Proceedings of the 5th World Congress on Mechanical, Chemical, and Material Engineering (MCM19), Lisbon, Portekiz, 15 Ağustos 2019 - 17 Mart 2020, ss.1-10
The research presented in this paper is a part of long research programme on flow boiling in rectangular metallic
microchannels. The present experiments were conducted in three rectangular oxygen-free copper microchannels with the same hydraulic
diameter (Dh = 0.56 mm) and length (L = 62 mm) but different aspect ratios (β = width/height = 0.5, 2.56 and 4.94). The range of mass
flux and heat flux was between 200-800 kg/m2
s and 4-1350 kW/m2
respectively with an inlet subcooling of ~14 K. The results consistently
indicated that the flow boiling pressure drop increased monotonically with heat and mass flux. Also, the flow boiling pressure drop
increased with increasing vapour quality. The flow boiling pressure drop was found to increase with the decreasing channel aspect ratio.
The experimental flow boiling pressure drop data were compared with widely used macro and micro scale correlations. The macro-scale
correlations could not predict the experimental data well, while some of micro-scale correlations predicted the experimental results
reasonably well.