Crisman Annual Report 2009 - Harold Vance Department of ...

fractions involved, a detailed sensitivity analysis
of the model used for this work would be required
to assess the effects of varying the liquid content
and also the operating pressure and the phase flow
rates.
Fig. 2. CFD model of the section of interest of the ANUMET meter. The
flow is along the Z axis.
Significance
The preliminary results confirm that the twisted tape
induces a swirling motion that results in a separated
flow downstream of the device. The liquid flows
along the pipe walls, although there remains some
entrainment within the gas core. The distribution of
the phases across the pipe section is not the same
at different locations downstream of the swirler.
In particular, it appears that the efficiency of the
separation is highest at the furthermost location
from the device. However, due to the particular
geometry investigated, this study has not been able
to verify how far from the twisted tape the swirling
motion persists, and whether this is accompanied
by an efficient separation of the phases. It is in fact
believed that, due mainly to gravity effects, there is
a point where the vortex motion becomes negligible.
Future Work
For the ANUMET wet gas meter application, it is
important to understand where the maximum
liquid deposition occurs, so that the measured
film thickness would be most representative of the
total liquid hold up in the pipe. For downhole liquid
unloading applications, it is important to understand
whether the swirling motion induced by vortex
devices can actually persist up to the wellhead. More
work is needed to prove the actual flow dynamics
through these devices and the relationship between
tool configuration, flow rates, operating pressure,
well geometry (length, diameter and orientation)
and swirl persistence. Also, because of the high gas
56
Crisman Annual Report 2009