Gas turbine turbine hollow vane structure and cooling method thereof

Abstract

This invention discloses a hollow turbine stator structure and its cooling method for a gas turbine, comprising a blade, a core, and a base plate. The blade includes an upper edge plate, a lower edge plate, and a blade body disposed between the upper and lower edge plates. The upper and lower edge plates of the blade are machined with cooling film holes, and the blade body has a composite cooling structure. The core extends longitudinally through the blade, and its upper and lower ends are respectively installed and positioned with the upper and lower edge plates. The middle position is connected to the interior of the blade body. The core is machined with cooling air holes, which can form impact cooling on the inner surface of the blade cavity. The base plate is disposed on the lower surface of the lower edge plate, and a cooling gap is formed between the bottom outlet position of the core and the lower surface of the lower edge plate. The cooling scheme formed by the hollow turbine stator structure of this invention has three cooling paths, which can achieve all-round cooling of the blade.

Description

Technical Field

[0001] This invention relates to the field of gas turbine blade technology, and more specifically to a hollow stator blade structure for a gas turbine and its cooling method. Background Technology

[0002] With the continuous development of gas turbine technology, the performance of gas turbines has been gradually improved, and the corresponding turbine inlet temperature has also become higher and higher. At present, the turbine inlet temperature of gas turbines has exceeded the temperature resistance limit of equiaxed crystal high temperature alloys. In order to withstand the increasingly higher turbine inlet temperature, some gas turbines have begun to use directionally solidified high temperature alloys and single crystal high temperature alloys as blade materials. At the same time, the blades are internally cooled, and the temperature of the metal matrix of the blades is reduced to the temperature range that can be operated for a long time by cooling gas.

[0003] There are already various solutions for hollow cooling structures for turbine blades, applicable to working environments with different temperature levels and cooling requirements. This patent proposes a new hollow stator blade structure and cooling solution for gas turbines to meet the requirements of megawatt-class high-performance gas turbines. Summary of the Invention

[0004] This invention proposes a novel hollow turbine stator structure for gas turbines. This hollow stator structure is assembled and welded from three parts: a blade, a sheet metal insert, and a sheet metal base plate. The blade's inner cavity has a composite cooling structure, with cooling film perforations machined on the upper and lower edge plates, and cold air holes machined on the sheet metal insert, enabling impact cooling of the blade's inner surface. The blade assembly formed by the blade, sheet metal insert, and sheet metal base plate creates a complex internal cooling system. The cold air is divided into three paths to provide comprehensive cooling to the turbine stator, focusing on reducing the temperature of the high-temperature areas of the blade, enabling the blade to operate reliably for extended periods in high-temperature flue gas.

[0005] The technical solution of the present invention is as follows: A hollow stator structure for a gas turbine includes blades, inserts, and a base plate; The blade includes an upper edge plate, a lower edge plate, and a blade body disposed between the upper edge plate and the lower edge plate; the upper and lower edge plates of the blade are machined with cooling film holes, and the blade body has a composite cooling structure; The insert extends longitudinally through the blade, and its upper and lower ends are respectively installed and positioned with the upper edge plate and the lower edge plate; the middle position is connected to the inside of the blade body; the insert is machined with cooling air holes, which can form impact cooling on the inner surface of the blade. The base plate is disposed on the lower surface of the lower edge plate, forming a cooling gap between the bottom outlet position of the corresponding insert and the lower surface of the lower edge plate.

[0006] Furthermore, the upper edge plate is used for the installation and positioning of the blades, and has side sealing grooves A on both sides for installing sealing plates to seal the cooling gas and high-temperature flue gas. The upper edge plate is provided with cold air holes A, which penetrate from the upper surface of the upper edge plate to the lower surface of the upper edge plate. The upper edge plate is provided with an upper edge plate insert mounting edge for installing inserts and welding.

