Turbine moving blade with internal cooling channel provided with dustproof structure

Abstract

A turbine moving blade with an internal cooling channel with a dustproof structure comprises a rotational flow cavity arranged between ribbed U-shaped cooling channels in the moving blade, the rotational flow cavity is connected with the cooling channels with inclined ribs through square nozzles, and the top of the rotational flow cavity shrinks and is connected with a blade top dust removal hole through a hollow turbulent flow column of a channel elbow. Under the rotating condition, particulate pollutants in the channel are gathered on the pressure face side of the channel and then enter the rotational flow cavity from the square nozzle under induction of the inclined ribs. Tangently-incident cold air forms rotational flow in the rotational flow cavity, particles are difficult to deposit in the rotational flow cavity due to the high tangential speed, and the particles can only enter the hollow channels of the turbulent flow columns along with the cold air and finally flow out of the blades through the blade top dust removal holes. Under limited cold air consumption, particles are separated from cold air and discharged out of the blades through rotation, the guiding effect of the turbulent flow ribs and inertia of the particles, and the heat transfer uniformity of the blades is optimized through rotational flow cooling.

Description

Technical Field

[0001] The invention belongs to the technical field of cooling turbine blades of aircraft engines or heavy-duty gas turbines, and in particular relates to a turbine blade having an internal cooling channel with a dustproof structure. Background Art

[0002] In pursuit of higher cycle efficiency, the inlet temperature of aircraft engine turbines has been increasing, even exceeding the heat resistance limit of the metal used for turbine blades. In order to protect the blades from being burned by high-temperature airflow, a large number of cooling structures (such as serpentine channels, impact holes, air film holes, spoiler ribs and spoiler columns, etc.) are usually arranged inside the blades to allow the low-temperature cold air from the compressor to take away the heat in the form of forced convection heat exchange, thereby achieving the purpose of protecting the blades.

[0003] The normal operation of aircraft engines is not only related to their own structure, but also closely related to the operating environment. When humans are exposed to particulate pollutants for a long time, if there are no protective measures, the particulate matter will penetrate into the human respiratory system and cause obstructive pulmonary disease (OPD). When aircraft engines operate for a long time in an environment with high concentrations of particulate matter, the particulate matter will also cause serious damage to the aero-thermal performance of aircraft engines.

[0004] In the high temperature, high pressure and high speed operating environment outside the turbine blades, particulates are very easy to deposit on the surface of the turbine blades. On the one hand, the deposits will corrode the thermal barrier coating of the blades, resulting in reduced or even complete failure of its thermal insulation effect; on the other hand, the deposits will increase the surface roughness of the blades, enhance the heat exchange between the high temperature mainstream and the blades, and the blades will face a higher risk of burning. In addition, the deposits will change the blade profile, causing the blades to deviate from the optimal design conditions and thus reduce the overall gas thermal efficiency. In addition to the outside of the blades, particulates will also enter the inside of the turbine blades through the secondary air system. On the one hand, the cold air temperature is lower than the softening temperature of the particulates and the complex cooling structure interacts with each other, so the particulates show a unique deposition mechanism, which makes it impossible to predict the hazards of deposition using the relatively mature high temperature deposition mechanism; on the other hand, the small internal space will amplify the impact of the deposits on the performance of the blades and make them difficult to remove. After entering the blade, the particles first reach the cooling channel. In the common arrangement with spoiler ribs, the particles will adhere to the inner wall of the channel and hinder the cold air from taking away the heat in the blade metal through its low thermal conductivity. They will also accumulate in the corner area of ​​the rib wall to weaken the enhanced heat exchange effect of the spoiler ribs. Further, the deposits will block the cooling channel and increase the flow loss. Therefore, a structure that can effectively reduce the concentration of particles in the cooling channel inside the turbine blade and thus reduce the adverse effects of the deposits on the thermal performance of the cold air is urgently needed to be developed. However, in the published literature, the dust-proof structures that can be applied to the internal cooling structure are very limited. Yang Xing et al. (PCN240010217) arranged a bag-shaped sedimentation reduction structure at the front end of the turbine blade cooling channel. Although it can capture particulate pollutants and increase the turbulence of the cold air, this is achieved at the cost of the flow loss of the cold air. Summary of the invention

