Gabriele Neretti

University of Bologna | UNIBO · "Guglielmo Marconi" Department of Electrical, Electronic and Information Engineering DEI

We introduce a fluid computational model for the numerical simulation of atmospheric pressure dielectric barrier discharge plasmas. Ion and neutral species are treated with an explicit drift diffusion approach. The Boltzmann relation is used to compute the spatial distribution of electrons as a function of the electrostatic potential and the ionic...

Nowadays, the majority of the processes used to sterilize disposable medical devices have several drawbacks in terms of safety, energy consumption, and costs. In this work, a sterilization method based on an indirect nonthermal plasma treatment is presented. The main advantages of this method are low environmental impact, absence of harmful chemica...

Atmospheric-pressure plasma treatments for industrial and biomedical applications are often performed using Dielectric Barrier Discharge reactors. Dedicated power supplies are needed to provide the high voltage frequency waveforms to operate these nonlinear and time-dependent loads. Moreover, there is a growing technical need for reliable and repro...

This paper presents recent activities covering different plasma fields, from both theoretical and experimental point of views. An overview of the present interests of the scientific community is reported here. Starting from a brief description of the role of collisions in astrophysical plasmas, some fundamental aspects of gas discharges modelling,...

This paper presents recent activities covering different plasma fields, from both theoretical and experimental point of views. An overview of the present interests of the scientific community is reported here. Starting from a brief description of the role of collisions in astrophysical plasmas, some fundamental aspects of gas discharges modelling,...

Charge particles can increase the biocidal efficacy of nonthermal plasmas in indirect treatments. The aim of this study is to increase the amount of free charges produced and delivered by a surface dielectric barrier discharge fluid‐dynamics actuator. Different linear actuators and supplying conditions have been considered. Actuators were utilized...

In this paper, an investigation on an annular Plasma Synthetic Jet Actuator (PSJA) utilizing a Surface Dielectric Barrier Discharge (SDBD) is reported. The work is focused at an investigation of the electric charges transported by the jet produced by the actuator and deposited on a target. Particularly, an assessment of the various factors that may...

In this paper, a multi-stage numerical methodology for the description of the Dielectric Barrier Discharge physics in air is discussed. The behavior of the heavy species is computed using drift-diffusion equations. Electrons are taken into account by solving a non-linear formulation of electrostatics. The physical effects of the steamer discharges...

In this paper a high-voltage sinusoidal power supply controlled by Arduino DUE micro-controller is described. This generator can feed a dielectric barrier discharge (DBD) load with sinusoidal voltages up to 20 kV peak and frequencies in the range 10–60 kHz, with a maximum output power of 200 W. Output voltage can be produced either in a continuous...

To investigate ozone yield limit in low temperature plasmas, a detailed thermodynamic model is developed to calculate theoretical ozone yield for the first time. Theoretical ozone yield is calculated both from overall reaction and detailed reactions. In the former case, the highest theoretical ozone yield of 1211 ± 2 g kWh⁻¹ is obtained when final...

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In this study we examine both the effect of changing the applied voltage waveform shape and the modulation on-time on the amount of ozone dissolved within a liquid in a dielectric barrier discharges (DBD) bubble reactor. In this device, the discharge forms at the gas–liquid interface allowing for effective transfer of the plasma effluent into the l...

Understanding the production mechanisms of ozone and other reactive species in atmospheric pressure dielectric barrier discharges (DBDs) has become increasingly important for the optimization and commercial success of these plasma devices in emerging applications, such as plasma medicine, plasma agriculture, and plasma catalysis. In many of these a...

This paper reports the characterization of a low-power, atmospheric pressure plasma source developed for and successfully tested in applications of plasma medicine. The source produces plasma by ionizing a helium flow, containing traces of air. The effluent gas is thus enriched in reactive oxygen and nitrogen species as well as helium metastable ex...

Plasma synthetic jet actuators (PSJAs) demonstrated their ability to produce a tubular flow normal to the surface where the Dielectric Barrier Discharge (DBD) is ignited. These fluid-dynamics actuators enhance the delivery of reactive and charged species toward the target to be treated. In this work the efficacy of an octagonal PSJA used to indirec...

