A spherical hollow multi-hole foam ribbed panel cooling structure applied to a turbine blade

Abstract

The application discloses a kind of spherical segment porous foam ribbed panel cooling structure applied to turbine blade, including multiple cooling units, with one cooling unit as center, multiple cooling units are connected in series in any direction to its four directions, to form spherical segment porous foam ribbed panel cooling structure;Wherein, one cooling unit specifically includes: one impingement orifice plate and one film hole plate are arranged in parallel and are spaced apart;One impingement hole is arranged at the center position of impingement plate;Four film hole channels are arranged at the four vertices of film hole plate;Four spoiler columns are connected and arranged between impingement orifice plate and film hole plate, and are uniformly arranged around the four peripheries of impingement hole;Wherein, spoiler column is spherical segment porous foam rib structure;Each impingement hole, film hole and spoiler column are perpendicular to the flow direction of high-temperature gas.The structure further improves the heat exchange intensity of impingement-film double-wall cooling technology.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of turbine blade cooling, and particularly relates to a spherical segment porous foam ribbed panel cooling structure applied to a turbine blade. BACKGROUND

[0002] The power and efficiency of an aero-engine / gas turbine increase with the increase of turbine inlet gas temperature. The turbine inlet temperature of the currently serving gas turbine engine has exceeded 1850K, far exceeding the heat resistance limit (1150K) of the blade high-temperature alloy material, and the turbine inlet temperature of the advanced gas turbine engine presents a trend of continuous increase. Therefore, in order to ensure the safe and reliable work of the turbine blade under high heat load conditions, efficient cooling measures must be taken.

[0003] The impingement-film double-wall cooling technology has attracted much attention of many researchers due to its full combination of the advantages of internal impingement cooling and external film cooling. In the impingement / film double-wall film cooling structure, the cold gas flows out of the impingement hole on the impingement plate and impinges on the inner wall of the film plate, so that the heat exchange effect of the region near the stagnation point is significantly improved. Then the wall jet flows out of the film hole on the film plate and interacts with the high-temperature gas flow, forming a film cooling, avoiding the direct contact of the high-temperature gas with the wall, and playing a role in 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 impingement cooling characteristics of the impingement-film double-wall cooling structure, different forms of rough disturbance elements are arranged on the target surface (the inner wall surface of the film plate), and the common ones are disturbance columns, ribs, surface recess vortex generators. The arranged disturbance elements not only increase the mixing degree of the cooling gas flowing through the cooling channel, but also increase the heat exchange surface area, thereby increasing the heat exchange intensity of the inner wall surface of the film plate in the panel structure. In the high-performance cooling system, the existing disturbance elements such as disturbance columns and ribs have limited ability to improve the heat exchange coefficient, mainly because they have insufficient effect on the destruction of the boundary layer, especially under low Reynolds number conditions. In order to overcome these problems, new disturbance structures can be used to further enhance the turbulent mixing and heat exchange effect and improve the overall performance of the cooling system. SUMMARY

[0005] The purpose of the application is to provide a spherical segment porous foam ribbed panel cooling structure applied to a turbine blade, so as to further improve the heat exchange intensity of the impingement-film double-wall cooling technology.

[0006] The application adopts the following technical scheme: a spherical segment porous foam ribbed panel cooling structure applied to a turbine blade, comprising a plurality of cooling units, with one cooling unit as a center, a plurality of cooling units are connected in series in any direction around the center to form the spherical segment porous foam ribbed panel cooling structure;

[0007] The one cooling unit specifically comprises:

[0008] A shock hole plate and a film hole plate are arranged in parallel and at intervals, both are quadrilateral plate structures, and a shock passage is formed at the interval;

[0009] The one shock hole is a cylindrical hole arranged at the center position of the shock plate;

[0010] The four film hole passages are all 1 / 4 cylindrical holes arranged at the four vertexes of the film hole plate;

[0011] The four spoiler columns are connected and arranged between the shock hole plate and the film hole plate and are uniformly arranged around the four sides of the shock hole;

[0012] The spoiler column is a spherical segment porous foam rib, which is formed into a columnar structure by a plurality of porous single cell arrays, and the structure of each porous single cell is processed in the following manner: the six faces and eight vertexes of the cubic cell are all subjected to spherical segment processing by a sphere, the spherical grooves I on the six faces are all provided with a cylindrical passage I towards the center of the cubic cell, and the six cylindrical passages I are in communication with each other; the spherical grooves II on the eight vertexes are all provided with a cylindrical passage II, the cylindrical passage II is in communication with the cylindrical passage I and forms an internal passage network;

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

[0014] Further, the radius of each spherical groove I is the same, the radius of each spherical groove II is the same, the radius of the six cylindrical passages I is the same, and the radius of each cylindrical passage II is the same.

