Fluidic oscillator application to control method of high load compressor corner flow separation

Abstract

The fluid oscillator is applied to the control method of high-load compressor corner area flow separation, and the structure of the fluid oscillator comprises an air inlet, a porous material, an intermediate transition section, a micro controllable valve, an inlet and an outlet, the air inlet is adjacent to the pressure surface side of the compressor blade, the porous material is connected with the air inlet, one end of the intermediate transition section is connected with the air inlet, the other end of the intermediate transition section is connected with the micro controllable valve, the micro controllable valve is connected with the inlet, the inlet is connected with the outlet, and the outlet is located on the end wall near the compressor cascade corner area. Compared with the traditional technology, the application does not need an external air source, has the advantages of simple structure, small volume and weight, long-term work reliability and strong engineering practicability. Through the method, the flow separation near the compressor corner area can be effectively inhibited, the single-stage compressor can obtain a higher pressure ratio, and the turbomachinery has a larger thrust-to-weight ratio and higher efficiency.

Description

Technical Field

[0001] This invention relates to the field of compressor flow control, and more specifically to a control method for using a fluid oscillator to control flow separation in the corner region of a high-load compressor. Background Technology

[0002] Axial compressors are crucial components of aero-turbojet engines and gas turbines, and their performance directly impacts the efficiency and stability of these engines. The continuous pursuit of higher thrust-to-weight ratios in engines, especially aero-engines, necessitates further increases in compressor stage pressure ratios. This leads to excessively high compressor stage loads, resulting in highly complex internal flow. For example, strong adverse pressure gradients within the stator cause flow separation in the endwall and suction regions. Severe flow separation not only causes channel blockage and reduced aerodynamic efficiency but can also lead to rotating stall and surge. To further increase compressor stage load, it is necessary to overcome problems such as intensified flow separation in the stator endwall and suction regions and insufficient diffusion capacity caused by increased load. Therefore, suppressing flow separation within high-load compressors is critical. One feasible method is to introduce flow control in high-load compressors. Flow separation control methods can be divided into passive control methods, which mainly use slotted blades, vortex generators, and wing fences, and active control methods, which mainly use boundary layer jetting, boundary layer suction, pulse jets, synthetic jets, and plasma excitation, depending on whether external energy is introduced.

[0003] The advantage of passive flow control methods lies in their relatively low requirements for the material properties of compressor components. However, since the flow control principle is based on energy redistribution, improvements in certain performance indicators at some locations often lead to performance degradation at other locations, thus requiring comprehensive consideration. Active flow control methods typically achieve higher aerodynamic performance indicators and offer a wider variety and range of adjustable parameters. However, the need for additional energy input complicates the compressor structure. For example, for pulsed jets, a high-pressure air source and a periodically opening and closing valve are usually required to provide energy and generate unsteadiness. Flow control technology can be divided into steady control and unsteady control. The difference between steady and unsteady flow control methods is that the latter involves periodic excitation, affecting the unsteady coherent structure in the flow field. Unsteady flow control methods are more effective than steady flow control methods, generally requiring less energy input to achieve the same control effect. Unsteady flow control is usually implemented using active flow control technology.

[0004] Traditional active unsteady flow control typically suffers from several problems that limit its engineering applications.

[0005] 1. Traditional active flow control methods generally require an external energy supply, such as the introduction of air or electricity. Given the limited installation space inside an aircraft compressor, it is difficult to integrate the flow control actuator with external air or power into a complex air or electrical system. This significantly increases the complexity of the compressor structure, making it unsuitable for practical engineering applications.

[0006] 2. Traditional unsteady flow control methods typically involve complex actuator structures, often containing moving parts. For example, pulse jet and pulse suction require valves that open and close periodically at a controllable frequency to produce periodic jets and suction. The valve opening and closing actions are usually generated by electrical devices such as solenoid valves. This unsteady control mode, relying on periodic valve opening and closing, has two drawbacks: firstly, frequent valve opening and closing accelerates the damage to valves and related electrical devices, significantly increasing the compressor failure rate; secondly, existing technologies such as solenoid valves struggle to achieve ultra-high frequency opening and closing, making it difficult to maximize the unsteady control effect, resulting in low engineering practicality and reliability.

