scholarly journals Modeling of Hydrodynamics in a 25 mm ϕ Pulsed Disk and Doughnut Column

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Rajnish Kumar ◽  
D. Sivakumar ◽  
Shekhar Kumar ◽  
U. Kamachi Mudali
Keyword(s):  
Slip Velocity ◽  
Drop Size ◽  
Absolute Error ◽  
Model Parameters ◽  
Dispersed Phase ◽  
Acid System ◽  
Hydrodynamic Parameters ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

The hydrodynamic parameters, namely, dispersed phase holdup and flooding throughput, have been investigated in 25 mm diameter pulsed disk and doughnut column (PDDC), in no mass transfer conditions. In this work, using existing correlations on plate pulsed columns, the dispersed phase holdup and the flooding throughput are empirically modelled well using the slip velocity concept. A good agreement is observed between experimental values and predicted values obtained from empirical correlation. The experimental data for dispersed phase holdup and flooding throughput has been modelled using the Van Delden model to describe the hydrodynamics characteristics of a PDDC and necessary adjustable parameters for drop size distribution and dispersed phase holdup are updated for 30% TBP-nitric acid system. The model parameters were estimated by minimizing the absolute error between experimental and theoretical values of flooding throughput and holdup data. It was found that the measured values and observed trends could be described accurately using this model after fitting holdup and flooding data. The error between the experimental and theoretical values of flooding throughput and holdup was found to be less than 10%.

Slip velocity and hydrodynamic parameters in liquid-liquid spray columns

1989 ◽  
Vol 54 (4) ◽  
pp. 990-995
Author(s):  
Milan Sovilj
Keyword(s):  
Reynolds Number ◽  
Interfacial Tension ◽  
Slip Velocity ◽  
Dispersed Phase ◽  
Dimensionless Group ◽  
Hydrodynamic Parameters ◽  
Wide Range ◽  
Liquid Spray ◽  
Predicted Values ◽  
Good Agreement

An empirical correlation for the prediction of slip velocity in liquid-liquid spray columns, which includes a dimensionless group containing the interfacial tension, is presented. Good agreement between experimental and predicted values of slip velocity is obtained over a wide range of dispersed phase hold-up (0.97–36.2%) and Reynolds number (58-1067).

Tests of second-generation and third-generation density functionals for electron affinities of the alkylthio radicals

2014 ◽  
Vol 13 (04) ◽  
pp. 1450030 ◽  
Author(s):  
Aifang Gao ◽  
Aiguo Li
Keyword(s):  
Dft Method ◽  
Absolute Error ◽  
Molecular Structures ◽  
Basis Set ◽  
Density Functionals ◽  
Electron Affinities ◽  
Generalized Gradient ◽  
Experimental Values ◽  
P Type ◽  
Good Agreement

The molecular structures and electron affinities of the R – S / R – S -( R = CH 3, C 2 H 5, n- C 3 H 7, n- C 4 H 9, n- C 5 H 11, i- C 3 H 7, i- C 4 H 9, t- C 4 H 9) species have been studied using 17 pure and hybrid density functionals (five generalized gradient approximation (GGA) methods, six hybrid GGAs, one meta GGA method and five hybrid meta GGAs). The basis set used in this work is of double-ζ plus polarization quality with additional diffuse s- and p-type functions, denoted by DZP++. The geometries are fully optimized with each DFT method and discussed. Harmonic vibrational frequencies are found to be within 3.5% of available experimental values for most functionals. Three different types of the neutral-anion energy separations have been presented. The theoretical electron affinities of alkylthio radicals are in good agreement with the experiment data. The M06 method is very good for the adiabatic electron affinity calculations, and the average absolute error is 0.0439 eV. The HCTH method performs better for EA prediction. The M06-HF, mPWPW91, VSXC and B98 are also reasonable. The most reliable adiabatic electron affinities are predicted to be 1.864 eV ( CH 3 S ), 1.946 eV ( C 2 H 5 S ), 1.959 eV (n- C 3 H 7 S ), 1.970 eV (n- C 4 H 9 S ), 1.982 eV (n- C 5 H 11 S ), 2.053 eV (i- C 3 H 7 S ), 1.991 eV (i- C 4 H 9 S ) and 2.100 eV (t- C 4 H 9 S ) at the M06/DZP++ level of theory, respectively.

scholarly journals Effects of Parameters on Solvent Extraction of Oil From Sandbox (Hura Crepitans) Seed Oil Using 2^4 Factorial Design

