Numerical solutions of compressible two-phase moist-air flow with shocks

Numerical solutions of a compressible two-phase two-component moist-air flow with and without shock waves are investigated in this paper using the high resolution flux difference splitting scheme of Roe (1981) [22]. The solver is spatially third order and temporally second order accurate. The flow is assumed to obey an equilibrium thermodynamic model. For the two-phase flow in dry regions, the pressure (P)(P), temperature (T)(T), and velocity (u)(u) are extrapolated to the cell faces by the MUSCL approach, while in wet regions the steam quality (χ)(χ) has been used instead of pressure. Comparisons of the wetness fraction at the nozzle exit show that in the case of moist-air flow rather than pure steam, a much higher wetness fraction, about 30%, can be achieved, while in the case of pure steam and under similar conditions the wetness fraction is limited to about 6%. The present study gives a practical guideline in the production of liquid water in a much higher rate, if an additive gas (like air) is added to steam. Hence it can be used as an alternative approach to produce potable water from atmospheric air in geographically humid regions. For moist-air flow with normal shock, the results show that across the shock the liquid phase rapidly evaporates.