Atomization of Bio-Fossil Fuel Blends

Abstract

The importance of modeling multi-component fuel atomization, heating and evaporation has been recognized in many studies. The predictions of these models are crucial to the design and performance of combustion engines. Accurate modeling is essential to the understanding of these processes and ultimately to improving engine sustainability and reducing emission. The interest in bio-fossil fuel blends has been mainly stimulated by depletion of fossil fuels and the need to reduce carbon dioxide emissions that contribute towards climate change. This work presents a review of recent investigations into the heating and evaporation of multi-component blended fuel droplets in real internal combustion engine (ICE) conditions. The models consider the contribution of all groups of hydrocarbons in fossil (gasoline, diesel) fuels, methyl esters in 22 biodiesel fuels, and ethanol fuel. Diffusion of these fuel species, temperature gradient, and recirculation within droplets are accounted for. One important finding is that some fuel blends, for example B5 (5% biodiesel fuel and 95% diesel fuel) and E5 (5% ethanol fuel and 95% gasoline fuel), can give almost identical droplet lifetimes to the ones predicted for pure diesel and gasoline fuels; i.e. such mixtures can be directly used in conventional engines without modification.

The impacts of the activity coefficient on heating and evaporation of ethanol/gasoline fuel blends

“…The DC model was used previously for the analysis of blended fuel droplet heating and evaporation, including blends of diesel/biodiesel and ethanol/gasoline fuels [17,[20][21][22][23][24]. In these studies, however, Raoult's law was assumed to be valid (the activity coefficient (AC) was assumed equal to one).…”

Introductory Chapter: Biofuels - Challenges and Opportunities

“…To conclude, the use of biofuels is expected to contribute to the energy sustainability and reduction of global warming. For instance, many efforts have been made to replace gasoline and diesel fuels with ethanol/gasoline and biodiesel/diesel fuel blends, respectively [11][12][13][14][15][16]. These efforts have been driven mainly by the importance of reducing greenhouse emissions and fossil fuel costs [17][18][19].…”

Blended E85–Diesel Fuel Droplet Heating and Evaporation

“…32,33 The DC and MDQD models have been applied to gasoline, diesel, biodiesel and their blends. [25][26][27][33][34][35][36][37][38] This paper is focused on the analysis of blended E85-diesel fuel droplets. In contrast to most previous studies, where Raoult's law was assumed to be valid (i.e.…”

“…As with the DC model, the MDQD model is based on the effective thermal conductivity/effective diffusivity (ETC/ED) models to solve the heat transfer and species diffusion equations. The latter models allow one to take into account the recirculation inside the droplets, due to their relative movement, and its effect on the droplet average surface temperature and species mass fractions within a one-dimensional model. , The DC and MDQD models have been applied to gasoline, diesel, biodiesel, and their blends. − ,− This paper is focused on the analysis of blended E85–diesel fuel droplets. In contrast to most previous studies, where Raoult’s law was assumed to be valid (i.e., the activity coefficient (AC) was assumed to be unity), the authors of ref took into account the contributions of nonunity AC, using the universal quasi-chemical functional group activity (UNIFAC) model.…”