TY - JOUR
TI - Hagen number versus Bejan number
AU - Awad Mohamed M
JN - Thermal Science
PY - 2013
VL - 17
IS - 4
SP - 1245
EP - 1250
PT - Article
AB - This study presents Hagen number vs. Bejan number. Although their physical  meaning is not the same because the former represents the dimensionless  pressure gradient while the latter represents the dimensionless pressure  drop, it will be shown that Hagen number coincides with Bejan number in cases  where the characteristic length (l) is equal to the flow length (L). Also, a  new expression of Bejan number in the Hagen-Poiseuille flow will be  introduced. At the end, extending the Hagen number to a general form will be  presented. For the case of Reynolds analogy (Pr = Sc = 1), all these three  definitions of Hagen number will be the same.