Simplified Correlations for Hydrocarbon Gas Viscosity and Gas Density - Validation and Correlation of Behavior Using a Large-Scale Database

2002 ◽  
Author(s):  
F.E. Londono ◽  
R.A. Archer ◽  
T.A. Blasingame
Keyword(s):  
Large Scale ◽  
Gas Density ◽  
Gas Viscosity ◽  
Hydrocarbon Gas

Correlations for Hydrocarbon Gas Viscosity and Gas Density - Validation and Correlation of Behavior Using a Large-Scale Database

2005 ◽  
Vol 8 (06) ◽  
pp. 561-572 ◽  
Author(s):  
Fabio E. Londono ◽  
Rosalind A. Archer ◽  
Thomas A. Blasingame
Keyword(s):  
Molecular Weight ◽  
Large Scale ◽  
Gas Mixtures ◽  
Large Database ◽  
Hydrocarbon Gases ◽  
Gas Density ◽  
Gas Viscosity ◽  
New Models ◽  
Hydrocarbon Gas ◽  
Temperature And Pressure

Summary The focus of this work is on the behavior of hydrocarbon-gas viscosity and gas density. The viscosity of hydrocarbon gases is a function of pressure, temperature, density, and molecular weight, while the gas density is a function of pressure, temperature, and molecular weight. This work presents new approaches for the prediction of gas viscosity and gas density for hydrocarbon gases over practical ranges of pressure, temperature, and composition. These correlations can be used for any hydrocarbon-gas production or transportation operations. In this work, we created a large database of measured gas viscosity and gas density. This database was used to evaluate existing models for gas viscosity and gas density. We also provide new models for gas density and gas viscosity, as well as optimization of existing models, using our new database. The objectives of this research are as follows:• To create a large-scale database of measured gas-viscosity and gas-density data. This database will contain all the information necessary to establish the applicability of various models for gas density and gas viscosity over a widerange of pressures and temperatures.• To evaluate a number of existing models for gas viscosity and gas density.• To develop new models for gas viscosity and gas density using our research database; these models are proposed and validated. For this study, we created a large database from existing sources available in the literature. The properties in our database include composition, viscosity, density, temperature, pressure, pseudo reduced properties, and the gas compressibility factor. We use this database to evaluate the applicability of existing models used to determine hydrocarbon-gas viscosity and hydrocarbon-gas density (or, more specifically, the gas z-factor). Finally, we developed new models and calculation approaches to estimate the hydrocarbon-gas viscosity, and we also provide an optimization of the existing equations of state (EOS) typically used for for the calculation of the gas z-factor. Introduction Hydrocarbon-Gas Viscosity. NIST—SUPERTRAP Algorithm. The state-of-the-art mechanism for the estimation of gas viscosity is most likely the computer program SUPERTRAP, developed at the U.S. Natl. Inst. of Standard sand Technology (NIST). SUPERTRAP was developed from pure-component and mixture data and is stated to provide estimates within engineering accuracy from the triple point of a given substance to temperatures of 1,340.33°F and pressures of 44,100 psia. Because the SUPERTRAP algorithm requires the composition for a particular sample, it generally would not be suitable for applications in which only the mixture gas gravity and compositions of any contaminants are known. Carr et al. Correlation. Carr et al. developed a two-step procedure to estimate hydrocarbon-gas viscosity. The first step is to determine the gas viscosity at atmospheric conditions (i.e., a reference condition). Once estimated, the viscosity at atmospheric pressure is then adjusted to conditions at temperature and pressure using a second correlation. The gas viscosity can be estimated with graphical correlations or using equations derived from these figures. Jossi et al. Correlation. Jossi et al. developed a relationship for the viscosity of pure gases and gas mixtures; this correlation includes pure components such as argon, nitrogen, oxygen, carbon dioxide, sulfur dioxide, methane, ethane, propane, butane, and pentane. This "residualviscosity" relationship can be used to predict gas viscosity with the "reduced"density at a specific temperature and pressure, as well as the molecular weight. The critical properties of the gas (i.e., the critical temperature and critical pressure) are also required. Our presumption is that the Jossi et al. correlation (or at least a similar type of formulation) can be used for the prediction of viscosity for pure hydrocarbon gases and hydrocarbon-gas mixtures. We will note that this correlation is rarely used for hydrocarbon gases (other correlations are preferred); however, we will consider the formulation given by Jossi etal. as a potential model for the correlation of hydrocarbon-gas-viscosity behavior.

scholarly journals The Formation of Discontinuities in Gas Flows in the ISM and its Relation to the Galactic Synchrotron Radio Emission

1990 ◽  
Vol 140 ◽  
pp. 159-162
Author(s):  
V.G. Berman ◽  
L.S. Marochnik ◽  
Yu.N. Mishurov ◽  
A.A. Suchkov
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Radio Emission ◽  
Large Scale ◽  
Field Energy ◽  
Gas Flows ◽  
Interstellar Gas ◽  
Gas Density ◽  
Magnetic Field Energy ◽  
Wide Range

We show that large–scale motions of the interstellar gas, such as those associated with galactic density waves, easily develop, over a wide range of scales, shocks and discontinuities which are expected to generate turbulence. The latter is supposed to evoke diffusion of magnetic fields and cosmic rays on scales down to a few parsecs. We suggest that these processes may be of major importance in discussions of interconnections between the observed radio emission of the disks of spiral galaxies and the gas density distribution within them. In particular, we predict that the density of cosmic rays and magnetic field energy must be much less contrasted (on scales of ~1 pc and up to the scales of galactic shocks) than the gas density, hence the synchrotron radio emission is not as contrasted as is predicted under the hypothesis of a fully frozen-in magnetic field.

