This plot shows the computed mass flux in slug/sec vs iteration count. there are four curves, corresponding to the mass flux at the entrances to zones 1, 2, and 3, and the exit of zone 3.

The mass fluxes at the entrances to zones 1 and 2 are identical, and vary only slightly from their initial value at iteration 0, reaching an essentially constant value of about 0.005 after about 700 iterations.

The mass flux values at the entrance and exit of zone 3 vary more widely in the initial few hundred iterations, and both reach an essentially constant value of about 0.010 after about 800 iterations.