CN111570952A

CN111570952A - Air-cooled hollow blade air film hole inner wall sharp corner rounding device and method

Info

Publication number: CN111570952A
Application number: CN202010385186.2A
Authority: CN
Inventors: 李青; 马宁; 李艳明; 佟文伟; 韩振宇; 张亚雄; 王全
Original assignee: AECC Shenyang Engine Research Institute
Current assignee: AECC Shenyang Engine Research Institute
Priority date: 2020-05-09
Filing date: 2020-05-09
Publication date: 2020-08-25

Abstract

The application belongs to the technical field of engine blade processing, in particular to air-cooled hollow blade air film hole inner wall closed angle radius device and device, the device includes: the electrolyte circulating module comprises an electrolyte tank and a working liquid pool, electrolyte is introduced to the upper part of the working liquid pool from the electrolyte tank through an injection pipe and flows back through a return pipe, and a nozzle of the injection pipe is aligned to a gas film hole of the air-cooled hollow blade in the working liquid pool; the power supply loop comprises a power supply, an electrode rod and a conductive plate, wherein the electrode rod is used for extending into a gas film hole of the air-cooled hollow blade and reserving a gap between the electrode rod and the inner wall of the gas film hole, an insulating layer is coated on the surface of the electrode rod except for a processing area corresponding to the gas film hole of the blade, and the conductive plate is arranged in the working liquid pool and used for being electrically connected with the air-cooled hollow blade. In the processing process, the scream in the gas film hole is contacted with fresh electrolyte, so that the metal dissolution speed at the position of the scream is far higher than that of other parts on the surface of the anode, and the scream can be quickly dissolved and removed.

Description

Air-cooled hollow blade air film hole inner wall sharp corner rounding device and method

Technical Field

The application belongs to the technical field of engine blade machining, and particularly relates to a device and a method for rounding sharp corners of inner walls of air-cooled hollow blade air film holes.

Background

With the increasing requirements of the aero-engine on the thrust-weight ratio, the temperature in front of the turbine of the engine is gradually increased, the temperature in front of the turbine of the new-generation aero-engine in the future is higher and higher, and the development speed of the high-temperature material and the thermal barrier coating at present is far from meeting the requirements of the advanced aero-engine. Therefore, advanced film cooling technology must be used to improve the temperature resistance of the turbine blade and achieve reliable operation for a long time. A plurality of mature air-cooled hollow blades are designed in China, dozens to hundreds of air film holes are distributed on the surfaces of the blades and are regularly arranged along the blade body direction, and the spatial position distribution is complex. In order to form a complete air film on the surface of the blade and achieve a good cooling effect, the included angle between the axis of each row of air film holes and the surface of the blade is very small, so that inclined hole air film holes (the holes with the axes being not vertical to the surface of the blade are called as cross holes) are formed, and the aperture of the inclined hole air film holes is generally between 0.2 mm and 0.8 mm. At present, the processing of the air film hole is mainly realized by adopting modes of laser, electric spark, electric liquid beam and the like.

For a turbine blade, the film holes, like artificially arranging a large number of "defects" on the blade substrate, can cause local stress concentration and reduce the fatigue resistance of the blade. The conventional inclined hole film hole of the blade forms sharp corners at one side of the hole edge, and the existence of the sharp corners seriously influences the service life of the turbine blade. The great engine faults caused by fatigue cracks at the sharp corners of the air film holes of the turbine blades occur to all the engines, so that economic property loss is caused. Therefore, a method for rounding the sharp corner of the blade gas film hole is needed to eliminate the sharp corner of the gas film hole, reduce or eliminate the local stress concentration at the edge of the blade gas film hole, and improve the fatigue resistance of the blade.

The sharp corner rounding of the gas film hole belongs to a positioning cutting deburring process. General part rounding is generally achieved by mechanical methods, magnetic grinding methods, abrasive flow methods, abrasive jet methods, chemical methods, electrochemical methods, and the like. The turbine blade is different from common parts, various molded surfaces are not allowed to be damaged or bruised in the rounding process of the air film hole, particularly, the structure of a cooling channel of an inner cavity of the blade is complex, and the sharp corner at the inner wall of the air film hole of the blade is very difficult to remove. At the present stage, the sharp angle rounding of the inner wall surface and the outer wall surface of the air film hole is generally realized by an abrasive particle flow method, but the abrasive particle flow removal efficiency is low, the problems of inner cavity cooling channel blockage or air film hole blockage and the like are easy to occur, and the preparation requirement of the hollow air-cooled blade of the advanced engine cannot be met. A plurality of patents about deburring of parts exist in China, but no method for rounding sharp corners of the inner surfaces of the gas film holes of the turbine blades is suitable.

