Numerical Investigation of Heat Transfer Enhancement in Wavy-Walled Tubes Filled With Porous Media

This study investigates heat transfer and pressure drop in wavy-walled tubes filled with porous media under local thermal equilibrium (LTE) conditions. A two-equation k-omega SST turbulence model is implemented for the simulations. A Darcy-Brinkman-Forchheimer (DBF) model simulates the flow within porous domains. Based on Nusselt number, friction factor, and performance evaluation criteria (PEC), effective parameters such as wave amplitude, Darcy number, and particle diameter of porous media are investigated. As a result of the porous material addition to the wake region of wavy-walled tubes, the center of recirculation vortexes is shifted upstream, and the vortex intensity is reduced. Vortexes disappear in some cases. In these regions, the local Nusselt number increases due to the convergence of this phenomenon due to the placement of porous material in the divergent section of the wavy-walled tube. The results show that heat transfer and pressure drop variations are related to the Darcy number and the design point should be outside this region. Also, it was found that the Darcy number reduction increased the interaction between porous material and flow and PEC number decreases as shear stress increases in the convergent section. As a result of reducing the size of porous media particles, there is increased collision between fluid and particles, resulting in streamlines conforming to the tube wall and no reverse low. The results reveal that in this article, the maximum PEC number increases to 1.364, which indicates that affordable energy supply and improvement in energy efficiency are available with new ideas.