A Numerical Study of Ethanol–Water Droplet Evaporation

2017 ◽  
Vol 140 (2) ◽  
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 modeling 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 thermophysical 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 analyzed, 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.

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.

Enhanced Evaporation of Microscale Droplets With an Infrared Laser

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Luis A. Ferraz-Albani ◽  
Alberto Baldelli ◽  
Chrissy J. Knapp ◽  
Wolfgang Jäger ◽  
Reinhard Vehring ◽  
...  
Keyword(s):  
Water Droplet ◽  
Droplet Evaporation ◽  
Radiant Flux ◽  
Droplet Temperature ◽  
Ambient Conditions ◽  
Drying Time ◽  
Proposed Model ◽  
Environment Temperature ◽  
Order Of Magnitude ◽  
Surface Area Change

Enhancement of water droplet evaporation by added infrared radiation was modeled and studied experimentally in a vertical laminar flow channel. Experiments were conducted on droplets with nominal initial diameters of 50 μm in air with relative humidities ranging from 0% to 90% RH. A 2800 nm laser was used with radiant flux densities as high as 4 × 105 W/m2. Droplet size as a function of time was measured by a shadowgraph technique. The model assumed quasi-steady behavior, a low Biot number liquid phase, and constant gas–vapor phase material properties, while the experimental results were required for model validation and calibration. For radiant flux densities less than 104 W/m2, droplet evaporation rates remained essentially constant over their full evaporation, but at rates up to 10% higher than for the no radiation case. At higher radiant flux density, the surface-area change with time became progressively more nonlinear, indicating that the radiation had diminished effects on evaporation as the size of the droplets decreased. The drying time for a 50 μm water droplet was an order of magnitude faster when comparing the 106 W/m2 case to the no radiation case. The model was used to estimate the droplet temperature. Between 104 and 5 × 105 W/m2, the droplet temperature changed from being below to above the environment temperature. Thus, the direction of conduction between the droplet and the environment also changed. The proposed model was able to predict the changing evaporation rates for droplets exposed to radiation for ambient conditions varying from dry air to 90% relative humidity.

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.

Un-Shocked High Amplitude Standing Waves in Wave-Shaped Resonators

2012 ◽  
Author(s):  
Dion Savio Antao ◽  
Bakhtier Farouk
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Ambient Pressure ◽  
Standing Waves ◽  
High Amplitude ◽  
Prime Mover ◽  
Non Linear ◽  
Resonator System ◽  
Cylindrical Resonators ◽  
Linear Nature

A numerical study of non-linear, high amplitude standing waves in non-cylindrical circular resonators is reported here. These waves are shock-less and can generate peak acoustic overpressures that can exceed the ambient pressure by three/four times its nominal value. A high fidelity compressible computational fluid dynamic model is used to simulate the phenomena in cylindrical and arbitrarily shaped axisymmetric resonators. A right circular cylinder and frustum of cone are the two geometries studied. The model is validated using past numerical and experimental results of standing waves in cylindrical resonators. The non-linear nature of the harmonic response of the frustum of cone resonator system is investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude non-linear oscillations demonstrated can be used as a prime mover in a variety of applications including thermoacoustic cryocooling.

scholarly journals Study of water droplet evaporation in a mini-channel with gas flow

2016 ◽  
Vol 92 ◽  
pp. 01002
Author(s):  
Evgeniy Orlik ◽  
Ekaterina Isachenko
Keyword(s):  
Water Droplet ◽  
Gas Flow ◽  
Droplet Evaporation

Droplet Evaporation Dynamics on a Superhydrophobic Surface with Negligible Hysteresis

Langmuir ◽  
2013 ◽  
Vol 29 (34) ◽  
pp. 10785-10795 ◽  
Author(s):  
Susmita Dash ◽  
Suresh V. Garimella
Keyword(s):  
Superhydrophobic Surface ◽  
Droplet Evaporation ◽  
Evaporation Dynamics

Droplet evaporation dynamics on microstructured biphilic, hydrophobic, and smooth surfaces

2021 ◽  
Vol 62 (7) ◽  
Author(s):  
A. Alperen Günay ◽  
Moon-Kyung Kim ◽  
Xiao Yan ◽  
Nenad Miljkovic ◽  
Soumyadip Sett
Keyword(s):  
Droplet Evaporation ◽  
Smooth Surfaces ◽  
Evaporation Dynamics

Numerical Study of Flow and Cooling Characteristics of Impinging Liquid Jets on a Moving Plate

2010 ◽  
Author(s):  
Sangil Son ◽  
Gihun Son ◽  
Ilseouk Park ◽  
Piljong Lee
Keyword(s):  
Level Set ◽  
Numerical Study ◽  
Jet Impingement ◽  
Temperature Fields ◽  
Liquid Jets ◽  
Moving Plate ◽  
Gas Phases ◽  
Steel Making ◽  
Single Jet ◽  
Interfacial Motion

Liquid jet impingement on a moving plate, which is applicable to cooling of hot plates in a steel-making process, is investigated numerically by solving the conservation equations of mass, momentum and energy in the liquid and gas phases. The free-surface or liquid-gas interface is tracked by an improved level-set method incorporating a sharp-interface technique for accurate imposition of stress and heat flux conditions on the liquid-gas interface. The level-set approach is combined with a non-equilibrium k-ε turbulence model. The computations are made for multiple jets as well as a single jet to investigate their flow and cooling characteristics. Also, the effects of moving velocity of plate, jet velocity and nozzle pitch on the interfacial motion and the associated flow and temperature fields are quantified.

Dynamics of inner bubble during water droplet evaporation on conical micro-pillars surfaces

2022 ◽  
Vol 131 ◽  
pp. 105841
Author(s):  
Linsong Gao ◽  
Jizu Lyu ◽  
Zhifu Zhou ◽  
Yang Li ◽  
Dongdong Gao ◽  
...  
Keyword(s):  
Water Droplet ◽  
Droplet Evaporation ◽  
Micro Pillars
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