Dryout characteristics during flow boiling of R134a in vertical circular minichannels

Abstract: In this paper, the experimental results of dryout during flow boiling in minichannels are reported and analysed. Experiments were carried out in vertical circular minichannels with internal diameters of 1.22mm and 1.70mm and a fixed heated length of 220mm. R134a was used as working fluid. Mass flux was varied from 50kg/m2 s to 600kg/m2 s and experiments were performed at two different system pressures corresponding to saturation temperatures of 27°C and 32°C. Experimental results show that the dryout heat flux increases with mass flux and decreases with tube diameter while system pressure has no clear effect for the range of experimental conditions covered. Finally, the prediction capabilities of the well known critical heat flux (CHF) correlations are also tested. [Copyright &y& Elsevier]