Hai-Xing Wang

Thermodynamic and transport properties of two-temperature lithium plasmas

Thermodynamic and transport properties of two-temperature lithium plasmas are calculated for the pressure range from 0.0001 to 1 atm, electron temperatures from 1000 to 40 000 K and the electron/heavy particle ratio from 1 to 5. The calculated results are presented concerning the variation with the electron temperature of the plasma composition, specific enthalpy, specific heat, viscosity, electrical conductivity, thermal conductivity and diffusion coefficient with the gas pressure and electron/heavy-particle temperature ratio as the parameters. The effects of gas pressure and electron/heavy-particle temperature ratio on lithium plasma properties are discussed in terms of the variation of gas ionization degree with gas pressure and temperature. For the special case with gas temperature below 10 000 K and without accounting for gas ionization, the present calculated results about lithium viscosity and thermal conductivity at atmospheric pressure are consistent with those reported in the literature.

Numerical investigation of the plasma flow through the constrictor of arc-heated thrusters

A modelling study is performed to investigate the plasma flow through the constrictor of medium-power arc-heated thrusters. The Roe scheme is employed to solve the governing equations, which take into account the effects of compressibility, Joule heating and the Lorentz force, as well as the temperature and pressure dependence of the gas properties. The modelling results show that the gas flow within the constrictor is choked by the combined effects of friction and arc heating. The computed total pressure drop within the constrictor due to friction and arc heating is about twice the dynamic head at the constrictor outlet. The effects of the arc current, inlet pressure and mass flow rate, and the constrictor length and diameter on the gas flow characteristics within the constrictor are presented and discussed. Further, it is shown that the choking effects caused by arc heating reduce the flow rate more strongly for argon and nitrogen working gases than for hydrogen working gas.

Numerical modelling of the nonequilibrium expansion process of argon plasma flow through a nozzle

A two-temperature thermal and chemical nonequilibrium model is developed and applied to investigate the expansion processes of an argon plasma flow through a Laval nozzle. This model describes in a self-consistent manner the gas flow and heat transfer, the coupling of the electric energy deposited into the plasma, and the reaction kinetics including the contribution of excited species. It is found that the plasma is far from thermodynamic equilibrium in the entire argon plasma flow expansion process through a nozzle. Significant temperature discrepancies between electrons and heavy species are found in the cooler outer region. The dominant chemical kinetic processes in different plasma gas expansion regions are presented and discussed. It is noted that although the number density of excited argon atoms (Ar*) is much lower than that of other species in the argon plasma, Ar* play important roles in the ionization and recombination processes, and in arc attachment to the anode.

Two-Temperature Chemical-Nonequilibrium Modelling of a High-Velocity Argon Plasma Flow in a Low-Power Arcjet Thruster

A numerical simulation has been performed of a high-velocity argon plasma arc flow in a low power arcjet including a finite-rate chemical kinetic model. Electrons, ions, molecular ions (

Numerical Simulation of Nonequilibrium Species Diffusion in a Low-Power Nitrogen-Hydrogen Arcjet Thruster

{\text{Ar}}_{2}^{ + }

Images of Arc-Heated Supersonic Argon Plasma Jet Impinging on a Flat Plate

Ar2+), neutral atoms including the ground and excited argon atoms (Ar*) are treated as separate species in the plasma mixture. The chemical reactions considered are excitation, de-excitation, ionization and recombination processes, in which reactions involving excited argon atoms (Ar*) and molecular ions (

Numerical Modeling of Heat Transfer and Flow in Low Power Arcjet Thruster

{\text{Ar}}_{2}^{ + }