Design and numerical investigations of natural convection heat transfer of a new rippling fin shape

In the present work, a new fin shape is proposed to improve the convective heat transfer in heat sinks and to reduce their weight. The problem under consideration is a natural convection with air as the working fluid. Three-dimensional numerical simulations are carried out using FLUENT 19.0, to solve the continuity, momentum, turbulence, and energy equations to predict the flow and temperature field for different fins on a vertical base. Five configurations of rippling fins are considered with two aspect ratios and different heat flux inputs. The numerical results are compared to previous data available in the literature for a vertical rectangular finned plate (reference case) to validate the model. For each configuration, the heat sink temperature field and the natural convection driven air flow are discussed. The heat flux is varied from 519.396 W/m(2) to 4674.565 W/m(2). The overall thermal performance is characterized by the heat dissipation rate per unit mass. By comparison to conventional rectangular fin, the proposed fin geometry can reduce the temperature at the heat sink base by up to 18.35 K, increase the mass specific heat transfer coefficient by up to 101.41%, and decreases the thermal resistance by 9.81%. Within the scope of this study. The case with one ripple provides the best thermal performance. The results also showed that, the flow and heat transfer enhancements are a decreasing function of Rayleigh number. Overall, the heat transfer enhancement is better with rippling fins than with the rectangular fins, with a maximal mass reduction of 47%. The proposed models provide a practical alternative to the widely adopted plate fin heat sinks, which very promising for future thermal developments.