The mechanical method is to remove the convex part by cutting or material surface shaping deformation to achieve the purpose of surface smoothness, and is the most widely applied method, and mainly comprises methods such as manual, tumbling, brushing, spraying and the like. Chinese patent publication No. 108620675a provides a machine part surface burr removing apparatus, which removes burrs on a part surface by a file, and blows off chips generated when air is driven by movement of a piston to remove burrs, thereby improving burr removing efficiency. The mechanical method is mainly used for parts with larger sizes, tools such as brushes and the like cannot enter the inner cavity of the hollow blade, no operation space exists, and sharp corners on the inner surface of the air film hole of the turbine blade cannot be removed; meanwhile, the mechanical method has poor control precision and is not suitable for precision machining of the blade.

The magnetic grinding method is characterized in that magnetized magnetic grinding materials are attracted together under the action of a magnetic field to form a magnetic grinding brush, the surface of a part is ground, and the magnetic grinding brush has good flexibility and adaptability. The Chinese patent with the publication number of 108581649A provides an efficient magnetic surface treatment method, and the method combines magnetic grinding and ultrasonic waves to enable a magnetic grinding material to generate pulse pressure on the surface of a part under the action of a magnetic field, so that the method is mainly used for the integral deburring of the surface of a workpiece, the surface of the workpiece is more compact and uniform, and the fatigue life of the workpiece is prolonged. The method can be used for the turbine guide blade with larger size and no complex cooling channel, the whole inner cavity of the blade is polished and the sharp angle of the air film hole is removed, but the rounding effect cannot be controlled. And for the turbine working blade with a complex inner cavity cooling channel structure and a narrow space, the method can not be realized. The grinding needle with an overlarge size can not be selected, so that the grinding needle is prevented from being difficult to take out and remaining in the inner cavity of the blade; and a grinding needle with an undersize size can not be selected, so that the magnetic needle is prevented from being drilled into a hole in the grinding process to cause blockage. And because the magnetic needle is limited by the space of the inner cavity of the blade, the movement range is small, the movement speed is low, the force generated when the magnetic needle collides with the surface of the inner cavity is small, and the removal effect is poor.

The abrasive flow method is to continuously grind the surface of a workpiece by the back and forth extrusion of abrasive particles and the flow of the abrasive particles to produce the functions of polishing and chamfering. At present, the abrasive flow method is mainly applied to remove the sharp corners on the surfaces of the inner cavities of the blades and the inner walls of the air film holes at home. Chinese patent publication No. 104999379a provides an abrasive flow micropore polishing apparatus, in which an ultrasonic vibrator is provided at the lower end of an abrasive flow passage of a pressurizing vibration base, and high acceleration energy is given to the abrasive flow by high-frequency vibration of the ultrasonic vibrator, thereby improving the processing efficiency and the quality of the processed surface. In the aspect of blade processing, an abrasive flow method mainly comprises the steps of deburring and polishing the whole inner cavity of the blade, and not only can be used for rounding the sharp corner of the air film hole, but also cannot be used for controlling the removal amount and rounding effect of the sharp corner because the abrasive flow method belongs to the whole processing technology and cannot consider the difference of the air film hole of the blade; secondly, the abrasive flow method has low processing efficiency; the size of the abrasive particles is not controlled well, the removal effect of the sharp corner of the air film hole is not good by selecting smaller abrasive particle flow particles, and the tiny air film hole is easy to block by larger abrasive particle flow particles; some substances contained in the abrasive particles can chemically react with the blade material, and have unknown influence on the blade.

