Suction specific speed choices have consequences

摘要

A refinery engineer was in a quandary over requesrs from a project group. High volume/pressure/temperature pumps in hydrocarbon service were involved and the refinery's standards had, in 2007, been changed so as to avoid purchasing pumps that might not operate well in the lower flow region. The engineer asked if it was really practical to insist on accepting only pumps with an N_(sss) (meaning "suction specific speed") below 9,000, although decades ago his company had allowed pumps with N_(sss) values up to 12,000. But first, a greatly simplified introduction to N_(sss) and its importance.