CH-03-13-4 -- Pressure Drop and Visualization of R-134a Two-Phase Flow in a Rectangular Microchannel PDF

Adiabatic two-phase flow of R-134a has been characterized in a rectangular channel with a hydraulic diameter 0.168 mm and the aspect ratio 0.1. Two-phase flow pressure drop and flow visualization were performed in the range of mass flux from 279 to 461 kg m^-2 s^-1 and vapor quality from 0.05 to 0.95. The measured pressure drops were compared with twelve existing correlations. The results showed that most of the correlations overpredict the experimental data. The flow visualization demonstrated that the flow patterns in the microchannel are similar to those in minichannels. The slug/plug flow and annular flow are the predominant flow regimes, and the bubble flow only occurs when quality is very low.

Units: SI