scholarly journals On Criticality for a Generalized Couette Flow of a Branch-Chain Thermal Reactive Third-Grade Fluid with Reynold’s Viscosity Model

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
S. O. Salawu ◽  
A. B. Disu ◽  
M. S. Dada
Keyword(s):  
Reaction Rate ◽  
Thermal Reaction ◽  
Viscosity Model ◽  
Third Grade ◽  
Heat Equations ◽  
Fluid Viscosity ◽  
Dimensionless Energy ◽  
Initiation Reaction ◽  
Branched Chain ◽  
Energy And Momentum

This research considers the third-grade liquid flow and criticality branched-chain of a thermal reaction in a Couette generalized medium with a nonlinear viscosity model. A dimensionless transformation of the system momentum and heat equations are carried out. Compared with the diffusion coefficient, the flow is stimulated by initiation reaction rate, reaction branch-chain order, non-Newtonian term, thermal Grashof number, and pressure gradient. The reactive fluid is fully exothermic with consumption of the material, and the heat exchange in the system is greater than the exchange of heat with the ambient. A semianalytical collocation weighted residual scheme is employed for the branch-chain slice bifurcation, dimensionless energy, and momentum solutions. The results show that exponential decreases in the thermal fluid viscosity can help in controlling the boundless heat produced by the Frank-Kamenetskii term and initiation reaction rate. Therefore, the results will help in stimulating positive combustion processes.

Improvement of the Expanded Fluid Viscosity Model for Crude Oils: Effects of the Plus-Fraction Characterization Method and Density

2018 ◽  
Vol 32 (2) ◽  
pp. 1624-1633 ◽  
Author(s):  
Victor B. Regueira ◽  
Verônica J. Pereira ◽  
Gloria M. N. Costa ◽  
Silvio A. B. Vieira de Melo
Keyword(s):  
Viscosity Model ◽  
Crude Oils ◽  
Fluid Viscosity ◽  
Plus Fraction

Cavitation-induced Reactions in Pure Substituted Benzenes

1972 ◽  
Vol 50 (11) ◽  
pp. 1743-1750 ◽  
Author(s):  
G. K. Diedrich ◽  
P. Kruus ◽  
L. M. Rachlis
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Cavitation Bubble ◽  
Reaction Rate ◽  
Substituted Benzenes ◽  
Thermal Reactions ◽  
Initiation Reaction ◽  
Low Temperature Pyrolysis

The formation of polymers has been observed on exposure of pure substituted benzenes to ultrasound intense enough to cause cavitation. The products have some of the characteristics of the char obtained from low temperature pyrolysis of hydrocarbons. They are difficult to dissolve, melt above 300 °C, and give a large broad e.p.r. signal. A crude correlation between bond dissociation energy and the reaction rate suggests that the initiation reaction is a thermal decomposition in a cavitation bubble. The phenomenon is compared to radiolysis and thermal reactions.

scholarly journals Fast pyrolysis of biomass: A review of relevant aspects. Part I: Parametric study

DYNA ◽  
2015 ◽  
Vol 82 (192) ◽  
pp. 239-248 ◽  
Author(s):  
Jorge Ivan Montoya Arbeláez ◽  
Farid Chejne Janna ◽  
Manuel Garcia-Pérez
Keyword(s):  
Reaction Rate ◽  
Fast Pyrolysis ◽  
Chemical Processes ◽  
Biomass Pyrolysis ◽  
Promising Alternative ◽  
Strongly Coupled ◽  
Thermochemical Processes ◽  
Energy And Momentum ◽  
Pyrolysis Of Biomass ◽  
Physical And Chemical

Recent years have witnessed a growing interest in developing biofuels from biomass by thermochemical processes like fast pyrolysis as a promising alternative to supply ever-growing energy consumption. However, the fast pyrolysis process is complex, involving changes in phase, mass, energy, and momentum transport phenomena which are all strongly coupled with the reaction rate. Despite many studies in the area, there is no agreement in the literature regarding the reaction mechanisms. Furthermore, no detailed universally applicable phenomenological models have been proposed to describe the main physical and chemical processes occurring within a particle of biomass. This has led to difficulties in reactor design and pilot industrial scale operation, stunting the popularization of the technology. This paper reviews relevant topics to help researchers gain a better understanding of how to address the modeling of biomass pyrolysis.

New Fracturing Fluid Viscosity Model to Cure Power Law Mistakes

2020 ◽  
Author(s):  
Denis Vernigora ◽  
Stella Sypchenko ◽  
Andrey Fedorov ◽  
Olesya Olennikova
Keyword(s):  
Power Law ◽  
Viscosity Model ◽  
Fluid Viscosity ◽  
Fracturing Fluid

Notizen: Oxidation of Tetraline by Dioxygen. Effect of Fe(acac)3 on the Thermal and Photoinitiated Reactions

1983 ◽  
Vol 38 (10) ◽  
pp. 1293-1294 ◽  
Author(s):  
Stanislav Luňák ◽  
Marie Vašková ◽  
Josef Vepřek-Šiška
Keyword(s):  
Reaction Rate ◽  
Thermal Reaction ◽  
Photochemical Oxidation ◽  
Rate Determining Step

Abstract The photochemical oxidation of tetraline by dioxygen is catalyzed by ferric acetylacetonate (iron(III) 2,4-pentadionate), the reaction rate increasing markedly with temperature. The rate-determining step of the photochemical oxidation is presumably a catalyzed thermal reaction.

