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

Abstract

In the churn flow regime, periodical interfacial structures such as liquid slugs and huge waves can coexist and undoubtedly, a phase property such as liquid viscosity can dominate the behavior of these structures. Regrettably, neither are the characteristics of churn flow widely understood nor have the effects of liquid viscosity on gas–liquid flow received enough attention.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 76.2mm pipe. Three liquid viscosities of 1, 10, and 40cP, and superficial liquid velocities of 0.46, 0.61, and 0.76m/s were employed; whereas, superficial gas velocity ranged from 10 to 27m/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.