[0005] The object of the present invention is to provide a turbine blade having an internal cooling channel with a dust-proof structure, so as to solve the technical defect that the internal cooling channel of the existing turbine blade is difficult to capture particulate pollutants.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0007] A turbine rotor blade with a dustproof structure in an internal cooling channel, wherein a swirl cavity 4 is provided between a U-shaped cooling channel 1 with ribs inside a turbine rotor blade 9, and the U-shaped cooling channel 1 and the swirl cavity 4 are connected through a square nozzle 3 on the pressure surface side of the ribbed U-shaped cooling channel; after the cold air carrying particulate pollutants enters the U-shaped cooling channel 1 inside the turbine rotor blade 9 rotating from the pressure surface to the suction surface, the particulate matter will be deflected to the opposite side of the rotation direction under the action of the Coriolis force, and will be gathered in the inter-rib area on the pressure surface side of the U-shaped cooling channel, and then will be dispersed in the inclined perturbation nozzle 3 on the U-shaped cooling channel at an acute angle to the flow direction of the cold air. Under the guidance of the flow ribs 2, the particles move toward the leading edge of the inclined spoiler ribs 2, and then enter the swirl chamber 4 through the square nozzle 3; the cold air carrying the particles spirals forward in the swirl chamber 4, which on the one hand enhances the forced convection heat transfer capacity of the inner wall of the turbine blade cavity, and on the other hand, the increased tangential velocity near the wall makes it difficult for the particles to deposit in the swirl chamber 4; the top of the swirl chamber is a contraction section 5, which reaches the blade top dust removal hole 8 through the hollow channel of the hollow spoiler column 7 arranged at the U-shaped cooling channel elbow 6, and finally the particulate pollutants are discharged from the turbine blade 9, and the cleanliness of the cold air in the internal U-shaped cooling channel is significantly improved.

[0008] The turbine blades 9 and their internal cooling structure are in a rotating condition pointing from the pressure surface to the suction surface. The square nozzle 3 is arranged on the pressure surface side of the U-shaped cooling channel to ensure that the particles can be guided to a position close to the square nozzle under the action of the Coriolis force.

[0009] The swirl chamber 4 is arranged between the U-shaped cooling channels 1 and is connected to the air inlet path of the U-shaped cooling channels 1 through the square nozzle 3 .

[0010] The inclined spoiler ribs 2 in the U-shaped cooling channel 1 point toward the swirl cavity 4 along the cold air flow direction in the inlet air flow path, and the angle between the extending direction of the spoiler ribs 2 and the flow direction of the cold air in the cold air flow path is between 20° and 70°.

[0011] The square nozzle 3 is tangent to the pressure surface of the U-shaped cooling channel 1 and the swirl chamber 4 respectively, which not only reduces the flow loss, but also allows the cold air to be tangentially injected into the swirl chamber 4 to form a swirl.

[0012] The inclination direction of the square nozzle 3 is consistent with the spoiler rib 2 , which reduces flow loss on the one hand and makes it easier to form a cold air vortex in the vortex cavity 4 pointing to the blade tip on the other hand.

[0013] The square nozzle 3 is not continuous, but is separated by multiple partitions 10. The flow direction size and position of the partition 10 are consistent with the flow direction section of the local inclined spoiler rib, and the height of the partition 10 is 0.5 to 3 times the height of the inclined spoiler rib; the presence of the partition 10 increases the stability of the structure and reduces the probability of particles escaping from the vortex chamber.

[0014] The top of the cyclone chamber 4 gradually shrinks, and its final size is equivalent to the dust removal hole on the blade top.

[0015] A hollow spoiler column 7 is arranged at the elbow 6 of the U-shaped cooling channel. The hollow spoiler column can enhance the turbulence of the cold air and improve the heat exchange capacity of the cold air. The hollow channel therein can allow the top of the contracted swirl cavity to pass through and directly reach the dust removal hole 8 on the blade top.

[0016] The square nozzles 3 are arranged one by one between the first and second ribs of the air intake passage, and the number of the square nozzles 3 is between 3 and 7.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The swirl formed by the cold air in the swirl chamber gives the inner wall of the chamber a higher tangential velocity near the wall, making it difficult for particles to deposit in the swirl chamber.