Annular plasma synthetic jet actuators demonstrated their ability to produce a tubular flow normal to the surface where the dielectric barrier discharge (DBD) is ignited. These fluid-dynamic actuators enhance the delivery of reactive species towards the target to be treated. In these actuators, long life charged particles are generated within the p...

In this work ozone concentration in a plane-to-plane Dielectric Barrier Discharge (DBD) reactor has been evaluated both experimentally and numerically. The reactor geometry has been chosen to generate a homogenous discharge. Therefore, simplified approaches for both experiments and numerical simulations have been utilized. The discharge was excited...

A new bench-top reactor employing a streamer discharge in air was developed and tested for potential use in an advanced oxidation stage in water treatment processes. The complex heterogeneous system and the ensuing chemical processes were characterized using an integrated approach to map the morphology of the plasma/gas/liquid interface, identify t...

This study presents a novel technique to inactivate coccidian oocysts in an aqueous solution. The technique consists in treating the contaminated liquid by using an atmospheric-pressure air Dielectric Barrier Discharge (DBD) plasma in contact with it. Many experiments in several operating conditions were performed. The discharge was supplied by sin...

This paper reports on the effects of a series of fluid-dynamic dielectric barrier discharge plasma actuators on a NACA0015 airfoil at high angle of attack. A set of jet actuators able to produce plasma jets with different directions (vectoring effect) and operated at different on/off duty cycle frequencies are used. The experiments are performed in...

In this work a low-temperature plasma source for the generation of plasma activated water (PAW) is developed and characterized. The plasma reactor was operated by means of an atmospheric-pressure air dielectric barrier discharge (DBD). The plasma generated is in contact with the water surface and is able to chemically activate the liquid medium. El...

The electrohydrodynamic (EHD) interaction induced in atmospheric air pressure by a surface dielectric barrier discharge (DBD) actuator has been experimentally investigated. Plasma synthetic jet actuators (PSJAs) are DBD actuators able to induce an air stream perpendicular to the actuator surface. These devices can be used in the field of aerodynami...

Surface dielectric barrier discharges (S-DBDs) have received renewed attention in recent years for their potential application in emerging biomedical, environmental and agricultural applications. In most of these applications, the plasma is not in direct contact with the substrate being treated and the transport of reactive species from the plasma...

Active flow control has recently received an increasing attention since it allows to directly manipulate the flow-field around a surface only when it is effectively requested. Aerodynamic plasma actuators supplied by a dielectric barrier discharge (DBD) can be used for this purpose. Usually, sinusoidal voltages in the range 5–50 kV peak and frequen...

One of the most attractive features of non-thermal plasmas is their capability to enhance chemical processes without the need of high temperatures. The Dielectric Barrier Discharge (DBD) is the most widespread type of plasma source used to obtain stable atmospheric-pressure room-temperature electrical discharges. The setup of a DBD device always in...

In this work a low temperature plasma source in aqueous environment for pathogens inactivation is characterized. The plasma reactor has been operated by means of an atmospheric pressure air Dielectric Barrier Discharge (DBD) above the water surface. The plasma has been generated by a DBD in air above a water surface. The electrodes have been suppli...

In this contribution, a poly(butylene succinate)-based copolymer containing thioether linkages (P(BS85BTDG15)) has been synthesized and characterized from the molecular, thermal and mechanical point of view. The results have been compared to the parent homopolymer. Films obtained both by PBS and P(BS85BTDG15) have been subjected to surface modifica...

In this work a novel technique to inactivate coccidian parasites in liquid environment has been investigated and implemented. A Petri dish filled with 20 ml of water contaminated by Eimeria spp. oocysts has been placed on a polished stainless steel plate connected to the high voltage source. A copper strip covered by a ceramic slab has been placed...

In this work a high voltage—high frequency generator for the power supply of a dielectric barrier discharge (DBD) plasma actuator for the aerodynamic control obtained by the electrohydrodynamic (EHD) interaction is described and tested. The generator can produce different voltage waveforms. The operating frequency is independent of the load charact...

In this work a low-temperature plasma source for the inactivation of coccidian oocysts in liquid media is characterized. The plasma reactor has been operated by means of an atmospheric pressure air Dielectric Barrier Discharge (DBD) above the water surface and in contact with it. The electrodes have been supplied by both sinusoidal and nanosecond-p...