[0015] Further, the shock hole and the film hole are both cylindrical holes with a hole diameter d, and are arranged in a direction perpendicular to the direction of the main gas flow, the relative distance between adjacent shock holes along the flow direction and the spanwise direction is 6d, and the relative distance between adjacent film holes 5 along the flow direction and the spanwise direction is 6d.

[0016] Further, the staggered distance between the film hole and the shock hole is 3d, the thickness of the shock hole plate and the film hole plate is 0.5-3d, and the height of the shock passage is 0.5-3d.

[0017] Further, 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 shock passage is 0.25-1.

[0018] The beneficial effects of the present application are: the surface of the spherical hollow porous foam rib structure generally has complex structures and pores, which can effectively increase the contact surface area between the fluid and the turbulence column. Compared with a smooth surface, such turbulence column can provide more heat exchange surface, which is beneficial to heat transfer and distribution. At the same time, these irregular shapes and pore structures help to generate turbulence, which can increase the mixing degree of the fluid, thereby promoting heat transfer and greatly improving heat exchange efficiency. At the same time, the turbulence column shape of the spherical hollow porous foam rib structure is formed by additive manufacturing, which has a low density and a high specific strength, so that the turbulence 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 the turbine blades of an aero-engine. The application of uniform porous turbulence column to the aero-engine blades can realize lightweight design, improve strength and durability, and improve thermal conductivity. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1-1 A planar structure diagram of a spherical hollow porous foam rib layer plate cooling structure applied to a turbine blade of the present application;

[0020] Figure 1-2 A three-dimensional structure diagram of a spherical hollow porous foam rib layer plate cooling structure applied to a turbine blade of the present application;

[0021] Figure 2-1 A structure diagram of a cooling unit of the present application;

[0022] Figure 2-2 A bottom view of Figure 2-1 ;

[0023] Figure 3-1 A structure diagram of a turbulence column in a spherical hollow porous foam rib layer plate cooling structure applied to a turbine blade of the present application;

[0024] Figure 3-2 A structure diagram of a porous single cell in Figure 3-1 ;

[0025] Figure 4 A gas flow state diagram in a spherical hollow porous foam rib layer plate cooling structure applied to a turbine blade of the present application;

[0026] Figure 5 A comparison diagram of the average heat exchange coefficient of the target surface in the gas film hole plate in the embodiment;

[0027] Figure 6 A comparison diagram of the average wall temperature of the inner and outer wall surfaces of the gas film hole plate in the embodiment;

[0028] Figure 7 A comparison diagram of the comprehensive cooling efficiency in the embodiment.

[0029] Wherein, 1. impact hole, 2. impact hole plate, 3. impact channel, 4. spoiler column, 5. film hole, 6. film hole plate, 7. film hole channel, 8. spherical groove I, 9. spherical groove II, 10. cylindrical channel I, 11. cylindrical channel II.

CONCRETE IMPLEMENTATION

[0030] The application will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0031] The application provides a spherical segment multi-hole foam ribbed panel cooling structure applied to a turbine blade, as shown in Figure 1-1 and Figure 1-2 , which comprises a plurality of cooling units, and a plurality of cooling units are connected in series in any direction around one cooling unit as needed to form a spherical segment multi-hole foam ribbed panel cooling structure.

[0032] As shown in Figure 2-1 and Figure 2-2 , one cooling unit specifically comprises:

[0033] An impact hole plate 2 and a film hole plate 6 are arranged in parallel and at intervals, both of which are quadrilateral plate structures, and impact channels 3 are formed at the intervals;

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

[0035] Four film hole channels 7, which are 1 / 4 cylindrical holes, are arranged at the four vertices of the film hole plate 6; the film hole 5 appears as four 1 / 4 cylindrical holes in one cooling unit, and when a plurality of cooling units are combined, the four 1 / 4 cylindrical holes are combined to form a complete film hole 5.

