The purpose of the present study is to improve the current prediction capabilities of the entrainment fraction in horizontal gas-liquid flow. Since it is recognized that waves at the gas-liquid interface are the main source of entrainment, an experimental and theoretical work has been carried out to characterize the waves at the gas-liquid interface and to develop a model for entrainment calculations based on such characteristics. The model consists of three sub-models, namely, onset of entrainment, maximum entrainment and entrainment values in between. The onset of entrainment model determines the conditions at which the gas starts shearing the wave crests through a force balance between drag and surface tension forces. The maximum entrainment model provides the maximum fraction of liquid that can be entrained at high gas velocities by integration of the turbulent velocity profile to a determined dimensionless film thickness within the buffer sub layer. The entrainment fraction in between onset and maximum boundaries is calculated from an equilibrium between atomization and deposition rates. The atomization rate is calculated by first determining the wave mass flux in the liquid film and second by calculating the fraction of a single wave that is sheared by the gas through a force balance. The deposition rate is calculated as a linear function of the droplet concentration in the gas. Closure relationships have been developed from data for wave celerity, frequency, amplitude and width which are used in the entrainment model. A review of the most used correlations for calculating the entrainment fraction is presented and their performance evaluated. The present model shows better prediction than available models when compared to the acquired experimental data and the available experimental data in the literature.

This paper presents P-F-T data for pure carbon dioxide measured with a high-pressure single-sinker magnetic suspension densimeter (MSD). The data cover four isotherms (310, 350, 400, 450) K. The MSD technique yields data with less than 0.03 % relative uncertainty over the pressure range of (10 to 200) MPa. A comparison of the experimental data to the equation of state developed by Span and Wagner indicates that the equation and the data are consistent within the low range of pressure. The reference equation has a relative uncertainty of ( 0.03 % to ( 0.05 % below 30 MPa. At higher pressures, the density predictions of this model agree with the experimental data with a maximum relative deviation of 0.1 %.

This paper reports PFT data measured with a high-pressure, single-sinker, magnetic-suspension densimeter (MSD) from (300 to 450) K up to 180 MPa. Our MSD technique yields accurate data, with less than 0.05 % relative uncertainty, over the pressure range of (10 to 200) MPa. The experimental data compare well to the Setzmann and Wagner equation of state as implemented in RefProp 8.0. These methane density data are consistent with the low range of pressure predicted by RefProp 8.0 that has a relative uncertainty of 0.03 % up to 12 MPa and 0.07 % up to 50 MPa. The density predictions of this model agree well with previous data at higher pressures. The equation predicts data with almost the same uncertainty as the experimental data up to 180 MPa. These PFT data also allow reliable determination of both second and third virial coefficients.

Work reported in this paper is the continuation of a previous work (Atilhan et al. J. Chem. Eng. Data 2011, 56, 212–221) and reports measurements of density and phase envelope characteristics of three synthetic natural gas-like mixtures. These mixtures consist of primarily 0.9000 methane in mole fraction and variable amounts of ethane, propane, 2-methylpropane, butane, 2-methylbutane, and pentane as well as the presence or absence of nitrogen and carbon dioxide. A high-pressure single-sinker magnetic suspension densimeter was used to measure the density of the mixtures along three isotherms at (250, 350, and 450) K with pressures up to 150 MPa. Density measurements are compared to the GERG04 and AGA-8 equations of state, which are the two leading models used for natural gas density predictions. Predictions from both equations have a similar agreement with the data, yet it is observed that GERG04 model shows better performance in predictions with deviations less than around 0.2 % at different temperatures (T = 350 K and T = 450 K) and pressures (p > 20 MPa). An isochoric apparatus was used for phase envelope experiments, and the data are compared to several cubic biparametric, cubic triparametric, and molecular-based equation of states. Equation-of-state predictions for the mixtures and comparison with the experimental data are shown. Equation-of-state predictions show substantial deviations around the entire phase envelope for the third mixture, in which the nitrogen and carbon dioxide have not been included.

The magnetic suspension densimeter (MSD) is a sophisticated, stateof-the-art device that provides extremely accurate results for density measurements. The MSD uses a magnetic technique to couple a mass inside a measurement cell with an external mass balance for mass measurement. This article presents a force transmission error (FTE) analysis for a high-pressure, single-sinker MSD. Due to the magnetic working principle of the apparatus, magnetic properties of the high-pressure cell and external magnetic fields affect the measurements slightly. For the analysis, McLinden et al. suggest making measurements using two different sinkers, a titanium sinker and a copper sinker, having the same mass. The measurements cover densities for methane, ethane, carbon dioxide and nitrogen over the temperature range from 265 K to 450 K (±5 mK stability) up to 180 MPa (uncertainty of 0.01 % full scale: 200 MPa). Comparing and manipulating the measurements permit determination of apparatus and fluid specific effects that contribute to the FTE. For this MSD, the apparatus effect is about 200 ppm, which effectively masks any fluid specific effect. A comprehensive analysis of the FTE produces a uniform deviation for density values of about 0.05 % at 2σ across the full range of pressure.