Effects of the Thickness of Boundary Layer on Droplet’s Evaporation Rate

2020 ◽  
Vol 64 (5) ◽  
pp. 50402-1-50402-11
Author(s):  
P. Jonglearttrakull ◽  
K. Fushinobu ◽  
M. Kadonaga
Keyword(s):  
Boundary Layer ◽  
Evaporation Rate ◽  
Ethanol Concentration ◽  
Distribution Area ◽  
Water Mixture ◽  
Schlieren Visualization ◽  
Increase With Increase ◽  
Vapor Distribution ◽  
Vapor Region

Abstract The evaporation rate of a droplet was explained in relation to the thickness of the boundary layer and the condition near the droplet’s surface. However, the number of results obtained from experiments is very limited. This study aims to investigate the thickness of the boundary layer of an ethanol‐water mixture droplet and its effect on the evaporation rate by Z-type Schlieren visualization. Single and double droplets are tested and compared to identify the effect of the second droplet on the average and instantaneous evaporation rate. The double droplet’s lifetime is found to be longer than the single droplet’s lifetime. The formation of a larger vapor region on the top of the droplet indicates a higher instantaneous evaporation rate. The thickness of the boundary layer is found to increase with increase in ethanol concentration. Furthermore, a larger vapor distribution area is found in the case of higher ethanol concentration, which explains the faster evaporation rate at higher ethanol concentration.

scholarly journals Noninvasive Determination of the Amount of Ethanol in Liquid Mixtures by Ultrasound Using Bilinear Interpolation Method

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Ahmet Aydın ◽  
Cemil Keskinoğlu ◽  
Umut Kökbaş ◽  
Abdullah Tuli
Keyword(s):  
Ethanol Concentration ◽  
Liquid Mixture ◽  
Interpolation Method ◽  
Ultrasonic Method ◽  
Liquid Mixtures ◽  
Water Mixture ◽  
Bilinear Interpolation ◽  
Destructive Effect ◽  
El Sistema

Ultrasound is used in many analysis studies, including liquid mixtures. Many mixtures are analyzed to understand their contents or properties in different situations. One of these mixtures is the ethanol-water combination. In this study, the amount of ethanol in the liquid mixture was determined noninvasively by the ultrasonic method using a microcontroller-based system. The results show that the measurements obtained were within the p<0.05 confidence interval. The characteristics evaluation of the system shows that the system can detect ethanol concentration as low as 0.552 g/L, thus the system has a broad and linear determination range for ethanol. Although the system is calibrated and tested with ethanol-water mixture, it can be used for any mixture that changes density related to the substance concentration, including different alcohols which are soluble in water (glycols, glycoethers, etc.) or any other material (solid or liquid) which is soluble in alcohol or different liquid solvent. The system has so many advantages that make it possible to use comfortably in many areas where the amount of ethanol contained in the mixture is essential. These advantages are the high accuracy and sensitivity, being noninvasive, portable, and not having a destructive effect on the substance.   Resumen. El ultrasonido es utilizado en muchos estudios incluyendo las mezclas liquidas. Se analizan varias mezclas para entender sus contenidos y propiedades en diferentes situaciones. Una de estas mezclas es la combinación de etanol-agua. En este estudio, la cantidad de etanol en la mezcla líquida fue determinada de manera no invasiva con el método ultrasonico utilizando un sistema basado en microcontrolador. Los resultados muestran que las mediciones obtenidas se encontraban dentro de un intervalo de confianza de p<0.05. Las características de evaluación del sistema muestran que se puede detectar etanol a una concentración tan baja como 0.552 g/L, por lo tanto, el sistema tiene un rango de determinación linear amplio para etanol. Aunque el sistema se calibra y prueba con mezcla de etanol-agua, puede ser utilizado para cualquier mezcla que cambia de densidad en relación con la concentración de la substancia, incluyendo diferentes alcoholes que son solubles en agua (glicoles, glicoeteres, etc) o cualquier otro material (sólido o líquido) que sea soluble en alcohol o en algún solvente líquido diferente. El sistema tiene muchas ventajas que hacen posible su utilización en muchas áreas donde la cantidad de etanol contenida en la mezcla es esencial. Estas ventajas son de alta precisión y sensiblididad al ser no invasivo, portátil y al no tener un efecto destructivo sobre la sustancia.

