A thermodynamic property formulation for ethylene from the freezing line to 450 K at pressures to 260 MPa
A new thermodynamic property formulation based upon a fundamental equation explicit in Helmholtz energy of the form A = A(p,T) for ethylene from the freezing line to 450 K at pressures to 260 MPa is presented. A vapor pressure equation, equations for the saturated liquid and vapor densities as functions of temperature, and an equation 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-p-T data, saturated liquid and saturated vapor density data to define the phase equilibrium criteria for coexistence, C /SUB v/ data, velocity of sound data, and second virial coefficient. The fundamental equation and the derivative functions for calculating internal energy, enthalphy, entropy, isochoric heat capacity (C /SUB v/ ), isobaric heat capacity (C /SUB p/ ), and velocity of sound are included. The fundamental equation reported here may be used to calculate pressures and densities with an uncertainty of +/-0.1%, heat capacities within +/-3%, and velocity of sound values within +/-1%, except in the region near the critical point. The fundamental equation is not intended for use near the critical point. This formulation is proposed as part of a new international standard for thermodynamic properties of ethylene.
- Research Organization:
- Univ. of Idaho, Moscow, ID
- OSTI ID:
- 6909436
- Report Number(s):
- CONF-850617-
- Journal Information:
- Int. J. Thermophys.; (United States), Journal Name: Int. J. Thermophys.; (United States) Vol. 7:3; ISSN IJTHD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ALKENES
CALIBRATION STANDARDS
DENSITY
EQUATIONS
EQUATIONS OF STATE
EQUILIBRIUM
ETHYLENE
FLUID MECHANICS
FLUIDS
GASES
HYDROCARBONS
HYDRODYNAMICS
LIQUIDS
MECHANICS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
SATURATION
SOUND WAVES
STANDARDS
THERMODYNAMIC PROPERTIES
VAPORS
VELOCITY
WAVE PROPAGATION