Comparative analysis of lumped parameter and one-dimensional continuum models for droplet evaporation at elevated pressures and temperatures

Droplet evaporation plays a critical role in a wide range of industrial and technological applications, from combustion engines to spray coating and refrigeration. While Eulerian-Lagrangian models are widely used for predicting droplet behavior, they often assume a uniform internal temperature, which may not be valid under high-temperature and high-pressure conditions. This study compares the traditional lumped parameter model ( LPM ) with a novel one-dimensional model employing a staggered grid ( 1D-SG ) approach. Both models are applied to water droplets in air over a broad range of initial diameters, relative velocities, and ambient pressures and temperatures. The analysis evaluates deviations in droplet lifetime and evaporation rate between the two approaches, emphasizing the influence of Biot number, which is more sensitive to pressure than to temperature. Results show that LPM remains accurate for small droplets and low convection conditions, with deviations under 1 %. However, for larger droplets and enhanced convection, discrepancies in evaporation rate and lifetime reach up to 6 % and 8 %, respectively. The findings demonstrate that while LPM is computationally efficient, its applicability depends on droplet size and flow conditions. The proposed 1D-SG model offers a more physically consistent alternative when higher accuracy is required, providing guidance for model selection in spray-related simulations. • A novel 1D staggered grid approach is proposed for droplet evaporation. • Lumped and 1D models are compared across wide droplet and flow conditions. • Biot number shows higher sensitivity to pressure than to temperature. • Lumped model is accurate for small droplets without enhanced convection. • Deviation values and model selection guidance are provided for spray simulations.