Numerical analysis of quasi-steady flow characteristics in large diameter pipes with low liquid loading under high pressure

• Wavy thin film flow and droplet transport in a wet gas pipeline were studied.
• Droplets and liquid film were considered together. The distribution of the film and droplet fraction changed periodically.
• Secondary flow enhanced the transport of droplets to the upper side of the pipe and supplemented the upper film.

Computational fluid dynamics (CFD) modeling was carried out to study wavy thin film flow and droplet transport in high-pressure natural gas pipelines with low liquid loading. The interactions between droplets and thin film were considered. The results of the CFD analysis showed periodic fluctuation in the axial film distribution in the straight pipe. In the bend, gas streamlines originated from the inside of the bend. As the gas velocity was increased, more droplets were stripped, while the stripped droplets were deposited further away. Liquid film peak formation and droplet motion were attributed to the actions of centrifugal force and gravity in the bend. Secondary flow enhanced the transport of droplets to the upper side of the pipe and supplemented the upper film. The droplet fraction distribution changed periodically with time. The accumulation of droplets on the film has a periodic characteristic. Dense droplets tended to accumulate in regions of low vortices. The results of the CFD simulation were in good agreement with previous experimental data and theoretical analyses reported in the literature.

The quasi-steady state flow characteristics in large-diameter pipes with low liquid loading under high pressure were studied by CFD. The droplets and liquid film were considered simultaneously in the model. The liquid film peak formation and droplet motion were attributed to the actions of centrifugal force and gravity in the bends in the pipe. Secondary flow enhanced the transport of droplets to the upper side of the pipe and supplemented the upper film. There was a periodic fluctuation in the axial film distribution. The droplet fraction distribution changed periodically over time. The accumulation of droplets on the film had a periodic characteristic.Figure optionsDownload high-quality image (354 K)Download as PowerPoint slide