[0007] Furthermore, the blade is used to guide and accelerate airflow and forms a hollow inner cavity. Its inner surface is provided with flow direction baffles, which are attached to the outer surface of the insert to restrict the airflow between two adjacent flow direction baffles. There are oblique ribs between the flow direction baffles, and the height of the oblique ribs in the direction perpendicular to the outer surface of the insert is lower than that of the flow direction baffles to facilitate the flow of airflow. There are multiple rows of turbulence columns behind the flow direction baffles. The turbulence columns are spatially staggered to maximize the convective heat transfer coefficient of the cold air. There is an outlet baffle behind the turbulence columns to restrict the flow direction of the cold air and make it flow out from the cold air outlet slit at the tail of the blade.

[0008] Furthermore, the lower edge plate is used for the installation and positioning of the blades, and has side sealing grooves B on both sides for installing sealing plates to seal the high-temperature flue gas. The lower edge plate is machined with cold air holes B, which penetrate from the lower surface of the lower edge plate to the upper surface of the lower edge plate. The lower edge plate is provided with a lower edge plate insert mounting edge for installing inserts and welding.

[0009] Furthermore, the insert is formed by welding high-temperature alloy sheet metal. The outer surface of the insert body is in contact with the insert mounting edge of the upper edge plate of the blade, the flow direction baffle of the blade cavity, and the insert mounting edge of the lower edge plate of the blade. The insert is welded to the blade at the edges of the insert mounting edges of the upper edge plate and the insert mounting edges of the lower edge plate to form a whole. The insert has densely machined leading-edge cooling holes at the leading edge position in the direction of blade flow. The cold air directly impacts and cools the leading edge position of the inner surface of the blade through the leading-edge cooling holes, enhancing heat exchange and reducing the highest temperature position of the blade. Several side cooling holes are machined on both sides of the insert to cool the two sides of the inner surface of the blade. The leading-edge cooling holes and side cooling holes in the same row are located between the same flow direction baffles or between the flow direction baffles and the insert mounting edge, controlling the cold air flow distribution of each row of air.

[0010] Furthermore, the base plate is a high-temperature alloy sheet metal part, the shape of which fits the shape of the lower surface of the blade lower edge plate, and is integrated with the blade lower edge plate by welding; there is a gap between the base plate and the lower edge plate insert mounting edge, so that the cold air passes through the middle of the insert from the top of the blade to the bottom cavity, and then flows out from the cold air hole B of the lower edge plate.

[0011] A cooling method for a hollow stator structure of a gas turbine includes the following steps: The cooling air is divided into three channels to cool the turbine stator blades in all directions, enabling the blades to work reliably for a long time in high-temperature flue gas. The path of the first cold air: The cold air enters directly from the top of the blade into the cold air hole A of the upper edge plate, passes through the upper edge plate and enters the lower surface of the upper edge plate, where it mixes with the mainstream high-temperature flue gas. The cold air forms a gas film cooling on the local high-temperature area on the lower surface of the upper edge plate. The path of the second cooling air: The cooling air enters the cavity of the insert from the top of the blade. Part of it flows out from the cooling hole at the leading edge of the insert, which impacts and cools the leading edge of the blade cavity. Part of it flows out from the cooling hole on the side of the insert, which impacts and cools the inner surface of the blade cavity. After the cooling air converges, it flows through the turbulence column in the blade cavity. The blade temperature is reduced through convection heat transfer and heat conduction. Finally, it flows out from the channel formed by the outlet baffle of the blade cavity. It mixes with the mainstream high-temperature flue gas through the cold air outlet slit of the blade cavity, and cools the blade from front to back in all directions. The path of the third cold air: After passing through the insert cavity from the top of the blade, the cold air arrives at the cavity formed by the blade bottom plate and the blade lower edge plate, passes through the cold air hole B of the blade lower edge plate, mixes with the mainstream high-temperature flue gas, and the cold air forms a gas film cooling on the local high-temperature area on the upper surface of the lower edge plate.

