scholarly journals Numerical Modelling of Liquid Film Spreading Dynamics over Smooth Vertical Surface under Isothermal Conditions

2021 ◽  
Vol 2119 (1) ◽  
pp. 012054
Author(s):  
A Sakhnov ◽  
O A Volodin ◽  
N I Pecherkin ◽  
A N Pavlenko
Keyword(s):  
Numerical Modelling ◽  
Liquid Film ◽  
Vertical Cylinder ◽  
Vertical Surface ◽  
Contact Angles ◽  
Wetting Front ◽  
Outer Flow ◽  
Spreading Dynamics ◽  
Flat Shape ◽  
Film Spreading

Abstract The paper presents numerical modelling of the liquid film spreading dynamics of the R21 (mol. fraction: 0.9) and R114 refrigerants mixture. We considered an outer flow along a round vertical cylinder at Reynolds number of 104 and various contact angles. The simulation was performed in OpenFOAM software on the basis of the volume of fluid (VOF) method. We have shown that the wetting front deforms at wetting angles of 30 and 50 degrees, and regular jets form. At the same time, it was demonstrated that at the wetting angle of 10 degrees the spreading front has practically a flat shape, but one may see some regular thickenings of the liquid film along the contact line of the front.

Liquid film spreading on a vertical surface

1978 ◽  
Vol 15 (1) ◽  
pp. 16-18
Author(s):  
S. Fabre ◽  
A. Ponter ◽  
W. Feier
Keyword(s):  
Liquid Film ◽  
Vertical Surface ◽  
Film Spreading

Effect Of The Rib Inclination Angle On Liquid Film Spreading Over The Structured Surface

2015 ◽  
Vol 10 (1) ◽  
pp. 42-49
Author(s):  
Aleksandr Pavlenko ◽  
Oleg Volodin ◽  
Vladimir Serdyukov
Keyword(s):  
Liquid Film ◽  
Flow Rate ◽  
Inclination Angle ◽  
High Speed ◽  
Film Flow ◽  
Complex Geometry ◽  
Experimental Studies ◽  
Local Flow ◽  
Structured Packing ◽  
Film Spreading

Results of experimental studies on hydrodynamics of the film flow of liquid nitrogen over the surface of the single elements of structured packing are presented. The effect of inclination angle of the large ribs and perforation on the zones of liquid film spreading over the corrugated surface with microtexture at different Reynolds numbers of the film is shown based on a comparison of experimental data. It is shown that the angle of large rib inclination has a significant influence on redistribution of the local flow rate of liquid flowing on the surface with complex geometry. Analysis of results of the high-speed video revealed that in a vicinity of the vertical lateral edges of corrugated plates, the intense rivulet flows are formed, including those with separation from the film flow surface. This negative factor can lead to significant liquid accumulation and flow near the vertical edges of the structured packing and on the inner wall of the heat exchanging apparatuses and, finally, to a significant increase in the degree of maldistribution of local liquid flow rate over the crosssection, for instance, of the distillation columns.

STABILITY ANALYSIS OF THE THIN POWER LAW LIQUID FILM FLOWING DOWN ON A VERTICAL CYLINDER

2006 ◽  
Vol 30 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Po-Jen Cheng ◽  
Kuo-Chi Liu
Keyword(s):  
Liquid Film ◽  
Power Law ◽  
Film Flow ◽  
Vertical Cylinder ◽  
Flow Index ◽  
Free Film ◽  
Long Wave ◽  
Lateral Curvature ◽  
The Stability ◽  
Film Interface

The paper investigates the stability theory of a thin power law liquid film flowing down along the outside surface of a vertical cylinder. The long-wave perturbation method is employed to solve for generalized linear kinematic equations with free film interface. The normal mode approach is used to compute the stability solution for the film flow. The degree of instability in the film flow is further intensified by the lateral curvature of cylinder. This is somewhat different from that of the planar flow. The analysis results also indicate that by increasing the flow index and increasing the radius of the cylinder the film flow can become relatively more stable as traveling down along the vertical cylinder.

scholarly journals Spreading and oscillation dynamics of drop impacting liquid film

