Liquid film thickness of vertical upward annular flow in narrow rectangular channel

The interfacial shear stress and liquid film thickness are very important to establish the basic model of annular flow in practical applications. In this paper, the liquid film thickness of annular flow in a narrow vertical rectangular channel with a cross-sectional area of 70 mm x 2 mm was measured based on the PCB liquid film sensor. According to the experimental results, the average liquid film thickness, base film thickness and interfacial friction factor were calculated and analyzed. The experimental results showed that the liquid film thickness was affected by the gas phase velocity and the liquid phase velocity, but the effect of the gas phase velocity on the liquid film thickness decreased gradually with increasing gas phase velocity. Moreover, the interfacial friction factor was obvious affected by the liquid phase velocity at low gas phase velocity, but this influence gradually decreased with increasing gas phase velocity. Existing correlations for above parameters were summarized and evaluated with the current data, and there was a large deviation between the predicted results and the experimental results. Therefore, a new correlation for above parameters was proposed, respectively. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The experimental results showed that the liquid film thickness was affected by both gas phase velocity and liquid phase velocity, with the effect of gas phase velocity gradually decreasing as its speed increases in annular flow. The interfacial friction factor was significantly influenced by liquid phase velocity at low gas phase velocity but this impact decreased with increasing gas phase velocity. Existing correlations for the parameters showed a large deviation between predicted and experimental results, leading to the proposal of new correlations for the parameters.