Simulation on Coal Devolatilization Combined a Multi-Step Kinetic Model with Chemkin Software

2012 ◽  
Vol 608-609 ◽  
pp. 1375-1382
Author(s):  
Rui Zhang ◽  
Qin Hui Wang ◽  
Zhong Yang Luo ◽  
Meng Xiang Fang
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Intermediate Product ◽  
Coal Combustion ◽  
Model Complexity ◽  
Coal Pyrolysis ◽  
Simple Application ◽  
Calculation Results ◽  
Simulation Results ◽  
Good Agreement

As the first step in coal combustion and gasification, coal devolatilization has significant effect on reaction process. Previous coal devolatilization models have some disadvantages, such as poor flexibility, model complexity, and requirement of characterization parameters. Recently, Sommariva et al. have proposed a multi-step kinetic model of coal devolatilization. This model avoids the disadvantages mentioned above and can predict elemental composition of tar and char. In this paper, the mechanism of this model has been revised for simple application to Chemkin. Revision method is that some reactions are split into more reactions by using one pseudo-intermediate-product to replace several final products. Simulation results show that calculation results from revised mechanism compare quite well with that from original mechanism and have good agreement with experimental data. The revised mechanism is accurate and can be applied to Chemkin very easily, which gives it wide application to simulation of coal pyrolysis, gasification and combustion.

Theoretical Model And Computer Simulation Results Of Enhanced Diffusion Of High-Temperature Implanted Aluminum In Silicon Carbide

1997 ◽  
Vol 483 ◽  
Author(s):  
G. V. Gadiyak
Keyword(s):  
Experimental Data ◽  
Silicon Carbide ◽  
Kinetic Model ◽  
Enhanced Diffusion ◽  
Al Content ◽  
Mobile Species ◽  
Simulation Results ◽  
Doping Profiles ◽  
Sic Films ◽  
Good Agreement

AbstractWide applications of silicon carbide (SiC) films in microelectronics devices make especially important predictions of the doping profiles during and/or after thermal treatment. A macroscopic kinetic model of enhanced diffusion of aluminum in SiC films during ion bombardment at high temperatures has been considered. The set of equations describing the kinetic model takes into account generation Vc and Csi vacancies during bombardment, migration of mobile species (Al) toward the surface and reactions of Al atoms with Vc and Vsi vacancies, as well as Al evolution from the film. The calculations were carried out for the flux of Al ions with energy 40 keV and current density 20 μA/cm2 to a dose 2 1016 cm−2 at 1800° C. The calculations have shown that the Al content in SiC at these condition does not exceed 40%. The calculation profile of Al is in a good agreement with experimental data [1].

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

scholarly journals ANALYSIS OF THE CURRENT STATE OF RESEARCHES OF THE DEPOSITION OF ASPHALT-RESINOUS SUBSTANCES, PARAFFIN, AND MODELING METHODS. REVIEW PART II: WAX DEPOSITION

2021 ◽  
pp. 13-23
Author(s):  
M.R. Manafov ◽  
◽  
G.S. Aliyev ◽  
A.I. Rustamova ◽  
V.I. Kerimli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Deposition Process ◽  
Real Field ◽  
Wax Deposition ◽  
Scaling Effect ◽  
Modeling Methods ◽  
Current State ◽  
Simulation Results ◽  
Reliable Interpretation

The mechanism of paraffin formation in transport pipes is briefly discussed. A kinetic model of the formation and wax deposition from oil is proposed. Comparison of the model with the available experimental data gave satisfactory results. The review considers software tools for modeling the wax deposition process. It is noted that the simulation results are not always applicable to real field cases. For a more reliable interpretation, the scaling effect must be taken into account. In the work various technologies for wax removal are considered

New module for channeling radiation simulation in Geant4

2021 ◽  
Vol 16 (12) ◽  
pp. P12042
Author(s):  
A.A. Savchenko ◽  
W. Wagner
Keyword(s):  
Experimental Data ◽  
Single Crystals ◽  
Dipole Approximation ◽  
Relativistic Electrons ◽  
Planar Channeling ◽  
Classical Approach ◽  
Electrons And Positrons ◽  
Simulation Results ◽  
Channeling Radiation ◽  
Good Agreement

