Investigation of Flow Boiling in Micro-Channels: Heat Transfer, Pressure Drop and Evaluation of Existing Correlations

In this study, the flow boiling heat transfer and pressure drop characteristics of refrigerant R134a in micro-channels were experimentally investigated. The tests performed circular horizontal with inner diameters 0.5 mm 1 a heating length 300 mm. mass velocities varied from 500 kg/m2s to 2500 kg/m2s, fluxes 15 kW/m2 147 kW/m2. coefficient (HTC) frictional (FPD) measured discussed detail. According results, HTC was significantly affected by flux, whereas it independent velocity. Nucleate dominant mechanism for micro-channels. comparison channel, channel shows better performance transfer, maximum increase approximately 22 %. addition, FPD increased increasing velocity decreasing diameter. Finally, several existing correlations evaluated comparing them experimental values. Tran’s correlation (1996) presented agreement terms average HTC, while FPD, model Kim Mudawar (2013b) showed good prediction accuracy.