036] Four spoiler columns 4 are connected between the impact hole plate 2 and the air film hole plate 6 and are evenly arranged around the impact hole 1;

[0037] like Figure 4 As shown, the impact hole plate 2 serves as an air inlet plate, and the cold flow enters from the impact hole 1; the air film hole plate 6 serves as an air outlet plate, and the air is discharged from the air film hole 5, thereby completing the cold air coverage.

[0038] Among them, Figure 3-1 and Figure 3-2As shown, the spoiler column 4 is a spherical-notch porous foam rib, which is a columnar structure formed by an array of multiple porous single crystal cells, and the processing method of the structure of each porous single crystal cell is as follows: the six faces and eight vertices of the crystal cell cube are all spherically notched through a sphere, and the spherical grooves I8 on the six faces are all opened with columnar channels I10 toward the center of the cube, and the six columnar channels I10 are interconnected; the spherical grooves II9 on the eight vertices are all opened with columnar channels II11, and the columnar channels II11 are connected with the columnar channels I10 to form a complex internal channel network; the spherical-notch treatment and the internal columnar channels can effectively disperse the pressure generated during the fluid flow process, thereby reducing the overall fluid resistance, and can increase the contact area between the fluid and the spoiler column surface, thereby improving the heat exchange efficiency.

[0039] Each impact hole 1, air film hole 5 and spoiler column 4 is perpendicular to the flow direction of the high-temperature combustion gas.

[0040] In some embodiments, the radius of each spherical groove I8 is the same, and the radius of each spherical groove II9 is ​​the same; the radius of the six cylindrical channels I10 is the same, and the radius of each cylindrical channel II is the same. This setting can form a uniform open-pore porous structure, which can simplify the manufacturing process and can adapt to a variety of manufacturing technologies. In computer simulation and analysis, consistent design parameters make the optimization process simpler and make it easier to find the best design solution.

[0041] In some embodiments, the impact hole 1 and the air film hole 5 are both cylindrical holes with an aperture of d, and are arranged in a direction perpendicular to the mainstream gas direction. The relative distances between adjacent impact holes 1 along the flow direction and the span direction are both 6d, and the relative distances between adjacent air film holes 5 along the flow direction and the span direction are both 6d.

[0042] In some embodiments, the staggered spacing between the air film holes 5 and the impact holes 1 is 3d, the thickness of the impact hole plate 2 and the air film hole plate 6 are both 0.5 to 3d, and the height of the impact channel 3 is 0.5 to 3d.

[0043] In some embodiments, the cross-sectional shape of the spoiler column 4 is circular, the distance between adjacent spoiler columns 4 is 3d, and the ratio of the height of the spoiler column 4 to the height of the impact channel 3 is 0.25-1.

[0044] In the present invention, the cooling airflow passes through the impact orifice plate 2, blows out from the impact hole 1 into the impact channel 3 between the double walls to impact the target surface for heat exchange, and then forms a wall jet around. The spoiler column 4 strengthens the disturbance of the cooling airflow and increases the specific surface area, thereby enhancing the heat exchange. Due to the structural characteristics of the porous spoiler column, although the flow resistance of the cooling structure is increased and the pressure loss of the cooling airflow is increased, the flow loss of the cooling airflow can be accepted while greatly enhancing the heat exchange effect. Then the cooling airflow enters the air film hole 5 for convective heat exchange, and finally blows to the outer wall of the air film orifice plate 6 to form an air film, thereby preventing the high-temperature combustion gas from ablating the air film orifice plate.

[0045] Example

[0046] A spherical porous foam rib plate cooling structure applied to turbine blades in this example is applied to the mid-chord area of ​​the gas turbine blades of aircraft engines. It consists of an impact hole 1, an impact hole plate 2, an impact channel 3 between double-layer walls, a spoiler column 4 with uniform openings and multiple holes, an air film hole 5 and an air film hole plate 6. The impact hole plate 2 is an air inlet plate, close to the cold air side, and a number of impact holes perpendicular to the mainstream airflow direction are evenly and equidistantly arranged on the plate, the impact hole aperture d is 10mm, and the relative distance between the impact holes along the flow direction and the span direction is 6d; the air film hole plate is an air outlet plate, the air film hole plate is close to the gas side, and a number of air film holes perpendicular to the mainstream airflow direction are arranged on the plate, the air film hole aperture is also d, and the relative distance between the air film holes along the flow direction and the span direction is 6d, and the air film holes and the impact holes are staggered and arranged, with a spacing of 3d, and the thickness of the perforated plate and the air film hole plate is 1d; the impact distance, that is, the ratio of the distance between the impact hole and the impact target surface to the impact hole diameter d is 1. The impact holes and air film holes are cylindrical holes. The four air film hole channels are all 1 / 4 air film holes. Four air film hole channels, four spoiler columns and an impact hole constitute a basic cooling unit. The spoiler columns are arranged in the cooling channel formed by the air film hole plate and the impact hole plate. The relative position is located around the air film hole. The relative distance of the spoiler columns along the flow direction and the span direction is 3d, and they are arranged in an alternating manner with the air film holes and the impact holes; the span width of the air film hole plate and the impact hole plate is 6d, the spoiler column is cylindrical, and the ratio of the spoiler column height to the impact channel height is 1.

