Modelling of heating and evaporation of gasoline fuel droplets: A comparative analysis of approximations

Abstract

Modelling of gasoline fuel droplet heating and evaporation processes is investigated using several approximations of this fuel. These are quasi-components used in the quasi-discrete model and the approximations of these quasi-components (Surrogate I (molar fractions: 83.0% n-C 6 H 14 + 15.6% n-C 10 H 22 + 1.4% n-C 14 H 30 ) and Surrogate II (molar fractions: 83.0% n-C 7 H 16 + 15.6% n-C 11 H 24 + 1.4% n-C 15 H 32 )). Also, we have used Surrogate A (molar fractions: 56% n-C 7 H 16 + 28% iso-C 8 H 18 + 17% C 7 H 8 ) and Surrogate B (molar fractions: 63% n-C 7 H 16 + 20% iso-C 8 H 18 + 17% C 7 H 8 ), originally introduced based on the closeness of the ignition delay of surrogates to that of gasoline fuel. The predictions of droplet radii and temperatures based on three quasi-components and their approximations (Surrogates I and II) are shown to be much more accurate than the predictions using Surrogates A and B.

Modelling of biodiesel fuel droplet heating and evaporation

“…As follows from this figure, the multi-component model predicts higher droplet surface temperatures and longer evaporation times compared with the single component model. This result is consistent with the one earlier reported in [15,16,17] for Diesel and gasoline fuel droplets. As in the case of the abovementioned fuels, this behaviour of the droplet surface temperature and radius can be related to the fact that at the final stages of droplet evaporation the mass fraction of species with larger numbers of carbon atoms n (C20:1 M, C18:1 M, C18:2 M, C18:0 M) increases at the expense of species with smaller n (C16:0 M) except at the very final stage of droplet evaporation.…”

“…For modelling multi-component droplet heating and evaporation, with many species involved, a new model, called the quasi-discrete model was suggested and developed in [15,16,17]. This model is based on the introduction of quasi-components, describing groups of actual components with close properties.…”

A multi-dimensional quasi-discrete model for the analysis of Diesel fuel droplet heating and evaporation

“…Firstly, even if we restrict our analysis only to alkanes, it does not appear to be easy to approximate this distribution with a reasonably simple distribution function f m (n), given by Expression (1) (similar to the one used in [7,8,9]). Secondly, the contributions of the other five hydrocarbon groups apart from alkanes, presented in Table 2, cannot be ignored in any realistic model of Diesel fuels.…”

“…As demonstrated in our recent publications [7,8,9], the most important of the above-mentioned assumptions is that Diesel fuel can be approximated by a single component. The early models, taking into account the effect of multiple components in Diesel engines, could be subdivided into two main families: those based on the analysis of individual components (Discrete Component Models (DCM))(e.g.…”

“…Although the usefulness and efficiency of the quasi-discrete model was clearly demonstrated in [7,8,9], this model still has a number of serious limitations the most important of which is that it is based on the assumption that Diesel and gasoline fuels consist only of n-alkanes. At the same time, as will be shown later in this paper, the total molar fraction of alkanes (nalkanes and iso-alkanes) is only about 40% of the overall composition of Diesel fuels (a similar conclusion could be drawn for gasoline fuel [18]).…”