3. Results and discussions
3.1. Model validation
Before any changes to the original valve configurations, the
model developed for the original valve was validated by actual
measurements and observations. The fluid velocity at the inlet
and outlet of the product fill valve are shown in Fig. 3. The inlet
plane velocity distribution shows a uniform velocity distribution
that is in good agreement with the core-annular nature
of the pipe flow. However, the velocity contours at the outlet
shows a non-symmetrical nature with the velocity shifted
from the centre. This unexpected distribution is due to the
internal shape of the valve as described in details by the
research work carried out by Rahaman et al. (2008). One of the
objectives of changing the valve configurations is to improve
this velocity contour at the outlet. Fig. 4 shows the velocity
contours at the mid-plane through the valve assembly at the
fully open valve position. The flow is found to be fully developed
with the mass flow rate of approximately 5.07 kg/s, which
is very close to the manufacture’s rated product filling rate
of 5.0 kg/s. This provides a basic validation of the model. The
model also predicted a local pressure drop in areas where the
flow turns 60◦ severe enough to cause cavitation [Area 1]. This