gas hold up in bubble

Shelly

hi all i need some help regarding bubble column

My gas hold up profile is not getting :::lz help

I m following the paper of R.krishna(2001)

Geometry: D-0.14m, initial liquid height: 0.9m Superficial gas velocity: 0.019m/s to 0.169 m/s

U Transitional â€"0.034m/s

Phases â€"small bubble â€"4 mm

Large bubble â€"32mm Water

Below U Transitional only small bubble phase consider

Boundry condition :

Inlet---velocity inlet

Outlet----velocity inlet 2

I startes with course grid : tolal 9000 grids (slightly dence at diffuser and wall)

Different Diffuser for small n large bubble (.00175mm edge ) small bubble diffuser is near to wall Large bubble diffuser is near to center

I calculate inlet velocity ar diffueser =superficial velocity/volume fraction

Outlet velocity is calculate by mass balance as

V(inlet) * fraction*edge(i.e.velocity inlet area) *density = v(oulet) * fraction*edge(i.e.velocity inlet area) *density

Currently I m simulating only for homogenious flow

For this I m using : FLUENT Version: 2d, segregated, eulerian, ske, unsteady (2d, segregated, Eulerian, standard k-epsilon, unsteady) Release: 6.2.16 Quack ,1 st order coupling