A fuel injection system in a diesel engine has different processes that affect the complete burning of the fuel in the combustion chamber. These include the primary and secondary breakups of liquid fuel droplets and evaporation. In the present paper, evaporation of two different diesel fuels has been modelled numerically. Evaporation of n-heptane and n-decane is governed by the conservation equations of mass, energy, momentum, and species transport. Results have been plotted by varying the droplet diameter and temperature. It was observed that droplet size, temperature of droplets, and ambient temperature have notable effect on the evaporation time of diesel fuel droplets in the engine cylinder.

Renewable energy resources are need of the hour at the current energy scarcity scenario in the world. Scientist and researchers are finding the ways to replace the conventional energy resources with the renewable ones. It is fact that fossils are going to be obsolete in future. One third of global energy is being consumed by the transportation sector. All the amount of this energy comes from the fossils that contain the hydrocarbons in their composition. Efforts are being made to replace the fossils with the renewable energy resources. In this regard, biofuels are emerged as a replacement of the diesel fuels. There are several processes in the engine cylinder from atomization of fuel until the exhaust of gases. One of them is the evaporation of fuel droplets. In the present work, evaporation characteristics of conventional diesel fuel and biofuels is described by comparing them in different working conditions. Modeling of evaporation phenomenon using computational fluid dynamics (CFD) techniques and the effects of in cylinder conditions is also explained. Results show that biofuel droplets show a better evaporation rate at the high operating conditions in the engine cylinder.