Abstract We present a new C++ module for simulation of channeling radiation to be implemented in Geant4 as a discrete physical process. The module allows simulation of channeling radiation from relativistic electrons and positrons with energies above 100 MeV for various types of single crystals. In this paper, we simulate planar channeling radiation applying the classical approach in the dipole approximation as a first attempt not yet considering other contributory processes. Simulation results are proved to be in a rather good agreement with experimental data.

THE CORRELATION BETWEEN BOND ANGLE DISTRIBUTION AND THE COORDINATION OF SILICA LIQUID UNDER PRESSURE

2012 ◽  
Vol 26 (20) ◽  
pp. 1250117 ◽  
Author(s):  
L. T. VINH ◽  
N. V. HUY ◽  
P. K. HUNG
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Bond Angle ◽  
Simple Expression ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Bond Angle Distribution ◽  
Simulation Results ◽  
Substantial Change ◽  
Good Agreement

Molecular dynamics simulation is carried out for liquid SiO 2 at pressure ranged from zero to 30 GPa and by using BKS, Born–Mayer type and Morse–Stretch potentials. The constructed models reproduce well the experimental data in terms of mean coordination number, bond angle and pair radial distribution function. Furthermore, the density of all samples can be expressed by a linear function of fractions SiO x. It is found that the topology of units SiO x and linkages OSi y is unchanged upon compression although the liquid undergoes substantial change in its network structure. Consequently, the partial bond angle distribution for SiO x and OSi y is identical for all samples constructed by the same potential. This result allows to establishing a simple expression between total bond angle distribution (BAD) and fraction of SiO x and OSi y. The simulation shows a good agreement between the calculation and simulation results for both total O–Si–O and Si–O–Si BADs. This supports a technique to estimate amount of units SiO x and linkages OSi y on base of total Si–O–Si and O–Si–O BADs measured experimentally.

Characterization of effects of selected organic substances on decomposition of hydrogen peroxide during Fenton reaction

2004 ◽  
Vol 49 (4) ◽  
pp. 129-134 ◽  
Author(s):  
K.C. Namkung ◽  
A. Aris ◽  
P.N. Sharratt
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Fenton Reaction ◽  
Reactive Black 5 ◽  
Organic Substances ◽  
Oxidation Model ◽  
Simulation Results ◽  
Good Agreement

This study aims to investigate the effects of selected organic substances on the degradation of hydrogen peroxide during the Fenton reaction. Since the presence of organic substances can strongly affect the mechanism of the Fenton reaction, the information on effects of organic substances on the reaction would be a vital guide to the success of its application to the destruction of organics in wastewater. Several organic compounds having different structures were selected as model pollutants: 4-chlorophenol, 1,4-dioxane, chloroform, a dye (reactive black-5), and EDTA. Oxidation of 4-chlorophenol and reactive black-5 resulted in enormously fast degradation of hydrogen peroxide, while others such as 1,4-dioxane and chloroform showed much slower degradation. These experimental data were compared to simulation results from a computational model based on a simple áOH-driven oxidation model. Modelling results for chloroform and 1,4-dioxane were in relatively good agreement with the experimental data, while those for 4-chlorophenol and reactive black-5 were very different from the experimental data. The results for EDTA showed a different trend to those for other compounds. From these results, classification of organic substances into several sub-groups was tried.

