Learning Forum

[taka8170]

Dear all,

I am trying to use CFX to do an analysis on how mist spreads when water is sprayed through a single nozzle into the air as shown in the figure, but the results seem to be wrong. Please advise.
The model is a nozzle with a simple orifice geometry as shown in the figure.
The main settings of CFX are as follows

Domain
Air: Continuous fluid
Water: Dispersed Fluid (300 micron)
Free surface model: Standard
Fluids Pair Models: Surface Tension Coefficient

B.C.
Inlet: Total pressure (Volume Fraction, Air:0, Water:1)
outelt:Opening (Volume Fraction, Air:1, Water:0)

Since only water flows in at the inlet, water must be 100% in the nozzle, but the water volume fraction in the nozzle cross-section is not equal to 1. At the inlet boundary, the water volume fraction was completely 1.
Note that we have not included a cavitation model, but the maximum flow velocity is about 10 m/s, so we do not expect cavitation to occur.
Also, looking at the Air Velocity, the situation has a velocity distribution even inside the nozzle.
Is the setting wrong to begin with?

Thank you,

[DrAmine]

Why is water defined as diserpsed Fluid? I assume you require a free surface model so the whole momentum should be homogeneous (So compressive with one velocity field). It will be helpful to patch the near inlet regions with 100% liquid.