Development of the Rotating Liquid Sheet Contactor: Fundamental Studies and Modeling of Single Liquid Sheets from Slotted Tubes

2019 ◽  
Vol 58 (43) ◽  
pp. 20066-20080
Author(s):  
Yanyan Zhao ◽  
David J. Grillmeier ◽  
Christopher B. Solnordal ◽  
Clotilde C. Corsi ◽  
Leigh T. Wardhaugh
Keyword(s):  
Liquid Sheet ◽  
Liquid Sheets ◽  
Rotating Liquid

Nonlinear instability of plane liquid sheets

2000 ◽  
Vol 406 ◽  
pp. 281-308 ◽  
Author(s):  
SEYED A. JAZAYERI ◽  
XIANGUO LI
Keyword(s):  
Weber Number ◽  
Density Ratio ◽  
Perturbation Expansion ◽  
Liquid Sheet ◽  
Fundamental Wave ◽  
Liquid Density ◽  
Initial Amplitude ◽  
Nonlinear Stability Analysis ◽  
Liquid Sheets ◽  
Breakup Time

A nonlinear stability analysis has been carried out for plane liquid sheets moving in a gas medium at rest by a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter. The first, second and third order governing equations have been derived along with appropriate initial and boundary conditions which describe the characteristics of the fundamental, and the first and second harmonics. The results indicate that for an initially sinusoidal sinuous surface disturbance, the thinning and subsequent breakup of the liquid sheet is due to nonlinear effects with the generation of higher harmonics as well as feedback into the fundamental. In particular, the first harmonic of the fundamental sinuous mode is varicose, which causes the eventual breakup of the liquid sheet at the half-wavelength interval of the fundamental wave. The breakup time (or length) of the liquid sheet is calculated, and the effect of the various flow parameters is investigated. It is found that the breakup time (or length) is reduced by an increase in the initial amplitude of disturbance, the Weber number and the gas-to-liquid density ratio, and it becomes asymptotically insensitive to the variations of the Weber number and the density ratio when their values become very large. It is also found that the breakup time (or length) is a very weak function of the wavenumber unless it is close to the cut-off wavenumbers.

scholarly journals A Comprehensive Model to Predict Simplex Atomizer Performance

1998 ◽  
Author(s):  
Y. Liao ◽  
A. T. Sakman ◽  
S. M. Jeng ◽  
M. A. Jog ◽  
M. Benjamin
Keyword(s):  
Stability Analysis ◽  
Film Thickness ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Liquid Fuel ◽  
Density Ratio ◽  
Liquid Sheet ◽  
Unstable Wave ◽  
Liquid Sheets ◽  
Breakup Model

The performance of liquid fuel atomizer has direct effects on combustion efficiency, pollutant emission and stability. Pressure swirl atomizer, or simplex atomizer, is widely used in liquid fuel combustion devices in aircraft and power generation industry. A computational, experimental, and theoretical study is conducted to predict its performance. The Arbitrary-Lagrangian-Eulerian method with finite volume scheme is employed in the CFD model. Internal flow characteristics of the simplex atomizer as well as its performance parameters such as discharge coefficient, spray angle and film thickness are predicted. A temporal linear stability analysis is performed for cylindrical liquid sheets under 3-D disturbance. The model incorporates swirling velocity component, finite film thickness and radius which are essential features of conical liquid sheets emanating from simplex atomizers. It is observed that the relative velocity between liquid and gas phase, density ratio and surface curvature enhance the interfacial aerodynamic instability. As Weber number and density ratio increase, both the wave growth rate and the unstable wave number range increase. Combination of axial and swirling velocity components is more effective than single axial component for disintegration of liquid sheet. A breakup model for conical liquid sheet is proposed. Combining the breakup model with linear stability analysis, mean drop sizes are predicted. The theoretical results are compared with measurement data and agreement is very good.

