EFFECTS OF MULTIPLE DROPLET INTERACTION ON DROPLET VAPORIZATION IN SUBCRITICAL AND SUPERCRITICAL PRESSURE ENVIRONMENTS

Dilute- and dense-cluster droplet vaporization is studied numerically over a 1-60-bar pressure range. The present model applies the ''sphere of influence'' concept to account for multiple droplet interaction. H igh-pressure effects are dealt with by solving both gas- and liquid-ph ase transient flows, as well as by including the effects of ambient ga s solubility, property variation, thermodynamic nonideality, and trans ient diffusion. N-pentane dilute spray results reveal that variations in predicted droplet lifetime are qualitatively in agreement with prev ious single droplet vaporization studies. With dense spray n-pentane, droplet lifetime is significantly prolonged at low initial ambient pre ssures, monotonically decreasing as initial ambient pressures rise. It is predicted that saturation occurs only for a dense enough cluster o f droplets. Dilute sprays at initially high ambient temperatures and p ressures can reach the critical mixing state, unlike dense sprays in w hich the ambient temperature and pressure are substantially reduced du e to cooling by droplet vaporization.