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 charge density. This technique, widely used to speed up particle and fluid models for low-pressure conditions, poses several numerical challenges for high-pressure conditions and large electric field values typical of applications involving atmospheric-pressure plasmas. We develop a robust algorithm to solve the non-linear electrostatic Poisson problem arising from the Boltzmann electron approach under AC electric fields based on a charge-conserving iterative computation of the reference electric potential and electron density. We simulate a volumetric reactor in dry air, comparing the results yielded by the proposed method with those obtained when the drift diffusion approach is used for all charged species, including electrons. We show that the proposed methodology retains most of the physical information provided by the reference modeling approach while granting a substantial advantage in terms of computation time.

The functionality of buried metallic pipelines can be compromised by the electrical lines that share the same right-of-way. Given the considerable size of shared corridors, computer simulation is an important tool for performing risk assessment and mitigation design. In this work, we introduce an open-source computational framework for the analysis of electromagnetic interference on large earth-return structures. The developed framework is based on FLARE—an efficient finite element solver developed by the authors in MATLAB^®. FLARE includes solvers for problems involving static electric and magnetic fields, and DC and time-harmonic AC currents. Quasi-magnetostatic transient problems can be studied through time-marching or—for linear problems—with an efficient inverse-Laplace approach. In this work, we succinctly describe the optimization of time-critical operations in FLARE, as well as the implementation of a transient solver with automatic time-stepping. We validate the numerical results obtained with FLARE via a comparison with the commercial software COMSOL Multiphysics^®. We then use the validated time-marching analysis results to test the accuracy and efficiency of three numerical inverse-Laplace algorithms. The test problem considered is the assessment of the inductive coupling between a 500 $\mathrm{k}$$\mathrm{V}$ transmission line and a metallic pipeline buried in the soil.

In recent years, the use of HVDC cables has grown exponentially. One of the main challenges that remains concerns the space charge accumulation inside the insulating materials. A better understanding of the mechanisms governing this phenomenon is essential to improve the performance of HVDC systems. Numerical simulations are often employed to achieve this goal. For this reason, it is important to perform them in an efficient way. In this work, we test several numerical techniques, aiming to assess which one is the best to use for fast and reliable simulations. We consider a well-known bipolar dynamic model from the literature for our simulations. The model considers a single level of deep traps and is implemented in a one-dimensional Cartesian coordinate system, considering a thin specimen of polymeric material. We compare three different time discretization methods: a fully explicit, a semi-implicit, and a fully implicit approaches. For the advective flux discretization, we compare the first-order upwind scheme (FOU) with a second-order upwind scheme coupled with the Koren flux limiter (SOU/KL). Regarding the computation of the polarization current, we introduce a simple approach using Sato’s equation and compare it with the well-established approach based on the total current density.