Atomization of acoustically forced liquid sheets

2019 ◽  
Vol 880 ◽  
pp. 653-683 ◽  
Author(s):  
Sandip Dighe ◽  
Hrishikesh Gadgil
Keyword(s):  
Acoustic Field ◽  
Cutoff Frequency ◽  
Liquid Sheet ◽  
Liquid Jets ◽  
Liquid Sheets ◽  
Aerodynamic Interaction ◽  
Transverse Acoustic ◽  
External Acoustic Field ◽  
Acoustic Forcing ◽  
Sheet Breakup

Atomization of a smooth laminar liquid sheet produced by the oblique impingement of two liquid jets and subjected to transverse acoustic forcing in quiescent ambient is investigated. The acoustic forcing perturbs the liquid sheet perpendicular to its plane, thereby setting up a train of sinuous waves propagating radially outwards from the impingement point. These sheet undulations grow as the wave speed decreases towards the edge of the sheet and the sheet characteristics, like intact length and mean drop size, reduce drastically as compared to the natural breakup. Our observations show that the effect of the acoustic field is perceptible over a continuous range of forcing frequencies. Beyond a certain forcing frequency, called the cutoff frequency, the effect of the external acoustic field ceases. The cutoff frequency is found to be an increasing function of the Weber number. Our measurements of the characteristics of spatially amplifying sinuous waves show that the instabilities responsible for the natural sheet breakup augment in the presence of external forcing. Combining the experimental observations and measurements, we conclude that the linear theory of aerodynamic interaction (Squire’s theory) (Squire, Brit. J. Appl. Phys., vol. 4 (6), 1953, pp. 167–169) predicts the important features of this phenomenon reasonably well.

Liquid Sheet Breakup in Gas-Centered Swirl Coaxial Atomizers

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
V. Kulkarni ◽  
D. Sivakumar ◽  
C. Oommen ◽  
T. J. Tharakan
Keyword(s):  
Flow Behavior ◽  
Liquid Sheet ◽  
Liquid Sheets ◽  
Sheet Surface ◽  
Air Jet ◽  
Entrainment Process ◽  
Sheet Breakup ◽  
Experimental Fluids ◽  
Flow Experiments

The study deals with the breakup behavior of swirling liquid sheets discharging from gas-centered swirl coaxial atomizers with attention focused toward the understanding of the role of central gas jet on the liquid sheet breakup. Cold flow experiments on the liquid sheet breakup were carried out by employing custom fabricated gas-centered swirl coaxial atomizers using water and air as experimental fluids. Photographic techniques were employed to capture the flow behavior of liquid sheets at different flow conditions. Quantitative variation on the breakup length of the liquid sheet and spray width were obtained from the measurements deduced from the images of liquid sheets. The sheet breakup process is significantly influenced by the central air jet. It is observed that low inertia liquid sheets are more vulnerable to the presence of the central air jet and develop shorter breakup lengths at smaller values of the air jet Reynolds number Reg. High inertia liquid sheets ignore the presence of the central air jet at smaller values of Reg and eventually develop shorter breakup lengths at higher values of Reg. The experimental evidences suggest that the central air jet causes corrugations on the liquid sheet surface, which may be promoting the production of thick liquid ligaments from the sheet surface. The level of surface corrugations on the liquid sheet increases with increasing Reg. Qualitative analysis of experimental observations reveals that the entrainment process of air established between the inner surface of the liquid sheet and the central air jet is the primary trigger for the sheet breakup.

On the temporal instability of a two-dimensional viscous liquid sheet

1991 ◽  
Vol 226 ◽  
pp. 425-443 ◽  
Author(s):  
Xianguo Li ◽  
R. S. Tankin
Keyword(s):  
Growth Rate ◽  
Viscous Liquid ◽  
Local Maximum ◽  
Liquid Sheet ◽  
Rate Curve ◽  
Liquid Viscosity ◽  
Number Range ◽  
Liquid Sheets ◽  
Temporal Instability ◽  
Aerodynamic Instability

