A device and method for liquid particle flow boiling finishing of turbine blade air cooling channel

Abstract

A device and method for liquid-particle flow boiling finishing of turbine blade air-cooling channels is characterized in that the device includes an abrasive liquid tank, an infusion pump, an infusion pipeline, a damper, a blade fixture, a control computer, an agitator, a liquid tank heater, a liquid tank insulation layer, a liquid tank temperature sensor, a pipeline temperature sensor, a pipeline heater, a pipeline insulation layer, and a tongue-and-groove heater. The working fluid is preheated to a set temperature in the abrasive liquid tank by the liquid tank heater, pressurized by the infusion pump, and delivered to the infusion pipeline. It is then further heated to boiling point by the pipeline heater and delivered to the turbine blade air inlet via the blade fixture. The tongue-and-groove heater continuously heats the metal turbine blade, maintaining the working fluid's boiling state within the blade cavity and generating a large number of tiny bubbles, forming a gas-liquid-particle three-phase flow. This allows efficient finishing of the channel walls and air film holes along the flow path of the turbine blade air-cooling channel. The process of the present invention is simple, efficient, safe, and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to a finishing technology for complex inner cavities of parts, in particular to a liquid particle flow boiling finishing device and method, specifically to a liquid particle flow boiling finishing device and method for turbine blade air cooling channels. Background Art

[0002] Turbine blades are critical components in turbofan and turboshaft engines. To improve thermal cycle efficiency and thrust-to-weight ratio, the temperature of the gas flowing upstream of the turbine continues to rise, increasing the thermal load on the turbine blades. This requires efficient cooling through internal air-cooling channels within the blades. Turbine blades are fabricated from difficult-to-machine high-temperature alloys. Their air-cooling channels consist of multi-curved internal flow channels, dense film cooling holes (film holes), and exhaust slots along the trailing edge. During operation, cooling air enters through the blade's groove inlet, flows through the internal flow channels, and cools the blade substrate along its length. It is then discharged through the film holes and exhaust slots along the trailing edge, forming an air film to protect the blade surface. Turbine blades are subjected to a combination of severe loads during operation, including high temperatures, vibration, and centrifugal forces. The surface quality of the air-cooling channels is crucial for blade cooling efficiency and fatigue life. However, due to the limited accessibility of turbine blade air-cooling channels, surface finishing is extremely challenging.

[0003] Turbine blade exteriors and internal flow channels are currently produced using high-temperature alloy investment casting. The air film holes on the blade surface are machined through one by one using specialized energy field manufacturing methods such as electrospark, electrohydraulic beam, or laser. The surface roughness of the blade's internal flow channels formed by investment casting or additive manufacturing is high, resulting in increased pressure loss along the cooling airflow. Film holes machined using thermal processes such as electrospark can have a remelted layer on the surface, which can cause fatigue cracks and lead to blade failure. Sharp edges exist at the intersection of the internal flow channel and the film hole (at the film hole entrance), which can affect the smoothness of the cooling air film outflow and reduce cooling efficiency. Therefore, before turbine blades enter service, the air cooling channels must be finished to improve surface quality, remove the remelted layer on the film hole walls, and eliminate sharp edges. Currently, abrasive flow machining is used for finishing turbine blade air cooling channels. However, due to the high viscosity and poor fluidity of the abrasive flow machining medium, it is difficult to remove residual machining medium from the internal cavity.

[0004] Liquid particle flow machining uses a low-concentration, water-based abrasive liquid as the working medium. As the liquid flows at high speed over the workpiece, the fine abrasive particles in the liquid micro-cut the workpiece surface, completing the polishing process. Liquid particle flow machining offers advantages such as good working medium fluidity, excellent accessibility to complex cavities, and easy removal of residual medium, making it an ideal technique for finishing turbine blade air-cooling channels. The process is as follows: the abrasive liquid is pumped into the blade through the bottom air inlet of the blade groove. As it flows, it first finishes the inner channel wall. It then exits through the film holes and trailing edge exhaust slots, efficiently finishing the entire film cooling channel. However, in practical applications of liquid particle flow finishing of turbine blade air-cooling channels, it has been found that when the abrasive liquid flows at high speed in the channel, the large flow resistance of the solid wall causes the abrasive particles to tend to aggregate toward the center of the channel. This results in a smaller distribution of abrasive particles near the wall, inefficient wall material removal, and poor blunting of the sharp edges at the film hole entrances.

