Aircraft single-spool single-jet engine with variable area exhaust nozzle

This paper deals with an aircraft single-spool single-jet engine equipped with variable area exhaust nozzle. Nozzle´s exhaust area controller was studied in some previous papers; one has chosen the controller based on turbine´s pressure ratio, completed with flight regime corrector. The studied aircraft engine is VK-1F type; its mathematical model, its transfer functions for main and secondary parameters, as well as their co-efficient for a constant operating regime were here deduced. The embedded system (engine + exhaust nozzle) was identified as a single input system (which is the throttle´s angular displacement θ) with an inner feedback after the engine´s speed n; main system outputs are the speed n and the combustor temperature T₃*. One has built the block diagram with transfer functions, which was the basic system for further Matlab simulations. System´s quality has been studied in two cases: considering only the engine with exhaust nozzle (JEVEN), having as single input the fuel flow rate Q_c, respectively considering the embedded system, where the fuel flow rate is controlled by an appropriate controller (FIC). Simulation results were compared with other similar cases in the literature. Paper´s content, conclusions and observations can be used for further studies, such as studies concerning aircraft double- or multiple-spool jet engines with variable area exhaust nozzles, without or with afterburning.