In this research, the results of comparative analysis of a single fuel droplet evaporation models are presented. Three well-known evaporation models including Spalding, Borman-Johnson and Abramzon-Sirignano models are analyzed using Computational Fluid Dynamic (CFD). The original Spalding model is extended to consider the effects of the Stefan flow, unsteady vaporization, and variable propertie...

The analysis of conformational changes of hydrocarbon molecules is imperative in the prediction of their transport properties in different phases, such as evaporation/condensation coefficients (β) in the gas-liquid interface and evaporation rates of fuel droplets (k) in multiphases. In this letter, we analyze the effects of entropic contributions (T∆Sev(T)) to ∆Gev(T) during the evaporation/con...

in this paper, a non-isothermal two-phase flow in the cathode gas diffusion layer (gdl) of pem fuel cell is modeled. the governing equations including energy, mass and momentum conservation equations are solved by numerical methods. also, the optimal values of the effective parameters such as the electrodes porosity, gas diffusion layer (gdl) thickness and inlet relative humidity are calculated...

Numerical simulations of combustion in aircraft engines is quite complex, as it requires an adequate description of liquid fuel injection, liquid fuel atomization, drop breakup, drop dynamics, and evaporation, large-scale turbulent fuel air mixing, small scale molecular fuel air mixing, chemical reactions, and turbulence/chemistry interactions. In the present paper, we have identified three of ...

Two approaches to modelling the heating of evaporated droplets have been widely used in engineering applications. In the first approach the heat rate supplied to the droplets to raise their temperatures, q̇d, is derived from the requirement that droplet evaporation rates, inferred from steady-state equations for mass and heat balance, should be the same. The second approach is based on the direc...

A kinetic model for droplet heating and evaporation into a high pressure background gas (air) is described. This model is based on the introduction of the kinetic region around evaporating droplets, where the dynamics of molecules are described in terms of the Boltzmann equations for vapour and air. Both mass and heat transfer processes in this region are taken into account. The conditions at t...

An existing in-cylinder thermal regeneration concept for Diesel engines is examined for the roles of the porous insert motion and the fuel injection strategies on the fuel evaporation and combustion and on the engine efficiency. While the heated air emanating from the insert enhances fuel evaporation resulting in a superadiabatic combustion process (thus increasing thermal efficiency), the corr...

Combustion kinetics ...................................................................................................................................... 1 Physical mixing and its effects on ignition, propagation and extinction ...................................................... 2 Mixing ...........................................................................................................