[0007] 3. Traditional flow control technologies generally cannot autonomously adjust when controlling compressor flow separation, and often require external input signals for control, meaning they lack adaptability. For example, when the compressor is operating unstable or its operating conditions change significantly, external input control is difficult to respond to in a timely manner, resulting in unsatisfactory control performance.

[0008] Therefore, a smart flow control method using a self-excited adaptive fluid oscillator to suppress flow separation in high-load compressors is proposed to solve the above-mentioned technical problems. Summary of the Invention

[0009] The purpose of this invention is to provide a control method for applying a fluid oscillator to flow separation in the corner region of a high-load compressor, so as to overcome the above-mentioned shortcomings and deficiencies of the prior art.

[0010] A fluid oscillator includes: an air intake, a porous material, an intermediate transition section, a miniature controllable valve, an inlet, and an outlet. The air intake is adjacent to the pressure surface side of a compressor blade. The porous material is connected to the air intake. One end of the intermediate transition section is connected to the air intake. The other end of the intermediate transition section is connected to the miniature controllable valve. The miniature controllable valve is connected to the inlet. The inlet is connected to the outlet. The outlet is located on the end wall near the corner region of the compressor blade.

[0011] Furthermore, the fluid oscillator is self-excited, and the compressor used in the fluid oscillator is a high-load compressor or a compressor with large flow separation.

[0012] Furthermore, the air intake is located on the side wall of the pressure surface in the middle of the blade.

[0013] Furthermore, the air intake is located on the side wall of the pressure surface at the leading edge of the blade.

[0014] Furthermore, the air intake is located on the side wall of the pressure surface at the leading edge of the adjacent blade.

[0015] Furthermore, the scanning plane of the outlet is located in the circumferential direction.

[0016] Furthermore, the scanning plane of the outlet is located in the axial direction.

[0017] Furthermore, the angle between the scanning plane of the outlet and the axial direction is 45°.

[0018] Furthermore, the angle between the scanning plane of the outlet and the vertical direction is 15° to 45°.

[0019] A fluid oscillator is used in a control method for flow separation in the corner region of a high-load compressor, and the method is implemented through the following steps:

[0020] Step 1: During the operation of the compressor, a pressure difference will be formed on both sides of the blades, with the pressure on the pressure side being greater than the pressure on the suction side.

[0021] Step 2: High-pressure gas on the pressure side passes through the porous material and enters the improved fluid oscillator vent.

[0022] Step 3: The gas passes through the intermediate transition section and reaches the miniature controllable valve;

[0023] Step 4: Manually set the opening degree of the miniature controllable valve as needed;

[0024] Step 5: The airflow passes through a miniature controllable valve and enters the inlet of the fluid oscillator;

[0025] Step 6: After the gas enters the fluid oscillator, it forms a periodic swept jet at the outlet;

[0026] Step 7: The swept jet formed from the outlet of the fluid oscillator blows away and energizes the low-energy fluid accumulated on the suction side of the compressor blades, reducing the accumulation of low-energy fluid in the corner region, thereby reducing the separation in the corner region of the compressor blades, reducing losses, and improving efficiency.

[0027] The beneficial effects of this invention are:

[0028] Compared with traditional technologies, this invention does not require an external air source, has a simple structure, small size and weight, and is reliable in long-term operation, making it highly practical for engineering applications. This method effectively suppresses airflow separation near the compressor corner region, allowing single-stage compressors to achieve a higher pressure ratio, thus enabling turbomachinery to have a greater thrust-to-weight ratio and higher efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a fluid oscillator.

[0030] Figure 2 This is a schematic diagram of the circumferential arrangement of the fluid oscillator.

[0031] Figure 3 This is a schematic diagram of the axial arrangement of the fluid oscillator.

[0032] Figure 4 This is a schematic diagram of air ducting at the front end of the fluid oscillator end wall.

[0033] Figure 5 This is a schematic diagram of the external shape of the Coanda swept oscillator.

