08/19/2022
By Sokny Long

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a doctoral proposal defense by Valentin Boutrouche on "Modeling and Characterization of a Self-sustained Atmospheric Pressure Glow Discharge."

Ph.D. Candidate: Valentin Boutrouche
Defense Date: Monday, August 22, 2022
Time: 10 to 11:30 a.m.
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Valentin_Boutrouche@student.uml.edu or committee chair Juan_Trelles@uml.edu at least 24 hours prior to the defense to request access to the meeting

Committee Chair (Advisor): Juan Pablo Trelles, Associate Professor, Department of Mechanical Engineering, UMass Lowell

Committee Members:

  • Maria Carreon, Assistant Professor, Department of Mechanical Engineering, UMass Lowell
  • Ofer Cohen, Assistant Professor, Department of Physics, UMass Lowell
  • Noah Van Dam, Assistant Professor, Department of Mechanical Engineering, UMass Lowell

Brief Abstract:
The electrification of manufacturing process, powered through renewable energy, is regarded as a major way to mitigate greenhouse gas emissions driving global warming. In this setting, low-temperature atmospheric pressure plasma sources provide highly reactive environments while operating at relatively mild conditions, making them appealing to an increasingly wider range of applications in materials processing, chemical synthesis, water treatment, and medicine. Among the different types of plasma sources considered for low-temperature atmospheric pressure processing, the Atmospheric Pressure Glow Discharge (APGD) is a relatively simple and versatile plasma source whose efficacy has been demonstrated in a wide range of applications. Stable APGD operation at high currents is generally challenging due to instabilities leading to glow-to-arc transition. However, it has been recently demonstrated that this transition can be avoided by controlled cathode cooling. This doctoral dissertation research consists in the computational modeling and characterization of a self-sustained APGD in thermal and chemical non-equilibrium. This work is based on previously published experimental results of a pin-to-plate APGD within a 10 mm interelectrode gap. The computational model is implemented in our in-house Partial Differential Equation solver, TPORT, which is based on a nonlinear variational multi-scale finite element method. The validation of the model and characterization of the discharge was carried over a range of current from 4 to 40 mA and the results were compared against experimental findings. Modelling results show good agreement with the experimentally measured voltage drop and the same trend but higher values of positive column temperature. The results reveal that over the range of current considered, the discharge presents two regimes: as the current increase the distribution of electron transitions from monotonically increasing away from the cathode to presenting a minimum near the center of the interelectrode gap. The proposed work consists of an investigation of the different regime of the discharge and the possible self-organization of the discharge leading to patter formation over the cathode surface.