[0012] The beneficial effects of this invention are as follows: 1) By using three components—blade, sheet metal insert, and sheet metal base plate—for welding, the complex hollow cooling structure of the blade can be achieved at a lower cost; ultimately, a solution is achieved where the cooling air is divided into three paths to provide all-round cooling for the blade. 2) The blade consists of an upper edge plate, a blade body, and a lower edge plate, which effectively isolates high-temperature flue gas and cold air, forming a flow channel for the gas turbine; after the sealing plate is installed in the side sealing groove of the blade edge plate, it forms a seal between the high-temperature flue gas and cold air, and the cold air hole is used to form a cooling flow path. The insert is installed and welded on the insert installation side. 3) The flow direction baffles inside the blade cavity fit snugly against the insert, restricting the flow direction of the cold air and enhancing the cooling effect; the oblique ribs inside the blade cavity are lower than the flow direction baffles, enhancing the cooling effect; the cross-arranged turbulence columns inside the blade cavity can enhance the cooling effect of the cooling air; the outlet baffles and cold air outlet slits inside the blade cavity guide the gas flow direction and merge into the main flow path. 4) The insert is formed by cutting and shaping high-temperature alloy sheet metal and then welding it, which can form a complex double-layer cooling structure; the densely distributed leading edge cooling holes of the insert enhance the impact heat transfer of the leading edge of the blade inner cavity, and the side cooling holes enhance the impact heat transfer of the two sides of the blade inner cavity; the cold air coming out of the same row of leading edge cooling holes and side cooling holes is restricted by the inner cavity to the baffle or insert mounting edge, which restricts the gas flow direction and thus enhances heat transfer. 5) The cooling scheme formed by the hollow stator blade structure of the turbine has three cooling paths, which can achieve all-round cooling of the blades. Attached Figure Description

[0013] Figure 1 This is a schematic diagram showing the installation of the blade, insert, and base plate of the present invention. Figure 2 This is a schematic diagram of the blade side structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the blade of the present invention; Figure 4 This is a three-dimensional structural diagram of the ferrule of the present invention; Figure 5 This is a schematic diagram of the cooling air hole structure on the upper edge plate of the present invention; Figure 6 This is a schematic diagram of the fitting structure between the insert and the blade of the present invention; Figure 7 This is a schematic diagram of the cooling air hole structure of the lower edge plate of the present invention; In the diagram: 1. Blade; 11. Upper edge plate; 111. Side sealing groove A; 112. Cooling air hole A; 113. Upper edge plate insert mounting edge; 12. Blade body; 121. Flow direction baffle; 122. Diagonal rib; 123. Turbid column; 124. Outlet baffle; 125. Cooling air outlet slit; 13. Lower edge plate; 131. Side sealing groove B; 132. Cooling air hole B; 133. Lower edge plate insert mounting edge; 2. Insert; 21. Insert body; 22. Leading edge cooling hole; 23. Side cooling hole; 3. Base plate; 41. Weld between the upper edge plate and the insert; 42. Weld between the lower edge plate and the insert; 43. Weld between the lower edge plate and the base plate. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] like Figure 1 As shown, the hollow turbine stator structure of the present invention consists of a blade 1, a core 2, and a base plate 3. The upper edge plate 11 of the blade 1 is connected to the core 2 by welding, the lower edge plate 13 of the blade 1 is connected to the core 2 by welding, and the lower edge plate 13 of the blade 1 is connected to the base plate 3 by welding.

[0016] Overall technological innovations: The method of welding the blade, sheet metal insert, and sheet metal base plate together can realize the complex hollow cooling structure of the blade at a lower cost. This avoids the need to directly achieve the structure by casting, which would increase the technical difficulty and reduce the blade's yield. The welding combination of the three components—blade, insert, and base plate—ultimately forms the cooling scheme protected by this invention, which is a scheme in which the cold air is divided into three paths to cool the blade in all directions.

