Detection of the Impact of Ice Crystal Accretion in an Aircraft Engine Compression System During Dynamic Operation

The accretion of ice in the compression system of commercial gas turbine engines operating in high ice water content conditions is a safety issue being studied by the aviation community. While most of the research focuses on the underlying physics of ice accretion and the meteorological conditions in which accretion can occur, a systems-level perspective on the topic lends itself to potential near-term operational improvements. Here a detection algorithm is developed which has the capability to detect the impact of ice accretion in the Low Pressure Compressor of an aircraft engine during steady flight as well as during changes in altitude. Unfortunately, the algorithm as implemented was not able to distinguish throttle changes from ice accretion and thus more work remains to be done. Nomenclature C-MAPSS40k the Commercial Modular Aero-Propulsion System Simulation 40,000 lbf EPR Engine Pressure Ratio (P50/P2) H fault influence coefficient matrix HIWC High Ice Water Content K input influence coefficient matrix LPC Low Pressure Compressor LPC% LPC efficiency (%) LPCeff LPC efficiency health parameter LPCflow LPC flow capacity health parameter LPCw LPC mass flow rate (lbm/s) LPCnom nominal LPC characteristic m vector of input shifts Nc Core shaft speed (rpm) Nf Fan shaft speed (rpm) Px Pressure at station x (psia) PLA Power Lever Angle (deg) R sensor noise covariance matrix Tx Temperature at station x (degree Rankine) w vector of sensor measurement noise x vector of health parameter shifts estimated vector of health parameter shifts