scholarly journals Real gas state equations comparative analysis for low-temperature calculations

2019 ◽  
Vol 140 ◽  
pp. 05007 ◽  
Author(s):  
Mikhail Sokolov ◽  
Nikolay Sadovsky ◽  
Anatoly Zuev ◽  
Lyubov Gileva ◽  
Minh Hai Nguyen
Keyword(s):  
Comparative Analysis ◽  
Low Temperature ◽  
Exact Equation ◽  
Gas Temperature ◽  
State Equations ◽  
Two Phase ◽  
Accurate Identification ◽  
Real Gas ◽  
Mass Transfer Processes ◽  
Definition Of

In this paper, various real gas state equations are considered and their comparative analysis is carried out. The following state equations are studied in the work: Benedict-Webb-Rubin modification equation, Ridlich-Kwong Real Gas equation, Peng-Robinson Real Gas equation, and the modified Ridlich-Kwong real gas state equations proposed by Barsuk S.D. We have made a direct comparison of these calculation methods with most accurate identification. In addition, the paper analyzes the equations features, with applicability limits definition of each state equations. For the chosen one, as the most universal and exact equation, the calculations were made for the liquid phase and the real gas two-phase state. Based on the data obtained, polynomials were developed for various parameters depending on the gas temperature, which can later be used to build various mathematical models. Our conclusions show main advantages of selected equation for real gases and the reasons for choosing it for modeling low-temperature heat and mass transfer processes.

scholarly journals Investigation of humid air physical properties influence on the heat and mass transfer processes calculation accuracy

Vestnik IGEU ◽  
2020 ◽  
pp. 5-13
Author(s):  
M.V. Kozlova ◽  
P.S. Sokolov ◽  
A.V. Bannikov
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Physical Properties ◽  
Heat And Mass Transfer ◽  
Ideal Gas ◽  
State Equations ◽  
Humid Air ◽  
Real Gas ◽  
Transfer Processes ◽  
Mass Transfer Processes

Humid air is a mixture of dry air and water vapor and is widely used in various power and technical devices. Most theoretical studies of the properties of humid air are based on Mendeleev-Clapeyron ideal gas equa-tion, which doesn’t take into account the association, intermolecular interaction, and particularities of the thermodynamic behavior of humid air as a mixture of gases. The use of this equation leads to inaccuracy in determining the parameters of the state of humid air, which can reach up to 55 %. Therefore, the issues con-cerning the actual properties of humid air determining remain poorly understood. The ideal gas model is based on Mendeleev-Clapeyron equation. To study the actual parameters of the humid air state and its properties, Vukalovich-Novikov’s and Molie’s real gas state equations have been used.Several equations of the state of real gas, taking into account the interaction of water vapor molecules have been considered. The actual physical properties of humid air are determined, and their influence on the coupled heat and mass transfer processes for various conditions is evaluated. The actual values of the thermophysical properties of humid air have been derived. The thermodynamic limits for humid air have been determined using Mendeleev-Clapeyron’s, Vukalovich-Novikov’s and Molie’s state equations. It has been proved Vukalovich-Novikov’s state equation to be the best to represent the quantitative relations between the pressure, specific volume, and the temperature of saturated water vapor. Its application reduces the error of calculations by 39–50 %. The results obtained allow to improve the accuracy of calculating heat and mass transfer when designing contact heat exchangers, convective drying units and hygroscopic desalination plants, compression processes with water or water vapor injection, as well as the processes of mixing flue gases with water vapor in the combustion chambers of gas-steam installations.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

A Comparison of Tem and Apfim to the Interpretation of Modulated Microstructures

1985 ◽  
Vol 43 ◽  
pp. 70-71
Author(s):  
M.G. Burke ◽  
M.K. Miller
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Superlattice Reflection ◽  
High Volume ◽  
Atom Probe ◽  
Dark Field ◽  
Miscibility Gap ◽  
Second Phase ◽  
Two Phase ◽  
Probe Field

