Dielectric Barrier Discharge (DBD) Plasma Actuators for Flow Control in Turbine Engines: Simulation of Flight Conditions in the Laboratory by Density Matching

2019 ◽  
Vol 36 (2) ◽  
pp. 157-173
Author(s):  
David E. Ashpis ◽  
Douglas R. Thurman

Abstract We address requirements for laboratory testing of AC Dielectric Barrier Discharge (AC-DBD) plasma actuators for active flow control in aviation gas turbine engines. The actuator performance depends on the gas discharge properties, which, in turn, depend on the pressure and temperature. It is technically challenging to simultaneously set test-chamber pressure and temperature to the flight conditions. We propose that the AC-DBD actuator performance depends mainly on the gas density, when considering ambient conditions effects. This enables greatly simplified testing at room temperature with only chamber pressure needing to be set to match the density at flight conditions. For turbine engines, we first constructed generic models of four engine thrust-classes; 300-, 150-, 50-passenger, and military fighter, and then calculated the densities along the engine at sea-level takeoff and altitude cruise conditions. The range of chamber pressures that covers all potential applications was found to be from 3 to 1256 kPa (0.03 to 12.4 atm), depending on engine-class, flight altitude, and actuator placement in the engine. The engine models are non-proprietary and can be used as reference data for evaluation requirements of other actuator types and for other purposes. We also provided examples for air vehicles applications up to 19,812 m (65,000 ft).

Author(s):  
David E. Ashpis ◽  
Douglas R. Thurman

Dielectric Barrier Discharge (DBD) plasma actuators for active flow control in the jet engine need to be tested in the laboratory to characterize their performance at flight operating conditions. DBD plasma actuators generate a wall-jet electronically by creating weakly ionized plasma, therefore their performance is affected by gas discharge properties, which in turn depend on the pressure and temperature at the actuator placement location. Characterization of actuators is initially performed in a laboratory chamber without external flow. It is usually impractical to simultaneously set engine pressures and temperatures in a chamber, and a simplified approach is desired. It is assumed that the plasma discharge depends only on the gas density. Other temperature effects are assumed to be negligible. Therefore, tests can be performed at room temperature with chamber pressure set to yield the same density as in engine operating flight conditions. Engine data was obtained from four generic engine models; 300-, 150-, and 50-Passenger (PAX) aircraft engines, and a military jet-fighter engine. The static and total pressure, temperature, and density distributions along the engine were calculated for sea-level takeoff and altitude cruise, and the chamber pressures needed to test the actuators were calculated. The results show that testing has to be performed over a wide range of pressures from 12.4 to 0.03 atm, depending on the application. For example, if a DBD plasma actuator is to be placed at the compressor exit of a 300 PAX engine, it has to be tested at 12.4 atm for takeoff, and 6 atm for cruise conditions. If it is to be placed at the low-pressure turbine, it has to be tested at 0.5 and 0.2 atm, respectively. These results have implications for the feasibility and design of DBD plasma actuators for jet engine flow control applications. In addition, the distributions of unit Reynolds number, Mach number, and velocity along the engine are provided. The engine models are non-proprietary and this information can be used for evaluation of other types of actuators and for other purposes.


2020 ◽  
Author(s):  
Miguel André Barbosa Moreira ◽  
Frederico Miguel Freire Rodrigues ◽  
José Carlos Páscoa Marques

The objective of this study is to compare the effect of varying the material used as dielectric layer on the properties of the plasma actuators themselves. The experiments have shown that actuators with a PIB dielectric have a lower power consumption, can achieve higher velocities and have a better mechanical efficiency, but are more prone to failure due to breakdown of the dielectric. We verified that PIB rubber is a suitable material for DBD plasma actuators fabrication presenting several interesting features. Keywords: Active flow control, Plasma actuators, Dielectric barrier discharge, Dielectric materials


2018 ◽  
Vol 140 (10) ◽  
Author(s):  
F. F. Rodrigues ◽  
J. C. Pascoa ◽  
M. Trancossi

Dielectric barrier discharge (DBD) plasma actuators have several applications within the field of active flow control. Separation control, wake control, aircraft noise reduction, modification of velocity fluctuations, or boundary layer control are just some examples of their applications. They present several attractive features such as their simple construction, very low mass, fast response, low power consumption, and robustness. Besides their aerodynamic applications, these devices have also possible applications within the field of heat transfer, for example film cooling applications or ice formation prevention. However, due to the extremely high electric fields in the plasma region and consequent impossibility of applying classic intrusive techniques, there is a relative lack of information about DBDs thermal characteristics. In an attempt to overcome this scenario, this work describes the thermal behavior of DBD plasma actuators under different flow conditions. Infra-red thermography measurements were performed in order to obtain the temperature distribution of the dielectric layer and also of the exposed electrode. During this work, we analyzed DBD plasma actuators with different dielectric thicknesses and also with different dielectric materials, whose thermal behavior is reported for the first time. The results allowed to conclude that the temperature distribution is not influenced by the dielectric thickness, but it changes when the actuator operates under an external flow. We also verified that, although in quiescent conditions the exposed electrode temperature is higher than the plasma region temperature, the main heat energy dissipation occurs in the dielectric, more specifically in the plasma formation region.


Author(s):  
João Nunes‐Pereira ◽  
Frederico Freire Rodrigues ◽  
Mohammadmahdi Abdollahzadehsangroudi ◽  
José Carlos Páscoa ◽  
Senentxu Lanceros‐Mendez

2017 ◽  
Vol 31 (32) ◽  
pp. 1850038 ◽  
Author(s):  
Xin Zhang ◽  
Huaxing Li ◽  
Kwing So Choi ◽  
Longfei Song

The structures of a flow field induced by a plasma actuator were investigated experimentally in quiescent air using high-speed Particle Image Velocimetry (PIV) technology. The motivation behind was to figure out the flow control mechanism of the plasma technique. A symmetrical Dielectric Barrier Discharge (DBD) plasma actuator was mounted on the suction side of the SC (2)-0714 supercritical airfoil. The results demonstrated that the plasma jet had some coherent structures in the separated shear layer and these structures were linked to a dominant frequency of [Formula: see text] = 39 Hz when the peak-to-peak voltage of plasma actuator was 9.8 kV. The high speed PIV measurement of the induced airflow suggested that the plasma actuator could excite the flow instabilities which lead to production of the roll-up vortex. Analysis of transient results indicated that the roll-up vortices had the process of formation, movement, merging and breakdown. This could promote the entrainment effect of plasma actuator between the outside airflow and boundary layer flow, which is very important for flow control applications.


2011 ◽  
Vol 69 (4) ◽  
pp. 302-312 ◽  
Author(s):  
Jochen Kriegseis ◽  
Benjamin Möller ◽  
Sven Grundmann ◽  
Cameron Tropea

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