Analysis of results from large scale hydrocarbon gas explosions

2000 ◽  
Vol 13 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Murray J Shearer ◽  
Vincent H.Y Tam ◽  
Brian Corr
Keyword(s):  
Large Scale ◽  
Gas Explosions ◽  
Analysis Of Results ◽  
Hydrocarbon Gas

scholarly journals Large-scale fragmentation of gas cloud rotating at the Galactic center

1991 ◽  
Vol 147 ◽  
pp. 215-217
Author(s):  
M. Fujimoto ◽  
Y. Tatematsu
Keyword(s):  
Gravitational Potential ◽  
Large Scale ◽  
Galactic Center ◽  
Major Axis ◽  
Matter Density ◽  
The Self ◽  
Dynamical Structure ◽  
Gas Density ◽  
Self Gravity ◽  
Gas Cloud

A rotating and slowly-contracting gas cloud is followed in the deep gravitational potential of the galactic center. When the gas density increases as high as (102 — 103)H2 cm—3, which is more than twenty times as large as the background matter density, the self-gravity of the cloud becomes dominant to govern its dynamical structure. The cloud elongates and then splits into two separated objects, as observed at the centers of IC342, NGC6946, and Maffei 2 where we have two symmetric peaks on the major axis of the 12CO (J=1-0) cloud.

scholarly journals Two mechanisms of droplet splashing on a solid substrate

2017 ◽  
Vol 835 ◽  
pp. 1065-1086 ◽  
Author(s):  
Zhen Jian ◽  
Christophe Josserand ◽  
Stéphane Popinet ◽  
Pascal Ray ◽  
Stéphane Zaleski
Keyword(s):  
Phase Diagram ◽  
Numerical Simulations ◽  
Solid Substrate ◽  
Dominant Effect ◽  
Gas Density ◽  
Gas Phases ◽  
Gas Viscosity ◽  
Small Correction ◽  
Gas Layer ◽  
Gas Effect

We investigate droplet impact on a solid substrate in order to understand the influence of the gas in the splashing dynamics. We use numerical simulations where both the liquid and the gas phases are considered incompressible in order to focus on the gas inertial and viscous contributions. We first confirm that the dominant gas effect on the dynamics is due to its viscosity through the cushioning of the gas layer beneath the droplet. We then describe an additional inertial effect that is directly related to the gas density. The two different splashing mechanisms initially suggested theoretically are observed numerically, depending on whether a jet is created before or after the impacting droplet wets the substrate. Finally, we provide a phase diagram of the drop impact outputs as the gas viscosity and density vary, emphasizing the dominant effect of the gas viscosity with a small correction due to the gas density. Our results also suggest that gas inertia influences the splashing formation through a Kelvin–Helmholtz-like instability of the surface of the impacting droplet, in agreement with former theoretical works.

scholarly journals Large-scale fragmentation of gas cloud rotating at the Galactic center

1991 ◽  
Vol 147 ◽  
pp. 215-217
Author(s):  
M. Fujimoto ◽  
Y. Tatematsu
Keyword(s):  
Gravitational Potential ◽  
Large Scale ◽  
Galactic Center ◽  
Major Axis ◽  
Matter Density ◽  
The Self ◽  
Dynamical Structure ◽  
Gas Density ◽  
Self Gravity ◽  
Gas Cloud

A rotating and slowly-contracting gas cloud is followed in the deep gravitational potential of the galactic center. When the gas density increases as high as (102 — 103)H2 cm—3, which is more than twenty times as large as the background matter density, the self-gravity of the cloud becomes dominant to govern its dynamical structure. The cloud elongates and then splits into two separated objects, as observed at the centers of IC342, NGC6946, and Maffei 2 where we have two symmetric peaks on the major axis of the 12CO (J=1-0) cloud.

scholarly journals Cosmic rays and magnetic fields in the core and halo of the starburst M82: implications for galactic wind physics

2020 ◽  
Vol 494 (2) ◽  
pp. 2679-2705 ◽  
Author(s):  
Benjamin J Buckman ◽  
Tim Linden ◽  
Todd A Thompson
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Radio Emission ◽  
Large Scale ◽  
Gamma Ray ◽  
Minor Axis ◽  
Physical Parameters ◽  
Gas Density ◽  
Star Forming

ABSTRACT Cosmic rays (CRs) and magnetic fields may be dynamically important in driving large-scale galactic outflows from rapidly star-forming galaxies. We construct two-dimensional axisymmetric models of the local starburst and superwind galaxy M82 using the CR propagation code galprop. Using prescribed gas density and magnetic field distributions, wind profiles, CR injection rates, and stellar radiation fields, we simultaneously fit both the integrated gamma-ray emission and the spatially resolved multifrequency radio emission extended along M82’s minor axis. We explore the resulting constraints on the gas density, magnetic field strength, CR energy density, and the assumed CR advection profile. In accord with earlier one-zone studies, we generically find low central CR pressures, strong secondary electron/positron production, and an important role for relativistic bremsstrahlung losses in shaping the synchrotron spectrum. We find that the relatively low central CR density produces CR pressure gradients that are weak compared to gravity, strongly limiting the role of CRs in driving M82’s fast and mass-loaded galactic outflow. Our models require strong magnetic fields and advection speeds of the order of ∼1000 km s−1 on kpc scales along the minor axis in order to reproduce the extended radio emission. Degeneracies between the controlling physical parameters of the model and caveats to these findings are discussed.

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