scholarly journals Thermodynamic Analysis of Evaporation of Levitated Binary and Ternary Liquid Fuel Droplets under Normal Gravity

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
S. Raghuram ◽  
Vasudevan Raghavan
Keyword(s):  
Gas Phase ◽  
Atmospheric Pressure ◽  
Liquid Fuel ◽  
Normal Gravity ◽  
Hydrocarbon Fuel ◽  
Droplet Surface ◽  
Liquid Equilibrium ◽  
Fuel Droplets ◽  
Ternary Fuel ◽  
Fuel Components

The present study presents a thermodynamic model for predicting the vaporization characteristics of binary and ternary hydrocarbon fuel droplets under atmospheric pressure and normal gravity conditions. The model employs activity coefficients based on UNIFAC group contribution method and evaluates the vapor-liquid equilibrium of binary and ternary droplets. The gas-phase properties have been evaluated as a function of temperature and mixture molecular weight. The model has been validated against the experimental data available in literature. The validated model is used to predict the vaporization characteristics of binary and ternary fuel droplets at atmospheric pressure under normal gravity. Results show multiple slopes in the droplet surface regression indicating preferential vaporization of fuel components based on their boiling point and volatility. The average evaporation rate is dictated by the ambient temperature and also by composition of the mixture.

Numerical Simulation of Combustion for Freely Falling Gelled Fuel Droplets under Normal Gravity Conditions

2012 ◽  
Vol 229-231 ◽  
pp. 2106-2111
Author(s):  
Ze Jun Liu ◽  
Zhen He ◽  
Xiao Ping Hu ◽  
Jian Jun Wu
Keyword(s):  
Liquid Fuel ◽  
Gas Flow ◽  
Normal Gravity ◽  
Droplet Surface ◽  
Fuel Gas ◽  
Fuel Droplets ◽  
Second Stage ◽  
Steep Temperature Gradient ◽  
Single Droplets ◽  
Vapor Region

Understanding the evaporation and combustion mechanisms of single droplets of gel propellant is the first stage to predict the burning characteristics in the combustion chamber. This paper, taking into account convection heat for freely falling gelled fuel droplets under normal gravity conditions, as well unsteady mass diffusion and thermal diffusion inside droplet, a theoretical model was developed to understand mass and heat transport mechanisms, and bubble growth within the gel droplet during processes of droplet combustion. The results show that at the first stage, shrinkage of the radius obeys the d2-law; steep temperature gradient and fuel mass concentration gradient appear within droplet, especially region near droplet surface. At the second stage, liquid fuel near the gellant layer within droplet starts to boiling, gellant layer formation resist the vaporizing fuel gas flow to extent; the vapor region appears between gellant layer and vaporizing surface within the droplet, and the droplet expands, swells, the layer thickness decreases until it ruptures.

Thermodynamic Analysis of Evaporation Characteristics of Moving Two-Component Liquid Fuel Droplets in Pre-Vaporizer Systems

2012 ◽  
Author(s):  
S. Raghuram ◽  
Vasudevan Raghavan
Keyword(s):  
Atmospheric Pressure ◽  
Liquid Fuel ◽  
Droplet Diameter ◽  
Liquid Fuels ◽  
Liquid Equilibrium ◽  
Fuel Component ◽  
Fuel Droplets ◽  
Nusselt Numbers ◽  
Two Component ◽  
Methyl Butyrate

In the current study, a thermodynamic model is presented for predicting the vaporization characteristics of moving two-component fuel droplets, at an ambient temperature of 350 K, atmospheric pressure and with an initial droplet diameter of 100 microns, as typically observed in a gas turbine pre-vaporizing system. Liquid fuels considered are iso-octane (surrogate of gasoline) and decane (surrogate of diesel), blended with ethanol and methyl-butyrate (surrogate of biodiesel), respectively. The model evaluates the vapor-liquid equilibrium based on activity coefficients calculated using UNIFAC group contribution method. The gas-phase properties are calculated as functions of temperature and mixture molecular weight. The temporally varying parameters such as equilibrium surface temperature, concentration of the higher volatile fuel component, evaporation constant and droplet Reynolds and Nusselt numbers have been studied. Variation of integrated parameters such as time-average evaporation constant, droplet lifetime, average velocity and the final droplet penetration distance are also discussed.

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.

