Modelling of heating and evaporation of automotive fuel droplets: recent results and unsolved problems

S.S. Sazhin, Mansour Al Qubeissi, M.R. Heikal

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Abstract

This paper presents an overview of recent progress in the modelling of biodiesel, Diesel and gasoline fuel droplet heating and evaporation under typical internal combustion engine conditions. A Discrete Component Model is used for modelling of heating and evaporation of multi-component biodiesel fuel droplets used in direct injection internal combustion engines. This model takes into account the effects of temperature gradient, recirculation and species diffusion inside droplets. A distinctive feature of the model, used in the analysis, is that it is based on the analytical solutions to the heat transfer, evaporation and species diffusion equations inside the droplets. Modelling of the heating and evaporation of Diesel and gasoline fuel droplets is based on the multi-dimensional quasi-discrete model, which is shown to achieve a good compromise between accuracy and CPU efficiency of calculations. When this model is applied to a typical Diesel fuel, this fuel is simplified to form six groups: alkanes, cycloalkanes, bicycloalkanes, alkylbenzenes, indanes & tetralines, naphthalenes, and three characteristic components C19H34 (tricycloalkane), C13H12 (diaromatic), and C14H10 (phenanthrene). Each of the six groups is presented as a sum of quasi-components as in the case of the earlier developed quasi-discrete model. Each quasi-component and component is treated as a component in the Discrete Component Model. It is shown that errors in estimated temperatures and evaporation times of droplets, under typical Diesel engine conditions, using the approximation of Diesel fuel by 15 quasi-components/components compared to the ones predicted by the model taking into account the original composition of 98 components, are up to 2% and 3% respectively, which is acceptable in most engineering applications. This approximation has also reduced CPU time to a sixth of that for the case when the contribution of 98 components was taken into account. Also, the approximations of Diesel fuel with n-dodecane (widely used in engineering modelling) and 20 alkane components is shown to lead to under-prediction of the evaporation time by about 50% and 22% respectively, which is unacceptable in most engineering applications. The most important unsolved problems are identified.
Original languageEnglish
Pages181-186
Publication statusPublished - 2015
Event7th Baltic Heat Transfer Conference - Tallinn, Estonia
Duration: 24 Aug 201526 Aug 2015

Conference

Conference7th Baltic Heat Transfer Conference
Abbreviated titleBHTC’2015
CountryEstonia
CityTallinn
Period24/08/1526/08/15

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Bibliographical note

Copyright: Tallinn University of Technology.

Keywords

  • automotive fuel droplets
  • heating and evaporation

Cite this

Sazhin, S. S., Al Qubeissi, M., & Heikal, M. R. (2015). Modelling of heating and evaporation of automotive fuel droplets: recent results and unsolved problems. 181-186. Paper presented at 7th Baltic Heat Transfer Conference, Tallinn, Estonia.