Honeycomb type cooling laminate

Abstract

The invention discloses a honeycomb type cooling laminate which mainly comprises an inner layer wall, connecting ribs and an outer layer wall, impact holes are formed in the inner layer wall, the connecting ribs form a honeycomb-shaped impact cavity, and air film holes are formed in the outer layer wall. Cooling air enters the impact cavity through the impact holes, is evenly dispersed after impact cooling is completed on the inner wall face of the outer layer wall, and flows out through the air film holes in the outer layer wall, and an air film is formed to protect the outer layer wall. The space between the laminates is divided into the relatively closed honeycomb type impact cavities, so that the internal cooling area is increased, transverse flow interference and cold air retention between new and old cold air are avoided, the flow resistance is reduced, the cold air cooling potential is fully explored, the laminate cooling effect is remarkably improved, and the honeycomb type impact cavity has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine blades, and in particular to a honeycomb cooling layer plate. Background Art

[0002] Gas turbines are a representative product of the high-end equipment manufacturing industry, and the design of their hot-end components is a key technical area. Turbine blades, the core hot-end components that achieve heat-to-power conversion in gas turbines, operate in ultra-high-temperature environments. The turbine inlet temperature of current mainstream heavy-duty gas turbines exceeds the melting point of the blade substrate material, necessitating the deployment of efficient and precise cooling structures to achieve the design goals of reducing blade temperatures and extending blade life.

[0003] Traditional cooling methods for turbine blades mainly include impingement cooling, rib turbulence, film cooling, and layer cooling. Layer cooling is a cooling method with strong cooling capacity that combines impingement cooling, rib turbulence, and film cooling in the form of double walls. It is generally used in locations such as the leading edge and end wall of blades where the heat load is higher.

[0004] Plate cooling typically uses a simple cylindrical flow-distribution structure connecting the inner and outer walls to form an impingement cavity. Cooling air typically enters the impingement cavity through impingement holes in the inner wall. After impingement cooling, it exits the plate through film holes, forming an air film on the outer wall to protect the plate surface from direct heating by the high-temperature combustion gas. In practical applications, the pressure field outside the film hole outlet is significantly non-uniform, while the impingement cavity space is interconnected. This makes flow distribution design difficult and prone to uneven flow distribution of cooling air through the film holes. Cooling air inside the film holes, which are difficult to exit, can accumulate and form a crossflow toward the film holes, which are easy to exit. This phenomenon severely weakens the cooling effect of the impingement jet along the way, a phenomenon known as cross-flow interference. In addition to cross-flow interference, another disadvantage of traditional plate cooling structures is the limited effective cooling area. Due to the limitations of the investment casting process, the impingement holes, flow-distribution columns, and film holes are relatively simple cylindrical structures, and the cooling air can only exchange heat through forced convection between the holes, columns, and the plate surface. A considerable amount of cooling air is discharged from the plate without sufficient heat exchange. With the development of metal 3D printing technology, turbine blade plate cooling design can also explore more ingenious structures to avoid cross-flow interference and tap the heat exchange potential of cooling air. Summary of the Invention

[0005] In view of the above problems existing in the existing honeycomb cooling layer plate, the present invention is proposed.

[0006] Therefore, the present invention aims to provide a honeycomb cooling layer plate, which aims to avoid cross-flow interference and tap the heat exchange potential of cooling air.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: The honeycomb cooling laminated plate is integrally formed by 3D printing technology and includes an inner wall, an outer wall, and connecting ribs;

[0008] Among them, impact holes are provided on the inner wall, an impact cavity is formed between the connecting ribs, and film holes are provided on the outer wall;

[0009] The cross-sectional shape of the impact cavity includes a circle, a polygon, and a polygon with rounded corners.

[0010] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the diameter Di of the impact hole ranges from 0.5 to 5 mm.

[0011] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the diameter Df of the film hole ranges from 0.5 to 5 mm.

[0012] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the outer diameter Dc of the impact cavity ranges from 5 to 50 mm.

[0013] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the thickness Tr of the connecting rib ranges from 0.5 to 5 mm.

