EP2268925B1 - Gas turbine compressor - Google Patents

Description

The invention relates to a gas turbine compressor with a compressor housing, guide vanes, blades, valve-controlled injection ports for stabilizing the compressor flow and a plurality of valves for controlling the amount of air blown through the injection ports, wherein a plurality of coupled with the control of the valves sensors distributed in the region of the blades on the circumference of the flow channel are.

Compressors may start pumping under certain operating conditions (throttle condition). Typically, the pumping results from an unstable flow condition. This condition can preferably occur in the partial load range (off-design state). The compressor of gas turbines is designed for certain flight conditions in which it must provide the pre-calculated characteristics such as throughput, pressure ratio, efficiency, etc. But even beyond these design points, the compressor still has acceptable and safe operating characteristics, e.g. in the landing approach of an aircraft, where fast thrust changes and thus fast speed changes are required for adherence to a glide path. But even when starting in the lower speed range of the compressor to ensure proper flow and must allow a quick start up to full load.

Of course, the compressor map is also measured in the partial load range. To determine a safe operating range, the so-called driving line, the operating points on different speed lines interconnected, have a sufficient safety margin to the so-called surge limit, in which, as I said, a stall takes place on the compressor blades.

Already in the past there were attempts to shift the surge limit as far as possible to low throughputs in order to bring the driving line into other areas or to be able to fix it even further away from the surge limit.

Solutions in the prior art are, in particular, the injection of air into the housing or rotor region of a compressor under certain operating conditions. By this lateral injection of air in the direction of blades to the flow in the compressor be stabilized. The injection of air can be stationary (without changing the Einblasmassenstroms) or controlled by means of valves, the latter in the DE 10 2005 052 466 A1 and the US 6,125,626 is described.

The document US-A-5 340 271 relates to a gas turbine compressor with valve-controlled injection ports for stabilizing the compressor flow. The control of the valves is coupled to sensors in the region of the blades, wherein a plurality of sensors are arranged distributed on the circumference of the flow channel. The sensors are designed as a flow rate detecting hot wire sensors. The document refers to a state of the art in which pressures are converted into control signals.

The object of the invention, in contrast, is to make the stabilization of the flow by blowing in the area of the blades even more effective and precise.

For this purpose, the gas turbine compressor according to the invention of the aforementioned type provides that a plurality of pressure sensors distributed on the circumference of the flow channel are arranged upstream and downstream of the injection openings. By providing a plurality of pressure sensors distributed on the circumference of the flow channel upstream and downstream of the injection openings, the pressures can be determined before and after introduction of the additional air, which is even more effective and permits even more precise regulation or control.

The injection ports should be located immediately upstream of the blades.

Since there are flow states during pumping, in which modular peripheral disturbances occur, it is advantageous to associate each injection opening with its own valve.

Of course, several injection ports may also have one of numerous valves, to save components and costs.

The numerous valves assigned to the injection openings allow continuous, modulated or pulsed flows to be achieved.

Modular peripheral disorders can be eradicated by targeted anti-phase injection as in the case of anti-sounding. Of course, even brief, peak-like disturbances can be effectively remedied by a quick, complete opening of one or more valves.

The valve or valves are microvalves, in particular based on MEMS technology.

Such valves are characterized by a fast switchability and usually have an external actuator, which can also modulate / oscillate the valve (for example, with 400 Hz).

The control of the pressure sensors can be integrated in the respective pressure sensor itself, so that a pressure sensor is assigned to one or more valves and controls them directly, or a central control can be provided.

The actuators are in particular magnetic coils or piezo elements.

The valves and the injection openings are located in particular in the outer housing, but also an inflow in the hub area is alternatively possible.

The invention further provides a method for stabilizing the gas turbine compressor flow by means of an electrical control coupled to a plurality of valves provided at the periphery of the flow passage at inflow ports. The inventive method provides that the pressure conditions determined in the flow channel and depending on the valves are controlled. This determination is made directly via the pressure sensors.

The pressure conditions are detected in particular upstream and / or downstream of the inlet openings.

As already explained, the valves can optionally be continuous, modulated or pulsed open, the control allows for all these possibilities.

Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made.

• Figur 1 eine Längsschnittansicht durch einen erfindungsgemäßen Gasturbinenverdichter,
• Figur 2 eine Detailansicht des erfindungsgemäßen Verdichters im Bereich einer Laufschaufel, wobei Leitschaufeln zur Steigerung der Übersichtlichkeit weggelassen sind,
• Figur 3 eine perspektivische Draufsicht auf einen Teil des Verdichtergehäuses,
• Figur 4 eine vergrößerte Ansicht im Bereich eines Mikroventils, das beim erfindungsgemäßen Verdichter eingesetzt wird.

