A Numerical Study of Ethanol–Water Droplet Evaporation

Abstract

The present effort focuses on detailed numerical modeling of the evaporation of an ethanol–water droplet. The model intends to capture all relevant details of the process: it includes species and heat transport in the liquid and gas phases, and detailed thermophysical and transport properties, varying with both temperature and composition. Special attention is reserved to the composition range near and below the ethanol/water azeotrope point at ambient pressure. For this case, a significant fraction of the droplet lifetime exhibits evaporation dynamics similar to those of a pure droplet. The results are analyzed, and model simplifications are examined. In particular, the assumptions of constant liquid properties, homogeneous liquid phase composition and no differential volatility may not be valid depending on the initial droplet temperature.

Two‐phase modeling of evaporation characteristics of ethanol droplet under force‐convection environment

“…Numerous research works on the evaporation process of ethanol droplets have been carried out in the past decades. In stagnant ambient conditions, experimental works on hydrous ethanol droplets were carried out by Law et al, 2 Hopkins and Reid, 3 while theoretical studies were performed by Jiang et al, 4 Lupo and Duwig, 5 Pinheiro et al, 6 Millán‐Merino et al 7 using one‐dimensional model by considering spherically symmetric assumption. However, in the most important and demanding practical applications (such as the spray combustion process), droplet evaporation and combustion take place in a highly convective medium under a moderate Reynolds number ( Re » 1) 8 .…”

Evaporation characteristics of ethanol droplet in different gases under force convection condition

“…Moreover, bi-component ethanol and water droplet evaporation process was investigated by Zhang et al [6] and Lupo and Duwig [7]. Also, Millán-Merino et al [8] performed numerical study on evaporation process of mono and multi-component droplet of various types (including pure ethanol).…”

“…A theoretical study on pure ethanol droplet was performed by Pinheiro et al [9] to investigate the combined effects of ambient temperature, pressure and ambient fuel vapor concentration. However, the major drawback of these studies [3][4][5][6][7][8][9] is quiescent atmospheric condition (i.e., zero relative velocity between the droplet and the ambient gas). In practical applications like spray combustion process, evaporation occurs in convective gas medium.…”

A new robust modeling strategy for multi-component droplet heat and mass transfer in general ambient conditions

“…Presented results could well represent the trends observed experimentally for binary mixtures of n-heptane and n-decane. Focusing on binary mixtures of ethanol and water, Lupo and Duwig [12] performed numerical investigations of different initial droplet compositions and effects of preferential diffusion of liquid vapor into the surrounding gas. To address the effects of preferential diffusion, an approach is proposed to address the enthalpy fluxes caused by the different species specific heats into the gas energy equation.…”