[0014] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the thickness Ti of the inner wall ranges from 0.1 to 10 mm.

[0015] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the height Tc of the impact cavity ranges from 0.1 to 10 mm.

[0016] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the thickness To of the outer wall ranges from 0.1 to 10 mm.

[0017] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the total thickness Tw of the cooling laminated plate ranges from 0.1 to 50 mm.

[0018] As a preferred solution of the honeycomb cooling laminated plate of the present invention, wherein: the pitch P of the cooling laminated plate ranges from 1 to 50 mm.

[0019] Advantages of the present invention: By arranging honeycomb-shaped connecting ribs, impact holes, and film holes inside the lamellar structure of the turbine blade, the impact chamber space is isolated, the cooling air jets are isolated from each other, the mutual interference between the new and old cooling air is avoided, the effective cooling area of the cold air is increased, the comprehensive cooling efficiency is increased by 39% compared with the existing technology of lamellar cooling, the effective cooling area is increased by 18%, and the total pressure loss coefficient is reduced by 16%. It can significantly enhance the cooling effect and the utilization rate of cooling air of the lamellar cooling structure of the turbine blade, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0021] Figure 1 It is a schematic diagram of the overall structure of the honeycomb cooling lamella of the present invention.

[0022] Figure 2 It is a schematic diagram of the cooling lamella structure of Comparative Example 1 of the present invention.

[0023] Figure 3 It is a top view of the honeycomb cooling lamella of the present invention and schematic diagrams of A-A and B-B cross-sections.

[0024] Figure 4(a) is a graph of the comprehensive cooling efficiency result of Embodiment 1 of the present invention;

[0025] Figure 4(b) is a graph of the comprehensive cooling efficiency result of Comparative Example 1 of the present invention;

[0026] Figure 4(c) is a schematic diagram of the comparison of the comprehensive cooling efficiency results. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will give a detailed description of the specific embodiments of the present invention with reference to the drawings of the specification.

[0028] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0029] Second, the so-called "one embodiment" or "embodiment" herein refers to specific features, structures, or characteristics that may be included in at least one implementation of the present invention. The phrase "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is separate or selectively exclusive of other embodiments.

[0030] Thirdly, the present invention is described in detail in conjunction with schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views showing the device structure are locally enlarged out of the general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0031] Embodiment 1

[0032] Referring to Figure 1 , which is the first embodiment of the present invention, a honeycomb cooling laminate is provided. This device is integrally formed by 3D printing technology and includes an inner wall, an outer wall, and connecting ribs;

[0033] Among them, impact holes are provided on the inner wall, an impact cavity is formed between the connecting ribs, and film holes are provided on the outer wall;

[0034] The cross-sectional shape of the impact cavity includes a circle, a polygon, and a polygon with rounded corners.

[0035] During use, the cold air impacts the target surface (the inner wall surface of the outer wall) in the form of a columnar jet through the impact holes. After the impact, it spreads out radially to form an attached-wall jet to wash and cool the target surface. The attached-wall jet and the cold air in the impact cavity exchange momentum through shear force to generate a secondary flow, and the secondary flow cools the inner wall and the connecting ribs. When the cold air reaches the film holes, it is sucked out of the impact cavity and forms a film on the outer wall surface of the outer layer to isolate the laminate from the high-temperature gas, thus completing the cooling process.

[0036] During operation, the diameter Di of the impact hole is set to 3 mm, the diameter Df of the film hole is set to 2 mm, the outer diameter Dc of the impact cavity is set to 28.62 mm, the thickness T of the connecting rib is set to 1 mm, the thickness Ti of the inner wall is set to 4 mm, the height Tc of the impact cavity is set to 4 mm, the thickness To of the outer wall is set to 3 mm, the total thickness Tw of the laminate structure is set to 11 mm, and the pitch P of the honeycomb laminate cooling structure is set to 25.79 mm.

