Planar liquid sheets surrounded by another immiscible liquid at low capillary Reynolds numbers

2021 ◽  
Vol 33 (11) ◽  
pp. 112103
Author(s):  
Claudiu Patrascu ◽  
Corneliu Balan
Keyword(s):  
Reynolds Numbers ◽  
Immiscible Liquid ◽  
Liquid Sheets

Parametric Analysis of Microdroplet Formation in Co-Axial Co-Flowing Immiscible Liquids in Microtubes

2011 ◽  
Author(s):  
In-Hwan Yang ◽  
Mohamed S. El-Genk
Keyword(s):  
Finite Element Method ◽  
Surface Tension ◽  
Parametric Analysis ◽  
Jump Condition ◽  
Reynolds Numbers ◽  
Immiscible Liquid ◽  
Liquid Droplets ◽  
Immiscible Liquids ◽  
Interfacial Surface ◽  
Disperse Liquid

This paper presents numerical results of disperse liquid droplets forming in the dripping regime at the tip of a microtube into another co-flowing immiscible liquid in a coaxial microtube of larger diameter. Investigated are the effects of the interfacial surface tension, velocities and viscosities of the liquids and the diameters of the coaxial microtubes on the forming dynamics and the size of the droplet. The 2-D, transient Navier-Stockes equations, in conjunction with the momentum jump condition across the interface between the co-flowing liquids are solved using a finite element method. The solution tracks the interface and the growth of the droplet and predicts droplet size and forming frequency. The droplet’s dimensionless radius (rd*) is correlated within ± 10% in terms of the continuous liquid capillary number (Cac) and ratios of Reynolds numbers (Red/Rec) and microtube radii (Rc/Rd) of the co-flowing liquids as: rd*=0.225R*0.466/(Cac0.5)(Red/Rec).0.05

Passive Microextractor with Internal Fluid Recirculation for Two Immiscible Liquids

2014 ◽  
Vol 12 (1) ◽  
pp. 285-293 ◽  
Author(s):  
Cong Xu ◽  
Jiao Wang
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Molecular Diffusion ◽  
Reynolds Numbers ◽  
Immiscible Liquid ◽  
Chaotic Advection ◽  
Inlet Channel ◽  
External Energy ◽  
Outlet Channel ◽  
Internal Fluid

Abstract A microextractor comprising an inlet channel, a mixing chamber, two feedback channels, and an outlet channel and having no moving parts was designed for immiscible liquid–liquid extraction. Two liquids were mixed passively without any external energy input, and the extraction was completed in the microextractor. The extractor performance with or without a splitter was investigated by visualization and mass transfer experiments. Two mixing mechanisms were observed: (i) molecular diffusion at lower Reynolds number and (ii) chaotic advection at higher Reynolds number. The transition point between the two mechanisms was at Reynolds numbers 375.2 and 179.9 for the aqueous phase (3 mol/L HNO3 solution) and the organic phase (30% tributyl phosphate (TBP)–kerosene solution), respectively. In the chaotic advection mode, two vortexes rotating in opposite directions were formed on both sides of the main flow, which enhanced the mass transfer between the two liquids. Mass transfer between the 3 mol/L HNO3 and 30% TBP–kerosene solutions was achieved with an efficiency of 92.8% at the extractor exit when the extractor operated in the chaotic advection mode.

TRANSITION RANGES FOR THREE-DIMENSIONAL WAKES

1961 ◽  
Vol 39 (10) ◽  
pp. 1418-1422 ◽  
Author(s):  
R. H. Magarvey ◽  
Roy L. Bishop
Keyword(s):  
Three Dimensional ◽  
Reynolds Numbers ◽  
Immiscible Liquid ◽  
Physical Characteristics ◽  
Liquid Systems ◽  
Wake Patterns ◽  
Set Up

The motions set up in a liquid due to the passage of a drop of an immiscible liquid have been examined for a number of liquid–liquid systems. Wake configurations corresponding to Reynolds numbers between 0 and 2500 have been photographed, and the transition ranges between the various wake configurations have been determined. Several liquid–liquid systems were used in obtaining data on wake patterns, and it was found that identical patterns correspond to approximately the same Reynolds numbers regardless of the system. However, the exact transition number cannot be determined for the general case as drop deformations depend on the physical characteristics of a particular system. The range of Reynolds numbers corresponding to a transition from one wake pattern to another is somewhat less than 20.

Investigation on the effect of leading edge tubercles of sweptback wing at low reynolds number

2020 ◽  
Vol 21 (6) ◽  
pp. 621
Author(s):  
Veerapathiran Thangaraj Gopinathan ◽  
John Bruce Ralphin Rose ◽  
Mohanram Surya
Keyword(s):  
Leading Edge ◽  
Reynolds Numbers ◽  
Sweep Angle ◽  
Laminar Separation ◽  
Low Reynolds Numbers ◽  
Flow Energy ◽  
Airplane Wing ◽  
Low Reynolds ◽  
Naca 0015 ◽  
Wing Performance

Aerodynamic efficiency of an airplane wing can be improved either by increasing its lift generation tendency or by reducing the drag. Recently, Bio-inspired designs have been received greater attention for the geometric modifications of airplane wings. One of the bio-inspired designs contains sinusoidal Humpback Whale (HW) tubercles, i.e., protuberances exist at the wing leading edge (LE). The tubercles have excellent flow control characteristics at low Reynolds numbers. The present work describes about the effect of tubercles on swept back wing performance at various Angle of Attack (AoA). NACA 0015 and NACA 4415 airfoils are used for swept back wing design with sweep angle about 30°. The modified wings (HUMP 0015 A, HUMP 0015 B, HUMP 4415 A, HUMP 4415 B) are designed with two amplitude to wavelength ratios (η) of 0.1 & 0.24 for the performance analysis. It is a novel effort to analyze the tubercle vortices along the span that induce additional flow energy especially, behind the tubercles peak and trough region. Subsequently, Co-efficient of Lift (CL), Co-efficient of Drag (CD) and boundary layer pressure gradients also predicted for modified and baseline (smooth LE) models in the pre & post-stall regimes. It was observed that the tubercles increase the performance of swept back wings by the enhanced CL/CD ratio in the pre-stall AoA region. Interestingly, the flow separation region behind the centerline of tubercles and formation of Laminar Separation Bubbles (LSB) were asymmetric because of the sweep.

Low Reynolds number flow around and heat transfer from a heated circular cylinder

2010 ◽  
Vol 1 (1-2) ◽  
pp. 15-20 ◽  
Author(s):  
B. Bolló
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Reynolds Number Flow ◽  
Two Dimensional Flow ◽  
Number Flow ◽  
Low Reynolds ◽  
Increasing Temperature

Abstract The two-dimensional flow around a stationary heated circular cylinder at low Reynolds numbers of 50 < Re < 210 is investigated numerically using the FLUENT commercial software package. The dimensionless vortex shedding frequency (St) reduces with increasing temperature at a given Reynolds number. The effective temperature concept was used and St-Re data were successfully transformed to the St-Reeff curve. Comparisons include root-mean-square values of the lift coefficient and Nusselt number. The results agree well with available data in the literature.

ON THE STABILITY OF LIQUID SHEETS IN HOT ATMOSPHERES

1998 ◽  
Vol 8 (2) ◽  
pp. 235-240 ◽  
Author(s):  
E. A. Foumeny ◽  
N. Dombrowski
Keyword(s):  
Liquid Sheets ◽  
The Stability
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