scholarly journals Numerical Study of Single Iron(III) Nitrate Nonahydrate/Ethanol Droplet Evaporation in Humid Air

2020 ◽  
Author(s):  
Praveen Narasu ◽  
Alexander Keller ◽  
Maximilian Kohns ◽  
Hans Hasse ◽  
Eva Gutheil
Keyword(s):  
Numerical Study ◽  
Droplet Evaporation ◽  
Humid Air ◽  
Ethanol Droplet ◽  
Nitrate Nonahydrate

Numerical Study of Bicomponent Droplet Vaporization in a High Pressure Environment

1996 ◽  
Author(s):  
J. Stengele ◽  
H.-J. Bauer ◽  
S. Wittig
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Phase ◽  
Numerical Study ◽  
Droplet Evaporation ◽  
Single Component ◽  
Vapor Concentration ◽  
Diffusion Limit ◽  
Evaporation Process ◽  
Droplet Vaporization

The understanding of multicomponent droplet evaporation in a high pressure and high temperature gas is of great importance for the design of modern gas turbine combustors, since the different volatilities of the droplet components affect strongly the vapor concentration and, therefore, the ignition and combustion process in the gas phase. Plenty of experimental and numerical research is already done to understand the droplet evaporation process. Until now, most numerical studies were carried out for single component droplets, but there is still lack of knowledge concerning evaporation of multicomponent droplets under supercritical pressures. In the study presented, the Diffusion Limit Model is applied to predict bicomponent droplet vaporization. The calculations are carried out for a stagnant droplet consisting of heptane and dodecane evaporating in a stagnant high pressure and high temperature nitrogen environment. Different temperature and pressure levels are analyzed in order to characterize their influence on the vaporization behavior. The model employed is fully transient in the liquid and the gas phase. It accounts for real gas effects, ambient gas solubility in the liquid phase, high pressure phase equilibrium and variable properties in the droplet and surrounding gas. It is found that for high gas temperatures (T = 2000 K) the evaporation time of the bicomponent droplet decreases with higher pressures, whereas for moderate gas temperatures (T = 800 K) the lifetime of the droplet first increases and then decreases when elevating the pressure. This is comparable to numerical results conducted with single component droplets. Generally, the droplet temperature increases with higher pressures reaching finally the critical mixture temperature of the fuel components. The numerical study shows also that the same tendencies of vapor concentration at the droplet surface and vapor mass flow are observed for different pressures. Additionally, there is almost no influence of the ambient pressure on fuel composition inside the droplet during the evaporation process.

Numerical and Experimental Study of the Evaporation and Solid Layer Formation of a Bi-Component Droplet Under Various Drying Conditions

2014 ◽  
Author(s):  
Holger Grosshans ◽  
Matthias Griesing ◽  
Srikanth R. Gopireddy ◽  
Werner Pauer ◽  
Hans-Ulrich Moritz ◽  
...  
Keyword(s):  
Droplet Size ◽  
Mass Fraction ◽  
Numerical Study ◽  
Droplet Evaporation ◽  
Droplet Surface ◽  
Parameter Study ◽  
Layer Formation ◽  
Gas Temperature ◽  
Solid Layer ◽  
Initial Droplet

This paper presents a combined experimental and numerical study of the evaporation and solid layer formation of a single bi-component mannitol-water droplet in air. For spherically symmetric droplets, the problem is described mathematically by the unsteady, one-dimensional conservation equations of mass and energy. The effect of the formation of a solid layer at the droplet surface on the droplet evaporation and thermal diffusion rate is included in the present approach. The simulations are validated by comparison with experiments using acoustically levitated droplets. The study includes initial droplet diameters varying from 350 to 450 μm, gas temperatures ranging from 80 to 120 °C, and the initial mannitol mass fraction inside the droplet varies from 0.05 to 0.15. The numerical results are analyzed to identify the occurrence of solid layer formation, and the temporal evolutions of both the droplet size and mass are presented. A parameter study of the initial gas temperature, the initial droplet size, and the initial mannitol mass fraction inside the droplet on droplet evaporation and solid layer formation is presented. The present model accurately captures the initial stages of droplet drying under all conditions investigated.

Numerical study of droplet evaporation in an acoustic levitator

2018 ◽  
Vol 30 (3) ◽  
pp. 037103 ◽  
Author(s):  
Eberhard Bänsch ◽  
Michael Götz
Keyword(s):  
Numerical Study ◽  
Droplet Evaporation ◽  
Acoustic Levitator

Numerical study of properties of air heat content indicators based on stochastic models of the joint meteorological series

2019 ◽  
Vol 34 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Nina A. Kargapolova ◽  
Elena I. Khlebnikova ◽  
Vasily A. Ogorodnikov
Keyword(s):  
Time Series ◽  
Numerical Study ◽  
Heat Content ◽  
Surface Air Temperature ◽  
Heat Index ◽  
Human Beings ◽  
Humid Air ◽  
Numerical Studies ◽  
Meteorological Observations ◽  
Stochastic Properties

Abstract The paper presents results of numerical studies of stochastic properties of time series of the enthalpy of humid air and the heat index characterizing the heat content and thermal effects of humid air on human beings. The study was based on real meteorological observations and stochastic model of joint time series for surface air temperature and relative humidity taking into account daily course of real meteorological processes.

Surface temperature transition of a controllable evaporating droplet

Soft Matter ◽  
2020 ◽  
Vol 16 (41) ◽  
pp. 9568-9577
Author(s):  
Lu Shen ◽  
Junheng Ren ◽  
Fei Duan
Keyword(s):  
Surface Temperature ◽  
Droplet Evaporation ◽  
Temperature Evolution ◽  
Temperature Transition ◽  
Temperature Distributions ◽  
Ethanol Droplet ◽  
Phase Surface

Controlled ethanol droplet evaporation shows a five-phase surface temperature evolution and two transitions among the three radial surface temperature distributions.

A Numerical Study of Ethanol-Water Droplet Evaporation

2017 ◽  
Author(s):  
Giandomenico Lupo ◽  
Christophe Duwig
Keyword(s):  
Water Droplet ◽  
Composition Range ◽  
Numerical Study ◽  
Ambient Pressure ◽  
Droplet Evaporation ◽  
Droplet Temperature ◽  
Gas Phases ◽  
Initial Droplet ◽  
Liquid Phase Composition ◽  
Evaporation Dynamics

The present effort focuses on detailed numerical modelling of the evaporation of an ethanol-water droplet. The model intends to capture all relevant details of the process: it includes species and heat transport in the liquid and gas phases, and detailed thermo-physical and transport properties, varying with both temperature and composition. Special attention is reserved to the composition range near and below the ethanol/water azeotrope point at ambient pressure. For this case, a significant fraction of the droplet lifetime exhibits evaporation dynamics similar to those of a pure droplet. The results are analysed and model simplifications are examined. In particular, the assumptions of constant liquid properties, homogeneous liquid phase composition and no differential volatility may not be valid depending on the initial droplet temperature.

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