In-plane Thermal and Electronic Transport in Quantum Dot Superlattice

2001 ◽  
Vol 677 ◽  
Author(s):  
A. Khitun ◽  
J.L. Liu ◽  
K.L. Wang ◽  
G. Chen
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Quantum Dot ◽  
Electronic Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Host Materials ◽  
Simulation Results ◽  
Germanium Quantum Dots ◽  
Good Agreement

ABSTRACTWe present a theoretical model in order to describe both thermal and electronic in-plane transports in quantum dot superlattice. The model takes into account the modifications of electron and phonon transport due to the space confinement caused by the mismatch in electronic and thermal properties between dot and host materials. The developed model provides the analysis of the in-plane superlattice electronic and thermal properties versus quantum dot size and their arrangement. Numerical calculations were carried out for a structure that consists of multiple layers of Si with regimented germanium quantum dots. The simulation results of the lattice thermal conductivity are in a good agreement with experimental data.

Pemuatan listrik bipolar untuk partikel aerosol

2018 ◽  
Vol 4 (3) ◽  
pp. 287
Author(s):  
Heru Setyawan
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Ion Mobility ◽  
Opposite Sign ◽  
Aerosol Particles ◽  
Calculation Results ◽  
Two Parameters ◽  
Diffusion Charging ◽  
Fuchs Theory ◽  
Good Agreement

Bipolar diffusion charging of aerosol particles has been studied theoretically using Fuchs theory. Experimental data measured by several researchers available in the published literature were used to verify the calculation results. The calculation results show that Fuchs theory has been successfully used to predict the experimental data of the charging probability of submicron aerosol particles. The combination probability of ion-particle increases with the increase of particle size, both for particle and ion with the same sign and those with the opposite sign. However the combination probability is larger if the charges of particle and ion are of the opposite sign. Generally, Fuchs theory is not too easy to deal with due to the ill-defined of all parameters used, namely ion mass and ion mobility. These cause many possibilities of parameter combination that can give a good agreement with experimental data. Thus, in order to interpret the experimental results properly, the two parameters should be measured simultaneously with aerosol measurements.Keywords: Aerosol, Bipolar Charging, Combination ProbabilityAbstrakPemuatan listrik difusi bipolar partikel aerosol telah dipelajari secara teoritis menggunakan teori Fuchs. Sebagai verifikasi digunakan data eksperimen beberapa peneliti yang tersedia dalam literatur yang telah dipublikasikan. Hasil perhitungan menunjukkan bahwa teori Fuchs berhasil memprediksi dengan baik data eksperimen probabilitas pemuatan listrik partikel aerosol dalam rentang ukuran partikel berukuran submikron. Probabilitas penggabungan ion-partikel semakin besar dengan semakin besarnya ukuran partikel, baik untuk partikel dan ion yang memiliki tanda yang berlawanan maupun yang memiliki tanda yang sama. Akan tetapi, probabilitas penggabungan untuk partikel dan ion yang memiliki tanda yang berlawanan memiliki nilai yang lebih besar. Pada umumnya teori Fuchs tidak terlalu mudah untuk digunakan yang disebabkan oleh tidak terdefinisikannya dengan baik semua parameter yang digunakan, yaitu  massa ion dan mobilitas ion. Hal ini mengakibatkan banyak kemungkinan kombinasi parameter yang bisa menghasilkan kesesuaian yang bagus dengan data hasil pengukuran. Jadi, agar dapat menginterpretasikan hasil pengukuran dengan tepat, kedua besaran tersebut harus diukur secara serempak denganpengukuran aerosol.Kata Kunci: Aerosol, Pemuatan Listrik Bipolar, Probabilitas Penggabungan

Prediction of Solid-Liquid Interface Stability and Dendritic Growth in Multi-Component Alloys with Calphad Method

2005 ◽  
Vol 475-479 ◽  
pp. 2721-2724
Author(s):  
Rui Jie Zhang ◽  
Zhi He ◽  
Wan Qi Jie
Keyword(s):  
Experimental Data ◽  
Present Method ◽  
Dendritic Growth ◽  
Calphad Method ◽  
Liquid Interface ◽  
Interface Stability ◽  
Calculation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Good Agreement

A method to predict the solid-liquid interface stability and the constrained dendrite growth of multi-component alloys was developed based on the Calphad method. The method was applied to several industrial Al-Si-Mg alloys, and the predicted results were compared with some former experimental data. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.

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