Heat pipe type cooling structure and method for tail edge of blade tip of turbine blade and blade

Abstract

The invention relates to the field of gas turbines, in particular to a heat pipe type cooling structure and method for a blade tip tail edge of a turbine blade and the blade, and the heat pipe type cooling structure comprises a heat pipe inserted in the blade tip tail edge, a tail edge crack formed in the blade tip tail edge and a blade tip tail edge internal cooling channel formed in the blade tip tail edge; the heat pipe cold end of the heat pipe extends into the cooling channel in the blade tip tail edge, and the heat pipe hot end of the heat pipe is embedded into the blade tip tail edge; the trailing edge crack is communicated with the blade tip trailing edge internal cooling channel; the phase change working medium in the heat pipe comprises sodium and potassium; according to the structure, centrifugal force of blade rotation is used as driving force to drive circular flow of a phase change working medium in the heat pipe and cooperate with an internal cooling channel and a trailing edge crack in the blade tip trailing edge to effectively cool the blade tip trailing edge, the cooling pertinence is high, the cooling efficiency is high, the structure can be suitable for transformation of different turbine blades, the transformation cost is low, and the application range is wide. The problem of ablation of the tail edge area of the turbine blade tip is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field, in particular to a heat pipe type cooling structure for a turbine blade tip trailing edge, a method and a blade. BACKGROUND

[0002] Turbine blades are the "heart components" of aero-engines and heavy-duty gas turbines, and their performance directly determines the thrust-to-weight ratio, thermal efficiency and reliability of the power system. With the continuous improvement of the thrust demand of aero-engines and the efficiency of gas turbine combined cycles, the turbine inlet gas temperature has climbed to 1800-2000K. When the turbine blade is working, it is often in an extreme thermal environment, which causes the turbine blade to bear the coupling effect of thermal stress, centrifugal stress and aerodynamic load. Among them, the tip trailing edge region becomes the most concentrated part of the thermal load due to its special geometry, and long-term operation can easily cause failure modes such as high-temperature ablation and thermal fatigue cracks, which seriously threaten the safety and life of the engine. Therefore, developing high-efficiency cooling technology to control the temperature of the tip trailing edge has become a key technical bottleneck in the field of aviation power.

[0003] The existing way to deal with the high temperature challenge of the tip trailing edge region is to arrange various internal and external air cooling structures on the hollow blade to cool the blade. However, whether it is external cooling or internal cooling, the current air cooling scheme does not have a good solution, because there are complex leakage vortex, passage vortex and other flow field structures in the tip region, which causes the cooling air to be easily blown away from the wall by the high-temperature gas, making it difficult to cover and protect the tip trailing edge in a wide working range; inside, due to the thinness of the tip trailing edge, the space is narrow and there is not enough space to arrange efficient internal cooling measures. In summary, the tip trailing edge, this high-temperature region, has always been a difficulty in cooling.

[0004] Chinese invention patent CN105114128A discloses a turbine blade structure that combines air cooling and heat pipe heat transfer. This blade structure incorporates a heat pipe capillary wick inside the blade, containing a liquid working fluid, and utilizes the outer wall of the blade and the outer wall of the bypass duct condensation section to form a closed cavity. While this method proposes a novel approach to blade cooling through a circulating phase change of the working fluid between the outer wall and the bypass duct, it does not fully realize the benefits of this approach. However, this structure, which uses capillary heat pipes closely attached to the inner wall of the blade, is completely different from the current mainstream air-cooled blade structure. Furthermore, the lack of developed processes for assembling nickel-based superalloy heat pipe capillary cores with thin-walled blades in confined spaces, as well as for filling and sealing irregularly shaped phase change working fluids, makes mass production of this structure difficult with current precision investment casting technology. Additionally, the capillary heat pipes are only located at the relatively thick leading edge and middle section of the blade, still failing to solve the problem of high-temperature ablation in the blade tip and trailing edge regions. Moreover, most commonly used high-temperature phase change materials are molten metals, and capillary action alone is insufficient to drive the flow of the phase change working fluid, resulting in insufficient cooling effect from the heat pipes. Therefore, it cannot meet the design requirements of turbine blades in the current aerospace propulsion field. Summary of the Invention