[0034] Figure 6 There are four different configurations of fluid oscillators.

[0035] Figure 7 This is a schematic diagram of the present invention.

[0036] Figure 8 This is a schematic diagram of the location of the air intake in Example 1.

[0037] Figure 9 This is a schematic diagram of the outlet location in Example 1.

[0038] Figure 10 This is a schematic diagram of the location of the air intake in Example 2.

[0039] Figure 11 This is a schematic diagram of the location of the air intake in Example 3.

[0040] Figure 12 This is a schematic diagram of the outlet location in Example 4.

[0041] Figure 13 This is a schematic diagram of the outlet location in Example 5.

[0042] Figure 14 This is a schematic diagram of the outlet location in Example 6.

[0043] Figure label:

[0044] Air intake port 100, porous material 200, intermediate transition section 300, miniature controllable valve 400, inlet 500 and outlet 600. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] Example 1

[0047] Figure 1This is a schematic diagram of a fluid oscillator. Figure 2 This is a schematic diagram of the circumferential arrangement of the fluid oscillator. Figure 3 This is a schematic diagram of the axial arrangement of the fluid oscillator. Figure 4 This is a schematic diagram of air ducting at the front end of the fluid oscillator end wall. Figure 5 This is a schematic diagram of the external shape of the Coanda swept oscillator. Figure 6 There are four different configurations of fluid oscillators. Figure 7 This is a schematic diagram of the present invention. Figure 8 This is a schematic diagram of the location of the air intake in Example 1. Figure 9 This is a schematic diagram of the outlet location in Example 1. Figure 10 This is a schematic diagram of the location of the air intake in Example 2. Figure 11 This is a schematic diagram of the location of the air intake in Example 3. Figure 12 This is a schematic diagram of the outlet location in Example 4. Figure 13 This is a schematic diagram of the outlet location in Example 5. Figure 14 This is a schematic diagram of the outlet location in Example 6.

[0048] like Figure 1 As shown in Figure 4, a fluid oscillator includes: an air intake 100, a porous material 200, an intermediate transition section 300, a miniature controllable valve 400, an inlet 500, and an outlet 600. The air intake 100 is adjacent to the pressure surface side of the compressor blade. The porous material 200 is connected to the air intake 100. One end of the intermediate transition section 300 is connected to the air intake 100, and the other end of the intermediate transition section 300 is connected to the miniature controllable valve 400. The miniature controllable valve 400 is connected to the inlet 500, and the inlet 500 is connected to the outlet 600. The outlet 600 is located on the end wall near the corner region of the compressor blade.

[0049] The fluid oscillator is self-excited, and the compressor used in the fluid oscillator is a high-load compressor or a compressor with large flow separation.

[0050] The air intake 100 is located on the side wall of the pressure surface in the middle of the blade.

[0051] The scanning plane at exit 600 is located in the circumferential direction.

[0052] A fluid oscillator is applied to a control method for flow separation in the corner region of a high-load compressor. The method is implemented through the following steps:

[0053] Step 1: During the operation of the compressor, a pressure difference will be formed on both sides of the blades, with the pressure on the pressure side being greater than the pressure on the suction side.

[0054] Step 2: High-pressure gas on the pressure side passes through the porous material and enters the improved fluid oscillator vent.

[0055] Step 3: The gas passes through the intermediate transition section and reaches the miniature controllable valve;

[0056] Step 4: Manually set the opening degree of the miniature controllable valve as needed;

[0057] Step 5: The airflow passes through a miniature controllable valve and enters the inlet of the fluid oscillator;

[0058] Step 6: After the gas enters the fluid oscillator, it forms a periodic swept jet at the outlet;

[0059] Step 7: The swept jet formed from the outlet of the fluid oscillator blows away and energizes the low-energy fluid accumulated on the suction side of the compressor blades, thereby reducing the separation in the compressor blade corner region, reducing losses, and improving efficiency.

