Home > Events > PhD Candidate Ryan C. McGowan - "The Pulsed-DC Plasma Actuator: Characteristics and Stall Control In Axial Compressors and Fans"

PhD Candidate Ryan C. McGowan - "The Pulsed-DC Plasma Actuator: Characteristics and Stall Control In Axial Compressors and Fans"

Start: 11/16/2017 at 1:00PM
End: 11/16/2017 at 4:30PM
Location: 103 Multidisciplinary Research Building
Event Type:
  • Ph.D. Defense
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A new means of powering dielectric barrier discharge (DBD) plasma actuators that utilizes a pulsed-DC waveform is proposed for preventing or delaying stall inception in axial compressors and fans. The plasma actuator arrangement, like most AC DBD designs, has two staggered electrodes that are separated by an insulating dielectric layer. However, instead of an AC voltage input to drive the actuator, the pulsed-DC DBD utilizes a DC voltage source. The DC source is supplied to both electrodes and remains constant in time for the exposed electrode, while a resistor limits the current to the covered electrode. A fast-acting solid-state switch periodically grounds the covered electrode for very short instants and then allows its voltage to rise to the source DC level. This process results in a larger peak induced velocity than that from a purely AC waveform such as a sine or sawtooth wave. Experiments to examine the relevant characteristics for optimizing the pulsed-DC plasma actuator, including frequency, voltage, dielectric material, and static pressure, are presented. A predictive model of stall margin extension (SME) in the Notre Dame Transonic Axial Compressor (ND-TAC) facility is also developed; a plasma-actuator-generated thrust of 300 mN/m is found to result in a 3.4% SME at design conditions. To validate the actuators’ ability to interact with and modify the formation of stall cells, a facility has been designed and constructed around a nonconductive fan rotor. The actuators are installed in the fan casing near the blade tips. The instrumentation allows for the measurement of rotating pressure disturbances (traveling stall cells) in this tip gap region as well as fan performance characteristics including pressure rise and flow rate. The casing plasma actuation successfully reduces the correlation of the rotating stall cells, thereby extending the stall margin of the fan. Various azimuthal arrangements and input voltage levels for the plasma actuator casing treatment are explored to determine optimum conditions.

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