An Experimental Study on Transient Pressure Changes in a Horizontal Two-Phase Slug Flow

Transient flow in a conduit is an unsteady flow, followed by the change in the flow rate. Transient flow analysis is commonly based on the assumption of no air entrainment in the liquid phase. However, air entrainment in the liquid flow frequently occurs in the pipelines. Experimental study has been carried out to investigate the characteristics of transient pressure in a two-phase, air-water slug flow inside a rectangular, horizontal pipeline. Pressure surges propagating the pipeline that results transient pressure changes have been studied by rapidly closing a sluice gate inside the pipeline. The pressure variations have been recorded by installing different pressure transducers to the pipe. The results showed that increasing the air/water discharge ratio affects the transient pressure distribution in pipeline significantly. In the downstream 10% of pipeline length, pressure variation is considerably sharp, fast damping, and with higher peak. In other sections of conduit, low-frequency pressure changes were observed which were damped slowly.