[0060] The purpose of this invention is to enable single-stage compressors to achieve higher pressure ratios, thereby increasing the thrust-to-weight ratio and efficiency of turbomachinery. A smart flow control method based on a fluid oscillator is proposed to suppress flow separation in high-load compressors. This method effectively suppresses airflow separation near the compressor endwalls and blade suction surfaces.

[0061] Its structure includes: an air intake 100, a porous material 200, an intermediate transition section 300, a miniature controllable valve 400, an inlet 500, and an outlet 600. Under the action of the pressure difference on both sides of the blade, the gas passes through the air intake 100, and after passing through the intermediate transition section 300, it finally forms a pulse jet or sweeping jet with a certain frequency and pressure on the suction surface of the blade, thereby weakening or even eliminating the airflow separation near the compressor endwall and the suction surface of the blade.

[0062] like Figure 7-9 As shown, the specific location of the fluid oscillator outlet depends on the performance of the selected compressor blade, including circumferential and axial arrangements, and the number of arrangements is variable. In this embodiment, only a single fluid oscillator is arranged, and the sweeping plane of outlet 600 is located in the circumferential direction, so the fluid oscillator sweeps in the circumferential direction. The fluid at the outlet of the fluid oscillator will form a swept jet in the circumferential direction, and the fluid in the diagonal region will form a circumferential excitation, which can effectively blow away the low-energy fluid accumulated on the endwall in the circumferential direction, and the excitation range is relatively wide. In this embodiment, the air intake 100 is located on the side endwall of the pressure surface in the middle of the blade. The incoming flow velocity is high at the leading edge of the blade, and air is drawn from the middle. There is a relatively large pressure difference between the air intake and the two sides of the fluid oscillator, and the flow channel is short, resulting in small friction loss.

[0063] The porous material 200, installed at the air inlet 100 of the self-excited fluid oscillator, not only improves the strength and rigidity of the compressor end wall but also minimizes the influence of the air inlet 100 on the aerodynamic shape of the end wall surface. Furthermore, the addition of the porous material 200 prevents large particulate impurities from entering the transition section, avoiding the risk of blockage. The miniature controllable valve 400 is located between the intermediate transition sections. Since the miniature controllable valve is prior art and its structure is common knowledge in the field, its structure is not claimed in the claims. This system includes miniature electromagnets, miniature strong magnets, miniature gates, and wires. The miniature strong magnets are fixed to the miniature gates, and the miniature electromagnets are fixed to the inlet wall of the self-excited fluid oscillator. When the miniature electromagnets are energized, they become strongly magnetic. When different electrical signals are input to the miniature electromagnets, the magnetic poles generated by the miniature electromagnets are not in the same direction. By utilizing the principle that like poles of magnets repel and unlike poles attract, the opening and closing of the miniature gates can be achieved, thereby controlling the speed and pressure of the gas entering the self-excited fluid oscillator. This results in jets of different frequencies and pressures being generated at the outlet of the self-excited fluid oscillator, thus reducing blade corner separation.

[0064] The fluid oscillator relies on the Coanda effect of the jet. After the main jet stabilizes, it adheres to the side wall, and some of the fluid passes through the feedback channel and eventually acts on the main jet again, causing it to oscillate.

[0065] like Figure 5 As shown, Figure 5 This is a Coanda swept fluid oscillator. After the fluid enters the oscillator, due to the Coanda effect, the fluid flows close to one side of the Coanda surface. Assuming the fluid flows close to the upper wall, most of the fluid will flow downwards through the throat and out of the ejector, while a feedback fluid forms in the upper feedback channel. This feedback fluid flows to the starting position of the jet, pushing the jet direction towards the opposite Coanda surface. At this point, most of the fluid flows upwards through the throat and out of the ejector, forming feedback fluid in the lower feedback channel. This process repeats, and the flow at the outlet exhibits a swept flow pattern with a certain period.

[0066] The miniature controllable valve 400 is located in the intermediate transition section 300 and coupled to the compressor end wall. When bleed gas is required, the opening and closing of the miniature controllable valve 400 and the degree of opening are controlled as needed to control the gas velocity and pressure entering the self-excited fluid oscillator, thereby generating oscillating jets of different frequencies and pressures at the outlet 600 of the self-excited fluid oscillator to reduce blade corner separation.