The Evaporation of Oil Spills: Development and Implementation of New Prediction Methodology

1999 ◽  
Vol 1999 (1) ◽  
pp. 281-287 ◽  
Author(s):  
Mervin F. Fingas
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Evaporation Rate ◽  
Oil Spills ◽  
Initial Step ◽  
Transfer Coefficients ◽  
Sea Temperature ◽  
Step Over ◽  
Simple Equations ◽  
Velocity Turbulence

ABSTRACT Extensive experimentation was conducted on oil evaporation. The results of the regulation nature of oil evaporation experiments, show that oil is not strictly boundary-layer regulated specifically: (1) the evaporation rate of several oils with increasing wind speed shows that, unlike water, the evaporation rate does not change significantly except for the initial step over 0-level wind; (2) increasing area does not significantly change oil evaporation rate; (3) decreasing thickness does not increase oil evaporation rate; (4) the volume or mass of oil evaporating correlates with the evaporation rate; (5) evaporation of pure hydrocarbons with and without wind (turbulence) shows that compounds larger than nonane and decane are not boundary-layer regulated. The fact that oil evaporation is not strictly boundary-layer regulated implies a simplistic evaporation equation will suffice to describe the process. A simple equation of the form, evaporation = constant × logarithm of time, is sufficient to describe evaporation. The following processes do not require consideration: wind velocity, turbulence level, area, thickness, and scale size. The factors found to be important to evaporation are time and temperature. The equation parameters found experimentally for the evaporation of oils can be related to commonly-available distillation data for the oil. Specifically, it has been found that the distillation percentage at 180°C correlates well with the equation parameters. Relationships enabling calculation of evaporation equations directly from distillation data have been developed. These equations were combined with the equations generated to account for the temperature variations. The results have application in oil spill prediction and modelling. The simple equations can be applied using readily-available data such as sea temperature and time. Old equations required oil vapour pressure, specialised distillation data, spill area, wind speed, and mass transfer coefficients, all of which are difficult to obtain.

scholarly journals Influence of Ethanol Concentration and Template Ion Exchange Agent on Template Recycling in Mobil Crystalline Material 41 (MCM-41) Synthesis

2020 ◽  
Vol 19 (2) ◽  
pp. 130
Author(s):  
Jia Yen Lai ◽  
Lock Hei Ngu ◽  
Farouq Twaiq
Keyword(s):  
Ion Exchange ◽  
Ethanol Concentration ◽  
Nitrogen Adsorption ◽  
Crystalline Material ◽  
Hexadecyltrimethylammonium Bromide ◽  
Water Mixture ◽  
Extract Solution ◽  
Exchange Agent ◽  
Synthesis Solution ◽  
Mcm 41

Recycling of surfactant template for several subsequent MCM-41 synthesis is necessary to reduce substantial synthesis solution disposal. In MCM-41 synthesis, ethanol concentration and template ion exchange agent are two significant factors that affect the silicate polymerization, solvating effect on micelles formation, and MCM-41 mesostructure formation. In view of that, this study investigates recycling of surfactant template ions in extract solution in Mobil Crystalline Material 41 (MCM-41) synthesis. Effect of the ethanol concentrations in the solution gel and the types of ion exchange agents on the yield of MCM-41 material and its surface morphology were studied. Hexadecyltrimethylammonium bromide was used as template for MCM-41 synthesis using tetraethylorthosilicate (TEOS) as silica reagent with ethanol-water mixture as solvent at different ethanol concentrations. Template ions of synthesis gel was exchanged with an ion exchange agent (i.e., 1-butyl-3-methylimidazolium chloride or ammonium nitrate) before it is extracted using synthesis solution. After extraction, the extracting solution was added with TEOS, used for second synthesis cycle and the process continued in an extraction. The template ions in the extract solution were further recycled up to eight synthesis cycles. Yield of calcined materials significantly influenced by ethanol solvent concentrations and however did not vary with various ion exchange agents. Nitrogen adsorption isotherms showed that the calcined materials exhibit MCM-41 characteristics with surface areas ranging from 600 – 1000 m2/g. It is possible to recycle and reuse the surfactant template for several subsequent times of preparing MCM-41 if the ethanol concentration in the solution gel controlled continuously.