[0017] Blade 1 is formed from a high-temperature alloy casting part through machining, which can form a complex internal cavity structure. Blade 1 consists of an upper edge plate 11, a blade body 12, and a lower edge plate 13. These three parts form the support structure and flow channel of the blade. The blade body 12 forms a hollow internal cavity to cool the inside of the blade. The upper edge plate 11 is used for the installation and positioning of the blade. Both sides of the upper edge plate have upper edge plate side sealing grooves 111 for installing sealing plates to seal the cooling gas and high-temperature flue gas. The upper edge plate 11 has a cooling air hole A112 that penetrates from the upper surface of the upper edge plate to the lower surface of the upper edge plate. The upper edge plate 11 has an upper edge plate insert mounting edge 113 for installing the insert 2 and welding it.

[0018] The lower edge plate 13 is used for the installation and positioning of the blades. Both sides of the lower edge plate have side sealing grooves 131 for installing sealing plates to seal the high-temperature flue gas. The lower edge plate 13 is machined with a cold air hole B132, which penetrates from the lower surface of the lower edge plate to the upper surface of the lower edge plate. The lower edge plate 13 is provided with a core mounting edge 133 for installing the core 2 and welding it.

[0019] Blade technology innovations: The upper and lower edge plates of the blades isolate the high-temperature flue gas from the cold air, while the blade body guides and accelerates the high-temperature flue gas, together forming the flow channel of the gas turbine, which impacts the downstream moving blades to do work. The side sealing grooves of the blade edge plates (upper and lower edge plates) are used to install sealing plates, which restrict the direct leakage of high-pressure cold air into the main flow path and allow it to flow only into the cooling holes and inserts of the blade edge plates. The cold air holes penetrate the edge plates, allowing the cold air to flow from the outside of the edge plates through the cold air holes into the main flow path. The insert mounting edge fits snugly against the insert to facilitate the installation of the insert and ensure the stability of the welding.

[0020] The blade 12 is used to guide and accelerate the airflow and forms a hollow inner cavity of the blade. Its inner surface is provided with flow direction baffles 121, which are attached to the outer surface of the insert 2 to restrict the airflow between two adjacent flow direction baffles. There are oblique ribs 122 between the flow direction baffles. The height of the oblique ribs is lower than that of the flow direction baffles to facilitate the flow of air. The multi-rib structure can increase the heat transfer area of ​​the inner surface of the blade and increase the convective heat transfer coefficient. There are multiple rows of turbulence columns 123 behind the flow direction baffles. The turbulence columns are spatially staggered to maximize the convective heat transfer coefficient of the cold air. There is an outlet baffle 124 behind the turbulence columns to restrict the flow direction of the cold air and make it flow out from the cold air outlet slit 125 at the tail of the blade.

[0021] Leaf blade technology innovations: The hollow and complex structure of the inner cavity of the blade is difficult to achieve directly through machining. Only by adopting a hollow structure can complex heat transfer forms such as impact heat transfer and convection heat transfer be formed inside the blade to reduce the temperature of the blade. In this invention, the blade is made by precision casting of high-temperature alloy blanks. Finally, only the mounting structure and cooling structure on the edge plate need to be machined. The flow direction baffle inside the blade is fitted with the insert core, which restricts the direction of the cold air flowing out from the cooling holes at the leading edge and side of the insert core, guides it to flow in the flow direction, reduces radial flow, and enhances the convective heat transfer effect of the cooling air. The oblique ribs inside the blade cavity are lower than the flow baffles, which facilitates the passage of gas. The arrangement of ribs can increase the heat exchange area of ​​the cooling gas and enhance the convective heat transfer coefficient, thereby enhancing the cooling effect. The staggered arrangement of the turbulence columns inside the blade cavity can enhance the convective heat transfer effect of the cooling air, and at the same time absorb the high temperature heat of the blade through heat conduction, thereby reducing the temperature of the blade. The outlet baffle inside the blade guides the flow direction of the gas, which flows into the main flow path through the cold gas outlet slit, maintaining the consistency of the flow direction of the cold gas and the high-temperature flue gas in the main flow path, and reducing gas flow loss.

