Download or read book Numerical Modeling of Microscale Plasma Actuators written by Chin-Cheng Wang and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary weakness of DBD actuators is the relatively small actuation effect as characterized by the induced flow velocity. To improve upon this weakness for high speed flow control, the microscale discharge may be a remedy for increasing electric force.

Download or read book Dielectric Barrier Discharge Microplasma Actuator for Flow Control written by Kazuo Shimizu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventional actuators due to their simple construction, lack of moving parts, and fast response. This type of actuator modifies the airflow due to electrohydrodynamic (EHD) force. The EHD phenomenon occurs due to the momentum transfer from charged species accelerated by an electric field to neutral molecules by collision. This chapter presents a study carried out to investigate experimentally and by numerical simulations a micro-scale plasma actuator. A microplasma requires a low discharge voltage to generate about 1 kV at atmospheric pressure. A multi-electrode microplasma actuator was used which allowed the electrodes to be energized at different potentials or waveforms, thus changing the direction of the flow. The modification of the flow at various time intervals was tracked by a high-speed camera. The numerical simulation was carried out using the Suzen-Huang model and the Navier-Stokes equations.

Download or read book Actuators written by Constantin Volosencu and published by BoD – Books on Demand. This book was released on 2018-07-11 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book promotes new research results in the field of modern actuators and their applications. New coverage of dielectric barrier discharge plasma actuators, polymeric microgripper based on the cascaded V-shaped electrothermal actuators, ionic polymer actuators, wideband actuators and energy harvesters, electromagnetic actuators and shape memory alloy actuators are comprehended. The book is structured in four sections: design, fabrication and simulation; control systems; medical applications and fault detection. Seven chapters are published following a rigorous selection process. In the first section, a study carried out to investigate experimentally and by numerical simulations a microscale plasma actuator; the design, fabrication, numerical simulations, and experimental investigations of a polymeric microgripper designed using the cascaded V-shaped electrothermal actuators; a review of the development of ionic polymer actuator with introduction of two kinds of typical polymer actuators - ionic polymer-metal composites and bucky gel actuator - with their basic principle and fabrication process and typical applications and a methodology of designing and testing wideband actuators and energy harvesters, treated as one mechanical resonator, with a discussion on shock harvester, resonant harvester and energy transmission system, are presented. The second section has a chapter dedicated to modeling, system identification and control of electromagnetic actuators with main focus on the actuators used in magnetic levitation, in fuel injection systems and in variable valve timing. The third section presents a study focused on quantifying the decline in tactile sensation associated with diabetic neuropathy and developed a measurement device that used a thin-shaped memory alloy wire as the actuator. The fourth section includes a chapter presenting a two-level fault diagnosis and root-cause analysis scheme for a class of interconnected invertible dynamic systems, which aims at detecting and identifying actuator fault and causes.

