A Simplified Approach for Predicting the Intermittent Behavior of Gas-Liquid Mixtures in Pipes

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
M. Fossa ◽  
A. Marchitto
Keyword(s):  
Experimental Data ◽  
Void Fraction ◽  
Computing Time ◽  
Liquid Mixtures ◽  
New Approach ◽  
Pressure Drops ◽  
Simplified Approach ◽  
Intermittent Behavior ◽  
Flow Parameters ◽  
Simplified Procedure

A new approach to the classical slug flow model is here proposed based on an original correlation for the minimum liquid level in the stratified regions of intermittent horizontal flows. This correlation is obtained by fitting experimental data obtained from a statistical analysis of void fraction signals from ring impedance probes. The new procedure improves the original model in terms of computing time reduction and algorithm simplification. In addition, it is demonstrated that the new closure relationship can be derived with more consistent experimental results, with respect to the slug length, which is employed in the original approach. The predictions of the main flow parameters are presented with reference to the classical and new approach, and all the results are critically compared with literature experimental data. It is demonstrated that the simplified procedure is able to predict the pressure drops and average void fraction values in good agreement with experimental measurements, while only the slug frequency and slug length predictions are affected by poor reliability.

scholarly journals A simplified approach to kinematics of stars in solar neighbourhood

2015 ◽  
pp. 75-80
Author(s):  
M. Stojanovic
Keyword(s):  
Satisfactory Agreement ◽  
Gravitational Potential ◽  
Milky Way ◽  
Computing Time ◽  
Three Dimensional ◽  
Thin Disk ◽  
Solar Neighbourhood ◽  
Galactic Centre ◽  
Simplified Approach ◽  
Simplified Procedure

For a number of stars from the Solar neighbourhood the eccentricities of their galactocentric orbits are calculated by using a simplified procedure given by Ninkovic (2011). Eccentricities are calculated from the three-dimensional orbits around the centre of the Milky Way for the same sample of stars, by applying a model with the analytically given gravitational potential as well. The orbital eccentricities (radial span of each star) obtained in these two manners show a satisfactory agreement. It can be concluded that for typical thin-disk stars the use of such a simplified procedure, which requires much less computing time per star, in determining their motion around the Galactic centre is justified.

Theoretical Interpretation of High-Performance Chromatographic Data for a Heterogeneous Series of Compounds

1992 ◽  
Vol 57 (1) ◽  
pp. 33-45
Author(s):  
Vladimír Jakuš
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Theoretical Interpretation ◽  
Retention Data ◽  
Theoretical Evaluation ◽  
New Approach ◽  
Free Energy Of Solvation ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Reversed Phases

A new approach to theoretical evaluation of the Gibbs free energy of solvation was applied for estimation of retention data in high-performance liquid chromatography on reversed phases (RP-HPLC). Simple and improved models of stationary and mobile phases in RP-HPLC were employed. Statistically significant correlations between the calculated and experimental data were obtained for a heterogeneous series of twelve compounds.

Excess molar volumes and viscosities of binary mixtures of some polyethers with propylamine at 298.15 K

2002 ◽  
Vol 80 (5) ◽  
pp. 467-475 ◽  
Author(s):  
Amalendu Pal ◽  
Rakesh Kumar Bhardwaj
Keyword(s):  
Experimental Data ◽  
Viscous Flow ◽  
Binary Mixtures ◽  
Entire Range ◽  
Excess Volume ◽  
Excess Molar Volumes ◽  
Liquid Mixtures ◽  
Molar Volumes ◽  
Binary Liquid ◽  
Volume Viscosity

Excess molar volumes (VmE) and dynamic viscosities (η) have been measured as a function of composition for binary liquid mixtures of propylamine with 2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, 3,6,9-trioxaundecane, and 5,8,11-trioxapentadecane at 298.15 K. The excess volumes are positive over the entire range of composition for the systems propylamine + 2,5-dioxahexane, and + 3,6,9-trioxaundecane, negative for the systems propylamine + 2,5,8,11-tetraoxadodecane, and + 5,8,11-trioxapentadecane, and change sign from positive to negative for the remaining system propylamine + 2,5,8-trioxanonane. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG*E) have been derived. These values are positive for all mixtures with the exception of propylamine + 2,5-dioxahexane.Key words : excess volume, viscosity, binary mixtures.

