A wave-shaped installation gap structure suitable for the end wall of a turbine guide vane

Abstract

This invention provides a wavy mounting gap structure suitable for turbine guide vane endwalls. The endwall has a wavy line structure at the pressure side edge of the mounting gap, extending parallel to the corresponding suction side edge line of adjacent endwalls. Under the action of sealing the cold air, the sealing plate forms a wavy mounting gap groove with the corresponding edge surfaces of two adjacent turbine guide vane endwalls. The wavy line structure can block and guide the gas entrained into the wavy mounting gap groove. This wavy line structure can reduce the flow velocity of the gas within the groove, while simultaneously reducing or eliminating the degree of gas overflow near the throat of the blade passage, thereby reducing or eliminating the high convective heat transfer coefficient region after the gas overflow point near the throat of the original blade passage. The lower gas temperature within the groove results in lower temperatures at the pressure and suction side edges of the turbine guide vane endwall, preventing ablation at the endwall edges.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine endwall cooling technology, specifically relating to a wave-shaped installation gap structure suitable for turbine guide vane endwalls. Background Technology

[0002] The turbine is one of the core components of a gas turbine, and its performance directly affects the turbine's operating performance. To meet development needs, the overall performance of a gas turbine is typically improved by increasing the turbine inlet temperature. With the advancement of gas turbine technology, advanced gas turbines can reach inlet temperatures of up to 2400K. Furthermore, due to the development of low-pollution and low-emission combustion technologies, the temperature of the inlet gas near the turbine endwall is closer to the mainstream temperature. This results in higher surface temperatures and thermal stress on the turbine guide vane endwall, making it highly susceptible to thermal deformation and high-temperature ablation.

[0003] Currently, discrete orifice film cooling, supplemented by upstream slot flow, is commonly used to reduce the surface temperature of the turbine guide vane endwall, ensuring its safe and reliable operation over extended periods under the complex and variable operating conditions of gas turbines. To minimize thermal deformation damage to the turbine guide vane endwall structure, turbine guide vanes typically employ a split design, maintaining installation margins between adjacent endwalls. This design results in installation gaps between the turbine guide vane endwalls. These gaps can easily lead to mainstream combustion gas intrusion and also affect the film coverage on the endwall surface.

[0004] In the papers "The Influence of Endwall Channel Gap on Endwall Leakage Flow Cooling" (Propulsion Technology, 2017, Vol. 38, No. 4, pp. 719-725), "Study on the Influence of Film Ore Arrangement on Turbine Endwall Cooling and Aerodynamic Performance" (Journal of Xi'an Jiaotong University, 2023, Vol. 57, No. 8, pp. 22-33), and "Experimental Study on the Influence of Assembly Gap Leakage Flow on Turbine Endwall Cooling" (Journal of Xi'an Jiaotong University, 2023, Vol. 57, No. 5, pp. 1-10), the authors proposed introducing sealing cold air into the installation gap to prevent the intrusion of mainstream high-temperature combustion gas and simultaneously achieve cooling of the downstream endwall surface. However, with the development of gas turbines, simply using sealing cold air cannot meet the sealing requirements under the complex and variable operating conditions of gas turbines. Currently, most of the sealing structures used are the sealing plates employed in "Numerical Simulation Study on Aerodynamic Characteristics of Turbine Guide Blade Endwall Installation Gap Leakage Flow" (Propulsion Technology, 2024, Vol. 45, No. 10, 2312089). The installation gap between the sealing plate structure and the end wall creates a groove. Some cold air and high-temperature combustion gas are entrained into this groove, flowing rapidly along its direction and prone to overflow at the throat of the blade passage. Under the influence of crossflow on the turbine guide vane end wall surface, the overflowing gas covers the suction side of the end wall. This overflow disrupts the development of the local boundary layer, causing it to redevelop downstream of the overflow point, resulting in a high convective heat transfer coefficient and making the area near the overflow point highly susceptible to ablation. Summary of the Invention

[0005] The purpose of this invention is to solve the problem in the prior art that the gas temperature in the mounting gap groove of the turbine guide vane end wall is too high, which leads to the high convection heat transfer zone generated after overflow near the throat of the blade passage, causing ablation of the suction side edge of the end wall. The invention provides a wave-shaped mounting gap structure suitable for the end wall of the turbine guide vane.

