Liquid dynamics in response to an impinging low-temperature plasma jet

Abstract

The liquid-phase behavior induced by an atmospheric pressure plasma jet impinging onto water-based solutions was experimentally investigated. An increase in cavity size and circulation size resulting from an increase in impact force of the plasma jet with respect to a helium gas jet were observed through particle image velocimetry and cavity measurements. The increase in circulation size due to plasma discharge was larger than the increase solely due to an increase in jet impact force, suggesting additional shear along the liquid free surface evidenced by schlieren images of plasma-induced gas flow adherence after impingement. Liquid evaporation rate increased and mean liquid temperature decreased due to plasma effects on jet behavior. Plasma-induced decreases in liquid pH and temperature were contained within the circulation flow, leading to strong pH and temperature gradients within the liquid volume. Areas treated by the jet became acidic and remained more acidic than other portions of the liquid due to circulation vortices, highlighting the consequences of jet and liquid vessel parameters for plasma jet-liquid applications.

Antibacterial effects of low-temperature plasma generated by atmospheric-pressure plasma jet are mediated by reactive oxygen species

“…While the design and technical details of the jet are discussed in materials and methods section, Fig. 1 (left panel) depicts a schematic of the APPJ system 20 . Figure 1 (right) shows the jet during operation exposed to living tissue, demonstrating the non-thermal nature of the device.…”

A review of the gas and liquid phase interactions in low-temperature plasma jets used for biomedical applications

“…The induced flow in the liquid phase by the APPJ depends on the velocity of the effluent, which is determined by the capillary-to-target distance, jet orifice diameter and the gas flow rate [113]. A helium APPJ impinging on waterbased solution was studied using Schlieren imaging and PIV [126], where it was shown that an increase in the normal and shear forces exerted by the jet on a liquid target causes an increase in the liquid flow velocity and circulation size. The presence of fluid motion alters the generation and transport of species, by the generation of vortexes directly affecting the transmission of species from the interface to the liquid bulk [83,113] Brubaker et al observed that the interaction between the jet and the liquid can provoke a non-homogeneous decrease in temperature and a reduction of pH [126].…”

Functional nitrogen science based on plasma processing: quantum devices, photocatalysts and activation of plant defense and immune systems

“…245,246) Brubaker et al measured temporal changes in RONS concentrations throughout the depth of a liquid vessel and established that the plasma-induced liquid flow played an important role in determining reactive species concentrations at various locations in the liquid. 247,248) The flow of gases associated with the plasma irradiation forms a cavity on the liquid surface, and the depth of this cavity is determined by the balance between the electrohydrodynamic (EHD) force and the buoyancy of the liquid. 249) Studies have indicated that the plasma EHD force changes the mass transport inside the liquid, [248][249][250] such that unusual phenomena can appear in plasma-irradiated liquids.…”

“…247,248) The flow of gases associated with the plasma irradiation forms a cavity on the liquid surface, and the depth of this cavity is determined by the balance between the electrohydrodynamic (EHD) force and the buoyancy of the liquid. 249) Studies have indicated that the plasma EHD force changes the mass transport inside the liquid, [248][249][250] such that unusual phenomena can appear in plasma-irradiated liquids. 7.1.4.…”