The abrasive particle jet method is an upgrading version of the abrasive particle flow method, and improves the machining efficiency and the machining precision of the abrasive particle flow. The purpose of removing burrs is achieved by utilizing high-speed mixed flow of fine abrasive particles, solution medium and high-pressure gas to impact a workpiece. Chinese patent publication No. 105033870a provides a gas-liquid-solid three-phase abrasive flow supply device, which improves the mixing flow of abrasive flow, abrasive supply, and polishing performance. The method also has the problems of blocking the air film hole, generating chemical reaction with the blade substrate, being incapable of controlling the removal amount of the sharp corner of the air film hole, rounding effect and the like during the processing of the inner cavity of the blade.

The chemical polishing method is a method for eliminating grinding marks and etching and leveling by means of selective dissolution of a sample rugged region under the chemical etching action of a chemical reagent, and has the advantages of simple and convenient operation, low cost and the like, but the chemical polishing effect is inferior to that of electrochemical polishing. The invention discloses a method for removing burrs in machining of precision parts, which is disclosed by the invention of Chinese patent with the publication number of 101555601B. The parts are put into the prepared special chemical solution, are taken out after staying for a period of time at a certain temperature, and are washed and dried by running water, so that the aim of removing burrs at various positions such as the holes, the grooves, the ditches and the like of the parts can be fulfilled. Turbine blades are generally manufactured by adopting a casting process, and cast alloys have composition segregation, so that local corrosion is generated due to local potential difference. Chemical polishing is mainly used for stainless steel, copper alloy and the like, and is not suitable for casting high-temperature alloy.

In the traditional electrochemical polishing method, a polished workpiece is taken as an anode, insoluble metal is taken as a cathode, and in an electrolytic bath, direct current ionization reaction is carried out to generate anode dissolution, so that the effects of removing fine burrs on the surface of the workpiece and increasing the brightness are achieved. The machining process has no mechanical force and is suitable for complex parts. Chinese patent publication No. 109420810 provides an electrochemical deburring method for hard metals by adding an insulating layer between a non-burr region and a cathode head, spraying a treatment liquid to the burr region of a workpiece, and removing burrs by taking off reacted substances by the flow of the treatment liquid. The traditional electrochemical method is mainly applied to the aspects of deburring of large-size parts, improving the surface smoothness of the parts and the like, and is mainly applied to engine disks, shafts, titanium alloy blades and the like in the machining of the engine parts.

In conclusion, the existing sharp corner rounding of the gas film hole has the following defects:

1. the mechanical method is mainly used for parts with larger sizes, tools such as brushes and the like cannot enter the inner cavity of the hollow blade, no operation space exists, and sharp corners on the inner surface of the blade air film hole cannot be removed; meanwhile, the mechanical method has poor control precision and is not suitable for precision machining of the blade.

2. The magnetic grinding method can be used for turbine guide blades with large sizes and without complex cooling channels, the whole inner cavity of the blade is polished and the sharp angle of an air film hole is removed, but the rounding effect cannot be controlled. And for the turbine working blade with a complex inner cavity cooling channel structure and a narrow space, the method can not be realized. The grinding needle with an overlarge size can not be selected, so that the grinding needle is prevented from being difficult to take out and remaining in the inner cavity of the blade; and a grinding needle with an undersize size can not be selected, so that the magnetic needle is prevented from being drilled into a hole in the grinding process to cause blockage. And because the magnetic needle is limited by the space of the inner cavity of the blade, the movement range is small, the movement speed is low, the force generated when the magnetic needle collides with the surface of the inner cavity is small, and the removal effect is poor.

3. The abrasive particle flow method and the abrasive particle injection method mainly carry out deburring and polishing on the whole inner cavity of the blade, and not only carry out rounding on the sharp angle of the air film hole, but also cannot consider the difference of the air film hole of the blade and cannot control the removal amount and rounding effect of the sharp angle because the abrasive particle flow method belongs to the whole treatment process; the size of the abrasive particles is not controlled well, the removal effect of the sharp corner of the air film hole is not good by selecting smaller abrasive particle flow particles, and the tiny air film hole is easy to block by larger abrasive particle flow particles; additives used in abrasive flow processes contain substances that chemically react with the blade material and have an unknown effect on the blade.

4. The chemical method is mainly used for stainless steel, copper alloy and the like, and the polishing effect is inferior to that of electrochemical polishing. Turbine blades are generally manufactured by adopting a casting process, and cast alloys have composition segregation, so that local corrosion is generated due to local potential difference.

