Convective heat transfer augmentation through vortex shedding in sinusoidal constricted tube
Résumé
Purpose - The purpose of this paper is to analyse the convective heat transfer of an unsteady pulsed, laminar, incompressible flow in axisymmetric tubes with periodic sections. The flow is supposed to be developing dynamically and thermally from the duct inlet. The wall is heated at constant and uniform temperature. Design/methodology/approach - The problem is written with classical homogeneous boundary conditions. We use a shift operator to impose non-homogeneous boundary conditions. Consequently, this method introduces source terms in the Galerkin formulation. The momentum equations and the energy equation which govern this problem are numerically solved in space by a spectral Galerkin method especially oriented to this situation. A Crank-Nicolson scheme permits the resolution in time. Findings - From the temperature field, the heat transfer phenomenon is presented, discussed and compared to those obtained in straight cylindrical pipes. This study showed the existence of zones of dead fluid that locally have a negative influence on heat transfer. Substantial modifications of the thermal convective heat transfer are highlighted at the entry and the minimum duct sections. Practical implications - Pulsated flows in axisymmetric geometries can be applied to medical industries, mechanical engineering and technological processes. Originality/value - One of the original features of this study is the choice of Chebyshev polynomials basis in both axial and radial directions for spectral methods, combined with the use of a shift operator to satisfy non-homogeneous boundary conditions. © Emerald Group Publishing Limited.