Download or read book Numerical Modeling of Microwave Plasma Actuators for Aerodynamic Flow Control written by Emanuele Arcese and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent decades, microwave discharge plasmas have attracted increasing attention of aerospace scientific community to the subject of aerodynamic flow control because of their capability of sub- stantially modifying the properties of the flow around bodies by effective energy deposition. The design and optimization of these plasma actuators as flow control technique require a compre- hensive understanding of the complex physics involved that the sole experiments are incapable to provide.In this context, we have interest in the numerical modeling of the mutual interaction of elec- tromagnetic waves with plasma and gas in order to better understand the nature of microwave discharges and their applicability. A challenging problem arises when modeling such phenomena because of the coupling of different physics and therefore the multiplicity of spatial and tempo- ral scales involved. A solution is provided by this thesis work which addresses both physics and applied mathematics questions related to microwave plasma modeling.The first part of this doctorate deals with validity matters of the physical model of microwave breakdown based on the local effective field concept. Because of large plasma density gradients, the local effective field approximation is questionable and thus a second-order plasma fluid model is developed, where the latter approximation is replaced by the local mean energy approximation. This modeling approach enables to take into account the non-locality in space of the electron energy balance that provides a more accurate description of the energy deposition by microwave plasma leading to the shock waves formation into the gas. A dimensionless analysis of the plasma fluid system is performed in order to theoretically characterize the non-locality of the introduced electron energy equation as function of the reduced electric field and wave frequency. It also discusses other approximations related to the choice and method of calculation of electron transport coefficients.Concerning the mathematical aspects, the thesis work focuses on the design and the analysis of a multiscale method for numerically solving the problem of electromagnetic wave propagation in microwave plasma. The system of interest consists of time-dependent Maxwell's equations coupled with a momentum transfer equation for electrons. The developed approach consists of a Schwartz type domain decomposition method based on a variational formulation of the standard Yee's scheme and using two levels of nested Cartesian grids. A local patch of finite elements is used to calculate in an iterative manner the solution in the plasma region where a better precision is required. The proposed technique enables a conservative local and dynamic refinement of the spatial mesh. The convergence behavior of the iterative resolution algorithm both in an explicit and implicit time-stepping formulation is then analyzed.In the last part of the doctorate, a series of numerical simulations of microwave breakdown and the filamentary plasma array formation in air are performed. They allow to study in detail the consequences of the different types of physical approximations adopted in the plasma fluid model. Then, these numerical experiments demonstrate the accuracy and the computational efficiency of the proposed patch correction method for the problem of interest. Lastly, a numerically investigation of the effects of gas heating on the formation and sustaining of the filamentary plasma array in atmospheric-pressure air is carried out. For doing this, the developed microwave-plasma model is coupled with unsteady Navier-Stokes equations for compressible flows. The simulations provide interesting features of the plasma array dynamics during the process of gas heating, in close agreement with experimental data.

Download or read book Numerical Modeling of Dilectric Barrier Discharge Plasma Actuator in Air written by Alexandre Likhanskii and published by . This book was released on 2008 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Actuators written by Constantin Volosencu and published by . This book was released on 2018 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book promotes new research results in the field of modern actuators and their applications. New coverage of dielectric barrier discharge plasma actuators, polymeric microgripper based on the cascaded V-shaped electrothermal actuators, ionic polymer actuators, wideband actuators and energy harvesters, electromagnetic actuators and shape memory alloy actuators are comprehended. The book is structured in four sections: design, fabrication and simulation; control systems; medical applications and fault detection. Seven chapters are published following a rigorous selection process. In the first section, a study carried out to investigate experimentally and by numerical simulations a microscale plasma actuator; the design, fabrication, numerical simulations, and experimental investigations of a polymeric microgripper designed using the cascaded V-shaped electrothermal actuators; a review of the development of ionic polymer actuator with introduction of two kinds of typical polymer actuators - ionic polymer-metal composites and bucky gel actuator - with their basic principle and fabrication process and typical applications and a methodology of designing and testing wideband actuators and energy harvesters, treated as one mechanical resonator, with a discussion on shock harvester, resonant harvester and energy transmission system, are presented. The second section has a chapter dedicated to modeling, system identification and control of electromagnetic actuators with main focus on the actuators used in magnetic levitation, in fuel injection systems and in variable valve timing. The third section presents a study focused on quantifying the decline in tactile sensation associated with diabetic neuropathy and developed a measurement device that used a thin-shaped memory alloy wire as the actuator. The fourth section includes a chapter presenting a two-level fault diagnosis and root-cause analysis scheme for a class of interconnected invertible dynamic systems, which aims at detecting and identifying actuator fault and causes.

