ANEMONE: a fully three-dimensional solid-state electro-aerodynamic propulsion system simulator

TL;DR

ANEMONE provides a fully three-dimensional simulator for solid-state electro-aerodynamic propulsion by solving a three-component plasma fluid model (electrons, positive ions, negative ions) coupled to Poisson's equation $\nabla^2 \phi = -\frac{1}{\epsilon_0}(\rho_+ - \rho_- - \rho_e)$ and transforming the problem along electric-field lines using the method of characteristics and perturbation theory. It decomposes the large 3D problem into many smaller eigenvalue problems, enabling tractable computation of corona inception voltages via a nonlinear integral equation and estimation of energy conversion efficiency through $\eta = \frac{T U_{\infty}}{J V_{\mathrm{apply}}} \cdot 100\%$, validated on MIT SST and Keio HN-7 geometries. The approach leverages fully automatic hierarchical Cartesian grids, a 3D Laplace solver, and adaptive mesh refinement with PARDISO to handle multi-scale features, providing the first 3D predictions of corona onset and two key performance metrics for representative devices. The results demonstrate reasonable agreement with theory and experiments and show the potential to guide electrode design and optimization for silent, efficient drones, while acknowledging limitations such as neglect of certain space-charge interactions and a focus on the earliest discharge path.

Abstract

Solid-state electro-aerodynamic propulsion systems are devices that utilize atmospheric pressure corona discharge and have been actively researched in recent years as a means of achieving silent drones. However, these systems contain multiple, widely disparate time and spatial scales. Therefore, the governing equations of the systems, a three-component plasma fluid model that considers the presence of electrons, positive ions, and negative ions, constitute a stiff non-linear system of partial differential equations, challenging to solve. Here, we have developed an ANEMONE simulator capable of numerically estimating the corona inception voltage and energy conversion efficiency in three-dimensional solid-state electro-aerodynamic propulsion systems. Specifically, on the basis of the governing equations, we adopted the method of characteristics and the perturbation method to obtain the sub-problems. Furthermore, we have successfully obtained the integral equations, making the sub-problems easier to solve. Finally, we validated the prediction results based on the theoretical results in a previous study. Remarkably, ANEMONE is the first simulator in the world which predicted the two representative performance of fully three-dimensional propulsion systems.

Figures (8)

• Figure 1: The procedures using the fully automatic grid generation. As shown in the first figure, a typical solid-state electro-aerodynamic propulsion system consists of a pair of electrodes (the wire and collector). As shown in the second figure, an unstructured mesh with a scale of one million nodes can be generated within a few seconds even on a laptop using the proposed method (although additional computation for inter-element connectivity is also required). The third figure shows the spatial distribution of the scalar electric potential, visualized using isosurfaces of equal potential.
• Figure 2: The multiscale nature of the solid-state electro-aerodynamic propulsion systems in space.
• Figure 3: Overview of Single-Stage Thruster (SST).
• Figure 4: Overview of the HN-7 thruster.
• Figure 5: Corona inception voltage as a function of the electric field line (SST). Discharge begins at voltages below 16 kV in areas where the path is relatively short. As the discharge path extends, the corona discharge inception voltage corresponding to that path becomes relatively higher.