scholarly journals Dielectric Barrier Discharge (DBD) Plasma Actuators Thrust - Measurement Methodology Incorporating New Anti-Thrust Hypothesis

Author(s):  
David E. Ashpis ◽  
Matthew C. Laun
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).


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):  
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.


2013 ◽  
Vol 421 ◽  
pp. 163-167
Author(s):  
Feng Li ◽  
Chao Gao ◽  
Bo Rui Zheng ◽  
Yu Shuai Wang

The boundary layer aerodynamic flow acceleration with one atmosphere uniform induced by multiple dielectric-barrier-discharge plasma actuation were studied based on PIV. Through double actuators alternating discharge, the multiple dielectric barrier discharge mode have been proposed and tested. The efficiencies of the plasma actuators in Pulsed-pulsed, Steady-steady, Pulsed-steady and Steady-pulsed discharge modes were explored. Based on the above results, the boundary layer flow acceleration performance of multiple plasma actuators has been discussed and the more efficient discharge pattern has been proposed. The results of this study indicate that the airflow acceleration effect of multiple plasma actuators mainly occurs in paraelectric direction and the pulsed-pulsed is the more efficient multiple plasma actuation mode.


Author(s):  
José C. Páscoa ◽  
Frederico F. Rodrigues ◽  
Shyam S. Das ◽  
M. Abdollahzadeh ◽  
A. Dumas ◽  
...  

The paper presents a study on a Coanda nozzle with applications in vectorized propulsion. The nozzle is able to change the exist flow angle as a function of a differential two-stream incoming flow rate. Herein we demonstrate that by using Dielectric Barrier Discharge actuators we are able to extend the range of attainable exit flow angles. First the analysis is performed using a numerical approach; afterwards an experimental facility is implemented to study this same effect. We include a comparison between the experimental testing on the Coanda thruster and CFD computations. Following an analysis of the results we demonstrate that it is possible to achieve a higher exit thrust angle, with the DBD plasma actuators active, and this is shown to be important in order to be able to keep the desired angles under several swirl velocities incoming from the feeding turbofans.


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


Author(s):  
GH Maleki ◽  
Ali R Davari ◽  
MR Soltani

Effects of dielectric barrier discharge plasma have been studied on the wake velocity profiles of a section of a 660 kW wind turbine blade in plunging motion in a wind tunnel. The corresponding unsteady velocity profiles show remarkable improvement when the plasma actuators were operating and the angles of attack of the model were beyond the static stall angles of the airfoil. As a result the drag force was considerably reduced. It is further observed that the plasma-induced flow attenuates the leading edge vortices that are periodically shed into wake and diminishes the large eddies downstream. The favorable effects of the plasma augmentation are shown to occur near the uppermost and lowermost positions of the plunging paths where the wake is primarily dominated by the vortices of the same sign. The wake structure in the presence of the flow induced by the plasma actuators shows that the actual effective angles of attack seen by the plunging airfoil reduces in comparison with that for the case of the plasma augmentation off situation.


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