In the drawings show:

• FIG. 1 a longitudinal sectional view through a gas turbine compressor according to the invention,
• FIG. 2 a detailed view of the compressor according to the invention in the region of a blade, wherein guide vanes are omitted for clarity,
• FIG. 3 a perspective top view of a part of the compressor housing,
• FIG. 4 an enlarged view in the range of a microvalve, which is used in the compressor according to the invention.

In FIG. 1 is a multi-stage gas turbine compressor shown in axial design. The gas turbine compressor has an annular compressor housing 2, arranged on the housing 2 vanes 4 and a plurality arranged on a rotor 6 blades 8. Immediately upstream of the blade tip of a blade ring, the housing 2 on the circumference evenly distributed injection openings 10 on. Downstream of this blade ring 8, the housing 2 has outlet openings 12, are discharged via the compressed air from the annular channel 14 and, as shown by the arrow, is guided to the injection openings 10.

The air injected to stabilize the compressor flow is directed directly at the blade tip, such as FIG. 1 shows.

The amount of air blown in is controlled by valves 16 connected to a controller 18 (see FIG. FIG. 2 ) are controlled. The valves 16 are so-called microvalves, which in FIG. 4 are shown. These microvalves have dimensions of just about 10 x 15 mm surface and a thickness of about 1 mm and are particularly well to be placed on the outer housing 2 to save space.

Each injection port 10 has its own valve 16 associated therewith.

In FIG. 3 It can be seen that there is a kind of ring of valves 16 which extend around the housing 2 and are fixed directly to the housing 2.

In order to detect critical flow conditions directly, upstream and / or downstream of the injection openings 10 pressure sensors 20, 22 are mounted on the housing 2, which determine the pressure before, in the area or after the flown blades 8 (see FIG. 2 ).

There are distributed around the circumference numerous pressure sensors 20, 22 arranged as in FIG. 3 you can see.

The following is a more detailed on the microvalves, one of which in FIG. 4 can be seen in greatly enlarged representation.

With each valve 16, an actuator is coupled in each case. The actuator may be, for example, a small-sized magnetic coil 24 including plunger 26 or a piezo actuator. In FIG. 4 also the supply line 28 is shown for the branched air.

Overall, a large number (400 to 800) microvalves are attached to the housing 2, correspondingly many injection openings 10 are provided. Of course, several blade rings can be provided with its own ring of injection openings 10.

Depending on which pressure conditions are currently determined by the pressure sensors 20, 22, all valves 20, 22 are closed via the control 18 or individual or all valves 20, 22 are opened simultaneously or successively. Each valve 20, 22 is individually controlled so that synchronized control of all the valves 20, 22 is possible to produce any circumferential waveforms or circulating waves of injected air. These circumferential shafts can compensate for circumferential disturbances of the compressor flow, as the compressors can often exhibit modal flow disturbances in certain operating conditions that can be damped or completely extinguished by the targeted antiphase injection.

The targeted opening, closing or modulating the incoming air quantity for beam generation can be compared to a steady, steady inflow of branched air significantly reduced.

The controller 18 may also be integrated in the microvalves 16.

Of course, as soon as the critical operating region has been left, the valves 16 are closed again so as not to unnecessarily reduce the efficiency.

Claims (6)

1. Gas turbine compressor,
   having a compressor housing (2), guide blades (4), rotor blades (8) and valve-controlled blow-in openings (10) for stabilising the compressor flow, and having several valves (16) for controlling the amount of air blown in via the blow-in openings (10), wherein several sensors (20, 22) that are coupled to the control (18) of the valves (16) in the region of the rotor blades (8) are arranged in a distributed manner on the periphery of the flow passage (14), characterised in that the sensors are pressure sensors (20, 22) and are arranged upstream and downstream of the blow-in openings (10).
2. Gas turbine compressor according to claim 1, characterised in that the blow-in openings (10) are arranged directly upstream of the rotor blades (8) that additionally have air flowing through them.
3. Gas turbine compressor according to claim 1 or 2, characterised in that a specific valve (16) is allocated to each blow-in opening (10).
4. Gas turbine compressor according to one of the preceding claims, characterised in that the valves (16) are microvalves.
5. Method for stabilising the gas turbine compressor flow of a gas turbine compressor according to claim 1 by means of an electrical control (18) which is coupled to the valves (16) arranged on the periphery of the flow passage (14) at the blow-in openings (10),
   characterised in that,
   the pressure ratios in the flow passage (14) are determined and, depending on this, the valves (16) are controlled, and the pressure ratios are detected upstream and downstream of the blow-in openings (10).
6. Method according to claim 5, characterised in that the valves (16) are optionally opened continuously, with modulation or in a pulsing manner.

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