[0022] The insert 2 is formed by welding high-temperature alloy sheet metal. The outer surface of the insert body 21 is in contact with the insert mounting edge 113 of the upper edge plate of the blade, the flow direction baffle 121 of the blade inner cavity, and the insert mounting edge 133 of the lower edge plate of the blade. The insert is welded to the blade at the edges of the insert mounting edges of the upper and lower edge plates to form an integral unit. The insert has densely machined leading edge cooling holes 22 at the leading edge position of the blade in the direction of incoming flow. The cold air directly impacts and cools the leading edge position of the inner surface of the blade through the leading edge cooling holes, enhancing heat transfer and reducing the highest temperature position of the blade. Several side cooling holes 23 are machined on both sides of the insert to cool the two sides of the inner surface of the blade. The leading edge cooling holes and side cooling holes in the same row are all located between the same flow direction baffles in the inner cavity or between the flow direction baffles in the inner cavity and the insert mounting edge, controlling the cold air flow distribution of each row of air.

[0023] Innovations in ferrule technology: It is difficult to achieve a double-layer cooling structure through casting. The insert is made of high-temperature alloy sheet metal, which is cut, stamped and shaped by mold, and finally welded into a complete insert, which is inserted into the inner cavity of the blade to form a complex double-layer cooling structure. The leading edge of the blade faces the high-temperature flue gas flow directly, where the temperature is the highest. The leading edge cooling holes of the insert have a high density, which can enhance the impact heat transfer of the inner cavity leading edge and has a high heat transfer coefficient. The side cooling holes conduct impact heat transfer on both sides of the inner cavity of the blade, and the heat transfer coefficient is smaller than that of the leading edge. The leading edge cooling holes and side cooling holes are arranged in the channel formed by the inner cavity flow direction baffle and insert mounting edge to restrict the flow direction of cold air and reduce the flow in the radial direction, thereby enhancing the convective heat transfer effect.

[0024] The base plate 3 is a high-temperature alloy sheet metal part, and its shape fits the lower surface of the blade's lower edge plate. It is welded to the blade's lower edge plate to form a whole. There is a gap between the base plate and the insert mounting edge of the lower edge plate, which allows the cool air to pass through the middle of the insert from the top of the blade to reach the bottom cavity, and then flow out from the cooling hole B of the lower edge plate.

[0025] Innovations in the base plate technology: By using a high-temperature alloy sheet metal cutting and shaping method, the shape of the base plate fits the shape of the lower edge plate. Only one ring of welding is needed around the base plate to weld the base plate and the lower edge plate into an integral structure. A gap is formed between the mounting edge of the base plate and the lower edge plate, and a cavity is formed between the base plate and the lower edge plate. Cold air can smoothly pass through the gap into the cavity and then enter the cold air hole B of the lower edge plate.

[0026] The turbine hollow stator blade structure of the present invention forms a turbine hollow stator blade cooling scheme, forming three cooling paths in the blade, which can cool the upper edge plate, blade body and lower edge plate of the blade in all directions.

[0027] like Figure 5 As shown, this is the path of the first cold air. The cold air enters directly from the top of the blade into the cold air hole A of the upper edge plate, passes through the upper edge plate, and enters the lower surface of the upper edge plate, where it mixes with the mainstream high-temperature flue gas. The cold air forms a gas film cooling effect on the local high-temperature area on the lower surface of the upper edge plate.

[0028] like Figure 6 As shown, this is the path of the second cooling gas. The cooling gas enters the cavity of the insert from the top of the blade. Part of it flows out from the cooling hole at the leading edge of the insert, impacting and cooling the leading edge of the blade cavity. Part of it flows out from the cooling hole on the side of the insert, impacting and cooling the inner surface of the blade cavity. After the cooling gas converges, it flows through the turbulence column in the blade cavity, reducing the blade temperature through convection and heat transfer. Finally, it flows out from the channel formed by the outlet baffle of the blade cavity, and mixes with the mainstream high-temperature flue gas through the cold gas outlet slit, providing all-round cooling of the blade from front to back.