A high-voltage high-frequency single-phase arbitrary waveform voltage generator able to supply a wide range of plasma reactors is proposed in this paper. The generator structure is based on the cascaded H-bridge multilevel topology, including 24 H-bridge basic modules with the capability of 49 output voltage levels. The individual H-bridge dc suppl...

This work reports an experimental investigation performed in wind tunnel facility on a NACA0015 airfoil equipped with a set of vectorizable fluid-dynamic DBD plasma actuators. The ability of the actuators to recover the stall condition with free stream velocities in the range 5-23 m/s has been investigated. The discharge has been generated by feedi...

In this work the development and the testing of a high voltage - high frequency plasma generator to supply Dielectric Barrier Discharge (DBD) actuators for the aerodynamic control, is reported. The generator can produce a wide set of different voltage waveforms. The peak-to-peak electrical tension is 30 kV at a frequency up to 20 kHz. The operating...

A high-voltage high-frequency arbitrary waveform voltage generator able to supply a wide range of plasma reactors is proposed in this paper. The generator structure is based on the cascaded H-bridge multilevel topology, including 24 H-bridge basic modules with the capability of 49 output voltage levels. The individual H-bridge dc supply (600V) is p...

The Electro-Hydro-Dynamics (EHD) interaction, induced in atmospheric pressure still air by a surface dielectric barrier discharge (DBD) actuator, had been experimentally studied. A plasma aerodynamic actuator array, able to produce a vectorized jet, with the induced airflow oriented toward the desired direction, had been developed. The array was co...

The Electro-Hydro-Dynamics (EHD) interaction induced by a surface dielectric barrier discharge in the aerodynamic boundary layer at one atmosphere still air has been investigated. Three different geometrical configurations of the actuator have been utilized. In the first configuration, an electrode pair separated by a 2 mm dielectric sheet has been...

The electric potential distribution induced on the surface of an aerodynamic plasma actuator, operating by means of a surface dielectric barrier discharge (DBD), has been studied both numerically and experimentally. Three actuators made with three different dielectric materials (Teflon, Plexiglas, and glass) have been used. The geometric configurat...

This paper deals with the experimental investigation on the MHD (magneto-hydro-dynamic or magneto-fluid-dynamic) interaction around a test body immersed into a hypersonic unseeded air flow. The experiments have been carried out in the CIRA plasma wind tunnel SCIROCCO. Two test conditions have been utilized for the experiments with a total pressure...

This summary paper is related to the experimental investigation on the magneto fluid dynamic interaction around a blunt test body immersed into a hypersonic unseeded air flow. The experiments have been carried out in the CIRA owned plasma wind tunnel SCIROCCO. Two test conditions have been utilized for the experiments, with a total pressure of 2.5...

This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the intera...

Summary form only given. The paper considers the charge deposited on the surface of a plasma dielectric barrier discharge (DBD) actuator. The actuator is utilized to induce the electro-hydro-dynamic (EHD) interaction in the aerodynamic boundary layer of one atmosphere air [1,2]. The effect on the EHD interaction of the charge distribution on the ac...

This paper deals with the measurements performed to characterize the jet produced by the plasma wind tunnel SCIROCCO. The measurements are aimed to determine the vibrational temperature and the electron density of the plasma flow. A numerical rebuilding of the expansion trough the nozzle has then been performed. The work is part of an experimental...

The Electro-Hydro-Dynamics (EHD) interaction, induced by a dielectric barrier discharge (DBD) in the aerodynamic boundary layer induced in a one atmosphere still air, has been studied both numerically and experimentally. Three different geometrical actuator configurations have been used. The first one is constituted by an electrode pair separated b...

In this paper, several planar dielectric barrier discharge fluid-dynamics actuators have been experimentally investigated. The actuator is made by an electrode pair separated by a dielectric. It is characterized by a planar geometry, and it induces a volume force on the gas above it which modifies the fluid dynamics within the aerodynamic boundary...

The operation of a surface dielectric barrier discharge actuator for airflow control has been experimentally investigated. The actuator is constituted by an electrode pair separated by a dielectric Teflon sheet. Several ac supply conditions have been utilized. An electrohydrodynamics interaction was induced in still air, and several fluid-dynamic r...

