Robert D. McCarty

The Viscosity and Thermal Conductivity Coefficients for Dense Gaseous and Liquid Argon, Krypton, Xenon, Nitrogen, and Oxygen

Data for the viscosity and thermal conductivity coefficients of argon, nitrogen, and oxygen have been critically evaluated. A functional form to represent the data has been proposed. The function is basically the same for both coefficients. The critical point enhancement in the thermal conductivity coefficient is included. Transport properties of krypton and xenon are calculated by means of the principle of corresponding states. Tables of values are presented in the range from about the triple point temperature to 500 K for pressures up to 100 MPa. Care has been taken to ensure that the calculated values are consistent with reliable equation‐of‐state data and also with dilute gas transport coefficients previously determined. The uncertainties of the tabulated coefficients are discussed in the text. The correlation further serves to clarify the state of the art concerning transport data and experiment and to emphasize gaps in data coverage.

A New Wide Range Equation of State for Helium

A new correlation and computer code have been developed for helium. The correlation covers the temperature range of 0.8 to 1500 K using two equations of state, one for superfluid helium and another for the normal fluid. The equation of state for the normal fluid is valid for temperatures between 2 and 1500 K and for pressures up to 2000 MPa. The new normal fluid equation of state achieves increased accuracy in some regions of pressure and temperature, but not in others. There are unique problems involved in the correlation of helium data which prevent obtaining the accuracies which are more easily obtained for the properties of other fluids. Only the normal fluid equations are given here.

Thermophysical properties of Helium-4 from 0.8 to 1500 K with pressures to 2000 MPa

Tabular summary data of the thermophysical properties of fluid helium are given for temperatures from 0.8 to 1500 K, with pressures to 2000 MPa between 75 and 300 K, or to 100 MPa outside of this temperature band. Properties include density, specific heats, enthalpy, entropy, internal energy, sound velocity, expansivity, compressibility, thermal conductivity, and viscosity. The data are calculated from a computer program which is available from the National Institute of Standards and Technology. The computer program is based on carefully fitted state equations for both normal and superfluid helium.

Thermodynamic Properties of Ethylene from the Freezing Line to 450 K at Pressures to 260 MPa

A new fundamental equation explicit in Helmholtz energy for thermodynamic properties of ethylene from the freezing line to 450 K at pressures to 260 MPa is presented. Independent equations for the vapor pressure for the saturated liquid and vapor densities as functions of temperature, and for the ideal gas heat capacity are also included. The fundamental equation was selected from a comprehensive function of 100 terms on the basis of a statistical analysis of the quality of the fit. The coefficients of the fundamental equation were determined by a weighted least‐squares fit to selected P‐ρ‐T data, saturated liquid, and saturated vapor density data to define the phase equilibrium criteria for coexistence, Cv data, velocity of sound data, and second virial coefficient data. The fundamental equation and the derivative functions for calculating internal energy, enthalpy, entropy, isochoric heat capacity (Cv), isobaric heat capacity (Cp), and velocity of sound are included. Tables of thermodynamic properties o...

Isochoric (p, Vm, x, T) measurements on (methane + ethane) from 100 to 320 K at pressures to 35 MPa☆

Abstract Comprehensive isochoric (p, Vm, x, T) values have been obtained for {xCH4 + (1 − x)C2H6} with x = 0.35, 0.50, and 0.69 at amount-of-substance densities from 1 to 25 mol·dm−3. The measurements for each composition cover a temperature range from approximately 100 to 320 K at pressures up to 35 MPa. For each mixture the results have been fit to a 32-term modified Benedict-Webb-Rubin equation of state. Further development of the extended corresponding-states model has been accomplished using the results presented here. Comparisons with values from independent sources have been made where possible.

The viscosity and thermal conductivity coefficients for dense gaseous and liquid methane

Data for the viscosity and thermal conductivity coefficients of dense gaseous and liquid methane have been evaluated. Selected data were fitted to a function derived in our previous work and tables of values were generated for temperatures from 95 to 500 K and for pressures up to 50 MPa (∠500 atm). The uncertainties of the tabular values are estimated to be approximately 3% and 5% for the viscosity and thermal conductivity coefficients, respectively. The contribution for the thermal conductivity enhancement in the critical region is included in the tables. Care has been taken to ensure that the calculated values are consistent with reliable equation‐of‐state data and also with dilute gas transport coefficients determined previously.

Equations for the viscosity and thermal conductivity coefficients of methane

Abstract An equation is proposed to calculate the viscosity and thermal conductivity coefficients of methane from the dilute gas to the dense liquid. The range of validity of the equation is approximately 95–400 K for pressures up to 50 MPa (∼500 atm). The reliabilities of the coefficients calculated are estimated at approximately 2% and 5% for the viscosity and thermal conductivity coefficients, respectively. The equation includes a contribution for the thermal conductivity enhancement in the critical region.

Mathematical models for the prediction of liquefied-natural-gas densities☆

Abstract Three mathematical models of the equation of state for liquid mixtures simulating liquefied natural gas (LNG) are discussed and compared. The adjustable parameters for each model have been optimized using the same set of experimental data, consisting of over 280 new ( p , V , T , x ) points taken at the National Bureau of Standards in Boulder, Colorado. It is estimated that each of the models will predict LNG densities over its range of validity to within 0.1 per cent of the true values, given the pressure, temperature, and composition of the mixture. Deviation plots and a detailed performance evaluation are given for each model. The range of validity varies slightly among the models but in general the range of the study included the saturated liquid from 90 to 135 K.

Speed-of-sound measurements for nitrogen gas at temperatures from 80 to 350 K and pressures to 1.5 MPa

Speeds of sound for nitrogen gas have been measured at pressures from 0.03 to 1.5 MPa on 16 isotherms from 80 to 350 K. Measurements were made in a fixed-path acoustic cavity using variable-frequency electrostatic transducers operating between 1 and 30 kHz. Correction for boundary-layer effects were made using existing values of thermodynamic properties.

Low-density isochoric (p, V, T) measurements on (nitrogen + methane)

Abstract Isochoric (p, V, T) measurements have been made on three mixtures of nitrogen and methane (0.29N2 + 0.71CH4), (0.50N2 + 0.50CH4), and (0.68N2 + 0.32CH4) at densities of 1 to 6 mol·dm−3. The three isochores for each mixture cover a temperature range from approximately 150 to 320 K up to a maximum pressure of 16 MPa. Comparisons with other experimental results and with values calculated from an extended corresponding-states model are discussed.