Thermodynamic and Transport Properties of Real Air Plasma in Wide Range of Temperature and Pressure

Abstract

Air plasma has been widely applied in industrial manufacture. In this paper, both dry and humid air plasmas' thermodynamic and transport properties are calculated in temperature 300-100000 K and pressure 0.1-100 atm. To build a more precise model of real air plasma, over 70 species are considered for composition. Two different methods, the Gibbs free energy minimization method and the mass action law method, are used to determinate the composition of the air plasma in a different temperature range. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto has been applied using the most recent collision integrals. It is found that the presence of CO2 has almost no effect on the properties of air plasma. The influence of H2O can be ignored except in low pressure air plasma, in which the saturated vapor pressure is relatively high. The results will serve as credible inputs for computational simulation of air plasma.

Stochiometry Air − CH4 Mixture: Composition, Thermodynamic Propertiess and Transport Coefficients

“…Based on this plasma composition, the thermodynamic properties can be calculated. As an example of validation we compare in Figure 2 the specific heat at constant pressure with the works of Wang et al [17] and Boulos et al [18]. A good agreement is also found.…”

“…The conventional formulations of the literature based on the third approximation order of Chapman-Enskog Figure 2. Specific heat of air at 1 bar compared with Wan et al [17] and Boulos et al [18]. method are used for the determination of transport coefficients [19,20].…”

Curved Trajectory Effect on Charge‐Exchange Collision at Ionospheric Temperatures

“…As mentioned in Section 1, some previous studies have estimated the total MTCS as the root‐sum‐square of the polarization and classic‐type charge‐exchange components (e.g., Bruno et al., 2010; Capitelli et al., 2013; Laricchiuta et al., 2009; Levin & Wright, 2004; Murphy, 1995, 2000, 2012; Wang et al., 2016; Wright et al., 2007); that is, $$${S}_{\text{MT}}^{\text{total}}\equiv \sqrt{{({S}_{\text{pol}})}^{2}+{({S}_{\text{MT}}^{\text{str}})}^{2}},$$$ as shown by the line labeled Murphy1995 in Figure 6. The corresponding maximum enhancement is 41% by definition, that is, $$\sqrt{2}-1$$.…”

Thermophysical Properties of Electric Arc Plasma and the Wire Melting Effect with Lanthanum and Sulfur Fluorides Addition in Wire Arc Additive Manufacturing

“…Improvement of arc stability and wire melting is associated with thermophysical characteristics of plasma, plasma ionization, and balance of forces acting during wire melting and formation of a weld pool. Improvement of arc properties can be achieved through modeling an electric arc and controlling thermophysical properties of plasma through the addition of molecular compounds [34,35]. Weglowski [34] determined the presence of ionized iron and manganese vapors in the arc spectrum and suggested using the intensity of the arc radiation for neural network control.…”

“…Weglowski [34] determined the presence of ionized iron and manganese vapors in the arc spectrum and suggested using the intensity of the arc radiation for neural network control. Wang et al [35] calculated the thermophysical properties of plasma at the temperature of 300-100,000 K. Introduction of H 2 O into the plasma increases the specific heat, thermal, and electrical conductivity and decreases the viscosity. To improve the melting of the metal and the formation of the weld pool, it is necessary to study the balance of the forces acting on the plasma flow and the droplet transfer.…”