Numerical prediction of periodically developed fluid flow and heat transfer characteristics in the sinusoid wavy fin-and-tube heat exchanger

Purpose - In this paper three-dimensional numerical simulations were conducted for the periodically developed laminar flow in the sinusoid wavy fin-and-tube heat exchanger. Design/methodology/approach - A novel CLEARER algorithm is adopted to guarantee the fully coupling between the pressure and velocity, and it can not only speed. up the convergence rate, but also overcome the severe grid non-orthogonality in the wavy fin-and-tube heat exchanger. The influence of wave amplitude, fin pitch, tube diameter and wave density on fluid flow and heat transfer characteristics is analyzed under different Reynolds numbers. Findings - The numerical results show that with the increase of wave amplitude, tube diameter or wave density, both the friction factor and Nusselt number will increase, and the increase rate of friction factor is higher than that of Nusselt number. It is interesting to note that, at low Reynolds numbers the Nusselt number increases with the decrease of fin pitch, while at high Reynolds numbers, the Nusselt number increases with the increase of fin pitch. Originality/value - The numerical results presented in this paper may provide some useful guidance in the design of the wavy fin-and-tube heat exchanger with large number of rows of tubes.