Measurements and empirical correlations in predicting biodiesel-diesel blends' viscosity and density

- Density-biodiesel content variation is well correlated by linear model.
- Exponential equation is the best model for density-temperature variation.
- Rational model is the most proper one to predict viscosities of fuel blends.
- Power model is the best one to characterize viscosity vs. temperature variation.
- Two-term power model better correlates density-viscosity variation.

One of the attempts to limit the use of fossil fuels in automobiles is to replace them partially or totally with clean and renewable fuels. Among renewable fuels, biodiesel has emerged as an important alternative to petroleum diesel fuel. Therefore, in this study, first, biodiesel was produced from hazelnut oil, which is agricultural product at Black Sea region of Turkey, by means of transesterification reaction. The produced biodiesel was blended with Ultra Force Euro diesel fuel at the volume ratios of 5, 10, 15, 20, 50 and 75% which are called as B5, B10, B15, B20, B50 and B75 as usual, respectively. Second, the densities and kinematic viscosities of each blends were measured at average climate conditions as 10, 20, 30 and 40 °C by following international ISO 4787 and DIN 53015 standards. Finally, new models were derived through the least squares regression method for density-temperature, kinematic viscosity-biodiesel fraction, kinematic viscosity-temperature and kinematic viscosity-density relationships, and compared with well-known models previously published in literature to determine the well-matched models.