[0005] In the liquid particle flow finishing processing of the blade air-cooling channel, the present invention proposes to heat the abrasive liquid to a boiling state, forcing the liquid phase to vaporize and generate more bubbles. The bubbles continuously migrate, aggregate, and burst under the thrust of the high-flow abrasive liquid, causing violent turbulence in the flow field, prompting the divergent distribution of the abrasive particles, and enhancing the impact kinetic energy and action density of the abrasive particles on the wall and sharp edges, thereby improving the wall material removal efficiency and strengthening the blunting effect of the sharp edges at the entrance of the air film hole. Summary of the Invention

[0006] The purpose of the present invention is to design a liquid particle flow boiling finishing processing device to address the problems of low finishing efficiency, difficulty in removing processing media, and poor blunting effect of sharp edges at the entrance of air film holes in existing aircraft engine turbine blades, and at the same time provide a corresponding method, by which the air cooling channels of turbine blades can be quickly finished.

[0007] One of the technical solutions of the present invention is:

[0008] A device for liquid-particle flow boiling finishing of turbine blade air-cooling channels includes an abrasive liquid tank, a tank heater, a tank insulation layer, a working fluid agitator, a working fluid temperature sensor, an infusion pump, a damper, an infusion pipeline, a pipeline heater, a pipeline insulation layer, a pipeline temperature sensor, a blade fixture, a tongue-and-groove heater, a blade body temperature sensor, a blade tip temperature sensor, a turbine blade, and a control computer. The abrasive liquid tank stores a low-concentration water-based abrasive working fluid. The agitator and tank temperature sensor are mounted within the abrasive liquid tank. The tank heater and tank insulation layer are wrapped around the exterior of the abrasive liquid tank, and the infusion pump is connected to the abrasive liquid tank. The pipeline temperature sensor, pipeline heater, and pipeline insulation layer are positioned outside the infusion pipeline. The turbine blade is mounted on a blade fixture, which is equipped with a tongue-and-groove heater, a blade body temperature sensor, and a blade tip temperature sensor. The infusion pipeline is connected to the turbine blade air inlet through the blade fixture and sealed. The computer is respectively connected to the agitator, liquid tank heater, liquid tank temperature sensor, infusion pump, pipe heater, pipe temperature sensor, tongue and groove heater, blade body temperature sensor, and blade tip temperature sensor. The computer collects temperature signals of the above temperature sensors in real time and controls the working status of the liquid tank heater, pipe heater, and tongue and groove heater in real time.

[0009] During operation, the working fluid is mixed uniformly in the abrasive tank by an agitator, then preheated to the set temperature by a tank heater. The fluid is then pressurized by an infusion pump and fed into the infusion pipeline. A damper stabilizes the pressure, and the fluid is further heated to boiling point by a pipeline heater before being fed into the turbine blade inlet via a blade fixture. A tongue-and-groove heater heats the metal turbine blades and maintains the blade body temperature within a set range. The working fluid generates numerous bubbles during boiling, forming a three-phase flow of gas, liquid, and particles. As the fluid flows through the turbine blade's air-cooling channel, it finishes the channel walls and film holes along the way, ultimately discharging through the blade film holes.

[0010] When the device is working, the computer monitors the liquid tank temperature sensor, the pipe temperature sensor, the blade body temperature sensor, and the blade tip temperature sensor in real time, and controls the liquid tank heater, the pipe heater, and the tongue and groove heater accordingly to ensure that the working fluid flowing in the inner cavity of the turbine blade is in a boiling state.

[0011] Technical solution 2 of the present invention:

[0012] A method for liquid particle flow boiling finishing of an air cooling channel of a turbine blade comprises the following steps:

[0013] 1. Determine the liquid particle flow polishing processing parameters, including: abrasive size, abrasive concentration, liquid supply pressure, polishing time, and configure the working fluid;

[0014] 2. Install the turbine blade on the blade fixture. Connect the tongue and groove heater on the blade fixture to the blade tongue and groove. Connect the blade air inlet to the liquid infusion pipe through the fixture and seal it.

[0015] 3. Determine the temperature control parameters, including the liquid tank heating temperature, the pipe heating temperature, and the blade heating temperature. First, start the liquid tank heater to heat the working fluid to the set temperature. Then, start the pipe heater and the tongue and groove heater to heat the liquid delivery pipe and blades to the set temperature.

