Management of Flow of Cleaning Solvents to Wet Surfaces (The Wettability Index and the Dimensionless Ohnesorge Number)

2014 ◽  
pp. 529-543
Keyword(s):  
Ohnesorge Number ◽  
Cleaning Solvents

scholarly journals Dynamics of retracting surfactant-laden ligaments at intermediate Ohnesorge number

2020 ◽  
Vol 5 (8) ◽  
Author(s):  
Cristian R. Constante-Amores ◽  
Lyes Kahouadji ◽  
Assen Batchvarov ◽  
Seungwon Shin ◽  
Jalel Chergui ◽  
...  
Keyword(s):  
Ohnesorge Number

Generation of secondary droplets in coalescence of a drop at a liquid–liquid interface

2010 ◽  
Vol 655 ◽  
pp. 72-104 ◽  
Author(s):  
B. RAY ◽  
G. BISWAS ◽  
A. SHARMA
Keyword(s):  
Critical Value ◽  
Bond Number ◽  
Viscous Force ◽  
Time Range ◽  
Main Body ◽  
Ohnesorge Number ◽  
Partial Coalescence ◽  
Daughter Droplets ◽  
Secondary Droplets ◽  
Secondary Drop

When a droplet of liquid 1 falls through liquid 2 to eventually hit the liquid 2–liquid 1 interface, its initial impact on the interface can produce daughter droplets of liquid 1. In some cases, a partial coalescence cascade governed by self-similar capillary-inertial dynamics is observed, where the fall of the secondary droplets in turn continues to produce further daughter droplets. Results show that inertia and interfacial surface tension forces largely govern the process of partial coalescence. The partial coalescence is suppressed by the viscous force when Ohnesorge number is below a critical value and also by gravity force when Bond number exceeds a critical value. Generation of secondary drop is observed for systems of lower Ohnesorge number for liquid 1, lower and intermediate Ohnesorge number for liquid 2 and for low and intermediate values of Bond number. Whenever the horizontal momentum in the liquid column is more than the vertical momentum, secondary drop is formed. A transition regime from partial to complete coalescence is obtained when the neck radius oscillates twice. In this regime, the main body of the column can be fitted to power-law scaling model within a specific time range. We investigated the conditions and the outcome of these coalescence events based on numerical simulations using a coupled level set and volume of fluid method (CLSVOF).

scholarly journals Study on cleaning solvents using activated alumina in PUREX process

2011 ◽  
Vol 1 (1) ◽  
pp. 71-74
Author(s):  
Y. Arai ◽  
H. Ogino ◽  
M. Takeuchi ◽  
T. Kase ◽  
Y. Nakajima
Keyword(s):  
Phase Separation ◽  
Tributyl Phosphate ◽  
Spent Nuclear Fuel ◽  
Degradation Products ◽  
Purex Process ◽  
Separation Performance ◽  
Activated Alumina ◽  
Alkali Solutions ◽  
Cleaning Solvents ◽  
Separation Test

Abstract The PUREX process is used to extract uranium and plutonium from dissolved solutions (spent nuclear fuel liquor). The extractant is 30% tributyl phosphate in n-dodecane, which is known to be degradable by radiation and nitric acid. Tributyl phosphate degradation products can generally be washed in alkali solutions like sodium carbonate solution; however, it is more difficult to remove n-dodecane degradation products using this method. A method of cleaning solvents using activated alumina is discussed in this study. A degradation sample of 30% TBP/n-dodecane was prepared by irradiating (1.6 MGy) with a 60Co gamma-source. The degradation products were then qualitatively analyzed using a gas chromatography-mass spectrometer (GC-MS). After being irradiated the solvents were cleaned with activated alumina, and a phase separation test with performed in evaluating the cleaned solvent. This resulted in the discovery of a procedure for the removal of n-dodecane degradation products of dodecanol and dodecanone, with about 70% of the degradation products, and the phase separation performance could be clearly improved through use of activated alumina.

