Light naphtha, or low octane gasoline, is a highly volatile intermediate hydrocarbon produced during the refining process. Due to its low energy requirements for production, use of light naphtha in combustion engines for automotive applications is currently being investigated. This paper focuses on heating and evaporation of single light naphtha droplet to understand the underlying physics during evaporation process. The considered model takes into account the effect of finite thermal conductivity, finite liquid diffusivity and recirculation inside the droplet due to relative motion with ambient air, referred to as the effective thermal conductivity/effective diffusivity (ETC/ED) model. The real composition of light naphtha is considered. The vaporization characteristics of light naphtha are compared with those of its distillation-based surrogate from literature. This surrogate reasonably matches the distillation curve and underpredicts ignition delay time of light naphtha by 10%. A comparison between the predicted droplet lifetime and surface temperature of light naphtha and those of surrogate shows that the surrogate overpredcits the droplet lifetime by 12% and the droplet surface temperature is significantly different from that of light naphtha. Four new physical surrogates, Surr1-New, Surr2-New, Surr3-New and Surr4-New, are proposed to match vaporization characteristics of light naphtha. The predicted droplet surface temperature and evaporation time of the first three surrogate are within 1% difference from those of light naphtha while the droplet surface temperature of the fourth surrogate, Surr4_New, is 4% off the this of light naphtha. The molecular weight and hydrogen to carbon ratio (HC) of new surrogates are close to those of light naphtha. While the research octane number (RON) for Surr2-New (RON = 64.1), Surr3-New (RON = 62.7) and Surr4-New (RON = 62.5) are closer to light naphtha (68) than RON of Surr1-New (RON = 56.9).
|Original language||English (US)|
|Title of host publication||13th International Conference on Liquid Atomization and Spray Systems, ICLASS 2015|
|Publisher||ILASS - Europe, Institute for Liquid Atomization and Spray Systems|
|State||Published - Jan 1 2015|