Subcritical and Supercritical Droplet Evaporation within a Zero Gravity Environment; On the Discrepancies between Theoretical and Experimental Results

Abstract

A comprehensive axisymmetric numerical model has been developed to study high pressure droplet evaporation. In this model, high pressure transient effects, variable thermo-physical properties and inert species solubility in the liquid-phase are considered. First, the axisymmetric model has been utilized to explain the discrepancy between theoretical and experimental results on microgravity droplet evaporation that has been reported in the literature [J.R. Yang and S.C. Wong, Ref. 35]. In addition, this effort led to a thorough validation of the model against the most extensive microgravity experimental data available in the literature on droplet evaporation. Second, the validated model has been utilized to investigate spherically symmetric droplet evaporation for a wide range of ambient pressures and temperatures. The predictions show that the average droplet evaporation constant decreases with ambient pressure at sub-critical ambient temperatures, becomes insensitive to pressure at ambient temperatures around the critical temperature of the fuel and presents a local maximum while increasing with the ambient pressure at super-critical ambient temperatures.

Archives of Thermodynamics

“…However, real gas effects and density variations were ignored in that model. Since then several investigators considered the real gas effects in their models, using cubic equations of state such as Redlich-Kwong (RK), Soave (SRK) and Peng-Robinson (PR) equations of state [3][4][5][6][7][8][9][10][11][12][13][14]. In general, properties were estimated neglecting the effect of pressure in those models.…”

“…In general, properties were estimated neglecting the effect of pressure in those models. Predominantly, these numerical models considered binary systems [4][5][6][7][8][9][10][11][12][13][14]. In multicomponent droplet evaporation study, the solubility of ambient gas such as nitrogen in the multicomponent liquid phase was neglected [15].…”