[0019] (2) The present invention has a compact structure, and the swirl chamber arranged between the U-shaped cooling channels does not occupy the space of other cooling structures.

[0020] (3) The present invention utilizes rotation and rib-induced secondary flow to guide particles having a higher Stokes number than the cold air to a specific area, thereby facilitating separation.

[0021] (4) The square nozzle of the present invention is arranged between the first and second spoiler ribs. Compared with the traditional dust removal holes arranged in elbows, it can separate particles from the U-shaped cooling channel earlier, thereby reducing the probability of particle deposition inside the blade.

[0022] (5) The present invention utilizes the dust removal holes on the blade tops to significantly reduce the concentration of particulate matter in the internal cooling channels under limited cooling air consumption, improve the heat exchange between the cooling channels, and optimize the overall heat transfer uniformity of the blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 This is a view of the hub of the present invention facing the casing surface.

[0025] Figure 3 The migration trajectory of particles in the internal U-shaped cooling channel with ordinary dust removal holes.

[0026] Figure 4 The migration trajectory of particles in the internal U-shaped cooling channel with dust-proof structure.

[0027] Figure 5 The concentration of particulate matter in the channel decreases and the cooling air consumption.

[0028] Figure 6 Nusselt number distribution on the surface of the internal U-shaped cooling channel with dustproof structure.

[0029] Among them: 1-U-shaped cooling channel, 2-spoiler rib, 3-square nozzle, 4-swirl chamber, 5-contraction section, 6-U-shaped cooling channel elbow, 7-hollow spoiler column, 8-blade top dust removal hole, 9-turbine moving blade, 10-partition. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments. This embodiment provides a detailed implementation method according to the above technical solution, but this embodiment is only a specific implementation method of the present invention, and any equivalent changes based on the technical principle of the present invention belong to the protection scope of the claims of the present invention.

[0031] like Figure 1 As shown, the present invention discloses a turbine impeller with an internal cooling channel and a dust-proof structure, wherein a swirl chamber 4 is provided between a U-shaped cooling channel 1 with an inclined spoiler rib 2 inside a turbine impeller 9, and the U-shaped cooling channel 1 and the swirl chamber 4 are connected and kept tangent through a square nozzle 3. The top of the swirl chamber 4 gradually converges to form a contraction section 5, and the hollow spoiler column 7 arranged in the elbow 6 of the U-shaped cooling channel directly reaches the dust removal hole 8 on the blade top.

[0032] like Figure 1 As shown, the square nozzle 3 is not continuous, but is separated by a plurality of partitions 10. The flow direction size and position of the partition 10 are consistent with the flow direction section of the local inclined spoiler rib, and the height of the partition 10 is 0.5 to 3 times the height of the inclined spoiler rib. The presence of the partition 10 increases the stability of the structure and reduces the probability of particles escaping from the swirl chamber.

[0033] The working process of the present invention using the swirl structure to reduce the concentration of particulate matter in the cooling channel inside the turbine blade is as follows: small-size particles crushed by the high-speed rotating compressor blades enter the U-shaped cooling channel 1 inside the turbine blade 9 through the secondary air system. Under the rotation condition from the pressure surface to the suction surface, the particles are gathered to the pressure surface side of the cooling channel due to the Coriolis force, and then, under the guidance of the inclined spoiler ribs 2, the cold air carries the particles through the square nozzle 3 into the swirl chamber 4. Under the action of the cold air swirl, it is difficult for the particles to deposit on the inner wall of the swirl chamber 4 with a large tangential velocity, so they are carried by the cold air and spiral into the contraction section 5 at the top of the swirl chamber 4, and then reach the blade top dust removal hole 8 through the hollow channel of the hollow spoiler column 7 arranged in the U-shaped cooling channel elbow 6, and finally the particles are discharged from the turbine blade 9.

[0034] Figure 2This is a view of the hub of the present invention facing the casing surface. From this angle, it is obvious that the square nozzle 3 is tangent to the swirl chamber 4 and the U-shaped cooling channel 1. For the U-shaped cooling channel 1, the tangent connection can minimize the flow loss; for the swirl chamber 4, the cold air tangentially incident through the square nozzle 3 will form a swirl in the swirl chamber, which can be used to discharge particles on the one hand, and on the other hand, it can remove the heat between the U-shaped cooling channels 1 through forced convection heat exchange.