[0006] To achieve the above objectives, the technical solution provided by this invention is:

[0007] A wave-shaped mounting gap structure suitable for turbine guide vane endwalls is provided, wherein a mounting gap exists between two adjacent turbine guide vane endwalls, and a sealing strip is installed in the mounting gap to prevent the combustion gas in the vane passage from entering the cooling chamber. Its special feature is that:

[0008] The turbine guide end wall has a wavy line structure on the pressure side edge at the installation gap. The wavy line structure extends parallel to the corresponding suction side edge line of the adjacent turbine guide end wall. Under the action of sealing the cold air, the sealing sheet forms a wavy line-shaped installation gap groove with the corresponding edge surfaces of the two adjacent turbine guide end walls. The wavy line structure can block and guide the gas entrained in the wavy line-shaped installation gap groove.

[0009] Furthermore, the groove width D of the wavy mounting gap groove is 0.5-1.5mm, and the groove depth δ is 0.5D-2D.

[0010] Furthermore, the crest curvature radius r1 and trough curvature radius r2 of the wavy line structure may be equal or unequal.

[0011] Furthermore, the crest curvature radius r1 and trough curvature radius r2 of the wavy line structure are 1-4 mm.

[0012] Furthermore, the ratio of wavelength p to radius of curvature of the wavy line structure is between 1 and 4.

[0013] The advantages of the present invention are:

[0014] 1. The present invention relates to a wavy mounting gap structure applicable to the end wall of a turbine guide vane. At the mounting gap, the pressure surface edge of the turbine guide vane end wall is machined into a wavy shape. Under the action of sealing cold air, the sealing plate and the edges of the two turbine guide vane end walls form a novel wavy mounting gap groove. This wavy structure can reduce the flow velocity of the gas within the groove, while simultaneously reducing or eliminating the degree of gas overflow near the throat of the blade passage, thereby reducing or eliminating the high convective heat transfer coefficient region after the gas overflow point near the throat of the original blade passage.

[0015] 2. The gas temperature inside the structure is low, which keeps the temperature of the pressure side edge and suction side edge of the turbine guide wall low, thus avoiding the occurrence of ablation at the edge of the end wall.

[0016] 3. When the cold air jet from the air film hole on the pressure side of the end wall passes through the groove, the mainstream in the groove has a binding and acceleration effect on the cold air passing through the groove, which can improve the cooling effect of the downstream overflow point and the end wall surface of the blade passage outlet, and avoid the occurrence of ablation at this point. Attached Figure Description

[0017] The above and / or other features and advantages of the present invention will become more readily understood from the following description with reference to the accompanying drawings, which are not drawn to scale and some features are enlarged or reduced to show details of specific parts.

[0018] Figure 1 This is an axonometric view of the wave-shaped mounting gap structure applicable to the end wall of a turbine guide vane according to the present invention;

[0019] Figure 2 yes Figure 1 An enlarged view of region A in the middle shows the installation structure of the sealing strip;

[0020] Figure 3 This is a top view of the wave-shaped mounting gap structure applicable to the end wall of a turbine guide vane according to the present invention;

[0021] Figure 4 yes Figure 3 An enlarged view of region B shows the wavy line structure at the installation gap;

[0022] Figure 5 This is a side view of the wave-shaped mounting gap structure of the present invention applicable to the end wall of a turbine guide;

[0023] Figure 6 This is a schematic diagram of the working of the wave-shaped mounting gap structure applicable to the end wall of a turbine guide vane according to the present invention;

[0024] Figure 7 The comparison shows the distribution of air film cooling efficiency in the region near the overflow point between the installation gap structure of the present invention and the existing structure. (a) is the existing structure, and (b) is the structure of the present invention.

[0025] Figure 8 This is a comparison of the spanwise average film cooling efficiency of the mounting gap structure of the present invention with that of the existing structure.

[0026] Figure 9 The diagram shows a comparison of the convective heat transfer coefficient distribution in the region near the overflow point between the installation gap structure of the present invention and the existing structure. (a) is the existing structure, and (b) is the structure of the present invention.

[0027] In the diagram: 1- Turbine guide vane end wall; 2- Guide vane blade; 3- Film gas hole; 4- Sealing plate mounting groove; 5- End wall pressure side; 6- End wall suction side; 7- Sealing plate; 8- Sealed cold air inlet. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments thereof. It should be noted that the following detailed description of the present invention is for illustrative purposes only and is not intended to limit the scope of the invention.

