Villanova University, 800 Lancaster Ave., Villanova, PA 19085, USA
Inspired by the water transportation in trees, a theoretical model for designing a passive water harvesting network is proposed here. By mimicking the architecture of the tree (root, trunk, and canopy), the capillary-driven network is generated to extract the maximum mass flow rate going from multiple inlets at the water reservoir to multiple outlets in the tree canopy. The effect of the network configuration is investigated under the same fluid volume, and network footprint. The mass flow rate and total pressure loss from inlets to outlets are documented. The Capillary Strength is defined as a local indicator to assess each conduit's ability to sustain its share of the overall mass flow rate. It is found that the radius ratio of consecutive branches follows the Hess-Murray's law, except for the ones near the outlet. The canopy must be entirely redesigned, rather than have the same geometry as the root, in order to allow the fluid to reach the outlets at a maximum mass flow rate. When compared to parallel and radial
structures with the same fluid volume and network footprint, the dendritic tree is proven to be superior for maximum fluid harvesting.