[0016] 4. Start the infusion pump to pressurize the working fluid into the delivery pipe, and finally enter the turbine blade air cooling channel through the blade air inlet;

[0017] 5. The control computer monitors the liquid tank temperature sensor, pipe temperature sensor, blade body temperature sensor, and blade tip temperature sensor in real time, and controls the liquid tank heater, pipe heater, and tongue and groove heater accordingly to ensure that the working fluid flowing in the inner cavity of the turbine blade is in a boiling state.

[0018] 6. After the processing reaches the set time, the infusion pump, working fluid heater, pipeline heater and tongue and groove heater stop working, and the processed blade parts are taken out.

[0019] The beneficial effects of the present invention are:

[0020] Compared with the normal temperature liquid particle flow finishing of turbine blades, heating the abrasive liquid to a boiling state can force the liquid phase to vaporize and generate more bubbles. The bubbles continuously migrate, aggregate, and rupture under the thrust of the high-velocity abrasive liquid, causing violent turbulence in the flow field, prompting the divergent distribution of abrasive particles, and enhancing the impact kinetic energy and action density of abrasive particles on the wall and sharp edges, thereby improving the wall material removal efficiency and strengthening the blunting effect of the sharp edge at the entrance of the air film hole.

[0021] For different turbine blade models, the air-cooling channel finishing process can be achieved on the above-mentioned device simply by replacing the corresponding blade fixture, thus reducing costs. Furthermore, the present invention's preheating of the working fluid tank, along-line heating of the fluid delivery pipeline, and blade groove heating and temperature control scheme ensure uniform heating of the abrasive working fluid, maintaining a boiling state as it flows through the turbine blade's internal channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the device of the present invention.

[0023] Figure 2 This is a schematic diagram of the normal temperature liquid particle flow finishing processing of the turbine blade air cooling channel.

[0024] Figure 3 This is a schematic diagram of the liquid particle flow boiling finishing process in the air cooling channel of the turbine blade.

[0025] Figure: 1. Working fluid tank, 2. Tank heater, 3. Tank insulation, 4. Agitator, 5. Tank temperature sensor, 6. Infusion pump, 7. Damper, 8. Infusion pipeline, 9. Pipe heater, 10. Pipe insulation, 11. Pipe temperature sensor, 12. Blade fixture, 13. Tongue-and-groove heater, 14. Blade body temperature sensor, 15. Blade tip temperature sensor, 16. Turbine blade, 17. Control computer. 16.1 Blade inlet, 16.2. Bubbles, 16.3 Abrasive particles, 16.4 Film holes, 16.5. Inlet angle, 16.6. Bubble burst, 16.7. Turbulence DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example

[0027] like Figure 1 、 2 , as shown in 3.

[0028] A device for liquid particle flow boiling finishing of an air-cooling channel of a turbine blade comprises an abrasive liquid tank 1, a liquid tank heater 2, a liquid tank insulation layer 3, a liquid tank temperature sensor 5, a working liquid agitator 4, an infusion pump 6, a damper 7, an infusion pipeline 8, a pipeline heater 9, a pipeline insulation layer 10, a pipeline temperature sensor 11, a turbine blade 16, a blade fixture 12, a tongue and groove heater 13, a blade body temperature sensor 14, a blade tip temperature sensor 15, and a control computer 17, which are arranged in sequence. Figure 1 As shown. The blade clamps can be designed and manufactured by themselves, or they can be directly used by machining clamps with appropriate improvements. For those skilled in the art, designing the corresponding clamps does not require creative work, so the present invention will not be described in detail. Figure 1As shown, the abrasive liquid tank 1 stores a low-concentration water-based abrasive working fluid. The agitator 4 and tank temperature sensor 5 are installed in the abrasive liquid tank 1. The tank heater 2 and tank insulation layer 3 are wrapped around the outside of the abrasive liquid tank. The infusion pump 6 is connected to the abrasive liquid tank 1. The pipeline temperature sensor 11, pipeline heater 9, and pipeline insulation layer 10 are arranged outside the infusion pipeline. The turbine blade 16 is mounted on the blade fixture 12, which is equipped with a tongue-and-groove heater 13, a blade body temperature sensor 14, and a blade tip temperature sensor 15. The infusion pipeline 8 is connected to the turbine blade air inlet 16.1 through the blade fixture 12 and is sealed. The computer is connected to the agitator 4, tank heater 2, tank temperature sensor 5, infusion pump 6, pipeline heater 9, pipeline temperature sensor 11, tongue-and-groove heater 13, blade body temperature sensor 14, and blade tip temperature sensor 15. The computer involved in the invention is a conventional computer, and the control software installed therein can be developed by relevant technicians without creative effort and can be customized directly from the market if necessary. Computer 17 monitors the tank temperature sensor 5, pipe temperature sensor 11, blade body temperature sensor 14, and blade tip temperature sensor 15 in real time, and controls the tank heater 2, pipe heater 9, and tongue-and-groove heater 13 accordingly to ensure that the working fluid flowing within the turbine blade cavity is in a boiling state. During conventional liquid particle flow finishing of the turbine blade air-cooling channel, abrasive particles 16.3 primarily accumulate in the flow channel center, resulting in a smaller distribution of abrasive particles near the wall surface. However, during abrasive liquid boiling finishing, the boiling of the abrasive liquid generates a large number of bubbles 16.2. The bubble collapse 16.6 and intense turbulence 16.7 promote the distribution of abrasive particles close to the wall surface, enhancing the blunting effect of the sharp corner 16.5 of the air film hole entrance. Example