[0037] Comparative Example 1

[0038] Referring to Figure 2, which is a comparative example of the present invention. This structure is a common design structure for laminated cooling. Refer to the public literature: Zhou WL, Deng QH, Feng ZP. Conjugate heat transfer analysis for laminated cooling effectiveness: Part A–effects of surface curvature[C]. ASME Paper GT2016-57243, 2016. (EI: 20164302940710)

[0039] During operation, the cold air passes through the impingement holes in the form of columnar jets to impinge on the target surface (the inner wall surface of the outer layer wall). After impingement, it is disrupted by the turbulators, forming a turbulent secondary flow to cool the turbulators and the inside of the laminated plate. After bypassing the turbulators, it leaves the laminated plate under the suction of the film holes and isolates the laminated plate from the high-temperature combustion gas in the form of a film on the outer wall surface of the outer laminated plate, completing the cooling process.

[0040] Perform numerical simulation on this comparative example, compare it with Example 1, and calculate the comprehensive cooling efficiency of the target surface and the total pressure loss coefficient under the condition of a cooling blowing ratio of 1.0 for the laminated plate (under the same flow rate condition). The blowing ratio is a dimensionless parameter used to measure the film outflow state of the film holes, and its definition is as follows:

[0041]

[0042] Where: ρ is the fluid density, with the unit of kg·m 3 ; u is the fluid velocity, with the unit of m / s; the subscript f represents the inlet position of the film hole; the subscript ∞ represents the oncoming flow position.

[0043] The comprehensive cooling efficiency is a dimensionless parameter used to measure the overall cooling performance of the internal and external cooling structures, and its definition is as follows:

[0044]

[0045] Where: is the total temperature at the mainstream inlet, with the unit of K; T w is the temperature of the outer surface of the wall, with the unit of K; is the total temperature at the cooling air inlet, with the unit of K.

[0046] The total pressure loss coefficient is a dimensionless parameter used to evaluate the flow loss of the cooling structure, and its definition is as follows:

[0047]

[0048] Where: is the mainstream flow rate, with the unit of kg / s; is the cooling air flow rate, with the unit of kg / s; is the total pressure of the outlet gas, with the unit of Pa; is the total pressure at the mainstream inlet, with the unit of Pa; is the total pressure at the cooling air inlet, with the unit of Pa. The comparison results of the comprehensive cooling effect are as Figure 3 shown.

[0049] The parameter values and common ranges used in the comparative calculation are listed in the following table (the ranges of some parameters that are strongly related to the simulation structure size, position, etc. or are dependent variables are not given) as shown in Table 1.

[0050]

[0051]

[0052] In the present invention, the honeycomb-shaped connecting ribs are used to replace the turbulators to undertake the role of connecting the inner and outer layer walls. Compared with the cooling area of the turbulators in the prior art, the cooling area of the honeycomb-shaped connecting ribs is larger, and it will not hinder the process of cold air flowing from the jet to the film holes. Therefore, the total pressure loss is lower. In addition, the unitized design also avoids the mutual interference of cold air in different impact holes. At the same time, arranging 6 film holes centered on the axis of the impact hole can uniformly suck cold air, so as to form an attached wall jet on the inner wall surface of the outer layer wall to wash the target surface to directly cool the outer layer wall. More film holes can also reduce the outflow velocity of the cold air, so that the cold air film adheres closely to the outer wall surface of the outer layer wall. Based on this, the cooling effects on both the inner and outer sides of the outer layer wall are improved.

[0053] The internal heat transfer amount is generally used to measure the cooling capacity of the internal cooling structure, but the external cooling performance will affect the heat entering the wall surface. Therefore, the isothermal wall boundary condition is adopted when calculating the internal heat transfer amount, that is, the internal cooling surface temperature is set to 1480K. The blowing ratio is used to measure the momentum strength of the film outflow. The higher the blowing ratio, the easier the film is to lose the cooling effect due to detaching from the wall surface. However, when the blowing ratio is too low, it indicates that the flow rate of the cold air in the film is low, which may lead to insufficient coverage effect. Generally, it is preferably about 0.5 - 1. The comprehensive cooling efficiency is used to measure the overall cooling performance. Therefore, the fluid-thermal coupling boundary condition is adopted when calculating, that is, the calculation domain includes both the fluid and solid parts, and the two are connected by a fluid-solid interface. The total pressure loss coefficient is a parameter to measure the flow losses of the internal and external cooling parts. Generally, it is desired that this value is as low as possible on the premise of meeting the cooling performance requirements. The blowing ratio and the total pressure loss coefficient are also calculated according to the fluid-thermal coupling boundary condition.