[0036] Four spoiler columns 4 are connected and arranged between the impact hole plate 2 and the film hole plate 6, and are arranged uniformly around the four sides of the impact hole 1;

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

[0038] As shown in Figure 3-1 and Figure 3-2As shown, the spoiler column 4 is a spherical hollow porous foam rib, which is formed by a plurality of porous unit cell arrays into a columnar structure, and each porous unit cell is processed in the following manner: the six faces and eight vertices of the unit cell cube are all spherical hollow treated by a sphere, the spherical grooves I8 on the six faces are all provided with a cylindrical passage I10 towards the center of the cube, and the six cylindrical passages I10 are in communication with each other; the spherical grooves II9 on the eight vertices are all provided with a cylindrical passage II11, and the cylindrical passage II11 is in communication with the cylindrical passage I10 and forms a complex internal channel network; the spherical hollow treatment and the internal cylindrical passage can effectively disperse the pressure generated in the fluid flow process, thereby reducing the overall fluid resistance, and can increase the contact area of the fluid and the surface of the spoiler column, thereby improving the heat exchange efficiency.

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

[0040] In some embodiments, the radius of each spherical groove I8 is the same, the radius of each spherical groove II9 is the same, the radius of the six cylindrical passages I10 is the same, and the radius of each cylindrical passage II is the same. This arrangement can form a uniform open porous structure, can simplify the manufacturing process, and can adapt to various manufacturing techniques. In computer simulation and analysis, consistent design parameters make the optimization process simpler, and the optimal design scheme can be found more easily.

[0041] In some embodiments, the impact hole 1 and the film hole 5 are both cylindrical holes with a hole diameter d, and are arranged in a direction perpendicular to the direction of the main flow gas. The relative distance between adjacent impact holes 1 along the flow direction and the spanwise direction is 6d, and the relative distance between adjacent film holes 5 along the flow direction and the spanwise direction is also 6d.

[0042] In some embodiments, the staggered distance between the film hole 5 and the impact hole 1 is 3d, the thickness of the impact hole plate 2 and the film hole plate 6 is 0.5-3d, and the height of the impact passage 3 is 0.5-3d.

[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 passage 3 is 0.25-1.

[0044] In the present application, the cooling airflow passes through the impact orifice plate 2, blows out from the impact orifice 1 into the double-wall impact channel 3 to impact the target surface for heat exchange, and then forms a wall jet around. The turbulence column 4 plays a role in strengthening the disturbance and increasing the specific surface area of the cooling airflow, thereby strengthening the heat exchange. Due to the structural characteristics of the porous turbulence column, although the cooling structure flow resistance increases, the pressure loss of the cooling airflow increases, but the flow loss of the cooling airflow can be accepted while the heat exchange effect is greatly enhanced. Then the cooling airflow enters the film hole 5 for convective heat exchange, and finally is sprayed to the outer wall of the film hole plate 6 to form a gas film, preventing the ablation of the gas film hole plate by high-temperature gas.

[0045] Embodiment

[0046] The ball-shaped porous foam ribbed panel cooling structure of the present application applied to a turbine blade is applied to the chord region of an aero-engine gas turbine blade. It is composed of an impact orifice 1, an impact orifice plate 2, a double-wall impact channel 3, a uniformly perforated porous turbulence column 4, a film hole 5 and a film hole plate 6. The impact orifice plate 2 is an inlet plate, close to the cold gas side, and a plurality of impact orifices perpendicular to the main flow direction are uniformly and equidistantly arranged on the plate, the impact orifice diameter d is 10 mm, and the relative distance between the impact orifices along the flow direction and the spanwise direction is 6d; the film hole plate is an outlet plate, close to the gas side, and a plurality of film holes perpendicular to the main flow direction are arranged on the plate, the film hole diameter is also d, the relative distance between the film holes along the flow direction and the spanwise direction is 6d, and the film holes and the impact orifices are arranged alternately with a spacing of 3d, the thickness of the impact orifice plate and the film hole plate is 1d; the impact distance, that is, the ratio of the distance between the impact orifice and the impact target surface to the impact orifice diameter d, is 1. The impact orifice and the film hole are both cylindrical holes. Four film hole channels are 1 / 4 of a film hole, and four film hole channels, four turbulence columns and one impact orifice form a basic cooling unit. The turbulence column is arranged in the cooling channel formed by the film hole plate and the impact orifice plate, and the relative position is located around the film hole, the relative distance of the turbulence column along the flow direction and the spanwise direction is 3d, and the turbulence column is arranged alternately with the film hole and the impact orifice; the spanwise width of the film hole plate and the impact orifice plate is 6d, the shape of the turbulence column is cylindrical, and the ratio of the height of the turbulence column to the height of the impact channel is 1.