5. The traditional electrochemical method is mainly applied to the aspects of deburring of relatively large stainless steel parts, improving the surface smoothness of the parts and the like, and is applied to the processing of parts such as engine disks, shafts, titanium alloy blades and the like.

Disclosure of Invention

In order to solve at least one of the technical problems, the application provides a device and a method for rounding the sharp corner of the inner wall of the air-cooled hollow blade air film hole, wherein the sharp corner of the inner wall of the air-cooled hollow blade air film hole is rounded by adopting a pulse electrochemical method, and the purpose of rounding is achieved by carrying out local anodic dissolution by utilizing electric energy and chemical energy.

The application provides a first aspect provides a hollow blade air film hole inner wall closed angle radius device of air cooling, includes:

the electrolyte circulation module comprises an electrolyte tank and a working liquid tank arranged on the mobile platform, electrolyte is introduced to the upper part of the working liquid tank from the electrolyte tank through an injection pipe and flows back to the electrolyte tank from the working liquid tank through a return pipe, wherein the air-cooled hollow blade is positioned in the working liquid tank, and a nozzle of the injection pipe is aligned to a gas film hole of the air-cooled hollow blade;

the power supply loop comprises a power supply, an electrode rod led out from one pole of the power supply and a conductive plate led out from the other pole of the power supply, wherein the electrode rod is used for extending into a gas film hole of the air-cooled hollow blade and reserving a gap between the electrode rod and the inner wall of the gas film hole, an insulating layer is coated on the surface of the electrode rod except for a processing area corresponding to the gas film hole of the blade, and the conductive plate is arranged in a working liquid pool and used for being electrically connected with the air-cooled hollow blade.

Preferably, the power supply adopts a pulse power supply, the voltage of the pulse power supply is set to be 8-20V, and the pulse frequency is set to be 5000 Hz-10000 Hz.

Preferably, the moving platform is provided on a platform shelf and its movement is controlled by a control system.

Preferably, the conductive plate is fixed on a sample stage in the working fluid cell, and the sample stage is controlled to incline by the control system.

Preferably, the electrolyte comprises 10-25% of sodium nitrate and 5-10% of sodium citrate.

Preferably, the electrode rod is a Cu-W/Cu electrode.

Preferably, the diameter of the electrode rod is set to be 1/4-3/4 of the pore diameter of the air film hole.

Preferably, the insulating layer is an epoxy resin insulating layer.

Preferably, the electrode rod is clamped by an electrode clamp, the electrode clamp is fixed on an electrode platform, and the electrode platform is fixed on the moving platform and is adjustable in height relative to the moving platform.

Preferably, the conductive plate is a graphite conductive plate.

Preferably, the graphite conducting plate is connected with the positive electrode of the power supply, and the electrode rod is connected with the negative electrode of the power supply.

Preferably, the working liquid pool material is phenolic resin and is in the shape of a cuboid with an opening at the upper end.

Preferably, the sample stage and the conductive plate are fixed by bolts.

Preferably, the blade is pressed against the conductive plate via the end face of the tenon.

The second aspect of the present application provides a method for rounding the sharp angle of the inner wall of the air-cooled hollow blade air film hole, wherein the method for rounding the sharp angle of the inner wall of the air-cooled hollow blade air film hole is performed by using the apparatus as described above, and the method comprises the following steps:

circulating the electrolyte in the electrolyte circulation module;

adjusting the position and the angle of the air-cooled hollow blade to enable the electrode rod to vertically extend into the air film hole, aligning the working part of the electrode rod to the sharp corner of the inner wall of the air film hole and keeping a certain machining gap;

and setting parameters of a processing power supply and processing time, starting the power supply, and rounding the sharp corner of the inner wall of the gas film hole.

Preferably, after the work is finished, the ultrasonic cleaning of the blade is further carried out.

Preferably, the machining gap is about 0.05mm to 0.1mm, and the machining time is 10 to 100 seconds.

According to the invention, the sharp corner of the inner wall of each inclined hole gas film hole of the turbine blade is subjected to targeted rounding, so that the rounding effect of the sharp corner of each gas film hole is ensured, stress concentration caused by the sharp corner of the gas film hole of the turbine blade is eliminated, and the service life of the turbine blade is prolonged; the provided device and the operation method thereof are not influenced by the cooling channel of the inner cavity of the blade, and the rounding of the appointed position of the blade air film hole can be realized; the processing precision and the fillet surface quality are ensured by setting parameters such as pulse voltage, processing distance, processing time and the like; abrasive flow is not needed in the operation process, and the adverse effects of hole plugging, chemical reaction with blade materials and the like on the fatigue performance of the blade in the conventional method are eliminated. The invention has the advantages of simple and convenient operation, high stability, safety, reliability and the like.

