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

Properties and Conditions (Case 1) Phase 1 – water ρw = 1000 kg/m3 μw = 0.0008 kg/m-s Phase 2 – air ρa = 1.225 kg/m3 μa = 1.7894e-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

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 = 1.0+2.63/500 = 1.00526. Tai defines the nondimensional pressure as . Therefore the gas a liquid pressures are set as:

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

Comparison with Tai 5 6 7

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

Pressure Contour at inlet Strange localized pressure drop Pa

Pressure at Inlet Pressure should look like this:

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

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

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

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