| Summary: | rate The Fluid flow in a system need to be identified because it influences
the performance of the system. Measuring tool is needed for flow monitoring. A
number of systems in industy requires measurement system using non-invasive
method, with low cost and flexibility of installation. The ultrasonic flow meter is
used to monitor the flow without any changes in the cross sections. Ultrasonic
flow meter is used to measure two phases flow rate due to gas or liquid particles
flow. The ultrasonic flow meter is easy to install, movable, and do not cause the
friction loss. In this study, water and air has been used as working fluids. A plate
is placed in the entrance region in order to prevent water mixed with air so that
stratified flow is easy to obtain. Pipe used in this investigation is the acrylic pipe
with 18 mm diameter and 5 mm thickness which is transparent in the benefit of
observing the flow behaviour, a pair of transducer consists of transmitter and
receiver with a frequency of 40 kHz. Function generator is used to generate
ultrasonic waves frequency connecting to the transmitter as a transmitter signal.
Signal transmitted then has been received by a receiver connecting with a digitali
oscilloscope. This study aims to know the effect of temperature changes on void
fraction (α) based on visualization data, amplitude value resulting from ultrasonic
spectrum frequency and transit time of ultrasonic waves through its medium.
Superficial velocity of water (JL) used is 0,03 m/s - 0,07 1 m/s, superficial velocity
of air (JG) is starting from 2,2 m/s until 3,81 m/s, with the inlet temperature 30
o
C,
50
o
C, and 70
o
C, respectively.
been It have found that in the same superficial velocity of water (JL), the
increasing of the average superficial velocity of air (JG) cause the void fraction
(Χ) are increasing but in the same superficial velocity of air (JG), the increasing of
the average superficial velocity of water (JL) cause the void fraction (Χ) are
decreasing. In the same superficial velocity of air (JG), the increasing of
temperature causes the increasing of the average void fraction (Χ). The increasing
of water flow rate (QL) and temperature cause the average amplitude decreased
and the increasing of air flow rate (QG) causes the steady average amplitude. With
the increasing of temperature showed that the transit time becomes reduced.
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