[0005] To address the ablation problem in the trailing edge region of turbine blades in existing technologies, this invention provides a heat pipe cooling structure, method, and blade for the trailing edge of turbine blade tips.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a heat pipe cooling structure for the trailing edge of a turbine blade, comprising a heat pipe inserted into the trailing edge of the blade tip, a trailing edge slit formed on the trailing edge of the blade tip, and an internal cooling channel formed inside the trailing edge of the blade tip; the cold end of the heat pipe extends into the internal cooling channel of the trailing edge of the blade tip, and the hot end of the heat pipe is embedded inside the trailing edge of the blade tip; the trailing edge slit communicates with the internal cooling channel of the trailing edge of the blade tip. The phase change working fluid inside the heat pipe includes sodium and potassium.

[0007] Optionally, the heat pipe includes a heat pipe shell, and a capillary flow guiding layer is provided on the inner wall of the heat pipe shell. The phase change working fluid inside the heat pipe absorbs heat and vaporizes at the hot end of the heat pipe and flows from the inner cavity of the heat pipe to the cold end of the heat pipe. The phase change working fluid inside the heat pipe releases heat and liquefies at the cold end of the heat pipe and returns to the hot end of the heat pipe through the capillary action of the capillary flow guiding layer.

[0008] Optionally, the phase change working fluid inside the heat pipe may also include one or more of magnesium, zinc, titanium, and bismuth.

[0009] Optionally, the average working pressure inside the heat pipe is 1.4 to 3.2 MPa.

[0010] Optionally, the cold end working temperature of the heat pipe is equal to the temperature of the internal cooling gas in the internal cooling channel of the tip shroud, and the hot end working temperature of the heat pipe is equal to the temperature of the fluid outside the tip shroud.

[0011] Optionally, the tip shroud is provided with a tip shroud hole in communication with the internal cooling channel of the tip shroud, and the heat pipe is inserted into the tip shroud hole.

[0012] Optionally, the angle between the axis of the tip shroud hole and the end surface of the tip shroud is greater than 53°.

[0013] Optionally, the inner cavity of the cold end of the heat pipe is in the shape of an ellipse, a triangle or a square.

[0014] A turbine blade comprising the heat pipe cooling structure for the tip shroud of the turbine blade.

[0015] A cooling method using the heat pipe cooling structure for the tip shroud of the turbine blade, comprising: When the blade rotates, a pressure gradient in the same direction as the centrifugal force from the blade root to the blade tip is formed in the heat pipe; Under the action of the centrifugal force from the blade root to the blade tip, the phase change working medium in the heat pipe flows to the blade tip to absorb the heat of the tip shroud and vaporizes at the hot end of the heat pipe; Under the action of the pressure gradient, the vaporized phase change working medium flows to the cold end of the heat pipe and is cooled and liquefied through the internal cooling channel of the tip shroud; Under the action of the centrifugal force from the blade root to the blade tip, the liquefied phase change working medium continues to flow to the blade tip to absorb the heat of the tip shroud and vaporizes at the hot end of the heat pipe, completing a cooling cycle and realizing the cooling of the tip shroud.

[0016] Compared with the prior art, the present application has the following beneficial effects: The application provides a heat pipe type cooling structure for a turbine blade tip trailing edge, which realizes effective cooling of the tip trailing edge by arranging a heat pipe with an internal phase change working medium of sodium and potassium on the tip trailing edge, in combination with a trailing edge split slot arranged on the tip trailing edge and an internal tip trailing edge cooling channel arranged inside the tip trailing edge; in the cooling process, the centrifugal force from the blade root to the tip is used to form a pressure gradient in the heat pipe in the same direction as the centrifugal force; under the centrifugal force from the blade root to the tip, the phase change working medium in the heat pipe flows to the hot end of the heat pipe to absorb heat of the tip trailing edge and vaporize; at the same time, the vaporized phase change working medium flows to the cold end of the heat pipe and is cooled and liquefied through the internal tip trailing edge cooling channel; under the centrifugal force from the blade root to the tip, the liquefied phase change working medium continues to flow to the hot end of the heat pipe to absorb heat of the tip trailing edge and vaporize, so as to realize cooling of the tip trailing edge; the structure is simple and reliable, uses the centrifugal force of the blade rotation as a driving force, and does not need an external pumping device to realize circulation of the phase change working medium in the heat pipe, cooperates with the internal tip trailing edge cooling channel and the trailing edge split slot, uses the high heat transfer performance of potassium and sodium, can cope with a wide range of cascade flow conditions, that is, when the air attack angle, flow and tip vortex change, the tip trailing edge can still be effectively cooled, and the cooling is highly targeted and has high cooling efficiency; the structure does not need to overturn the existing blade production form, only needs to punch and install on the existing blade, the heat pipe is a general profile, is uniformly filled and packaged, is easy to process and transform, has high operability, can be applied to transformation of different turbine blades, and has low transformation cost.

