High Bandwidth Plasma Sensor Suite for Flow Parameter and Vibration Measurement

Spectral Energies, LLC in collaboration with University of Notre Dame is developing a “suite" of ac-driven, weakly-ionized plasma devices configured as flush-mounted high-bandwidth sensors to measure quantities that are important to gas-turbine engine performance. The sensors are designed for surface pressure, shear stress, gas temperature and gas species. The design of these devices is based on the “plasma anemometer" developed by Matlis et al. for measurement of mean and dynamic mass-flux in hypersonic flows. The sensors use metallic electrodes driven by ac-voltage waveforms to locally ionize the gas. The properties of the ionized gas uniquely correlate with the local conditions and can be sensed through changes in the applied ac waveform. The design of the electrodes and choice of discharge regime varies depending on gas property to be sensed. We will continue to refine and test the design while documenting static and dynamic sensitivity. A test is planned with General Electric Aviation to place a plasma sensor on a full-scale gas-turbine as part of the LEAP56 core engine program. The objective is to develop a compressor stall prediction capability. The sensor “suite" represents a new generation of sensing devices that can operate in high enthalpy and vibration-loaded conditions.