Droplet vaporization under high-pressure stagnant conditions has been studied numerically. Computations have been performed using both a high pressure (HP) and a low pressure (LP) model. Results are presented for an n-hexane droplet evaporating into a nitrogen environment, for initial temperature of 300 K, ambient pressures of 1-80 atm and ambient temperatures of 500-1000 K. It is predicted that at supercritical pressures the droplet surface temperature, Ts, keeps rising until the end of the droplet lifetime. Compared to the HP model, the LP model overpredicts the droplet lifetime, the deviation increasing with pressure. At high ambient temperatures (1000 K), the LP model predicts droplet lifetimes with sufficient accuracy even up to ambient pressures as high as 50 atm, however, it is inadequate for other cases such as high ambient pressures and relatively low ambient temperatures. The range of applicability of the LP model, which is much simpler to use, is clearly delineated. The gas-phase quasi-steady assumption fails with increasing ambient pressure and underpredicts the droplet lifetime substantially.
ASJC Scopus subject areas
- Aerospace Engineering