[0017] The heat pipe comprises a heat pipe shell, the inner wall of the heat pipe shell is provided with a capillary flow guiding layer, the internal phase change working medium of the heat pipe is vaporized by heat absorption of the hot end of the heat pipe and flows to the cold end of the heat pipe from the inner cavity of the heat pipe; the internal phase change working medium of the heat pipe is liquefied by heat release of the cold end of the heat pipe and returns to the hot end of the heat pipe through the capillary action of the capillary flow guiding layer, the heat pipe uses the composite circulation mechanism of the capillary flow guiding layer and the centrifugal force to significantly improve the cooling efficiency and reliability of the tip trailing edge of the turbine blade.

[0018] The internal phase change working medium of the heat pipe further comprises magnesium and / or zinc, magnesium and zinc are added as boiling point adjusting metal elements to ensure that the metal molten liquid can be vaporized at the hot end of the heat pipe and liquefied at the cold end of the heat pipe in time in the phase change process. The mass ratio of magnesium and zinc in the phase change working medium is not more than 13%. The internal phase change working medium of the heat pipe further comprises titanium and / or bismuth, the addition of titanium and bismuth and other metal elements for controlling phase change stability can effectively prevent the stratification of several metal elements due to different boiling points in the phase change process, thereby reducing the heat exchange efficiency. The mass ratio of titanium and bismuth in the phase change working medium is not more than 10%.

[0019] The sodium-potassium ratio of the phase change working medium is different according to the application environment of the turbine blade, for the aviation engine turbine blade with compact structure and high working environment temperature, the mass ratio of sodium is 40% to 75%, and for the heavy gas turbine blade with larger size and moderate working environment temperature, the mass ratio of sodium is 35% to 55%.

[0020] The working temperature of the cold end of the heat pipe is equal to the temperature of the cold gas in the internal cooling channel of the blade tip trailing edge, and the working temperature of the hot end of the heat pipe is equal to the temperature of the fluid outside the blade tip trailing edge, so that the heat exchange efficiency can be effectively improved.

[0021] The blade tip trailing edge is provided with a blade tip trailing edge hole in communication with the internal cooling channel of the blade tip trailing edge, and the heat pipe is inserted into the blade tip trailing edge hole, so that the installation of the heat pipe is facilitated, and the processing cost is low.

[0022] The angle between the axis of the blade tip trailing edge hole and the end face of the blade tip trailing edge is greater than 53°, so that the internal heat pipe can form a pressure gradient in the same direction as the centrifugal force under the action of the centrifugal force, thereby providing power for the phase change working medium to flow to the cold end of the heat pipe, improving the heat exchange efficiency and stability.

[0023] The inner cavity shape of the cold end cross section of the heat pipe is an ellipse, a triangle or a square, the elliptical cross section has the characteristics of small flow resistance, and the heat exchange efficiency can be effectively improved; the triangular and square polygon cross sections have strong disturbance effect, and the heat exchange coefficient of the heat pipe and the cold gas can be effectively increased.

[0024] The present application provides a turbine blade comprising the heat pipe cooling structure for the blade tip trailing edge of the turbine blade. The turbine blade realizes the triple breakthrough of "high-efficiency heat transfer-lightweight structure-extreme environment resistance" by integrating the heat pipe cooling structure, has low modification cost, provides a revolutionary solution for the cooling of the hot end components of the aviation engine, and is expected to have wide application prospects in future high thrust-to-weight ratio and low emission engines, and can be popularized to high-temperature hot end fields such as gas turbines and rocket engines.