Effects of Non-Dimensional Parameters on Formation and Break Up of Cylindrical Droplets

2004 ◽  
Author(s):  
Mohammad Taeibi-Rahni ◽  
Shervin Sharafatmand
Keyword(s):  
Stokes Equations ◽  
Fluid Model ◽  
Time Dependent ◽  
Navier Stokes ◽  
Ohnesorge Number ◽  
Viscous Effects ◽  
Navier Stokes Equations ◽  
Dimensional Parameters ◽  
Break Up ◽  
Eotvos Number

The consistent behavior of non-dimensional parameters on the formation and break up of large cylindrical droplets has been studied by direct numerical simulations (DNS). A one-fluid model with a finite difference method and an advanced front tracking scheme was employed to solve unsteady, incompressible, viscous, immiscible, multi-fluid, two-dimensional Navier-Stokes equations. This time dependent study allows investigation of evolution of the droplets in different cases. For moderate values of Atwood number (AT), increasing Eotvos number (Eo) explicitly increases the deformation rate in both phenomena. Otherwise, raising the Ohnesorge number (Oh) basically amplifies the viscous effects.

Refractive index matched visualization and particle image velocimetry measurements of initial breakup of turbulent oil jet

2017 ◽  
Vol 2017 (1) ◽  
pp. 2017328
Author(s):  
Xinzhi Xue ◽  
Joseph Katz
Keyword(s):  
Reynolds Number ◽  
Crude Oil ◽  
High Speed ◽  
Particle Image ◽  
Silicone Oil ◽  
Water Solution ◽  
Ohnesorge Number ◽  
Sugar Water ◽  
Image Velocimetry ◽  
Oil Jet

Subsurface oil well blowouts create buoyant, immiscible jets and plumes. Turbulent breaks jets into oil droplets with sizes ranging from several millimeters to sub-microns. The fate of oil droplets largely depends on their sizes. The physics of single thread of fluid breaks into several smaller droplets in low Reynolds number and Ohnesorge number can be well explained by Plateau-Rayleigh instability. However, when Reynolds number and Ohnesorge number are high, namely the atomization regime, the physics of high-speed jet fragments into a wide range of droplets is not well understood. Because of the opaque nature of crude oil, it is difficult to visualize and optically quantify the process of initial jet breakup and droplet generation within the zone of flow establishment (less than 10 nozzle diameters downstream). In order to overcome this issue, in this experimental study, two immiscible fluids (silicone oil, 64% v/v sugar water solution) with a matching index of refraction of nD=1.4015 are used as surrogates of crude oil and seawater. High speed visualization and particle image velocimetry (PIV) are implemented to study vertical turbulent oil jets of varying Reynolds and Ohnesorge numbers, all falling in the atomization range. The refractive index match enables light to pass through the test sample region with little refraction, thus providing undistorted images for flow visualization and quantitative measurements. The kinematic viscosity ratio voil/vaq = 5.64, density ratio ρoil/ρaq = 0.83, and interfacial tension σ = 28.8 mN/m between silicone oil and sugar water solution are closely matched with those of crude oil and seawater. Entrainment of the aqueous phase by the high speed oil jet can be clearly shown by PIV. Using fluorescent dye in the oil phase, jet fragmentation morphology can be captured simultaneously with PIV images.

STUDY ON ELECTROHYDRODYNAMIC CAPILLARY INSTABILITY OF VISCOELASTIC FLUIDS IN PRESENCE OF AXIAL ELECTRIC FIELD

2012 ◽  
Vol 04 (03) ◽  
pp. 1250027 ◽  
Author(s):  
D. K. TIWARI ◽  
MUKESH KUMAR AWASTHI ◽  
G. S. AGRAWAL
Keyword(s):  
Electric Field ◽  
Flow Analysis ◽  
Critical Value ◽  
Deborah Number ◽  
Wave Number ◽  
Conductivity Ratio ◽  
Ohnesorge Number ◽  
Capillary Instability ◽  
Axial Electric Field ◽  
Linear Viscoelastic

Linear viscoelastic potential flow analysis of capillary instability in presence of axial electric field has been studied. A dispersion relation is derived for the case of axially imposed electric field and stability is discussed in terms of various parameters such as electric field, Deborah number, Ohnesorge number, permittivity ratio and conductivity ratio etc. Stability criterion is given in the terms of critical value of wave number as well as critical value of applied electric field. The system is unstable when electric field is less than the critical value of electric field, otherwise it is stable. It has been found that in presence of the electric field the growth rates for viscoelastic fluid are higher than viscous fluid. Various graphs have been plotted for growth rate and critical electric field.

Sign in / Sign up

Export Citation Format

Share Document