The photochemistry of complex ions: photochemical and thermal decomposition of the trioxalatocobaltate III complex

1955 ◽  
Vol 228 (1173) ◽  
pp. 252-263 ◽  
Keyword(s):  
Quantum Efficiency ◽  
Reaction Rate ◽  
Ultra Violet ◽  
Reaction Scheme ◽  
Thermal Reaction ◽  
Water Molecules ◽  
Back Reaction ◽  
Complex Ions ◽  
Excited Complex ◽  
Photochemical Quantum Yield

The photochemistry of the trioxalatocobaltate III complex was studied. It was shown that both the peak in the ultra-violet region (attributed to electron transfer) and that in the blue (attributed to d->d transitions) are photochemically active. Primary quantum efficiencies were found for various lines to be: 313 m μ , 0.365; 365 m μ , 0.345; 405 m μ , 0.085; 435 m μ , 0.06. The quantum efficiency of cobaltous ion formation is twice the primary quantum efficiency. No temperature dependence was detected. Ethyl alcohol (up to 75%) and acetone (up to 60%) did not effect the photochemical quantum yield. The radical C 2 O 4 - is postulated as intermediate capable of reducing mercuric chloride in the course of the reaction. The reaction scheme consists of photo-excitation, primary dark back-reaction, dissociation of excited complex and non-rate-determining oxidation of the C 2 O 4 - ion. The thermal reaction was also studied. It was found that the reaction rate could be presented by -d[Co Ox 3- 3 ]/d t = k 1 [Co Ox 3- 3 ]+ k 2 [H + ][Co Ox 3- 3 ] k 1 and k 2 were evaluated as 1.62 x 10 18 exp ( - 33 600/ RT ) s -1 and 1.77 x 10 19 exp ( - 32500/ RT ) s -1 (mol./l.) -1 respectively. Both the neutral and acid reactions were, however, postulated to proceed through a pseudomonomolecular mechanism involving water molecules with the [H + ] ion effecting the level of the transition state. Activation energies are discussed and finally the suitability of the trioxalatocobaltate III complex for chemical actionometry is analyzed.

scholarly journals A theoretical study of abiotic methylation reactions of gaseous elemental mercury by halogen containing molecules

2010 ◽  
Vol 10 (9) ◽  
pp. 22369-22394 ◽  
Author(s):  
L. Castro ◽  
A. Dommergue ◽  
C. Larose ◽  
C. Ferrari ◽  
L. Maron
Keyword(s):  
Experimental Data ◽  
Reaction Rate ◽  
Theoretical Study ◽  
Elemental Mercury ◽  
Thermal Reaction ◽  
Visible Range ◽  
Electronic Data ◽  
Subsequent Formation ◽  
Gaseous Elemental Mercury ◽  
Methyl Transfer

Abstract. Methylation reactions of gaseous elementary mercury by halogen containing molecules such as halogenomethane species CH3X (with X=Cl, Br and I) and the dimethylchlorinium ion CH3ClCH3+ were investigated at the DFT level. With CH3X, the reaction is predicted to be almost athermic and kinetically demanding for a thermal reaction. The reaction can proceed photochemically in the visible range; therefore sunlight may increase the reaction rate. These results compare well with the experimental data. Consecutive methylation of the CH3HgX products (with X=Cl, Br and I) and subsequent formation of CH3HgCH3 were also studied. These reactions are predicted to be kinetically inaccessible and thermodynamically unfavorable. With CH3ClCH3+, the reaction is predicted to be athermic but kinetically easy. This is due to the suitability of the methyl transfer reagent. Geometrical and electronic data were systematically analyzed in order to rationalize the results.

Extension of the Expanded Fluid Viscosity Model to Characterized Oils

2013 ◽  
Vol 27 (4) ◽  
pp. 1881-1898 ◽  
Author(s):  
H. Motahhari ◽  
M. A. Satyro ◽  
S. D. Taylor ◽  
H. W. Yarranton
Keyword(s):  
Viscosity Model ◽  
Fluid Viscosity

scholarly journals Kinetic study of HTPB (Hydroxyl Terminated Polybutadiene) Synthesis Using Infrared Spectroscopy

2020 ◽  
Vol 20 (4) ◽  
pp. 919
Author(s):  
Heri Budi Wibowo ◽  
Widhi Cahya Dharmawan ◽  
Ratih Sanggra Murti Wibowo ◽  
Adi Yulianto
Keyword(s):  
Activation Energy ◽  
Infrared Spectroscopy ◽  
Kinetic Study ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Polymerization Kinetics ◽  
Molar Ratio ◽  
First Order ◽  
Initiation Reaction ◽  
Polymer Conversion

A kinetic study of HTPB synthesis by radical polymerization of butadiene with hydrogen peroxide initiator was conducted using infrared spectroscopy. HTPB conversion was determined based on the conjunction termination rate constant, and all polymerization kinetics were evaluated to identify the constant. All polymerization steps (decomposition, initiation, propagation, conjunction, and proportional termination) can be evaluated based on polymer conversion and functionality from data provided by infrared spectroscopy. The investigation variables included the initial molar ratio of initiator to monomer (H2O2/butadiene) and the reaction temperature. These steps were assumed as the first-order reactions, giving constant reaction rates of kd, ka, kp, kt, ktc, and ktd. The reaction rates obtained for these constants were 4.2 × 10–5 sec–1, 8.9 × 10–4, 7.7 × 103, 8.5 × 107, 3.2 × 107 and 5.3 × 107 L mol–1 sec–1, respectively, with activation energy of 7608, 14188, 2247, 105, 87 and 135 kJ mol–1, respectively. The determining step of the reaction rate was identified as the initiation reaction. HTPB conversion can be measured if all polymerization kinetics constants have been evaluated.

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