Ammonia Gasoline-Ethanol/Methanol Tertiary Fuel Blends as an Alternate Automotive Fuel

2014 ◽  
Author(s):  
Shehan Omantha Haputhanthri ◽  
Timothy Taylor Maxwell ◽  
John Fleming ◽  
Chad Austin
Keyword(s):  
Liquid Phase ◽  
Liquid Fuel ◽  
Hydrocarbon Fuel ◽  
Phase Solubility ◽  
Test Results ◽  
Liquid Equilibrium ◽  
Fuel Blends ◽  
Automotive Fuel ◽  
Mass Basis ◽  
Dynamometer Test

Ammonia and hydrocarbon fuel blends, similar to ethanol and gasoline fuel blends can be used to commercialize ammonia as an alternative fuel. Feasibility of developing ammonia gasoline liquid fuel blends and the use of ethanol and methanol as emulsifiers to enhance the solubility of ammonia in gasoline were studied using thermostated vapor liquid equilibrium (VLE) high pressure cells, in this research. Solubility test results prove that emulsifier free pure gasoline is capable of dissolving 23 g/l of ammonia on mass basis (4.5% of ammonia on volume basis) at 345 kPa pressure and 286.65 K temperature in liquid phase. Solubility level is increased with the use of ethanol and methanol. Gasoline with 10% ethanol can retain 31.7 g/l (5.7% on volume basis) of ammonia in the liquid phase at the same pressure and temperature. Methanol has better emulsifying capabilities. Solubility level of gasoline with 30% methanol is 189.5 g/l (30.0% on volume basis). This paper presents solubility and dynamometer test results of five fuel blends E/M0, E10, M10, M20 and M30. Better performances are observed when the ammonia rich fuels are benchmarked against baseline fuel especially at higher engine speeds.

NONEQUILIBRIUM DIFFUSION COMBUSTION OF LIQUID FUEL DROPLETS AND SPRAYS MODELING

2012 ◽  
Vol 43 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Nickolay N. Smirnov ◽  
V. F. Nikitin ◽  
V. V. Tyurenkova
Keyword(s):  
Liquid Fuel ◽  
Diffusion Combustion ◽  
Fuel Droplets

Fluorescence of BODIPY Dyes in Gas Phase at near Ambient Conditions

2020 ◽  
Author(s):  
Kseniya A. Mariewskaya ◽  
Denis Larkin ◽  
Yuri Samoilichenko ◽  
Vladimir Korshun ◽  
Alex Ustinov
Keyword(s):  
Gas Phase ◽  
Molecular Interactions ◽  
Atmospheric Pressure ◽  
Fluorescence Spectra ◽  
Visible Range ◽  
Intrinsic Properties ◽  
Ambient Conditions ◽  
Ideal Model ◽  
Molecular Fluorescence ◽  
Tesla Coil

Molecular fluorescence is a phenomenon that is usually observed in condensed phase. It is strongly affected by molecular interactions. The study of fluorescence spectra in the gas phase can provide a nearly-ideal model for the evaluation of intrinsic properties of the fluorophores. Unfortunately, most conventional fluorophores are not volatile enough to allow study of their fluorescence in the gas phase. Here we report very bright gas phase fluorescence of simple BODIPY dyes that can be readily observed at atmospheric pressure using conventional fluorescence instrumentation. To our knowledge, this is the first example of visible range gas phase fluorescence at near ambient conditions. Evaporation of the dye in vacuum allowed us to demonstrate organic molecular electroluminescence in gas discharge excited by electric field produced by a Tesla coil.

Vapour-liquid equilibrium in the isobutyl formate-isobutyl alcohol and n-butyl formate-isobutyl alcohol systems at atmospheric pressure

1979 ◽  
Vol 44 (12) ◽  
pp. 3501-3508 ◽  
Author(s):  
Jan Linek
Keyword(s):  
Experimental Data ◽  
Fourth Order ◽  
Atmospheric Pressure ◽  
Isobutyl Alcohol ◽  
Liquid Equilibrium ◽  
The Third

Isobaric vapour-liquid equilibria in the isobutyl formate-isobutyl alcohol and n-butyl formate-isobutyl alcohol systems have been measured at atmospheric pressure. A modified circulation still of the Gillespie type has been used for the measurements. The experimental data have been correlated by means of the third- and fourth-order Margules equations.

Liquid-liquid equilibrium in binary glycols-toluene and glycols-xylene systems

1982 ◽  
Vol 47 (6) ◽  
pp. 1686-1694 ◽  
Author(s):  
Lumír Mandík ◽  
František Lešek
Keyword(s):  
Atmospheric Pressure ◽  
Binary Systems ◽  
Liquid Equilibrium ◽  
Benzene Toluene

Liquid-liquid equilibria were determined in the following binary systems: 1,2-ethandiol/toluene, 1,2-ethandiol/xylene, 1,2-propandiol/toluene, 1,2-propandiol/xylene, 1,4-butandiol/toluene, 1,4-butandiol/xylene, 1,3-butandiol/toluene, 1,3-butandiol/xylene, 1,3-butandiol/p-xylene, 2,2'-dioxydiethanol/toluene, 2,2'-dioxydiethanol/xylene. The solubility of 2,2-dimethyl-1,3-propandiol in benzene, toluene and xylene was also measured. Critical solubility temperatures at atmospheric pressure were determined for systems containing 1,2-propandiol and 1,3-butandiol.

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