[0054] The data simulation calculation of the comprehensive cooling effect of Example 1 is carried out, and the results are shown in Table 2.

[0055] Table 2

[0056]

[0057] As can be seen from Table 2, the effective cooling area of Embodiment 1 of the present invention has increased by 18%, the internal heat exchange amount has increased by 24%, the blowing ratio has decreased by 0.5, the comprehensive cooling efficiency has increased by 39%, and the total pressure loss coefficient has decreased by 16%. This indicates that in internal cooling, Embodiment 1 improves the utilization rate of cold air by increasing the cooling area, avoids ineffective mixing through the honeycomb impingement cavity design, and improves the suction effect of cold air after impingement, thereby effectively reducing the flow loss; in external cooling, it improves the film coverage by reducing the blowing ratio and fully protects the outer wall surface. Therefore, the overall cooling performance of Embodiment 1 has been significantly improved, and the flow resistance has been effectively reduced, meeting the requirements of more efficient lamina cooling technology.

[0058] Importantly, it should be noted that the construction and arrangement of the present application shown in multiple different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who refer to this disclosure should easily understand that many modifications are possible without substantially departing from the novel teachings and advantages of the subject matter described in this application (for example, the dimensions, scales, structures, shapes and proportions of various elements, as well as parameter values (such as temperature, pressure, etc.), installation arrangements, use of materials, color, orientation changes, etc.). For example, an element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature, number or position of discrete elements can be changed or altered. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "means-plus-function" clause is intended to cover the structure that performs the recited function herein, and not only structural equivalents but also equivalent structures. Other substitutions, improvements, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the present invention is not limited to specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0059] In addition, in order to provide a concise description of the exemplary embodiments, not all features of the actual embodiments may be described (i.e., those features that are not relevant to the currently considered best mode of implementing the present invention, or those features that are not relevant to the implementation of the present invention).

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A honeycomb cooling laminated plate, characterized in that: The honeycomb cooling laminated plate is integrally formed by 3D printing technology and includes an inner wall, an outer wall and connecting ribs; Among them, impact holes are provided on the inner wall, impact cavities are formed between the connecting ribs, and film holes are provided on the outer wall; The cross-sectional shape of the impact cavity includes a circle, a polygon and a polygon with rounded corners.

2. The honeycomb cooling laminated plate according to claim 1, wherein: The diameter Di of the impact hole ranges from 0.5 to 5 mm.

3. The honeycomb cooling laminate according to claim 2, characterized in that: The diameter Df of the film hole ranges from 0.5 to 5 mm.

4. The honeycomb cooling laminated plate according to claim 3, wherein: The outer diameter Dc of the impact cavity ranges from 5 to 50 mm.

5. The honeycomb cooling laminated plate according to any one of claims 1 to 4, characterized in that: The thickness Tr of the connecting rib ranges from 0.5 to 5 mm.

6. The honeycomb cooling laminated plate according to claim 5, characterized in that: The thickness Ti of the inner wall ranges from 0.1 to 10 mm.

7. The honeycomb cooling laminated plate according to claim 6, wherein: The height Tc of the impact cavity ranges from 0.1 to 10 mm.

8. The honeycomb cooling laminated plate according to claim 7, wherein: The thickness To of the outer wall ranges from 0.1 to 10 mm.

9. The honeycomb cooling laminated plate according to claim 8, wherein: The total thickness Tw of the cooling laminated plate ranges from 0.1 to 50 mm.

10. The honeycomb cooling laminated plate according to claim 9, characterized in that: The pitch P of the cooling laminated plate ranges from 1 to 50 mm.

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