Abstract Over the last ten years, expansion of atmospheric pressure plasma solutions for surface treatment materials has been remarkable, however direct technology thin film deposition needs still great effort. The objective this paper is to establish state art on scientific and technologic locks, which have be opened consider plasma‐enhanced chemical vapor (AP‐PECVD) a viable option industrial application. Basic principles understand optimize an AP‐PECVD process are summarized. Laboratory...

This paper is a state of the art understanding on physics homogeneous dielectric barrier discharges at atmospheric pressure. It based analysis present and previous work about behavior these conditions to get them. Mechanisms controlling homogeneity during gas breakdown discharge development are successively discussed. The has be Townsend one, ionization slow enough avoid large avalanche development. During breakdown, related ratio secondary emission cathode (γ coefficient) in bulk (α...

The electrical characteristics of homogeneous dielectric barrier discharges in helium, argon and nitrogen are presented discussed. From the evolution discharge current as a function voltage applied to gas it is shown that (i) helium argon, during increase, transits from non-self-sustained Townsend then subnormal glow (atmospheric pressure discharge) (ii) ionization level too low induce localization field regime cannot be achieved. discharge). this specific described including time variation...

This work is a contribution to the understanding of mechanisms controlling transition from Townsend filamentary dielectric barrier discharge when power increases. The approach consists in developing an electrical model and supply study interaction between these two elements. main components are (i) Zener diodes whose characteristics depend on take into account effect gas density variation induced by temperature (ii) RC circuit describing memory one following which due metastables electrons...

Active flow control is based on the development of robust actuators which are reliable, small and easy to integrate. A promising actuator referred as plasma synthetic jet produces a with high exhaust velocities holds promise enabling high-speed flows. With this velocity jet, it possible reduce fluid phenomena such transition turbulence, thus making increase an aircraft's performance whilst at same time reducing its environmental impact. This produced by pulsed discharge in microcavity. In...

Abstract This work examines the functionalization of sugar maple ( Acer saccharum ) and black spruce Picea mariana wood surfaces using an atmospheric‐pressure dielectric barrier discharge in He He/HMDSO (hexamethyldisiloxane) gas mixtures. Wood samples were placed on one electrodes plasma was sustained by applying a 3.5 kV peak‐to‐peak voltage at 12 kHz. Analysis stability through current–voltage I – V characteristics revealed filamentary behaviour, sharp contrast with homogeneous obtained...

Recent aircraft designs increasingly use electrical systems with higher voltages. This can lead to the occurrence of partial discharges. Testing for these phenomena is relatively poorly documented in comparison other standardized tests available aerospace components. After having investigated effect temperature, pressure, and moisture on discharge inception voltage as well characteristics, we focused environmental parameters behaviour energy dissipated by discharges polyimide film endurance...

Abstract The barrier discharges in CO2 are investigated using optical emission spectroscopy and electrical measurements, with support of spatially one-dimensional fluid modelling. study is focused on a sinusoidal driven atmospheric pressure Townsend discharge (APTD) single- multi-filament at pressure. spectra weak UV- VIS-NIR range recorded. selected vibrational spectral bands analysed the E/N determined developed intensity ratio method kinetic data available literature. technique...

One of the objectives ONERA internal project PUMA (Plasmas Used to Master Aerodynamics), is improve knowledge plasma actuators and develop new concepts for modifying and/or controlling aerodynamic phenomena. In this paper we present an experimental approach quantify effect cold on a laminar flat plate boundary layer in order evaluate turbulent transition. The presents results obtained with two types actuators, generated ionic wind characteristics velocity profiles modified by wind. Moreover...

In this paper, two-photon absorption laser induced fluorescence spectroscopy is used to follow the nitrogen atom density in flowing dielectric barrier discharges fed with pure and operating at atmospheric pressure. Two different discharge regimes are investigated: Townsend regime, which homogeneous although pressure, more common filamentary regime. both regimes, densities as high 3×1014∕cm3 detected. However, N atoms kinetic formation depends on The saturation level reached rapidly a...

Optical emission spectroscopy (OES) measurements coupled with a collisional-radiative model were used to characterize plane-to-plane dielectric barrier discharge at atmospheric pressure operated in nominally pure helium. The predicts the population densities for n = 3 levels of He excited by electron impact processes from either ground or metastable states and takes into account excitation transfer between as well all relevant radiative decays quenching reactions. Time-resolved OES indicate...

