Effect of Boundary Conditions and Turbulence Treatment on the Simulated Performance of a Ribbed Heat Exchanger

Ribbed surfaces are widely employed in heat exchangers to enhance the convective heat transfer and hence the overall thermal efficiency. This study aims to investigate the effect of two important assumptions made in computational fluid dynamics simulations, i.e. the thermal boundary conditions and the turbulence modeling, using a popular test case for the heat transfer over a continuous ribbed plate was taken as a reference. Numerical simulations were performed both neglecting and considering the conduction within the solid, to verify the effect of different thermal boundary conditions on the fluid domain, and with several turbulence treatments, ranging from common Reynolds-averaged Navier-Stokes approaches to higher fidelity but more computationally intensive Large Eddy Simulations. The results demonstrate that both aspects are important for an accurate prediction of the thermal performance of ribbed channels.