[0067] During compressor operation, the gas pressure near the blade pressure surface is greater than that near the suction surface, creating a pressure difference across the blades. Under this pressure difference, the gas permeates the porous material and enters the intermediate flow channel coupled to the end wall through the air inlet. When the micro-valve is open, gas enters the inlet 500 of the fluid oscillator through the valve. At this time, the gas pressure is still greater than the outlet pressure of the fluid oscillator, causing the gas to spontaneously pass through the oscillator and form a pulsed jet or sweeping jet at the outlet. The frequency and velocity of the jet are related to the pressure and velocity of the incoming gas.

[0068] The innovation of this invention lies in utilizing a fluid oscillator to achieve control during the flow separation process in a high-load compressor. Through the self-excitation of the fluid oscillator, fully automated operation is achieved. To achieve this, the fluid oscillator itself has been improved. To allow air to be drawn from the blade pressure side to the oscillator inlet, the original oscillator was modified by adding an intermediate transition section and an air inlet. Furthermore, a micro-valve was added to the intermediate transition section, enabling active control of the gas flow rate entering the fluid oscillator, thereby achieving controllability of the jet frequency and velocity at the oscillator outlet. The end of the air inlet is made of a porous material to prevent large particles from entering the transition section and avoid the risk of blockage.

[0069] like Figure 6 As shown, the specific principle requires an introduction to the classification of fluid oscillators, which can be divided into two categories: pulse jet oscillators and swept jet oscillators. Based on the different principles controlling the jet oscillation process, fluid oscillators can be further divided into relaxation-type oscillators, acoustic oscillators, Coanda swept oscillators, and jet-coupled oscillators. Relaxation-type, acoustic, and Coanda swept oscillators all have only one inlet main jet. Their working principle relies on the Coanda effect of the jet; after the main jet stabilizes, it adheres to the sidewall, and some fluid, through the feedback channel, ultimately acts on the main jet again, causing it to oscillate. Jet-coupled oscillators, on the other hand, have two inlet jets. These two jets undergo a complex coupling and mixing process within the coupling cavity, forming an oscillating jet at a single outlet.

[0070] Relaxation-type and acoustic-type oscillators have two outlets. Under steady-state inlet conditions, each outlet forms a pulsed oscillating jet along the outlet channel direction, meaning the jet direction remains unchanged while its velocity changes periodically.

[0071] Coanda swept-type and jet-coupled oscillators have only one outlet. Under steady-state inlet conditions, the absolute value of the velocity of the main flow at the outlet does not change, but its direction oscillates at a certain frequency within a certain angle range, forming a swept-type oscillating jet. The internal flow self-excited deflection process of a typical Coanda swept-type fluid oscillator is as follows: it has two feedback channels. The fluid enters in an upward direction. Due to the Coanda effect, the main flow flows against the baffle wall. Due to the flow restriction effect of the outlet nozzle, part of the fluid flows back into the feedback channel to the control throat, filling the separation bubble and causing the separation bubble to grow continuously, thereby pushing the main flow to the other feedback channel. This cycle repeats, forming a swept-type oscillating jet at the nozzle. The fluid oscillator of this invention relies on the Coanda effect of the jet. After the main jet stabilizes, it adheres to the side wall, and part of the fluid passes through the feedback channel and finally acts on the main jet again, causing it to oscillate.

[0072] In the existing technology, there is a numerical study on the influence of frequency sweep jet on the flow separation of compressor blades under design conditions, Propulsion Technology, 2020, No.273(03):91-98. (EI indexed, retrieval number: 20201508389221), and the third chapter of the dissertation of Dr. Meng Qinghe on the mechanism of unsteady jet control of axial compressor blade corner separation. There are cases where fluid oscillators have been used in compressor blades, but the application scenarios are different. The author placed the fluid oscillator in the middle of the blade, and the inlet was connected to the air pump through a pipe to draw air from the outside.