This work examines the growth dynamics of TiO2-SiO2 nanocomposite coatings in plane-to-plane Dielectric Barrier Discharges (DBDs) at atmospheric pressure operated a Townsend regime using nebulized TiO2 colloidal suspension hexamethyldisiloxane as precursors. For low-frequency (LF) sinusoidal voltages applied to DBD cell, with voltage amplitudes lower than one required for discharge breakdown, Scanning Electron Microscopy silicon substrates placed on bottom electrode reveals significant...

The aim of this paper is to improve the understanding mechanisms controlling uniformity thin films made by atmospheric pressure plasma enhanced chemical vapour deposition (AP-PECVD). To reach goal, influence gas flow-rate and injection design on film thickness studied through experiments numerical simulation in case silica-like layers deposited from silane nitrous oxide using a nitrogen Townsend dielectric barrier discharge. Results show that whatever flow-rate, when injected uniformly...

Diffuse dielectric barrier discharges are generated over a very wide range of frequencies. According to the targeted frequency, glow, Townsend-like, hybrid, Ω and RF-α modes sustained. In this paper, electrical characterization discharge cell together with an model used estimate electron density from current voltage measurements for excitation frequencies ranging 50 kHz 15 MHz. The is found vary 1014 1017 m−3 frequency range. addition, collisional-radiative coupled optical emission...

This work focuses on the investigation of memory effect origin in atmospheric pressure Townsend discharges nitrogen/oxidizing gas mixtures. For this purpose, an experimental approach is used a plane-to-plane dielectric barrier discharge, using short exposure time photographs discharge with interference filters, synchronized current. A segmented electrode into eight strips allows to correlate current and light emissions from different species space (position along flow). The results highlight...

Abstract This work focuses on a diffuse Dielectric Barrier Discharge (DBD) in atmospheric pressure air using an original experimental approach. In air, the role of capacitance discharge regime has not yet been studied even though it affects current. To address this gap knowledge, dielectric was modified by means thickness plane-to-plane DBD configuration. The analyzed short exposure time photographs and electrical measurements order to remove any potential uncertainties regarding nature air....

The plasma synthetic jet, which produces a jet with high exhaust velocities, is very attractive for aerodynamic purposes. aim of this paper to illustrate how the size discharge (evaluate using short-exposure-time pictures discharge) influences velocity (determined through use Schlieren images).

Nanocomposite thin films can be obtained by polymerization of a colloidal solution in dielectric barrier discharge (DBD) at atmospheric pressure. In such process, the dispersion nanoparticles into matrix is driven charging, transport, and deposition dynamics atomized colloid. This work examines interaction TiO2 with ac electric fields plane-to-plane reactor. Experiments are performed off to examine transport phenomena over wide range experimental conditions fixed particle charge...

A combination of optical emission spectroscopy and collisional-radiative modelling is used to determine the time-resolved electron temperature (assuming Maxwellian energy distribution function) number density Ar 1s states in atmospheric pressure Ar-based dielectric barrier discharges presence either NH3 or ethyl lactate. In both cases, Te values were higher early discharge cycle (around 0.8 eV), decreased down about 0.35 eV with rise current, then remained fairly constant during extinction....

The aim of this paper is the modeling a dielectric barrier discharge at atmospheric pressure, in Townsend regime. This model based on an equivalent electrical circuit. It takes into account main physical phenomena discharge. allows to have general view process and study influence power supply also interesting tool for design optimization.

Abstract This work investigates the effects of process parameters on thin-film deposition by direct liquid injection in a low-frequency dielectric barrier discharge. The precursor, hexamethyldisiloxane, is introduced as micrometer-size droplets with nitrogen carrier gas pulsed mode and discharge produced at atmospheric pressure regime. No significant deposit observed during plasma-off time outside region. Despite injection, this reveals that precursor content plasma zone remains constant...

The requirements of nanocomposite thin films, having non-aggregated nanoparticles homogeneously dispersed in the matrix, have been realized using a new method Direct Liquid Reactor-Injector (DLRI) nanoparticles. In this approach, unlike conventional aerosol-assisted plasma deposition, are synthesized before their injection as an aerosol into plasma. our experiments, we used two different reactors, namely asymmetric low-pressure RF reactor and parallel plate dielectric barrier discharge at...