scholarly journals DYNAMICS OF TWO-PHASE FLOW ACROSS HORIZONTAL TUBE BUNDLES - A REVIEW

2005 ◽  
Vol 4 (2) ◽  
Author(s):  
G. Ribatskia ◽  
J. R. Thome
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Experimental Studies ◽  
Horizontal Tube ◽  
Prediction Methods ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Frictional Pressure Drop ◽  
Tube Bundles

This paper presents a state-of-the-art review of the hydrodynamic aspects of two-phase flow across horizontal tube bundles. The review covers studies related to the evaluation of void fraction, two-phase flow behaviors and pressure drops on the shell side of staggered and in-line tube bundles for upward, downward and side-to-side flows. This study of the literature critically describes the proposed flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop. These predicting methods are generally based on experimental results for adiabatic air-water flows. A limited number of experimental studies with R-11 and R-113 were also carried out in the past. The review shows noticeable discrepancies among the available prediction methods. Finally, this study suggests that further research focusing on the development of representative databanks and new prediction methods is still necessary.

Effects of Attack Angle and Relative Thickness of Novel Wing-Shaped Turbulators on Turbulent Hydrothermal Performance in a Two-Pass Square Channel

2021 ◽  
pp. 1-7
Author(s):  
Tong-Miin Liou ◽  
Chieh Chu Chen ◽  
Chun-Sheng Wang
Keyword(s):  
Nusselt Number ◽  
Fused Deposition Modeling ◽  
Transverse Velocity ◽  
Attack Angle ◽  
Ir Camera ◽  
Pressure Drops ◽  
Square Channel ◽  
Fused Deposition ◽  
Flow Parameters ◽  
Number Ratio

Abstract This work aims to combine the effects of the near wall and core flow disturbance by proposing novel wing-shaped turbulators. The new turbulators are fabricated with the fused deposition modeling (3D printing) technology. To explore their effects on detailed flow fields, local temperature distributions, and pressure drops in a two-pass square channel, Particle Image Velocimetry (PIV), Infrared Thermography (IR camera), and pressure transducer measurements are performed. The turbulator pitch, clearance, and truncation gap ratio based on the channel hydraulic diameter of 45.5 mm are respectively fixed at 0.7, 0.25 and 0.06. Varied parameters include turbulator attack angle (α = 10°, 15°, 20°, and 30°), maximum thickness to chord line ratio (t/C = 0.08, 0.13, 0.16, 0.20, and 0.23), and bulk Reynolds number (Re = 5,000-20,000). From the experimental results and flow parameters analyzed, the dimensionless spanwise-averaged mean transverse velocity and cross-sectionally averaged vorticity magnitude are identified to be the most relevant ones to spanwise-averaged local Nusselt number ratio in the first and second pass. Among all examined cases and previous data with Fanning friction factor ratio (f¯/fo) less than 50, the case with α = 20° and t/C = 0.20 attains the highest thermal performance factor and overall Nusselt number ratio (Nu¯/Nuo) up to 1.68 and 5.36, respectively. Furthermore, empirical correlations of Nu¯/Nuo and f¯/fo versus α, t/C, and Re are proposed.

Effects of Attack Angle and Relative Thickness of Novel Wing-Shaped Turbulators on Turbulent Hydrothermal Performance in a Two-Pass Square Channel

2020 ◽  
Author(s):  
Tong-Miin Liou ◽  
Chieh-Chu Chen ◽  
Chun-Sheng Wang
Keyword(s):  
Nusselt Number ◽  
Fused Deposition Modeling ◽  
Transverse Velocity ◽  
Attack Angle ◽  
Ir Camera ◽  
Pressure Drops ◽  
Square Channel ◽  
Fused Deposition ◽  
Flow Parameters ◽  
Number Ratio

