scholarly journals Clouds Over Soot Evaporation: Errors in Modeling Laser-Induced Incandescence of Soot

2000 ◽  
Vol 123 (4) ◽  
pp. 814-818 ◽  
Author(s):  
G. J. Smallwood ◽  
D. R. Snelling ◽  
F. Liu ◽  
O¨. L. Gu¨lder
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Evaporation Process ◽  
Thermal Velocity ◽  
Carbon Vapor ◽  
Evaporation Model ◽  
Correct Formulation ◽  
Intense Evaporation ◽  
Laser Induced Incandescence ◽  
Heat Of Evaporation

The ambiguity and incorrect treatment of the evaporation term among some LII models in the literature are discussed. This study does not suggest that the correct formulation presented for the evaporation model is adequate, or that it reflects the soot evaporation process under intense evaporation. The emphasis is that the current evaporation model must be used correctly in the evaluation of the LII model against experimental data. Numerical results are presented to demonstrate the significance of the molecular weight associated with the heat of evaporation and the thermal velocity of carbon vapor on the results obtained with the evaporation model. Other errors frequently repeated in the literature are also identified.

Validation of Film Evaporation Model in GASFLOW-MPI

2018 ◽  
Author(s):  
Li Yabing ◽  
Zhang Han ◽  
Xiao Jianjun
Keyword(s):  
Experimental Data ◽  
Wall Temperature ◽  
Cooling System ◽  
Numerical Study ◽  
Thermal Power ◽  
Heat Removal ◽  
Air Velocity ◽  
Evaporation Model ◽  
Film Evaporation ◽  
Test Region

A dynamic film model is developed in the parallel CFD code GASFLOW-MPI for passive containment cooling system (PCCS) utilized in nuclear power plant like AP1000 and CAP1400. GASFLOW-MPI is a widely validated parallel CDF code and has been applied to containment thermal hydraulics safety analysis for different types of reactors. The essential issue for PCCS is the heat removal capability. Research shows that film evaporation contributes most to the heat removal capability for PCCS. In this study, the film evaporation model is validated with separate effect test conducted on the EFFE facility by Pisa University. The test region is a rectangle gap with 0.1m width, 2m length, and 0.6m depth. The water film flowing from the top of the gap is heated by a heating plate with constant temperature and cooled by countercurrent air flow at the same time. The test region model is built and analyzed, through which the total thermal power and evaporation rate are obtained to compare with experimental data. Numerical result shows good agreement with the experimental data. Besides, the influence of air velocity, wall temperature and gap widths are discussed in our study. Result shows that, the film evaporation has a positive correlation with air velocity, wall temperature and gap width. This study can be fundamental for our further numerical study on PCCS.

scholarly journals Geoeconomic interest of minerals assemblage of sebkha El Melah, southeastern Tunisia

2021 ◽  
Author(s):  
Elhoucine Essefi ◽  
Mohamed Ali Tagorti
Keyword(s):  
Experimental Data ◽  
Evaporation Rate ◽  
Mineralogical Composition ◽  
Theoretical Modeling ◽  
Natural Process ◽  
Cumulative Number ◽  
Economic Interest ◽  
Evaporation Process ◽  
Mineral Precipitation ◽  
Accessory Minerals

Abstract This work aimed to study the formation of salt through a progressive evaporation of sebkha El Melah brine. The precipitated salt in the case of sebkha El Melah is variable along the progressive evaporation. Weights of salt after each phase of precipitation indicate a heterogeneous evaporation process cumulating at 315 g L−1. With an increasing evaporation of El Melah brine, the number of precipitated mineral species increased. The cumulative number of species along the evaporation process reached 20, including principally: Halite (NaCl) (73–95%), epsomite (MgSO4·7H2O) (7–14%), bischofite (MgCl2:6H2O) (1%), Kieserite Mg(SO4)(H2O) (0–2%), magnesite (MgCO3) (1–4%), polyhalite (K2Ca2Mg(SO4)4,2H2O). Also, the thermodynamic theoretical modeling of the El Melah brine shows convergence with geochemical and mineralogical experimental data. At an evaporation rate of 60%, the sebkha of El Melah annually provides with 315,000 tons of salt. The majority of salt (80%) is halite. The remaining 20% contains different species having a huge economic interest. From an industrial viewpoint, our study shows that the purity of halite is guaranteed at low rates of evaporation. Evaporation between 50 and 75% produces a mixture dominated by halite. Evaporation higher than 75% needs further studies to find the mineralogical composition and the phase of each mineral precipitation. The saline system of El Melah represents a geoeconomic interest due to the cheap natural process of production, its large quantity of halite with varieties of other accessory minerals, and cheap procedure of exportation.

