Evaluation of the Operational State of a Small Turbojet Engine Using Variations in Its Near Magnetic Field.

Different parameters, which are obtained using classical sensors, are nowadays used to determine the technical state of turbojet engines. In order to expand and to improve this evaluation a novel idea in this area is presented that variations in the near magnetic field of an operational turbojet engine can contain valuable information about its state. Data analysis in different operational states of a small running turbojet engine is presented describing dynamical changes in magnetic induction in the near magnetic field in laboratory conditions. In order to detect the operational state of the engine using magnetic induction derivatives an infinite impulse response filter of the fourth order was designed with cut-off frequency of 2 Hz and expanded by a derivative element. The expanded filter was used to create a linear predictive model, which can be used to compute the rotational speed and exhaust gas temperature of a small turbojet engine using derivatives in magnetic induction in its near magnetic field. [ABSTRACT FROM AUTHOR]