Generation of Long Laminar Plasma Jets: Experimental and Numerical Analyses

Numerical modelling of a direct current non‐transferred thermal plasma torch for optimal performance

“…This suggests that the plasma jet length extends beyond the simulated domain which measures 379 mm from the torch exit. Previously, Sen et al [ 11 ] have experimentally demonstrated laminar plasma jets of lengths ranging from 100 to 720 mm for different power inputs. Also, the average Reynolds numbers $$$ \operatorname{Re} $$$ of the jet at torch exit are $$$ \operatorname{Re} $$$ = 22.8 and 24.2 for Cases I and II respectively, confirming that the jet is laminar and higher jet lengths should be expected.…”

“…In the MHD approach, fluid equations are coupled with Maxwell's equations, and the effects of plasma's electromagnetic properties are thereby incorporated. Accordingly, the following assumptions have been made for the numerical model: The plasma flow inside and outside the torch is assumed to be in steady‐state, laminar, [ 11,33 ] and axially symmetric, thus described using cylindrical coordinates. Plasma is in LTE, that is, $$$ {T}_e\backsim {T}_i $$$, where $$$ {T}_e $$$ and $$$ {T}_i $$$ are electron and ion temperatures (K), respectively. The effect of forces due to gravity and viscous dissipation as well as the compressibility effects are neglected. The plasma is assumed to be optically thin, that is, the plasma does not absorb radiation energy. Variations in thermodynamic and transport properties of argon and other plasma gases as a function of temperature have been obtained from the work of Boulos et al [ 2,34–36 ] The ambient environment is assumed to be comprised of the same gas as the carrier or plasma gas, thus negating any additional effects due to mixing or entrainment. …”

“…On the other hand, laminar plasma jets have lower ambient gas entrainment, higher temperature, and higher velocities for a longer axial length. [ 11 ] These properties of laminar plasma jets have drawn the interest of many researchers in the past. For example, Zhukov's research group in the Russian Academy of Sciences had developed a DC non‐transferred laminar plasma torch with applications in chemical technologies.…”

Atmospheric pressure plasma treatments protect neural cells from ischemic stroke‐relevant injuries by targeting mitochondria

“…[ 7,8 ] On the basis of a large number of reactive agents generated by plasma jets in the open environment, such as ultraviolet, charged particles, reactive nitrogen species (RNS) and reactive oxygen species (ROS), [ 9 ] the development of APPJ in biomedicine has become one of the most successful applications, [ 10 ] including sterilization, [ 11 ] wound healing, [ 12 ] root canal treatment, [ 13 ] and cancer treatment. [ 14 ] Although most previous studies have focused on plasma‐induced oxidative and nitrative stress on the treatment objects, our previous studies showed the neuroprotective effect of low‐dose APPJ against different kinds of injuries in vitro, such as oxidative stress, [ 15 ] glucose deprivation, [ 16 ] and hypoxia [ 17 ] ; however, the intracellular targets of APPJ and the mechanisms of the interactions between the APPJ and cells are still unknown.…”

Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings

“…Figure 2: a) Current/voltage characteristics of main DC plasma torches families used in plasma spraying of liquid feedstocks, Conventional Torch (CT), Segmented Torch (ST), Multielectrode Torch (MT), Axial Multi-electrode Torch (AMT). b) Specific enthalpy dependence on electrical power(20,(22)(23)(24).…”