This paper reports a temporal instability analysis of a moving thin viscous liquid sheet in an inviscid gas medium. The results show that surface tension always opposes, while surrounding gas and relative velocity between the sheet and gas favour, the onset and development of instability. It is found that there exist two modes of instability for viscous liquid sheets – aerodynamic and viscosity-enhanced instability – in contrast to inviscid liquid sheets for which the only mode of instability is aerodynamic. It is also found that axisymmetrical disturbances control the instability process for small Weber numbers, while antisymmetrical disturbances dominate for large Weber numbers. For antisymmetrical disturbances, liquid viscosity, through the Ohnesorge number, enhances instability at small Weber numbers, while liquid viscosity reduces the growth rate and the dominant wavenumber at large Weber numbers. At the intermediate Weber-number range, Liquid viscosity has complicated effects due to the interaction of viscosity-enhanced and aerodynamic instabilities. In this range, the growth rate curve exhibits two local maxima, one corresponding to aerodynamic instability, for which liquid viscosity has a negligible effect, and the other due to viscosity-enhanced instability, which is influenced by the presence and variation of liquid viscosity. For axisymmetrical disturbances, liquid viscosity always reduces the growth rate and the dominant wavenumber, aerodynamic instability always prevails, and although the regime of viscosity-enhanced instability is always present, its growth rate curve does not possess a local maximum.

A photographic investigation into the disintegration of liquid sheets

1954 ◽  
Vol 247 (924) ◽  
pp. 101-130 ◽  
Keyword(s):  
Surface Tension ◽  
High Surface ◽  
Free Edge ◽  
High Viscosity ◽  
Liquid Sheet ◽  
Flow Rates ◽  
High Surface Tension ◽  
Liquid Sheets ◽  
Low Viscosity ◽  
Spinning Disk

The types of apparatus used to produce liquid sheets are classified according to the manner in which the energy is imparted to the liquid. The factors influencing the development, stability and manner of disintegration of a liquid sheet are examined more particularly with flat sheets produced from the single-hole fan-spray nozzle and the spinning disk. The development of the liquid sheet is influenced by the liquid properties. As the working pressure is raised the width of the sheet increases, but this development is hindered by high surface tension. It is shown that the effect of a surface-active agent on the development is only influential where the surface is not expanding or changing rapidly. Consequently its effect is more pronounced as the liquid moves farther away from the orifice. Increase of viscosity at the same pressure causes the region of disintegration to move away from the orifice, and high viscosity maintains the sheet undisturbed by air friction. Density has little effect on the area of the sheet. The effect of turbulence in the orifice is shown to be responsible for at least two types of disturbance in the sheet which results in holes being formed near the orifice. The depth of the disturbance in the sheet has to be equal to the thickness before disruption occurs. Similar disruption through the formation of holes can be caused by suspensions of unwettable particles. Wettable particles in low concentration, irrespective of their size, have no effect on the manner of disintegration. The most placid, stable and resistant sheet is obtained with a liquid of high surface tension, high viscosity, low density, giving low turbulence in the nozzle. Such a sheet will disintegrate when the velocity is raised and disintegration can occur through air friction. The easiest sheet to disintegrate is obtained with a liquid of low surface tension, low viscosity, low density and with low turbulence in the nozzle. Disintegration will occur near the nozzle at low velocities through waves caused by air friction. Disintegration through the formation of holes in the sheet can occur at low velocity with liquids of high surface-tension, low viscosity and high density where turbulence obtains in the nozzle. The formation of ligaments or threads is a necessary stage before the production of drops. Threads can be formed directly from any free edge or in the boundary. A free edge is formed when equilibrium exists between surface tension and inertia forces. In the spinning disk, at low flow rates, where the sheet is in contact with the surface of the disk, drops are formed at the ends of threads which break down into a limited number of sizes. At high flow rates a free edge of liquid exists outside the periphery of the disk with the formation of more irregular threads and a wider spectrum of drop sizes results. Where perforations occur in the sheet, expansion of the hole by surface tension occurs very regularly so that the holes remain nearly circular until they coalesce forming long threads. These long threads quickly become unstable and break down into drops. Threads being approximately uniform in diameter produce uniform drops, but the irregular areas of liquid which occur when a number of holes expand towards each other produce a wide variety of drop sizes. When the velocity of the sheet in the atmosphere is high, air friction causes slight variations in the sheet to develop rapidly into major wave disturbances, and these can result in holes being blown through the sheet so that disruption starts before the formation of a leading edge. With liquids having visco-elastic properties the sheet disintegrates through the formation of waves, but the rapid increase of viscosity, as the rate of shear is reduced, prevents further break-up of the threads into drops and a web of fine threads only is produced.

