LAUSR

The gas–liquid contact area can be increased by the gas–liquid swirl flow, and the heat and mass transfer efficiency between gas and liquid can be enhanced by the gas–liquid swirl flow. The gas hydrate formation can be promoted by the swirl flow. The swirl flow can ensure the safety of the natural gas hydrate slurry. The flow pattern and conversion law of gas–liquid swirl with a twist tape should be investigated, and numerical simulation has been carried out by using the Reynolds stress model and the level set model. As a result, four different flow patterns are obtained, namely, swirl-stratified flow, swirl bubble flow, swirl slug flow, and swirl annular flow. The influence of gas–liquid-phase velocity on the flow pattern is investigated. The drag force generated by the two-phase slip velocity can change the gas form. At the same time, the flow pattern at different positions of the pipe will also change because of the attenuation of the swirl flow. Finally, the flow pattern map of the gas–liquid swirl flow is accomplished, and it is compared with the Mandhane flow pattern map. The flow boundary of the swirl bubble flow and the swirl annular flow is predicted.