Thermal effectiveness and mass usage of horizontal micro-fins under natural convection

In recent times, the micro-technologies have gained prominence in various engineering applications. The micro-technologies are already in use for cooling purposes in several systems, but the information on the thermal performance of micro-fins under natural convective heat transfer conditions is yet limited. The correlations between heat transfer coefficients and fin geometry have already been investigated, but are not sufficient to optimize the design of the micro-finned arrays. For this reason, the present investigation gives an overview of micro-fins behavior taking into account, for the first time, different heat sink metrics: the fin effectiveness and the mass specific heat transfer coefficient. The results of an original experimental investigation are merged with the data available in literature. Natural convective micro-fins are able to achieve overall fin effectivenesses higher than 1.1. Even if not always beneficial in terms of heat transfer, micro-fins are found always positive in terms of the material usage. In this light, micro-fins can be considered advantageous in those applications that require a minimized weight of the heat sinks. Moreover, a limited effect due to the orientation is observed.