Break-Up Length and Spreading Angle of Liquid Sheets Formed by Splash Plate Nozzles

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
M. Ahmed ◽  
N. Ashgriz ◽  
H. N. Tran
Keyword(s):  
Experimental Investigation ◽  
Flow Velocity ◽  
Liquid Sheet ◽  
Operating Conditions ◽  
Nozzle Diameter ◽  
Empirical Correlation ◽  
Liquid Viscosity ◽  
Liquid Sheets ◽  
Break Up ◽  
Semi Empirical

An experimental investigation is conducted to determine the effect of liquid viscosity and density, nozzle diameter, and flow velocity on the break-up length and spreading angle of liquid sheets formed by splash plate nozzles. Various mixtures of corn syrup and water were used to obtain viscosities in the range of 1–170 mPa s. Four different splash plate nozzle diameters of 0.5 mm, 0.75 mm, 1 mm, and 2 mm, with a constant plate angle of 55 deg were tested. The liquid sheet angles and the break-up lengths were measured at various operating conditions. An empirical correlation for the sheet spreading angle and a semi-empirical correlation for the sheet break-up lengths are developed.

CO2 separation by rotating liquid sheet contactor: A novel procedure to improve mass transfer characterization

2021 ◽  
Author(s):  
Morteza Mehdipour ◽  
Abbas Elhambakhsh ◽  
Peyman Keshavarz ◽  
Mohammad Reza Rahimpour ◽  
Yasha Hasanzadeh
Keyword(s):  
Mass Transfer ◽  
Liquid Sheet ◽  
Co2 Separation ◽  
Rotating Liquid ◽  
Improve Mass Transfer

Breakup Model for Annular Liquid Sheets

2006 ◽  
Author(s):  
Ashraf A. Ibrahim ◽  
Milind A. Jog
Keyword(s):  
Fuel Injection ◽  
Surface Deformation ◽  
Perturbation Expansion ◽  
Perturbation Parameter ◽  
Liquid Sheet ◽  
Gas Streams ◽  
Liquid Sheets ◽  
Expansion Technique ◽  
Axially Moving ◽  
Breakup Model

The instability and breakup of annular liquid sheet is encountered in liquid atomization process used in numerous applications including liquid fuel injection in combustion engines and spray drying of foods. A nonlinear breakup model for annular liquid sheet exposed to both inner and outer air streams by a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter has been developed. The liquid sheet moves at a uniform axial velocity and subjects to axially moving inner and outer gas streams. The temporal evolution of the dimensionless surface deformation at the inner and outer liquid-gas interface has been evaluated until the point of breakup. The breakup length predictions show good agreement with the available experimental data.

Life of a smooth liquid sheet

2002 ◽  
Vol 462 ◽  
pp. 307-340 ◽  
Author(s):  
CHRISTOPHE CLANET ◽  
EMMANUEL VILLERMAUX
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Stationary Regime ◽  
Liquid Sheet ◽  
Liquid Sheets ◽  
Small Disc ◽  
High Reynolds ◽  
The Impact

We report on experiments with liquid sheets formed through the impact of a slender jet on a small disc at high Reynolds number. When the interaction with the surrounding air is negligible, the sheet spreads out radially and remains smooth. The study extends over the whole life of the sheet, considering the dynamics of its formation and destruction and paying special attention to the stationary regime, in which the transition from sheet to drops occurs.

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