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Speed of sound measurements and a fundamental equation of state for cyclopentane



Eric W. Lemmon, Holger Gedanitz, Maria J. Davila


The speed of sound in liquid cyclopentane has been measured in the temperature range from (258 to 353) K at pressures up to 30 MPa (42 data points) using a pulse-echo method with a double path type sensor. The expanded overall uncertainty (k = 2) in the speed of sound measurements is estimated to be 0.2 %. A function for the speed of sound with inputs of temperature and pressure has been fitted from the experimental results. The new speed of sound data along with available literature data were used to develop a fundamental Helmholtz equation of state for cyclopentane. Typical uncertainties of properties calculated using the new equations are 0.2 % in density in the liquid phase, 1 % in heat capacity, 0.2 % in liquid phase sound speed, and 0.5 % in vapor pressure. The equation of state is valid from the triple point temperature of 179.7 K to 550 K with pressures to 250 MPa.
Journal of Chemical and Engineering Data


Cyclopentane, Speed of sound, Pulse-echo, Equation of state


Lemmon, E. , Gedanitz, H. and Davila, M. (2015), Speed of sound measurements and a fundamental equation of state for cyclopentane, Journal of Chemical and Engineering Data, [online], (Accessed April 16, 2024)
Created April 22, 2015, Updated June 2, 2021