Highly responsive multi-flow pattern generation by multi-electrode plasma actuator using a single power supply

2021 ◽  
Author(s):  
Kosuke Sugimoto ◽  
Satoshi Ogata
Keyword(s):  
Flow Control ◽  
Flow Pattern ◽  
Power Supply ◽  
Active Flow Control ◽  
Flow Patterns ◽  
Plasma Actuator ◽  
Pattern Generation ◽  
Switching Frequency ◽  
Wall Jet ◽  
Active Flow

Abstract A dielectric-barrier-discharge plasma actuator (DBD-PA) is an active flow-control device that uses ionic wind generated by electrohydrodynamic (EHD) forces. A DBD-PA controls fluid motion and offers quick response without the need for moving parts. Previous studies have proposed methods for generating various flow patterns with a DBD-PA for fluid control. This paper presents a method for generating multiple flow patterns using a multi-electrode DBD-PA that is driven by a single-channel high-voltage power supply with a relay circuit. In contrast, conventional methods of realizing multiple flow patterns involve the use of a multi-channel power supply. Hence, they have the disadvantage of requiring a complicated power supply system. The proposed method succeeded in realizing several induced-flow modes involving the generation of a directionally controllable wall jet, various sizes of vortices, and an upward jet by altering the switching frequency and switching ratio. In addition, our experimental results indicate that the proposed method can control the flow pattern with a significantly short response time. The direction of the wall jet can be switched within tens to hundreds of milliseconds. Therefore, the proposed method combines simplicity and versatility and is expected to facilitate the realization of multifunctional active flow control in various flow fields, such as flow turbulent boundary layer control, thermal diffusion control, gas mixing, and flame-stability enhancement.

Experimental and Numerical Analysis of a Micro Plasma Actuator for Active Flow Control in Turbomachinery

2014 ◽  
Author(s):  
Maria Grazia De Giorgi ◽  
Elisa Pescini ◽  
Fedele Marra ◽  
Antonio Ficarella
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Plasma Actuator ◽  
The Body ◽  
Plasma Actuators ◽  
Compressor Cascade ◽  
Barrier Discharge Plasma ◽  
Induced Flow ◽  
The One ◽  
Active Flow

Nowadays several active flow control systems, particularly dielectric barrier discharge plasma actuators, appear to be effective for the control of flow stream separation and to improve performance of turbomachinery. However these applications require high actuation strength, higher than the one generated by conventional macro plasma actuators. Research is actually improving the design of plasma actuator in order to enhance the flow control capability and reduce the power consumption. In this contest, this work concerns the implementation of a micro plasma actuator for the active control in a compressor cascade. For this aim, firstly the micro actuator was developed and an experimental characterization of the flow induced by the device was done. The induced flow field was studied by means of Particle Image Velocimetry and Laser Doppler Velocimetry. The dissipated power was also evaluated. Experimental results were used to validate a multi-physics numerical model for the prediction of the body forces induced by the plasma actuator. Finally, the obtained body force field was used for modeling the separation control by means of the micro plasma actuator in a highly-loaded subsonic compressor stator.

scholarly journals Effects of Input Voltage and Freestream Velocity on Active Flow Control of Passage Vortex in a Linear Turbine Cascade Using Dielectric Barrier Discharge Plasma Actuator

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 764 ◽  
Author(s):  
Takayuki Matsunuma ◽  
Takehiko Segawa
Keyword(s):  
Flow Control ◽  
Dielectric Barrier Discharge ◽  
Barrier Discharge ◽  
Active Flow Control ◽  
Plasma Actuator ◽  
Turbine Cascade ◽  
Freestream Velocity ◽  
Dielectric Barrier ◽  
Passage Vortex ◽  
Active Flow

Passage vortex exists as one of the typical secondary flows in turbomachines and generates a significant total pressure loss and degrades the aerodynamic performance. Herein, a dielectric barrier discharge (DBD) plasma actuator was utilized for an active flow control of the passage vortex in a linear turbine cascade. The plasma actuator was installed on the endwall, 10 mm upstream from the leading edge of the turbine cascade. The freestream velocity at the outlet of the linear turbine cascade was set to range from UFS,out = 2.4 m/s to 25.2 m/s, which corresponded to the Reynolds number ranging from Reout = 1.0 × 104 to 9.9 × 104. The two-dimensional velocity field at the outlet of the linear turbine cascade was experimentally analyzed by particle image velocimetry (PIV). At lower freestream velocity conditions, the passage vortex was almost negligible as a result of the plasma actuator operation (UPA,max/UFS,out = 1.17). Although the effect of the jet induced by the plasma actuator weakened as the freestream velocity increased, the magnitude of the peak vorticity was reduced under all freestream velocity conditions. Even at the highest freestream velocity condition of UFS,out = 25.2 m/s, the peak value of the vorticity was reduced approximately 17% by the plasma actuator operation at VAC = 15 kVp-p (UPA,max/UFS,out = 0.18).

Robust Active Flow Control of a Stator Cascade With Integer Control Functions and Sum-Up Rounding

2019 ◽  
Author(s):  
Karl Neuhäuser ◽  
Rudibert King
Keyword(s):  
Robust Control ◽  
Flow Control ◽  
Active Flow Control ◽  
Control Variable ◽  
Principal Component ◽  
Control Algorithms ◽  
Switching Frequency ◽  
Binary Control ◽  
Active Flow ◽  
Control Output

Abstract This work is part of a research initiative that aims at increasing the overall gas turbine efficiency by means of constant volume combustion (CVC). For that purpose, flow control in the compressor becomes important, since unsteady combustion effects that may occur in a CVC are very likely to affect stability and efficiency of the compressor negatively due to flow disturbances. Active Flow Control (AFC) often has to deal with uncertain flow conditions, e.g., due to turbulence, varying operating ranges, or simply environmental effects. By that, system parameters such as gain or time constants of the system model also become uncertain, making it difficult for control algorithms to ensure optimality or even stable behavior. Robust control in the sense of ℋ∞ control tackles these problems using an uncertainty description and a nominal model of the system. In this contribution, robust control applied to a linear stator cascade is addressed when only a binary control output from solenoid valves is available. Moreover, a surrogate control variable is proposed, describing the extent of the velocity deficit. By means of a principal component analysis, this control variable is reconstructed from a single measurement input. AFC is realized via trailing edge blowing. In comparison to proportional valves, solenoid valves are cheaper and offer faster switching times with the drawback of a restricted range of the control output to integer or even binary values. Since the ℋ∞ controller, as well as most other control algorithms, results in a real-valued signal u(t) ∈ ℝ, a sum-up rounding strategy is applied to the controller output, forming a binary control output ub (t) ∈ {0, 1}. Although it is impossible for the two outputs to completely match, unless both are integer-valued, there is proof that the difference of real-valued to binary output is bounded in its integral value. The investigations show that a switching frequency of the valves of 100 Hz is sufficient to ensure that the control error via binary control matches its expected equivalent via real-valued control for the presented system.

scholarly journals Active flow control on a NACA 23012 airfoil model by means of magnetohydrodynamic plasma actuator

2016 ◽  
Vol 774 ◽  
pp. 012153 ◽  
Author(s):  
P N Kazanskiy ◽  
I A Moralev ◽  
V A Bityurin ◽  
A V Efimov
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Plasma Actuator ◽  
Active Flow
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