Numerical study of ElectroAeroDynamic force and current resulting from ionic wind in emitter/collector systems

Abstract

ElectroAeroDynamic (EAD) propulsion has recently shown a growing interest with distinct propulsive capabilities and specific advantages. These experimental observations are therefore driving interest for numerical predictions of their propulsive capabilities. Keeping with a drift region description associated with Kaptzov approximation of the corona discharge region effect, we evaluate the detailed contributions of EAD forces from electro-drift effects computation only. We propose a new regularization procedure for the numerical formulation of the electro-drift problem, allowing the convergence of the resulting iterative procedure (here a Newton method) over very large domains, using iterative adapted meshes in high gradient regions. Our predictions show a good comparison with many experimental configurations, both for the current/intensity and the propulsive force. In some cases, we identify the air drag and the Kaptzov approximation to explain discrepancies with experimental measurements. Finally, we confirm optimal configurations for staggered emitters and collectors arrays, consistently with previously reported experimental results.

Multi-scale two-domain numerical modeling of stationary positive DC corona discharge/drift-region coupling

“…This approach is very close to the one described by Feng [13] as well as more recently in [27] except for an additional proposed regularization. There is however a difference: the boundary condition for the ion transport equation is specified as a flux instead of a prescribed Dirichlet value.…”

“…Finally, in the following, we will not solve the electron problem in the drift domain 2 , but, for now, we leave it as in (27), but for neglecting the contribution of the αef term which is O ( exp(−1/ ) ), without expanding it in , i.e.…”

“…Considering non axisymmetric drift region problems whilst using axi-symmetric charge injections and/or electric potential (such as Peek's law) has also been used (e.g. in point/plane configuration [26], cylinder/cylinder configurations [27], etc...) which might be a fair approximation is some cases. Nevertheless, in general non axi-symmetric configurations not only the parameters of currentpotential law (and/or charge injection-electric field law) have to be adapted, but also the hypothesis of axi-symmetrical emitted charges has to be reconsidered.…”

Multi-inception patterns of emitter array/collector systems in DC corona discharge

“…Consequently, different boundary conditions have to be applied on ignited and non-ignited emitters. A resolution method, extending the one of [45] but considering an assumed ignition pattern, is presented in appendix Appendix A.2. Having at hand a resolution method considering an assumed ignition pattern is still not sufficient, since for a given geometrical configuration and value of the applied voltage, the ignition pattern is not known a priori.…”

“…Section 2.1 explains how the non-linear drift-diffusion problem, is solved for multi-inception systems. This approach follows [42,43,44,16,42,45] for which a Kaptzov approximation is used for corona discharge modeling. Nevertheless, a dynamically selected boundary condition is adopted here, where either inception or non-inception is possible for every emitter.…”