CN102606502A

CN102606502A - Method for exciting and controlling gas flow of stator blade end wall of axial-flow compressor by aid of plasmas

Info

Publication number: CN102606502A
Application number: CN2012100370071A
Authority: CN
Inventors: 吴云; 李应红; 赵小虎; 李军; 贾敏
Original assignee: Air Force Engineering University of PLA
Current assignee: Air Force Engineering University of PLA
Priority date: 2012-02-19
Filing date: 2012-02-19
Publication date: 2012-07-25

Abstract

The invention relates to a method for using plasma excitation to control gas flow on the end wall of the stator vane of an axial flow compressor. The leading edge and trailing edge of the electrode are respectively flush with the leading edge and trailing edge of the stator blade, and the direction of the electrode is parallel to the middle arc of the stator blade; when the engine controller detects the sign of flow instability, a pulsed plasma power supply is used An electrical signal is applied to the electrodes of the plasma pneumatic actuator; when the engine controller detects that the sign of flow instability disappears, a control signal is sent to turn off the plasma pneumatic actuator. The control method proposed by the invention can effectively suppress the flow separation in the angular region of the stator vane of the axial flow compressor, and has short excitation response time and wide frequency band, which plays an important role in reducing the total pressure loss of the vane wake and improving the stability and efficiency of the compressor.

Description

Utilize the method for plasma excitation Control Shaft flow air compressor stator blade end wall gas flow

Technical field

The invention belongs to the active Flow Control technology in gas turbine engine field, relate to a kind of method of utilizing plasma excitation Control Shaft flow air compressor stator blade end wall gas flow, and the plasma pneumatic actuators that is used for this method.

Background technique

Axial flow compressor is one of core component of aviation gas turbine Duct-Burning Turbofan, and its development trend is higher pressure ratio, efficient and stability, progression still less.Because the strong pressure gradient of flow direction and the boundary layer lateral flow in the blade path, low energy fluid is gathered in stator blade suction surface/end wall angular region, and then forms significant angular region flow separation.The angular region is separated one side and is limited the raising that gas compressor is loaded and static pressure rises ability, causes the decline of compressor efficiency and stall margin on the other hand, and gives the interstage matched deleterious impact of multiatage axial flow compressor.Therefore, separate the angular region is one of key factor of restriction gas compressor pressure ratio, efficient and stability lifting, how to suppress the angular region and separate, and be challenging key issue in the design of high-performance gas compressor.

Passive flow control methods such as blade is curved plunders, end wall wing fence, can under typical operating conditions, effectively suppress the angular region separates, still, and because the working state excursion of gas compressor is wide, the very difficult adaptation of these methods different working condition.Adopting the active Flow Control method is an important development trend, and will be blended in the pneumatic design of gas compressor as a new degrees of freedom.Boundary layer blows/inhales is a kind of typical active Flow Control energisation mode of present broad research, is suppressing to have obtained good effect aspect the separation of angular region.But, owing to need the air-channel system of more complicated, very difficult generation fast, wide band excitation, will become a major obstacle that limits its development.

Summary of the invention

The technical problem that solves

For fear of the deficiency of existing technology, the present invention proposes a kind of method of utilizing plasma excitation Control Shaft flow air compressor stator blade end wall gas flow, and the plasma pneumatic actuators that is used for this method.Can solve that other flow control meanses can not solve or problem such as the insoluble excitation of control quickly, for realization real-time adaptive FLOW CONTROL provides the good basis condition.

Technological scheme

A kind of method of utilizing plasma excitation Control Shaft flow air compressor stator blade end wall gas flow is characterized in that step is following:

Step 1: lay the plasma pneumatic actuators in axial flow compressor stator blade passage end wall, the leading edge of plasma pneumatic actuators electrode is concordant with trailing edge with the leading edge of stator blade respectively with trailing edge, and the direction of electrode is parallel with the mean camber line of stator blade;

Step 2:, adopt the pulsed plasma power supply electrical signal to be loaded on the electrode of plasma pneumatic actuators when engine controller detects when flowing the unstability tendency; The output voltage waveforms of said electrical signal is sinusoidal wave, and voltage is between 1～30kV, and discharge frequency is between 1～40kHz, and pulse frequency is between 10-1000Hz, and dutycycle is between 1%-100%;

Step 3: when engine controller detects the unstability tendency that flows and disappears, send control signal, close the plasma pneumatic actuators.

A kind of plasma pneumatic actuators that is used for said method is characterized in that comprising upper surface electrode, lower surface electrode and insulating material; It is parallel on insulating material that to be provided with multi-group electrode right; Described electrode pair is on two surfaces of insulating material, to be provided with upper surface electrode and lower surface electrode, has separation delta d between two electrodes; During use, upper surface electrode connects with the pulsed plasma power supply, and lower surface electrode ground connection produces plasma at the upper surface electrode edge.

The thickness h of said upper surface electrode and lower surface electrode _eBe 0.018mm, width is 2mm.

Said insulation thickness h _dBe 0.5mm.

Said separation delta d is 1mm.

Said insulating material is a polyimide.

Said electrode material is a Copper Foil.

Beneficial effect

A kind of method of utilizing plasma excitation Control Shaft flow air compressor stator blade end wall gas flow that the present invention proposes, and the plasma pneumatic actuators that is used for this method.Plasma flow control is based on a kind of novel active Flow Control method of plasma air-operated drive; Utilize gaseous discharge to produce the controlled disturbance that stream field applies in the process of plasma; Change the speed and the vorticity boundary conditions in flow field; And then the realization FLOW CONTROL, suppressing to have remarkable technical advantage aspect the separation of angular region.