2021 ◽  
Vol 15 ◽  
pp. 48-55
Author(s):  
Owhor Sampson Chisa ◽  
J. D. Amine ◽  
Abdul Gambo Alim ◽  
Luka Bobby Shakarau ◽  
Isaiah Kehinde Ogbobame ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Seed Oil ◽  
Hydraulic Press ◽  
Biodiesel Production ◽  
Extraction Temperature ◽  
Physiochemical Properties ◽  
Hura Crepitans ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

The present work deals with the production of biodiesel from Sandbox (Hura crepitans) seed oil and the optimization of the parameters that influence the transesterification of Sandbox (Hura crepitans)seed oil into biodiesel using Response Surface Methodology. Hura crepitans oil was obtained from by using hydraulic press for Mechanical and n-hexane for solvent extraction. Esterification was done using methanol and sodium hydroxide. A total of 48 experiments using Central Composite Design were carried out. The R-Squared, Adequate Precision, Predicted and Adjusted R-Squared values were 0.9367, 19.219, 0.8576 and 0.9070 respectively. The result of the extraction of oil, physiochemical properties, and optimization process shows that sandbox (Hura crepitans) seed oil has characteristics that are more favorable to biodiesel production. The optimal conditions for extraction of oil from sandbox seed oil were given as alcohol/ oil ratio of 5.0, catalyst amount of 20 g/ml, extraction temperature of 60 ºC, and extraction time of 45.01 minutes, with the predicted oil yield as 97.33% respectively which shows that the experimental values are in good agreement with predicted values.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

scholarly journals Estimation of Activity Interaction Parameters in Fe-S-j Systems

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 808 ◽  
Author(s):  
Tianhua Ju ◽  
Xueyong Ding ◽  
Yingyi Zhang ◽  
Weiliang Chen ◽  
Xiangkui Cheng ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Excess Entropy ◽  
Geometric Model ◽  
Calculation Model ◽  
Interaction Parameters ◽  
Mixing Enthalpy ◽  
Predicted Values ◽  
Experimental Values ◽  
Activity Interaction Parameter ◽  
Good Agreement

It is important to know the activity interaction parameters between components in melts in the process of metallurgy. However, it’s considerably difficult to measure them experimentally, relying still to a large extent on theoretical calculations. In this paper, the first-order activity interaction parameter (esj) of j on sulphur in Fe-based melts at 1873 K is investigated by a calculation model established by combining the Miedema model and Toop-Hillert geometric model as well as considering excess entropy and mixing enthalpy. We consider two strategies, with or without using excess entropy in the calculations. Our results show that: (1) the predicted values are in good agreement with those recommended by Japan Society for Promotion of Science (JSPS); and (2) the agreement is even better when excess entropy is considered in the calculations. In addition, the deviations of our theoretical results from experimental values eS(exp)j-eS(cal)j depend on the element j’s locations in the periodic table.

Weak Extinction Limits of Turbulent Heterogeneous Fuel/Air Mixtures

1980 ◽  
Vol 102 (2) ◽  
pp. 416-421 ◽  
Author(s):  
D. R. Ballal ◽  
A. H. Lefebvre
Keyword(s):  
Liquid Fuel ◽  
Drop Size ◽  
Air Pressure ◽  
Theoretical Studies ◽  
Turbulence Level ◽  
Test Program ◽  
Stabilized Flames ◽  
Experimental Values ◽  
Experimental And Theoretical Studies ◽  
Good Agreement

Experimental and theoretical studies are made of the factors governing the weak extinction limits of stabilized flames supplied with flowing mixtures of liquid fuel drops and air. The test program includes wide variations in inlet air pressure, velocity and turbulence level, and also covers wide ranges of fuel volatility and mean drop size. The influence of flameholder size and blockage is also examined. An equation is derived for predicting weak extinction limits which shows good agreement with the corresponding experimental values.

scholarly journals Weak Extinction Limits of Turbulent Heterogeneous Fuel/Air Mixtures

1979 ◽  
Author(s):  
D. R. Ballal ◽  
A. H. Lefebvre
Keyword(s):  
Liquid Fuel ◽  
Drop Size ◽  
Air Pressure ◽  
Theoretical Studies ◽  
Turbulence Level ◽  
Test Program ◽  
Stabilized Flames ◽  
Experimental Values ◽  
Experimental And Theoretical Studies ◽  
Good Agreement

Experimental and theoretical studies are made of the factors governing the weak extinction limits of stabilized flames supplied with flowing mixtures of liquid fuel drops and air. The test program includes wide variations in inlet air pressure, velocity and turbulence level, and also covers wide ranges of fuel volatility and mean drop size. The influence of flameholder size and blockage is also examined. An equation is derived for predicting weak extinction limits which shows good agreement with the corresponding experimental values.