[0047] In this embodiment, for the porous medium region, a modeling method based on representative element volume (REV) porous medium is used 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 effects of natural convection, radiation heat transfer and contact resistance between the porous medium turbulence element and the wall are ignored. The uniformly perforated turbulence column is formed by an array of unit cell crystals, and the pores are connected by cylindrical open channels. The porosity is changed by changing the radius of the cylinder and the distance between the centers 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 radius and center distance of the adjacent spheres. In this embodiment, the viscous loss coefficient is consistent with the inertial 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 the ideal gas air, and the fluid thermal conductivity λ f Assigned by linear interpolation, the solid plate material is steel, the solid thermal conductivity λ s It is 16.27w / (m·K).

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

[0050] like Figure 5 As shown in the comparison chart 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 inner and outer wall temperatures of the film orifice plates, the average inner and outer wall temperatures of the three solutions, Porous0.7, Porous0.8, and Porous0.9, are all lower than those of the existing SFP and Solid solutions. The uniform temperature distribution and efficient heat conduction path ensure a more uniform wall temperature, preventing local overheating. This demonstrates that the spherical segment porous foam rib plate cooling structure for turbine blades provided improved 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 groups of schemes, Porous0.7, Porous0.8 and Porous0.9, is 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-turbine structure and traditional spoiler columns.

[0053] In summary, the results show that the application of the spherical segment porous foam ribbed panel cooling structure to the turbine blade is a high-efficiency and reliable cooling scheme, which is suitable for occasions requiring high-performance cooling, such as aerospace engines, high-temperature industrial equipment, etc. Further increasing the effective heat exchange area of the target plate of the disturbance element brings heat exchange benefits, and at the same time, without increasing the cold gas flow, a cooling structure with excellent heat exchange characteristics and low flow resistance coefficient is designed, which is of great significance to the safe and stable operation of the blade.

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

[0055] At the same time, the disturbance column shape of the spherical segment porous foam rib structure is formed by additive manufacturing, which has a low density and a high specific strength, so the disturbance 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 the turbine blades of an aero-engine. The application of uniform open porous disturbance columns to the blades of an aero-engine can achieve lightweight design, improve strength and durability, and improve thermal conductivity, etc.

[0056] In addition, after the porous foam rib is arranged on the wall surface of the impingement target plate, the heat transfer performance of the low heat transfer area between adjacent impingement holes on the impingement target plate in the traditional impingement cooling is improved, thereby improving the heat transfer uniformity of the wall surface of the impingement target plate. Therefore, without increasing the cold gas flow, by reasonably adjusting the porosity, hole density, rib height, etc. of the porous foam rib, the impingement convection heat exchange inside the reinforced panel structure and the heat conduction of the local high-temperature area of the gas film plate are strengthened, thereby fully improving the cooling performance of the porous foam rib panel 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 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 provided 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 the four vertices of the air film hole plate (6); Four spoiler columns (4) are connected and arranged between the impact hole plate (2) and the air film hole plate (6), and are evenly arranged around the four sides of 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. 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. The spherical segment porous foam rib plate cooling structure for turbine blades according to 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 segment porous foam rib plate cooling structure for turbine blades according to 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 direction of the mainstream gas. 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. The spherical segment porous foam rib plate cooling structure for turbine blades according to 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 segment porous foam rib plate cooling structure for turbine blades according to 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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