[0029] like Figure 7 As shown, this is the path of the third cold air. After passing through the insert cavity from the top of the blade, part of the cold air reaches the cavity formed by the blade bottom plate and the blade lower edge plate. It passes through the cold air hole B on the blade lower edge plate and mixes with the mainstream high-temperature flue gas. The cold air forms a gas film cooling on the local high-temperature area on the upper surface of the lower edge plate.

[0030] The main high-temperature flue gas is the high-temperature and high-pressure gas produced by the combustion of high-pressure air in the combustion chamber of the gas turbine. It is the main medium used by the gas turbine to do work and is an essential working fluid in all gas turbines. The main high-temperature flue gas flows on the outer surface of the blades. Only cooling gas exists inside the blades, and the high-temperature flue gas does not enter any cavity inside the blades.

[0031] Technological innovation points: 1. A first cooling path is formed through the cooling air hole A on the upper edge plate, a second cooling path is formed through the structure of the insert and the inner cavity of the blade, and a third cooling path is formed through the cooling air hole B of the insert, the bottom plate and the lower edge plate. 2. Because a sealing plate is installed in the sealing groove on the side of the upper edge plate, the cooling air at the top of the blade is restricted to entering only the cooling air hole A of the upper edge plate and the cavity of the insert. The cooling air through the cooling air hole A of the upper edge plate enters the lower surface of the upper edge plate, and after forming a layer of cooling air film on the lower surface of the upper edge plate, it gradually mixes with the high temperature flue gas, reducing the convective heat transfer temperature in the local area of ​​the lower surface of the upper edge plate, forming a gas film cooling for the local high temperature area of ​​the lower surface of the upper edge plate, and lowering the temperature. This path of cooling air forms the first cooling path. 3. The cold air entering the cavity of the insert is restricted from flowing out through the cooling holes of the insert. The leading edge cooling holes have a high density, which focuses on impact cooling at the leading edge of the blade cavity, thereby reducing the temperature load of the stationary blade at the position with the highest temperature. The side cooling holes have a lower density than the leading edge cooling holes, which impact heat exchange on both sides of the blade cavity. After impact heat exchange, the cold air flows along the flow direction and converges at the trailing edge of the insert. After merging, it flows through the cross-arranged turbulence columns. A convective heat exchange structure is formed between the cold air and the turbulence columns. The heat of the blade part is carried away by heat conduction through multiple rows of turbulence columns. Finally, it flows out from the channel formed by the outlet baffle. After passing through the cold air outlet slit, it mixes with the high-temperature flue gas in the main flow channel. This path uses different cooling heat exchange methods at different positions in the blade cavity from the leading edge to the trailing edge, reducing the temperature of the blade part in all directions. This path of cold air forms the second cooling path. 4. A portion of the cold air entering the cavity in the middle of the insert enters the cavity formed by the bottom plate and the lower edge plate of the blade. It is restricted from flowing out through the cold air hole B of the lower edge plate. The cold air passing through the cold air hole B of the lower edge plate enters the upper surface of the lower edge plate. After forming a layer of cold air film on the upper surface of the lower edge plate, it gradually mixes with the high-temperature flue gas, reducing the convective heat transfer temperature of the local area on the upper surface of the lower edge plate. It forms a gas film cooling for the local high-temperature area on the upper surface of the lower edge plate, thus lowering the temperature. This path of cold air forms the third cooling path. Example