A Test campaign in the frame of the ASI (Italian Space Agency) funded project CAST (Advanced Aerothermodynamic Configurations for Space Transport) was performed at the CIRA GHIBLI plasma wind tunnel. The CAST Test campaign in GHIBLI consisted of more than 20 test cases including Probe measurements, microwave absorption measurements and a MHD experi...

This paper is focused on the plasma diagnostics utilized for the characterization of a hypersonic nitrogen flow. The nitrogen flow has been utilized for a test campaign on Magneto Fluid Dynamics interaction in the frame of the ASI (Italian Space Agency) funded project CAST (Advanced Aerothermodynamic Configurations for Space Transport). Microwave a...

An advanced flow control experiment, concerning magnetohydrodynamics (MHD) interaction over a blunt body, has been designed by Alta, CIRA and Department of Electrical Engineering (DIE) of University of Bologna and to be realized in CIRA's plasma wind tunnel "Scirocco" under a technology research program (TRP) funded by the European Space Agency (ES...

This paper deals with the design of an experiment devoted to MHD flow control, to be performed in CIRA GHIBLI hypersonic facility. The criteria utilized to define the proper test conditions and to design and realize the model are here described. The expansion in the nozzle has been investigated through numerical simulations in order to have a preli...

This paper gives an overview of the experimental work on the MHD-hypersonic flow interaction, carried out in the High Enthalpy Arc Heated hypersonic wind Tunnel of Alta, Pisa, Italy, in cooperation with the Department of Electrical Engineering of the University of Bologna, under the support of The European Space Agency and the Italian Space Agency....

This paper describes the results of an experimental investigation on the effect of the MHD interaction in the plasma of the shock layer above a test body immersed into a hypersonic Argon flow. The hypersonic flow was obtained by means of the high-enthalpy arc-heated wind tunnel of Alta SpA at Mach 6 and Mach 15. An extensive activity was carried ou...

This paper describes the results of an experimental investigation on the effect of the MHD interaction in the plasma of the shock layer above a test body immersed into a hypersonic Argon flow. The hypersonic flow was obtained by means of the high-enthalpy arc-heated wind tunnel of Alta SpA at Mach 15. An extensive activity was carried out in order...

A new Mach 9 contoured nozzle to use with air was designed and realized at Alta SpA with the aim to produce a uniform core flow with a diameter of at least 80 mm. The design was iteratively carried out using engineering codes and CFD simulations by CIRA. The characterization activity was carried out mapping the complete test section in terms of pit...

Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their ma...

The magnetohydrodynamics interaction around a conical test body in a hypersonic argon flow is experimentally investigated. The hypersonic flow is realized in the high-enthalpy arc-heated wind tunnel of Alta Societa per Azioni (S.p.A.) (Pisa, Italy) at Mach 6. The aim of experimental activity is to produce an experimental data base to be used for th...

The MHD interaction around a conical test body in a hypersonic argon flow was experimentally investigated. The aim of the experiment was to produce a database to be used for the validation of numerical codes for the analysis and simulation of the magnetofluid dynamics in hypersonic flows. In these experiments, the flow was obtained in the High-Enth...

In the present work an experimental investigation on the electrohydrodynamic (EHD) interaction effect, induced by means of a dielectric barrier discharge on a 1 atm subsonic air flow, is described. The air flow is obtained in an open circuit blowing wind tunnel at different air speeds. A plane plasma panel equipped with a dielectric discharge barri...

Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on DC or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their ma...

The In the present work an experimental investigation on the EHD interaction effect, induced by means of a dielectric barrier discharge on a one atmosphere subsonic air flow, is described. The air flow is obtained in an open circuit blowing wind tunnel at different air speeds. A plane plasma panel equipped with a dielectric discharge barrier system...

The MHD interaction around a conical test body in a hypersonic argon flow is experimentally investigated. The aim of the experiment is to produce a data base to be used for the validation of numerical codes for the analysis and the simulation of the magneto-fluid dynamics in hypersonic flows. In these experiments the flow is realized in the high-en...

Asymmetric DBD plasma actuator for flow control has been studied both numerically and experimentally. A comprehensive kinetic model for asymmetric DBD actuators in air has been developed. A new approach for non-intrusive diagnostic of plasma actuator induced flows in quiescent gas was proposed. The schlieren technique, burst mode of plasma actuator...