Speed of Sound in Hydrocarbon-Fatty Acid Methyl Ester Blends: Experimental Investigation and Combining Rule Development

This paper presents a comprehensive investigation into predictive modeling of the speed of sound in hydrocarbon-fatty acid methyl ester blends. Experimental work was first conducted at T = 303.15 K in 48 binary systems comprising hydrocarbons from various families, including n-alkanes, iso-alkanes, naphthenes, and aromatics, combined with different fatty acid methyl esters (caprate, myristate, stearate, or oleate). From these measurements, a combining rule capable of predicting the speed of sound in such binary mixtures based on pure component data was proposed. Then, the study extended beyond traditional binary systems to encompass multicomponent mixtures. Finally, through extensive experimentations of the speed of sound as a function of temperature, the effect of temperature on the proposed combining rule parameter was established. The performance of the combining rule was validated against experimental data, revealing a mean deviation of only 0.2%.