A Numerical Approach to Study Shell-Side Fluid Flow in Shell-and-Tube Heat Exchangers

The detailed CFD simulation of the shell-side flow inside shell-and-tube heat exchangers results prohibitive for large-size components, due to the large number of tubes, together with the multi-scale nature of the flow features. To overcome this issue, the porous media approach can be adopted, substituting the tube bundle with a porous domain, where a suitable momentum sink term in the Navier-Stokes equation is provided. In this paper, a novel numerical approach to estimate the crossflow shell-side pressure drop is presented: a complete characterization of the tube bundle was performed by running 2D-CFD steady-state isothermal analyses, collecting pressure gradient magnitudes and directions for different mass flow rates and angles of attack of the incoming flow. The approach was validated against numerical results and compared to the methodologies currently available. Models, assumptions, and boundary conditions are herewith reported and thoroughly discussed, alongside the main results obtained.