[0029] It should be noted that, in the context of this invention, the terms “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” and “counterclockwise,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0030] Furthermore, terms such as "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0031] This invention addresses the problem that the design of the cooling structure on the end wall surface of a turbine guide vane did not fully consider the influence of the installation gap structure and the gas flow state within the installation gap groove on the heat transfer characteristics of the end wall surface, resulting in high-temperature ablation at the edge of the turbine guide vane end wall. The invention provides a wave-shaped installation gap structure suitable for turbine guide vane end walls. This structure is formed by machining the pressure side edge of a single / multi-unit turbine guide vane end wall structure into a wave-shaped structure while retaining the suction side structure of the turbine end wall unchanged. This effectively reduces the gas temperature within the installation gap groove of the end wall.

[0032] Reference Figures 1 to 6 The turbine guide vane includes one or more guide vanes 2, which are disposed on the turbine guide vane end wall 1. For example, each turbine guide vane end wall 1 has one guide vane, and multiple film perforations 3 are arranged on the surface of the turbine guide vane end wall 1. An installation gap exists between two adjacent turbine guide vane end walls 1. A sealing plate mounting groove 4 is formed at the installation gap between adjacent turbine guide vane end walls 1. A sealing plate 7 is placed in the sealing plate mounting groove 4 to prevent the combustion gas in the blade passage from entering the cold air chamber. After the sealing cold air enters the sealing plate mounting groove 4 from the sealing cold air inlet 8, it forces the sealing plate 7 in the sealing plate mounting groove 4 to move towards the outer surface of the end wall, thereby contacting the edge surface of the end wall pressure side 5 and the edge surface of the end wall suction side 6 of the turbine guide vane end wall. The sealing plate 7 forms an installation gap groove with the pressure side 5 and the suction side 6 of the turbine guide vane end wall.

[0033] In the wavy mounting gap structure applicable to the end wall of a turbine guide as an exemplary embodiment of the present invention, the end wall of the turbine guide has a wavy line structure on the pressure side edge at the mounting gap. The wavy line structure extends parallel to the corresponding suction side edge line of the adjacent turbine guide end wall. As a result, the sealing sheet 7 forms a novel wavy line mounting gap groove with the corresponding edge surfaces of the two adjacent turbine guide end walls under the action of sealing the cold air. The wavy line structure can block and guide the gas entrained in the wavy line mounting gap groove.

[0034] Specifically, the incoming mainstream flow and the outflow of cold air from the endwall film gas holes 3 are drawn into the wavy mounting gap groove, and then move downstream along the groove extension direction. The wavy structure on the endwall pressure side 5 obstructs and guides the gas in the groove, thereby reducing the flow velocity of the fluid in the groove. At the same time, it weakens or eliminates the overflow of cold air from the groove to the turbine endwall suction side 6 to a certain extent, thereby reducing or eliminating the high convective heat transfer coefficient zone after the gas overflow point near the throat of the original structure blade passage. The wavy mounting gap structure weakens the flow velocity of cold air in the groove, resulting in a larger amount of cold air accumulating in the groove and a lower gas temperature in the groove. This results in lower temperatures on the turbine guide vane edge endwall pressure side 5 and endwall suction side 6, thus preventing ablation at this location. In addition, when the cold air jet from the air film hole on the pressure side surface of the end wall passes through the groove, the mainstream in the groove has a binding and acceleration effect on the cold air passing through the groove, which can improve the air film coverage effect on the suction side surface 6 of the end wall of the overflow point downstream and the blade channel outlet, thus avoiding the occurrence of ablation at this location.

[0035] In some embodiments of the present invention, such as Figure 6 As shown, in order to prevent the turbine guide wall from jamming due to thermal expansion, the reserved installation gap is relatively small. If it is too large, it may lead to problems such as reduced aerodynamic efficiency. Therefore, the groove width D of the wavy installation gap groove, that is, the groove width at the crest and trough, can be designed to be in the range of 0.5-1.5mm, and the groove depth δ is 0.5D-2D.

[0036] According to the present invention, such as Figure 4 As shown, the crest curvature radius r1 and trough curvature radius r2 of the wavy line structure may be equal or unequal, but are preferably equal. Furthermore, the crest curvature radius r1 and trough curvature radius r2 of the wavy line structure are 1-4 mm. In a specific embodiment, the ratio of the wavelength p to the curvature radius of the wavy line structure is between 1 and 4.

[0037] The numerical simulation results of the wave-shaped mounting gap structure suitable for the end wall of a turbine guide vane, provided by the present invention, will be explained below with examples.

