Numerical investigation of fully developed laminar flow in irregular annuli: Square-circular ducts
Numerical study is carried out on fully developed laminar axial flow of incompressible Newtonian fluid in irregular annuli of different cross-sectional geometry. Accurate prediction of the friction factor of this flow was obtained using high-order finite element method. Investigations are performed for the annular flow between rectangular and circular ducts under all possible arrangements. The governing equations are solved by an efficient finite element technique. It was found that a higher annular area-ratio will lead to a monotonic increase in (f Re) value in the case of regular annuli, and will lead to an increase followed by a decrease in (f Re) value in the case of irregular annuli. Furthermore, this study illustrates that irregular annuli have lower (f Re) value than regular annuli, and that the square-in-circle case (SC-case) has the lowest (f Re) value whereas the circle-in-circle case (CC-case) has the highest (1 Re) value. The finite element technique developed in this study was validated against the already reported numerical results in the literature, and the results presented in this work show excellent agreement. Copyright (C) 2009 John Wiley & Sons, Ltd.
laminar flow friction factor fully developed flow irregular annulus numerical analysis