EVAPORATION OF BINARY ETHANOL-BUTANOL MIXTURE DROPLETS

Анотація

This paper presents the results of theoretical and experimental studies of individual droplets evaporation of ethanol(E), butanol(B) and their mixture at 60% ethanol on mass (60%E+40%B) in the heated air environment in the temperature range of 350÷700K and atmospheric pressure. The appearance of effective technologies for the synthesis of renewable fuels from biomass opens the new possibilities for the use of these alcohols as alternative fuels. In practice, alternative fuels are used as components for mixture with fossil fuels. One of the main problems of attempting to increase part of biofuel additions into mixture with transport fuels lies in difference of biofuels thermophysical properties and ones for fossil fuels. These features substantially influence on processes of drop formation  and evaporation, ignition and combustion of the modified air – fuel mixture in a combustion chamber. The fuel drops evaporation as the initial stage of combustion in the engine chamber determines efficiency of all other processes. Therefore, the studies of biofuel drop evaporation and ones for their mixtures are relevant.

Theoretical modelling of drops vaporization process of these liquid biofuels mixture has been conducted by the using discreet-component approach with the system of thermo- and masstransfer equations for each component of the mixture. So, this system is including (i+1) equations. For evaporation kinetics experimental study the suspended drop’s method was used. There are the received dependences of the droplet current diameter and temperature on time which demonstrate the availability of the staging of the mixture evaporation. On the first stage ethanol as the liquid with lower boiling temperature evaporates more intensively. After that there is only butanol at the droplet as the liquid with higher boiling temperature. The second stage is the stationary vaporization of the leftover component of the mixture. The analysis of dependence  allowed to estimate  duration of droplets evaporation both for single-component biofuels and for their mixture. The experimental values of evaporation duration correlates with calculations data.