RU2820083C1 - Method of providing gas-dynamic stability of axial compressor - Google Patents

Abstract

FIELD: gas turbine engine building.

SUBSTANCE: invention relates to methods of providing gas-dynamic stability of axial compressors under operating conditions and changing parameters at which their stable operation was initially disturbed. Technical task of the proposed invention is to ensure the stable operation of axial compressors under operating conditions and changing parameters, at which their stable operation was initially disturbed. Technical result is achieved by the fact that in the disclosed method of providing gas-dynamic stability of axial compressors during their operation and changing parameters, the critical stages of the axial compressor are determined, working medium injection points in critical stages of axial compressor are selected, parameters of injected working medium are calculated, parameters of injected working medium are set, moment of working medium blowing is determined; working medium is blown with preset parameters in selected places.

EFFECT: stable operation of axial compressors under operating conditions and variation of parameters at which their stable operation was initially disturbed.

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Description

The invention relates to the field of gas turbine engine building, in particular to methods for ensuring the gas-dynamic stability of axial compressors under operating conditions and changing the parameters under which their stable operation was initially disrupted.

An axial compressor is one of the main elements of a gas turbine engine. A compressor is a bladed machine in which energy is imparted to the air to increase its total pressure.

Stability is the ability of a system to maintain its current state in the presence of external influences.

Dynamic stability is the property of a system to maintain the original or close to the original mode under finite disturbances.

Gas-dynamic stability of a gas turbine engine - the ability of a gas turbine engine to operate without violating gas-dynamic stability in the presence of external influences

Violation of the stable operation of a gas turbine engine, called loss of gas-dynamic stability (GDS) of the engine, is one of the most dangerous failures of an aircraft gas turbine engine.

The gas-dynamic stability of a gas turbine engine is mainly determined by the gas-dynamic stability of axial compressors.

Gas-dynamic stability of an axial compressor is the ability of an axial compressor to operate without rotating stall and surge in the presence of external influences.

Rotating stall is characterized by moving stall zones, covering sequentially against the direction of rotation of the impeller, groups of its blades, but in the direction of rotation of the impeller relative to the compressor housing.

Surge is a loss of dynamic stability, characterized by a non-stationary low-frequency process in which compressed air (gas) periodically breaks through from the outlet to the inlet of the compressor.

There are known methods for ensuring gas-dynamic stability of axial compressors of gas turbine engines, such as reducing the fuel supply to the main and afterburner combustion chambers, rotating the guide vanes, opening the nozzle, and reducing the throat area of adjustable supersonic air intakes. The disadvantage of such methods is the loss of thrust (power) of gas turbine engines due to their use. There is a known method for short-term increasing the gas-dynamic stability margin of gas turbine engines [Patent No. 2261351 C1 Russian Federation, IPC 02C 9/00. Method for short-term increase in gas-dynamic stability reserves of a gas turbine engine: No. 2004108105/06: application. 03/22/2004: publ. 09.27.2005 / Gelmedov F.Sh., Muntyanov I.G., Muntyanov G.L., Sereda S.O.; applicant FSUE "CIAM named after. P.I. Baranova. - 9 p.: ill. - Text: direct] by injecting coolant through injectors against the flow into the compressor inlet. The disadvantages of this method are the energy consumption for injecting liquid against the flow and time limitation of application, which reduces the efficiency of the method.

In the work [Kolesinsky, L.D. Analysis of the occurrence of unsteady phenomena in a multi-stage compressor operating in a stand system during surge / L.D. Kolesinsky. - Text (visual): direct // Scientific notes of TsAGI. - 2008. - No. 4. Volume XXXIX. - P. 46-59] the processes of development of rotating stall and violation of the gas-dynamic stability of axial compressors were studied. The concepts of primary vortex zones, critical and control stages are introduced. The phenomena preceding the occurrence of a compressor stall, as well as the sequence of events after the occurrence of a stall, leading to a rotating stall, have been studied. The main stages of development of rotating stall have been established:

the formation of primary vortex zones on part of the blade height - the occurrence of separation in the flow part of the compressor when the latter operates near the stall boundary;

the occurrence of a compressor stall - the end of the formation of primary vortex zones;

initial instability in the first (critical) stages of the compressor (development of a stall zone along the radius and circumference);

the transition of the last of the critical (control) steps to the left branch of its characteristics;

final formation along the radius and circumference of the stall zone in the first critical stages;

alternate initiation of disruption in subsequent critical stages;

the occurrence of flow instability in the compressor as a whole. Compressor stage - part of the compressor, including the impeller and the guide vane located behind it.

