Electrical and Aerodynamic Effects of Corona and Dielectric Barrier Discharges; From Numerical Models to Optimization of Practical Devices

本项目涉及电晕、介质阻挡和滑动放电的基础研究和数值模拟。虽然这两种现象的完整数学模型相当复杂，实际上不可能进行数值处理，但需要创建一个合理的简化，只涉及最重要的反应。模拟放电问题的数值算法包括两个部分：电场的计算和所有离子的输运。这是由双曲方程控制的，不能用传统的技术来解决。预计总变差递减方案可以有效地预测离子种类的时空分布，但在非结构化三角网格的版本中可以工作。所开发的算法将首先用于研究氧中电晕放电在电晕电极正负极性下的基本性质，包括光电离。然后，其他一些气体将被研究，最重要的是氮，它不是电负性气体，但有实验证据表明，特里谢尔脉冲也可以存在于这种气体中。由于对介质阻挡放电应用的广泛兴趣，我们还将开发一种数值算法。将尝试两种方法：辉光模型和脉冲模型。第一种方法是简化的，因为它是基于单一离子种类的方法，完全忽略了电离层中的过程。然而，它应该是快速的任何电极配置。脉冲模型将尝试再现单个电流脉冲，这要准确得多，但必须优化算法，以便在合理的时间内模拟整个过程。工作和验证的数值算法将用于两个实用装置的建模和优化：利用介质阻挡放电收集亚微米颗粒的静电除尘器和控制气动边界层的静电致动器。这两个课题都有少数研究团队进行了实验研究，但迫切需要建立一个数值模型，从而大大加快研究进展。

The project deals with fundamental investigation and numerical simulation of electric corona, dielectric barrier and sliding discharges. While the full mathematical model of both phenomena is rather complicated and practically impossible for numerical handling, a reasonable simplification needs to be created, which involves the most important reactions only. Numerical algorithm for simulating discharge problems involves two parts: calculation of electric field and transport of all ionic species. This is governed by hyperbolic equations, which cannot be solved using conventional techniques. It is planned that the Total Variation Diminishing schemes can be effective to predict spatial and temporal distributions of ionic species, but in the version which can work for unstructured triangular meshes. The developed algorithm will be first used to study the fundamental properties of corona discharge in oxygen under negative and positive polarities of corona electrode for the case including photoionization. Then, some other gases will be investigated, most importantly nitrogen, which is not an electronegative gas, but there is an experimental evidence that Trichel pulses can also exist in this gas. Due to widespread interest in application dielectric barrier discharge, a numerical algorithm for this phenomenon will be also developed. Two approaches will be attempted: a glow and a pulse models. First one is simplified as it is based on a single ionic species approach, which completely neglects the processes in the ionization layer. However, it should be fast for any electrode configurations. The pulse model will try to reproduce individual current pulses, which is much more accurate, but the algorithm must be optimized, so that the entire process can be simulated in a reasonable time. Working and validated numerical algorithms will be used for modeling and optimization of two practical devices: electrostatic precipitator for collecting submicrometer particles using dielectric barrier discharge and electrostatic actuator for controlling the aerodynamic boundary layer. Both topics are experimentally investigated by a few research teams, but there is an urgent need to create a numerical model, so that the research progress can be substantially accelerated.