In some instances, ice can form on the surface of a compressor airfoil. If
the ice dislodges, it can impact and damage other compressor components.
Aspects of the invention relate to systems for detecting the presence of
ice or water on a compressor vane during engine operation. A ceramic
insulating coating can be deposited on a portion of the surface of the
vane. A heater and a thermocouple can be provided near the outermost
surface of the coating such that the thermocouple can sense heat from the
heater. The heater and the thermocouple can be provided within the
coating. The presence of water film and/or ice on the coating surface can
be detected by taking a thermocouple measurement following a heater
pulse. The presence of a water film or ice results in a delay in the
temperature rise detected by the thermocouple.