Numerical analysis of moist-air flow in converging-diverging nozzlewith equilibrium and non-equilibrium thermodynamic models

In this paper, the numerical solution of compressible, transonic, unsteady, inviscid and two-phase of moist-air flow in converging-diverging nozzles is studied. To do so, both equilibrium and non-equilibrium thermodynamic models with Roe's scheme are considered and the results are compared. In equilibrium thermodynamic model, the solver is spatially third order and temporally second order accurate, but in non-equilibrium thermodynamic model, the solver is spatially first order and temporally second order accurate. For the moist air in dry region the pressure, temperature, and velocity are extrapolated while in wet regions the steam quality has been used instead of pressure. In this study, the influence of the geometry expansion rate and inlet total temperature and pressure on nucleation rate and the wetness fraction at the nozzle exit are investigated. The results show that by increasing the expansion rate of nozzle the condensation onset occurs earlier; also, the nucleation rate and wetness fraction at the nozzle exit is increased. Comparing the results of equilibrium and non-equilibrium thermodynamic models show that the non-equilibrium thermodynamic model has better agreement with the experimental data.