Abstract This work aims to combine the effects of the near wall and core flow disturbance by proposing novel wing-shaped tabulators. The new tabulators are fabricated with the fused deposition modeling (3D printing) technology. To explore their effects on detailed flow fields, local temperature distributions, and pressure drops in a two-pass square channel, Particle Image Velocimetry (PIV), Infrared Thermography (IR camera), and pressure transducer measurements are performed. The tabulator pitch, clearance, and truncation gap ratio based on the channel hydraulic diameter of 45.5 mm are respectively fixed at 0.7, 0.25 and 0.06. Varied parameters include tabulator attack angle (α = 10°, 15°, 20°, and 30°), maximum thickness to chord line ratio (t/C = 0.08, 0.13, 0.16, 0.20, and 0.23), and bulk Reynolds number (Re = 5,000–20,000). From the experimental results and flow parameters analyzed, the dimensionless spanwise-averaged mean transverse velocity and cross-sectionally averaged vorticity magnitude are identified to be the most relevant ones to spanwise-averaged local Nusselt number ratio in the first and second pass. Among all examined cases and previous data with Fanning friction factor ratio (f¯/fo) less than 50, the case with α = 20° and t/C = 0.20 attains the highest thermal performance factor and overall Nusselt number ratio (Nu¯/Nuo) up to 1.68 and 5.36, respectively. Furthermore, empirical correlations of Nu¯/Nuo and f¯/fo versus α, t/C, and Re are proposed.

A New Modeling Approach to Reacting Dispersed Flow in Smelting Cyclones

2000 ◽  
Author(s):  
M. Modigell ◽  
M. Weng
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Gas Flow ◽  
Equilibrium Calculation ◽  
New Approach ◽  
Reaction Progress ◽  
Numeric Simulation ◽  
Thermodynamic Equilibrium Calculation ◽  
Simulation Results ◽  
Comparison With Experimental Data

Abstract The present paper proposes a new approach to analyse the conversion of complexly composed particles that are dispersed in a cyclone gas flow at high temperatures. The numeric simulation of flow field and particle trajectories is coupled with a thermodynamic equilibrium calculation which describes the particle reaction progress. First simulation results and the comparison with experimental data are shown in this paper.

Numerical Method of Estimating Distance Between Wells

2021 ◽  
Author(s):  
Ayobami Ezekiel ◽  
Prince Oduh ◽  
Emmanuel Okoh ◽  
Collins Onah ◽  
Michael Ojah ◽  
...  
Keyword(s):  
Integral Equation ◽  
Pressure Drop ◽  
Polynomial Equation ◽  
Important Variable ◽  
Well Testing ◽  
Model Calculations ◽  
New Approach ◽  
Pressure Drops ◽  
Quantum Leap ◽  
Interference Test

Abstract In this study, a simpler numerical model for calculating inter-well distance was developed. This model was developed as an alternative to the Ei-function used for computing pressure drops. The mainobjective of developing this model is tomake resolution of pilfering issues easyto resolve. With the developed model, calculations relating to pressure drops and more specifically, inter-well distance, can be done with greater ease and accuracy. In developing this model, the integral equation of the Eifunction in the pressure drop equation was solved numerically. The numerical solution reduced thepressure drop equation to a polynomial equation which is much easier to solve. The developed model was used to solve real problems. Results generated from it were compared with those obtained using previous approaches. Important informationsuch as well configuration, region of the reservoir, and transient history wherethe work is valid are stated. The development of the correlations and tables forthe range of validity and values of the Ei-function is a major quantum leap in well testing and analysis. It will be quite cumbersome to resolve integrals with unknowns, hence, methods of trials and errors have been resorted to over the years. However, this new approach resolved the pressure drop equation into a systemof polynomials which is much easier to solve. Consequently, the distance betweenpossibly interfering wells (which is an important variable during interference test) can now be gotten with ease. The developed model is valid within the range of validity of the Ei-function. Without doubt, this work will help redefine the pressure drop equation into a polynomial equation which can easily be resolved using any of the known approaches to solving problems involving polynomials. More so, getting the correct distance betweenthe two wells in question is pivotal to the test. With the model developed in this work, getting inter-well distance is now easier and more accurate.

Neat ionic liquids versus ionic liquid mixtures: a combination of experimental data and molecular simulation

2019 ◽  
Vol 21 (42) ◽  
pp. 23305-23309 ◽  
Author(s):  
Andreia S. L. Gouveia ◽  
Carlos E. S. Bernardes ◽  
Elena I. Lozinskaya ◽  
Alexander S. Shaplov ◽  
José N. Canongia Lopes ◽  
...  
Keyword(s):  
Experimental Data ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Molecular Simulation ◽  
Liquid Mixtures

Simple mixtures of ionic liquids (IL–IL mixtures) can become a promising approach for the substitution of task-specific ILs.

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