Abstract
We experimentally studied a cavitating flow in a two-dimensional convergent-divergent nozzle with a diverging angle of 8.4° using HFE (hydro-fluoro-ether), by which we can expect to observe thermal effect at room temperature. But the amount of dissolved air in HFE is very large, so we have to take account of the effect of air inclusion inside cavitation bubbles. Then we redefined the modified cavitation number to remove the effect of dissolved gas assuming that pressure at nozzle throat equals to cavity pressure. Except the lowest throat velocity case, the more cavity length was gradually increased, the faster velocity at throat was, compared to same modified cavitation number, revealing the thermodynamic effect of cavitation. In the lowest velocity case, the cavity length seemed to tend to be overestimated due to many tiny air bubbles downstream of sheet cavities formed from separations of dissolved air.
