Fuel Droplet Heating and Evaporation: Analysis of Liquid and Gas Phase Models

2007 ◽  
Author(s):  
S. S. Sazhin ◽  
T. Kristyadi ◽  
M. R. Heikal ◽  
W. A. Abdelghaffar ◽  
I. N. Shishkova
Keyword(s):  
Gas Phase ◽  
Fuel Droplet ◽  
Phase Models

Comparative Analysis of Gas Phase Models for Fuel Droplet Evaporation in Forced Convection

2012 ◽  
Vol 516-517 ◽  
pp. 872-875
Author(s):  
Peng Zhao ◽  
Guo Xiu Li ◽  
Yu Song Yu ◽  
Ye Yuan ◽  
Hong Meng Li
Keyword(s):  
Gas Phase ◽  
Forced Convection ◽  
Droplet Evaporation ◽  
Phase Model ◽  
Fuel Droplet ◽  
Evaporation Time ◽  
Stefan Flow ◽  
Basic Relationship ◽  
Phase Models ◽  
Relationship Of

In this study, mathematical model of fuel droplet evaporation is developed. Basic relationship of gas phase model is proposed by summarizing a large number of droplet evaporation gas phase models. Predictions of gas phase model are compared in forced convection. The results show that: Predictions are strongly dependent on the choice of gas phase models. Predictions of Ranz model and Haywood model are accurate with the experimental results. Evaporation time which is predicted by the gas phase models considering Stefan flow is longer than those without considering Stefan flow. For different gas phase models, droplet evaporation time is directly proportional to environmental pressure and inversely proportional to ambient temperature and Reynolds number.

Gas-phase models of γ turns: Effect of side-chain/backbone interactions investigated by IR/UV spectroscopy and quantum chemistry

2005 ◽  
Vol 123 (8) ◽  
pp. 084301 ◽  
Author(s):  
Wutharath Chin ◽  
François Piuzzi ◽  
Jean-Pierre Dognon ◽  
Iliana Dimicoli ◽  
Michel Mons
Keyword(s):  
Quantum Chemistry ◽  
Gas Phase ◽  
Uv Spectroscopy ◽  
Side Chain ◽  
Phase Models

scholarly journals Gas‐Phase Models for the Nickel‐ and Palladium‐Catalyzed Deoxygenation of Fatty Acids

ChemCatChem ◽  
2020 ◽  
Vol 12 (21) ◽  
pp. 5476-5485 ◽  
Author(s):  
Kevin Parker ◽  
Geethika K. Weragoda ◽  
Victoria Pho ◽  
Allan J. Canty ◽  
Anastasios Polyzos ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Gas Phase ◽  
Palladium Catalyzed ◽  
Phase Models

A Semi-Analytical Model for Evaporating Fuel Droplets

2005 ◽  
Vol 127 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Achintya Mukhopadhyay ◽  
Dipankar Sanyal
Keyword(s):  
Gas Phase ◽  
Computational Cost ◽  
Lewis Number ◽  
Droplet Evaporation ◽  
Solution Procedure ◽  
Droplet Surface ◽  
Spray Combustion ◽  
Fuel Droplet ◽  
Cfd Model ◽  
Fuel Droplets

An algorithm for solution of a model for heating and evaporation of a fuel droplet has been developed. The objective of the work is to develop a computationally economic solution module for simulating droplet evaporation that can be incorporated in spray combustion CFD model that handles a large number of droplets. The liquid-phase transient diffusive equation has been solved semi-analytically, which involves a spatially closed-form and temporally discretized solution procedure. The model takes into account droplet surface regression, nonunity gas-phase Lewis number and variation of latent heat with temperature. The accuracy of the model is identical to a Finite Volume solution obtained on a very fine nonuniform grid, but the computational cost is significantly less, making this approach suitable for use in a spray combustion code. The evaporation of isolated heptane droplet in a quiescent ambient has been investigated for ambient pressures of 1 to 5 bar.

scholarly journals Homogeneous gas phase models of relaxation kinetics in neon afterglow

2007 ◽  
Vol 5 (1) ◽  
pp. 33-44 ◽  
Author(s):  
Vidosav Markovic ◽  
Sasa Gocic ◽  
Suzana Stamenkovic
Keyword(s):  
Experimental Data ◽  
Time Delay ◽  
Gas Phase ◽  
Number Density ◽  
Relaxation Kinetics ◽  
Particle Decay ◽  
Breakdown Time ◽  
Active Particles ◽  
Effective Coefficients ◽  
Phase Models

The homogeneous gas phase models of relaxation kinetics (application of the gas phase effective coefficients to represent surface losses) are applied for the study of charged and neutral active particles decay in neon afterglow. The experimental data obtained by the breakdown time delay measurements as a function of the relaxation time td (?) (memory curve) is modeled in early, as well as in late afterglow. The number density decay of metastable states can explain neither the early, nor the late afterglow kinetics (memory effect), because their effective lifetimes are of the order of milliseconds and are determined by numerous collision quenching processes. The afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular neon Ne2 + and nitrogen ions N2 + (present as impurities) and the approximate value of N2 + ambipolar diffusion coefficient is determined. After the charged particle decay, the secondary emitted electrons from the surface catalyzed excitation of nitrogen atoms on the cathode determine the breakdown time delay down to the cosmic rays and natural radioactivity level. Due to the neglecting of number density spatial profiles, the homogeneous gas phase models give only the approximate values of the corresponding coefficients, but reproduce correctly other characteristics of afterglow kinetics from simple fits to the experimental data.

Understanding Energy Transfer in Gas–Surface Collisions from Gas-Phase Models

2014 ◽  
Vol 118 (5) ◽  
pp. 2609-2621 ◽  
Author(s):  
Juan J. Nogueira ◽  
William L. Hase ◽  
Emilio Martínez-Núñez
Keyword(s):  
Energy Transfer ◽  
Gas Phase ◽  
Phase Models

scholarly journals Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

2012 ◽  
Vol 12 (10) ◽  
pp. 27053-27076 ◽  
Author(s):  
J. Mao ◽  
S. Fan ◽  
D. J. Jacob ◽  
K. R. Travis
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Catalytic Mechanism ◽  
Transition Metal Ions ◽  
Hydroperoxyl Radical ◽  
Model Predictions ◽  
Atmospheric Observations ◽  
Gas Standard ◽  
Phase Models

Abstract. The hydroperoxyl radical (HO2) is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involve conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions (TMI) Cu(I)/Cu(II) and Fe(II)/Fe(III) to rapidly convert HO2 to H2O in aerosols. The implied HO2 uptake significantly affects global model predictions of tropospheric OH, ozone, and other species, improving comparisons to observations, and may have a major and previously unrecognized impact on atmospheric oxidant chemistry.

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