Liquid density measurement of n-decane with a random temperature signal cross-correlation densimeter at high temperatures and pressures

Abstract

A novel densimeter based on a random temperature signal cross-correlation method was designed and constructed. Liquid densities of n-decane were measured at T = (293.2–493.5) K and p = (0.1–20.0) MPa. The expanded uncertainties in liquid density measurements are 1.16%, with a confidence level of 0.95 (k = 2). This experimental study provides new n-decane densities to examine Lemmon's equations' accuracy at high temperatures and pressures, where few experimental densities are yet to be reported. The experimental data's average absolute deviation (AAD) and maximum absolute deviation (MAD) compared to the fitted data from Lemmon's equations are 0.15% and 0.43%, respectively. The liquid densities at high temperatures and pressures were fitted with a Tait-type equation. The physical meaning and temperature behavior of the Tait correlation's parameters were discussed. The average absolute deviation (AAD) between the experimental and calculated data from the Tait-type equation is 0.23%.