Download or read book A Direct Numerical Simulation of Dielectric Barrier Discharge DBD Plasma Actuators for Turbulent Skin friction Control written by Dana Elam and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent skin-friction control is the subject of much research and the use of transverse (spanwise) oscillating motions offers the means of obtaining a significant reduction in skin-friction. Dielectric barrier discharge (DBD) actuators can be used to generate spanwise oscillating waves but the difficulty in placing a sensor in the area of plasma gives rise to problems in recording near-wall velocities. A modified version of the Shyy et al. (2002) DBD model was integrated into a direct numerical simulation (DNS). This numerical model was used in a series of two-dimensional simulations, in initially quiescent ow, and the results were compared to results reported from experimental investigations. A close affinity was found confirming that the DBD model is satisfactory. Both a temporal and a spatial, spanwise oscillating ow were investigated. Only one plasma profile was investigated. Three actuator spacings were investigated. Only the largest actuator spacing resulted in a gap between each plasma profile that was larger than the plasma profile width itself. A spatially uniform plasma configuration produced larger DR% than spanwise wall oscillation for both spatial and temporal waves, maximum DR = 51% compared to a DR = 47% for a spanwise wall oscillation. Increased skin-friction reductions originated from the displacement of the Stokes layer. The spatial wave produced lower skin-friction values than temporal waves for all the configurations. For both spatial and temporal waves the performance of the discrete configurations in producing an overall skin-friction reduction decreased with increasing actuator spacing. Using both temporal and spatial waves, the configuration with the largest spacing, which is relatively small, did not produce a drag reduction for any case that was tested.

Download or read book Numerical Simulations of Single Dielectric Barrier Discharge Plasma Actuators written by Kendal David Dennis and published by . This book was released on 2008 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Propulsion written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2021-10-13 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: What Is Plasma Propulsion A SpaceX Starship powered by chemical methylox engines will take up to six months to reach Mars. On Earth, radiation exposure is less than 2.5 milliseiverts per year. On their approach to Mars, colonists will face levels 300 times higher than that. Can we use superconducting advanced plasma propulsion technologies to cut the time down to 30 days? Neutron Star Systems has developed an improved magnetoplasmadynamic thruster system that uses rare earth barium copper oxide high temperature superconducting electromagnets to significantly improve plasma propulsion performance while consuming less electricity. This could be the way of the future for spaceflight propulsion. Technically, there are two types of propulsion systems namely chemical and electric depending on the sources of the fuel. Electrostatic thrusters are used for launching small satellites in low earth orbit which are capable to provide thrust for long time intervals. These thrusters consume less fuel compared to chemical propulsion systems. Therefore for the cost reduction interests, space scientists are interested to develop thrusters based on electric propulsion technology. Can SpaceX use Advanced Plasma Propulsion for Starship? How You Will Benefit (I) Insights, and validations about the following topics: Chapter 1: Plasma Propulsion Engine Chapter 2: Spaceflight Chapter 3: Wingless Electromagnetic Air Vehicle Chapter 4: Electrically Powered Spacecraft Propulsion Chapter 5: Ion thruster Chapter 6: Stellarator Chapter 7: Electric sail Chapter 8: MagBeam Chapter 9: Spacecraft propulsion Chapter 10: Advanced Electric Propulsion System Chapter 11: Anti-gravity Chapter 12: Artificial gravity (II) Answering the public top questions about plasma propulsion. (III) Real world examples for the usage of plasma propulsion in many fields. (IV) 17 appendices to explain, briefly, 266 emerging technology in each industry to have 360-degree full understanding of plasma propulsion' technologies. Who This Book Is For Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of plasma propulsion.

Download or read book Numerical Simulation of Aerodynamic Plasma Actuator Effects written by Débora Gleice da Silva Del Rio Vieira and published by . This book was released on 2013 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Dielectric Barrier Discharge Plasma Actuators for Flow Control Simulations written by Denis Palmeiro and published by . This book was released on 2011 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-dielectric-barrier-discharge (SDBD) plasma actuators have shown much promise as an actuator for active flow control. Proper design and optimization of plasma actuators requires a model capable of accurately predicting the induced flow for a range of geometrical and excitation parameters. A number of models have been proposed in the literature, but have primarily been developed in isolation on independent geometries, frequencies and voltages. This study presents a comparison of four popular plasma actuator models over a range of actuation parameters for three different actuator geometries typical of actuators used in the literature. The results show that the hybrid model of Lemire & Vo (2011) is the only model capable of predicting the appropriate trends of the induced velocity for different geometries. Additionally, several modifications of this model have been integrated into a new proposed model for the plasma actuator, introducing a number of improvements.

