Experiments on accumulation and sweep-out of liquid in a low elbow of a gas/liquid pipeline

The aim of this project is to obtain fundamental insight in the fluid mechanics of liquid accumulation and transport in gas and oil pipelines. If the gas velocity is low, liquid will remain in the pipeline, until it is swept out from the pipeline as a liquid slug. This frequently occurs in pipeline applications in the gas and oil industry, where liquids (i.e. oil/condensate and water) or transported together with hydrocarbon gas. Liquid accumulation can be undesired as this can cause pipeline corrosion (in the presence of water pools), or can give unstable flow behaviour where the liquid slugs may flood the downstream separator. Sometimes liquid accumulation may also be desired, for example during an emergency blowdown, where the gas is produced through a flare system and the liquid should preferably remain in the pipeline.

In this project a representative flow experiment will be set-up. This should be for twophase flow (air/water) and for threephase flow (air/water/oil). The low elbow is pre-filled with liquid, and thereafter the gas velocity is gradually increased to visualize when and how liquid starts to be swept with the gas out of the elbow. Those experiments can be carried out for various initial liquid holdup values, for various liquid densities, and for various viscosities. Measurement techniques will include: flow visualization, pressure transducers, and the conductivity wire mesh. Results will be compared with other experimental data available in the literature as well as with model predictions.

Figure: Liquid accumulation in low elbow of gas/liquid pipeline.

Supervisors: Prof. dr. ir. R.A.W.M. Henkes and dr. ir. M.J. Tummers