Interpretation of fine-scale microstructures containing high volume fractions of second phase is complex. In particular, microstructures developed through decomposition within low temperature miscibility gaps may be extremely fine. This paper compares the morphological interpretations of such complex microstructures by the high-resolution techniques of TEM and atom probe field-ion microscopy (APFIM).The Fe-25 at% Be alloy selected for this study was aged within the low temperature miscibility gap to form a <100> aligned two-phase microstructure. This triaxially modulated microstructure is composed of an Fe-rich ferrite phase and a B2-ordered Be-enriched phase. The microstructural characterization through conventional bright-field TEM is inadequate because of the many contributions to image contrast. The ordering reaction which accompanies spinodal decomposition in this alloy permits simplification of the image by the use of the centered dark field technique to image just one phase. A CDF image formed with a B2 superlattice reflection is shown in fig. 1. In this CDF micrograph, the the B2-ordered Be-enriched phase appears as bright regions in the darkly-imaging ferrite. By examining the specimen in a [001] orientation, the <100> nature of the modulations is evident.

Engagement as a Reflection of Communicative Potential

Communicology ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 27-33
Author(s):  
N.V. Kirillina
Keyword(s):  
Comparative Analysis ◽  
Interdisciplinary Research ◽  
Strategic Communication ◽  
Phenomenological Tradition ◽  
The Social ◽  
Social Potential ◽  
Definition Of ◽  
Communicative Processes

The paper represents the analysis of the concept of communicative. The choice of topic is determined by the search for criteria and tools for assessing the results of strategic communication, taking into account the development of its interactive forms. The author leads the existing approaches to the definition of the concept of engagement and identifies the areas for further interdisciplinary research of the specified subject, and raises the issue of the appropriateness of using the engagement indicators in the assessment the social potential of communication. The work is based on the phenomenological tradition in the interpretation of communicative processes and the metamodel of communication of R. Craig. The author uses the methods of comparative analysis, analogy, generalization, and combined methodology of interdisciplinary analysis.

Investigation of two-dimensional nonstationary processes of outflow a gas-saturated liquid from axisymmetric vessels

2012 ◽  
Vol 9 (1) ◽  
pp. 47-52
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Buzina
Keyword(s):  
Comparative Analysis ◽  
Numerical Model ◽  
Liquid Mixture ◽  
Phase Model ◽  
Test Problems ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Saturated Liquid ◽  
Two Phase ◽  
One Dimensional

The two-dimensional and two-phase model of the gas-liquid mixture is constructed. The validity of numerical model realization is justified by using a comparative analysis of test problems solution with one-dimensional calculations. The regularities of gas-saturated liquid outflow from axisymmetric vessels for different geometries are established.

scholarly journals Validation of Sexological Worldview

SAGE Open ◽  
2012 ◽  
Vol 2 (1) ◽  
pp. 215824401243907 ◽  
Author(s):  
Justin A. Sitron ◽  
Donald A. Dyson
Keyword(s):  
Attitude Change ◽  
Service Provision ◽  
Perspective Transformation ◽  
The United States ◽  
Qualitative Approach ◽  
Second Phase ◽  
Two Phase ◽  
Convenience Sample ◽  
Developmental Characteristics ◽  
Definition Of

The authors originally posited that a new construct must be developed to measure the success of affective training for sexologists, particularly the Sexuality Attitudes Reassessment (SAR) modality. Couching their critique in studies that have been conducted to measure the SAR’s effectiveness as a method used to evoke perspective transformation and more sensitive and humanistic service provision, the authors argued that the development of a professional’s sexological worldview would be a more accurate construct than attitude change to measure when considering the outcomes of SAR training. This study in the United States used a two-phase qualitative approach to validate the proposed sexological worldview construct. In the first phase, they surveyed a panel of 16 sexologists regarding their original proposed definition of sexological worldview and refined it. In the second phase, they completed 30 one-on-one interviews with a convenience sample of sexologists and sexology students. Using an inductive content analysis of the interview transcripts, seven themes emerged in support of the proposed definition of sexological worldview, including its components and its developmental characteristics. The article concludes with a discussion of the implications for the use of the construct for the training of sexologists.

