“Virtual engine” software usage for air bleed control in gte units' cooling systems

Аuthors

Gurevich O. S.^*, Gol'berg F. D.^**, Petukhov A. .^***, Zuev S. A.^****

Central Institute of Aviation Motors named after P.I. Baranov, CIAM, 2, Aviamotornaya str., Moscow, 111116, Russia

*e-mail: gurevich_os@ciam.ru
**e-mail: fdgolberg@ciam.ru
***e-mail: aapetukhov@ciam.ru
****e-mail: zuevsa@ciam.ru

Abstract

One of the trends of gas turbine engines perfecting consists in “intelligent” engine developing. Within its control system, a so-called “virtual engine” functions in real time mode, i. e. a full range thermo-gas-dynamic GTD model. Its implementation allows, in particular, realize engine control by its critical parameters inaccessible for measuring. The gas temperature in the hottest part of the engine duct, i. e. the temperature at the turbine inlet, is one of such parameters. The paper presents the result of the study of new turbine cooling control methods, differing fundamentally from conventional indirect open-loop control of air bleed valves according to rotation speed, employed in modern automatic control system. A block diagram and algorithmic provision of adaptive closed loop control of turbine cooling units operating directly according to gas temperature prior to the turbine and rate change of turbine blade temperature are considered.

The result of such type of control estimation, carried out as applied to modern turbofan engine with high bypass ratio, revealed that its' implementation may allow:

– Engine efficiency increasing by decreasing the bleeding air consumption;

– Engine lifetime increasing by turbine inlet temperature decreasing by 100...200 К at steady-state modes, and the rate of turbine blade temperature decreasing by more than 20% at transient modes.

An adaptive control of air bleeding for turbines cooling associated with gas temperature limitation by effecting on the fuel flow in the combustion chamber was considered. The paper demonstrates that its implementation is possible:

– In flying conditions, when maximum engine thrust is required. It can be increased by 10% with the maximum allowable limitation of turbine blade temperature;

– Under operation conditions when engine lifetime is critical. It allows blades temperature reduction by approximately 50 K while maintaining the thrust value and specific fuel consumption.

Keywords:

automatic control system, compressor air-bleed, turbine blades cooling, “virtual engine”

References

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