Impact of wave inclination on enhancement heat transfer for a wavy- fin compact heat exchanger with circular and elliptical tubes for staggered tube arrangement

Resumo

With the increasing industrial development, the improvement of several processes and devices
represents a great need, especially for thermal devices. The present work evaluates the enhancement of heat
transfer in a compact heat exchanger with wavy-fins, operating at Reynolds number of 180 to 900, through
modified inclination of wavy-fin in relation to the main flow direction. A 3D numerical modeling considers
incompressible, turbulent and steady-state flow. The compact heat exchanger is evaluated for staggered circular
and elliptical tubes. The wavy inclination investigated are -25 °, -20 °, -15 °, -10 °, 10 °, 15 °, 20 ° and 25 °. The
heat transfer is performed by the Colburn factor (j) and the pressure loss penalty is performed by the friction
factor (f). Compared to the conventional heat exchanger (θ = 0 °), the results showed an increase in the heat
transfer of 13.5% with elliptical tubes and 7.8% with circular tubes at wavy inclination of -25 °. For the friction
factor, all inclinations led to a decrease, with a reduction of 18.8% with circular tubes and 15.1% with elliptical
tubes. Overall, the wavy inclination proposed is an effective alternative to both increase the heat transfer and
reduce the pressure losses.