Isobaric Vapor-Liquid Equilibria for the System Containing Acetic Acid at 101.3kPa

2012 ◽  
Vol 560-561 ◽  
pp. 79-85 ◽  
Author(s):  
Hua Xin ◽  
Xu Feng Wang ◽  
Joshua Qing Song Li
Keyword(s):  
Acetic Acid ◽  
Vapor Phase ◽  
Binary Data ◽  
Model Parameters ◽  
Nrtl Model ◽  
Vle Data ◽  
Predicted Values ◽  
Experimental Values ◽  
Vapor Liquid Equilibria ◽  
Vapor Liquid

Isobaric vapor-liquid equilibria (VLE) data for water + acetic acid, acetic acid + n-pentyl acetate, water + acetic acid + n-pentyl acetate systems have been measured at 101.33 k Pa using a recirculating still. The nonideality of the vapor phase caused by the association of the acetic acid has been corrected by the Hayden-O’Connellmethod. The three experimental binary data have been correlated by the NRTL and UNIQUAC models. The obtained NRTL model parameters from binary data have been used to predict ternary VLE data. The ternary predicted values obtained in this way agree well with the experimental values.

An Analytical Examination of the Combustion of a Turbulent Jet in an Environment of Air Containing a Premixed Fuel or a Diluent

1995 ◽  
Vol 117 (3) ◽  
pp. 234-238 ◽  
Author(s):  
P. Wierzba ◽  
G. A. Karim ◽  
I. Wierzba
Keyword(s):  
Flame Length ◽  
Turbulent Jet ◽  
Simple Analytical Model ◽  
Flammability Limits ◽  
Gaseous Fuels ◽  
Gaseous Environment ◽  
Fuel Jet ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

A simple analytical model for the mixing and combustion of an axisymmetric turbulent gaseous fuel jet discharging into a co-flowing streaming gaseous environment of an auxiliary fuel and/or a diluent homogeneously mixed with air is presented. A number of gaseous fuels and diluents are considered. It is shown that the combustion characteristics of a fuel jet can be modified significantly by the presence of a relatively small amount of a fuel in the surrounding air at concentrations well below the corresponding local flammability limits. Correlative procedures are presented for estimating changes in the flame length, the size of the combustion zone, and the blowout limits with changes in the type and concentration of the fuel in the surroundings. Predicted values showed generally good agreement with the corresponding experimental values.

On the macroscopic modelling of dilute emulsions under flow

2017 ◽  
Vol 831 ◽  
pp. 433-473 ◽  
Author(s):  
Paul M. Mwasame ◽  
Norman J. Wagner ◽  
Antony N. Beris
Keyword(s):  
Newtonian Fluid ◽  
Macroscopic Model ◽  
Colloid Interface ◽  
Model Parameters ◽  
Dispersed Phase ◽  
Emulsion Model ◽  
Conformation Tensor ◽  
Droplet Morphology ◽  
Extra Stress ◽  
Good Agreement

A new macroscopic model describing the rheology and microstructure of dilute emulsions with droplet morphology is developed based on an internal contravariant conformation tensor variable which is physically identified with the deformed ellipsoidal geometry of the dispersed phase. The model is consistent with existing first-order capillary number, $O(Ca)$, theory describing the microstructure as well as $O(Ca^{2})$ theory describing the emulsion-contributed extra stress. These asymptotic solutions are also used to determine all of the model parameters, making it the only macroscopic emulsion model that is consistent with all available asymptotic theories in the limit of small $Ca$. The governing equations are obtained from the Poisson and dissipation brackets, as developed for an incompressible fluid system endowed with an internal contravariant second-order tensor, subject to the imposition of the constraint of a unit determinant. First proposed by Maffettone & Minale (J. Non-Newtonian Fluid Mech., vol. 78, 1998, pp. 227–241), this constraint physically corresponds to conservation of the volume of the dispersed phase in the emulsion. The Hamiltonian of the emulsion is expressed through the surface energy of the dispersed phase, in addition to the kinetic energy, following previous work by Grmela et al. (J. Non-Newtonian Fluid Mech., vol. 212, 2014, pp. 1–12), but employing a more accurate evaluation of the surface area in terms of the internal contravariant conformation tensor. Structural predictions of the ellipsoid droplet morphology obtained with the new model are compared with classic experiments by Torza et al. (J. Colloid Interface Sci., vol. 38, 1972, pp. 395–411), showing good agreement.

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