Two-Phase Pressure Drop of Ammonia in a Mini/Micro-Channel

Experiments have been performed to investigate two-phase pressure drop in a circular vertical mini-channel made of stainless steel (AISI 316) with internal diameter of 1.70 mm and a uniformly heated length of 245 mm using ammonia as working fluid. The experiments are conducted for heat flux range of 15 to 350 kW/m² and mass flux range of 100 to 500 kg/m²s. A uniform heat flux is applied to the test section by DC power supply. Two phase frictional pressure drop variation with mass flux, vapour quality and heat flux was determined. The experimental results are compared to predictive methods available in literature for frictional pressure drop. The Homogeneous model and the correlation of Mu¨ller Steinhagen et al. [14] are in good agreement with our experimental data with MAD of 27% and 26% respectively.