Slug Number PI-SS

[ikonovakovic]

Can anyone provide me a equation for Slug Number PI-SS, being calculated by simulation softwares, as Pipesim.
Thank you

[mohamedellejmi]

The likelihood of severe riser slugging is determined by the PI-SS correlation. Slugging will occur if there is a segregated flow regime and a PI-SS number less than one. The size of the slug is determined by using the following formula. Slug Size = Riser Volume/PI-SS number.

But for hydrodynamic Slugging, this is determined by use of the SSB or Norris Correlations. You need a slugging flow regime for this to occur such as intermittent. The slug size and frequency is taken from the slug length and frequency table in the output file. It is normal practice that the slug catcher is sized for the 1 in 1000 slug. These correlations can predict huge slug sizes with volumes greater than the holdup in the pipeline. Therefore one must be careful to check the holdup as the slug cannot be bigger than the total amount of liquid in the pipeline.

PIPESIM cannot accurately predict terrain slugging. However the holdup increases as the pipeline goes over successive humps may indicate a propensity for terrain slugging.

Hope this helps...