A thermodynamic property formulation for standard dry air based upon available experimental p-T, heat capacity, speed of sound, and vapor-liquid equilibrium data is presented. This formulation is valid for liquid, vapor, and supercritical air at temperatures from the solidification point on the bubble-point curve ͑59.75 K͒ to 2000 K at pressures up to 2000 MPa. In the absence of reliable experimental data for air above 873 K and 70 MPa, air properties were predicted from nitrogen data in this region. These values were included in the determination of the formulation to extend the range of validity. Experimental shock tube measurements on air give an indication of the extrapolation behavior of the equation of state up to temperatures and pressures of 5000 K and 28 GPa. The available measurements of thermodynamic properties of air are summarized and analyzed. Separate ancillary equations for the calculation of dew and bubble-point pressures and densities of air are presented. In the range from the solidification point to 873 K at pressures to 70 MPa, the estimated uncertainty of density values calculated with the equation of state is 0.1%. The estimated uncertainty of calculated speed of sound values is 0.2% and that for calculated heat capacities is 1%. At temperatures above 873 K and 70 MPa, the estimated uncertainty of calculated density values is 0.5% increasing to 1.0% at 2000 K and 2000 MPa. In addition to the equation of state for standard air, a mixture model explicit in Helmholtz energy has been developed which is capable of calculating the thermodynamic properties of mixtures containing nitrogen, argon, and oxygen. This model is valid for temperatures from the solidification point on the bubble-point curve to 1000 K at pressures up to 100 MPa over all compositions. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the real gas contribution, and the contribution from mixing. The contribution from mixing is given by a single generalized equation which is applied to all mixtures used in this work. The independent variables are the reduced density and reduced temperature. The model may be used to calculate the thermodynamic properties of mixtures at various compositions including dew and bubble-point properties and critical points. It incorporates the most accurate published equation of state for each pure fluid. The mixture model may be used to calculate the properties of mixtures generally within the experimental accuracies of the available measured properties. The estimated uncertainty of calculated properties is 0.1% in density, 0.2% in the speed of sound, and 1% in heat capacities. Calculated dew and bubble-point pressures are generally accurate to within 1%.

The International Association for the Properties of Water and Steam (IAPWS) encouraged an extensive research effort to update the IAPS Formulation 1985 for the Viscosity of Ordinary Water Substance, leading to the adoption of a Release on the IAPWS Formulation 2008 for the Viscosity of Ordinary Water Substance. This manuscript describes the development and evaluation of the 2008 formulation, which provides a correlating equation for the viscosity of water for fluid states up to 1173K and 1000MPa with uncertainties from less than 1% to 7% depending on the state point.

The development of surrogate mixtures that represent gasoline combustion behavior is reviewed.1 Combustion chemistry behavioral targets that a surrogate should accurately reproduce, particularly for emulating homogeneous charge compression ignition (HCCI) operation, are carefully identified. Both short and long term research needs to support development of more robust surrogate fuel compositions are described. Candidate component species are identified and the status of present chemical kinetic models for these components and their interactions are discussed. Recommendations are made for the initial components to be included in gasoline surrogates for near term development. Components that can be added to refine predictions and to include additional behavioral targets are identified as well. Thermodynamic, thermochemical and transport properties that require further investigation are discussed.

No abstract

This article describes a 10-year cooperative effort between the U.S. National Institute of Standards and Technology (NIST) and five major journals in the field of thermophysical and thermochemical properties to improve the quality of published reports of experimental data. The journals are Journal of Chemical and Engineering Data, The Journal of Chemical Thermodynamics, Fluid Phase Equilibria, Thermochimica Acta, and International Journal of Thermophysics. The history of this unique cooperation is outlined, together with an overview of software tools and procedures that have been developed and implemented to aid authors, editors, and reviewers at all stages of the publication process, including experiment

A thermodynamic model incorporating a fundamental equation of state for the Helmholtz free energy of the mixture ͕waterϩammonia͖ is presented which covers the thermodynamic space between the solid-liquid-vapor boundary and the critical locus. It is also valid in the vapor and liquid phases for pressures up to 40 MPa. It represents vapor-liquid equilibrium properties with an uncertainty of Ϯ0.01 in liquid and vapor mole fractions. Typical uncertainties in the single-phase regions are Ϯ0.3% for the density and Ϯ200 J mol Ϫ1 for enthalpies. Details of the data selection and the optimization process are given. The behavior of the fundamental equation of state is discussed in all parts of the thermodynamic space.

The International Association for the Properties of Water and Steam (IAPWS) encouraged an extensive research effort to update the IAPS Formulation 1985 for the Thermal Conductivity of Ordinary Water Substance, leading to the adoption of a Release on the IAPWS Formulation 2011 for the Thermal Conductivity of Ordinary Water Substance. This paper describes the development and evaluation of the 2011 formulation, which provides a correlating equation for the thermal conductivity of water for fluid states from the melting temperature up to 1173 K and 1000 MPa with uncertainties from less than 1% to 6%, depending on the state point.

No abstract