1. Isothermal Two-Phase Pipe Flow Sim
Update: Determined the correct properties and conditions from the nondimensional values used by Tai’s paper

2. Properties and Conditions (Case 1)
Phase 1 – water ρw = 1000 kg/m3 μw = kg/m-s
Phase 2 – air ρa = kg/m3 μa = e-05 kg/m-s
Case 1 - Rew = 2000, We = 500. Therefore set the inlet velocity, U, and the surface tension coefficient, σ, from these values
note, we can’t use the actual surface tension coefficient of water because the We number wouldn’t match the one in the paper

3. Properties and Conditions (Case 1)
The total simulation time and the time step needs to match the paper’s nondimensional total simulation time . Tai defines the nondimensional time as Therefore set the tend and Δt to:
The nondimensional pressure is set as 1 outside of the liquid. The liquid nondimensional pressure is pl= pg+k/We = /500 = Tai defines the nondimensional pressure as Therefore the gas a liquid pressures are set as:

4. Results at t*=6 (t=0.375s)
Phase Contour 2 4 6 8
10 cm

5. Comparison with Tai 5 6 7

6. Pressure Contour
Pressure build-up in entrance region above inlet pressure.
Tai Pa

7. Pressure Contour at inlet
Strange localized pressure drop Pa

8. Pressure at Inlet
Pressure should look like this:

9. Axial Variation of Pressure
Pressure is too high at inlet
Pressure drop is smaller when compared to Tai paper
ΔP over x = 0 to 10 is
~0.03 for Fluent
~0.09 for Tai

10. Velocity Vectors
Inlet
Gas boundary layer builds up quickly
m/s

11. Velocity Vectors Bubble Leading Edge
Greater velocity gradient where bubble expands
Gas velocity speeds in front of bubble leading edge
m/s

12. Status
Need to work on establishing the correct pressure at the inlet.