Evaluation of non-ideal fluid modeling for droplet evaporation in jet-engine-like conditions

Abstract

Mid-century climate neutrality targets for the aviation industry foster the development of ultra-high overall pressure ratio jet engines. Consequently, comprehensive numerical models driving the design process must tackle the severe thermodynamic conditions expected to occur during the various flight operational phases. In the current study, we present a cost-effective framework for addressing droplet vaporization phenomena in jet-engine-relevant conditions, leveraging real-fluid thermophysical modeling and high-pressure vapor-liquid equilibrium interfacial thermodynamics. We evaluate the impact of a non-ideal fluid approach on predicting the evaporation process of a single n-dodecane droplet in air, mimicking operating conditions relevant to aero-engines. For the conditions examined, the numerical results indicate that adopting a real-fluid thermodynamic treatment results in a deviation of the droplet vaporization rate from an ideal-fluid approach, for which we have outlined the thermodynamic states that lead to mixture non-ideality. Notably, we envisage the most impactful model discrepancies in transport property estimation, thus affecting the heat and mass transfer rates. Lastly, we analyze and quantify the role of the detailed phase equilibrium model in the droplet evaporation process, assessing its actual impact for the conditions of interest, and discussing the cost-effectiveness in commonly computational fluid dynamics tools.