A thermodynamic property formulation for air. I. Single-phase equation of state from 60 to 873 K at pressures to 70 MPa

Jacobsen, R. T.; Clarke, W. P.; Penoncello, Steven G.; McCarty, R.D.

doi:10.1007/bf00503868

Cited by 10 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where, m is the mass flow rate of helium, is the mean flow velocity of the two streams He U m (U,op = Uhollom Um)' and A the cross sectional area of each stream. The temperature of each stream was measured and the densities of air and helium were obtained from equations of state (McCarty 1973;Jacobsen et al 1990). The helium flow metering unit was designed based on a volumetric method (at constant outlet pressure), in which helium was delivered from a compressed supply having passed though an orifice (John 1984;Jitschin et al 1984).…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Detailed measurements of a statistically steady Rayleigh–Taylor mixing layer from small to high Atwood numbers

2010

View full text Add to dashboard Cite

The self-similar evolution to turbulence of a multi-mode miscible Rayleigh–Taylor (RT) mixing layer has been investigated for Atwood numbers 0.03–0.6, using an air–helium gas channel experiment. Two co-flowing gas streams, one containing air (on top) and the other a helium–air mixture (at the bottom), initially flowed parallel to each other at the same velocity separated by a thin splitter plate. The streams met at the end of the splitter plate, with the downstream formation of a buoyancy unstable interface, and thereafter buoyancy-driven mixing. This buoyancy-driven mixing layer experiment permitted long data collection times, short transients and was statistically steady. Several significant designs and operating characteristics of the gas channel experiment are described that enabled the facility to be successfully run for At ~ 0.6. We report, and discuss, statistically converged measurements using digital image analysis and hot-wire anemometry. In particular, two hot-wire techniques were developed for measuring the various turbulence and mixing statistics in this air–helium RT experiment. Data collected and discussed include: mean density profiles, growth rate parameters, various turbulence and mixing statistics, and spectra of velocity, density and mass flux over a wide range of Atwood numbers (0.03 ≤ At ≤ 0.6). In particular, the measured data at the small Atwood number (0.03–0.04) were used to evaluate several turbulence-model constants. Measurements of the root mean square (r.m.s.) velocity and density fluctuations at the mixing layer centreline for the large At case showed a strong similarity to lower At behaviours when properly normalized. A novel conditional averaging technique provided new statistics for RT mixing layers by separating the bubble (light fluid) and spike (heavy fluid) dynamics. The conditional sampling highlighted differences in the vertical turbulent mass flux, and vertical velocity fluctuations, for the bubbles and spikes, which were not otherwise observable. Larger values of the vertical turbulent mass flux and vertical velocity fluctuations were found in the downward-falling spikes, consistent with larger growth rates and momentum of spikes compared with the bubbles.

show abstract

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Detailed measurements of a statistically steady Rayleigh–Taylor mixing layer from small to high Atwood numbers

2010

View full text Add to dashboard Cite

show abstract

“…The estimated uncertainties in the proposed ideal-gas formulations for the density of dry and humid air are less than 0.2% under typical atmospheric temperature and pressure conditions (Jacobson, 2005). A Helmholtz function for dry air was published by Lemmon et al (2000), representing experimental data in the range 0-70 MPa and 60-873 K (reasonably predicting properties even up to 2000 MPa and 2000 K) as an extended revision of the previous equation by Jacobsen et al (1990), completing it with the ideal-gas contributions for the major air constituents. The most recent ideal-gas heat capacities are available from Helmholtz function formulations for Nitrogen (Span et al, 2000, quantum rigid rotor model for 20-500 K with 0.01% uncertainty), Oxygen (Stewart et al, 1991, from experimental data at 30-3000 K with a maximum deviation of 0.003 J mol −1 K −1 ) and Argon (Tegeler et al, 1999, us-ing the constant isobaric heat capacity c Ar,id P = 2.5R with an uncertainty below 0.01% up to 10 000 K).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties of sea air

et al. 2010

View full text Add to dashboard Cite

Abstract. Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphereocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS), and have been adopted in 2009 for oceanography by IOC/UNESCO.In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as "sea air" here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well.The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.

show abstract

“…For the construction of accurate equations, two routes may be considered. The one route is to correlate large data sets by equations with many substance-specific parameters (Bender, 1971; Jacobsen et al, 1990;Setzmann and Wagner, 1991). This approach yields very accurate equations, but the problem is already in the measurement of the required large data sets for pure fluids and even more for mixtures.…”

Section: Introductionmentioning

confidence: 99%