José Carlos Páscoa

The escalating demand for enhanced cooling systems, particularly in high-power computer processors, necessitates innovative solutions within the spatial constraints of computing environments. This paper introduces a design modification that strategically diverts a portion of the main flow toward and through the porous fin region, creating a “cross flow.” The novel approach aims to maximize heat transfer through the fins, harnessing both conduction and convection heat transfer mechanisms. The realization of these flow patterns is achieved through interdigitated blocking of the inlet and outlet reigns of the microchannel, coupled with the utilization of converging and diverging microchannel porous fins in distinct elbow and zigzag geometrical configurations. Numerical simulations using computational fluid dynamics are employed to assess the proposed microchannel heat sink's thermo-hydraulic performance. The proposed design innovation significantly enhances heat dissipation efficiency by augmenting the convection heat transfer mechanism within the porous fins, resulting in a remarkable 17% improvement in Nusselt number compared to conventional parallel microchannel heat sinks with porous fins. This study provides valuable insight into the thermal and hydraulic performance of the proposed design, offering promising prospects for addressing the escalating demand for enhanced cooling systems in high-power computing environments.

Flow field design is crucial for achieving higher performance in polymer electrolyte membrane fuel cells (PEMFCs). This study uses a two‐phase, multi‐component, and three‐dimensional model to simulate the performance of PEMFCs that use interdigitated flow field design with intermediate blocks on the cathode side. A detailed parametric study is presented to investigate the effects of various geometric and operational parameters. Of the parameters studied, inlet mass flow rate, relative humidity, and rib width had the greatest impact on cell performance. The results show that increasing the cathode stoichiometric ratio resulted in higher fuel cell performance for blocked interdigitated designs compared to parallel designs. In addition, using cathode channels with higher height values resulted in lower PEMFC performance for all flow fields. Higher values of rib/channel width ratio resulted in lower cell performance due to liquid water accumulation in the rib regions. However, at higher rib/channel width ratios, the positive effect of using interdigitated flow designs was more pronounced. Moreover, at a low relative humidity of RH = 25%, a 10.4% higher performance was obtained for the interdigitated type II compared to cases with RH = 100%, due to more effective over‐rib convection and higher water removal.