CWI improves discharge models for technical applications

Pulsed electric discharges have important applications, such as purifying polluted air in highway tunnels, disinfection and wound healing. As physical and chemical processes in pulsed discharges occur on a large variety of scales, it is difficult to model them. Mathematician Aram Markosyan, PhD candidate from Centrum Wiskunde & Informatica (CWI), developed better models for these discharges and designed an open source software package ‒ PumpKin ‒ to analyze the chemical reactions initiated by discharges on different time scales. On Monday, 19 May, he defended his PhD thesis 'Modeling multiple time scales in streamer discharges' at Eindhoven University of Technology. There is much interest from both industry and academia in this research.

Pulsed discharges are created by applying sudden high voltage differences to air, traffic exhaust and other gases. In short-living discharges of tens of nanoseconds, the gas isn’t hot. The electrons gain very high energies and collide with the molecules, triggering a chain of chemical reactions. These chemical products are very useful for, for instance, painless wound healing or disinfection. For both the initial and later stage of the discharge, Markosyan improved the models and simulations.

To improve the description of the first nanoseconds of the discharge, called the streamer phase, Markosyan developed a high order fluid model, together with former CWI researcher Sasha Dujko in Belgrade. For the later phases of discharges he designed – together with another former CWI researcher, Alejandro Luque in Granada - the software package PumpKin, which stands for 'Pathway reduction method for plasma kinetic models'. The researcher explains: "In air there are hundreds of components and thousands of reactions. Because of this complexity, even a simplified simulation on a supercomputer cluster takes very long; typically in the order of weeks. With our new software package, the complexity of the system can be significantly reduced, with calculation times of hours. Thanks to our automatic mathematical analysis, the results are in very good agreement with the non-simplified methods and with experiments. This is a great improvement, both in time and in quality - also compared to commercial software packages."

The research results can be used to describe the chemical composition of the atmosphere in climate research, for plasma research, for the design of high-voltage switches and for other energy and cost efficient streamer applications. These tools can also be used for development of efficient renewable energy storages by recycling carbon dioxide. The research was funded by STW and was performed in the Multiscale Dynamics research group at CWI, under supervision of Ute Ebert. Energy is one of the key research areas of the Amsterdam-based Centrum Wiskunde & Informatica.

More information:
- the homepage of the Multiscale Dynamics research group at CWI
- the PumpKin code en manual: http://www.pumpkin-tool.org

Pictures above: Armen Inants (Inria)

Discharges. Picture: Sander Nijdam, TU/e.