[0035] Figure 3 The migration trajectory of particles in the internal U-shaped cooling channel with ordinary dust removal holes. Under the action of the inclined ribs, a pair of vortices with opposite rotation directions are formed in the internal cooling channel. The cold air carries the particles and collides with the wall surface many times, increasing the probability of particle deposition. In the cooling channel elbow, only a few small-sized particles will follow the cold air out of the blade tip dust removal hole, and most of the particulate pollutants will remain in the U-shaped cooling channel.

[0036] Figure 4 The migration trajectory of particles in the internal U-shaped cooling channel with a dustproof structure of the present invention. After the particles enter the U-shaped cooling channel, they are continuously separated and enter the swirl chamber from the first square nozzle. The separation phenomenon of the first three square nozzles is particularly obvious. The particles spiral forward in the swirl chamber. Due to the inertia of the particles themselves and the continuous entry of cold air into the swirl chamber, it is difficult for the particles to flow back to the U-shaped cooling channel. Finally, the particles converge in the contraction section at the top of the swirl chamber and flow out through the dust removal holes on the blade top. The concentration of particulate pollutants in the U-shaped cooling channel separated by the swirl structure is significantly reduced.

[0037] Figure 5 The concentration of particulate matter in the U-shaped cooling channel decreases and the cold air consumption. Through quantitative analysis, it can be found that the particle separation efficiency of the ordinary dust removal hole is very low. After passing through the dust removal hole, 99.17% of the particles still remain in the cooling channel, which is almost unchanged. After the swirl dustproof structure is added to the present invention, the particle concentration in the cooling channel can be reduced to 42.82% with only a 1% increase in cold air consumption, which greatly improves the separation efficiency of particulate pollutants compared to traditional dust removal holes.

[0038] Figure 6This is the Nusselt number distribution on the surface of the internal U-shaped cooling channel with a dustproof structure of the present invention. The U-shaped cooling channel is used for the flow of cold air from the compressor to take away the heat in the metal of the turbine blades in the form of forced convection heat exchange, thereby protecting the blades from being burned by high temperatures. However, in locations far away from the U-shaped cooling channel (for example, between two cooling channels that are far apart), cooling can only be performed in the form of heat conduction, which has low cooling efficiency and will also cause obvious thermal stress in the blades. Under the extremely high temperature and high-speed operating environment of the turbine blades, excessive thermal stress will significantly reduce the service life of the blades and cause safety hazards. The swirl chamber is arranged between the U-shaped cooling channels, and the swirl formed by the cold air strengthens the cold air heat exchange capacity of the inner wall of the swirl chamber, which can not only enhance the cold air protection capacity of these low heat exchange areas, but also improve the overall heat transfer uniformity of the blades.

[0039] In summary, in order to reduce the damage to aerodynamic characteristics and cooling performance caused by the deposition of particulate pollutants in the internal cooling channel, the present invention provides a turbine blade with a dustproof structure in the internal cooling channel. Under the guidance of the rotation and rib-induced secondary flow, the inertia difference between the particulate matter and the cold air is utilized, and at the cost of a slight increase in cold air consumption, the particulate pollutants are efficiently separated from the cold air and discharged from the blade, thereby improving the cleanliness of the cold air in the internal cooling channel of the blade. The present invention has a simple structure and does not require special processing. It can be realized by using the currently commonly used turbine blade cooling structure processing technology. When using the present invention, a trade-off can be made between the cold air consumption, the particulate separation requirements, and the swirl chamber heat exchange requirements, and the appropriate square nozzle opening size, the number of square nozzles, and the size of the dust removal holes on the blade top can be selected.