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

Modelling the Natural Evaporation of the Concentrated Seawater after Desalinized

2015 ◽  
Vol 713-715 ◽  
pp. 2989-2992
Author(s):  
Xue Kui Wang ◽  
Ying Zhou ◽  
Ling Li ◽  
Tian Cheng Gao ◽  
Na Tang
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Artificial Neural Network ◽  
Relative Humidity ◽  
Evaporation Rate ◽  
Evaporation Model ◽  
Irradiation Intensity ◽  
Artificial Neural ◽  
Good Agreement

The influence of natural evaporation factors (the irradiation intensity, speed of the wind, temperature of the brine, temperature and relative humidity of the air) on the desalinated seawater evaporation rate was measured experimentally. A natural evaporation model was built by correlating the experimental data using the artificial neural network. This model was well correlated with the influence of natural evaporation factors, and it showed a good agreement of the results and evaporation theory.

Characteristics of a Solar Pond Brine Reconcentration System

1994 ◽  
Vol 116 (2) ◽  
pp. 69-73 ◽  
Author(s):  
T. A. Newell ◽  
M. K. Smith ◽  
R. G. Cowie ◽  
J. M. Upper ◽  
C. L. Cler
Keyword(s):  
Experimental Data ◽  
Electrical Energy ◽  
Energy Requirements ◽  
Evaporation Process ◽  
Evaporation Surface ◽  
University Of Illinois ◽  
Solar Pond ◽  
Salt Gradient ◽  
The University ◽  
Good Agreement

An active brine reconcentration system has been incorporated into the design of the University of Illinois half-acre salt gradient solar pond facility. An important feature of the system is its ability to keep precipitation from diluting the brine. Experimental data presented is in good agreement with a numerical simulation model of the evaporation process. The “film”-type evaporation process used in the system efficiently collects solar energy for evaporating water from brine. Parasitic electrical energy requirements for the evaporation system are 1.2 watts per square meter of evaporation surface area.

Effects of Reaction Temperature on Hydrocracking of Asphaltene over NiMo/γ-Al2O3

2011 ◽  
Vol 393-395 ◽  
pp. 1189-1192
Author(s):  
Ying Xian Zhao ◽  
Bo Shen
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Molecular Weight ◽  
Kinetic Equation ◽  
Apparent Activation Energy ◽  
Average Molecular Weight ◽  
Liquid Product ◽  
Order Kinetic ◽  
Increasing Temperature ◽  
Order Kinetic Equation

The hydrocracking of a pentane-insoluble asphaltene over NiMo/γ-Al2O3 at 623 - 703 K was investigated. The second order kinetic equation fits experimental data of asphaltene conversion adequately, giving the apparent activation energy to be 144 kJ/mol over the temperature range. Average molecular weight of liquid product was reduced significantly with increasing temperature.

Kinetics of the radical copolymerization of styrene and 2-methoxyethyl methacrylate

1983 ◽  
Vol 48 (9) ◽  
pp. 2656-2665 ◽  
Author(s):  
Jaroslav Stejskal ◽  
Dagmar Straková ◽  
Ondřej Procházka ◽  
Pavel Kratochvíl
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Kinetic Data ◽  
Radical Copolymerization ◽  
Copolymer Composition ◽  
Monomer Mixture ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Best Fit ◽  
Copolymerization Kinetics

Twenty low-conversion statistical copolymers of styrene and 2-methoxyethyl methacrylate with various composition were prepared. The dependence of the copolymer composition, molecular weight, initiation efficiency and other parameters on the composition of the monomer mixture is discussed. Kinetic data are correlated by means of various models of the copolymerization kinetics. The best fit with experimental data is provided by a diffusion-controlled termination model, especially its dyad variant suggested in this study.

The Solvation of High Molecular Substances, Especially Rubber

1930 ◽  
Vol 3 (3) ◽  
pp. 409-417
Author(s):  
P. Stamberger ◽  
C. M. Blow
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Vapor Pressure ◽  
Swelling Pressure ◽  
Viscosity Measurements ◽  
Molecular Substances ◽  
Dissolved Phase

Abstract 1. On the basis of new experimental data on rubber, the theories of the solvation of high molecular substances are discussed. 2. In this discussion the measurements of the swelling pressure of rubber in toluene are described. The values obtained, and also the measurements of the depression of the vapor pressure lead to the conclusion that rubber cannot be considered a mixture of homologous polymers. 3. The consistency or viscosity of gels is without effect on the decrease in the activity of the solvent (measured by the depression of the vapor pressure and the swelling pressure). 4. The conclusion is drawn that mastication cannot be considered a depolymerization. 5. On the basis of measurements of the viscosity of solutions of rubber-gas black compounds it follows that conclusions as to the molecular weight of the dissolved phase cannot be drawn from viscosity measurements without further ado. 6. The theories of the distribution of high molecular substances in solution are briefly discussed.

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