[0073] This method has certain drawbacks. The driving force required for the fluid oscillator jet in this method comes from an external supply, necessitating an external air pump to provide energy. This not only consumes external energy but also increases the likelihood of malfunctions due to the need for an external air evacuation device, making it unsuitable for engineering applications. In contrast, this invention uses a self-excited fluid oscillator, which is self-driven by the pressure difference across the blade endwalls.

[0074] Secondly, the outlet of the fluid oscillator in the above method is arranged on the blade surface. The swept jet formed at the outlet can only reach a limited range and has little impact on the flow field of the blade cascade. It can mainly only blow away the low-energy fluid on the blade surface, but cannot play a role in the large amount of low-energy fluid on the boundary layer on the endwall.

[0075] In addition to the above, in the paper "Concept of Self-Excited Unsteady Flow Control on a Compressor Blade and its Preliminary Proof by Numerical Simulation[J].Aerospace Science and Technology, 123: 107498," the authors used the pressure difference between the two sides of the blade surface to drive the flow. Although this method does not require an external air source, the fluid oscillator outlet is also located on the blade surface in this paper, which has the same drawbacks as the aforementioned literature, namely a small range of influence and limited control effect.

[0076] This invention is placed within the endwall of the blade cascade, utilizing the pressure difference between the endwalls on both sides of the blade as the driving force. The endwall arrangement is flexible and varied; it can be positioned close to the blade, in the middle of the flow channel, or across the blade, drawing air from the pressure side of other blades, or from the leading edge of the blade. The outlet arrangement of the fluid oscillator is also highly variable. When arranged axially only against the blade surface, it effectively removes the boundary layer from the blade surface; when arranged circumferentially and obliquely downstream only against the endwall, it effectively removes the boundary layer on the endwall; when sweeping obliquely downwards circumferentially, it removes the boundary layer from both the blade surface and the endwall, effectively suppressing separation in the blade cascade corner region.

[0077] More importantly, if the outlet is oriented axially and sweeps towards the pressure side of the blade, the present invention can also suppress the migration of the endwall boundary layer, hinder the development of horseshoe vortices towards the suction surface, thereby effectively suppressing the development of secondary flow, which is an effect that cannot be achieved by arranging it on the blade surface.

[0078] Furthermore, the improved fluid oscillator of this invention incorporates a miniature control valve in the intermediate transition section, allowing for free control of its opening degree. This regulates the fluid entering the oscillator and controls the sweeping frequency and speed at the outlet. Compared to existing fluid oscillator control methods, this invention offers advantages such as controllable outlet performance and a wider range of influence.

[0079] Example 2

[0080] like Figure 10 As shown, in this embodiment, the air intake 100 is located on the side wall of the pressure surface at the leading edge of the blade. The incoming flow velocity at the leading edge of the blade is high; drawing air from the leading edge allows the fluid entering the fluid oscillator to have a higher velocity, thus forming a jet with a higher excitation frequency at the fluid oscillator outlet. The rest is the same as in Embodiment 1.

[0081] Example 3

[0082] like Figure 11As shown, in this embodiment, the air intake 100 is located on the side wall of the pressure surface at the leading edge of the adjacent blade. There is no better effect, but the position can be adjusted according to the specific project requirements, providing more options during the adjustment process. The rest is the same as in Embodiment 1.

[0083] Example 4

[0084] like Figure 12 As shown, in this embodiment, the sweeping plane of outlet 600 is located in the axial direction. The fluid at the outlet of the fluid oscillator forms a swept jet in the axial direction, and the fluid in the diagonal region forms an axial excitation, which can effectively blow away the low-energy fluid accumulated on the end wall near the blade. At the same time, when the fluid oscillator is close to the blade, it is beneficial to blow away the low-energy fluid in the boundary layer on the blade surface. The rest is the same as in Embodiment 1.

[0085] Example 5

[0086] like Figure 13 As shown, in this embodiment, the sweeping plane of outlet 600 forms a 45° angle with the axial direction. The fluid at the outlet of the fluid oscillator forms a swept jet in a direction at a 45° angle with the axial direction. The fluid in the diagonal region forms an excitation in a direction at a 45° angle with the axial direction, which can affect the low-energy fluid accumulated on the end wall in the circumferential direction and the low-energy fluid near the blades on the end wall. The rest is the same as in Embodiment 1.