[0040] Unless otherwise defined, all terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Claims

1. A turbine rotor blade with an internal cooling channel and a dustproof structure, characterized in that: A swirl chamber (4) is provided between the U-shaped cooling channels (1) inside the turbine blades (9), and the U-shaped cooling channels (1) and the swirl chamber (4) are connected via a square nozzle (3) on the pressure side of the ribbed U-shaped cooling channels; after the cold air carrying particulate pollutants enters the U-shaped cooling channels (1) inside the turbine blades (9) rotating from the pressure side to the suction side, the particulate matter will be deflected to the opposite side of the rotation direction under the action of the Coriolis force, and will gather in the inter-rib area on the pressure side of the U-shaped cooling channels (1), and then, under the guidance of the inclined spoiler ribs (2) located on the U-shaped cooling channels (1) at an acute angle to the flow direction of the cold air, the particulate matter will be moved to the side opposite to the rotation direction. The cooling air moves in the direction of the leading edge of the inclined spoiler rib (2), and then enters the swirl chamber (4) through a square nozzle (3) formed by a partition (10); the cold air entrained with particulate matter spirals forward in the swirl chamber (4), which, on the one hand, strengthens the forced convection heat transfer capacity of the inner wall surface of the turbine blade cavity, and on the other hand, increases the tangential velocity near the wall surface, making it difficult for particulate matter to settle in the swirl chamber (4); the top of the swirl chamber is a contraction section (5), which reaches the blade top dust removal hole (8) through the hollow channel of the hollow spoiler column (7) arranged at the U-shaped cooling channel elbow (6), and finally the particulate pollutants are discharged from the turbine blade (9), and the cleanliness of the cold air inside the blade is significantly improved.

2. The turbine rotor blade with dust-proof structure in the internal cooling channel according to claim 1, characterized in that: The turbine blade (9) and its internal cooling structure are in a rotating condition pointing from the pressure surface to the suction surface, and the square nozzle (3) is arranged on the pressure surface side of the U-shaped cooling channel to ensure that the particles can be guided to a position close to the square nozzle under the action of the Coriolis force.

3. The turbine rotor blade with dust-proof structure in the internal cooling channel according to claim 1, characterized in that: The swirl chamber (4) is arranged between the U-shaped cooling channels (1) and is connected to the air inlet path of the U-shaped cooling channels (1) through the square nozzle (3).

4. The turbine rotor blade with dust-proof structure in the internal cooling channel according to claim 1, characterized in that: The inclined spoiler ribs (2) in the U-shaped cooling channel (1) point toward the swirl chamber (4) along the cold air flow direction in the inlet air flow path, and the angle between the extension direction of the spoiler ribs (2) and the flow direction of the cold air in the cold air flow path is between 20° and 70°.

5. The turbine rotor blade with dust-proof structure for internal cooling passage according to claim 1, characterized in that: The square nozzle (3) is tangent to the pressure surface side of the U-shaped cooling channel (1) and the swirl chamber (4), respectively, which not only reduces flow loss but also allows the cold air to be tangentially injected into the swirl chamber (4) to form a swirl.

6. The turbine rotor blade with dust-proof structure in the internal cooling channel according to claim 1, characterized in that: The inclination direction of the square nozzle (3) is consistent with that of the spoiler rib (2), which reduces flow loss on the one hand and makes it easier to form a cold air vortex pointing towards the blade tip in the vortex cavity (4) on the other hand.

7. The turbine rotor blade with an internal cooling channel and a dustproof structure according to claim 1, characterized in that: The square nozzle (3) is not continuous but is separated by a plurality of partitions (10). The flow direction size and position of the partitions (10) are consistent with the flow direction cross section of the local inclined spoiler ribs, and the height of the partitions (10) is 0.5 to 3 times the height of the inclined spoiler ribs. The presence of the partitions (10) increases the stability of the structure and reduces the probability of particles escaping from the swirl chamber.

8. The turbine rotor blade with dust-proof structure in the internal cooling passage according to claim 1, characterized in that: The top of the cyclone chamber (4) gradually shrinks, and its final size is equivalent to the dust removal hole on the blade top.

9. The turbine rotor blade with dust-proof structure in the internal cooling passage according to claim 1, characterized in that: A hollow spoiler column (7) is arranged at the elbow (6) of the U-shaped cooling channel. The hollow spoiler column can enhance the turbulence of the cold air and improve the heat exchange capacity of the cold air. The hollow channel therein can allow the top of the swirl cavity to pass through after contraction and directly reach the blade top dust removal hole (8).

10. The turbine rotor blade with dust-proof structure for internal cooling passage according to claim 1, characterized in that: The square nozzles (3) are arranged one by one between the first and second ribs of the air inlet passage, and the number of the square nozzles (3) is between 3 and 7.

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