A computational study of curvature effect on pressure drop of gas-liquid two-phase flow through 90 degree elbow

Abstract

The CFD analysis of air-water two-phase flows was performed in a 90o vertical to horizontal elbows made of PVC with four different inside diameters (25 mm, 50 mm, 75 mm, and 100 mm) with six different curvature radius to diameter ratios (R/D) 1, 2, 4, 6, 8, and 10. Pressure drops were investigated at various upstream and downstream locations using computational, experimental, empirical methods. The most effective method in investigating and determining total pressure drop of two-phase flow in pipes and bends is considered to be computational study. The CFD simulations were performed using ANSYSY 19.2 FLUENT and a mixture model. The studies were conducted under the following two-phase conditions: mass quality from 1-50% and mass flux from 350-1000 kg/m2s. The results show that the impact of these significant parameters are important and dramatic specially at high curvature radius, mass flux and mass quality. The results of the CFD study demonstrated a substantial loss in energy and pressure as the fluid exits the elbow section, and also a higher drop in pressure observed at higher air velocity. Also, higher pressure drops were obtained with increasing pipe diameter in one side, and with decreasing R/D on the other side. Finally, the current results were verified with the empirical and experimental studies and a good agreement were obtained.