Isochoric Heat Capacity Measurements for Heavy Water Near the Critical Point

Published

May 1, 2002

Author(s)

N. G. Polikhronidi, I M. Abdulagatov, Joe W. Magee, G. V. Stepanov

Abstract

Isochoric heat capacity measurements of D₂0 are presented as a function of temperature at fixed densities of 319.60, 398.90, 431.09 and 506.95 kg m^-3. The measurements cover a range of temperatures from 551 to 671 K and pressures up to 32 Mpa. The coverage includes one- and two-phase states and the coexistence curve near the critical point of D₂0. We used a high-temperature, high-pressure, adiabatic, and nearly constant-volume calorimeter for the measurements. Uncertainties of the heat capacity measurements are estimated to be 2 to 3%. Temperatures at saturation T_S(P) were measured isochorically using a quasi-static thermogram method. The uncertainty of the phase transition temperature measurements is about 0.02 K. The measured C_V data for D₂0 were compared with values predicted from a parametric crossover equation of state and six-term Landau expansion crossover model. The critical behavior of second temperature derivatives of the vapor pressure and chemical potential were studied using measured two-phase isochoric heat capacities. From measured isochoric heat capacities and saturated densities for heavy water, the values of asymptotic critical amplitudes were estimated. It is shown that the critical Parameters (critical temperature and critical density) adopted by IAPWS are consistent with the Ts-Ps measurements for D₂O near the critical point.

Citation

International Journal of Thermophysics

Volume

23

Issue

No. 3

Pub Type

Journals

Keywords

adiabatic calorimeter, coexistence curve, critical amplitudes, critical point, crossover equation of state, density, isochoric heat capacity, light and heavy water

Citation

Polikhronidi, N. , Abdulagatov, I. , Magee, J. and Stepanov, G. (2002), Isochoric Heat Capacity Measurements for Heavy Water Near the Critical Point, International Journal of Thermophysics (Accessed May 3, 2025)