On the effect of liquid viscosity on interfacial structures within churn flow: Experimental study using wire mesh sensor

A Wire Mesh Sensor (WMS) with a 16×16 spatial resolution was employed to discover the effects of liquid viscosity on the behavior of churn flow in a vertical 76.2 mm pipe. Three liquid viscosities of 1, 10, and 40 cP, and superficial liquid velocities of 0.46, 0.61, and 0.76 m/s were employed; whereas, superficial gas velocity ranged from 10 to 27 m/s. Different techniques such as Probability Density Function (PDF), and 2-D and 3-D image reconstruction methods were applied to study the flow. It was noticed that increasing liquid viscosity not only affected the flow pattern but also the appearance frequencies of interfacial structures.