Maximum Steam Velocities
Maximum Steam Velocities
(OP)
I have come across a statement saying that the velocity of steam should not exceed a certain % of the "Threshold Steam Speed".
Has anyone come across this term ? And if so what value is it referring to.
My normal "ruler of thumb" is that the maximum velocity of steam should not exceed 200ft/s or 60m/s. Is this assumption correct and what are the negatives associated with going over this value.
Thanks in Advance
Has anyone come across this term ? And if so what value is it referring to.
My normal "ruler of thumb" is that the maximum velocity of steam should not exceed 200ft/s or 60m/s. Is this assumption correct and what are the negatives associated with going over this value.
Thanks in Advance





RE: Maximum Steam Velocities
If the steam is wet, then I've seen potential erosion problems listed at higher velocities (superheated steam typically has a higher allowable velocity in many company specs than saturated steam). 200 ft/sec is not an uncommon velocity limit for steam in my experience.
The only other problem I see with going with higher velocities is additional pressure drop. If that isn't a problem, such as doing into a pressure let-down valve, I'd be willing to look at dropping a line size and seeing what the resulting velocity is.
RE: Maximum Steam Velocities
1- Corrosive service
2- soft metal (copper alloys or lead)
3- Presence of abrassive solids in the process fluid.
For Steam , industerial practice of Max. vel. = 350 ft/sec
However, the velocity to determine the economic pipe size depends on Line pressure which range from 50-350 ft/sec.
Regards