Dissociation and Subsidence of Hydrated Sediment: Coupled Models

2009 ◽  
Vol 27 (2) ◽  
pp. 105-131 ◽  
Author(s):  
Mohamed Iqbal Pallipurath
Keyword(s):  
Thermal Dissociation ◽  
Hydrate Formation ◽  
Coupled Models ◽  
Two Phase ◽  
Strength Deterioration ◽  
Intrinsic Kinetics ◽  
Radial Heat Flow ◽  
Radial Heat ◽  
Definition Of ◽  
Pressure Changes

Thermal dissociation of hydrated sediment by a pumped hot fluid is modeled. A radial heat flow from the hot pipe is assumed. The coordinate system is cylindrical. Three components (hydrate, methane and water) and three phases (hydrate, gas, and aqueous-phase) are considered in the simulator. The intrinsic kinetics of hydrate formation or dissociation is considered using the Kim-Bishnoi model. Mass transport, including two-phase flow, molecular diffusions and heat transfer involved in formation or dissociation of hydrates are included in the governing equations, which are discretized with finite volume difference method and are solved in an explicit manner. The strength deterioration of the hydrate bed as a result of dissociation is investigated with a geo-mechanical model. The way in which dissociation affects the bed strength is determined by plugging in the porosity and saturation change as a result of dissociation into the sediment collapse equations. A mechanism to measure the pore pressure changes occurring due to dissociation is developed. The rate of collapse as dissociation proceeds is determined and the model thus enables the definition of a safety envelope for gas hydrate drilling.

scholarly journals Macroscopic degeneracy and order in the 3D plaquette Ising model

2015 ◽  
Vol 29 (20) ◽  
pp. 1550109 ◽  
Author(s):  
Desmond A. Johnston ◽  
Marco Mueller ◽  
Wolfhard Janke
Keyword(s):  
Low Temperature ◽  
Magnetic Order ◽  
Finite Size ◽  
Temperature Phase ◽  
Finite Size Scaling ◽  
First Order ◽  
Magnetic Order Parameter ◽  
First Order Transition ◽  
Definition Of ◽  
Low Temperature Phase

The purely plaquette 3D Ising Hamiltonian with the spins living at the vertices of a cubic lattice displays several interesting features. The symmetries of the model lead to a macroscopic degeneracy of the low-temperature phase and prevent the definition of a standard magnetic order parameter. Consideration of the strongly anisotropic limit of the model suggests that a layered, “fuki-nuke” order still exists and we confirm this with multi-canonical simulations. The macroscopic degeneracy of the low-temperature phase also changes the finite-size scaling corrections at the first-order transition in the model and we see this must be taken into account when analyzing our measurements.

The Effect of Turbulence and Real Gas Models on the Two Phase Spontaneously Condensing Flows in Nozzle

2013 ◽  
Author(s):  
Yogini Patel ◽  
Giteshkumar Patel ◽  
Teemu Turunen-Saaresti
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Navier Stokes ◽  
Two Phase ◽  
Real Gas ◽  
Spontaneous Condensation ◽  
Condensing Flows ◽  
Computational Fluid Dynamics Cfd

The aim of the paper is to analyse the effect of turbulence and real gas models on the process of spontaneous condensation in converging diverging (CD) nozzle by using commercial Computational Fluid Dynamics (CFD) code. The calculations were based on the 2-D compressible Navier-Stokes (NS) equations coupled with two-equation turbulence model, and the non-equilibrium spontaneous condensing steam flow was solved on the basis of the classical nucleation theory. The results were validated to the available experimental data.

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