| Summary: | Slug flow in a multi-phase flow pattern of piping systems should be
avoided because it can lead to blasting pipe, structural failure due to vibration, or
lead to corrosion caused by cavitation. Plug flow is a part of the slug flow. Plug
flow is transition of flow pattern from stratified to slug flow. It has simillar
characteristics with slug flow and it has also potensial danger in nuclear reactor
on loss of coolant accident (LOCA) case. Plug flow can be seen with visualization
and signal analysis method.
In this study, characteristic of plug flow and effects due to changes pipe
diameter was investigated. The plug flow mechanism was studied by change the
superficial velocity of gas (JG) from 0,12 to 0,70 m/s on change of liquid
superficial velocity (JL) from 0,25 m/s to 1,13 m/s for each pipe diameter of 16
and 26 mm. The CECM (constant electric current method) method is compared
with the visualitation method.
The result of CECM is used to analysis liquid hold up, cross correlation,
Probability Distribution Function (PDF), and Power Spectra Density (PSD).
From the analysis is known that the higher of gas velocity superficial, the higher
of velocity of gas plug for each pipe diameter. Liquid hold up is indicating
transient characteristic of plug flow. The result of visualitation methode is used to
analysis shape and size plug, wave frequency and wave velocity. From the
analysis is known that the shape and size of the plug in the pipe diameter 16 mm
is smaller compare with pipe diameter 26 mm. The pipe diameter 16 mm produces
more plug than pipe diameter 26 mm, it caused higher wave frequency than pipe
diameter 26 mm.
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