抄録
A rapid expansion of moist air or steam in a supersonic nozzle gives rise to non-equilibrium condensation. If the latent heat released by condensation exceeds a certain quantity, the flow becomes unstable and a periodic flow oscillation occurs. In the present study, a numerical simulation of moist air flows in a supersonic nozzle was carried out using a special short duration supersonic wind tunnel, called a Ludwieg tube. The effects of the height of nozzle throat and initial relative humidity of the moist air have been shown for static pressure, condensate mass fraction and nucleation rate and total pressure loss numerically. As a result, it was found that the characteristics of flow with occurrence of condensation upstream of nozzle were largely different from that with occurrence of condensation in the nozzle.
