要約

In this article, we report on heat transfer and pressure drop coefficients for flow boiling ofR-134a in a minichannel formed by two parallel aluminum plates. The channel walls are augmented by means of round beads. The heat transfer coefficients and pressure drops were evaluated for mass fluxes ranging from 40 to 190 kg/m²·s and inlet-exit quality bands of 0.25-0.50, 0.50-0.75, and 0.75-0.90. The minichannel evaporator design was evaluated by comparing its performance with a similar plate with a different number of round beads. These results were also compared with available correlations for a better understanding of the heat transfer mechanism in the minichannel. Over the range of parameters tested, an enhancement of two- to sixfold in the heat transfer coefficient was obtained, compared to smooth tubes with the same nominal area. From the comparison and study of correlations, a simple correlation was proposed that agrees with the experimental data within 20%.