Viscosity of Biodiesel As a Function of Temperature, Pressure and Composition

Viscosity is a significant physical property in the design of injection systems for diesel engines. Low-percentage blends of biodiesel and diesel fuel may be used in diesel engines without modification, and with few modifications, higher percentage blends as well as pure biodiesel may be used.  Injectors often reach pressures greater than 100 MPa.  Predicting the differences in biodiesel viscosities from different feedstocks at high pressures and temperatures will aid in the development of more efficient and environmentally-friendly engines.  Measured data, and data from the literature, were used to regress parameters that allow the accurate (+/- 5%) prediction of dynamic viscosity for a wide range of temperatures (283.15 to 373.15K) and pressures (0.1 to 131 MPa) given the fatty acid methyl ester composition of the fuel.