[0032] The blade blank is made using precision casting technology with no allowance. The cast blade includes an upper edge plate 11, a blade body 12, and a lower edge plate 13. The upper edge plate is cast with a core mounting edge 113. The inner cavity of the blade body is cast with a flow direction baffle 121, an oblique rib 122, a turbulence column 123, an outlet baffle 124, and a cold air outlet slit 125. The lower edge plate is cast with a core mounting edge 133. The upper and lower edge plates of the blade blank are machined, and the mounting positions are ground to ensure accuracy. Side sealing grooves A111 are machined on both sides of the upper edge plate. Cold air holes A112 are drilled in the upper edge plate, penetrating the upper and lower surfaces of the upper edge plate. Sealing grooves 131 are machined on both sides of the lower edge plate. Cold air holes B132 are drilled in the lower edge plate, penetrating the upper and lower surfaces of the lower edge plate.

[0033] The insert 2 is cut from thin-walled sheet metal, and after being molded, it is welded to form the insert body 21. A front cooling hole 22 is machined at the front edge of the insert, and a side cooling hole 23 is machined on both sides of the insert.

[0034] The base plate 3 is cut from thin-walled sheet metal and shaped by a mold to match the shape of the lower edge plate.

[0035] Insert the insert 2 into the inner cavity of the blade 1. The outer surface of the insert 2 is in contact with the insert mounting edge 113 of the upper edge plate of the blade, the flow direction baffle 121 of the inner cavity of the blade, and the insert mounting edge 133 of the lower edge plate of the blade. Full circumferential welding is performed at the insert mounting edge of the upper edge plate and at the insert mounting edge of the lower edge plate, so that the insert 2 and the blade 1 form a whole.

[0036] The base plate 3 is attached to the lower surface of the lower edge plate of the blade 1, and full-circumference welding is performed on the edge of the base plate 3 to make the base plate 3 and the blade 1 form a whole. This completes the structure of the hollow turbine stator.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Various equivalent substitutions or modifications made by those skilled in the art without departing from the spirit and substance of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hollow stator blade structure for a gas turbine, characterized in that, Includes blades (1), insert (2), and base plate (3); The blade (1) includes an upper edge plate (11), a lower edge plate (13), and a blade body (12) disposed between the upper edge plate (11) and the lower edge plate (13); the upper and lower edge plates of the blade (1) are machined with cooling air film holes, and the blade body has a composite cooling structure; The insert (2) runs longitudinally through the blade (1), and its upper and lower ends are respectively installed and positioned with the upper edge plate (11) and the lower edge plate (13); the middle position is connected to the inside of the blade body (12) of the blade (1); the insert (2) is machined with cold air holes, which can form impact cooling on the inner surface of the blade. The base plate (3) is disposed on the lower surface of the lower edge plate (13), forming a cooling gap between the bottom outlet position of the corresponding insert (2) and the lower surface of the lower edge plate (13).

2. The hollow stator blade structure for a gas turbine according to claim 1, characterized in that, The upper edge plate (11) is used for the installation and positioning of the blades. It has side sealing grooves A (111) on both sides for installing sealing plates to seal the cooling gas and high-temperature flue gas. The upper edge plate (11) is provided with cold air holes A (112). The cold air holes A (112) penetrate from the upper surface of the upper edge plate (11) to the lower surface of the upper edge plate (11). The upper edge plate (11) is provided with an upper edge plate insert mounting edge (113) for installing inserts (2) and welding them.

3. The hollow stator blade structure for a gas turbine according to claim 1, characterized in that, The blade (12) is used to guide and accelerate the airflow and form a hollow inner cavity of the blade. Its inner surface is provided with flow direction baffles (121). The flow direction baffles (121) are attached to the outer surface of the insert (2) to restrict the airflow between two adjacent flow direction baffles. The flow direction baffles (121) are provided with oblique ribs (122), and the height of the oblique ribs (122) in the direction perpendicular to the outer surface of the insert is lower than that of the flow direction baffles (121) to facilitate the flow of airflow. Multiple rows of turbulence columns (123) are provided behind the flow direction baffles (121). The turbulence columns (123) are spatially staggered to maximize the convective heat transfer coefficient of the cold air. An outlet baffle (124) is provided behind the turbulence columns (123) to restrict the flow direction of the cold air and make it flow out from the cold air outlet slit (125) at the tail of the blade.