Drawings

FIG. 1 is a schematic structural diagram of a sharp corner rounding device of a blade air film hole.

FIG. 2 is a schematic view of the relative position of the blade and the electrode.

The device comprises a power supply 1, an electrode rod 2, an air-cooled hollow blade 3, a conductive plate 4, a sample stage 5, a working liquid tank 6, an electrolyte tank 7, electrolyte 8, a pressure pump 9, a control system 10, a platform frame 11, a movable platform 12, an electrode platform 13 and an electrode clamp 14;

21-epoxy resin insulation, 31-blade outer surface, 32-blade inner surface.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application, and should not be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application. Embodiments of the present application will be described in detail below with reference to the drawings.

In a first aspect of the present application, a device for rounding a sharp corner of an inner wall of an air film hole of an air-cooled hollow blade, as shown in fig. 1 and 2, mainly includes:

the electrolyte circulating module comprises an electrolyte tank 7 and a working solution pool 6 arranged on a moving platform 12, wherein electrolyte 8 is introduced to the upper part of the working solution pool 6 from the electrolyte tank 7 through an injection pipe and flows back to the electrolyte tank 7 from the working solution pool 6 through a return pipe, the air-cooled hollow blade 3 is positioned in the working solution pool 6, and a nozzle of the injection pipe is aligned to an air film hole of the air-cooled hollow blade 3;

the power supply loop comprises a power supply 1, an electrode rod 2 led out from one pole of the power supply 1 and a conductive plate 4 led out from the other pole of the power supply 1, wherein the electrode rod 2 is used for extending into a gas film hole of the air-cooled hollow blade 3 and reserving a gap between the electrode rod 2 and the inner wall of the gas film hole, an insulating layer is coated on the surface of the electrode rod 2 except for a processing area corresponding to the gas film hole of the blade, and the conductive plate 4 is arranged in a working liquid pool 6 and used for being electrically connected with the air-cooled hollow blade 3.

According to the method, the pulse electrochemical method is adopted to carry out sharp-angle rounding on the air film hole of the air-cooled hollow blade, mechanical cutting force does not exist in the pulse electrochemical method in the machining process, additional stress and a surface deterioration layer cannot be formed, and the method is the preferred scheme of rounding machining. The working principle of pulse electrochemical sharp corner rounding is as follows: the method mainly utilizes electric energy and chemical energy to carry out local anodic dissolution to achieve the purpose of rounding. When in processing, the blade is connected with the positive pole of a direct current power supply, namely the positive pole; the Cu-W/Cu electrode is connected with the negative pole of a direct current power supply and is called a cathode. As shown in FIG. 2, the Cu-W/Cu electrode extends into the inner cavity of the blade from the outer surface 31 of the blade to one end of the inner surface 32 of the blade through the film hole, the action area of the electrode rod is aligned with the sharp corner part of the inner wall of the turbine blade, a proper processing gap is kept between the two parts so as to lead the circulating electrolyte to pass smoothly, the electrolysis products and heat generated in the processing process are flushed away from the processing area, and the processing area of the electrode surface except the processing area is coated with the epoxy resin insulating layer. During processing, the anode is dissolved: macroscopically, the sharp corner part of the inner wall of the blade air film hole is closer to the Cu-W/Cu electrode, the current density is high, and the sharp corner part is dissolved and forms a radius; microcosmically, the thickness of an oxide film at the wave crest position on the surface of the sharp corner part is smaller than that at the wave trough position, the metal dissolution speed at the wave crest position is greater than that at the wave trough position, so that the surface is gradually leveled, the sharp corner is finally rapidly dissolved and removed, a high-quality air film hole without the sharp corner on the inner wall is obtained, the stress concentration caused by the sharp corner of the air film hole of the blade is eliminated, and the service life of the turbine blade is prolonged. The method can also be applied to the hole edge rounding of the micro cross holes of other parts, and the service life of the parts is prolonged.