[0087] Example 6

[0088] like Figure 14 As shown, in this embodiment, the angle between the sweeping plane of outlet 600 and the vertical direction is 15° to 45°. The fluid at the outlet of the fluid oscillator forms a swept jet in a direction with an angle of 15° to 45° to the vertical direction. The fluid in the diagonal region is excited in a direction with an angle of 15° to 45° to the vertical direction, and the low-energy fluid in the diagonal region plays a role in blowing away and energizing it. The rest is the same as in Embodiment 1.

[0089] Compared with traditional technologies, this invention does not require an external gas source and has the advantages of simple structure, small size and weight.

[0090] It is reliable in long-term operation and has strong engineering applicability. This method can effectively suppress airflow separation near the compressor corner region, allowing single-stage compressors to achieve a higher pressure ratio, thereby enabling turbomachinery to have a larger thrust-to-weight ratio and higher efficiency.

[0091] The specific embodiments of the present invention have been described above, but the present invention is not limited thereto. Various changes can be made to the present invention as long as they do not depart from the spirit of the present invention.

Claims

1. A fluid oscillator, characterized in that, include: The compressor comprises an air intake (100), a porous material (200), an intermediate transition section (300), a miniature controllable valve (400), an inlet (500), and an outlet (600). The air intake (100) is adjacent to the pressure surface side of the compressor blade. The porous material (200) is connected to the air intake (100). One end of the intermediate transition section (300) is connected to the air intake (100), and the other end of the intermediate transition section (300) is connected to the miniature controllable valve (400). The miniature controllable valve (400) is connected to the inlet (500). The inlet (500) is connected to the outlet (600), and the outlet (600) is located on the end wall near the corner region of the compressor blade.

2. A fluid oscillator according to claim 1, characterized in that: The fluid oscillator is self-excited, and the compressor used in the fluid oscillator is a high-load compressor or a compressor with large flow separation.

3. A fluid oscillator according to claim 1, characterized in that: The air intake (100) is located on the side wall of the pressure surface in the middle of the blade.

4. A fluid oscillator according to claim 1, characterized in that: The air intake (100) is located on the side wall of the pressure surface at the leading edge of the blade.

5. A fluid oscillator according to claim 1, characterized in that: The air intake (100) is located on the side wall of the pressure surface at the leading edge of the adjacent blade.

6. A fluid oscillator according to claim 1, characterized in that: The scanning plane of the outlet (600) is located in the circumferential direction.

7. A fluid oscillator according to claim 1, characterized in that: The scanning plane of the outlet (600) is located in the axial direction.

8. A fluid oscillator according to claim 1, characterized in that: The angle between the scanning plane of the outlet (600) and the axial direction is 45°.

9. A fluid oscillator according to claim 1, characterized in that: The angle between the scanning plane of the outlet (600) and the vertical direction is 15° to 45°.

10. A control method for flow separation in the corner region of a high-load compressor using a fluid oscillator, characterized in that: The method is implemented through the following steps: Step 1: During the operation of the compressor, a pressure difference will be formed on both sides of the blades, with the pressure on the pressure side being greater than the pressure on the suction side. Step 2: High-pressure gas on the pressure side passes through the porous material and enters the improved fluid oscillator vent. Step 3: The gas passes through the intermediate transition section and reaches the miniature controllable valve; Step 4: Manually set the opening degree of the miniature controllable valve as needed; Step 5: The airflow passes through the miniature controllable valve and enters the inlet of the fluid oscillator; Step 6: After the gas enters the fluid oscillator, it forms a periodic swept jet at the outlet; Step 7: The swept jet formed from the outlet of the fluid oscillator blows away and energizes the low-energy fluid accumulated on the suction side of the compressor blades, reducing the accumulation of low-energy fluid in the corner region, thereby reducing the separation in the corner region of the compressor blades, reducing losses, and improving efficiency.

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