Experimental Assessment of Local Head Losses in Needle and Globe Valves Under Horizontal Multiphase Flow

This study presents an experimental investigation of the hydrodynamic behavior of multiphase flows (water–air and oil–air) through needle and globe valves. The experiments were conducted at the Center for Petroleum Studies (CEPETRO) of the University of Campinas (UNICAMP), using an acrylic test section with an internal diameter of 19 mm installed in a horizontal configuration. The objective was to characterize the localized head loss, represented by the localized head-loss coefficient (K), under different multiphase flow patterns: annular and elongated bubbles. The transparent valves enabled direct visualization of flow structures, such as recirculation zones, as well as the formation of flow patterns upstream and downstream. The results showed that the needle valve consistently exhibited higher head-loss coefficients than the globe valve, particularly at low opening ratios and low Reynolds numbers. For both the annular and elongated-bubble patterns in water–air flow, the globe valve displayed (K) values significantly lower (typically between 1.8 and 7) than those of the needle valve (ranging from 4.95 to 27.0), highlighting the effect of a smoother internal geometry. The use of oil–air flow increased localized losses compared to water–air, reflecting stronger viscous effects and lower mixture Reynolds numbers. Additionally, flow visualization confirmed low-pressure regions and strong recirculation zones inside the valves in the restriction region (the plug area of the needle and globe valves).