SPH Simulation of Liquid Droplet Behavior on a Water ... Simulation of Liquid Droplet Behavior on a...
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SPH Simulation of Liquid Droplet Behavior on a Water-repellent Surface Masumi Ito 2013 The wetting property of a Liquid-Solid surface is represented by the angle which is made at the end of liquid body. Wettability and Contact Angle Liquid Cohesion (Surface tension) Algorithm SPH Comparison of wettability Rebound motion (Hydrophobic case) A liquid sphere falls and collides with solid surface (colliding velocity:0.85m/s) The effect of surface tension is given as a attractive force between particles Mass distribution of an SPH particle r (:distance from the center) Objective: To confirm Liquid-Solid contact can be properly computed using SPH method. Surface particle Inside particle The droplet collapsed. And then…… Γ S Γ S SL Γ Γ Liquid Air Solid : cos S SL Equilibrium Condition ← Please also refer to the experimental research with the same condition, Figure 4 in the paper “Spread and Rebound of Liquid Dropltes upon Impact on Flat Surafaces”, Ted Mao et al., AIChE Journal, (1997) Vol. 43, No. 9, pp. 2169-2179. 0 100 200 300 0 0.5 1 r/R Density (kg/m^3) 0 means hydrophilic , hydrophobic 180 Back Ground The treatment of wettability is important to calculate a fluid motion of a liquid body that touches a solid surface. For example, the bouncing behavior of a liquid droplet is largely changes with wettability which is seen in heat- exchanger tubes, where it is demanded to understand and suppress this phenomena. This study tries to compute this bouncing phenomena using a particle method (SPH). The effect of liquid cohesion was given as the attraction of particles. Investigated whether the SPH can properly calculate the geometry of the deforming liquid surface or not. Deforming behavior changes with wettability. R (:Influence radius) Conclusion: The SPH method is feasible to compute the liquid bouncing phenomena. *Opposing vectors are canceled. ab a hC F C h, , : Surface tension coefficient, Particle diameter, Arbitrary constant (includes weighting function) Results Surface geometry agreed with experiment well for each instant. hC F liq liq hC S F sol liq 2 / ) cos 1 ( as defined ratio, Wetting : S S Treatment of Wettability. Hydrophobicθ=97° Droplet bounce-up and leaves wall Hydrophilic θ=45° No bouncing motion Solid particle Particles move based on NS equation and represent a fluid motion
Transcript of SPH Simulation of Liquid Droplet Behavior on a Water ... Simulation of Liquid Droplet Behavior on a...
SPH Simulation of Liquid Droplet Behavior
on a Water-repellent Surface Masumi Ito 2013
The wetting property of a Liquid-Solid surface is represented
by the angle which is made at the end of liquid body.
Wettability and Contact Angle
Liquid Cohesion (Surface tension) Algorithm SPH
Comparison of wettability Rebound motion (Hydrophobic case)
A liquid sphere falls and collides with solid surface (colliding velocity:0.85m/s)
The effect of surface tension is given as a attractive force between particles
Mass distribution of an SPH particle
r (:distance from the center)
Objective: To confirm Liquid-Solid contact can be properly computed using SPH method.
Surface
particle
Inside
particle
The droplet collapsed. And then……
Γ
SΓSSL ΓΓ
Liquid Air
Solid
:cos SSL Equilibrium
Condition
← Please also refer to the experimental research with the same condition,
Figure 4 in the paper “Spread and Rebound of Liquid Dropltes upon Impact on Flat Surafaces”,
Ted Mao et al., AIChE Journal, (1997) Vol. 43, No. 9, pp. 2169-2179.
0
100
200
300
0 0.5 1r/R
Densit
y (
kg/m
^3)
0 means hydrophilic
, hydrophobic 180
Back Ground The treatment of wettability is important to calculate a fluid
motion of a liquid body that touches a solid surface.
For example, the bouncing behavior of a liquid droplet is
largely changes with wettability which is seen in heat-
exchanger tubes, where it is demanded to understand and
suppress this phenomena.
This study tries to compute this bouncing phenomena using a
particle method (SPH). The effect of liquid cohesion was given
as the attraction of particles.
Investigated whether the SPH can properly calculate
the geometry of the deforming liquid surface or not.
Deforming behavior changes with wettability.
R (:Influence radius)
Conclusion: The SPH method is feasible to compute the liquid bouncing phenomena.
*Opposing vectors are canceled.
aba hCF
Ch,, : Surface tension coefficient, Particle diameter, Arbitrary constant (includes weighting function)
Results
Surface geometry agreed with experiment well for each instant.
hCF liqliq
hCSF solliq
2/)cos1( as defined ratio, Wetting: SS
Treatment of Wettability.
Hydrophobicθ=97° Droplet bounce-up and leaves wall
Hydrophilic θ=45°
No bouncing motion
Solid
particle
Particles move based on
NS equation and represent a
fluid motion
