Experimental investigation on flow boiling pressure drop of R600a in multiport minichannel tube.

An experimental study on boiling of refrigerant R600a in a multiport flat aluminium tube with 7 parallel mini channels with rectangular section and hydraulic diameter of 1.47 mm is presented. The effect of heat flux and mass velocity on frictional pressure drop was investigated for a constant saturation temperature and pressure. The ranges of these parameters are 50 to 200 kg/m²s and 5 to 27 kW/m², respectively for the mass velocity and heat flux, and the saturation temperature of 20°C. It was possible to observe the significant influence of mass velocity in pressure drop. The effect of acceleration component is also analysed. The refrigerant flow pattern is a very important parameter which influences the pressure drop. The images of flow patterns for different conditions were registered and the flow patterns observed were mainly slug, intermittent and annular. Isolate bubble and plug patterns were observed in specific conditions, as high mass velocity and low heat flux, for low vapor quality.