In some optional embodiments, the power supply 1 adopts a pulse power supply, the voltage of the pulse power supply is set to be 8-20V, and the pulse frequency is set to be 5000 Hz-10000 Hz.

In some alternative embodiments, the moving platform 12 is disposed on the platform shelf 11 and its movement is controlled by a control system.

In some alternative embodiments, the conductive plate 4 is fixed on a sample stage 5 in the working fluid pool 6, and the sample stage 5 is controlled to be inclined by the control system.

As shown in fig. 1, the moving platform 12 is connected to the platform frame 11 through a support, the platform frame 11 is controlled by the control system 10, the moving platform 12 is driven to move left and right/back and forth, the sample stage 5 is connected to the platform frame 11 through the connecting mechanism, the sample stage is controlled by the control system 10, and one end of the connecting mechanism, which is connected to the sample stage 5, is driven by deflection to realize the tilting function through the sample stage 5.

In this application, realize the accurate positioning in blade air film hole through the precision motor, realize the electrochemical machining to different angle air film holes, control system 10 can control platform's removal and slope through meticulous motor device: the moving platform can move forwards, backwards, leftwards, rightwards, upwards and downwards in six directions, and the moving distance is 10-20 cm; the inclined platform can control the processed blade to incline leftwards and rightwards, the inclination angle is-30-60 degrees, and all angle adjustments are accurately controlled by computer software.

In some optional embodiments, the electrolyte comprises 10-25% sodium nitrate and 5-10% sodium citrate. The working temperature of the electrolyte is 20-25 ℃.

In some alternative embodiments, the electrode rod 2 is a Cu-W/Cu electrode.

In some alternative embodiments, the electrode diameter is determined by the size of the gas film hole, and the diameter of the electrode rod 2 is generally set to be 1/4-3/4 of the diameter of the gas film hole.

In some alternative embodiments, the insulating layer is an epoxy insulating layer 21.

In some alternative embodiments, the electrode rod 2 is held by an electrode holder 14, the electrode holder 14 is fixed on an electrode platform 13, and the electrode platform 13 is fixed on the moving platform 12 and is adjustable in height relative to the moving platform 12.

In some alternative embodiments, the conductive plate is a graphite conductive plate, the graphite conductive plate is connected with the positive electrode of the power supply, and the electrode bar is connected with the negative electrode of the power supply; the working liquid pool is made of phenolic resin, is in the shape of a cuboid with an opening at the upper end, and is 30-50 cm long, 15-50 cm wide and 10-30 cm high. The sample stage and the conductive plate are fixed by bolts. The blade is connected on the current-conducting plate through the tenon terminal surface compresses tightly.

firstly, assembling each instrument respectively for standby;

secondly, the positive pole of the pulse power supply is connected with the anode conductive plate, and the negative pole of the pulse power supply is connected with the cathode electrode;

preparing mixed electrolyte of sodium nitrate and sodium citrate;

opening the pressure pump 9 to enable the electrolyte to enter the working solution pool to form a continuously circulating electrolyte system, and aligning the circulating liquid pouring head to the processed air film hole;

adjusting the working platform and the inclined platform to enable the cathode electrode to vertically extend into the blade air film hole, aligning the working part of the electrode with the sharp corner of the inner wall, and keeping a certain machining gap between the working part and the inner wall;

setting processing power supply parameters and processing time, and rounding the sharp corner of the inner wall of the blade;

seventhly, after the work is finished, the power supply is turned off, the blades are taken out, and ultrasonic cleaning and drying are carried out;

the sample stage can realize six-direction movement and angle inclination, the full-angle accessibility of the blade is realized, the working direction of the electrode is fixed, and the vertical lifting can be realized.

The processing clearance is about 0.05 mm-0.1 mm, the processing time is 10-100 s, and the processing time is determined according to the material type.

The device and the method have the advantages of simple operation, safety, high efficiency, strong practicability and the like, can realize the accurate positioning and rounding of the sharp angle of the inner wall of the gas film hole of the inclined hole of the turbine blade without stress, obtain the gas film hole without the sharp angle and with high quality, eliminate the stress concentration caused by the sharp angle of the gas film hole of the blade and prolong the service life of the turbine blade.

The device and the method are not influenced by the cooling channel of the inner cavity of the blade, and can realize the blade processing of the cooling channel with small space and complex inner cavity.