Effect of Thermal Radiation on an Unsteady Magnetohydrodynamic Double Diffusive Boundary Layer Flow past a Permeable Infinite Vertical Plate with Heat Source

2020 ◽  
pp. 122-134
Author(s):  
O. O. Kehinde ◽  
F. S. Akinboro ◽  
A. D. Adediipo
Keyword(s):  
Boundary Layer ◽  
Heat Source ◽  
Perturbation Technique ◽  
Source Parameters ◽  
Source Parameter ◽  
Radiation Parameter ◽  
Electrically Conducting ◽  
Increase With Increase ◽  
Layer Flow ◽  
Effects Of Radiation

In this paper, effect of radiation and heat source parameters on temperature, concentration and velocity profile of an electrically conducting fluid passing through an infinite permeable plate is investigated. The governing equation, which was based on the balanced mass, linear momentum, energy and species concentration, were non-dimensionalized to reduce the equations to system of ordinary differential equations. This was then solved by perturbation technique. Effects of radiation parameter, heat source parameter, and Schmidt parameter are analyzed. We observed that the velocity and concentration profiles increase with increase in radiation parameter and heat source parameter. The temperature profile increases with decrease in radiation parameter with increases boundary layer thickness.

Experimental Investigation and Optimization of Non-Catalytic In-Situ Biodiesel Production from Rice Bran Using Response Surface Methodology Historical Data Design

2021 ◽  
Vol 10 (4) ◽  
pp. 803-810
Author(s):  
Siti Zullaikah ◽  
Ari Krisna Putra ◽  
Fathi Haqqani Fachrudin ◽  
Rosada Y Naulina ◽  
Sri Utami ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Rice Bran ◽  
Historical Data ◽  
Ethanol Concentration ◽  
Operating Conditions ◽  
Biodiesel Production ◽  
Optimum Operating ◽  
Water Mixture ◽  
Data Design

Rice bran oil (RBO)is claimed to be a potential feedstock for biodiesel production. Non-catalytic in-situ biodiesel production from a low-cost feedstock (rice bran) using subcritical ethanol-water mixture was investigated in this study. The influence of four independent variables, i.e., addition of co-solvent, ethanol concentration, temperature, and time of reactions, on the yield of biodiesel was examined. The results showed that the most effective co-solvent wasethyl acetate and the optimum ethanol concentration, temperature and reaction time were 80% v/v, 200 oC and 3 hours, respectively. The maximum yield of biodiesel was found to be around 80%. The optimization of operating conditions was carried out by response surface methodology (RSM) with historical data design (HDD). The statistical method also suggested similar optimum operating conditions, i.e., 78.44% (v/v) ethanol concentration, 200 oC, and 3.2 hours reaction time with ethyl acetate as a co-solvent. The predicted maximum biodiesel yield was also slightly lower, i.e., 76.98%. Therefore, this study suggests that biodiesel production from rice bran through a non-catalytic in-situ process using a subcritical ethanol-water mixture with ethyl acetate as a co-solvent is very feasible since the yield can reach 80%. The study also found that RSM with HDD can predict the optimum operating conditions with a good accuracy.

Three-Dimensional Calculations of Evaporative Flow in Compressor Blade Rows

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
R. C. Payne ◽  
A. J. White
Keyword(s):  
Evaporation Rate ◽  
Three Dimensional ◽  
Droplet Evaporation ◽  
Compressor Blade ◽  
Computational Method ◽  
Water Mixture ◽  
Liquid Droplets ◽  
Two Phase ◽  
Physical Behavior ◽  
Eulerian Method

The present paper describes a three-dimensional computational method developed to solve the flow of a two-phase air-water mixture, including the effects of evaporation for a monodispersion of liquid droplets. The calculations employ a fully Eulerian method for the conservation of droplet number and liquid mass and are applicable to multiple blade rows, both stationary and rotating. The method is first tested to ensure that it computes the correct droplet evaporation rate and the correct physical behavior for evaporation within a 1D duct. Results are then presented for flow within a single compressor stage, i.e., a rotor-stator combination.

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