4. The hollow stator blade structure for a gas turbine according to claim 1, characterized in that, The lower edge plate (13) is used for the installation and positioning of the blades. It has side sealing grooves B (131) on both sides for installing sealing plates to seal the high-temperature flue gas. The lower edge plate (13) is machined with cold air holes B (132). The cold air holes B (132) penetrate from the lower surface of the lower edge plate (13) to the upper surface of the lower edge plate (13). The lower edge plate (13) is provided with a lower edge plate insert mounting edge (133) for installing inserts (2) and welding them.

5. The hollow stator blade structure for a gas turbine according to claim 1, characterized in that, The insert (2) is formed by welding high-temperature alloy sheet metal. The outer surface of the insert body (21) is in contact with the insert mounting edge (113) of the upper edge plate of the blade, the flow direction baffle (121) of the blade inner cavity, and the insert mounting edge (133) of the lower edge plate of the blade. The insert is welded to the blade to form a whole at the edges of the insert mounting edge (113) of the upper edge plate and the insert mounting edge (133) of the lower edge plate. The insert (2) has densely processed leading edge cooling holes (22) at the leading edge position of the blade in the direction of the incoming flow. The cold air directly impacts and cools the leading edge position of the inner surface of the blade through the leading edge cooling holes (22), which enhances heat exchange and reduces the position with the highest blade temperature. The insert (2) has several side cooling holes (23) processed on both sides to cool the two sides of the inner surface of the blade. The leading edge cooling holes (22) and side cooling holes (23) in the same row are located between the same flow direction baffles (121) or between the flow direction baffles (121) and the insert mounting edge, which controls the distribution of cold air flow in each row of the air.

6. The hollow stator blade structure for a gas turbine according to claim 1, characterized in that, The base plate (3) is a high-temperature alloy sheet metal part, and its shape fits the shape of the lower edge plate (13) of the blade. It is welded to the lower edge plate (13) of the blade to form a whole. There is a gap between the base plate (3) and the mounting edge (133) of the lower edge plate insert, so that the cold air passes through the middle of the insert (2) from the top of the blade to reach the bottom cavity, and then flows out from the cold air hole B (132) of the lower edge plate.

7. A cooling method for a hollow stator structure of a gas turbine turbine according to any one of claims 1-6, characterized in that, The process includes the following: The cooling air is divided into three channels to cool the turbine stator blades in all directions, enabling the blades to work reliably for a long time in high-temperature flue gas. The path of the first cold air: The cold air enters directly from the top of the blade into the cold air hole A of the upper edge plate, passes through the upper edge plate and enters the lower surface of the upper edge plate, where it mixes with the mainstream high-temperature flue gas. The cold air forms a gas film cooling on the local high-temperature area on the lower surface of the upper edge plate. The path of the second cooling air: The cooling air enters the cavity of the insert from the top of the blade. Part of it flows out from the cooling hole at the leading edge of the insert, which impacts and cools the leading edge of the blade cavity. Part of it flows out from the cooling hole on the side of the insert, which impacts and cools the inner surface of the blade cavity. After the cooling air converges, it flows through the turbulence column in the blade cavity. The blade temperature is reduced through convection heat transfer and heat conduction. Finally, it flows out from the channel formed by the outlet baffle of the blade cavity. It mixes with the mainstream high-temperature flue gas through the cold air outlet slit of the blade cavity, and cools the blade from front to back in all directions. The path of the third cold air: After passing through the insert cavity from the top of the blade, the cold air arrives at the cavity formed by the blade bottom plate and the blade lower edge plate, passes through the cold air hole B of the blade lower edge plate, mixes with the mainstream high-temperature flue gas, and the cold air forms a gas film cooling on the local high-temperature area on the upper surface of the lower edge plate.

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