Abstract:
Flow boiling performance is affected by several factors, such as channel
characteristics and working fluid types. It is found that there is still limited study that discusses
the use of binary mixtures combined with high aspect ratio microchannels. The aim of this study
is to investigate the flow fluctuation during flow boiling of binary mixtures in rectangular
microchannels. Here, a 6 mm width and 0.3 mm depth rectangular channel was utilised, and it
represents a hydraulic diameter of 571 μm and an aspect ratio of 20. In the present works, a mass
flux of 10 kg m−2 s−1 was used, and the heat flux ranged from 15.2 and 21.0 kW m−2. The image
processing technique was applied to track the bubble tail movement. In addition, the thermal
camera was utilised to gather the wall temperature distribution of the channel. The preliminary
results show that the use of binary mixtures influences the vapour fraction in the channel and the
flow fluctuation characteristics. Some differences are observed in terms of wall temperature
characteristics. However, the rapid increase of wall temperature is found in the outlet region for
high flux cases under all liquid types which suggests the dominance of dry out event.