The controlling method that the present invention proposes can effectively suppress axial flow compressor stator blade angular region flow separation, and the exciter response time is short, Bandwidth, for reducing stator blade tail pitot loss, improves gas compressor stability and efficient and has important function.Tunnel test shows that end wall plasma air-operated drive can effectively suppress NACA 0065 compressor blade row angular region flow separation under the condition of speed of incoming flow 90m/s, with the maximum reduction by 13% of the blade wake passing pitot loss of 70% leaf eminence.The major advantage of this method is that excitation frequency band is wide, effect rapidly, do not have moving element, simple in structure, energy consumption is lower.

Description of drawings

Fig. 1: be the conceptual scheme that plasma air-operated drive electrode is arranged on axial flow compressor stator blade end wall;

The 1-blade inlet edge, 2-blade trailing edge, 3-end wall, 4-plasma excitation device, 5-plasma excitation device;

Fig. 2: the layout chart that is plasma air-operated drive electrode;

The 6-upper surface electrode, 7-lower surface electrode, 8-insulating material, A-plasma;

Fig. 3: the output waveform figure that is the pulsed plasma power supply;

Fig. 4: be the installation photo of compressor blade row on the tunnel test platform.

Embodiment

Combine embodiment, accompanying drawing that the present invention is further described at present:

Step 1: lay the plasma pneumatic actuators in axial flow compressor stator blade passage end wall, like the stator blade end wall position that marks among Fig. 1.The leading edge of plasma pneumatic actuators electrode is concordant with trailing edge with the leading edge of stator blade respectively with trailing edge, and the direction of electrode is parallel with the mean camber line of stator blade;

The electrodes use copper electrode of said plasma air-operated drive electrode separates with insulating material between electrode, and insulating material is a polyimide.The layout of plasma air-operated drive electrode is as shown in Figure 2, upper surface electrode width d ₁Be 2mm, lower surface electrode width d ₂Be 2mm, upper and lower surface electrode separation delta d is 1mm, upper and lower surface electrode thickness h _eBe 0.018mm, insulation thickness h _dBe 0.5mm.

The two ends of plasma air-operated drive electrode are respectively at linking to each other with grounding end with the high voltage terminal of pulsed plasma power supply.

Step 2:, adopt the pulsed plasma power supply electrical signal to be loaded on the electrode of plasma pneumatic actuators when engine controller detects when flowing the unstability tendency; The output voltage waveforms of said electrical signal is sinusoidal wave, and voltage is between 1～30kV, and discharge frequency is between 1～40kHz, and is as shown in Figure 3.Driving pulse repetition frequency f=1/T _Control, f=10～1000Hz; Driving pulse duty cycle alpha=T _Signal/ T _Control* 100%, α=1%～100%.

In the present embodiment, in the compressor blade row wind-tunnel quantitative appraisal pulsed plasma air-operated drive suppress the effect that separate the angular region, as shown in Figure 4.Under the condition of speed of incoming flow 90m/s; (energizing voltage is 10kV to the pulsed plasma air-operated drive; Pulse frequency is 600Hz, and dutycycle is 70%) effectively suppress NACA 0065 compressor blade row angular region flow separation, with the maximum reduction by 13% of the blade wake passing pitot loss of 70% leaf eminence.

Claims

1. A method utilizing plasma excitation to control the flow of gas at the end wall of an axial flow compressor vane is characterized in that the steps are as follows:

Step 1: Lay a plasma pneumatic exciter on the end wall of the stator vane channel of the axial flow compressor. The leading edge and trailing edge of the plasma pneumatic exciter electrode are respectively flush with the leading edge and trailing edge of the stator vane, and the direction of the electrode is the same as that of the stator blade. The middle arcs of the blades are parallel;

Step 2: When the engine controller detects the sign of flow instability, the pulse plasma power supply is used to load the electric signal on the electrode of the plasma pneumatic actuator; the output voltage waveform of the electric signal is a sine wave, and the voltage is 1-30kV Between, the discharge frequency is between 1-40kHz, the pulse frequency is between 10-1000Hz, and the duty cycle is between 1%-100%;

Step 3: When the engine controller detects that the sign of flow instability disappears, a control signal is sent to turn off the plasma pneumatic actuator.

2. A plasma pneumatic exciter for the method of claim 1 is characterized in that comprising an upper surface electrode, a lower surface electrode and an insulating material; on the insulating material, a plurality of groups of electrode pairs are arranged in parallel; said electrode On the two surfaces of the insulating material, an upper surface electrode and a lower surface electrode are provided, and there is a distance Δd between the two electrodes; when in use, the upper surface electrode is connected to the pulse plasma power supply, and the lower surface electrode is grounded. The plasma is generated at the edge of the surface electrode.

3. The plasma pneumatic actuator according to claim 2, characterized in that: the thickness h _e of the upper surface electrode and the lower surface electrode is 0.018mm, and the width is 2mm.

4. The plasma pneumatic actuator according to claim 2, characterized in that the thickness h _d of the insulating material is 0.5 mm.

5. The plasma pneumatic actuator according to claim 2, characterized in that: the distance Δd is 1 mm.

6. The plasma pneumatic actuator according to claim 2, characterized in that: the insulating material is polyimide.

7. The plasma pneumatic actuator according to claim 2, characterized in that: the electrode material is copper foil.