[0029] like Figure 1 、 2 , as shown in 3.

[0030] A method for liquid particle flow boiling finishing of an air cooling channel of a turbine blade. In this embodiment, the turbine blade is made of a high-temperature alloy, the abrasive is garnet micropowder, and the blade fixture is made of stainless steel.

[0031] In this embodiment, the diameter of the film hole of the turbine blade is 0.3-0.5 mm;

[0032] In this embodiment, the processing time is obtained through experiments according to different blade models; the liquid tank heating set temperature, the pipe heating set temperature and the blade body heating set temperature are obtained through experiments according to different blade models;

[0033] The specific steps are as follows:

[0034] 1. Determine the liquid particle flow polishing process parameters. The specific parameters are as follows: abrasive particle size 10-15μm, abrasive concentration 1%, liquid supply pressure 3MPa, and polishing time can be determined through experiments. Then prepare the working fluid.

[0035] 2. Install the turbine blade on the blade fixture. Connect the tongue and groove heater on the blade fixture to the blade tongue and groove. Connect the blade air inlet to the liquid infusion pipe through the fixture and seal it.

[0036] 3. Determine the temperature control parameters as follows: the abrasive liquid temperature in the liquid tank is set to 90°C, and the abrasive liquid temperature is heated to 100°C along the pipeline. The blade tongue and groove heating is mainly used to maintain the blade body temperature at the boiling point of the abrasive liquid, thereby maintaining the abrasive liquid in the blade cavity at a reasonable boiling state; the tongue and groove heater can be controlled on and off based on the data from the blade body temperature sensor and the blade tip temperature sensor. First, start the liquid tank heater to heat the abrasive liquid to 90°C, then start the pipeline heater and tongue and groove heater to heat the liquid delivery pipeline and blades to the set temperature;

[0037] 4. Start the infusion pump to pressurize the working fluid into the delivery pipeline, and finally enter the turbine blade air cooling channel through the blade air inlet;

[0038] 5. The control computer monitors the liquid tank temperature sensor, pipeline temperature sensor, blade body temperature sensor, and blade tip temperature sensor in real time, and controls the on and off of the liquid tank heater, pipeline heater, and tongue and groove heater accordingly to ensure that the working fluid flowing in the inner cavity of the turbine blade is in a boiling state. In the boiling state, bubbles will be generated in the liquid particle flow. Under the action of bubbles and turbulence, the abrasive particles will actively flow to the inner flow channel wall through the squeezing and impact of the bubbles, and the inner surface will be finished through the comprehensive effects of impact, friction, etc., such as Figure 3 As shown in Figure 2. The flow state of abrasive particles in the blade cavity at room temperature is as follows: Figure 2 As shown, its collision contact with the channel wall is significantly smaller than Figure 3 The collision condition between the abrasive particles in the boiling liquid of the present invention and the flow channel wall is shown.

[0039] 6. After the processing reaches the set time, the infusion pump, working fluid heater, pipeline heater and tongue and groove heater stop working, and the processed blade parts are taken out.

[0040] The specific embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection of the claims of the present invention.