[0038] In this example, CFD software was used to calculate the film cooling characteristics of the turbine guide endwall surface cooling structure using both the existing structure (where the pressure and suction sides of adjacent turbine guide endwalls are straight edges) and the wave-shaped mounting gap structure of this invention. The structural parameters and calculation boundary conditions of the existing structure and the wave-shaped mounting gap of this invention are shown in Tables 1 and 2, respectively. The existing structure has a groove width D of 1 mm at the crest, and the wave-shaped mounting gap structure has a groove depth δ of 2 mm. The wave-shaped mounting gap structure has a groove width of 1.5 mm at the trough. The radii of curvature r1 and r2 at the crest and trough of the wave-shaped mounting gap structure are 2 mm, and the wavelength p is 5 mm. During the calculation, both the main inlet and the cold air inlet are pressure inlets, with a main inlet pressure of 9.50 bar and a temperature of 1569 K, and a cold air inlet pressure of 9.68 bar and a temperature of 669 K. The main outlet is a pressure outlet with a pressure of 5.91 bar.

[0039] Table 1

[0040]

[0041] Table 2

[0042]

[0043] When analyzing the calculation results, the focus is on the film cooling coverage in the area near the fluid overflow point within the groove, and the spanwise mean is calculated, as follows: Figure 7 and Figure 8 As shown, where Figure 8 In the diagram, the red line represents the existing structure, and the black line represents the structure of the present invention. Combining the film cooling efficiency distribution cloud map and the wall's limiting streamline distribution, it can be observed that when the cooling jet from the film cooling hole on the pressure side of the end wall flows through the mounting gap groove, a portion of the cold air directly crosses the mounting groove to cool the area above the overflow point on the other side of the end wall; the remaining cold air moves downstream under the influence of the fluid within the groove, cooling the area downstream of the overflow point. Compared to the existing structure, the wavy mounting gap groove structure of the present invention improves the film cooling effect on the end wall edge near the overflow point and the area downstream of the overflow point, while also reducing the area of ​​the uncooled high-temperature zone on the end wall surface in this region.

[0044] To further highlight the advantages of the wavy mounting gap groove structure, the convective heat transfer coefficient distribution on the end wall surface of the turbine guide vane using the existing structure and the wavy mounting gap structure of this invention was compared. During the calculation, the boundary conditions at the main inlet and outlet remained unchanged, and the end wall surface and mounting gap surface were constant-temperature walls with a wall temperature of 3000K. The calculation results are as follows: Figure 9As shown in the figure, the wavy mounting gap groove of the present invention significantly reduces the area of ​​the high convective heat transfer zone near the overflow point caused by fluid overflow within the groove, while also reducing the convective heat transfer coefficient of the surface of the fluid overflow area within the groove. Under these combined effects, the mounting gap structure proposed in this invention reduces the risk of high-temperature ablation at the edge of the turbine guide vane end wall, thus contributing to its long-term safe and stable operation.

[0045] Finally, it should be noted that the features mentioned and / or shown in the above description of exemplary embodiments of the present invention can be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. These combined or substituted technical solutions should also be considered to be included within the scope of protection of the present invention.

Claims

1. A wave-shaped mounting gap structure suitable for turbine guide vane endwalls, wherein a mounting gap exists between two adjacent turbine guide vane endwalls, and a sealing plate is provided in the mounting gap to prevent combustion gas in the blade passage from entering the cooling chamber, characterized in that: The turbine guide end wall has a wavy line structure on the pressure side edge at the installation gap. The wavy line structure extends parallel to the corresponding suction side edge line of the adjacent turbine guide end wall. Under the action of sealing the cold air, the sealing sheet forms a wavy line-shaped installation gap groove with the corresponding edge surfaces of the two adjacent turbine guide end walls. The wavy line structure can block and guide the gas entrained in the wavy line-shaped installation gap groove.

2. The wave-shaped mounting gap structure suitable for the end wall of a turbine guide vane according to claim 1, characterized in that: The groove width D of the wavy mounting gap groove is 0.5-1.5mm, and the groove depth δ is 0.5D-2D.

3. The wave-shaped mounting gap structure suitable for the end wall of a turbine guide vane according to claim 1 or 2, characterized in that: The crest curvature radius r1 and trough curvature radius r2 of the wavy line structure are either equal or unequal.

4. The wave-shaped mounting gap structure suitable for the end wall of a turbine guide vane according to claim 3, characterized in that: The crest curvature radius r1 and trough curvature radius r2 of the wavy line structure are 1-4 mm.

5. The wave-shaped mounting gap structure suitable for the end wall of a turbine guide vane according to claim 3, characterized in that: The ratio of the wavelength p to the radius of curvature of the wavy line structure is between 1 and 4.

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