Numerical simulation of DC air plasma torch modes and plasma jet instability for thermal spraying technology

Abstract

The article is dedicated to nonstationary simulation of DC air plasma torch. The mathematical model for the analysis of plasma jet instability is developed. The proposed 2D axisymmetric model demonstrates the physical processes taking place inside and in the outer region of the plasma torch. The influence of the power source parameters and anode geometry on voltage and plasma jet fluctuation is described. Simplified mathematical model is developed in order to assess the effect of the flow behavior on heat transfer processes. The developed model can be used for the design of plasma torches and their operation modes. The results of mathematical model verification are based on experimental studies.

Validation of computational fluid dynamics method through experimental investigation of the plasma spraying process

“…It is assumed that the generated plasma jet flows through and out of the torch under the following conditions: it behaves as an ideal gas being in local thermodynamic equilibrium, subjected to turbulent flow, in such a way that it is optically thin, incompressible, and can be considered as a Newtonian continuous fluid at one temperature [4][5][6]. Furthermore, gravitational effect and viscous dissipation are considered negligible, while the transport coefficients and thermodynamic properties of argon-nitrogen plasma are functions of the local temperature [7].…”

“…Based on the aforementioned assumptions, the transport equations, consisting of the continuity (1), momentum (2), energy (3), equation of state (4), and turbulent (5,6) equations are expressed as follows: Here, V ⃗ ⃗ , P, τ ̿, e, λ, T, ∅d, Qj, Qr, ρ, R, k, Гx, G, ε, Гε, Cε1, and Cεr are, respectively, velocity vector, fluid pressure, viscous stress tensor, internal energy, thermal conductivity, fluid temperature, dissipation loss, joule heating, radiation loss, density, gas constant, turbulent kinetic energy, transport coefficient for kinetic energy, generation rate of kinetic energy, dissipation rate of kinetic energy, transport coefficient for dissipation rate, and constant.…”

Mathematical modeling of parameters of solar modules for a solar power plant 2.5 MW in the climatic conditions of the Republic of Cuba

“…The construction of solar power plants in the country is widespread due to a number of advantages: renewability, abundance, constancy and availability of resources, concern for the environment, sound insulation and energy saving. However, solar power plants have two important drawbacks: variable characteristics and dependence on energy production in the face of climate change [1,2].…”