[0025] The present application also provides a cooling method using the heat pipe cooling structure for the blade tip trailing edge of the turbine blade. The cooling method cleverly utilizes the centrifugal force generated by the rotation of the turbine blade and the physical properties of the phase change working medium in the heat pipe to construct a self-driven, high-efficiency and full-working-condition-adaptive closed-loop cooling system. The closed-loop cooling system completely utilizes the centrifugal force generated by the rotation of the blade to drive the flow of the phase change working medium, does not need an external power source, overturns the traditional "passive heat dissipation" logic of air cooling, realizes "active heat transfer", and can significantly reduce the life cycle cost of the engine, thereby providing a key technical path for the lightweighting, high efficiency and long service life of high-temperature hot end components such as aviation engines and gas turbines. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A cross-sectional view of a heat pipe cooling structure for a turbine blade tip shroud according to the present invention.

[0027] Figure 2 A perspective view of a heat pipe cooling structure for a turbine blade tip shroud according to the present invention.

[0028] Figure 3 A longitudinal cross-sectional view of a heat pipe of a heat pipe cooling structure according to the present invention.

[0029] Figure 4 A longitudinal cross-sectional view of a heat pipe cooling structure for a turbine blade tip shroud according to the present invention.

[0030] Figure 5 A structure view of different shapes of a heat pipe of a heat pipe cooling structure according to the present invention.

[0031] Figure 6 A flow chart of a method for cooling a turbine blade tip shroud using a heat pipe cooling structure for a turbine blade tip shroud according to the present invention.

[0032] Wherein, 1 - tip shroud, 2 - heat pipe, 10 - tip shroud hole, 11 - tip shroud top surface, 12 - tip shroud internal cooling channel, 13 - shroud split, 14 - heat transfer direction from tip shroud to heat pipe, 15 - heat transfer direction from heat pipe to cooling medium, 21 - heat pipe hot end, 22 - heat pipe cold end, 23 - heat pipe shell, 24 - capillary flow layer, 25 - phase change medium heat absorption vaporization flow direction, 26 - phase change medium heat release liquefaction flow direction. DETAILED DESCRIPTION

[0033] In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following will be combined with the accompanying drawings for the embodiments of the present invention to make a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but only represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0035] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0036] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0037] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0038] In the description of the embodiments of the present application, it should also be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] The present application will be further described in detail below in conjunction with specific embodiments, which are an explanation of the present application rather than a limitation.

[0040] The present application discloses a heat pipe type cooling structure for a turbine blade tip trailing edge, referring to Figure 1 and Figure 2 , comprising a heat pipe 2 inserted in the tip trailing edge 1, a trailing edge split 13 opened on the tip trailing edge 1, and a tip trailing edge internal cooling channel 12 opened inside the tip trailing edge 1. The tip trailing edge 1 is provided with a tip trailing edge hole 10, the included angle between the axis of the tip trailing edge hole 10 and the tip trailing edge end face is greater than 53°, the tip trailing edge hole 10 is in communication with the tip trailing edge internal cooling channel 12, and the heat pipe 2 is inserted into the tip trailing edge hole 10. The tip trailing edge hole 10 can adopt the same processing mode as the gas film hole of the air-cooled blade, or can adopt a corresponding appropriate processing mode according to the specific blade and the geometric configuration of the hole, including but not limited to laser drilling, mechanical drilling, electric spark drilling, and electro-hydraulic beam drilling.

