A Numerical Study of the Influence of Surface Roughness on the Convective Heat Transfer in a Gas Flow
F. Dierich; and P.A. Nikrityuk

Source CMES: Computer Modeling in Engineering & Sciences, Vol. 64, No. 3, pp. 251-266, 2010
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Keywords Convective heat transfer, Roughness, Immersed boundary method
Abstract This work presents a numerical investigation of the influence of the roughness of a cylindrical particle on the drag coefficient and the Nusselt number at low Reynolds numbers up to 40. The heated cylindrical particle is placed horizontally in a uniform flow. Immersed boundary method (IBM) with a continuous forcing on a fixed Cartesian grid is used. The governing equations are the Navier Stokes equation and the conservation of energy. A finite-volume based discretization and the SIMPLE algorithm with collocated-variables and Rie-Chow stabilization were used to solve the set of equations. Numerical simulations showed that the impact of the roughness on the drag coefficient is low. But we found out that the roughness has significant impact on the surface averaged Nusselt number. In particular, the Nusselt number decreases rapidly with increase of the roughness thickness. Based on the numerous simulations a mathematical dependency of the heat transfer efficiency factor on the surface ratio was obtained.
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