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.

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.

Atomization of undulating liquid sheets

2007 ◽  
Vol 585 ◽  
pp. 421-456 ◽  
Author(s):  
N. BREMOND ◽  
C. CLANET ◽  
E. VILLERMAUX
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Free Edge ◽  
Liquid Sheet ◽  
Drop Size Distribution ◽  
Secondary Instability ◽  
Operating Conditions ◽  
Helmholtz Instability ◽  
Liquid Sheets ◽  
Unique Parameter

The fragmentation of a laminar undulating liquid sheet flowing in quiescent air is investigated. Combining various observations and measurements we propose a sequential atomization scenario describing the overall sheet–drop transition in this configuration. The undulation results from a controlled primary Kelvin–Helmholtz instability. As the liquid travels through the undulating pattern, it experiences transient accelerations perpendicular to the sheet. These accelerations trigger a secondary instability responsible for the amplification of spanwise thickness modulations of the sheet. This mechanism, called the ‘wavy corridor’, is responsible for the sheet free edge indentations from which liquid ligaments emerge and break, forming drops. The final drop size distribution is of a Gamma type characterized by a unique parameter independent of the operating conditions once drop sizes are normalized by their mean.

The break-up of axisymmetric liquid sheets

1970 ◽  
Vol 43 (2) ◽  
pp. 305-319 ◽  
Author(s):  
J. C. P. Huang
Keyword(s):  
Wave Motion ◽  
Wave Speed ◽  
Empirical Equation ◽  
Wave Pattern ◽  
Rayleigh Instability ◽  
Number Range ◽  
Liquid Sheets ◽  
Vibrating Membrane ◽  
Break Up ◽  
Semi Empirical

The break-up mechanism of axisymmetric liquid sheets formed by the impingement of two co-axial jets has been examined. Three break-up regimes in the Weber number range from 100 to 3 × 104 are reported. In the first break-up regime, droplets are formed through successive mergings of liquid beads along the nearly circular periphery of the sheet. The formation of beads is caused by Rayleigh instability. In the transition regime, Taylor's cardioid wave pattern prevails in the first half of this regime, while the sheet begins to flap in the second half.In the second break-up regime, antisymmetric waves on the sheet grow radially. A semi-empirical equation has been deduced to predict the break-up radius of the sheet. The motion of an axisymmetric vibrating membrane with radially decreasing thickness has been studied to include Helmholtz instability as an analogue of the wave motion of the expanding circular sheet. A distorted progressive wave equation has been solved by the WKBJ method to indicate the effect of cylindrical geometry. The calculated wave speed agrees fairly well with experimental data at low Weber numbers.

Experimental investigation of nonlinear instabilities in annular liquid sheets

2012 ◽  
Vol 691 ◽  
pp. 594-604 ◽  
Author(s):  
D. Duke ◽  
D. Honnery ◽  
J. Soria
Keyword(s):  
Experimental Investigation ◽  
Shear Layer ◽  
Hilbert Transform ◽  
Liquid Sheet ◽  
Nonlinear Instability ◽  
Shear Layer Instability ◽  
Free Shear Layer ◽  
Liquid Sheets ◽  
The Hilbert Transform

AbstractThe aerodynamically driven annular liquid sheet exhibits a complex nonlinear instability. Novel interfacial velocimetry experiments suggest that two distinct physical sources of instability may be present. The first is the well-known free shear layer instability, which is quasi-sinusoidal and nonlinear. The second is a distinct nonlinear rupturing instability, modulated on the previous one. It may be directly driving primary atomization. This instability has not been previously observed in isolation and is inherently nonlinear and non-sinusoidal. Novel application of Koopman analysis and the Hilbert transform permit investigation of these distinct instabilities. A greater understanding of the rupturing instability may lead to a better understanding of atomization phenomena.

A Modified Semi-Empirical Correlation for Designing Two-Phase Separators

2021 ◽  
pp. 108782
Author(s):  
Mehdi Fadaei ◽  
M.J. Ameri ◽  
Y. Rafiei ◽  
Kayvan Ghorbanpour
Keyword(s):  
Empirical Correlation ◽  
Two Phase ◽  
Semi Empirical
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