Modeling OH transport phenomena in cold plasma discharges using the level set method

Cold atmospheric plasmas (CAPs) have attracted considerable interest in the field of plasma medicine. Generated reactive species such as hydroxyl (OH) species play an important role in applications of CAPs. Transportation of OH species towards the target and distribution of these OH species in the plasma plume play an important role in the applications of plasma medicine. In the present work, a computational model was built to simulate the transportation and distribution of OH species in CAP discharges, which was based on the level set method to dynamically track the propagation of plasma carrier gas in air. A reaction term was incorporated for the OH species. The OH species tended to diffuse around the main stream of the carrier gas, and thus covered larger radial and axial distances. A CAP discharge onto a skin layer led to the largest accumulation of OH species at the central part of the exposed area. The distribution of OH species on the skin was asymmetric, which agreed with experiments. The computational model itself and the obtained results would be useful for future development of plasma medicine.