Accurate Prediction of Friction Factor for Laminar Flow in Irregular Annuli

Steady fully-developed laminar flows of an incompressible fluid in an annulus of different irregular cross-sectional geometry are investigated numerically. Accurate prediction of the friction factor of these flows is obtained using the high-order finite element method. This study is focused on the annular flow between rectangular and triangular ducts under all possible arrangements. Our results showed excellent agreement with the corresponding results available in the literature. It is found that for all cases considered, the increase in the hydraulic radius of the annular area would lead to a decrease in the value of (fRe). In addition, for a fixed hydraulic radius: it is found that the square in triangle case (TS-case) has the lowest value of (fRe) whereas the square in square case (SS-case) has the largest value of (fRe).