{"id":51030,"date":"2021-01-05T05:39:36","date_gmt":"2021-01-05T05:39:36","guid":{"rendered":"\/forum\/forums\/topic\/transient-multiphase-flow-simulation-inside-a-high-length-to-diameter-ratio-pipe\/"},"modified":"2021-01-05T05:39:36","modified_gmt":"2021-01-05T05:39:36","slug":"transient-multiphase-flow-simulation-inside-a-high-length-to-diameter-ratio-pipe","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/transient-multiphase-flow-simulation-inside-a-high-length-to-diameter-ratio-pipe\/","title":{"rendered":"Transient multiphase flow simulation inside a high length to diameter ratio pipe"},"content":{"rendered":"
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Hi forum,<\/p>\n

I would like to know how can I efficiently simulate a transient multiphase flow scenario of a vertical pipe having an L\/D ratio in the order of 10^4 or so (5000 ft long with a 0.5 ft dia). I might need to simulate around 30 minutes flow. This is an example of an oil and gas well drilling scenario. I have read some papers saying the simulate may diverge due ot the high l\/d value. Some even suggested my case may take a month to simulate even on an HPC. <\/p>\n

One solution was suggested on this forum (link below) is to divide the pipe into multiple small segments and transfer profile data from segment to segment. <\/p>\n

I plan to use a 2-D geometry, probably will go with axisymmetry along the vertical axis, use VOF model, no energy equation at this point. I will have High performance Computer access. <\/p>\n

Please try to shed some light on the following points and beyond those if you can:<\/p>\n

1) How can profile transfer technique be implemented for a transient case? It will be highly transient (bunch of gas bubbles being circulated), so no chance of SS<\/p>\n

2) I can perform dimensional analysis to reduce my length but in that case, the diameter will be super small. What do you think?<\/p>\n

3) I came across the idea of creating response surface for different smaller length pipe and try to extrapolate what the conditions could be for 5000 ft pipe. But I don't have good knowledge on that front, so any thoughts?<\/p>\n

4) Any other technique you would suggest?<\/p>\n

5) I know it is difficult to tell without knowing the configuration of HPC, but just to get a ball park as I have no knowledge using HPC, if I actually do the simulation full-scale with 2-D axisymmetry for 30 minute of flow, how long the simulation may take?<\/p>\n

<\/p>\n

<\/p>\n<\/p>\n

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