Predictive models for flow boiling in minichannels

More and more attention is being paid to the study of two-phase flow and boiling heat transfer in minichannels in the recent years. Boiling in minichannels is common application in compact heat exchangers, which are largely used in the emerging technologies, such as cooling of electronic components. This process presents also strong potential for improving refrigeration and airconditioning systems, since it allows to reduce inventory charge and air-side pressure drop. Minichannels are also to be recommended with high pressure refrigerants, such as carbon dioxide. The present paper aims to assess available correlations for boiling in minichannels by comparing heat transfer data taken by seven independent laboratories to the predicting models by Thome et al. (2004), Kandlikar e Balasubramanian (2004), Tran et al. (1996), Warrier et at. (2002). Experimental data included in the database covers a wide selection of fluids (CO2, R11, R12, R22, R134a, R123), a wide range of mass velocities (50-600 kg m-2 s-1), heat fluxes (5-200 kW m-2), diameters (0.8 -3 mm) and geometries (circular cross section, rectangular cross section, single channel, multiport channels).