Compensating the Effects of Hazardous External Influences on the Engine Performance by Control Methods 2019-01-1862
Aircraft equipment is operated in a wide range of external conditions, which, with a certain combination of environmental parameters, can lead to icing of the internal structural elements of the engine. Due to icing the engine components performance change what leads to decrease in thrust, gas dynamic stability, durability, etc. Similar effect has a volcanic ash sucked into the engine flow-path. The safe aircraft operation and its desired performance may be lost as a result of such external influences.
The impact of this factors on the engine performance depends on the engine control methods. Therefore, it is relevant to study control methods that allow fully or partly compensate the effect of engine components performance degradation.
The focus of this paper is to determine the control methods of an aircraft gas turbine engine aimed at solving this problem. The object of the study is a modern commercial engine with a bypass ratio of about 9.
In this paper analysis of the effect of icing and volcanic ash sucking on the engine components performance is conducted. It is shown that in case of such external influences a flow capacity, efficiency and surge margin of the low-pressure compressor change. The obtained data were provided to the physics-based dynamic turbofan model. Control algorithms for this model were developed applied to various regulated variables used in the setpoint controllers of modern engines (the fan speed, the engine pressure ratio, etc.) to simulate engine performance with each kind of a controller. Additionally, the engine control method using the thrust value provided by the on-board engine model is considered. Simulation results of the engine performance for steady-state and transient operating modes with different types of controllers are given. The optimal engine control method which allow compensating the negative effect of the engine components performance degradation is determined.
Oskar Gurevich, Sergei Smetanin, Mikhail Trifonov