[0047] In this embodiment, for the porous medium area, a modeling method based on the characterization volume scale (REV) porous medium is proposed to describe the flow and heat transfer process inside the porous medium turbulence element. The porous medium turbulence element used in the simulation is homogeneous and isotropic, and the influence of natural convection, radiation heat transfer of the fluid and the contact thermal resistance between the porous medium turbulence element and the wall are ignored. The uniform open-pore turbulence column is formed by a unit crystal spore array, and the holes are connected by cylindrical open channels. The porosity is changed by changing the radius of the cylinder and the distance between the centers of the radii of adjacent spheres.

[0048] For the spherical segment model, the pores are connected by cylindrical open channels, and the porosity is changed by changing the radius of the cylinder and the distance between the radius and center of the adjacent sphere. In this embodiment, the viscosity loss coefficient is consistent with the inertia loss coefficient, and the porosity of the porous medium is changed. ε The effective thermal conductivity of porous media is calculated by λ e =ελ f +(1-ε)λ s Calculate,λ f is the thermal conductivity of the fluid, λ s is the solid thermal conductivity. The fluid is an ideal gas, air, and the fluid thermal conductivity λ f Assigned by linear interpolation, the solid plate material is steel, and the solid thermal conductivity is λ s It is 16.27w / (m·K).

[0049] Compare SFP and Solid in the prior art with three solutions Porous0.7, Porous0.8 and Porous0.9 in this embodiment. SFP represents a layer plate structure without spoiler columns, and Solid represents a traditional solid spoiler column layer plate structure.

[0050] like Figure 5 As shown in the comparison diagram of the average heat transfer coefficient of the target surface inside the air film orifice plate, the average heat transfer coefficient of the target surface inside the air film orifice plate of the three groups of schemes, Porous0.7, Porous0.8 and Porous0.9, is significantly improved compared with the SFP and Solid schemes in the prior art, indicating that the spherical porous foam rib plate cooling structure applied to turbine blades of the present invention shows significant advantages in improving cooling performance.

[0051] like Figure 6 As shown in the comparison chart of the average wall temperature of the inner and outer walls of the air film orifice plate, the average wall temperature of the inner and outer walls of the air film orifice plate of the three schemes of Porous0.7, Porous0.8 and Porous0.9 is lower than that of the two schemes of SFP and Solid in the prior art. The uniform temperature distribution and efficient heat conduction path make the wall temperature more uniform and avoid local overheating. This shows that the spherical porous foam rib plate cooling structure applied to turbine blades of the present invention has better protection for the blade surface.

[0052] like Figure 7 As shown in the comprehensive cooling efficiency comparison chart, the average wall temperature of the inner and outer walls of the air film orifice plates of the three schemes of Porous0.7, Porous0.8 and Porous0.9 are significantly improved compared with the SFP and Solid schemes in the existing technology. The improvement ratio is nearly 12% to 16% compared with SFP, which is significantly better than the non-spoiler structure and traditional spoiler column.

[0053] In summary, these results show that the spherical porous foam rib plate cooling structure applied to turbine blades of the present invention is an efficient and reliable cooling solution, which is suitable for occasions requiring high-performance cooling, such as aerospace engines, high-temperature industrial equipment, etc. Further improving the heat exchange benefits brought by the increase in the effective heat exchange area of ​​the spoiler target plate, and designing a cooling structure with excellent heat exchange characteristics and a low flow resistance coefficient without increasing the cold air flow rate, is of great significance for the safe and stable operation of the blades.

