Thermal Performance of Fractal Fins in a Natural Convection Environment

Heat sinks and fins are often utilized to passively dissipate waste heat in electronic systems. It is critically important to dissipate waste heat from electronic devices in order to improve reliability and prevent premature failure of system components. Heat sinks and fins enhance heat transfer from a surface by exposing a larger surface area to convection and radiation. When designing heat sinks, it is often desirable to use the least volume and mass of material. This can be a challenging task as convective heat transfer is directly proportional to the available surface area. When certain fractal geometries are used in the design of fins or heat sinks the surface area available for heat transfer can be increased while system mass can be simultaneously decreased. In a previous investigation it was hypothesized that fractal geometries could be used in the design of fins and heat sinks to increase heat dissipation without increasing the mass and volume of thermal management systems. In order to assess the thermal performance of fractal fins for application in the thermal management of electronic devices an experimental investigation was performed. The experimental investigation assessed the efficiency and effectiveness of straight rectangular fins inspired by the first four iterations of the Sierpinski carpet fractal pattern. The thermal performance of the fractal fins was investigated in a natural convection environment. Natural convection is a type of heat transfer in which fluid motion is not generated by an external source but only by temperature gradients that result in density gradients. While fin efficiency was found to decrease with fractal iteration fin effectiveness per unit mass increased with fractal iteration. In addition, a fractal fin inspired by the fourth iteration of the Sierpinski carpet fractal pattern is more effective than a traditional straight rectangular fin of equal width, height, and thickness. Fractal fins can thus conclusively be used in thermal management applications to simultaneously increase heat transfer and decrease system mass