A parallel 2D code for modeling nanosecond surface dielectric barrier discharge (nSDBD), combining a discharge description, detailed kinetics and hydrodynamics, is developed and validated. A series of experiments and numerical modeling for a single pulse nSDBD in atmospheric pressure air at a voltage amplitude of 24 kV have been performed. The measured and calculated velocity of the discharge front, electrical current, 2D map of N 2 ( ) emission and hydrodynamic perturbations caused by the discharge on the time scale μ s are compared. The data are presented and analyzed for the negative and positive polarity of the streamers. A set of parametric calculations with different dielectric permittivities and different dielectric thicknesses is presented.
1 December 2018 in Plasma Sources Science and Technology
The effect of heat release in reactions with charged and electronically excited species, or so-called fast gas heating (FGH), in nanosecond surface dielectric barrier discharge (nSDBD) in atmospheric pressure air is studied. Two-dimensional numerical simulations based on the PArallel Streamer Solver with KinEtics code are conducted. The code is based on the direct coupling of a self-consistent fluid model with detailed kinetics, an efficient photoionization model, and Euler equations. The choice of local field approximation for nSDBD modeling with simplified kinetics is discussed. The reduced electric field and the electron density are examined at both polarities for identical high-voltage pulses 24 kV in amplitude on a high-voltage electrode and 20 ns full width at half maximum. The distribution of the FGH energy and the resulting gas temperature field are studied and compared with findings in the literature. The input of different reactions to the appearance of hydrodynamic perturbations is analyzed.
16 August 2013 in Journal of Physics D: Applied Physics
A two-dimensional air plasma kinetics model (16 species and 44 processes) for nanosecond discharge under atmospheric pressure was developed to reveal the spatial and temporal distribution of discharge characteristics of a surface dielectric barrier discharge (SDBD) actuator. An energy transfer model, including two channels for energy release from external power source to gas, was developed to couple plasma with hydrodynamics directly in the same dimension. The governing equations included the Poisson equation for the electric potential, continuity equations for each species, electron energy equations for electrons taking part in reactions, and Navier–Stokes equations for non-isothermal fluid. The model was validated through current–voltage profile and electron temperature obtained from experiments. Calculations for discharge characteristics as well as the responses of fluid field from tens of nanoseconds to tens of seconds were performed. Results have shown that local air is heated to 1170 K within tens of nanoseconds and then decreases to 310 K at the end of a discharge period. 30% of the total power is transferred from electric field to electrons while only 20% of this energy is then released to gas through quenching processes. 9% of the total energy is released through ion collision. A micro-shock wave is formed and propagates at the speed of sound. High local density gradient and dynamic viscosity induces vortexes which whirl the heated air downstream. The combined effects of heating convection and vortexes in repetitive pulse discharges lead to the formation of a steady jet, in agreement with experimental results.
1 July 2021 in Plasma Sources Science and Technology
For a long period, there was a resolution gap between numerical modeling and experimental measurements, making it hard to conduct a direct comparison between them, but they are now developing in parallel. In this work, we numerically study diffusive ionization wave and fast ionization wave discharge experiments using recently published electric-field-induced second-harmonic (E-FISH) data together with a classical fluid model. We propose a pressure- E / N range for the drift diffusion approximation and a pressure-grid range for the local field/mean energy approximation of the fluid model. The three-term Helmholtz photoionization model is generalized using parameters given for N 2 , O 2 , CO 2 , and air. The capabilities of the classical fluid method for modeling the inception, propagation, and channel breakdown stages are studied. The calculated electric field evolution of the ionization is compared with E-FISH measurements in the discharge development and gap-closing stages. The influence of electrode shape and predefined electron density on the streamer morphology and the long-standing inception problem of the ionization waves are discussed in detail. Within the application range of the classical fluid model, good agreement can be achieved between calculation and measurement.
23 January 2020 in Journal of Physics D: Applied Physics
The characteristics of nanosecond-pulsed dielectric barrier discharge (nSDBD) in an anti-icing configuration is studied. The mechanisms and energy characteristics of the nSDBD-based plasma-assisted anti-icing are analyzed using a numerical model and existing experimental data. Two-dimensional simulations based on PASSKEy (PArallel Streamer Solver with KinEtics) code are conducted. The code couples a self-consistent fluid model with detailed kinetics, an efficient photo-ionization model, Euler equations and a heat transfer equation for solid materials. The results of icing wind tunnel experiments conducted by two groups are analyzed together. The reduced electric field and the electron density are examined for high-voltage pulses with 800 ns and 20 ns width. The ‘merge’ of counter-propagating surface streamers with the same polarity is numerically observed under high-voltage amplitude. The effects of gas heating and solid heating in time scales of one pulse and one duty cycle are compared, and the key mechanism for icing prevention is direct fast gas-heating energy transfer from gas to ice/water accumulated on the surface in each duty cycle.
1 September 2020 in Plasma Sources Science and Technology
The streamer-to-spark transition in a point-to-plane configuration in atmospheric pressure air is studied using a 2D–0D combined approach. A validated fluid code is used and improved to model the spark stage. 2D modeling of discharges at three different temperatures, 300, 600 and 800 K, are conducted; the spark transition occurs when the temperature reaches 800 K in the first pulse. A conservative criteria of spark transition temperature is proposed based on analytical solution and compared with experiments. Kinetics modeling of the post discharge stage is conducted with consistent input values extracted from the 2D model. Results show that the streamer-to-spark transition can be initiated at a lower temperature (600 K) and lower field (50–75 Td), and the long-lifetime O-atoms formed in previous pulses play an important role in ‘knocking off’ the electrons from negative charged species and maintaining the electron density in the post discharge stage. The dominating processes for electron production are electron detachment reactions from , and O − . The ionizations from excited species only accelerate the production of electrons when the plasma is already dense.