[0041] The cold end 22 of the heat pipe 2 extends into the internal cooling channel 12 of the tip trailing edge 1, and the hot end 21 of the heat pipe 2 is embedded in the tip trailing edge 1; the trailing edge split 13 is in communication with the internal cooling channel 12 of the tip trailing edge, and the phase-change working medium in the heat pipe 2 comprises sodium and potassium. Optionally, the working temperature range of the heat pipe 2 is 950-1400K. See Figure 2 and Figure 3The heat pipe 2 comprises a heat pipe shell 23, the inner wall of which is provided with a capillary flow guiding layer 24, and the phase change working medium inside the heat pipe 2 is vaporized by the heat pipe hot end 21, flows to the heat pipe cold end 22, and is liquefied by the heat pipe cold end 22, and returns to the heat pipe hot end 21 through the capillary action of the capillary flow guiding layer 24. The phase change working medium inside the heat pipe 2 can also contain magnesium, zinc and other single-component metals for adjusting the boiling point, so as to ensure that the metal molten liquid can be vaporized at the hot end and liquefied at the cold end in time during the phase change process. Meanwhile, the phase change working medium contains titanium, bismuth and other single-component metals for controlling the phase change stability, so as to prevent the stratification of the phase change working medium due to the difference in the boiling points of the several metal components during the phase change process, and thus prevent the heat exchange efficiency from being reduced. The mass proportion of the magnesium and zinc in the phase change working medium is not more than 13%, and the mass proportion of the titanium and bismuth in the phase change working medium is not more than 10%. The proportion of each metal component and the internal filling pressure can be adjusted according to the actual working temperature environment of the blade, provided that the lower limit of the working temperature range of the heat pipe 2 is about the temperature of the cold gas inside the internal cooling channel 12 near the blade tip trailing edge, and the upper limit is about the temperature of the fluid outside the blade tip trailing edge 1. Meanwhile, the internal pressure of the heat pipe 2 is adjusted according to the gas pressure environment, so as to prevent the heat pipe shell 23 from being damaged due to the excessively large pressure difference. For the aero-engine turbine blade with compact structure and high working temperature environment, the mass proportion of sodium is 40% to 75%, and for the heavy gas turbine blade with larger size and moderate working temperature environment, the mass proportion of sodium is 35% to 55%. In order to adjust the boiling point of the internal phase change working medium and balance the gas pressure of the turbine blade, the average internal pressure of the heat pipe during the working process is usually controlled in the range of 1.4 to 3.2 MPa. The heat pipe shell 23 is made of high-temperature alloy, and the same material as the blade can be used. Other materials that are beneficial to the production and processing of the heat pipe can also be used, and the allowable temperature of the material is within 50 K lower than the allowable temperature of the blade material, and the thermal expansion coefficient is similar, so as to prevent the blade structure from being damaged due to high temperature or thermal stress. In order to ensure the strength of the hole wall of the blade tip trailing edge hole 10 and the processing success rate, the hole wall should not be too thin, and in order to improve the heat exchange efficiency of the heat pipe, the diameter of the heat pipe 2 should not be too small. Therefore, the ratio of the diameter of the heat pipe 2 to the fillet diameter of the blade tip trailing edge 1 is in the range of 0.2 to 0.8. The upper end surface of the heat pipe 2 is flush with the top surface 11 of the blade tip trailing edge, so as to prevent the blade tip flow from being adversely affected or colliding with the casing. The upper end surface of the heat pipe 2 and the part of the heat pipe 2 that is in contact with the inner wall of the blade tip trailing edge hole 10 are the heat pipe hot end 21, and the part of the heat pipe 2 that extends into the internal cooling channel of the blade tip trailing edge is the heat pipe cold end 22. The length of the heat pipe cold end 22 is not more than the width of the cooling channel in the current orientation, so as to prevent the heat pipe from being in contact with the internal structure of the blade and being unable to be assembled. The length of the heat pipe 2 is the sum of the length of the blade tip trailing edge hole 10 and the length of the cold end.

[0042] When working, the high-speed rotation of the blade forms a centrifugal force from the blade root to the blade tip, and a pressure gradient in the same direction as the centrifugal force is formed in the heat pipe 2, i.e. from the cold end 22 to the hot end 21 of the heat pipe. The molten metal in the heat pipe 2 flows to the hot end 21 of the heat pipe under the action of the centrifugal force and the capillary action along the capillary flow layer 24 on the inner wall of the heat pipe 2. The heat pipe shell 23 at the hot end 21 of the heat pipe absorbs the heat of the blade and transfers it to the molten metal in the heat pipe, and the molten metal absorbs the heat and vaporizes. The high-temperature metal vapor has a lower density than the molten metal and the low-temperature metal vapor at the cold end, and flows to the cold end of the heat pipe through the hollow channel in the center of the heat pipe under the driving of the pressure gradient, i.e. the flow direction 25 of the phase-change working medium after absorbing heat and vaporizing. The heat pipe cold end 22 absorbs the heat of the flowing metal vapor and dissipates it to the surrounding cooling medium through the heat pipe shell 23, and the metal vapor in the heat pipe 2 releases heat and liquefies. The liquefied metal flows to the hot end under the action of the centrifugal force and the capillary action along the capillary flow layer 24 on the inner wall of the heat pipe 2, i.e. the flow direction 26 of the phase-change working medium after releasing heat and liquefying. Thus, the heat at the hot end 21 of the heat pipe is efficiently transferred to the cold end 21 of the heat pipe through phase change.

