Predicting specific gravity and viscosity of biodiesel fuels

Biodiesel is a promising non-toxic and biodegradable alternative fuel in transport sector. Of all the biodiesel properties, specific gravity and viscosity are the most significant for the effects they have on the utilization of biodiesel fuels in unmodified engines. This paper presents models, which have been derived from experimental data, for predicting the specific gravity and dynamic viscosity of biodiesel at various temperatures and fractions. In addition a model has also been developed to predict the dynamic viscosity of the biodiesel from its specific gravity. In order to develop these models, the specific gravity and viscosity of rapeseed oil biodiesel, corn oil biodiesel and waste oil biodiesel blends (0B, 5B, 10B, 20B, 50B, 75B, and 100B) were tasted across a temperature range of 15.6oC to 90oC using EN ISO 3675:1998 and EN ISO 3104:1996 test procedures. Evaluation of the proposed models shows it has same order of accuracy as the other models published in literature.