Download or read book Numerical Simulation of DBD Plasma Actuators for Flow Control written by Huw Borradaile and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Model of Channel Dielectric Barrier Discharge Actuator written by Karthik Naganathan and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma actuators are active flow control devices used for vortex generation, momentum addition, and boundary layer attachment. The advantages of plasma actuators are that they are lightweight, quick to respond, and lack moving parts. Channel Dielectric Barrier Discharge actuators are a type of dielectric barrier discharge actuators in which the exposed electrode is placed in the bulk fluid to reduce viscosity effects. There are very few models that can predict the plasma forcing with good accuracy. These models however do not account for the geometric parameters such as the width of the electrode. This thesis discusses two numerical models, one built from a surface DBD model and one built from electrostatic modeling. The modified surface DBD model predicts exit velocity profiles similar to the experimental results. But it fails to account for some geometric parameters. The electrostatic model successfully captures the potential distribution asymmetry. The forcing function obtained by curve fitting the force distribution was adjusted to give reasonable velocity distribution when implemented as a source term in the CFD solver. The adjusted ES model predicted velocity contours and Reynolds number variation with good accuracy.

Download or read book Numerical Investigation of Plasma Actuator Configurations for Flow Separation Control at Multiple Angles of Attack written by Thomas Kelsey West and published by . This book was released on 2012 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The primary objective of the study presented in this thesis was to analyze the effectiveness of aerodynamic plasma actuators as a means of active flow control over a low speed airfoil at multiple angles of attack each corresponding to two different flow separation mechanisms (i.e., laminar separation bubble and turbulent flow separation at stall conditions). Detailed parametric studies based on steady and unsteady Navier-Stokes simulations, modified to include the body force term created by the plasma actuator, were performed for a NACA 0012 airfoil at a chord Reynolds number of 105. In particular, parametric studies were performed to investigate the influence of the number, the location, the imposed body force magnitude (power input) and steady vs. unsteady operation of plasma actuators on the flow control effectiveness. First, the effectiveness of plasma actuators was studied when applied to the airfoil at a relatively low angle of attack, which involved the development of a laminar separation bubble (LSB). Next, the effectiveness of plasma actuators was analyzed at a high angle of attack where the stall of the airfoil occurs with a fully turbulent flow assumption. The results show that plasma actuators can provide significant improvement in aerodynamic performance for the flow conditions considered in this study. For LSB control, as much as a 50% improvement in the lift to drag ratio was observed. Results also show that the same improvement can be achieved using an unsteady or multiple actuators, which can require as much as 75% less power compared to a single, steady actuator. For the stalled airfoil case, as much as a 700% improvement in L/D was observed from a single, steady actuator. Note that this was achieved using a power input eight times higher than what was used for LSB control. Also, unsteady and multiple actuator configurations do not provide the same enhancement as the single, steady actuators. This was found to be due to the nature of the turbulent separation (trailing edge separation) at the stall condition that occurs for the selected airfoil and Reynolds number"--Abstract, leaf iii.