[0043] Referring to Figure 4 , the overall heat transfer mode of the heat pipe cooling structure of the tip trailing edge is that the high-temperature combustion gas around the tip trailing edge continuously and strongly heats the tip trailing edge 1 through the top surface 11 of the tip trailing edge and the side surface of the blade. The heat pipe hot end 21 is closely attached to the tip trailing edge hole 10, and the heat is quickly transferred to the heat pipe hot end 21 through heat conduction, and the tip trailing edge transfers heat to the heat pipe, and the heat pipe transfers heat to the cooling medium, referring to Figure 4 . The heat pipe 2 efficiently transfers heat to the heat pipe cold end 21 due to the above-mentioned working medium migration and phase change. The cooling medium in the internal cooling channel 12 of the tip trailing edge flows through the heat pipe cold end 22 and takes away the heat of the heat pipe cold end 22, and finally the cooling medium flows out of the blade from the trailing edge split joint 13 and merges with the main flow to take away the heat from the blade.

[0044] Overall, due to the special structure of the present application, the centrifugal force better drives the working medium migration in the heat pipe 2, and the heat pipe 2 as an intermediate medium efficiently transfers the heat in the high-temperature area of the tip trailing edge 1 to the cooling medium and discharges it, so that the tip trailing edge region is well cooled. From the above process, it can be seen that the overall heat transfer process does not depend on the flow details and specific organization of the external combustion gas and the internal cooling medium, and can still effectively cool the tip trailing edge when the flow conditions of the blade row, i.e. the flow angle, the flow rate and the tip vortex system, change.

[0045] Referring to Figure 5, considering that the cold end 22 of the heat pipe is located in the internal cooling channel 12 of the tip trailing edge, different geometrical shapes will bring different flow effects and convection cooling characteristics. Under the premise that the minimum circumscribed circle diameter of the cross section of the cold end 22 of the heat pipe 2 is less than or equal to the diameter of the tip trailing edge hole 10, that is, the heat pipe 2 can be inserted and assembled through the tip trailing edge hole 10, the cold end section can be designed into other geometric shapes, including other cold end shape examples of the heat pipe: the cold end 22 section can be designed into an elliptical section with small flow resistance, or a polygonal section with rounded corners, such as a triangular section and a quadrilateral section. The three subgraphs in the drawings of the present application are only examples, and other cold end section shapes that meet the requirement of the minimum circumscribed circle diameter being less than or equal to the diameter of the tip trailing edge hole are within the scope of the present application.

[0046] The present application provides a turbine blade comprising the heat pipe cooling structure for the tip trailing edge of the turbine blade described above. The turbine blade realizes the triple breakthrough of "high-efficiency heat transfer-lightweight structure-extreme environment resistance" by integrating the heat pipe cooling structure, has low modification cost, provides a revolutionary solution for cooling of the hot end components of the aero-engine, is expected to have wide application prospects in future high-thrust-to-weight ratio and low-emission engines, and can be popularized to high-temperature hot end fields such as gas turbines and rocket engines.

[0047] Referring to Figure 6 The present application also provides a cooling method using the heat pipe cooling structure for the tip trailing edge of the turbine blade described above, comprising: S1: forming a pressure gradient in the heat pipe 2 in the same direction as the centrifugal force from the blade root to the tip during rotation of the blade; S2: under the action of the centrifugal force from the blade root to the tip, making the phase change working medium in the heat pipe 2 flow to the tip direction to the heat end 21 of the heat pipe to absorb heat of the tip trailing edge and vaporize; S3: under the action of the pressure gradient, making the vaporized phase change working medium flow to the cold end 22 of the heat pipe and be cooled and liquefied through the internal cooling channel 12 of the tip trailing edge; S4: under the action of the centrifugal force from the blade root to the tip, continuously making the liquefied phase change working medium flow to the tip direction to the heat end 21 of the heat pipe to absorb heat of the tip trailing edge and vaporize, completing a cooling cycle and realizing cooling of the tip trailing edge.