The device and the method use a small processing gap and a high-frequency current effect through a pulse electrochemical method, so that the electrolyte is updated more quickly, the problem that processing heat is not easy to remove is solved, and the processing precision and the fillet surface quality are ensured.

The device and the method do not need abrasive flow, and adverse effects on the fatigue performance of the blade, such as hole plugging, chemical reaction with the blade material and the like in the conventional method, are avoided.

The device and the method can accurately position the test, round the fixed point, avoid the problem of processing the surface which does not need to be processed, have no mechanical cutting force in the processing process and can not generate additional stress.

The device realizes semi-automatic operation, and easy operation realizes processing quality control through parameters such as regulation and control voltage, processing distance and process time.

The device and the method adopt neutral inorganic salt electrolyte to replace the traditional acid electrolyte, and have small corrosion and small environmental pollution.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a hollow blade air film hole inner wall closed angle radius device of air cooling which characterized in that includes:

the electrolyte circulating module comprises an electrolyte tank (7) and a working liquid pool (6) arranged on the mobile platform (12), electrolyte is introduced to the upper part of the working liquid pool (6) from the electrolyte tank (7) through an injection pipe and flows back to the electrolyte tank (7) from the working liquid pool (6) through a return pipe, wherein the air-cooled hollow blade (3) is positioned in the working liquid pool (6), and a nozzle of the injection pipe is aligned to an air film hole of the air-cooled hollow blade (3);

the power supply loop comprises a power supply (1), an electrode rod (2) led out from one pole of the power supply (1) and a conductive plate (4) led out from the other pole of the power supply (1), wherein the electrode rod (2) is used for extending into a gas film hole of the air-cooled hollow blade (3) and reserving a gap between the electrode rod and the inner wall of the gas film hole, an insulating layer is coated on the surface of the electrode rod (2) except for a processing area corresponding to the gas film hole of the blade, and the conductive plate (4) is arranged in a working liquid pool (6) and used for being electrically connected with the air-cooled hollow blade (3).

2. The air-cooled hollow blade air film hole inner wall sharp corner rounding device according to claim 1, wherein a pulse power supply is adopted as the power supply (1), the voltage of the pulse power supply is set to be 8-20V, and the pulse frequency is set to be 5000 Hz-10000 Hz.

3. The air-cooled hollow blade gas film hole inner wall sharp corner rounding device according to claim 1, wherein the moving platform (12) is provided on a platform frame (11) and its movement is controlled by a control system.

4. The air-cooled hollow blade gas hole inner wall sharp corner rounding device according to claim 3, wherein the conductive plate (4) is fixed to a sample stage (5) in the working fluid bath (6), and the inclination of the sample stage (5) is controlled by the control system.

5. The air-cooled hollow blade air film hole inner wall sharp corner rounding device according to claim 1, wherein the electrolyte comprises 10-25% of sodium nitrate and 5-10% of sodium citrate.

6. The air-cooled hollow blade gas film hole inner wall sharp corner rounding device according to claim 1, wherein the electrode bar (2) is a Cu-W/Cu electrode.

7. The air-cooled hollow blade gas film hole inner wall sharp corner rounding device according to claim 1, wherein the diameter of the electrode rod (2) is set to 1/4-3/4 of the diameter of the gas film hole.

8. The air-cooled hollow blade gas film hole inner wall sharp corner rounding device according to claim 1, wherein the insulating layer is an epoxy resin insulating layer (21).

9. The gas-cooled hollow blade gas film hole inner wall sharp corner rounding device according to claim 1, wherein the electrode rod (2) is clamped by an electrode clamp (14), the electrode clamp (14) is fixed on an electrode platform (13), and the electrode platform (13) is fixed on the moving platform (12) and is adjustable in height relative to the moving platform (12).

10. A method for rounding the sharp corner of the inner wall of a gas film hole of an air-cooled hollow blade, which is performed by using the apparatus according to any one of claims 1 to 9, the method comprising:

circulating the electrolyte in the electrolyte circulation module;

adjusting the position and the angle of the air-cooled hollow blade to enable the electrode rod (2) to vertically extend into the air film hole, aligning the working part of the electrode rod (2) to the sharp angle of the inner wall of the air film hole and keeping a certain machining gap;