Download or read book Magneto hydrodynamics Simulation Study of High Density Thermal Plasmas in Plasma Acceleration Devices written by Hariswaran Sitaraman and published by . This book was released on 2013 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of a Magneto-hydrodynamics (MHD) numerical tool to study high density thermal plasmas in plasma acceleration devices is presented. The MHD governing equations represent eight conservation equations for the evolution of density, momentum, energy and induced magnetic fields in a plasma. A matrix-free implicit method is developed to solve these conservation equations within the framework of an unstructured grid finite volume formulation. The analytic form of the convective flux Jacobian is derived for general unstructured grids. A Lower Upper Symmetric Gauss Seidel (LU-SGS) technique is developed as part of the implicit scheme. A coloring based algorithm for parallelization of this technique is also presented and its computational efficiency is compared with a global matrix solve technique that uses the GMRES (Generalized Minimum Residual) algorithm available in the PETSc (Portable Extensible Toolkit for Scientific computation) libraries. The verification cases used for this study are the MHD shock tube problem in one, two and three dimensions, the oblique shock and the Hartmann flow problem. It is seen that the matrix free method is comparatively faster and shows excellent scaling on multiple cores compared to the global matrix solve technique. The numerical model was thus verified against the above mentioned standard test cases and two application problems were studied. These include the simulation of plasma deflagration phenomenon in a coaxial plasma accelerator and a novel high speed flow control device called the Rail Plasma Actuator (RailPAc). Experimental studies on coaxial plasma accelerators have revealed two different modes of operation based on the delay between gas loading and discharge ignition. Longer delays lead to the detonation or the snowplow mode while shorter delays lead to the relatively efficient stationary or deflagration mode. One of the theories that explain the two different modes is based on plasma resistivity. A numerical modeling study is presented here in the context of a coaxial plasma accelerator and the effect of plasma resistivity is dealt with in detail. The simulated results pertaining to axial distribution of radial currents are compared with experimental measurements which show good agreement with each other. The simulations show that magnetic field diffusion is dominant at lower conductivities which tend to form a stationary region of high current density close to the inlet end of the device. Higher conductivities led to the formation of propagating current sheet like features due to greater convection of magnetic field. This study also validates the theory behind the two modes of operation based on plasma resistivity. The RailPAc (Rail Plasma Actuator) is a novel flow control device that uses the magnetic Lorentz forces for fluid flow actuation at atmospheric pressures. Experimental studies reveal actuation ~ 10-100 m/s can be achieved with this device which is much larger than conventional electro-hydrodynamic (EHD) force based plasma actuators. A magneto-hydrodynamics simulation study of this device is presented. The model is further developed to incorporate applied electric and magnetic fields seen in this device. The snowplow model which is typically used for studying pulsed plasma thrusters is used to predict the arc velocities which agrees well with experimental measurements. Two dimensional simulations were performed to study the effect of Lorentz forcing and heating effects on fluid flow actuation. Actuation on the order of 100 m/s is attained at the head of the current sheet due to the effect of Lorentz forcing alone. The inclusion of heating effects led to isotropic blast wave like actuation which is detrimental to the performance of RailPAc. This study also revealed the deficiencies of a single fluid model and a more accurate multi-fluid approach is proposed for future work.

Download or read book Body Force of Plasma Actuator with Different Operating Conditions Using Phase resolved Approach written by Venur Tejas Alva and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma actuators are electric devices that can generate a flow of air without any moving parts. The salient feature of a plasma actuator is its ability to impart a body force in the region of the ionized air. The force produced is unsteady. A phase-resolved determination of force distribution is important to develop models that better approximate physical conditions for use in numerical simulations and design. Phase resolved study of the body force generated by the plasma actuator is performed experimentally using Particle Image Velocimetry. The primary objective of the present work is to study the ability of plasma actuators to transfer momentum to the air and the contribution of terms in the momentum equations used to compute the body force from the planar flow field measurements. The spatial and temporal evolution of the effect of the forcing by the actuator has been discussed with emphasis on the acceleration term.

Download or read book Numerical Simulation of Plasma based Actuator Vortex Control of a Turbulent Cylinder Wake written by Nathan Keith McMullin and published by . This book was released on 2006 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical study has been performed to investigate the mechanics of the turbulent wake of a circular cylinder that is controlled by a plasma actuator. The numerical investigation implements a straightforward moving wall boundary condition to model the actuator's effects on the flow. Validations of the moving wall for this simulation are set forth with the understanding that the moving wall can model the plasma actuator bulk flow effects at a distance downstream and not in a region near or on the plasma actuator. The moving wall boundary condition is then applied to a circular cylinder at a Reynolds number of 8,000. At this unsteady transitional flow regime, a large eddy simulation solver is utilized to resolve flow features. The moving walls are placed at the top and bottom ninety degree points of the cylinder and alternately activated at a frequency to produce lock-in behavior. Investigation into the flowfield mechanics reveals that a harmonic frequency of the forced frequency occurs from the creation of sub-vortices from the instantaneous starting and stopping of the moving-wall actuators. With the forcing frequency close to the natural shedding frequency it is found that the aerodynamic drag increases due to the moving wall creating an average low pressure region on to the downstream side of the cylinder. It is also found that drag can be reduced when the forcing frequency is closer to half the natural shedding frequency. This happens because of a decrease in the average pressure on the downstream side of the cylinder.