[0048] The cooling method constructs a self-driven, high-efficiency and full-working-condition-adapted closed-loop cooling system by skillfully utilizing centrifugal force generated by turbine blade rotation and physical properties of phase change working medium in the heat pipe. The closed-loop cooling system completely utilizes centrifugal force generated by blade rotation to drive the flow of phase change working medium, does not need an external power source, overturns the traditional air cooling 'passive heat dissipation' logic, realizes 'active heat carrying', can significantly reduce the full life cycle cost of the engine, and provides a key technical path for lightweight, high efficiency and long life of high-temperature hot end components such as aircraft engines and gas turbines.

[0049] The above merely describes the preferred embodiments of the present application and is not intended to limit the technical solutions of the present application in any way. Those skilled in the art should understand that, without departing from the spirit and principle of the present application, the technical solutions can also be modified and replaced in several simple ways, and these modifications and replacements also belong to the protection scope covered by the claims.

Claims

1. A heat pipe cooling structure for a turbine blade tip shroud, characterized by, The heat pipe is inserted into the trailing edge of the blade tip, the trailing edge split slot is opened on the trailing edge of the blade tip, and the internal trailing edge cooling channel is opened inside the trailing edge of the blade tip; the cold end of the heat pipe extends into the internal trailing edge cooling channel, and the hot end of the heat pipe is embedded in the internal trailing edge of the blade tip; the trailing edge split slot is communicated with the internal trailing edge cooling channel. The internal phase change working medium of the heat pipe comprises sodium and potassium.

2. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The heat pipe comprises a heat pipe shell, and a capillary flow guiding layer is arranged on the inner wall of the heat pipe shell; the internal phase change working medium of the heat pipe is vaporized by the heat pipe hot end to flow from the heat pipe cavity to the heat pipe cold end; and the internal phase change working medium of the heat pipe is liquefied by the heat pipe cold end to return to the heat pipe hot end through the capillary action of the capillary flow guiding layer.

3. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The internal phase change working medium of the heat pipe further comprises one or more of magnesium, zinc, titanium and bismuth.

4. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The average working pressure of the internal phase change working medium of the heat pipe is 1.4-3.2 MPa.

5. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The working temperature of the heat pipe cold end is equal to the temperature of the cold gas in the internal trailing edge cooling channel, and the working temperature of the heat pipe hot end is equal to the temperature of the fluid outside the trailing edge of the blade tip.

6. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The trailing edge hole is arranged on the trailing edge of the blade tip, the trailing edge hole is communicated with the internal trailing edge cooling channel, and the heat pipe is inserted into the trailing edge hole.

7. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The angle between the axis of the trailing edge hole and the end surface of the trailing edge of the blade tip is greater than 53°.

8. The heat pipe cooling structure for a turbine blade tip shroud according to claim 1, characterized by, The cross-sectional cavity shape of the heat pipe cold end is an ellipse, a triangle or a square.

9. A turbine blade, characterized by The heat pipe type cooling structure for the trailing edge of the turbine blade tip comprises the heat pipe type cooling structure for the trailing edge of the turbine blade tip according to any one of claims 1-8.

10. Cooling method for a heat pipe cooling structure for a turbine blade tip shroud according to any one of claims 1 to 8, characterized in that The heat pipe type cooling structure for the trailing edge of the turbine blade tip comprises the heat pipe type cooling structure for the trailing edge of the turbine blade tip according to any one of claims 1-8. When the blade rotates, a pressure gradient in the same direction as the centrifugal force from the blade root to the blade tip is formed in the heat pipe; Under the action of the centrifugal force from the blade root to the blade tip, the internal phase change working medium of the heat pipe flows to the hot end of the heat pipe in the direction of the blade tip to absorb the heat of the trailing edge of the blade tip and vaporize; Under the action of the pressure gradient, the vaporized phase change working medium flows to the cold end of the heat pipe and is liquefied through the internal trailing edge cooling channel of the trailing edge of the blade tip; Under the action of the centrifugal force from the blade root to the blade tip, the liquefied phase change working medium continues to flow to the hot end of the heat pipe in the direction of the blade tip to absorb the heat of the trailing edge of the blade tip and vaporize, thereby completing a cooling cycle and realizing the cooling of the trailing edge of the blade tip.

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