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Wicks M.,University of Notre Dame | Wicks M.,Institute for Flow Physics and Control | Thomas F.O.,University of Notre Dame | Thomas F.O.,Institute for Flow Physics and Control
AIAA Journal | Year: 2015

A study was conducted to investigate the effect of relative humidity (RH) on the reactive thrust produced by a dielectric barrier discharge (DBD) plasma actuator. It is observed that the performance metric of reactive thrust is directly proportional to the actuator-induced body force and was measured directly by a procedure similar to that used in the plasma actuator optimization study conducted by Thomas and other researchers. A Hamilton Beach True Air Ultrasonic Humidifier was installed inside the closed chamber to control the RH level. The chamber was instrumented with two Honeywell type HIH-4031 RH sensors located on either side of the plasma actuator. These were used for real-time monitoring of the RH inside the chamber. Source


Valerioti J.A.,University of Notre Dame | Valerioti J.A.,Institute for Flow Physics and Control | Corke T.C.,University of Notre Dame | Corke T.C.,Institute for Flow Physics and Control
AIAA Journal | Year: 2012

Single dielectric barrier discharge plasma actuators were investigated for a range of static pressures from 0.17 to 9.0 bar. The actuator minimum ionization voltage and static thrust were measured and similar data in the literature. The minimum ionization voltage decreased with decreasing pressure; however, at a given pressure, the ionization voltage scaled with the actuator capacitance per unit area. The static thrust was found to have a minimum at a pressure of approximately 2 bar. A narrow local maximum was found near 0.9 bar, below which the thrust decreased. A second broad local maximum occurred near 6 bar. The location of the two local maxima, respectively, moved to lower and higher pressures as the actuator voltage increased. At any pressure, thrust scaled with voltage to a power. The power-law exponent increased linearly with increasing pressure from the lowest pressure tested to approximately 5 bar. Above 5 bar, the power-law exponent asymptotes to approximately 7.3, which was approximately twice that at atmospheric pressure. The experimental results were evaluated using a space-time lumped-element model for single dielectric barrier discharge plasma actuators. The overall trends were found to be best modeled through a pressure dependence of the minimum ionization voltage and the electron density. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. Source


Stephens J.E.,University of Notre Dame | Stephens J.E.,Institute for Flow Physics and Control | Corke T.,University of Notre Dame | Corke T.,Institute for Flow Physics and Control | And 2 more authors.
Journal of Propulsion and Power | Year: 2011

An experiment was conducted in a linear cascade of Pratt and Whitney Pack-B turbine blades to simulate the flow in the tip-gap region of a low-pressure turbine blade row. The objective was to investigate the sensitivity of the tipclearance flow to blade-mounted plasma actuators designed to improve the net pressure loss coefficient. Investigations were performed at inlet Reynolds numbers of 0.2 × 106 and 0.5 × 106, corresponding to inlet Mach numbers of 0.08 and 0.2 and exit Mach numbers of 0.13 and 0.3, respectively. The gap-to-chord ratio was 4%. The flow was documented using endwall static pressure measurements and downstream pressure measurements using a five-hole pitot probe. The plasma actuators were operated to excite periodic disturbances that could couple with instabilities associated with the separated shear layer or bulk flow jetting from under the blade-wall gap. At the lower Reynolds number, the unsteady excitation resulted in as much as a 15% increase in mass-averaged total pressure loss. However, at the higher Reynolds number, the opposite occurred with a maximum of a 12.6% decrease in the total pressure loss. Both occurred at an actuator disturbance frequency that suggested that the actuator excited an instability of the shear layer between the tip-clearance flow and the passage flow. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc. Source

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