[0054] The surface of the spherical porous foam rib structure used in the present invention usually has complex structures and pores, which can effectively increase the contact surface area between the fluid and the spoiler column. Compared with a smooth surface, this spoiler column can provide more heat exchange surfaces, which is beneficial to the transfer and distribution of heat. At the same time, these irregular shapes and pore structures help to generate turbulence, and turbulence can increase the mixing degree of the fluid, thereby promoting the transfer of heat and greatly improving the heat exchange efficiency. When the jet flows through the middle of the porous ribs, heat transfer occurs between the porous ribs of the open-pore structure and the fluid: on the one hand, the internal three-dimensional reticular structure enhances the turbulence intensity of the fluid in the foam ribs, thereby enhancing convective heat transfer; on the other hand, the large specific surface area and high thermal conductivity in the porous foam ribs also promote the transfer of heat from the high-temperature fuel gas side to the cooling gas side, thereby enhancing the heat conduction effect.

[0055] At the same time, the spoiler column of the spherical porous foam rib structure is formed by additive manufacturing, which has a lower density and higher specific strength. Therefore, the spoiler column can reduce weight while maintaining structural strength and can withstand complex working environments under high temperature and high pressure. This makes it have excellent durability and reliability in aircraft engine turbine blades. Applying uniformly open porous spoiler columns to aircraft engine blades can achieve multiple advantages such as lightweight design, improved strength and durability, and improved thermal conductivity.

[0056] In addition, after porous foam ribs are set on the wall of the impact target plate, the heat transfer performance of the low heat transfer area between adjacent impact holes on the impact target plate in traditional impact cooling is improved, thereby improving the heat transfer uniformity of the impact target plate wall. Therefore, without increasing the cold air flow rate, by reasonably adjusting the pore / rib structure parameters such as the porosity, pore density, and rib height of the porous foam ribs, the internal impact convection heat transfer of the layer structure and the heat conduction of the local high temperature area of ​​the air film plate are strengthened, thereby fully improving the cooling performance of the porous foam rib layer structure.

Claims

1. A spherical porous foam rib plate cooling structure applied to turbine blades, characterized in that: It comprises a plurality of cooling units, with one cooling unit as the center, and a plurality of cooling units are connected in series in any direction around it to form the spherical porous foam rib plate cooling structure; Wherein, one of the cooling units specifically comprises: An impact orifice plate (2) and an air film orifice plate (6) are arranged in parallel and at intervals, both of which are quadrilateral plate structures, and an impact channel (3) is formed at the intervals; An impact hole (1), which is a cylindrical hole, is arranged at the center of the impact plate (2); Four air film hole channels (7), all of which are 1 / 4 cylindrical holes, are arranged at four vertices of the air film hole plate (6); Four spoiler columns (4) are connected between the impact hole plate (2) and the air film hole plate (6) and are evenly arranged around the impact hole (1); The spoiler column (4) is a spherical porous foam rib, which is a columnar structure formed by an array of multiple porous single crystal cells, and the processing method of the structure of each porous single crystal cell is as follows: the six faces and eight vertices of the crystal cell cube are all spherically processed by a sphere, and the spherical grooves I (8) on the six faces are all opened with columnar channels I (10) toward the center of the cube, and the six columnar channels I (10) are interconnected; the spherical grooves II (9) on the eight vertices are all opened with columnar channels II (11), and the columnar channels II (11) are connected with the columnar channels I (10) to form an internal channel network; Each of the impact holes (1), the air film holes (5) and the spoiler columns (4) is perpendicular to the flow direction of the high-temperature combustion gas.

2. A spherical porous foam rib plate cooling structure for turbine blades as claimed in claim 1, characterized in that: The radius of each of the spherical grooves I (8) is the same, and the radius of each of the spherical grooves II (9) is the same; the radius of the six cylindrical channels I (10) is the same, and the radius of each of the cylindrical channels II is the same.

3. A spherical porous foam rib plate cooling structure applied to turbine blades as claimed in claim 1 or 2, characterized in that: The impact holes (1) and the air film holes (5) are both cylindrical holes with a hole diameter of d, and are arranged in a direction perpendicular to the mainstream gas direction. The relative distances between adjacent impact holes (1) along the flow direction and the span direction are both 6d, and the relative distances between adjacent air film holes 5 along the flow direction and the span direction are both 6d.

4. A spherical porous foam rib plate cooling structure for turbine blades as claimed in claim 3, characterized in that: The staggered spacing between the air film holes (5) and the impact holes (1) is 3d, the thickness of the impact hole plate (2) and the air film hole plate (6) are both 0.5 to 3d, and the height of the impact channel (3) is 0.5 to 3d.

5. The spherical porous foam rib plate cooling structure applied to turbine blades as claimed in claim 3, characterized in that: The cross-sectional shape of the spoiler column (4) is circular, the distance between adjacent spoiler columns (4) is 3d, and the ratio of the height of the spoiler column (4) to the height of the impact channel (3) is 0.25-1.

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