2019 ◽  
Vol 881 ◽  
pp. 859-871 ◽  
Author(s):  
Xiaoyu Tang ◽  
Abhishek Saha ◽  
Chao Sun ◽  
Chung K. Law
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Liquid Surface ◽  
Strong Dependence ◽  
Solid Substrate ◽  
Spreading Dynamics ◽  
Viscous Loss ◽  
Shape Oscillation ◽  
Oscillation Dynamics ◽  
The Impact

We herein report an experimental study to explore the effects of impact inertia, film thickness and viscosity on the dynamics of shape deformation of a drop impacting a liquid film. We have identified that the spreading dynamics shows a weak dependence on impact inertia, but strongly depends on the film thickness. For a thick film, the liquid surface deforms and absorbs part of the impact energy, and hence inhibits spreading of the drop. For a thin film, the drop motion is restricted by the bottom solid substrate, promoting spreading. The periodicity of the capillary controlled shape oscillation, on the other hand, is found to be independent of impact inertia and film thickness. The damping of the shape oscillation shows strong dependence on the film thickness, in that the oscillation decays faster for smaller film thicknesses, due to the enhanced viscous loss.

Laminar Film Condensation From a Steam-Air Mixture Undergoing Forced Flow Down a Vertical Surface

1971 ◽  
Vol 93 (3) ◽  
pp. 297-304 ◽  
Author(s):  
V. E. Denny ◽  
A. F. Mills ◽  
V. J. Jusionis
Keyword(s):  
Liquid Film ◽  
Numerical Solution ◽  
Finite Difference Methods ◽  
Vertical Surface ◽  
Forced Flow ◽  
Film Condensation ◽  
Two Phase ◽  
Noncondensable Gas ◽  
Laminar Film ◽  
Laminar Film Condensation

An analytical study of the effects of noncondensable gas on laminar film condensation of vapor under going forced flow along a vertical surface is presented. Due to the markedly nonsimilar character of the coupled two-phase-flow problem, the set of parabolic equations governing conservation of momentum, species, and energy in the vapor phase was solved by means of finite-difference methods using a forward marching technique. Interfacial boundary conditions for the numerical solution were extracted from a locally valid Nusselt-type analysis of the liquid-film behavior. Locally variable properties in the liquid were treated by means of the reference-temperature concept, while those in the vapor were treated exactly. Closure of the numerical solution at each step was effected by satisfying overall mass and energy balances on the liquid film. A general computer program for solving the problem has been developed and is applied here to condensation from water-vapor–air mixtures. Heat-transfer results, in the form q/qNu versus x, are reported for vapor velocities in the range 0.1 to 10.0 fps with the mass fraction of air ranging from 0.001 to 0.1. The temperature in the free stream is in the range 100–212 deg F, with overall temperature differences ranging from 5 to 40 deg F. The influence of noncondensable gas is most marked for low vapor velocities and large gas concentrations. The nonsimilar character of the problem is especially evident near x = 0, where the connective behavior of the vapor boundary layer is highly position-dependent.

Theoretical and Experimental Analysis of Turbulent Liquid Film Flowing down a Vertical Surface

2009 ◽  
Vol 15 ◽  
pp. 3-8
Author(s):  
Stasys Sinkunas ◽  
Jonas Gylys ◽  
Algimantas Kiela
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Analytical Study ◽  
Film Flow ◽  
Convex Surface ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Vertical Surface ◽  
Momentum And Heat Transfer ◽  
Liquid Film Flow

The purpose of the present study is to obtain a comprehension for the momentum and heat transfer developments in gravitational liquid film flow. Analytical study of stabilized heat transfer for turbulent film was performed. A calculation method of the local heat transfer coefficient for a turbulent film falling down a vertical convex surface was proposed. The dependence of heat flux variation upon the distance from the wetted surface has been established analytically. Experimental study of velocity profiles for turbulent liquid film flow in the entrance region is performed as well. Analysis of profiles allowed estimating the length of stabilization for turbulent film flow under different initial velocities.

scholarly journals Numerical modelling of interactions of waves and sheared currents with a surface piercing vertical cylinder

2019 ◽  
Vol 145 ◽  
pp. 65-83 ◽  
Author(s):  
L.F. Chen ◽  
D. Stagonas ◽  
H. Santo ◽  
E.V. Buldakov ◽  
R.R. Simons ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Vertical Cylinder
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