Critical stages are the stages in which primary vortex zones are generated and transformed into a rotating stall; as a rule, these are the first stages of compressors.

Control stages are the last of the critical stages, the first to move to the left branch of their characteristics during the development of a rotating stall

The technical objective of the claimed invention is to ensure stable operation of axial compressors under operating conditions and changes in parameters under which their stable operation was initially disrupted.

The technical result is stable operation of axial compressors under operating conditions and changes in parameters under which their stable operation was initially disrupted.

The technical result is achieved by the fact that in the inventive method for ensuring the gas-dynamic stability of axial compressors during their operation and changing parameters, the critical stages of the axial compressor are determined, the places of injection of the working fluid in the critical stages of the axial compressor are selected, the parameters of the injected working fluid are calculated, the parameters of the injected working fluid are set, and the parameters of the injected working fluid are determined. moment of injection of the working fluid, the working fluid is injected with the specified parameters in selected locations.

The working fluid is understood as air or other gas, or a liquid that is converted into steam.

The working fluid can be blown from the housing above the impeller [Patent No. 2582537 Russian Federation, IPC F04D 29/68 (2006.01). Axial compressor: No. 2014117379/06: appl. 04/29/2014: publ. 11/10/2015 / Klepikov D.S., Alekseev I.I., Cherkasov A.N., Alekseev A.A., Sharafutdinov A.G., Zvonnikov V.I.; applicant VUNTS Air Force "VVA". - 11 p.: ill. - Text: direct.], housings above the guide vanes, impeller bushings [Patent No. 2633221 Russian Federation, IPC F04D 29/00 (2006.01). Axial compressor: No. 2016122577: app. 06/07/2016: publ. 10.11.2017 / Cherkasov A.N., Alekseev I.I., Klepikov D.S., Popov A.E.; applicant VUNTS Air Force "VVA". - 5 p.: ill. - Text: direct.], guide vane bushings [Patent No. 2694454 Russian Federation, IPC F04D27/02 (2006.01). Axial compressor: No. 2018140104: app. 11/13/2018: publ. 07/15/2019 / Cherkasov A.N., Alekseev I.I., Kirillov A.A.; applicant VUNTS Air Force "VVA". - 6 p.: ill. - Text: direct.].

Injection points are holes at the outlet of channels with given geometric parameters through which the working fluid is injected. The geometric parameters of the channels are determined from the conditions of the required direction of the injected air, manufacturability, minimum hydraulic resistance, and ensuring the necessary parameters of the injected working fluid. The injection points can be located in the housing above the impeller, in the housing above the steering device, on the impeller bushing, or on the guide vane bushing.

The injection locations are determined from the condition of the effective impact of injection on the secondary flows in the axial compressor stage.

The calculation of the parameters of the injected working fluid is aimed at finding their optimal values, ensuring maximum efficiency from the injection of the working fluid. The main parameters of the injected working fluid are usually understood as the speed, direction of injection and flow rate of the working fluid.

The injection speed and the flow rate of the working fluid are set by adjusting the parameters in the system for supplying the working fluid to the injection points. The injection direction is determined by the geometric parameters of the injection channels, which are calculated and specified at the compressor design stage.

Claims (1)

A method for ensuring the gas-dynamic stability of an axial compressor, which consists in injecting a working fluid into at least one of the stages of the axial compressor, characterized in that the critical stages of the axial compressor are determined, the injection locations of the working fluid in the critical stages of the axial compressor are selected, the parameters of the injected working fluid are calculated, and parameters of the injected working fluid, determine the moment of injection of the working fluid, and inject the working fluid with the specified parameters in selected places.