Thermodynamic Properties of Nitrogen from the Freezing Line to 2000 K at Pressures to 1000 MPa

Abstract

A new fundamental equation explicit in Helmholtz energy for thermodynamic properties of nitrogen from the freezing line to 2000 K at pressures to 1000 MPa is presented. New independent equations for the vapor pressure and for the saturated liquid and vapor densities as functions of temperature 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, and velocity of sound 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 of nitrogen are given for liquid and vapor states within the range of validity of the fundamental equation. The fundamental equation reported here may generally be used to calculate pressures and densities with an uncertainty of ±0.1%, heat capacities within ±3%, and velocity of sound values within ±1%. Comparisons of calculated properties to experimental data are included to verify the accuracy of the formulation.

Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides

“…33 Azide precursors can also provide high nitrogen activity for nitride synthesis, as they decompose as N 3 − (g) → N 2 + N + e − , yielding a "free" highly reactive nitrogen atom. 38 Nitrogen fugacity under pressures up to 50 GPa was extrapolated from thermochemical data 39 to have a chemical potential up to +15 k B T/N 2 above the N 2 standard state (∼1.25 eV/N at 2000 K). 40 Another extreme case of reactive nitrogen precursors is atomic nitrogen, which can be made from the cracking of N 2 molecules in the plasma of reactive-sputtering processes.…”

Calculation of Thermal Pressure Coefficient of Lithium Fluid by pVT Data

“…Most modern wide-range, high-accuracy equations of state for pure fluid properties are fundamental equations explicit in the Helmholtz energy as a function of density and temperature. All single-phase thermodynamic properties can be calculated as derivatives of the Helmholtz energy [9][10][11][12][13][14][15].…”

“…The other work is an expression which is known as thermal pressure coefficient of dense fluids (Ar, N 2 , CO, CH 4 , C 2 H 6 , n-C 4 H 10 , iso-C 4 H 10 , C 6 H 6 , and C 6 H 5 -CH 3 ) [9][10][11][12][13][14][15]. Only, pVT experimental data have been used for the calculation of thermal pressure coefficients [16].…”

Rheological Behavior and Empirical Model of Simulated Foaming Slag

“…This consists of an outer cylinder of acrylic pipe, and an inner rotating spindle from a commercially available viscometer (Brookfield digital viscometer DVII+) The outer acrylic cylinder contains a porous bottom (Fine porous alumina, Krosaki Harima Corp.), which allows N 2 gas bubbles © 2014 ISIJ to be generated in the liquid phase silicone oil (KF-96, ShinEtsu Chemical Co., Ltd.) contained within. As previously mentioned, CO gas is generated in the actual converter process, but N 2 gas exhibits quite similar thermophysical properties to CO gas, [8][9][10] as density, viscosity, specific heat, etc., because of their similarity in bonding nature. Thus, in the present study, the variation in apparent viscosity with different gas species can be negligibly small.…”