Effect of channel geometry on boiling heat transfer and pressure drop of R32 inside horizontal multiport tubes.

This study was conducted to investigate the flow boiling heat transfer and pressure drop characteristics of R32 in horizontal multiport tubes with circular and triangular mini-channels. The heat transfer and pressure drop characteristics of the boiling flow were measured over a range of mass velocities from 50 to 400 kg/(m2s), a range of heat fluxes from 5 to 20 kW/m2, and at a saturation temperature of 15°C. The pressure drop characteristics were also measured for adiabatic two-phase flow. The effects of the channel geometry on the pressure drop and boiling heat transfer characteristics were clarified. The measured frictional pressure drop was compared to that predicted by existing correlations.