Corona, Dielectric Barrier and Sliding Discharges in the Flow Control and Environmental Protection: From Fundamental Studies to Optimization of Practical Devices

工业、医学和环境保护中的许多过程都涉及气体中的放电。对我们的社会来说，最重要的设备可能是静电除尘器，它可以去除许多工业过程中产生的灰尘颗粒，使我们可以呼吸更清洁的空气。许多有毒物质也可以通过这种方法分解。所有这些都是可能的，因为气体放电产生自由离子和活性化学物质。尘埃颗粒可以带电，它们的运动可以使用电力控制，确保它们被收集，而不是被释放到大气中。 在气体放电中产生的移动离子也可以由于与中性分子的频繁碰撞而产生气体运动，这通常被称为二次电流体动力学流或离子风。此外，从离子到气体分子的能量转移可以局部地增加它们的温度，产生冲击波，这也影响气体流动。基于气体放电的实际设备的设计和优化需要对过程有透彻的理解，并能够预测过程的所有电气，化学，热和空气动力学特性。 拟议的研究计划的第一个目标是创建一组数值算法，它可以用来模拟电晕，介质阻挡和滑动放电，假设不同的参数的过程：几何形状的放电间隙，极性和波形的供应电压，温度，压力和环境气体的组成。之后，根据所需的精度和可用的计算资源，可以使用适当的模型来研究不同的设备。商业软件包不能解决这个问题;它们通常是发散的，或者至少表现出很大的数值扩散。 有一个可靠的模拟工具，它将有可能调查和优化三个重要的实用设备：气体放电致动器控制流动边界层，电流体动力干燥机的有机物质，和静电除尘器的亚微米颗粒。加拿大很大一部分电力是由燃煤发电站产生的，这会产生大量的灰尘。有效地收集这些灰尘对我们社会的健康至关重要，也对保护我们的环境至关重要。用于边界层控制的致动器的改进的特性可以极大地影响飞机和风力涡轮机工业。

Many processes in industry, medicine and environmental protection involve electrical discharges in gases. The most important devices for our society are probably electrostatic precipitators, which remove dust particles generated in many industrial processes so we may breathe cleaner air. Many toxic substances can also be decomposed using this process. All this is possible, because gas discharges produce free ions and active chemical species. The dust particles can be electrically charged and their motion can be controlled using electric forces, ensuring they are collected and instead of being released into the atmosphere. Moving ions generated in gas discharges can also produce gas motion due to frequent collisions with neutral molecules this is commonly called the secondary electrohydrodynamic flow, or ionic wind. Moreover, the energy transfer from ions to gas molecules can locally increase their temperature producing a shock wave, which also affects the gas flow. The design and optimization of practical devices based on gas discharges require a thorough understanding of the process and ability to predict all electrical, chemical, thermal and aerodynamic characteristics of the process. The first objective of the proposed research program is to create a set of numerical algorithms, which can be used to simulate the corona, dielectric barrier and sliding discharges, assuming different parameters of the process: geometry of the discharge gap, polarity and waveform of the supplied voltage, and temperature, pressure and composition of ambient gas. Later, appropriate models can be used to study different devices, depending on the required accuracy and available computing resources. Commercial software packages are not able to solve this problem; they are usually divergent, or at least exhibit a large numerical diffusion. Having a reliable simulation tool, it will be possible to investigate and optimize three important practical devices: a gas discharge actuator for controlling the flow boundary layer, electrohydrodynamic dryers of organic substances, and electrostatic precipitators for submicron particles. A large percentage of power in Canada is generated by coal-fired power stations, which produce enormous amounts of dust. Efficient collection of this dust is of paramount importance for the health of our society, but also to protecting our environment. Improved characteristics of actuators for the boundary layer control can tremendously affect aircraft and wind turbine industries.