TY - JOUR
TI - Extending the Bejan number to a general form
AU - Awad Mohamed M
AU - Lage J L
JN - Thermal Science
PY - 2013
VL - 17
IS - 2
SP - 631
EP - 633
PT - Article
AB - A modified form of the Bejan number (Be), originally proposed by  Bhattacharjee and Grosshandler for momentum processes, is obtained by  replacing the dynamic viscosity (m) appearing in the original proposition  with the equivalent product of the fluid density (r) and the momentum  diffusivity of the fluid (n). This modified form is not only more akin to the  physics it represents but it also has the advantage of being dependent on  only one viscosity coefficient. Moreover, this simple modification allows for  a much simpler extension of Be to other diffusion processes, such as a heat  or a species transfer process, by simply replacing the diffusivity  coefficient. Consequently, a general Be representation for any process  involving pressure-drop and diffusion becomes possible. It is shown that this  general representation yields analogous results for any process satisfying  the Reynolds analogy (i.e., when Pr = Sc = 1), in which case the momentum,  energy and species concentration representations of Be turn out to be the  same.