[0041] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

Claims

1. A device for liquid-particle flow boiling finishing of a turbine blade air-cooling channel, comprising: An abrasive liquid tank (1), an infusion pump (6), an infusion pipe (8), a damper (7), a blade fixture (12), and a control computer (17); the abrasive liquid tank (1) is provided with a stirrer (4), a liquid tank heater (2), and a liquid tank insulation layer (3); the abrasive liquid tank (1) is also provided with a liquid tank temperature sensor (5); a plurality of pipe temperature sensors (11) are provided on the infusion pipe (8), the outer layer of which is wrapped with a pipe heater (9), and the outer surface of the pipe heater (9) is wrapped with a pipe insulation layer (10); the turbine blade (16) is fixed by a blade fixture (12), and a tongue-and-groove heater (13) is provided on the blade fixture (12); the infusion pipe (8) is connected to the turbine blade air inlet (16.1) through the blade fixture; a blade body temperature sensor (14) and a blade tip temperature sensor (15) are installed on the blade; the abrasive liquid tank (1) stores The low-concentration water-based abrasive working fluid, the infusion pipe (8) is connected to the abrasive liquid tank (1), the infusion pump (6), the damper (7), and the blade fixture (12) in sequence; the working fluid is mixed uniformly in the abrasive liquid tank (1) by the stirrer (4), and then preheated to the set temperature by the liquid tank heater (2), pressurized by the infusion pump (6) and sent to the infusion pipe (8), the damper (7) performs pressure stabilization, and then continues to be heated to the boiling point by the pipe heater (9), and then sent to the turbine blade air inlet (16.1) through the blade fixture (12); the tongue and groove heater (13) heats the metal turbine blade and keeps the blade body temperature within the set range; the working fluid generates a large number of bubbles during the boiling process, forming a gas-liquid-particle three-phase flow, and performs finishing processing on the channel wall and air film hole along the flow process in the inner cavity channel of the turbine blade, and finally discharges from the blade air film hole.

2. The device according to claim 1, further characterized in that: The control computer (17) is respectively connected to the agitator (4), the liquid tank heater (2), the liquid tank temperature sensor (5), the infusion pump (6), the pipe heater (9), the pipe temperature sensor (11), the tongue and groove heater (13), the blade body temperature sensor (14), and the blade tip temperature sensor (15). The control computer (17) collects temperature signals from the above-mentioned temperature sensors in real time and controls the working states of the liquid tank heater (2), the pipe heater (9), and the tongue and groove heater (13) in real time.

3. A processing method based on the liquid particle flow boiling finishing processing device for the air cooling channel of a turbine blade according to claim 1, characterized in that By heating the liquid particle flow to boiling and keeping it in a boiling state while flowing through the flow channel inside the blade, the boiling of the working fluid will form a large number of tiny bubbles, forming a gas-liquid-particle three-phase flow, and efficiently finishing the wall surface of the blade cavity channel and the wall surface of the air film hole, and blunting the sharp corners of the air film hole entrance.

4. The method according to claim 3, wherein The following steps are involved: Step 1: Determine the liquid particle flow polishing process parameters, including abrasive size, abrasive concentration, liquid supply pressure, polishing time, and configure the working fluid; Step 2: Mount the turbine blade (16) on the blade fixture (12), connect the tongue and groove heater (13) on the blade fixture (12) to the blade tongue and groove, and connect the blade air inlet (16.1) to the liquid delivery pipe through the fixture (12) and seal it; Step 3, determining temperature control parameters, including: liquid tank heating temperature, pipe heating temperature and blade heating temperature; first starting the liquid tank heater (2) to heat the working fluid to the set temperature, then starting the pipe heater (9) and the tongue and groove heater (13) to heat the liquid delivery pipe and the blade to the set temperature; Step 4: Start the infusion pump (6) to pump the working fluid into the delivery pipe (8) under pressure, and finally enter the turbine blade air cooling channel through the blade air inlet (16.1); Step 5, the control computer (17) monitors the liquid tank temperature sensor (5), the pipe temperature sensor (11), the blade body temperature sensor (14), and the blade tip temperature sensor (15) in real time, and controls the liquid tank heater (2), the pipe heater (9), and the tongue and groove heater (13) accordingly, to ensure that the working fluid flowing in the inner cavity of the turbine blade is in a boiling state; the boiling of the working fluid will form a large number of tiny bubbles, forming a gas-liquid-particle three-phase flow, and the wall surface of the blade inner cavity channel and the wall surface of the air film hole are efficiently finished, and the sharp corner of the air film hole entrance is blunted; Step 6: After the processing reaches the set time, the infusion pump (6), the liquid tank heater (2), the pipe heater (9) and the tongue and groove heater (13) stop working, and the processed blade parts are taken out.

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